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RELATED APPLICATION
This application claims the benefit of U.S. provisional application Ser. No. 61/191,591.
FIELD OF THE INVENTION
The invention is in the field of electrooptical displays and ways in which the displays are designed to enable interconnection by display electronics to electrically conductive layers of the display.
BACKGROUND
Liquid crystal display (LCD) modules are becoming more and more highly used in everyday life and work. To create images on LCD screens the LCD must be electrically connected to the display electronics to create a completed module. There are several typical techniques for electrically interconnecting the LCD and electronics, including; chip on glass (COG), where the display driver chip is physically bonded to the display's electrical traces on the display substrate. Another technique is to physically bond the display substrate to a flexible polyimide material, called a flex, which has embedded copper traces and pads. If the flex technique is used then the remaining unbounded end of the flex must be connected to a PCB or TAB that contains the display driver chip. An interconnect technique must be used for each of the display substrates, resulting in two bonding steps and two sets of driver chips for each display. It is possible to electrically connect one substrate's leads to the other substrate's leads (referred to as indium-tin oxide (ITO) traces, but can also be other transparent conductors such as conducting polymer, carbon nanotubes or others), which is referred to as an electrical cross-over. This is particularly useful when there are a smaller amount of total ITO traces for the LCD and then only one substrate requires physical bonding to either the COG or the flex. An electrical cross-over allows for a reduction of interconnect steps and materials used and thus, represents a cost reduction.
A common technique to electrically cross-over an LCD containing glue gasket around the perimeter is to place conductive spheres, or spacers, in that gasket. Therefore, the conductive spheres are held in one location in the display. In this situation ITO traces from both substrates touch the conductive spheres, allowing for an electrical connection between traces on both the substrates. This technique requires that the LCD uses a gasket around the perimeter.
Instead of electrically crossing-over one can also use one piece of flex to connect to both substrates. In this case the flex must have vias in it to allow connection to all traces on either the top or bottom side of the flex. Vias are in a simplistic sense a hole drilled in the polyimide that is then filled with copper, such that the copper filled hole has copper traces on both sides of the flex that come into contact with the via. This technique allows the display driver chips to be located on a PCB and requires fewer driver chips, thus reducing cost. However, a flex containing vias is typically very expensive.
To use as few display driver chips and interconnect processes for the least possible cost on a display that does not use a gasket around the perimeter a new type of electrical cross-over is required.
TECHNICAL DISCLOSURE
We disclose a technique of electrically switching a plastic display by electrically connecting to only one plastic substrate. The electrical display comprises one or two substrates with conductive layers facing one another that are held apart by a liquid crystal layer. This invention allows a simple interconnect solution that is easy to assemble to the display and economical. Typical interconnect solutions require electrically connecting the flex to both of the display substrates.
In general, the invention features an electrooptical display with electrical cross-over. A substrate has a display area of overlapping conductive layers, a cross-over region designated for electrical cross-over and a bonding area for bonding display electronics to the conductive layers. A first conductive layer of electrically conductive material is disposed on the substrate in the display area and in the bonding area. An electrical cross-over member is disposed in the bonding area and in the cross-over region and comprises a cross-over conductor formed over the substrate. The cross-over conductor comprises a cured, solid conductive material that has a topography of peaks and valleys. An optically active layer is disposed on the first conductive layer and the cross-over conductor. The optically active layer includes electrooptical material dispersed in a polymeric matrix. A second conductive layer of electrically conductive material is disposed on the optically active layer in the display area and in the cross-over region. The valleys of the cross-over conductor receive the electrooptical material, and the peaks are in electrical contact with the second conductive layer.
In all embodiments of the invention the display may include only a single substrate with or without an uppermost polymeric protective layer, or it may include two or more substrates. A substrate as defined herein is a structure that supports components of an electrooptical (e.g., liquid crystal) display including an electrooptical layer that is electrically addressed to produce images. The substrate need not be rigid but can be flexible or drapable as disclosed in U.S. Pat. No. 7,236,151, which is incorporated herein by reference in its entirety. Glass, metal, polymer, paper and fabric or textile can all be used as substrate materials. The substrate is a generally thin layer, but is often significantly thicker than other components of the display. As defined herein a substrate is a layer that has a thickness of at least 10 microns and, in particular, at least 20 microns or at least 50 microns. Substrates of liquid crystal displays on the market today can have a thickness of 100 microns or more and substrates such as fabrics can be substantially thicker exceeding 1000 microns. The substrate can be formed of or have various components attached to it such as electrodes, an active matrix backplane, solar cell, photovoltaic device and the like. It will be appreciated that in all embodiments of the invention at least one of the electrically conductive layers of the display is transparent and at least one of the substrates is transparent. Terms such as bottom, top, under, over and the like used herein are only used to improve understanding and should not limit the invention.
A first embodiment of the invention features an electrooptical display with electrical cross-over, for example, in the case of a liquid crystal display with unpatterned electrically conductive layers. A substrate has a display area of overlapping conductive layers, a cross-over region designated for electrical cross-over and a bonding area for bonding display electronics to the electrically conductive layers. A first conductive layer of electrically conductive material is disposed on the substrate in the display area and in the bonding area. An electrical cross-over member is disposed in the bonding area and in the cross-over region and comprises an insulating layer of electrically insulating material disposed on the first conductive layer and a cross-over conductor disposed on the insulating layer. The cross-over conductor comprises a cured, solid conductive material that has a topography of peaks and valleys. An optically active layer is disposed on the first conductive layer and the cross-over conductor. The optically active layer includes: electrooptical material dispersed in a polymeric matrix, and nonconductive spacers. A second conductive layer of electrically conductive material is disposed on the optically active layer in the display area and in the cross-over region. The valleys of the cross-over conductor receive the electrooptical material and the spacers. The peaks are in electrical contact with the second conductive layer.
A second embodiment features an electrooptical display with electrical cross-over having patterned electrically conductive layers. A substrate has a display area including parallel row electrodes and parallel column electrodes. The row electrodes are spaced apart from and orthogonal to the column electrodes. The display can also have directly driven segments in place of the row and column electrodes and in this case the bonding area will be the same. The substrate includes a cross-over region designated for electrical cross-over and a bonding area for bonding display electronics to the row electrodes and the column electrodes. A first conductive layer includes a plurality of spaced apart traces of electrically conductive material disposed in the bonding area on the substrate and leading to the row electrodes or the column electrodes. An electrical cross-over member is disposed in the bonding area and in the cross-over region on the substrate and comprises a second conductive layer including a plurality of spaced apart traces of electrically conductive material and a cross-over conductor disposed in electrical contact on the traces of the second conductive layer. The cross-over conductor comprises a cured, solid conductive material that has a topography of peaks and valleys. An optically active layer is disposed on the first conductive layer and the cross-over conductor. The optically active layer includes electrooptical material dispersed in a polymeric matrix. A third conductive layer includes a plurality of spaced apart traces of electrically conductive material disposed on the optically active layer and extends from the cross-over region to the other of the row electrodes or the column electrodes. The valleys of the cross-over conductor receive the electrooptical material, and the peaks are in electrical contact with the third conductive layer. The traces of the third conductive layer are in alignment with the traces of the second conductive layer in the cross-over region.
Referring to specific aspects of the first and second embodiments, the display can further comprise a protective layer of material disposed on the second conductive layer or on the third conductive layer, for example, forming an outer layer of the display. The protective layer can form a second substrate and it, along with the first substrate, can be formed of polymeric material. At least one of the substrate and the protective layer is transparent and at least one of the first, second and third conductive layers is transparent.
The electrooptical material can be a liquid crystal material. One suitable liquid crystal material is bistable cholesteric liquid crystal material. Other possible liquid crystal materials are smectic or nematic. The liquid crystal material can be a polymer stabilized cholesteric texture or a polymer dispersed liquid crystal. The electrooptical material can be an electrophoretic material or an electrowetting material.
The cross-over conductor can have a roughness between 1 and 200 μm Ra, more particularly, between 2 and 12 microns Ra.
The electrical cross-over member can comprise a second cross-over conductor having a flat surface that contacts the second or the third conductive member so that the topology of the second cross-over conductor engages the topology of the first cross-over conductor. This prevents burnout of the electrically conductive material due to application of voltage at point contacts of the peaks of the cross-over conductor with the electrically conductive layer.
Another embodiment of the invention is a method of making an electrical cross-over in an electrooptical display. A substrate is provided having a display area of overlapping conductive layers, a cross-over region designated for electrical cross-over and a bonding area for bonding display electronics to the electrically conductive layers. A first conductive layer of electrically conductive material is formed on the substrate in the display area and in the bonding area. An electrical cross-over member is formed in the bonding area and in the cross-over region by applying an insulating layer of electrically insulating material on the first conductive layer and a conductive material that has a topography of peaks and valley on the insulating layer. The conductive material that has the topography of peaks and valleys is cured into a solid to form the cross-over member. A fluid optically active layer is applied on the first conductive layer and the cross-over conductor. The optically active layer includes: electrooptical material dispersed in a polymeric matrix, and nonconductive spacers. The fluid electrooptical material and the spacers are filled into the valleys of the cross-over conductor. A second conductive layer of electrically conductive material is applied on the optically active layer in the display area and in the cross-over region so that the peaks of the cross-over conductor are in electrical contact with the second conductive layer. Lastly, the polymer of the electrooptical layer is cured so as to harden.
Yet another embodiment features a method of making an electrical cross-over in an electrooptical display having patterned electrically conductive layers. A substrate is provided having a display area including parallel row electrodes and parallel column electrodes (or directly driven segments). The row electrodes are spaced apart from and orthogonal to the column electrodes. The substrate includes a cross-over region designated for electrical cross-over and a bonding area for bonding display electronics to the row electrodes and the column electrodes. A first conductive layer includes a plurality of spaced apart traces of electrically conductive material disposed in the bonding area on the substrate and leading to the row electrodes or the column electrodes. An electrical cross-over member is applied in the bonding area and in the cross-over region on the substrate comprising applying to the substrate a second conductive layer including a plurality of spaced apart traces of electrically conductive material and applying a conductive material that has a topography of peaks and valleys in electrical contact on the traces of the second conductive layer. The conductive material that has the topography of peaks and valleys is cured into a solid to form the cross-over conductor. A fluid optically active layer is applied on the first conductive layer and on the cross-over conductor. The optically active layer includes electrooptical material dispersed in a polymeric matrix. The fluid optically active material is filled into the valleys of the cross-over conductor. A third conductive layer including a plurality of spaced apart traces of electrically conductive material is applied on the optically active layer such that the peaks of the cross-over conductor are in electrical contact with the third conductive layer. The traces of the third conductive layer are aligned with the traces of the second conductive layer in the cross-over region. The third conductive layer extends from the cross-over region to the other of the row electrodes or the column electrodes. Lastly, the polymer of the optically active layer is cured so as to harden.
Many additional features, advantages and a fuller understanding of the invention will be had from the accompanying drawings and the detailed description that follows. It should be understood that the above Technical Disclosure describes the invention in broad terms while the following Detailed Description describes the invention more narrowly and presents specific embodiments that should not be construed as necessary limitations of the invention as broadly defined in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B show a typical liquid crystal display with a ledge on each substrate to interconnect to a flexible connector;
FIGS. 2A and 2B show the inventive technique of electrically connecting to a display by attaching to only one substrate;
FIG. 3 shows a cross-sectional view as seen along the cutting plane defined by the lines and arrows 3 A- 3 A in FIG. 2B indicating how a roughness of a cross-over conductive layer that is part of the electrical cross over allows connection to the electrically conductive layer of the top substrate;
FIG. 3B shows a cross-sectional view as seen along the cutting plane defined by the lines and arrows 3 B- 3 B in FIG. 2B indicating the position of a second upper cross-over conductor;
FIG. 4 shows a cross-sectional side view as seen along the cutting plane as defined by the lines and arrows 4 - 4 of FIG. 2B revealing that the electrical cross over has two layers: a dielectric layer and a conductive layer;
FIG. 5 is a top plan view of the display of FIGS. 2A and 2B showing how a flexible conductive member is electrically connected to the electrically conductive material on one of the ledges and to the electrical cross-over member on the other ledge;
FIG. 6 is a cross-sectional view as seen along the cutting plane defined by the lines and arrows 6 - 6 in FIG. 5 ;
FIG. 7 is a top plan view of electrical traces and, for example, row electrodes formed on a bottom substrate along with electrical traces of a component of an electrical cross-over member;
FIG. 8 is a top plan view of electrical traces and, for example, column electrodes formed on a top substrate;
FIG. 9 is a top plan view of the top substrate of FIG. 8 overlaying the bottom substrate of FIG. 7 ; and
FIG. 10 is a cross-sectional view as seen along the cutting plane defined by the lines and arrows 10 - 10 in FIG. 9 .
The figures are not drawn to scale.
DETAILED DESCRIPTION
FIGS. 1A and 1B (Prior Art) illustrate a typical plastic liquid crystal display with unpatterned electrically conductive layers (not shown). There are two substrates each with a conductive layer formed on them. The conductive layers are separated by a thin liquid crystal layer (not shown). The top substrate 10 and the bottom substrate 12 each have a small section of substrate or ledge 14 , 16 that is exposed and protrudes from the display for the purpose of electrical connection to the display. The electrically conductive layers are on each of the ledges. The top substrate 10 has the conductive layer facing down, while the bottom substrate 12 has the conductive layer facing up. Once the display 18 is assembled each substrate has its ledge exposed and protruding from the display. A display assembled in this fashion requires an interconnect facing down for the bottom substrate 12 and an interconnect facing up for the top substrate 10 or a single flex containing a via.
FIGS. 2A and 2B illustrate a plastic display with unpatterned electrically conductive layers and with the inventive technique of electrically connecting to the electrically conductive layer of only one substrate 20 . There are two substrates each formed with a conductive layer. The conductive layers are separated by a thin liquid crystal layer. The top substrate 22 has no exposed section or ledge that protrudes from the display. The bottom substrate 20 has two small sections or ledges 24 , 26 exposed that protrude from the display for the purpose of electrical connection to the display. The bottom substrate 20 also has the electric cross-over member 28 that electrically connects to the top substrate. The top substrate 22 has the conductive layer facing down, while the bottom substrate 20 has the conductive layer facing up. Once the display 30 is assembled only the bottom substrate has two ledges exposed that protrude from the display, where one is for electrical connection 32 to the bottom substrate and the other is for electrical connection 34 to the top substrate.
Both a dielectric, electrically insulating layer 36 and an electrically conductive cross-over conductor layer 38 make up the electrical cross over member 28 . The dielectric and electrically conductive material are coated on the substrate 20 and have a ledge 24 under the coating to create the cross over.
FIG. 3A illustrates a close-up of the electrical cross over member 28 . The cross-over conductor 38 allows spacers 40 used in the display to fall into valleys 42 created by the rough surface. Since the spacers 40 are trapped in valleys that are deeper than the diameter of the spacers a top electrically conductive layer 44 comes in electrical contact with peaks 43 of the cross-over conductor 38 . The top electrically conductive layer 44 is coated on the top substrate 22 and a bottom electrically conductive layer 46 is coated over the bottom substrate 20 . In all embodiments of the invention, techniques for applying the electrically conductive layers and the liquid crystal layer (e.g., coating and printing techniques) include those disclosed in U.S. Pat. No. 7,170,481, which is incorporated herein by reference in its entirety.
FIG. 3B illustrates a variation of the electrical cross-over member 28 . The cross-over member 28 includes another upper cross-over conductor 38 but inverted from its orientation in FIG. 3A so that its flat upper surface is in electrical contact with the upper electrically conductive member 44 and its lower surface contacts the upper surface of the other cross-over conductor 38 . Peaks of the upper cross-over conductor can engage valleys of the lower cross-over conductor and vice versa. Liquid crystal material and spacers are present in the valleys of the upper cross-over conductor. This prevents burnout of the electrically conductive material due otherwise to application of voltage at point contacts of the peaks of the cross-over conductor with the electrically conductive layer. The upper surface of the upper cross-over conductor engages the upper electrically conductive layer 44 as a flat surface. This same use of a second cross-over conductor can be used in the second embodiment shown in FIG. 10 except that the upper flat surface of the upper cross-over conductor would electrically contact the third electrically conductive layer.
FIG. 4 illustrates a side cross-sectional view of the electrical crossover member 28 . The dielectric layer 36 prevents the top and bottom substrates from shorting together. Next to the dielectric layer 36 and the cross-over conductor 38 is the electrooptical material (e.g., liquid crystal material) 48 . All of the electrooptical material of this disclosure has the same characteristics and is dispersed in a polymeric matrix. A suitable display is an electrooptical material forming a bistable display. Examples of liquid crystal materials are cholesteric, nematic and smectic. A specific display suitable for use in the present invention is a bistable cholesteric liquid crystal display. As will be apparent to those of ordinary skill in the art in view of the instant disclosure, the liquid crystal material will preferably be present in the displays of the invention in the form of liquid crystalline layers comprised of a liquid crystal dispersion and, most preferably, a cholesteric droplet dispersion. There are many different approaches to the formation of a layer of liquid crystal droplets, some of which have been used for cholesteric liquid crystals. To form such a liquid crystal layer, the liquid crystal can be microencapsulated, formed into a layer of phase separated liquid crystal droplets, or formed into emulsified droplets of liquid crystal. More specifically, one process suitable for forming liquid crystal layers for use in the invention is phase separation, which is basically a process that involves mixing the cholesteric liquid crystalline material with a pre-polymer solution then polymerizing the polymer under suitable conditions to form a dispersion of droplets in a polymer binder. Polymerization and, hence, droplet formation, occurs after the material mixture has been coated onto the display. There are basically three types of polymerization techniques that can be used depending on the polymer (or monomer): (1) thermally induced phase separation (TIPS); (2) polymerization induced phase separation (PIPS); and, (3) solvent induced phase separation (SIPS), for example as disclosed in U.S. Pat. No. 7,170,481. A bistable display is one having at least two states that are stable in an absence of an electric field. Examples of other electrooptical materials that can be used in an electrooptical display instead of liquid crystal material are electrophoretic or electrowetting materials. In FIG. 4 , notice that the section of bottom substrate 20 that is exposed and protrudes from the display 30 for electrical connection to the top substrate 22 is also shown.
A display area of the display 30 is located where the upper and lower electrically conductive layers 44 , 46 overlap having the electrooptical material 48 disposed between them. A bonding area is where the bottom electrically conductive layer 46 protrudes from the upper substrate 22 on ledge 26 and where the cross-over conductor 38 protrudes from the upper substrate on ledge 24 . A cross-over region 29 is where the cross-over member 28 extends under the conductive layer, coated top substrate 22 .
FIGS. 5 and 6 illustrate how the display's conductive ledges 24 , 26 connect to a flexible electronic conductor (“flex”) 50 . The flex has conductive pads 52 that are connected to the display's conductive ledges using a conductive adhesive or anisotropic conductive film 53 . The conductive pads face toward the display away from the viewer in this figure. The conductive pads have conductive traces 54 that connect to them on the flex 50 , allowing electrical connection to the display through the end of the flex. The flex 50 is made up of conductive pads 52 , conductive traces 54 , and a flexible plastic film 56 . Once the display is connected to the flex, the flex can be connected to a PCB containing LCD driver chips through the traces on the flex. Other ways of bonding display electronics to the electrical traces in the bonding areas are encompassed by this invention and would be apparent to those skilled in the art in view of this disclosure. Top substrate 10 is transparent as are the traces used on the top and bottom substrate. The traces can be formed of transparent conductive material such as conductive polymer, carbon nanotubes or indium tin oxide (ITO).
Referring to a second embodiment of the invention, FIG. 7 illustrates the patterned conductive traces 60 formed on a top surface of a bottom substrate 62 of a patterned display that uses this invention. This substrate 62 is electrically connected to the circled trace region at 64 . The opposite top substrate 66 ( FIG. 8 ) is electrically connected to the patterned conductive traces in the circled region 68 .
FIG. 8 illustrates patterned conductive traces 70 formed on a bottom surface of the top substrate of a patterned display that uses this invention. Top substrate 66 is transparent as are the traces used on the top and bottom substrate. The traces can be formed of transparent conductive material such as conductive polymer, carbon nanotubes or indium tin oxide (ITO). The upper substrate 66 is electrically connected to the traces on the bottom substrate at 68 ( FIG. 7 ). Conductive traces 72 on the bottom substrate 62 electrically connect in the z direction (in and out of the paper in the top views) to the patterned conductive traces of the top substrate shown in the circled region 74 . A layer of liquid crystal material is disposed between the layers of conductive traces formed on the bottom and top substrates, but is confined to the region bounded by the top substrate ( FIG. 8 ).
Row electrodes 76 , for example, are formed by the conductive traces 60 on the bottom substrate 62 while column electrodes 78 , for example, are formed by the conductive traces 70 on the top substrate 66 .
FIG. 9 illustrates the top and bottom substrates overlayed forming a patterned display 80 . The region of crossing row and column electrodes is the display area 81 . The region to the left of the top substrate comprised of only the bottom substrate is the bonding area (i.e., regions 68 and 64 ). The region shown at 82 is a portion of a cross-over region having an electrical connection between electrically conductive layers formed on the top and bottom substrates in the z direction with the traces 72 from the bottom substrate in region 68 and traces 70 from the top substrate 66 in the region 74 .
As shown in FIG. 10 , the patterned conductive traces 72 for the bottom substrate 62 are shown electrically connected to the patterned conductive traces 70 on the top substrate 66 in regions 68 and 74 through a patterned cross-over conductor 84 with a roughened top surface that forms a topography of peaks 85 and valleys 86 . This figure shows how liquid crystal 87 surrounds the patterned conductive traces 72 , 70 and fills in the valleys 86 of the cross-over conductor. Notice that a dielectric layer is not required for the patterned conductor display. The bonding areas 68 , 64 of the display 80 can be connected to flex as in the case of the unpatterned display of the first embodiment ( FIGS. 2A and 2B ), and the flex can be connected to a PCB containing LCD driver chips through the traces of the flex. Other ways of bonding display electronics to the electrical traces in the bonding areas are encompassed by this invention and would be apparent to those skilled in the art in view of this disclosure.
The invention will now be described with regard to the following example which should not be interpreted so as to limit the invention.
EXAMPLE
A flexible plastic LCD was constructed using a crossover member to electrically connect the top substrate to a trace on the bottom substrate. A UV-curable dielectric material (DuPont 5018) was screen printed onto a 2 mil PET substrate gravure coated with Agfa S300 PEDOT mixed with 0.15% Silquest A-187 silane by volume. The print was executed by traversing an 80-durometer rectangular squeegee positioned at 45° over a 105 mesh stainless steel screen. The dielectric print was cured under an Electro-Lite UV lamp without the manufacturer's filter in place at 8.0 mW/cm 2 for two minutes. A conductive carbon paste (DuPont 7102) was used to screen print a trace on top of the cured dielectric layer in the same manner using a 195 mesh polyester screen. The carbon trace was cured in an oven for five minutes at a temperature of 130 C. Upon curing, no conductivity was measured between the carbon trace and the PEDOT beneath the dielectric layer.
The display was made using a second 2 mil PET substrate gravure coated with Agfa S300 PEDOT mixed with 0.15% Silquest A-187 silane by volume. A PIPS mixture of liquid crystal with 4.0 μm spacers mixed in (2.5% by volume) was laminated between the two substrates. The PIPS mixture of liquid crystal was applied as a fluid onto the lower electrically conductive layer and the carbon trace and then when the electrically conductive coated upper substrate was laminated onto it the liquid crystal and spacers flowed inside valleys of the carbon trace. Alternatively, the PIPS mixture of liquid crystal fluid could be applied to the electrically conductive coated upper substrate. The top substrate was laminated so it covered only part of the carbon trace, leaving the rest exposed for switching purposes. A second trace was left exposed on the bottom substrate that had only PEDOT on it. The display was cured under an Electro-Lite UV lamp at an intensity of 0.92 mW/cm 2 for 20 minutes. Both traces were painted with conductive silver paint and a pulse of 40V, 30 ms, 33 Hz was applied to the exposed silver paint over the conductive carbon paste (top substrate electrically conductive layer) and to the exposed silver paint over the electrically conductive layer (bottom substrate electrically conductive layer).
Many modifications and variations of the invention will be apparent to those of ordinary skill in the art in light of the foregoing disclosure. Therefore, it is to be understood that, within the scope of the appended claims, the invention can be practiced otherwise than has been specifically shown and described. | Electrooptical displays require conductors on both sides of the liquid crystal thin film. The two conductors face opposite sides of the display. The cost of electrically connecting to these displays can be decreased by having the conductors of the display all face the same side of the display. This invention includes a technique to allow both conductors to face the same side of the display. | Briefly describe the main invention outlined in the provided context. | [
"RELATED APPLICATION This application claims the benefit of U.S. provisional application Ser.",
"No. 61/191,591.",
"FIELD OF THE INVENTION The invention is in the field of electrooptical displays and ways in which the displays are designed to enable interconnection by display electronics to electrically conductive layers of the display.",
"BACKGROUND Liquid crystal display (LCD) modules are becoming more and more highly used in everyday life and work.",
"To create images on LCD screens the LCD must be electrically connected to the display electronics to create a completed module.",
"There are several typical techniques for electrically interconnecting the LCD and electronics, including;",
"chip on glass (COG), where the display driver chip is physically bonded to the display's electrical traces on the display substrate.",
"Another technique is to physically bond the display substrate to a flexible polyimide material, called a flex, which has embedded copper traces and pads.",
"If the flex technique is used then the remaining unbounded end of the flex must be connected to a PCB or TAB that contains the display driver chip.",
"An interconnect technique must be used for each of the display substrates, resulting in two bonding steps and two sets of driver chips for each display.",
"It is possible to electrically connect one substrate's leads to the other substrate's leads (referred to as indium-tin oxide (ITO) traces, but can also be other transparent conductors such as conducting polymer, carbon nanotubes or others), which is referred to as an electrical cross-over.",
"This is particularly useful when there are a smaller amount of total ITO traces for the LCD and then only one substrate requires physical bonding to either the COG or the flex.",
"An electrical cross-over allows for a reduction of interconnect steps and materials used and thus, represents a cost reduction.",
"A common technique to electrically cross-over an LCD containing glue gasket around the perimeter is to place conductive spheres, or spacers, in that gasket.",
"Therefore, the conductive spheres are held in one location in the display.",
"In this situation ITO traces from both substrates touch the conductive spheres, allowing for an electrical connection between traces on both the substrates.",
"This technique requires that the LCD uses a gasket around the perimeter.",
"Instead of electrically crossing-over one can also use one piece of flex to connect to both substrates.",
"In this case the flex must have vias in it to allow connection to all traces on either the top or bottom side of the flex.",
"Vias are in a simplistic sense a hole drilled in the polyimide that is then filled with copper, such that the copper filled hole has copper traces on both sides of the flex that come into contact with the via.",
"This technique allows the display driver chips to be located on a PCB and requires fewer driver chips, thus reducing cost.",
"However, a flex containing vias is typically very expensive.",
"To use as few display driver chips and interconnect processes for the least possible cost on a display that does not use a gasket around the perimeter a new type of electrical cross-over is required.",
"TECHNICAL DISCLOSURE We disclose a technique of electrically switching a plastic display by electrically connecting to only one plastic substrate.",
"The electrical display comprises one or two substrates with conductive layers facing one another that are held apart by a liquid crystal layer.",
"This invention allows a simple interconnect solution that is easy to assemble to the display and economical.",
"Typical interconnect solutions require electrically connecting the flex to both of the display substrates.",
"In general, the invention features an electrooptical display with electrical cross-over.",
"A substrate has a display area of overlapping conductive layers, a cross-over region designated for electrical cross-over and a bonding area for bonding display electronics to the conductive layers.",
"A first conductive layer of electrically conductive material is disposed on the substrate in the display area and in the bonding area.",
"An electrical cross-over member is disposed in the bonding area and in the cross-over region and comprises a cross-over conductor formed over the substrate.",
"The cross-over conductor comprises a cured, solid conductive material that has a topography of peaks and valleys.",
"An optically active layer is disposed on the first conductive layer and the cross-over conductor.",
"The optically active layer includes electrooptical material dispersed in a polymeric matrix.",
"A second conductive layer of electrically conductive material is disposed on the optically active layer in the display area and in the cross-over region.",
"The valleys of the cross-over conductor receive the electrooptical material, and the peaks are in electrical contact with the second conductive layer.",
"In all embodiments of the invention the display may include only a single substrate with or without an uppermost polymeric protective layer, or it may include two or more substrates.",
"A substrate as defined herein is a structure that supports components of an electrooptical (e.g., liquid crystal) display including an electrooptical layer that is electrically addressed to produce images.",
"The substrate need not be rigid but can be flexible or drapable as disclosed in U.S. Pat. No. 7,236,151, which is incorporated herein by reference in its entirety.",
"Glass, metal, polymer, paper and fabric or textile can all be used as substrate materials.",
"The substrate is a generally thin layer, but is often significantly thicker than other components of the display.",
"As defined herein a substrate is a layer that has a thickness of at least 10 microns and, in particular, at least 20 microns or at least 50 microns.",
"Substrates of liquid crystal displays on the market today can have a thickness of 100 microns or more and substrates such as fabrics can be substantially thicker exceeding 1000 microns.",
"The substrate can be formed of or have various components attached to it such as electrodes, an active matrix backplane, solar cell, photovoltaic device and the like.",
"It will be appreciated that in all embodiments of the invention at least one of the electrically conductive layers of the display is transparent and at least one of the substrates is transparent.",
"Terms such as bottom, top, under, over and the like used herein are only used to improve understanding and should not limit the invention.",
"A first embodiment of the invention features an electrooptical display with electrical cross-over, for example, in the case of a liquid crystal display with unpatterned electrically conductive layers.",
"A substrate has a display area of overlapping conductive layers, a cross-over region designated for electrical cross-over and a bonding area for bonding display electronics to the electrically conductive layers.",
"A first conductive layer of electrically conductive material is disposed on the substrate in the display area and in the bonding area.",
"An electrical cross-over member is disposed in the bonding area and in the cross-over region and comprises an insulating layer of electrically insulating material disposed on the first conductive layer and a cross-over conductor disposed on the insulating layer.",
"The cross-over conductor comprises a cured, solid conductive material that has a topography of peaks and valleys.",
"An optically active layer is disposed on the first conductive layer and the cross-over conductor.",
"The optically active layer includes: electrooptical material dispersed in a polymeric matrix, and nonconductive spacers.",
"A second conductive layer of electrically conductive material is disposed on the optically active layer in the display area and in the cross-over region.",
"The valleys of the cross-over conductor receive the electrooptical material and the spacers.",
"The peaks are in electrical contact with the second conductive layer.",
"A second embodiment features an electrooptical display with electrical cross-over having patterned electrically conductive layers.",
"A substrate has a display area including parallel row electrodes and parallel column electrodes.",
"The row electrodes are spaced apart from and orthogonal to the column electrodes.",
"The display can also have directly driven segments in place of the row and column electrodes and in this case the bonding area will be the same.",
"The substrate includes a cross-over region designated for electrical cross-over and a bonding area for bonding display electronics to the row electrodes and the column electrodes.",
"A first conductive layer includes a plurality of spaced apart traces of electrically conductive material disposed in the bonding area on the substrate and leading to the row electrodes or the column electrodes.",
"An electrical cross-over member is disposed in the bonding area and in the cross-over region on the substrate and comprises a second conductive layer including a plurality of spaced apart traces of electrically conductive material and a cross-over conductor disposed in electrical contact on the traces of the second conductive layer.",
"The cross-over conductor comprises a cured, solid conductive material that has a topography of peaks and valleys.",
"An optically active layer is disposed on the first conductive layer and the cross-over conductor.",
"The optically active layer includes electrooptical material dispersed in a polymeric matrix.",
"A third conductive layer includes a plurality of spaced apart traces of electrically conductive material disposed on the optically active layer and extends from the cross-over region to the other of the row electrodes or the column electrodes.",
"The valleys of the cross-over conductor receive the electrooptical material, and the peaks are in electrical contact with the third conductive layer.",
"The traces of the third conductive layer are in alignment with the traces of the second conductive layer in the cross-over region.",
"Referring to specific aspects of the first and second embodiments, the display can further comprise a protective layer of material disposed on the second conductive layer or on the third conductive layer, for example, forming an outer layer of the display.",
"The protective layer can form a second substrate and it, along with the first substrate, can be formed of polymeric material.",
"At least one of the substrate and the protective layer is transparent and at least one of the first, second and third conductive layers is transparent.",
"The electrooptical material can be a liquid crystal material.",
"One suitable liquid crystal material is bistable cholesteric liquid crystal material.",
"Other possible liquid crystal materials are smectic or nematic.",
"The liquid crystal material can be a polymer stabilized cholesteric texture or a polymer dispersed liquid crystal.",
"The electrooptical material can be an electrophoretic material or an electrowetting material.",
"The cross-over conductor can have a roughness between 1 and 200 μm Ra, more particularly, between 2 and 12 microns Ra.",
"The electrical cross-over member can comprise a second cross-over conductor having a flat surface that contacts the second or the third conductive member so that the topology of the second cross-over conductor engages the topology of the first cross-over conductor.",
"This prevents burnout of the electrically conductive material due to application of voltage at point contacts of the peaks of the cross-over conductor with the electrically conductive layer.",
"Another embodiment of the invention is a method of making an electrical cross-over in an electrooptical display.",
"A substrate is provided having a display area of overlapping conductive layers, a cross-over region designated for electrical cross-over and a bonding area for bonding display electronics to the electrically conductive layers.",
"A first conductive layer of electrically conductive material is formed on the substrate in the display area and in the bonding area.",
"An electrical cross-over member is formed in the bonding area and in the cross-over region by applying an insulating layer of electrically insulating material on the first conductive layer and a conductive material that has a topography of peaks and valley on the insulating layer.",
"The conductive material that has the topography of peaks and valleys is cured into a solid to form the cross-over member.",
"A fluid optically active layer is applied on the first conductive layer and the cross-over conductor.",
"The optically active layer includes: electrooptical material dispersed in a polymeric matrix, and nonconductive spacers.",
"The fluid electrooptical material and the spacers are filled into the valleys of the cross-over conductor.",
"A second conductive layer of electrically conductive material is applied on the optically active layer in the display area and in the cross-over region so that the peaks of the cross-over conductor are in electrical contact with the second conductive layer.",
"Lastly, the polymer of the electrooptical layer is cured so as to harden.",
"Yet another embodiment features a method of making an electrical cross-over in an electrooptical display having patterned electrically conductive layers.",
"A substrate is provided having a display area including parallel row electrodes and parallel column electrodes (or directly driven segments).",
"The row electrodes are spaced apart from and orthogonal to the column electrodes.",
"The substrate includes a cross-over region designated for electrical cross-over and a bonding area for bonding display electronics to the row electrodes and the column electrodes.",
"A first conductive layer includes a plurality of spaced apart traces of electrically conductive material disposed in the bonding area on the substrate and leading to the row electrodes or the column electrodes.",
"An electrical cross-over member is applied in the bonding area and in the cross-over region on the substrate comprising applying to the substrate a second conductive layer including a plurality of spaced apart traces of electrically conductive material and applying a conductive material that has a topography of peaks and valleys in electrical contact on the traces of the second conductive layer.",
"The conductive material that has the topography of peaks and valleys is cured into a solid to form the cross-over conductor.",
"A fluid optically active layer is applied on the first conductive layer and on the cross-over conductor.",
"The optically active layer includes electrooptical material dispersed in a polymeric matrix.",
"The fluid optically active material is filled into the valleys of the cross-over conductor.",
"A third conductive layer including a plurality of spaced apart traces of electrically conductive material is applied on the optically active layer such that the peaks of the cross-over conductor are in electrical contact with the third conductive layer.",
"The traces of the third conductive layer are aligned with the traces of the second conductive layer in the cross-over region.",
"The third conductive layer extends from the cross-over region to the other of the row electrodes or the column electrodes.",
"Lastly, the polymer of the optically active layer is cured so as to harden.",
"Many additional features, advantages and a fuller understanding of the invention will be had from the accompanying drawings and the detailed description that follows.",
"It should be understood that the above Technical Disclosure describes the invention in broad terms while the following Detailed Description describes the invention more narrowly and presents specific embodiments that should not be construed as necessary limitations of the invention as broadly defined in the claims.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B show a typical liquid crystal display with a ledge on each substrate to interconnect to a flexible connector;",
"FIGS. 2A and 2B show the inventive technique of electrically connecting to a display by attaching to only one substrate;",
"FIG. 3 shows a cross-sectional view as seen along the cutting plane defined by the lines and arrows 3 A- 3 A in FIG. 2B indicating how a roughness of a cross-over conductive layer that is part of the electrical cross over allows connection to the electrically conductive layer of the top substrate;",
"FIG. 3B shows a cross-sectional view as seen along the cutting plane defined by the lines and arrows 3 B- 3 B in FIG. 2B indicating the position of a second upper cross-over conductor;",
"FIG. 4 shows a cross-sectional side view as seen along the cutting plane as defined by the lines and arrows 4 - 4 of FIG. 2B revealing that the electrical cross over has two layers: a dielectric layer and a conductive layer;",
"FIG. 5 is a top plan view of the display of FIGS. 2A and 2B showing how a flexible conductive member is electrically connected to the electrically conductive material on one of the ledges and to the electrical cross-over member on the other ledge;",
"FIG. 6 is a cross-sectional view as seen along the cutting plane defined by the lines and arrows 6 - 6 in FIG. 5 ;",
"FIG. 7 is a top plan view of electrical traces and, for example, row electrodes formed on a bottom substrate along with electrical traces of a component of an electrical cross-over member;",
"FIG. 8 is a top plan view of electrical traces and, for example, column electrodes formed on a top substrate;",
"FIG. 9 is a top plan view of the top substrate of FIG. 8 overlaying the bottom substrate of FIG. 7 ;",
"and FIG. 10 is a cross-sectional view as seen along the cutting plane defined by the lines and arrows 10 - 10 in FIG. 9 .",
"The figures are not drawn to scale.",
"DETAILED DESCRIPTION FIGS. 1A and 1B (Prior Art) illustrate a typical plastic liquid crystal display with unpatterned electrically conductive layers (not shown).",
"There are two substrates each with a conductive layer formed on them.",
"The conductive layers are separated by a thin liquid crystal layer (not shown).",
"The top substrate 10 and the bottom substrate 12 each have a small section of substrate or ledge 14 , 16 that is exposed and protrudes from the display for the purpose of electrical connection to the display.",
"The electrically conductive layers are on each of the ledges.",
"The top substrate 10 has the conductive layer facing down, while the bottom substrate 12 has the conductive layer facing up.",
"Once the display 18 is assembled each substrate has its ledge exposed and protruding from the display.",
"A display assembled in this fashion requires an interconnect facing down for the bottom substrate 12 and an interconnect facing up for the top substrate 10 or a single flex containing a via.",
"FIGS. 2A and 2B illustrate a plastic display with unpatterned electrically conductive layers and with the inventive technique of electrically connecting to the electrically conductive layer of only one substrate 20 .",
"There are two substrates each formed with a conductive layer.",
"The conductive layers are separated by a thin liquid crystal layer.",
"The top substrate 22 has no exposed section or ledge that protrudes from the display.",
"The bottom substrate 20 has two small sections or ledges 24 , 26 exposed that protrude from the display for the purpose of electrical connection to the display.",
"The bottom substrate 20 also has the electric cross-over member 28 that electrically connects to the top substrate.",
"The top substrate 22 has the conductive layer facing down, while the bottom substrate 20 has the conductive layer facing up.",
"Once the display 30 is assembled only the bottom substrate has two ledges exposed that protrude from the display, where one is for electrical connection 32 to the bottom substrate and the other is for electrical connection 34 to the top substrate.",
"Both a dielectric, electrically insulating layer 36 and an electrically conductive cross-over conductor layer 38 make up the electrical cross over member 28 .",
"The dielectric and electrically conductive material are coated on the substrate 20 and have a ledge 24 under the coating to create the cross over.",
"FIG. 3A illustrates a close-up of the electrical cross over member 28 .",
"The cross-over conductor 38 allows spacers 40 used in the display to fall into valleys 42 created by the rough surface.",
"Since the spacers 40 are trapped in valleys that are deeper than the diameter of the spacers a top electrically conductive layer 44 comes in electrical contact with peaks 43 of the cross-over conductor 38 .",
"The top electrically conductive layer 44 is coated on the top substrate 22 and a bottom electrically conductive layer 46 is coated over the bottom substrate 20 .",
"In all embodiments of the invention, techniques for applying the electrically conductive layers and the liquid crystal layer (e.g., coating and printing techniques) include those disclosed in U.S. Pat. No. 7,170,481, which is incorporated herein by reference in its entirety.",
"FIG. 3B illustrates a variation of the electrical cross-over member 28 .",
"The cross-over member 28 includes another upper cross-over conductor 38 but inverted from its orientation in FIG. 3A so that its flat upper surface is in electrical contact with the upper electrically conductive member 44 and its lower surface contacts the upper surface of the other cross-over conductor 38 .",
"Peaks of the upper cross-over conductor can engage valleys of the lower cross-over conductor and vice versa.",
"Liquid crystal material and spacers are present in the valleys of the upper cross-over conductor.",
"This prevents burnout of the electrically conductive material due otherwise to application of voltage at point contacts of the peaks of the cross-over conductor with the electrically conductive layer.",
"The upper surface of the upper cross-over conductor engages the upper electrically conductive layer 44 as a flat surface.",
"This same use of a second cross-over conductor can be used in the second embodiment shown in FIG. 10 except that the upper flat surface of the upper cross-over conductor would electrically contact the third electrically conductive layer.",
"FIG. 4 illustrates a side cross-sectional view of the electrical crossover member 28 .",
"The dielectric layer 36 prevents the top and bottom substrates from shorting together.",
"Next to the dielectric layer 36 and the cross-over conductor 38 is the electrooptical material (e.g., liquid crystal material) 48 .",
"All of the electrooptical material of this disclosure has the same characteristics and is dispersed in a polymeric matrix.",
"A suitable display is an electrooptical material forming a bistable display.",
"Examples of liquid crystal materials are cholesteric, nematic and smectic.",
"A specific display suitable for use in the present invention is a bistable cholesteric liquid crystal display.",
"As will be apparent to those of ordinary skill in the art in view of the instant disclosure, the liquid crystal material will preferably be present in the displays of the invention in the form of liquid crystalline layers comprised of a liquid crystal dispersion and, most preferably, a cholesteric droplet dispersion.",
"There are many different approaches to the formation of a layer of liquid crystal droplets, some of which have been used for cholesteric liquid crystals.",
"To form such a liquid crystal layer, the liquid crystal can be microencapsulated, formed into a layer of phase separated liquid crystal droplets, or formed into emulsified droplets of liquid crystal.",
"More specifically, one process suitable for forming liquid crystal layers for use in the invention is phase separation, which is basically a process that involves mixing the cholesteric liquid crystalline material with a pre-polymer solution then polymerizing the polymer under suitable conditions to form a dispersion of droplets in a polymer binder.",
"Polymerization and, hence, droplet formation, occurs after the material mixture has been coated onto the display.",
"There are basically three types of polymerization techniques that can be used depending on the polymer (or monomer): (1) thermally induced phase separation (TIPS);",
"(2) polymerization induced phase separation (PIPS);",
"and, (3) solvent induced phase separation (SIPS), for example as disclosed in U.S. Pat. No. 7,170,481.",
"A bistable display is one having at least two states that are stable in an absence of an electric field.",
"Examples of other electrooptical materials that can be used in an electrooptical display instead of liquid crystal material are electrophoretic or electrowetting materials.",
"In FIG. 4 , notice that the section of bottom substrate 20 that is exposed and protrudes from the display 30 for electrical connection to the top substrate 22 is also shown.",
"A display area of the display 30 is located where the upper and lower electrically conductive layers 44 , 46 overlap having the electrooptical material 48 disposed between them.",
"A bonding area is where the bottom electrically conductive layer 46 protrudes from the upper substrate 22 on ledge 26 and where the cross-over conductor 38 protrudes from the upper substrate on ledge 24 .",
"A cross-over region 29 is where the cross-over member 28 extends under the conductive layer, coated top substrate 22 .",
"FIGS. 5 and 6 illustrate how the display's conductive ledges 24 , 26 connect to a flexible electronic conductor (“flex”) 50 .",
"The flex has conductive pads 52 that are connected to the display's conductive ledges using a conductive adhesive or anisotropic conductive film 53 .",
"The conductive pads face toward the display away from the viewer in this figure.",
"The conductive pads have conductive traces 54 that connect to them on the flex 50 , allowing electrical connection to the display through the end of the flex.",
"The flex 50 is made up of conductive pads 52 , conductive traces 54 , and a flexible plastic film 56 .",
"Once the display is connected to the flex, the flex can be connected to a PCB containing LCD driver chips through the traces on the flex.",
"Other ways of bonding display electronics to the electrical traces in the bonding areas are encompassed by this invention and would be apparent to those skilled in the art in view of this disclosure.",
"Top substrate 10 is transparent as are the traces used on the top and bottom substrate.",
"The traces can be formed of transparent conductive material such as conductive polymer, carbon nanotubes or indium tin oxide (ITO).",
"Referring to a second embodiment of the invention, FIG. 7 illustrates the patterned conductive traces 60 formed on a top surface of a bottom substrate 62 of a patterned display that uses this invention.",
"This substrate 62 is electrically connected to the circled trace region at 64 .",
"The opposite top substrate 66 ( FIG. 8 ) is electrically connected to the patterned conductive traces in the circled region 68 .",
"FIG. 8 illustrates patterned conductive traces 70 formed on a bottom surface of the top substrate of a patterned display that uses this invention.",
"Top substrate 66 is transparent as are the traces used on the top and bottom substrate.",
"The traces can be formed of transparent conductive material such as conductive polymer, carbon nanotubes or indium tin oxide (ITO).",
"The upper substrate 66 is electrically connected to the traces on the bottom substrate at 68 ( FIG. 7 ).",
"Conductive traces 72 on the bottom substrate 62 electrically connect in the z direction (in and out of the paper in the top views) to the patterned conductive traces of the top substrate shown in the circled region 74 .",
"A layer of liquid crystal material is disposed between the layers of conductive traces formed on the bottom and top substrates, but is confined to the region bounded by the top substrate ( FIG. 8 ).",
"Row electrodes 76 , for example, are formed by the conductive traces 60 on the bottom substrate 62 while column electrodes 78 , for example, are formed by the conductive traces 70 on the top substrate 66 .",
"FIG. 9 illustrates the top and bottom substrates overlayed forming a patterned display 80 .",
"The region of crossing row and column electrodes is the display area 81 .",
"The region to the left of the top substrate comprised of only the bottom substrate is the bonding area (i.e., regions 68 and 64 ).",
"The region shown at 82 is a portion of a cross-over region having an electrical connection between electrically conductive layers formed on the top and bottom substrates in the z direction with the traces 72 from the bottom substrate in region 68 and traces 70 from the top substrate 66 in the region 74 .",
"As shown in FIG. 10 , the patterned conductive traces 72 for the bottom substrate 62 are shown electrically connected to the patterned conductive traces 70 on the top substrate 66 in regions 68 and 74 through a patterned cross-over conductor 84 with a roughened top surface that forms a topography of peaks 85 and valleys 86 .",
"This figure shows how liquid crystal 87 surrounds the patterned conductive traces 72 , 70 and fills in the valleys 86 of the cross-over conductor.",
"Notice that a dielectric layer is not required for the patterned conductor display.",
"The bonding areas 68 , 64 of the display 80 can be connected to flex as in the case of the unpatterned display of the first embodiment ( FIGS. 2A and 2B ), and the flex can be connected to a PCB containing LCD driver chips through the traces of the flex.",
"Other ways of bonding display electronics to the electrical traces in the bonding areas are encompassed by this invention and would be apparent to those skilled in the art in view of this disclosure.",
"The invention will now be described with regard to the following example which should not be interpreted so as to limit the invention.",
"EXAMPLE A flexible plastic LCD was constructed using a crossover member to electrically connect the top substrate to a trace on the bottom substrate.",
"A UV-curable dielectric material (DuPont 5018) was screen printed onto a 2 mil PET substrate gravure coated with Agfa S300 PEDOT mixed with 0.15% Silquest A-187 silane by volume.",
"The print was executed by traversing an 80-durometer rectangular squeegee positioned at 45° over a 105 mesh stainless steel screen.",
"The dielectric print was cured under an Electro-Lite UV lamp without the manufacturer's filter in place at 8.0 mW/cm 2 for two minutes.",
"A conductive carbon paste (DuPont 7102) was used to screen print a trace on top of the cured dielectric layer in the same manner using a 195 mesh polyester screen.",
"The carbon trace was cured in an oven for five minutes at a temperature of 130 C. Upon curing, no conductivity was measured between the carbon trace and the PEDOT beneath the dielectric layer.",
"The display was made using a second 2 mil PET substrate gravure coated with Agfa S300 PEDOT mixed with 0.15% Silquest A-187 silane by volume.",
"A PIPS mixture of liquid crystal with 4.0 μm spacers mixed in (2.5% by volume) was laminated between the two substrates.",
"The PIPS mixture of liquid crystal was applied as a fluid onto the lower electrically conductive layer and the carbon trace and then when the electrically conductive coated upper substrate was laminated onto it the liquid crystal and spacers flowed inside valleys of the carbon trace.",
"Alternatively, the PIPS mixture of liquid crystal fluid could be applied to the electrically conductive coated upper substrate.",
"The top substrate was laminated so it covered only part of the carbon trace, leaving the rest exposed for switching purposes.",
"A second trace was left exposed on the bottom substrate that had only PEDOT on it.",
"The display was cured under an Electro-Lite UV lamp at an intensity of 0.92 mW/cm 2 for 20 minutes.",
"Both traces were painted with conductive silver paint and a pulse of 40V, 30 ms, 33 Hz was applied to the exposed silver paint over the conductive carbon paste (top substrate electrically conductive layer) and to the exposed silver paint over the electrically conductive layer (bottom substrate electrically conductive layer).",
"Many modifications and variations of the invention will be apparent to those of ordinary skill in the art in light of the foregoing disclosure.",
"Therefore, it is to be understood that, within the scope of the appended claims, the invention can be practiced otherwise than has been specifically shown and described."
] |
FIELD OF THE INVENTION
[0001] The present invention relates to virtual reality and augmented reality imaging and visualization systems.
BACKGROUND
[0002] In order for a 3D display to produce a true sensation of depth, and more specifically, a simulated sensation of surface depth, it is desirable for each point in the display's visual field to generate the accommodative response corresponding to its virtual depth. If the accommodative response to a display point does not correspond to the virtual depth of that point, as determined by the binocular depth cues of convergence and stereopsis, the human eye may experience an accommodation conflict, resulting in unstable imaging, harmful eye strain, headaches, and, in the absence of accommodation information, almost a complete lack of surface depth. Referring to FIG. 1 , an augmented reality scenario ( 8 ) is depicted with views to the user of actual objects within the user's reality, such as landscaping items including a concrete stage object ( 1120 ) in a park setting, and also views of virtual objects added into the view to produce the “augmented” reality view; here a robot statue ( 1110 ) is shown virtually standing upon the stage object ( 1120 ), and a bee character ( 2 ) is shown flying in the airspace near the user's head. Preferably the augmented reality system is 3-D capable, in which case it provides the user with the perception that the statue ( 1110 ) is standing on the stage ( 1120 ), and that the bee character ( 2 ) is flying close to the user's head. This perception may be greatly enhanced by utilizing visual accommodation cues to the user's eye and brain that the virtual objects ( 2 , 1110 ) have different depths of focus, and that the depth of focus or focal radii for the robot statue ( 1110 ) is approximately the same as that for the stage ( 1120 ). Conventional stereoscopic 3-D simulation display systems, such as that depicted in FIG. 2 , typically have two displays ( 74 , 76 ), one for each eye, at a fixed radial focal distance ( 10 ). As stated above, this conventional technology misses many of the valuable cues utilized by the human eye and brain to detect and interpret depth in three dimensions, including the accommodation cue, which is associated with the eye's repositioning of the crystalline lens within the eye complex to reach a different depth of focus with the eye. There is a need for an accommodation accurate display system which takes into account the accommodation aspects of the human eye/brain image processing complex.
SUMMARY
[0003] One embodiment is directed to a three-dimensional image visualization system, comprising a selectively transparent projection device for projecting an image toward an eye of a viewer from a projection device position in space relative to the eye of the viewer, the projection device being capable of assuming a substantially transparent state when no image is projected; an occlusion mask device coupled to the projection device and configured to selectively block light traveling toward the eye from one or more positions opposite of the projection device from the eye of the viewer in an occluding pattern correlated with the image projected by the projection device; and a zone plate diffraction patterning device interposed between the eye of the viewer and the projection device and configured to cause light from the projection device to pass through a diffraction pattern having a selectable geometry as it travels to the eye and enter the eye with a simulated focal distance from the eye based at least in part upon the selectable geometry of the diffraction pattern. The system further may comprise a controller operatively coupled to the projection device, occlusion mask device, and the zone plate diffraction patterning device and configured to coordinate projection of the image and associated occluding pattern, as well as interposition of the diffraction pattern at the selectable geometry. The controller may comprise a microprocessor. The projection device may comprise a substantially planar transparent digital display substantially occupying a display plane. The display plane may be oriented substantially perpendicularly from a visual axis of the eye of the viewer. The substantially planar transparent digital display may comprise a liquid crystal display. The substantially planar transparent digital display may comprise an organic light emitting diode display. The projection device may be configured to project the image toward the eye in a collimated form such that the depth of focus for the eye of the viewer is an infinite depth of focus. The projection device may comprise a high-speed mini-projector coupled to a substrate-guided delay exit pupil expander device configured to expand the size of the image before delivery to the eye of the viewer. The mini-projector may be mounted substantially perpendicularly to a visual axis of the eye of the viewer, and wherein the substrate-guided delay exit pupil expander device is configured to receive the image from the mini-projector and deliver it to the zone plate diffraction patterning device and to the eye of the viewer in the expanded size with an orientation substantially aligned with the visual axis of the eye. The zone plate diffraction patterning device and projection device may comprise at least one common structure. The zone plate diffraction patterning device may be integrated into a waveguide, such that the projection device comprises a high-speed mini-projector coupled to the waveguide and configured pass the image through the diffraction pattern before the image exits the waveguide en route to the eye of the viewer. The mini-projector may be mounted substantially perpendicularly to a visual axis of the eye of the viewer, and the waveguide may be configured to receive the image from the mini-projector and deliver it to the eye of the viewer in an expanded size with an orientation substantially aligned with the visual axis of the eye. The occlusion mask device my comprise a display configured to either occlude or pass light at each of a plurality of portions of the display, depending upon a pertinent command to occlude or pass light at each portion. The occlusion mask device may comprise one or more liquid crystal displays. The zone plate diffraction patterning device may comprise a high-frequency binary display configured to either occlude or pass light at each of a plurality of portions of the display, depending upon a pertinent command to occlude or pass light at each portion. The zone plate diffraction patterning device may have a refresh rate of between about 500 Hz and about 2,000 Hz. The zone plate diffraction patterning device may have a refresh rate of about 720 Hz. The controller may be configured to operate the projection device and occlusion mask device at between about 30 and about 60 frames per second, and to operate the zone plate diffraction patterning device to digitally display up to about 12 different diffraction patterns for each frame of the projection device and occlusion mask device. The projection device, occlusion mask device, and the zone plate diffraction patterning device collectively may comprise an imaging module for a single eye of the viewer, and the system further may comprise a second imaging module for another eye of the viewer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 depicts an illustration of an augmented reality scenario with certain virtual reality objects, and certain actual reality objects viewed by a person.
[0005] FIG. 2 illustrates a conventional stereoscopy system to simulate three-dimensional imaging for the user.
[0006] FIGS. 3A and 3B illustrate aspects of an accommodation accurate display configuration.
[0007] FIGS. 4A-4C illustrate relationships between radius of curvature and focal radius.
[0008] FIGS. 5-6C illustrate aspects of diffraction gratings as applied to the subject configurations.
[0009] FIGS. 7A-7C illustrate three different focal mechanisms.
[0010] FIG. 7D illustrates a Fresnel zone plate.
[0011] FIGS. 8A-8C illustrate various aspects of diffraction system focusing issues.
[0012] FIG. 9 illustrates one embodiment of a waveguide with embedded diffraction grating.
[0013] FIG. 10 illustrates one embodiment of a waveguide with embedded diffraction grating designed to allow one mode to escape and the other modes to remain trapped in the waveguide.
[0014] FIGS. 11A-11B illustrate aspects of a diffractive imaging module embodiment.
[0015] FIGS. 12A-12B illustrate aspects of a diffractive imaging module embodiment.
[0016] FIGS. 13A-13B illustrate aspects of a diffractive imaging module embodiment.
DETAILED DESCRIPTION
[0017] Referring to FIGS. 3A and 3B , various aspects of an AAD system are depicted. Referring to FIG. 3A , a simple illustration shows that in the place of two conventional displays as in stereoscopy ( FIG. 2 ), two complex images, one for each eye, with various radial focal depths ( 12 ) for various aspects ( 14 ) of each image may be utilized to provide each eye with the perception of three dimensional depth layering within the perceived image.
[0018] Referring to FIG. 3B , we have determined that the typical human eye is able to interpret approximately 12 layers (layers L 1 -L 12 in FIG. 3 B—drawing element 16 ) of depth based upon radial distance. A near field limit ( 78 ) of about 0.25 meters is about the closest depth of focus; a far-field limit ( 80 ) of about 3 meters means that any item farther than about 3 meters from the human eye receives infinite focus. The layers of focus get more and more thin as one gets closer to the eye; in other words, the eye is able to perceive differences in focal distance that are quite small relatively close to the eye, and this effect dissipates as objects fall farther away from the eye, as shown in FIG. 3B . Element 82 illustrates that at an infinite object location, a depth of focus/dioptric spacing value is about ⅓ diopters. One other way of describing the import of FIG. 3B : there are about twelve focal planes between the eye of the user and infinity. These focal planes, and the data within the depicted relationships, may be utilized to position virtual elements within an augmented reality scenario for a user's viewing, because the human eye is contantly sweeping around to utilize the focal planes to perceive depth.
[0019] Referring to FIGS. 4A-4C , if K(R) is a dynamic parameter for curvature equal to 1/R, where R is the focal radius of an item relative to a surface, then with increasing radius (R 3 , to R 2 , up to R 1 ), you have decreasing K(R). The light field produced by a point has a spherical curvature, which is a function of how far away the point is from the eye of the user. This relationship may also be utilized for AAD systems.
[0020] Referring to FIG. 3 , a conventional diffraction grating ( 22 ) is shown, with light passing through the grating spacing ( 18 ) at an angle (theta— 20 ) which is related to the diffraction order (n), spatial frequency, and K factor, which equals 1/d, using the following equation: d*sin(theta)=n*wavelength (or alternatively substituting the K factor, sin(theta)=n*wavelength*K. FIGS. 6A-6C illustrate that with decreased spacing ( 18 , 28 , 30 ) in the diffraction pattern ( 22 , 24 , 26 ), the angle ( 20 , 32 , 34 ) becomes greater.
[0021] Referring to FIG. 5 , three different focusing mechanisms are depicted—refraction through a lens ( 36 ), reflection with a curved mirror ( 38 ), and diffraction with a Fresnel zone plate ( 40 ), also shown in FIG. 7D ( 40 ).
[0022] Referring to FIG. 8A , a simplified version of diffraction is shown to illustrate that an N=−1 mode could correspond to a virtual image; an N=+1 mode could correspond to a real image, and an N=0 mode could correspond to a focused-at-infinity image. These images could be confusing to the human eye and brain, and particularly problematic if all focused on-axis, as shown in FIG. 8B . Referring to FIG. 8C , an off-axis focus configuration may be utilized to allow for blocking of modes/images that are unwanted. For example, a collimated (r=infinity) image may be formed by the N=0 mode; a divergent virtual image may be formed by the N=−1 mode; and a convergent image may be formed by the N=+1 mode. The difference in spatial location of these modes/images and their trajectories allows for filtering out or separation to prevent the aforementioned problems associated with diffraction imaging, such as overlaying, ghosting, and “multiple exposure” perception effects.
[0023] Referring to FIG. 8 , a waveguide is shown having an embedded diffraction grating; such waveguides are available, for example, from suppliers such as BAE Systems PLC of London, U.K. and may be utilized to intake an image from the left of FIG. 9 as shown, pass the image through the embedded diffraction grating ( 44 ), and pass the resultant image out at an angle (in FIG. 9 , for example, through the side of the waveguide). Thus a dual use of redirection and diffraction may be achieved with such an element. Indeed, off-axis focal techniques, such as those described in reference to FIG. 8C , may be combined with diffraction waveguide elements such as that shown in FIG. 9 to result in a configuration such as that shown in FIG. 10 , wherein not only are redirection and diffraction accomplished, but also filtering, since in the depicted embodiment the geometry of the diffracting waveguide is such that the N=−1 mode (say the virtual image) is passed out of the waveguide and into the eye of the user, and the other two modes (N=0 and N=+1) are trapped inside of the waveguide by reflection.
[0024] Referring to FIGS. 11A-13C , the aforementioned concepts are put into play with various augmented reality display configurations.
[0025] Referring to FIG. 11A , an AAD system comprises an imaging module ( 46 , 48 ) in front of each eye ( 4 , 6 ) through which the user sees the world. FIG. 11B illustrates a larger view of the module ( 46 ) with its associated (coupled via the depicted electronic control leads; leads may also be wireless) controller ( 66 ), which may be a microprocessor, microcontroller, field programmable gate array (FPGA), application specific integrated circuit (ASIC), or the like. The controller preferably is coupled to a power supply and also an information exchange device, such as a wireless internet or Bluetooth adaptor, to allow for the exchange of information between the outside world and the controller ( 66 ). The system may be configured to operate at an image refresh rate, such as a rate between 30 and 60 frames per second. The controller may be configured to operate a high-refresh rate digital high resolution display ( 52 ), such as a ferro-liquid, bluephase, or bent-corr display, to display various zone plate geometries quickly in succession, pertinent to each of the 12 or so depth layers. For example, in an embodiment wherein 60 frames per second overall performance is desired, the zone plate display ( 52 ) may be operated at 12 times this, or 720 Hz, to be able to provide simulated accommodation to each of the 12 depth layers as shown in FIG. 3B . The occluding mask display ( 54 ) is configured to display a blacked out image geometrically corresponding to the image displayed before it on the transparent projector layer ( 56 )—blacked out to prevent light from the other side of the occluding mask display from bleeding through or interfering with display of a desired virtual or augmented image in the projector layer ( 56 ). Thus in an augmented reality configuration, as shown, light from the real background passes through the non-masked portions of the occlusion mask ( 54 ), though the transparent (i.e., not broadcasting a portion of an image) portions of the transparent projector layer ( 56 ), and into the zone plate layer ( 52 ) for accommodation treatment; images projected at the projecting layer ( 56 ) receive mask blocking from background light at the occlusion layer ( 54 ) and are projected forward into the zone plate layer ( 52 ) for accommodation treatment. The combination of these, or the associated perception of the augmented reality to the user, is very close to “true 3-D”.
[0026] FIGS. 12A-12B depict another embodiment wherein an imaging module ( 58 ) comprises high-resolution mini projector oriented at an angle approximately perpendicular to the visual axis of the eye; a waveguide comprising a substrate guided delay exit pupil expander device ( 70 ) magnifies and redirects the image from the small mini projector and into the zone plate layer ( 52 ); the occluding layer ( 54 ) provides similar masking functions to protect perception of the projected images from background lighting.
[0027] FIGS. 13A-13B depict another embodiment elements 52 and 70 are combined such that the zone plate and projecting layer are essentially housed within the same integrated module ( 72 ) which intakes a small image from the mini projector ( 68 ), redirects and magnifies it, and also diffracts it, for passage to the eye; the occluding layer ( 54 ) provides similar masking functions to protect perception of the projected images from background lighting.
[0028] Various exemplary embodiments of the invention are described herein. Reference is made to these examples in a non-limiting sense. They are provided to illustrate more broadly applicable aspects of the invention. Various changes may be made to the invention described and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process act(s) or step(s) to the objective(s), spirit or scope of the present invention. Further, as will be appreciated by those with skill in the art that each of the individual variations described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present inventions. All such modifications are intended to be within the scope of claims associated with this disclosure.
[0029] The invention includes methods that may be performed using the subject devices. The methods may comprise the act of providing such a suitable device. Such provision may be performed by the end user. In other words, the “providing” act merely requires the end user obtain, access, approach, position, set-up, activate, power-up or otherwise act to provide the requisite device in the subject method. Methods recited herein may be carried out in any order of the recited events which is logically possible, as well as in the recited order of events.
[0030] Exemplary aspects of the invention, together with details regarding material selection and manufacture have been set forth above. As for other details of the present invention, these may be appreciated in connection with the above-referenced patents and publications as well as generally known or appreciated by those with skill in the art. The same may hold true with respect to method-based aspects of the invention in terms of additional acts as commonly or logically employed.
[0031] In addition, though the invention has been described in reference to several examples optionally incorporating various features, the invention is not to be limited to that which is described or indicated as contemplated with respect to each variation of the invention. Various changes may be made to the invention described and equivalents (whether recited herein or not included for the sake of some brevity) may be substituted without departing from the true spirit and scope of the invention. In addition, where a range of values is provided, it is understood that every intervening value, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention.
[0032] Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in claims associated hereto, the singular forms “a,” “an,” “said,” and “the” include plural referents unless the specifically stated otherwise. In other words, use of the articles allow for “at least one” of the subject item in the description above as well as claims associated with this disclosure. It is further noted that such claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.
[0033] Without the use of such exclusive terminology, the term “comprising” in claims associated with this disclosure shall allow for the inclusion of any additional element—irrespective of whether a given number of elements are enumerated in such claims, or the addition of a feature could be regarded as transforming the nature of an element set forth in such claims. Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity.
[0034] The breadth of the present invention is not to be limited to the examples provided and/or the subject specification, but rather only by the scope of claim language associated with this disclosure. | A system may comprise a selectively transparent projection device for projecting an image toward an eye of a viewer from a projection device position in space relative to the eye of the viewer, the projection device being capable of assuming a substantially transparent state when no image is projected; an occlusion mask device coupled to the projection device and configured to selectively block light traveling toward the eye from one or more positions opposite of the projection device from the eye of the viewer in an occluding pattern correlated with the image projected by the projection device; and a zone plate diffraction patterning device interposed between the eye of the viewer and the projection device and configured to cause light from the projection device to pass through a diffraction pattern having a selectable geometry as it travels to the eye. | Briefly describe the main idea outlined in the provided context. | [
"FIELD OF THE INVENTION [0001] The present invention relates to virtual reality and augmented reality imaging and visualization systems.",
"BACKGROUND [0002] In order for a 3D display to produce a true sensation of depth, and more specifically, a simulated sensation of surface depth, it is desirable for each point in the display's visual field to generate the accommodative response corresponding to its virtual depth.",
"If the accommodative response to a display point does not correspond to the virtual depth of that point, as determined by the binocular depth cues of convergence and stereopsis, the human eye may experience an accommodation conflict, resulting in unstable imaging, harmful eye strain, headaches, and, in the absence of accommodation information, almost a complete lack of surface depth.",
"Referring to FIG. 1 , an augmented reality scenario ( 8 ) is depicted with views to the user of actual objects within the user's reality, such as landscaping items including a concrete stage object ( 1120 ) in a park setting, and also views of virtual objects added into the view to produce the “augmented”",
"reality view;",
"here a robot statue ( 1110 ) is shown virtually standing upon the stage object ( 1120 ), and a bee character ( 2 ) is shown flying in the airspace near the user's head.",
"Preferably the augmented reality system is 3-D capable, in which case it provides the user with the perception that the statue ( 1110 ) is standing on the stage ( 1120 ), and that the bee character ( 2 ) is flying close to the user's head.",
"This perception may be greatly enhanced by utilizing visual accommodation cues to the user's eye and brain that the virtual objects ( 2 , 1110 ) have different depths of focus, and that the depth of focus or focal radii for the robot statue ( 1110 ) is approximately the same as that for the stage ( 1120 ).",
"Conventional stereoscopic 3-D simulation display systems, such as that depicted in FIG. 2 , typically have two displays ( 74 , 76 ), one for each eye, at a fixed radial focal distance ( 10 ).",
"As stated above, this conventional technology misses many of the valuable cues utilized by the human eye and brain to detect and interpret depth in three dimensions, including the accommodation cue, which is associated with the eye's repositioning of the crystalline lens within the eye complex to reach a different depth of focus with the eye.",
"There is a need for an accommodation accurate display system which takes into account the accommodation aspects of the human eye/brain image processing complex.",
"SUMMARY [0003] One embodiment is directed to a three-dimensional image visualization system, comprising a selectively transparent projection device for projecting an image toward an eye of a viewer from a projection device position in space relative to the eye of the viewer, the projection device being capable of assuming a substantially transparent state when no image is projected;",
"an occlusion mask device coupled to the projection device and configured to selectively block light traveling toward the eye from one or more positions opposite of the projection device from the eye of the viewer in an occluding pattern correlated with the image projected by the projection device;",
"and a zone plate diffraction patterning device interposed between the eye of the viewer and the projection device and configured to cause light from the projection device to pass through a diffraction pattern having a selectable geometry as it travels to the eye and enter the eye with a simulated focal distance from the eye based at least in part upon the selectable geometry of the diffraction pattern.",
"The system further may comprise a controller operatively coupled to the projection device, occlusion mask device, and the zone plate diffraction patterning device and configured to coordinate projection of the image and associated occluding pattern, as well as interposition of the diffraction pattern at the selectable geometry.",
"The controller may comprise a microprocessor.",
"The projection device may comprise a substantially planar transparent digital display substantially occupying a display plane.",
"The display plane may be oriented substantially perpendicularly from a visual axis of the eye of the viewer.",
"The substantially planar transparent digital display may comprise a liquid crystal display.",
"The substantially planar transparent digital display may comprise an organic light emitting diode display.",
"The projection device may be configured to project the image toward the eye in a collimated form such that the depth of focus for the eye of the viewer is an infinite depth of focus.",
"The projection device may comprise a high-speed mini-projector coupled to a substrate-guided delay exit pupil expander device configured to expand the size of the image before delivery to the eye of the viewer.",
"The mini-projector may be mounted substantially perpendicularly to a visual axis of the eye of the viewer, and wherein the substrate-guided delay exit pupil expander device is configured to receive the image from the mini-projector and deliver it to the zone plate diffraction patterning device and to the eye of the viewer in the expanded size with an orientation substantially aligned with the visual axis of the eye.",
"The zone plate diffraction patterning device and projection device may comprise at least one common structure.",
"The zone plate diffraction patterning device may be integrated into a waveguide, such that the projection device comprises a high-speed mini-projector coupled to the waveguide and configured pass the image through the diffraction pattern before the image exits the waveguide en route to the eye of the viewer.",
"The mini-projector may be mounted substantially perpendicularly to a visual axis of the eye of the viewer, and the waveguide may be configured to receive the image from the mini-projector and deliver it to the eye of the viewer in an expanded size with an orientation substantially aligned with the visual axis of the eye.",
"The occlusion mask device my comprise a display configured to either occlude or pass light at each of a plurality of portions of the display, depending upon a pertinent command to occlude or pass light at each portion.",
"The occlusion mask device may comprise one or more liquid crystal displays.",
"The zone plate diffraction patterning device may comprise a high-frequency binary display configured to either occlude or pass light at each of a plurality of portions of the display, depending upon a pertinent command to occlude or pass light at each portion.",
"The zone plate diffraction patterning device may have a refresh rate of between about 500 Hz and about 2,000 Hz.",
"The zone plate diffraction patterning device may have a refresh rate of about 720 Hz.",
"The controller may be configured to operate the projection device and occlusion mask device at between about 30 and about 60 frames per second, and to operate the zone plate diffraction patterning device to digitally display up to about 12 different diffraction patterns for each frame of the projection device and occlusion mask device.",
"The projection device, occlusion mask device, and the zone plate diffraction patterning device collectively may comprise an imaging module for a single eye of the viewer, and the system further may comprise a second imaging module for another eye of the viewer.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0004] FIG. 1 depicts an illustration of an augmented reality scenario with certain virtual reality objects, and certain actual reality objects viewed by a person.",
"[0005] FIG. 2 illustrates a conventional stereoscopy system to simulate three-dimensional imaging for the user.",
"[0006] FIGS. 3A and 3B illustrate aspects of an accommodation accurate display configuration.",
"[0007] FIGS. 4A-4C illustrate relationships between radius of curvature and focal radius.",
"[0008] FIGS. 5-6C illustrate aspects of diffraction gratings as applied to the subject configurations.",
"[0009] FIGS. 7A-7C illustrate three different focal mechanisms.",
"[0010] FIG. 7D illustrates a Fresnel zone plate.",
"[0011] FIGS. 8A-8C illustrate various aspects of diffraction system focusing issues.",
"[0012] FIG. 9 illustrates one embodiment of a waveguide with embedded diffraction grating.",
"[0013] FIG. 10 illustrates one embodiment of a waveguide with embedded diffraction grating designed to allow one mode to escape and the other modes to remain trapped in the waveguide.",
"[0014] FIGS. 11A-11B illustrate aspects of a diffractive imaging module embodiment.",
"[0015] FIGS. 12A-12B illustrate aspects of a diffractive imaging module embodiment.",
"[0016] FIGS. 13A-13B illustrate aspects of a diffractive imaging module embodiment.",
"DETAILED DESCRIPTION [0017] Referring to FIGS. 3A and 3B , various aspects of an AAD system are depicted.",
"Referring to FIG. 3A , a simple illustration shows that in the place of two conventional displays as in stereoscopy ( FIG. 2 ), two complex images, one for each eye, with various radial focal depths ( 12 ) for various aspects ( 14 ) of each image may be utilized to provide each eye with the perception of three dimensional depth layering within the perceived image.",
"[0018] Referring to FIG. 3B , we have determined that the typical human eye is able to interpret approximately 12 layers (layers L 1 -L 12 in FIG. 3 B—drawing element 16 ) of depth based upon radial distance.",
"A near field limit ( 78 ) of about 0.25 meters is about the closest depth of focus;",
"a far-field limit ( 80 ) of about 3 meters means that any item farther than about 3 meters from the human eye receives infinite focus.",
"The layers of focus get more and more thin as one gets closer to the eye;",
"in other words, the eye is able to perceive differences in focal distance that are quite small relatively close to the eye, and this effect dissipates as objects fall farther away from the eye, as shown in FIG. 3B .",
"Element 82 illustrates that at an infinite object location, a depth of focus/dioptric spacing value is about ⅓ diopters.",
"One other way of describing the import of FIG. 3B : there are about twelve focal planes between the eye of the user and infinity.",
"These focal planes, and the data within the depicted relationships, may be utilized to position virtual elements within an augmented reality scenario for a user's viewing, because the human eye is contantly sweeping around to utilize the focal planes to perceive depth.",
"[0019] Referring to FIGS. 4A-4C , if K(R) is a dynamic parameter for curvature equal to 1/R, where R is the focal radius of an item relative to a surface, then with increasing radius (R 3 , to R 2 , up to R 1 ), you have decreasing K(R).",
"The light field produced by a point has a spherical curvature, which is a function of how far away the point is from the eye of the user.",
"This relationship may also be utilized for AAD systems.",
"[0020] Referring to FIG. 3 , a conventional diffraction grating ( 22 ) is shown, with light passing through the grating spacing ( 18 ) at an angle (theta— 20 ) which is related to the diffraction order (n), spatial frequency, and K factor, which equals 1/d, using the following equation: d*sin(theta)=n*wavelength (or alternatively substituting the K factor, sin(theta)=n*wavelength*K.",
"FIGS. 6A-6C illustrate that with decreased spacing ( 18 , 28 , 30 ) in the diffraction pattern ( 22 , 24 , 26 ), the angle ( 20 , 32 , 34 ) becomes greater.",
"[0021] Referring to FIG. 5 , three different focusing mechanisms are depicted—refraction through a lens ( 36 ), reflection with a curved mirror ( 38 ), and diffraction with a Fresnel zone plate ( 40 ), also shown in FIG. 7D ( 40 ).",
"[0022] Referring to FIG. 8A , a simplified version of diffraction is shown to illustrate that an N=−1 mode could correspond to a virtual image;",
"an N=+1 mode could correspond to a real image, and an N=0 mode could correspond to a focused-at-infinity image.",
"These images could be confusing to the human eye and brain, and particularly problematic if all focused on-axis, as shown in FIG. 8B .",
"Referring to FIG. 8C , an off-axis focus configuration may be utilized to allow for blocking of modes/images that are unwanted.",
"For example, a collimated (r=infinity) image may be formed by the N=0 mode;",
"a divergent virtual image may be formed by the N=−1 mode;",
"and a convergent image may be formed by the N=+1 mode.",
"The difference in spatial location of these modes/images and their trajectories allows for filtering out or separation to prevent the aforementioned problems associated with diffraction imaging, such as overlaying, ghosting, and “multiple exposure”",
"perception effects.",
"[0023] Referring to FIG. 8 , a waveguide is shown having an embedded diffraction grating;",
"such waveguides are available, for example, from suppliers such as BAE Systems PLC of London, U.K. and may be utilized to intake an image from the left of FIG. 9 as shown, pass the image through the embedded diffraction grating ( 44 ), and pass the resultant image out at an angle (in FIG. 9 , for example, through the side of the waveguide).",
"Thus a dual use of redirection and diffraction may be achieved with such an element.",
"Indeed, off-axis focal techniques, such as those described in reference to FIG. 8C , may be combined with diffraction waveguide elements such as that shown in FIG. 9 to result in a configuration such as that shown in FIG. 10 , wherein not only are redirection and diffraction accomplished, but also filtering, since in the depicted embodiment the geometry of the diffracting waveguide is such that the N=−1 mode (say the virtual image) is passed out of the waveguide and into the eye of the user, and the other two modes (N=0 and N=+1) are trapped inside of the waveguide by reflection.",
"[0024] Referring to FIGS. 11A-13C , the aforementioned concepts are put into play with various augmented reality display configurations.",
"[0025] Referring to FIG. 11A , an AAD system comprises an imaging module ( 46 , 48 ) in front of each eye ( 4 , 6 ) through which the user sees the world.",
"FIG. 11B illustrates a larger view of the module ( 46 ) with its associated (coupled via the depicted electronic control leads;",
"leads may also be wireless) controller ( 66 ), which may be a microprocessor, microcontroller, field programmable gate array (FPGA), application specific integrated circuit (ASIC), or the like.",
"The controller preferably is coupled to a power supply and also an information exchange device, such as a wireless internet or Bluetooth adaptor, to allow for the exchange of information between the outside world and the controller ( 66 ).",
"The system may be configured to operate at an image refresh rate, such as a rate between 30 and 60 frames per second.",
"The controller may be configured to operate a high-refresh rate digital high resolution display ( 52 ), such as a ferro-liquid, bluephase, or bent-corr display, to display various zone plate geometries quickly in succession, pertinent to each of the 12 or so depth layers.",
"For example, in an embodiment wherein 60 frames per second overall performance is desired, the zone plate display ( 52 ) may be operated at 12 times this, or 720 Hz, to be able to provide simulated accommodation to each of the 12 depth layers as shown in FIG. 3B .",
"The occluding mask display ( 54 ) is configured to display a blacked out image geometrically corresponding to the image displayed before it on the transparent projector layer ( 56 )—blacked out to prevent light from the other side of the occluding mask display from bleeding through or interfering with display of a desired virtual or augmented image in the projector layer ( 56 ).",
"Thus in an augmented reality configuration, as shown, light from the real background passes through the non-masked portions of the occlusion mask ( 54 ), though the transparent (i.e., not broadcasting a portion of an image) portions of the transparent projector layer ( 56 ), and into the zone plate layer ( 52 ) for accommodation treatment;",
"images projected at the projecting layer ( 56 ) receive mask blocking from background light at the occlusion layer ( 54 ) and are projected forward into the zone plate layer ( 52 ) for accommodation treatment.",
"The combination of these, or the associated perception of the augmented reality to the user, is very close to “true 3-D.”",
"[0026] FIGS. 12A-12B depict another embodiment wherein an imaging module ( 58 ) comprises high-resolution mini projector oriented at an angle approximately perpendicular to the visual axis of the eye;",
"a waveguide comprising a substrate guided delay exit pupil expander device ( 70 ) magnifies and redirects the image from the small mini projector and into the zone plate layer ( 52 );",
"the occluding layer ( 54 ) provides similar masking functions to protect perception of the projected images from background lighting.",
"[0027] FIGS. 13A-13B depict another embodiment elements 52 and 70 are combined such that the zone plate and projecting layer are essentially housed within the same integrated module ( 72 ) which intakes a small image from the mini projector ( 68 ), redirects and magnifies it, and also diffracts it, for passage to the eye;",
"the occluding layer ( 54 ) provides similar masking functions to protect perception of the projected images from background lighting.",
"[0028] Various exemplary embodiments of the invention are described herein.",
"Reference is made to these examples in a non-limiting sense.",
"They are provided to illustrate more broadly applicable aspects of the invention.",
"Various changes may be made to the invention described and equivalents may be substituted without departing from the true spirit and scope of the invention.",
"In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process act(s) or step(s) to the objective(s), spirit or scope of the present invention.",
"Further, as will be appreciated by those with skill in the art that each of the individual variations described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present inventions.",
"All such modifications are intended to be within the scope of claims associated with this disclosure.",
"[0029] The invention includes methods that may be performed using the subject devices.",
"The methods may comprise the act of providing such a suitable device.",
"Such provision may be performed by the end user.",
"In other words, the “providing”",
"act merely requires the end user obtain, access, approach, position, set-up, activate, power-up or otherwise act to provide the requisite device in the subject method.",
"Methods recited herein may be carried out in any order of the recited events which is logically possible, as well as in the recited order of events.",
"[0030] Exemplary aspects of the invention, together with details regarding material selection and manufacture have been set forth above.",
"As for other details of the present invention, these may be appreciated in connection with the above-referenced patents and publications as well as generally known or appreciated by those with skill in the art.",
"The same may hold true with respect to method-based aspects of the invention in terms of additional acts as commonly or logically employed.",
"[0031] In addition, though the invention has been described in reference to several examples optionally incorporating various features, the invention is not to be limited to that which is described or indicated as contemplated with respect to each variation of the invention.",
"Various changes may be made to the invention described and equivalents (whether recited herein or not included for the sake of some brevity) may be substituted without departing from the true spirit and scope of the invention.",
"In addition, where a range of values is provided, it is understood that every intervening value, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention.",
"[0032] Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein.",
"Reference to a singular item, includes the possibility that there are plural of the same items present.",
"More specifically, as used herein and in claims associated hereto, the singular forms “a,” “an,” “said,” and “the”",
"include plural referents unless the specifically stated otherwise.",
"In other words, use of the articles allow for “at least one”",
"of the subject item in the description above as well as claims associated with this disclosure.",
"It is further noted that such claims may be drafted to exclude any optional element.",
"As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only”",
"and the like in connection with the recitation of claim elements, or use of a “negative”",
"limitation.",
"[0033] Without the use of such exclusive terminology, the term “comprising”",
"in claims associated with this disclosure shall allow for the inclusion of any additional element—irrespective of whether a given number of elements are enumerated in such claims, or the addition of a feature could be regarded as transforming the nature of an element set forth in such claims.",
"Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity.",
"[0034] The breadth of the present invention is not to be limited to the examples provided and/or the subject specification, but rather only by the scope of claim language associated with this disclosure."
] |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority from provisional application Ser. No. 60/478,990, filed Jun. 17, 2003.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to electrochemical cells generating electrical energy by means of a chemical reaction. Electrolytic cells, for example of the lithium/silver vanadium oxide (Li/SVO) type, are typically constructed of one or more layers of anode, separator, and cathode. A screen or foil current collector is enclosed in the anode and cathode to transport electrons. An electrode assembly may be built by stacking multiple layers or plates on top of each other or by winding one or more long strips of the stacked layers around a mandrel. The electrode assembly is placed inside a case and immersed in an electrolyte, which transports ions.
[0004] One of the concerns in constructing an electrochemical cell is ensuring that the anode and cathode electrodes are properly aligned. This is not as great a problem is jellyroll electrode assemblies where the electrodes are of plates that are substantially longer than they are wide. The electrodes are then laid one on top of the other and spirally wound into the jellyroll configuration.
[0005] However, in an electrochemical cell having a multi-plate construction, electrode misalignment is a concern. Misalignment results in there being electrode plates that are not directly opposed by plates of an opposite polarity. In that respect, electrode plate misalignment detracts from the cell's discharge efficiency, as there will be active material that may not be fully reacted during electrochemical discharge. This is particularly likely to occur at the electrode edges.
[0006] The present invention prevents such misalignment by providing at least one of the electrode current collectors with projections emanating from its corners. These protrusions help to precisely position the current collector in a pressing fixture for contacting an active material to both sides thereof. That way, active material is contacted to each of the major faces of the current collector and is of a uniform thickness about its edges. Later, when the electrode plate is assembled into an electrochemical cell, such as of a multi-plate construction, the protrusions also serve to maintain strict alignment of the plate inside the casing.
[0007] Without protrusions according to the present invention, it is possible for the current collector to be positioned inside a pressing fixture with one portion of its edge too close to the fixture sidewall and another portion positioned too far away from the fixture. The result is that there is too much active material at the current collector edge spaced from the fixture sidewall and not enough at the other edge. This unbalanced active material contact can result in diminished discharge efficiency when the plate is incorporated into an electrochemical cell.
[0008] 2. Prior Art
[0009] U.S. Pat. No. 627,134 to McDougall and U.S. Pat. No. 1,600,083 to Webster relate to current collectors having apertured projections. The projections do not contact the casing sidewall to ensure proper alignment. Instead, they receive locking rods for maintaining alignment inside a battery. Also, the prior art projections are not capable of centering the current collector in a pressing fixture. For example, with a generally rectangular shaped current collector, the centering projections must emanate from the corners at about a 45° angle, or essentially centered between the two contiguous sides. That way, with the current collector positioned in a fixture having the protrusion nested in a fixture corner, the immediately adjacent current collector sides are spaced from the pressing fixture sidewall by a like distance. The prior art current collectors do not provide for this type of centering as their protrusions emanate from a current collector side adjacent to a corner. A side emanating protrusion provides for proper spacing along the current collector side having the protrusion, but not along the adjacent side.
[0010] An example of this is shown with the current collector 10 illustrated in FIG. 1. The current collector 10 comprises first and second major faces 12 and 14 extending to a surrounding perimeter edge formed by opposed right and left sides 16 and 18 extending to upper and lower sides 20 and 22 . The right and left sides 16 , 18 and the upper side 20 are straight while the lower side 22 is curved. The current collector 10 has an interior perforated region 24 . Spaced apart protrusions 26 and 28 emanate from the upper side 20 adjacent to the respective right and left sides 16 and 18 . Similarly, spaced apart protrusions 30 and 32 emanate from the curved side 22 adjacent to the respective right and left sides 16 and 18 . Having a protrusion only emanating from one side of a current collector, instead of a corner between adjacent sides, means that there is no structure for regulating the spacing of the other current collector side within a pressing fixture or a casing sidewall, as the case may be. In other words, protrusion 26 correctly spaced the upper side 20 from a fixture sidewall (not shown), but is incapable of regulating the distance between the fixture and the right side 16 of the current collector 10 . A similar problem exists with respect to protrusion 30 and side 16 and protrusions 28 and 32 and side 18 .
[0011] Thus, there is a need for a current collector design that enhances alignment in a pressing fixture so that a desired thickness of active material contacts both major current collector faces and the surrounding edge. Additionally, the current collector must provide for proper alignment with the opposite polarity electrode when it is incorporated into an electrode assembly housed inside a cell casing. The present current collector design provides both of these benefits.
SUMMARY OF THE INVENTION
[0012] The present invention is directed to a current collector design that ensures proper alignment of the current collector in both a pressing fixture for production of an electrode plate and later when the plate is incorporated into a electrode assembly. Providing the current collector with protrusions emanating from its corners does this, regardless whether the current collector is of a generally square shape having sides of substantially similar lengths or of a rectangular shape. In the latter case, the current collector can be significantly longer than it is wide as in a jellyroll electrode assembly, or not as in a prismatic cell design. In any event, the protrusions emanate from the corners centered between the sides. That way, they provide for spacing the current collector from the fixture sidewall a similar distance at the adjacent sides. This ensures a uniform thickness of active material contacted to the current collector at the sides. After the electrode plate has been built, the protrusions provide for properly aligning the electrode plate housed inside the casing.
[0013] The foregoing and additional advances and characterizing features of the present invention will become clearly apparent upon reading the ensuing description together with the included drawings wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [0014]FIG. 1 is a perspective view of an exemplary current collector 10 according to the prior art.
[0015] [0015]FIG. 2 is a side elevational view of a current collector 40 according to the present invention.
[0016] [0016]FIG. 3 is a plan view showing the current collector 40 of Fig. Is a pressing fixture 42 for forming an electrode plate.
[0017] [0017]FIG. 4 is a perspective view of a cell 100 comprising a casing 102 in a shadowed outline containing both anode and cathode plates with the anode plates connected to the case.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Referring now to the drawings, FIGS. 2 and 3 illustrate an exemplary current collector 40 according to the present invention positioned within a pressing fixture 42 . The current collector 40 is a conductive member, typically selected from such materials as nickel, aluminum, stainless steel (for example according to U.S. Pat. No. 5,114,811 to Frysz et al.), mild steel, titanium, tantalum, platinum, gold, and cobalt-alloys (U.S. Pat. Nos. 6,541,158 and 6,110,622, both to Frysz et al.). These patents are assigned to the assignee of the present invention and incorporated herein by reference.
[0019] With respect to the orientation shown in the drawings, the current collector 40 comprises first and second major faces (only face 44 is shown) extending to a surrounding perimeter edge. Opposed right and left sides 46 and 48 extending to and meeting with upper and lower sides 50 and 52 form the edge. The right and left sides 46 , 48 and the upper side 50 are generally planar or straight while the lower side 52 is curved. The current collector 40 has a solid frame 54 bordered by the sides and extending inwardly a relatively short distance to an interior perforated region 56 . The perforations are shown having the shape of diamonds, although virtually any opening shape is contemplated by the scope of the invention. This includes an expanded screen. Also, the current collector 40 need not be perforated at all, but instead, can be a solid member.
[0020] A first protrusion 58 emanates from the junction of the contiguous right and upper sides 46 and 50 . In FIG. 2, an imaginary projection of the right side 46 is depicted by dashed line 60 and an imaginary projection of the upper side 50 is depicted by dashed line 62 . The dashed lines 60 and 62 form a right angle. A portion 58 A of the protrusion 58 resides between the dashed line 60 aligned with the right side 46 and the protrusion perimeter. Similarly, a portion 58 B of the protrusion resides between the dashed line 62 aligned with the upper side 50 and the protrusion perimeter. The significance of this will be described in detail with respect to FIG. 2.
[0021] A second protrusion 64 emanates from the junction of the contiguous right and lower sides 46 and 52 . The dashed line 60 aligned with the right side 46 of the current collector passes through this projection, as does an imaginary projection of the curved lower side 52 depicted by the dashed line 66 . The angle between the dashed lines 60 and 66 is obtuse. A portion 64 A of the protrusion 64 resides between the dashed line 60 aligned with the right side 46 and the protrusion perimeter. Similarly, a portion 64 B of the protrusion resides between the dashed line 66 aligned with the curved bottom side 52 and the protrusion perimeter. The significance of this will be described in detail hereinafter.
[0022] The current collector 40 is also provided with a protrusion 68 at the junction of the contiguous left and upper sides 48 , 50 and a protrusion 70 at the junction of the contiguous left and bottom sides 48 , 52 . An imaginary projection of the left side 48 is depicted by dashed line 72 . In that respect, protrusion 68 includes a portion 68 A that resides between the dashed line 62 aligned with the upper side 50 and the protrusion perimeter. And, a portion 68 B of the protrusion 68 resides between the dashed line 72 aligned with the left side 48 and the protrusion perimeter. The other protrusion 70 has portions 70 A and 70 B residing between the imaginary line projections 66 and 72 of the respective lower and left sides 52 , 48 and its perimeter. Again, the significance of this will be described in detail hereinafter.
[0023] A tab 74 extending from the upper side 50 completes current collector 40 .
[0024] As shown in FIGS. 3, the current collector 40 is received in the pressing fixture 42 comprising a bottom wall 76 supporting upstanding right and left sidewalls 78 and 80 and upstanding upper and lower sidewalls 82 and 84 . The sidewalls meet each other at curved corners and surround an opening leading into the fixture. A gap 86 is provided in the upper sidewall 82 to receive the current collector tab 74 .
[0025] The fixture 42 is used to build an electrode plate containing the current collector 40 . This is done by first loading an electrode active material (not shown) therein. The active material is preferably in a granular form or a blank cut from a freestanding sheet and has a substantially uniform thickness such that its upper surface is spaced below the upper edge of the fixture sidewalls 78 , 80 , 82 and 84 . The current collector 40 is then moved into the fixture 42 lying on top of the active material. In this position, protrusion 58 nests into contact with the curved corner between the right and upper sidewalls 78 , 82 . Similarly, protrusion 68 nests into contact with the curved corner between the upper and left sidewalls 82 , 80 , protrusion 70 nests into contact with the curved corner between the left and bottom sidewalls 80 , 84 and protrusion 64 nests into contact with the curved corner between the bottom and left sidewalls 84 , 80 of the fixture 42 . The protrusions 58 , 64 , 68 and 70 are of substantially the same size, i.e., of a similar radius, to ensure that there is equal spacing between the current collector edges and the immediately adjacent fixture sidewalls. This means that the distance between the right current collector edge 46 and the fixture sidewall 78 is the same as the distance between the upper edge 50 and upper sidewall 82 , the left edge 48 and left sidewall 80 and between the lower edge 52 and the lower sidewall 84 . If desired, however, the protrusions can be of unequal radii.
[0026] With the current collector 40 so positioned in the fixture 42 , another charge of active material is provided on top of the current collector. This active material, current collector, active material sandwich is then subjected to a pressing force sufficient to contact the active material to the major current collector faces and locked thereon through the perforations 54 . A suitable pressing force is about 10 to 20 tons/in 2 for about 30 to 60 seconds. In that manner, the protrusions ensure that there is a uniform amount of active material about the entire periphery of the current collector. A suitable process for forming blanks of active material is described in U.S. Pat. Nos. 5,435,874 and 5,571,640, both to Takeuchi et al. U.S. Pat. Nos. 4,830,960 and 4,964,877, both to Keister et al. describe a method for making an electrode component using a pressing fixture. All of these patents are assigned to the assignee of the present invention and incorporated herein by reference.
[0027] The thusly-manufactured electrode component can be either a cathode plate for a primary or secondary cell, or an anode plate for a secondary cell.
[0028] [0028]FIG. 4 illustrates an electrochemical cell 100 incorporating the current collector 40 of the present invention. The electrode assembly for the cell has both anode and cathode plates with the anode plates comprising the current collector 40 and electrically connected to the casing 102 serving as the negative terminal in a case-negative cell desigm. The casing 102 is of mating first and second clamshell portions 104 and 106 as described in U.S. Pat. No. 6,613,474 to Frustaci et al., which is assigned to the assignee of the present invention and incorporated herein by reference. However, as those who are skilled in the art will realize, the present invention current collector 40 is useful with any casing design including prismatic, cylindrical, or button shapes. The casing 102 is of a conductive material, such as of stainless steel or titanium.
[0029] The casing is adapted for housing various types of electrochemical chemistries such as alkali metal/solid cathode or alkali metal/oxyhalide electrochemical cells of both the solid cathode and liquid cathode types. The electrochemical cell 100 illustrated in FIG. 4 is of the liquid electrolyte type comprising a cathode electrode having a body of solid cathode material in the form of plates 108 A and 108 B comprising cathode active material pressed together and bonded against a cathode current collectors 110 that are of a similar shape, but somewhat smaller in size than the current collector 40 described in FIGS. 1 to 3 and being used for the anode electrode. This is because the anode current collectors 40 contact the inner surface of the casing 102 in the case-negative design. The cathode current collectors 110 for plates 108 A and 108 B are provide with a U-shaped tab 110 A connecting between them. This type of construction is referred to as a butterfly current collector, and is described in U.S. Pat. No. 5,250,373 to Muffoletto et al., the disclosure of which is hereby incorporated by reference. The U-shaped tab 110 A of the cathode is then connected to a terminal (not shown) insulated from the casing by a glass-to-metal seal (not shown), as is well known by those skilled in the art. Other cathode current collector designs can also be used. The cathode active material is preferably comprised of a metal, a metal oxide, a mixed metal oxide, a metal sulfide or a carbonaceous material.
[0030] The cell 100 further includes an anode electrode comprised of anode active plates 112 A, 112 B and 112 C, preferably of lithium sheets pressed to the opposite sides of the present invention current collector 40 . The outermost anode plates 112 A and 112 C are only provided with lithium on their inner surfaces facing cathode plates 108 A and 108 B, respectively. The anode current collector 40 is fabricated from a thin sheet of metal such as of nickel. The anode plates are in operative contact with the cathode plates through a thin sheet of separator material 114 . The separator divides the cathode and anode plates to prevent shorting by direct physical contact between the electrode plates while allowing ions to move between the plates.
[0031] The anode current collector tabs can be an individual piece attached to the case wall or, alternatively, they can be in the form of a U-shaped member connecting between two anode current collectors 40 . In cell 100 , anode plate 112 A has its current collector 40 provided with a tab having a portion 116 A planar therewith and a bent portion 116 B that is contacted to the casing 102 , such as by welding. Anode plates 112 B and 112 C are provide with a U-shaped tab 118 connecting between them. The mid-point or apex of the U-shaped tab 118 is joined to the tab portion 116 B, preferably by welding. The anode tabs are made of the same material as the current collector, preferably nickel, however, other materials also may be satisfactory.
[0032] By way of example, in an illustrative primary cell, the active material of the cathode body is a silver vanadium oxide cathode material as described in U.S. Pat. Nos. 4,310,609 and 4,391,729 or copper silver vanadium oxide as described in U.S. Pat. Nos. 5,472,810 and 5,516,340, all assigned to the assignee of the present invention, the disclosures of which are hereby incorporated by reference. The cathode current collectors 110 can be titanium, the cathode terminal lead can be molybdenum, and the separators 114 can be of polypropylene. The activating electrolyte can be a 1.0 M to 1.4 M solution of LiAsF 6 or LiPF 6 in a 50:50 mixture of, by volume, 1,2-dimethoxyethene and propylene carbonate. The glass seal can be of TA-23 Hermetic sealing glass, while the casing can be of stainless steel.
[0033] This electrochemical system is of a primary cell type. However, those skilled in the art will readily recognize that the casing of the present invention is readily adopted to house both primary electrochemical systems of either a solid cathode or liquid catholyte type, or a secondary cell such as a lithium ion cell having a carbonaceous negative electrode and lithium cobalt oxide positive electrode.
[0034] In the secondary electrochemical cell, the anode or negative electrode comprises an anode material capable of intercalating and de-intercalating the anode active material, such as the preferred alkali metal lithium. A carbonaceous negative electrode comprising any of the various forms of carbon (e.g., coke, graphite, acetylene black, carbon black, glass carbon, “hairy carbon” etc.), which are capable of reversibly retaining the lithium species, is preferred for the anode material. A “hairy carbon” material is particularly preferred due to its relatively high lithium-retention capacity. “Hairy carbon” is a material described in U.S. Pat. No. 5,443,928 to Takeuchi et al., which is assigned to the assignee of the present invention and incorporated herein by reference. Graphite is another preferred material. Regardless of the form of the carbon, fibers of the carbonaceous material are particularly advantageous because they have excellent mechanical properties that permit them to be fabricated into rigid electrodes capable of withstanding degradation during repeated charge/discharge cycling. Moreover, the high surface area of carbon fibers allows for rapid charge/discharge rates.
[0035] Also in secondary systems, the positive electrode preferably comprises a lithiated material that is stable in air and readily handled. Examples of such air-stable lithiated cathode active materials include oxides, sulfides, selenides, and tellurides of such metals as vanadium, titanium, chromium, copper, molybdenum, niobium, iron, nickel, cobalt and manganese. The more preferred oxides include LiNiO 2 , LiMn 2 O 4 , LiCoO 2 , LiCo 0.92 Sn 0.08 O 2 and LiCo 1−x Ni x O 2 .
[0036] An electrolyte is also required to activate the anode/cathode combination in the secondary system. The composition of the electrolyte depends on the materials of construction of the anode and the cathode as well as the product application for the cell. A preferred electrolyte for a lithium ion secondary cell has a lithium salt dissolved in a solvent system of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and propylene carbonate.
[0037] The current collector of the present invention can also be employed in a cell having a case-positive electrical configuration. In particular, replacing lithium anode elements with cathode plates provides a case-positive electrical configuration. Accordingly, cathode plates would be replaced by lithium anode plates, sandwiched together and against the current collector of the present invention serving as an anode current collector that, in turn, is connected to the terminal lead and insulated from the casing by the glass-to-metal seal. In all other respects, the anode current collector in the case-positive configuration is similar to that previously described with respect to cell 100 having the case-negative configuration.
[0038] The present invention may also be used with acid or alkaline-based batteries.
[0039] Now, it is therefore apparent that the present invention accomplishes its intended objects. While embodiments of the present invention have been described in detail, that is for the purpose of illustration, not limitation. | A current collector for en electrode of an electrochemical cell is described. The current collector has a peripheral edge between first and second major faces with the edge comprising at least a first side contiguous with a second side angled with respect to each other. A protrusion extends outwardly from the junction of the first and second sides. This protrusion helps to precisely position the current collector in a pressing fixture for contacting an active material to both sides thereof. That way, active material is contacted to each of the major faces of the current collector and is of a uniform thickness about its edges. Later, when the resulting electrode plate is assembled into an electrochemical cell, such as of a multi-plate construction, the protrusion also serves to maintain strict alignment of the plate inside the casing. | Summarize the patent information, clearly outlining the technical challenges and proposed solutions. | [
"CROSS-REFERENCE TO RELATED APPLICATION [0001] The present application claims priority from provisional application Ser.",
"No. 60/478,990, filed Jun. 17, 2003.",
"BACKGROUND OF THE INVENTION [0002] 1.",
"Field of the Invention [0003] The present invention relates to electrochemical cells generating electrical energy by means of a chemical reaction.",
"Electrolytic cells, for example of the lithium/silver vanadium oxide (Li/SVO) type, are typically constructed of one or more layers of anode, separator, and cathode.",
"A screen or foil current collector is enclosed in the anode and cathode to transport electrons.",
"An electrode assembly may be built by stacking multiple layers or plates on top of each other or by winding one or more long strips of the stacked layers around a mandrel.",
"The electrode assembly is placed inside a case and immersed in an electrolyte, which transports ions.",
"[0004] One of the concerns in constructing an electrochemical cell is ensuring that the anode and cathode electrodes are properly aligned.",
"This is not as great a problem is jellyroll electrode assemblies where the electrodes are of plates that are substantially longer than they are wide.",
"The electrodes are then laid one on top of the other and spirally wound into the jellyroll configuration.",
"[0005] However, in an electrochemical cell having a multi-plate construction, electrode misalignment is a concern.",
"Misalignment results in there being electrode plates that are not directly opposed by plates of an opposite polarity.",
"In that respect, electrode plate misalignment detracts from the cell's discharge efficiency, as there will be active material that may not be fully reacted during electrochemical discharge.",
"This is particularly likely to occur at the electrode edges.",
"[0006] The present invention prevents such misalignment by providing at least one of the electrode current collectors with projections emanating from its corners.",
"These protrusions help to precisely position the current collector in a pressing fixture for contacting an active material to both sides thereof.",
"That way, active material is contacted to each of the major faces of the current collector and is of a uniform thickness about its edges.",
"Later, when the electrode plate is assembled into an electrochemical cell, such as of a multi-plate construction, the protrusions also serve to maintain strict alignment of the plate inside the casing.",
"[0007] Without protrusions according to the present invention, it is possible for the current collector to be positioned inside a pressing fixture with one portion of its edge too close to the fixture sidewall and another portion positioned too far away from the fixture.",
"The result is that there is too much active material at the current collector edge spaced from the fixture sidewall and not enough at the other edge.",
"This unbalanced active material contact can result in diminished discharge efficiency when the plate is incorporated into an electrochemical cell.",
"[0008] 2.",
"Prior Art [0009] U.S. Pat. No. 627,134 to McDougall and U.S. Pat. No. 1,600,083 to Webster relate to current collectors having apertured projections.",
"The projections do not contact the casing sidewall to ensure proper alignment.",
"Instead, they receive locking rods for maintaining alignment inside a battery.",
"Also, the prior art projections are not capable of centering the current collector in a pressing fixture.",
"For example, with a generally rectangular shaped current collector, the centering projections must emanate from the corners at about a 45° angle, or essentially centered between the two contiguous sides.",
"That way, with the current collector positioned in a fixture having the protrusion nested in a fixture corner, the immediately adjacent current collector sides are spaced from the pressing fixture sidewall by a like distance.",
"The prior art current collectors do not provide for this type of centering as their protrusions emanate from a current collector side adjacent to a corner.",
"A side emanating protrusion provides for proper spacing along the current collector side having the protrusion, but not along the adjacent side.",
"[0010] An example of this is shown with the current collector 10 illustrated in FIG. 1. The current collector 10 comprises first and second major faces 12 and 14 extending to a surrounding perimeter edge formed by opposed right and left sides 16 and 18 extending to upper and lower sides 20 and 22 .",
"The right and left sides 16 , 18 and the upper side 20 are straight while the lower side 22 is curved.",
"The current collector 10 has an interior perforated region 24 .",
"Spaced apart protrusions 26 and 28 emanate from the upper side 20 adjacent to the respective right and left sides 16 and 18 .",
"Similarly, spaced apart protrusions 30 and 32 emanate from the curved side 22 adjacent to the respective right and left sides 16 and 18 .",
"Having a protrusion only emanating from one side of a current collector, instead of a corner between adjacent sides, means that there is no structure for regulating the spacing of the other current collector side within a pressing fixture or a casing sidewall, as the case may be.",
"In other words, protrusion 26 correctly spaced the upper side 20 from a fixture sidewall (not shown), but is incapable of regulating the distance between the fixture and the right side 16 of the current collector 10 .",
"A similar problem exists with respect to protrusion 30 and side 16 and protrusions 28 and 32 and side 18 .",
"[0011] Thus, there is a need for a current collector design that enhances alignment in a pressing fixture so that a desired thickness of active material contacts both major current collector faces and the surrounding edge.",
"Additionally, the current collector must provide for proper alignment with the opposite polarity electrode when it is incorporated into an electrode assembly housed inside a cell casing.",
"The present current collector design provides both of these benefits.",
"SUMMARY OF THE INVENTION [0012] The present invention is directed to a current collector design that ensures proper alignment of the current collector in both a pressing fixture for production of an electrode plate and later when the plate is incorporated into a electrode assembly.",
"Providing the current collector with protrusions emanating from its corners does this, regardless whether the current collector is of a generally square shape having sides of substantially similar lengths or of a rectangular shape.",
"In the latter case, the current collector can be significantly longer than it is wide as in a jellyroll electrode assembly, or not as in a prismatic cell design.",
"In any event, the protrusions emanate from the corners centered between the sides.",
"That way, they provide for spacing the current collector from the fixture sidewall a similar distance at the adjacent sides.",
"This ensures a uniform thickness of active material contacted to the current collector at the sides.",
"After the electrode plate has been built, the protrusions provide for properly aligning the electrode plate housed inside the casing.",
"[0013] The foregoing and additional advances and characterizing features of the present invention will become clearly apparent upon reading the ensuing description together with the included drawings wherein: BRIEF DESCRIPTION OF THE DRAWINGS [0014] [0014 ]FIG. 1 is a perspective view of an exemplary current collector 10 according to the prior art.",
"[0015] [0015 ]FIG. 2 is a side elevational view of a current collector 40 according to the present invention.",
"[0016] [0016 ]FIG. 3 is a plan view showing the current collector 40 of Fig.",
"Is a pressing fixture 42 for forming an electrode plate.",
"[0017] [0017 ]FIG. 4 is a perspective view of a cell 100 comprising a casing 102 in a shadowed outline containing both anode and cathode plates with the anode plates connected to the case.",
"DETAILED DESCRIPTION OF THE INVENTION [0018] Referring now to the drawings, FIGS. 2 and 3 illustrate an exemplary current collector 40 according to the present invention positioned within a pressing fixture 42 .",
"The current collector 40 is a conductive member, typically selected from such materials as nickel, aluminum, stainless steel (for example according to U.S. Pat. No. 5,114,811 to Frysz et al.), mild steel, titanium, tantalum, platinum, gold, and cobalt-alloys (U.S. Pat. Nos. 6,541,158 and 6,110,622, both to Frysz et al.).",
"These patents are assigned to the assignee of the present invention and incorporated herein by reference.",
"[0019] With respect to the orientation shown in the drawings, the current collector 40 comprises first and second major faces (only face 44 is shown) extending to a surrounding perimeter edge.",
"Opposed right and left sides 46 and 48 extending to and meeting with upper and lower sides 50 and 52 form the edge.",
"The right and left sides 46 , 48 and the upper side 50 are generally planar or straight while the lower side 52 is curved.",
"The current collector 40 has a solid frame 54 bordered by the sides and extending inwardly a relatively short distance to an interior perforated region 56 .",
"The perforations are shown having the shape of diamonds, although virtually any opening shape is contemplated by the scope of the invention.",
"This includes an expanded screen.",
"Also, the current collector 40 need not be perforated at all, but instead, can be a solid member.",
"[0020] A first protrusion 58 emanates from the junction of the contiguous right and upper sides 46 and 50 .",
"In FIG. 2, an imaginary projection of the right side 46 is depicted by dashed line 60 and an imaginary projection of the upper side 50 is depicted by dashed line 62 .",
"The dashed lines 60 and 62 form a right angle.",
"A portion 58 A of the protrusion 58 resides between the dashed line 60 aligned with the right side 46 and the protrusion perimeter.",
"Similarly, a portion 58 B of the protrusion resides between the dashed line 62 aligned with the upper side 50 and the protrusion perimeter.",
"The significance of this will be described in detail with respect to FIG. 2. [0021] A second protrusion 64 emanates from the junction of the contiguous right and lower sides 46 and 52 .",
"The dashed line 60 aligned with the right side 46 of the current collector passes through this projection, as does an imaginary projection of the curved lower side 52 depicted by the dashed line 66 .",
"The angle between the dashed lines 60 and 66 is obtuse.",
"A portion 64 A of the protrusion 64 resides between the dashed line 60 aligned with the right side 46 and the protrusion perimeter.",
"Similarly, a portion 64 B of the protrusion resides between the dashed line 66 aligned with the curved bottom side 52 and the protrusion perimeter.",
"The significance of this will be described in detail hereinafter.",
"[0022] The current collector 40 is also provided with a protrusion 68 at the junction of the contiguous left and upper sides 48 , 50 and a protrusion 70 at the junction of the contiguous left and bottom sides 48 , 52 .",
"An imaginary projection of the left side 48 is depicted by dashed line 72 .",
"In that respect, protrusion 68 includes a portion 68 A that resides between the dashed line 62 aligned with the upper side 50 and the protrusion perimeter.",
"And, a portion 68 B of the protrusion 68 resides between the dashed line 72 aligned with the left side 48 and the protrusion perimeter.",
"The other protrusion 70 has portions 70 A and 70 B residing between the imaginary line projections 66 and 72 of the respective lower and left sides 52 , 48 and its perimeter.",
"Again, the significance of this will be described in detail hereinafter.",
"[0023] A tab 74 extending from the upper side 50 completes current collector 40 .",
"[0024] As shown in FIGS. 3, the current collector 40 is received in the pressing fixture 42 comprising a bottom wall 76 supporting upstanding right and left sidewalls 78 and 80 and upstanding upper and lower sidewalls 82 and 84 .",
"The sidewalls meet each other at curved corners and surround an opening leading into the fixture.",
"A gap 86 is provided in the upper sidewall 82 to receive the current collector tab 74 .",
"[0025] The fixture 42 is used to build an electrode plate containing the current collector 40 .",
"This is done by first loading an electrode active material (not shown) therein.",
"The active material is preferably in a granular form or a blank cut from a freestanding sheet and has a substantially uniform thickness such that its upper surface is spaced below the upper edge of the fixture sidewalls 78 , 80 , 82 and 84 .",
"The current collector 40 is then moved into the fixture 42 lying on top of the active material.",
"In this position, protrusion 58 nests into contact with the curved corner between the right and upper sidewalls 78 , 82 .",
"Similarly, protrusion 68 nests into contact with the curved corner between the upper and left sidewalls 82 , 80 , protrusion 70 nests into contact with the curved corner between the left and bottom sidewalls 80 , 84 and protrusion 64 nests into contact with the curved corner between the bottom and left sidewalls 84 , 80 of the fixture 42 .",
"The protrusions 58 , 64 , 68 and 70 are of substantially the same size, i.e., of a similar radius, to ensure that there is equal spacing between the current collector edges and the immediately adjacent fixture sidewalls.",
"This means that the distance between the right current collector edge 46 and the fixture sidewall 78 is the same as the distance between the upper edge 50 and upper sidewall 82 , the left edge 48 and left sidewall 80 and between the lower edge 52 and the lower sidewall 84 .",
"If desired, however, the protrusions can be of unequal radii.",
"[0026] With the current collector 40 so positioned in the fixture 42 , another charge of active material is provided on top of the current collector.",
"This active material, current collector, active material sandwich is then subjected to a pressing force sufficient to contact the active material to the major current collector faces and locked thereon through the perforations 54 .",
"A suitable pressing force is about 10 to 20 tons/in 2 for about 30 to 60 seconds.",
"In that manner, the protrusions ensure that there is a uniform amount of active material about the entire periphery of the current collector.",
"A suitable process for forming blanks of active material is described in U.S. Pat. Nos. 5,435,874 and 5,571,640, both to Takeuchi et al.",
"U.S. Pat. Nos. 4,830,960 and 4,964,877, both to Keister et al.",
"describe a method for making an electrode component using a pressing fixture.",
"All of these patents are assigned to the assignee of the present invention and incorporated herein by reference.",
"[0027] The thusly-manufactured electrode component can be either a cathode plate for a primary or secondary cell, or an anode plate for a secondary cell.",
"[0028] [0028 ]FIG. 4 illustrates an electrochemical cell 100 incorporating the current collector 40 of the present invention.",
"The electrode assembly for the cell has both anode and cathode plates with the anode plates comprising the current collector 40 and electrically connected to the casing 102 serving as the negative terminal in a case-negative cell desigm.",
"The casing 102 is of mating first and second clamshell portions 104 and 106 as described in U.S. Pat. No. 6,613,474 to Frustaci et al.",
", which is assigned to the assignee of the present invention and incorporated herein by reference.",
"However, as those who are skilled in the art will realize, the present invention current collector 40 is useful with any casing design including prismatic, cylindrical, or button shapes.",
"The casing 102 is of a conductive material, such as of stainless steel or titanium.",
"[0029] The casing is adapted for housing various types of electrochemical chemistries such as alkali metal/solid cathode or alkali metal/oxyhalide electrochemical cells of both the solid cathode and liquid cathode types.",
"The electrochemical cell 100 illustrated in FIG. 4 is of the liquid electrolyte type comprising a cathode electrode having a body of solid cathode material in the form of plates 108 A and 108 B comprising cathode active material pressed together and bonded against a cathode current collectors 110 that are of a similar shape, but somewhat smaller in size than the current collector 40 described in FIGS. 1 to 3 and being used for the anode electrode.",
"This is because the anode current collectors 40 contact the inner surface of the casing 102 in the case-negative design.",
"The cathode current collectors 110 for plates 108 A and 108 B are provide with a U-shaped tab 110 A connecting between them.",
"This type of construction is referred to as a butterfly current collector, and is described in U.S. Pat. No. 5,250,373 to Muffoletto et al.",
", the disclosure of which is hereby incorporated by reference.",
"The U-shaped tab 110 A of the cathode is then connected to a terminal (not shown) insulated from the casing by a glass-to-metal seal (not shown), as is well known by those skilled in the art.",
"Other cathode current collector designs can also be used.",
"The cathode active material is preferably comprised of a metal, a metal oxide, a mixed metal oxide, a metal sulfide or a carbonaceous material.",
"[0030] The cell 100 further includes an anode electrode comprised of anode active plates 112 A, 112 B and 112 C, preferably of lithium sheets pressed to the opposite sides of the present invention current collector 40 .",
"The outermost anode plates 112 A and 112 C are only provided with lithium on their inner surfaces facing cathode plates 108 A and 108 B, respectively.",
"The anode current collector 40 is fabricated from a thin sheet of metal such as of nickel.",
"The anode plates are in operative contact with the cathode plates through a thin sheet of separator material 114 .",
"The separator divides the cathode and anode plates to prevent shorting by direct physical contact between the electrode plates while allowing ions to move between the plates.",
"[0031] The anode current collector tabs can be an individual piece attached to the case wall or, alternatively, they can be in the form of a U-shaped member connecting between two anode current collectors 40 .",
"In cell 100 , anode plate 112 A has its current collector 40 provided with a tab having a portion 116 A planar therewith and a bent portion 116 B that is contacted to the casing 102 , such as by welding.",
"Anode plates 112 B and 112 C are provide with a U-shaped tab 118 connecting between them.",
"The mid-point or apex of the U-shaped tab 118 is joined to the tab portion 116 B, preferably by welding.",
"The anode tabs are made of the same material as the current collector, preferably nickel, however, other materials also may be satisfactory.",
"[0032] By way of example, in an illustrative primary cell, the active material of the cathode body is a silver vanadium oxide cathode material as described in U.S. Pat. Nos. 4,310,609 and 4,391,729 or copper silver vanadium oxide as described in U.S. Pat. Nos. 5,472,810 and 5,516,340, all assigned to the assignee of the present invention, the disclosures of which are hereby incorporated by reference.",
"The cathode current collectors 110 can be titanium, the cathode terminal lead can be molybdenum, and the separators 114 can be of polypropylene.",
"The activating electrolyte can be a 1.0 M to 1.4 M solution of LiAsF 6 or LiPF 6 in a 50:50 mixture of, by volume, 1,2-dimethoxyethene and propylene carbonate.",
"The glass seal can be of TA-23 Hermetic sealing glass, while the casing can be of stainless steel.",
"[0033] This electrochemical system is of a primary cell type.",
"However, those skilled in the art will readily recognize that the casing of the present invention is readily adopted to house both primary electrochemical systems of either a solid cathode or liquid catholyte type, or a secondary cell such as a lithium ion cell having a carbonaceous negative electrode and lithium cobalt oxide positive electrode.",
"[0034] In the secondary electrochemical cell, the anode or negative electrode comprises an anode material capable of intercalating and de-intercalating the anode active material, such as the preferred alkali metal lithium.",
"A carbonaceous negative electrode comprising any of the various forms of carbon (e.g., coke, graphite, acetylene black, carbon black, glass carbon, “hairy carbon”",
"etc.), which are capable of reversibly retaining the lithium species, is preferred for the anode material.",
"A “hairy carbon”",
"material is particularly preferred due to its relatively high lithium-retention capacity.",
"“Hairy carbon”",
"is a material described in U.S. Pat. No. 5,443,928 to Takeuchi et al.",
", which is assigned to the assignee of the present invention and incorporated herein by reference.",
"Graphite is another preferred material.",
"Regardless of the form of the carbon, fibers of the carbonaceous material are particularly advantageous because they have excellent mechanical properties that permit them to be fabricated into rigid electrodes capable of withstanding degradation during repeated charge/discharge cycling.",
"Moreover, the high surface area of carbon fibers allows for rapid charge/discharge rates.",
"[0035] Also in secondary systems, the positive electrode preferably comprises a lithiated material that is stable in air and readily handled.",
"Examples of such air-stable lithiated cathode active materials include oxides, sulfides, selenides, and tellurides of such metals as vanadium, titanium, chromium, copper, molybdenum, niobium, iron, nickel, cobalt and manganese.",
"The more preferred oxides include LiNiO 2 , LiMn 2 O 4 , LiCoO 2 , LiCo 0.92 Sn 0.08 O 2 and LiCo 1−x Ni x O 2 .",
"[0036] An electrolyte is also required to activate the anode/cathode combination in the secondary system.",
"The composition of the electrolyte depends on the materials of construction of the anode and the cathode as well as the product application for the cell.",
"A preferred electrolyte for a lithium ion secondary cell has a lithium salt dissolved in a solvent system of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and propylene carbonate.",
"[0037] The current collector of the present invention can also be employed in a cell having a case-positive electrical configuration.",
"In particular, replacing lithium anode elements with cathode plates provides a case-positive electrical configuration.",
"Accordingly, cathode plates would be replaced by lithium anode plates, sandwiched together and against the current collector of the present invention serving as an anode current collector that, in turn, is connected to the terminal lead and insulated from the casing by the glass-to-metal seal.",
"In all other respects, the anode current collector in the case-positive configuration is similar to that previously described with respect to cell 100 having the case-negative configuration.",
"[0038] The present invention may also be used with acid or alkaline-based batteries.",
"[0039] Now, it is therefore apparent that the present invention accomplishes its intended objects.",
"While embodiments of the present invention have been described in detail, that is for the purpose of illustration, not limitation."
] |
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Application Ser. No. 60/402,535, entitled “Mission Specific PET”, filed Aug. 12, 2002, the contents of which are incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and a method for detecting and delineating cancerous lesions, and more particularly an apparatus and a method for effective and affordable early detection of cancerous lesions using gamma rays or other radiation to obtain image data.
2. Description of the Related Art
As medical therapies become more biochemically specific, medical researchers and practitioners have turned to molecular imaging to develop new therapies and guide treatment with these therapies. Positron emission tomography (“PET”) is the archetypal molecular imaging device, due to its high sensitivity to extremely small amounts of biochemically-relevant molecular probes. With such small amounts (e.g., tracer quantities), it is possible to monitor biochemical processes without substantially altering enzymatic kinetic rates.
The detection of early primary cancers with whole-body PET has been less successful than the detection of metastatic activity. This performance difference has been ascribed to instrumental limitations, as well as biological differences between primary cancers as compared to metastases. In general, it is preferable to detect primary cancers when they are small, since the chances of cure and control are substantially increased. The small size of early cancer reduces lesion detectability because of the finite resolution of the PET device, which effectively reduces lesion-to-background contrast. In the PET field, reduced lesion-to-background contrast can be quantitatively measured with the recovery coefficient. This effect has been extensively explored in phantom and clinical trials by Dr. Lee Adler. For example, see “Simultaneous Recovery of Size and Radioactivity Concentration of Small Spheroids with PET Data”, C. Chen, L. Adler et al., J. Nucl. Med. 40(1), 1999, pp. 118–130; and “A Non-Linear Spatially Variant Object-Dependent System Model for Prediction and Correction of Partial Volume Effect in PET”, C. Chen, L. Adler et al., IEEE Trans. Med. Imag. 17:214–227, 1998.
In U.S. patent application Ser. No. 09/737,119, Publication No. 20010040219, Cherry et al. disclose a detector for use in a dedicated PET scanner for cancer applications, particularly breast cancer applications, using at least two detector plates containing arrays of LSO or light-equivalent scintillating crystals and a fiber-optic bundle serving as a light-guide between the scintillator arrays and photomultiplier tubes. However, in the Cherry system, a fiber-optic bundle must be placed in at least two detector plates. In addition, in the Cherry system, the fiber-optic light guides are attached to the scintillator arrays and to the photomultipliers permanently, and these attachments are fixed and not removable. Such a fixed and non-removable arrangement may lead to practical difficulties when, for example, a medical intervention using data provided by the system requires physical access that may be obstructed by the fibers, or when the scintillator arrays and/or fiber optics are contaminated by body fluids so as to require disposal or sterilization. Thus, there is a need for a more flexible PET scanner system that allows the optical fibers to be removable from a photomultiplier or scintillator.
SUMMARY OF THE INVENTION
Advantageously, the invention provides a new algorithm for imaging reconstruction and simulation methods, including an application of Monte Carlo methods or deterministic sampling using Gaussian quadrature to constructing a transition matrix for purposes of iterative image reconstruction. The invention also provides the advantageous feature of an application of deterministic sampling using Gaussian quadrature to perform a transport calculation for purposes of simulating a medical imaging system which is sensitive to gamma-ray or other radiation emitted by the body.
In another aspect, the invention advantageously provides a handheld gamma camera or PET system with a disposable detector head, including a configuration of a gamma camera or PET scanner in which optical fibers or bundles of optical fibers are coupled to a scintillator or array of scintillators and the other end of the optical fibers or bundles of optical fibers are coupled to a light-sensitive camera (for example a photomultiplier). The invention may further include a mechanism to rapidly couple and/or decouple the optical fiber or fibers from the light sensitive camera or from the scintillator or array of scintillators so that the detector can be disposed of or sterilized without damaging the light-sensitive camera. The invention may further include a configuration in which a fiber-optic array couples one detector plate to a light-sensitive camera, while a second detector plate does not require a fiber-optic array.
In another aspect, the invention advantageously provides a free-hand scanner using the aforementioned new algorithm for imaging reconstruction and simulation to generate a transition matrix (which relates response of detector geometric properties to source geometry) which is used to reconstruct images.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a diagram of a PEM-2400 dedicated breast camera mounted in a stereotactic x-ray mammography unit.
FIG. 2 shows a hot spot phantom diagram that illustrates clear visualization of 1.5 mm hot spots.
FIG. 3 shows a graph of an exemplary position of detector heads from a hand-held PET scanner.
FIG. 4 illustrates an exemplary diagram of a graphical user interface that shows hand-held PET scanner detector heads as rigid bodies, with lines of response generated by a source between the detector heads.
FIG. 5 shows an exemplary graph of an energy spectrum of a crystal in a compact array for endoscopy.
FIG. 6 shows a side view of a detector array according to a preferred embodiment of the invention. The detector array comprises scintillating crystals, each of which is attached to a fiber-optic tail. The fiber-optic tails which are arranged in a bundle.
FIG. 7 shows a diagram of the fiber optics as they separate from the bundle and are attached to a position-sensitive photomultiplier face, as constructed according to a preferred embodiment of the invention.
FIG. 8 shows a schematic drawing of a prostate imaging device having biopsy and ultrasound compatibility, according to a preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Reduced lesion detectability due to resolution limitations is a well-known phenomenon in the medical imaging arena. For example, the exacting requirements of breast cancer detection have led to construction of ultrahigh resolution x-ray devices, specifically designed for breast imaging. Naviscan PET Systems (formerly known as PEM Technologies) has set the standard for dedicated breast imaging using PET; for example, see U.S. Pat. No. 5,252,830. The first Naviscan PET Systems product was a breast-specific PET scanner with better than 3-mm full-width half maximum [FWHM] spatial resolution.
Just as in x-ray imaging, there are often good reasons to build mission-specific PET imaging devices. Building a whole-body PET scanner with 2-mm resolution, as would be required to reliably detect early cancers in the breast, would be very expensive. Whole-body PET scanners utilize hundreds of expensive photomultipliers which result in resolutions on the order of 6-mm FWHM. Improving spatial resolution by a factor of three, as would be needed to significantly reduce contrast recovery problems, would require replacing conventional photomultipliers by even more expensive models, substantially increasing construction costs. Although ingenious schemes have been developed that attempt to reduce construction costs of high resolution PET systems, these methods have yet to be applied to commercially available whole-body products, and would in any case be just as effective in reducing the cost of smaller dedicated mission-specific instruments. In a dedicated breast PET device, since the field of view is restricted to the breast, reaching even sub-millimeter resolution, as has been achieved by using of state-of-the-art technology, could potentially become affordable.
Aside from purely economic considerations, there are functions that are considered necessary for certain clinical missions that are difficult if not impossible to deliver with conventional whole-body PET scanners. These functions relate to cross-modality correlations (e.g., with ultrasound or x-ray mammography) and interventional/biopsy capability. Newly-introduced imaging devices that combine PET with x-ray computed tomography (i.e., PET/CT scanners) can be used to perform biopsy of lesions in stable organs (e.g., liver metastases), but would be difficult to use for mobile organs that are less amenable to CT-guided biopsy (e.g., ovary or bowel). With respect to interventional/biopsy capability, short scan times are highly desirable, and dedicated PET instruments can benefit from significantly increased collection efficiencies as compared to conventional ring scanners. In the case of dedicated breast PET, the combination of reduced attenuation losses (e.g., 5 cm of fatty breast tissue as compared to 50 cm of chest and breast) and increased solid angle coverage—due to reduced r-squared distance between the body part and the detector—can dramatically decrease scan time required to confidently visualize subtle lesions. It is noted that a lesion is defined as a local area in the body which may be harmful to the patient. For example, a lesion may be a cancer, an inflammatory process, or a necrotic area of tissue.
Not all clinical problems merit the development of mission-specific scanners. However, Naviscan PET Systems has identified several medical market niches in oncology that may justify the development and commercialization of such products: breast, prostate, ovary, and liver metastases. Outside of oncology, there are potential applications to cardiac surgery and treatment of infectious disease; for example, selection of appropriate borders for amputation in osteomyelitis, and selection of locations for endoscopic biopsy in tuberculosis. From a commercialization point of view, there are several examples of mission-specific products that have been highly valued in the marketplace once reimbursement patterns became well-defined. Examples include bone densitometry and spot digital mammography for breast biopsy.
From a public health point of view, the construction of cost-effective devices incorporating PET technology enables diffusion of molecular imaging into the broader medical community. This pattern is expected to improve delivery of health care to the public by allowing non-radiological specialists to deliver therapy on a more rational basis (e.g., on the basis of individual biochemistry profiles), consistent with current concepts in oncology which look at the individual's tumor type as only the first step in choosing tailored therapy.
Outside of oncology, PET has been shown to be effective in predicting myocardial viability. If a portable PET scanner is available for use in the cardiac surgery suite, it may be possible to immediately assess the adequacy of supply to reperfused myocardium. Portable PET scans can be used to guide bone removal in osteomyelitis, potentially reducing the degree of amputation required to effect a cure.
Monte Carlo methods may be used advantageously in conjunction with the present invention. Historically, simulation studies were first developed when experiments were prohibitive in cost, time, or other factors. Von Neumann coined the phrase Monte Carlo when he applied random sampling to calculate neutron diffusion rates during the Manhattan Project. Monte Carlo simulations are based on the construction of a stochastic model in which the expectation value of a random variable is equivalent to the measured physical quantity. This expectation value is estimated by the average of multiple independent samples representing this random variable, obtained by random sampling. For example, consider a random variable X which is needed for a problem involving photon propagation in tissue. This variable might be the angle of deflection a scattered photon may experience due to a scattering event. Associated with this random variable is a probability density function over a given interval. The integral of this probability density function is normalized to unity over this interval, which corresponds to the fact that any sampling of the random variable must lie in the given interval. To model a more complex system, the outcomes of each random sampling are accumulated under appropriate weights and any rejection algorithms to arrive at an expected value of a given measurable physical quantity.
Monte Carlo techniques were introduced into medical physics by Raeside in 1976 and to PET by Keller in 1983. Full PET devices have been simulated using GEANT, a code developed by high energy physicists that included the ability to specify detector geometry, and with adaptations of older codes developed by Keller and Lupton. These simulations have modeled classic ring geometries for PET devices for both human and animal varieties. Works-in-progress presentations have been made about parallel-plate and square detector rings.
Preliminary results have been obtained by the present inventors demonstrating proof-of-principle for an endoscopic PET scanner and for a novel application of code to replace traditional Monte Carlo calculations. Naviscan PET Systems has used Monte Carlo methods extensively in conducting simulations of both fixed and free-hand geometries. For example, Monte Carlo methods have been used to create transition matrices for reconstruction. Specifically, these methods relate to the reconstruction that is required to provide a high quality image of an unknown distribution of radioactive sources. Reconstruction is often performed with an iterative technique, in which a computer compares the calculated response of the imaging system to successive guesses as to the distribution with the actual measured response as measured by the imaging system. In order to calculate the response of the imaging system to these guesses, a “transition matrix” is used to model the imaging system. In most imaging devices, this transition matrix is generated by examining a fixed detector geometry and a fixed volume in which the unknown radioactive source distribution is allowed to occupy. In accordance with an embodiment of the invention, for more flexible imaging systems, the position of a freed detector head is determined, and the transition matrix is calculated using Monte Carlo or deterministic sampling methods. In accordance with another embodiment of the invention, Monte Carlo and/or deterministic sampling methods may be used for modeling systems with the aim of improving design.
It is known that a transition matrix that models the response of the detection system to arbitrary distributions of radioactivity is needed in order to assist a PET system in performing image formation (e.g., through iterative image reconstruction). Other types of reconstructions, such as filtered backprojections, may also employ transition matrices to form an image. According to a preferred embodiment of the present invention, the use of Monte Carlo and/or deterministic sampling methods allow the PET system to have great flexibility, because the trajectory of the fiber-optic mounted scintillator can be tracked by a position sensor. This trajectory can be inputted into the Monte Carlo and/or deterministic sampling algorithm to create a transition matrix for a PET or gamma ray imaging system incorporating the tracked fiber-optic mounted scintillator array. The imaging system may include other components, possibly using timing coincidence (also referred to as coincidence gating, or coincident gating). Specifically, the other components may include a detector plate mounted outside the body. Additionally, tracking of the fiber-optic mounted scintillator array may be accomplished with a method other than a position sensor, for example, by using a position encoder such as a moveable lever that can place the scintillator array in a known set of positions.
Coincidence gating is the method of aggregating events depending on the period of time between detection of these events by the imaging system. Referring to FIG. 8 , coincidence gating 820 can be applied in electronic form (e.g., with AND circuitry that only allows pulses within a specific time interval to generate a gate signal), or post-acquisition by examination of list files showing when each event was detected by the imaging system. Other forms of coincidence gating or detection may be used as well.
As is traditional for light guide fabricators, dedicated breast imaging PET designs were performed with the assistance of Monte Carlo models, which enabled clear identification of 2-mm crystal pitches with very low profile light guides. These low-profile light guides enabled the building of PET detector heads for mammography that were very compact (e.g., less than 6 cm deep). Referring to FIG. 1 , a diagram of a PEM-2400 breast camera mounted in a Lorad stereotactic x-ray mammography unit is shown. These detector heads are so small that they can stay mounted in a stereotactic mammography camera without requiring removal of the x-ray detector. Referring to FIG. 2 , an exemplary hot spot phantom diagram that illustrates clear visualization of 1.5 mm hot spots can be obtained from a camera such as that illustrated in FIG. 1 .
Referring to FIGS. 3 and 4 , for free-hand geometries, it is possible to collect the information about the orbits experienced by a hand-held scanner and project all possible line-pairs from a source volume that could be intercepted by the scanner traversing the orbit. In FIG. 3 , an exemplary position of detector heads from a hand-held PET scanner is shown. FIG. 4 illustrates an exemplary diagram of a graphical user interface that shows hand-held PET scanner detector heads as rigid bodies, with lines of response generated by a source between the detector heads, including lines of response for zero attitude 405 , azimuth rotation 410 , elevation rotation 415 , and roll rotation 420 . The present inventors have extended this principle to allow the orbit itself to be specified through a random walk, in order to compare various detector geometries. Prototype free-hand SPECT and PET devices have been built, which are able to image point sources and remove overlapping activity by using Monte Carlo based reconstructions.
For a stochastic orbit, the field-of-view of the system is constrained mathematically within a specified detection volume in which the detectors can be located.
Naviscan PET Systems has pioneered adoption of a new computational method that promises to significantly reduce computational time for simulations. This method incorporates deterministic sampling using Gaussian quadrature, and has been shown to speed up transport codes in plasma physics by a factor of one thousand. The code is fast, efficient, rapidly convergent, and highly parallelizable. It is based on a technique of replacing each call to a random number generator with a carefully chosen and deterministic realization of the random variable. In other words, in place of calling a random number generator, the weights and abscissas of the relevant Gaussian quadrature parameters are used. For example, in many imaging algorithms, a Monte Carlo calculation requires a random realization of the random variable N(0,1) (i.e., a random variable of mean zero and variance unity) defined by a Gaussian probability density function p(x)=exp(−x 2 /2). In the case of p(x), the relevant Gaussian quadrature parameters are simply the well-known Gauss-Hermite weights w j and abscissas q j . For example, instead of making two Monte Carlo random samplings, two deterministic samplings are obtained from the n=2 Gauss-Hermite abscissa-weight pairs. For n=2, these pairs are simply q j =(−0.57735, +0.57735) and w j =(1, 1).
This method is based on exploiting a theorem from Gaussian integration that states that for a function ƒ(x), the following approximation:
∫ - ∞ ∞ f ( x ) exp ( - x 2 / 2 ) ⅆ x ≈ 2 π ∑ j = 1 J w j f ( q j )
becomes exact if the weights w j and abscissas q j are Gauss-Hermite and the function ƒ(x) is a linear combination of the 2J−1 polynomials x 0 , x 1 , . . . , x 2J−1 .
In addition to compact light guides for breast imaging, the present inventors have developed compact cameras for endoscopy that fit on fiber optic bundles according to a preferred embodiment of the invention. Referring to FIG. 5 , an exemplary energy spectrum for one of 24 crystals in an array is shown. In example shown in FIG. 5 , the crystal that produced the energy spectrum is approximately 2 mm thick, and the compact array has a diameter of approximately 1 cm. Referring to FIG. 6 , an exemplary array design for a detector head of the endoscopy camera is shown. In this example, the detector head includes a total of 32 lutetium oxyorthosilicate (“LSO”) crystals 605 , arranged in an 8×4 array. Each LSO crystal 605 is 2 mm×4 mm×5 mm. Thus, in this example, the total volume required by the detector head is approximately 1.3 cm 3 . A conventional small field-of-view array volume is about 43 cm 3 , which is about 33 times as large as that depicted in FIG. 6 . Thus, the detector shown in FIG. 6 represents an improved pixel resolution of a factor of 33. For example, if a conventional detector yields a count rate of 1 kHz, then the detector of FIG. 6 will yield a count rate of about 30 Hz, which is equivalent to about 1 true Hz per pixel. In addition, each LSO crystal 605 couples with seven optical fibers, and, referring also to FIG. 8 , the coupling 815 between the crystal 605 , or array of crystals 605 contained within component 805 , and the fibers is designed so that the fibers can be easily decoupled from the crystal. In other words, although the fibers are actually physically attached to the crystal, the fibers are removable and disposable, for situations in which, for example, a medical intervention requires access that would otherwise be obstructed by the fibers. The quality of removability of the fibers may be implemented by fiber-optic couplers and ferrules, or by other conventional methods of coupling fiber-optic bundles to imaging devices or to other fiber-optic bundles. Referring to FIG. 7 , a cross-sectional view of a six-by-six array is also shown, including several fiber optic bundles 705 on the face 710 of the camera. Each of the fiber optic bundles 705 includes seven fibers, each of which is approximately 1 mm in diameter.
Referring to FIG. 8 , the present invention further provides a design for a prototype endoscopic PET camera. This camera has two components, including an ultra-compact endoscopic component 805 in coincidence with a larger external component 810 , similar to a device for prostate imaging as disclosed in U.S. patent application Ser. No. 10/196,560. The device includes two components: (1) an ultra-compact intracavitary component 805 comprising a small (e.g., 1 cm diameter) array of thin (e.g., 2 mm by 5 mm) LSO crystals mounted on fiber optics that are attached to a position-sensitive photomultiplier, and (2) an external component array 810 of detectors and photomultipliers placed anterior or posterior to the patient. In principle, placing detectors on the ends of fibers has been done before (e.g., for animal scanners), although the motivation in those cases was to allow deployment of large photomultipliers in observing a small volume. Gamma detectors have also been placed on the ends of fiber optics in order to build non-imaging gamma probes. The present inventors have extended these concepts to better suit the needs of endoscopists, by making several enabling modifications, including the following: 1) introducing a quick-release optical fiber coupling so that the detector head is separable from the photomultiplier, and is therefore disposable; 2) adding position sensing to the detector head so that events can be correctly placed in sinograms; 3) including flexible Monte Carlo-based reconstruction algorithms to allow reconstruction of events from the mobile detector head and a second detector head placed external to the body; and 4) using deterministic sampling to accelerate these reconstruction algorithms. These advantageous features allow the present invention to be useful to surgeons and endoscopists, who can kill or remove cancer or inflammatory cells and then use the present invention to check to ensure that the cells are actually removed or dying. Then, the present invention can be further utilized to check the field of surgery (or other therapy) to determine whether residual viable cells are present, proceeding iteratively to minimize the number of residual viable cells.
While the present invention has been described with respect to what is presently considered to be the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. For example, the above descriptions of embodiments of the invention are primarily couched in terms of using a PET scanner system. Those skilled in the art will understand that a compact gamma camera system using coincidence gating (i.e., a coincident gamma camera system) may also be used. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
The contents of each of the following publications are hereby incorporated by reference:
1) S. Holbrook, “Newsline Commentary”, Journal of Nuclear Medicine 43(2), p. 12N, 2002. 2) L. P. Adler et al., “Evaluation of Breast Masses and Axillary Lymph Nodes with [F-18] 2-Deoxy-2-fluoro-D-glucose PET”, Radiology, 1993, 187: 743–750. 3) B. Fisher et al., “Cancer of the Breast: Size of Neoplasm and Diagnosis”, Cancer, 1969, 24:1071–1080. 4) R. M. Kessler et al., “Analysis of emission tomographic scan data: limitations imposed by resolution and background”, J. Comput. Assist Tomography, 1984, 8:514–522. 5) C. Chen, L. Adler et al., “Simultaneous Recovery of Size and Radioactivity Concentration of Small Spheroids with PET Data”, J. Nucl. Med., 40(1), pp. 118–130, 1999. 6) C. Chen. L. Adler et al., “A non-linear spatially-variant object-dependent system model for prediction and correction of partial volume effect in PET”, IEEE Trans. Med. Imag., 17: 214–227, 1998. 7) U.S. Pat. No. 5,252,830. 8) I. Weinberg et al., “Preliminary Results for Positron Emission Mammography: Real-Time Functional Breast Imaging in a Conventional Mammography Gantry”, Eur. J. Nucl. Med., 23(7):804–806, 1996. 9) R. Miyaoka, “Dynamic high resolution positron emission imaging of rats”, Biomed. Sci. Instrum. 1991, 27:35–42. 10) D. Townsend et al., “High Density Avalanche Chamber (HIDAC) Positron Camera”, J. Nucl. Med., 28:1554–1562, 1987. 11) C. Thompson et al., “Feasibility Study for Positron Emission Mammography”, Med. Phys. 1994, 21:529–538. 12) R. Ott, “The Applications of Positron Emission Tomography to Oncology”, Br. J. Cancer, 1991, 63:343–345. 13) J. Tillisch et al., “Reversibility of cardiac wall motion abnormalities predicted by positron emission tomography”, New Engl. J. Med. 314: 884–8, 1986. 14) D. McCracken, “The Monte Carlo method”, Sci. Am. 192, 90–96 (1955). 15) D. Raeside, “Monte Carlo principles and applications”, Phys. Med. Biol. 21, 181–197 (1976). 16) N. Keller and J. Lupton, “PET detector ring aperture function calculations using Monte Carlo techniques”, IEEE Trans. Nucl. Sci. 30, pp. 676–680 (1983). 17) C. Thompson et al., “PETSIM: Monte Carlo simulation of all sensitivity and resolution parameters of cylindrical positron imaging systems”, Phys. Med. Biol., 1992, Vol. 37(3), pp. 731–749. 18) W. Moses et al., “Design of a High Resolution, High Sensitivity PET Camera for Human Brains and Small Animals”, IEEE Transactions on Nuclear Science NS-44, pp. 1487–1491, 1977. 19) W. Worstell et al., “Monte Carlo-based Implementation of the ML-EM Algorithm for 3-D PT Reconstruction”, Proceedings IEEE Nucl. Sci. Symp. 1997. 20) I. Weinberg et al., “Crystal Identification in Modular 2-Dimensional Array Detectors for High Spatial Resolution PET”, Proc. Intl. Wksp. on Physics and Engineering in Computerized Multi-dimensional Imaging and Processing, SPIE V. 21) I. Weinberg et al., “Biopsy-Ready PEM Scanner with Real-Time X-Ray Correlation Capability”, accepted for presentation at IEEE Nucl. Sci. Symp. 2002. 22) I. Weinberg et al., “Implementing reconstruction with hand-held gamma cameras”, Proceedings IEEE Nuc. Sci. Symp. 2000. 23) D. S. Lemons and B. J. Albright, “Quiet Monte-Carlo radiation transport”, Journal of Quantitative Spectroscopy and Radiation Transfer, Vol. 74, pp. 719–729 (2002). 24) U.S. patent application Ser. No. 10/196,560, filed Jul. 17, 2002. 25) A. Chatziioannou et al., “Performance Evaluation of Micro-PET: A High-Resolution Lutetium Orthosolicate PET Scanner for Animal Imaging”, J. Nucl. Med. 1999, 40:1164–1175. 26) F. Daghighian, et al., “Intraoperative beta probe: a device for detecting tissue labeled with positron or electron emitting isotopes during surgery”, Med. Phys., Vol. 21(1), pp. 153–157, January 1994. 27) U.S. application Ser. No. 09/737,119, Publication No. 20010040219, filed Dec. 14, 2000. 28) U.S. application Ser. No. 09/833,110, filed Apr. 11, 2001. 29) U.S. Pat. No. 6,331,703. 30) U.S. patent application Ser. No. 10/027,759, filed Dec. 21, 2001. | A handheld gamma camera or PET system with a disposable detector head is provided. This system includes a configuration of a gamma camera or PET scanner in which optical fibers or bundles of optical fibers are coupled to a scintillator or array of scintillators and the other end of the optical fibers or bundles of optical fibers are coupled to a light-sensitive camera, such as a photomultiplier. The system may further include a mechanism to rapidly couple and/or decouple the optical fiber or fibers from the light sensitive camera or from the scintillator or array of scintillators so that the detector can be disposed of or sterilized without damaging the light-sensitive camera. A method for image reconstruction and image simulation is also provided. The method includes an application of deterministic sampling using Gaussian quadrature parameters to construct a transition matrix for purposes of image reconstruction. | Identify and summarize the most critical features from the given passage. | [
"CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Application Ser.",
"No. 60/402,535, entitled “Mission Specific PET”, filed Aug. 12, 2002, the contents of which are incorporated by reference herein.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present invention relates to an apparatus and a method for detecting and delineating cancerous lesions, and more particularly an apparatus and a method for effective and affordable early detection of cancerous lesions using gamma rays or other radiation to obtain image data.",
"Description of the Related Art As medical therapies become more biochemically specific, medical researchers and practitioners have turned to molecular imaging to develop new therapies and guide treatment with these therapies.",
"Positron emission tomography (“PET”) is the archetypal molecular imaging device, due to its high sensitivity to extremely small amounts of biochemically-relevant molecular probes.",
"With such small amounts (e.g., tracer quantities), it is possible to monitor biochemical processes without substantially altering enzymatic kinetic rates.",
"The detection of early primary cancers with whole-body PET has been less successful than the detection of metastatic activity.",
"This performance difference has been ascribed to instrumental limitations, as well as biological differences between primary cancers as compared to metastases.",
"In general, it is preferable to detect primary cancers when they are small, since the chances of cure and control are substantially increased.",
"The small size of early cancer reduces lesion detectability because of the finite resolution of the PET device, which effectively reduces lesion-to-background contrast.",
"In the PET field, reduced lesion-to-background contrast can be quantitatively measured with the recovery coefficient.",
"This effect has been extensively explored in phantom and clinical trials by Dr. Lee Adler.",
"For example, see “Simultaneous Recovery of Size and Radioactivity Concentration of Small Spheroids with PET Data”, C. Chen, L. Adler et al.",
", J. Nucl.",
"Med.",
"40(1), 1999, pp. 118–130;",
"and “A Non-Linear Spatially Variant Object-Dependent System Model for Prediction and Correction of Partial Volume Effect in PET”, C. Chen, L. Adler et al.",
", IEEE Trans.",
"Med.",
"Imag.",
"17:214–227, 1998.",
"In U.S. patent application Ser.",
"No. 09/737,119, Publication No. 20010040219, Cherry et al.",
"disclose a detector for use in a dedicated PET scanner for cancer applications, particularly breast cancer applications, using at least two detector plates containing arrays of LSO or light-equivalent scintillating crystals and a fiber-optic bundle serving as a light-guide between the scintillator arrays and photomultiplier tubes.",
"However, in the Cherry system, a fiber-optic bundle must be placed in at least two detector plates.",
"In addition, in the Cherry system, the fiber-optic light guides are attached to the scintillator arrays and to the photomultipliers permanently, and these attachments are fixed and not removable.",
"Such a fixed and non-removable arrangement may lead to practical difficulties when, for example, a medical intervention using data provided by the system requires physical access that may be obstructed by the fibers, or when the scintillator arrays and/or fiber optics are contaminated by body fluids so as to require disposal or sterilization.",
"Thus, there is a need for a more flexible PET scanner system that allows the optical fibers to be removable from a photomultiplier or scintillator.",
"SUMMARY OF THE INVENTION Advantageously, the invention provides a new algorithm for imaging reconstruction and simulation methods, including an application of Monte Carlo methods or deterministic sampling using Gaussian quadrature to constructing a transition matrix for purposes of iterative image reconstruction.",
"The invention also provides the advantageous feature of an application of deterministic sampling using Gaussian quadrature to perform a transport calculation for purposes of simulating a medical imaging system which is sensitive to gamma-ray or other radiation emitted by the body.",
"In another aspect, the invention advantageously provides a handheld gamma camera or PET system with a disposable detector head, including a configuration of a gamma camera or PET scanner in which optical fibers or bundles of optical fibers are coupled to a scintillator or array of scintillators and the other end of the optical fibers or bundles of optical fibers are coupled to a light-sensitive camera (for example a photomultiplier).",
"The invention may further include a mechanism to rapidly couple and/or decouple the optical fiber or fibers from the light sensitive camera or from the scintillator or array of scintillators so that the detector can be disposed of or sterilized without damaging the light-sensitive camera.",
"The invention may further include a configuration in which a fiber-optic array couples one detector plate to a light-sensitive camera, while a second detector plate does not require a fiber-optic array.",
"In another aspect, the invention advantageously provides a free-hand scanner using the aforementioned new algorithm for imaging reconstruction and simulation to generate a transition matrix (which relates response of detector geometric properties to source geometry) which is used to reconstruct images.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a diagram of a PEM-2400 dedicated breast camera mounted in a stereotactic x-ray mammography unit.",
"FIG. 2 shows a hot spot phantom diagram that illustrates clear visualization of 1.5 mm hot spots.",
"FIG. 3 shows a graph of an exemplary position of detector heads from a hand-held PET scanner.",
"FIG. 4 illustrates an exemplary diagram of a graphical user interface that shows hand-held PET scanner detector heads as rigid bodies, with lines of response generated by a source between the detector heads.",
"FIG. 5 shows an exemplary graph of an energy spectrum of a crystal in a compact array for endoscopy.",
"FIG. 6 shows a side view of a detector array according to a preferred embodiment of the invention.",
"The detector array comprises scintillating crystals, each of which is attached to a fiber-optic tail.",
"The fiber-optic tails which are arranged in a bundle.",
"FIG. 7 shows a diagram of the fiber optics as they separate from the bundle and are attached to a position-sensitive photomultiplier face, as constructed according to a preferred embodiment of the invention.",
"FIG. 8 shows a schematic drawing of a prostate imaging device having biopsy and ultrasound compatibility, according to a preferred embodiment of the invention.",
"DETAILED DESCRIPTION OF THE INVENTION Reduced lesion detectability due to resolution limitations is a well-known phenomenon in the medical imaging arena.",
"For example, the exacting requirements of breast cancer detection have led to construction of ultrahigh resolution x-ray devices, specifically designed for breast imaging.",
"Naviscan PET Systems (formerly known as PEM Technologies) has set the standard for dedicated breast imaging using PET;",
"for example, see U.S. Pat. No. 5,252,830.",
"The first Naviscan PET Systems product was a breast-specific PET scanner with better than 3-mm full-width half maximum [FWHM] spatial resolution.",
"Just as in x-ray imaging, there are often good reasons to build mission-specific PET imaging devices.",
"Building a whole-body PET scanner with 2-mm resolution, as would be required to reliably detect early cancers in the breast, would be very expensive.",
"Whole-body PET scanners utilize hundreds of expensive photomultipliers which result in resolutions on the order of 6-mm FWHM.",
"Improving spatial resolution by a factor of three, as would be needed to significantly reduce contrast recovery problems, would require replacing conventional photomultipliers by even more expensive models, substantially increasing construction costs.",
"Although ingenious schemes have been developed that attempt to reduce construction costs of high resolution PET systems, these methods have yet to be applied to commercially available whole-body products, and would in any case be just as effective in reducing the cost of smaller dedicated mission-specific instruments.",
"In a dedicated breast PET device, since the field of view is restricted to the breast, reaching even sub-millimeter resolution, as has been achieved by using of state-of-the-art technology, could potentially become affordable.",
"Aside from purely economic considerations, there are functions that are considered necessary for certain clinical missions that are difficult if not impossible to deliver with conventional whole-body PET scanners.",
"These functions relate to cross-modality correlations (e.g., with ultrasound or x-ray mammography) and interventional/biopsy capability.",
"Newly-introduced imaging devices that combine PET with x-ray computed tomography (i.e., PET/CT scanners) can be used to perform biopsy of lesions in stable organs (e.g., liver metastases), but would be difficult to use for mobile organs that are less amenable to CT-guided biopsy (e.g., ovary or bowel).",
"With respect to interventional/biopsy capability, short scan times are highly desirable, and dedicated PET instruments can benefit from significantly increased collection efficiencies as compared to conventional ring scanners.",
"In the case of dedicated breast PET, the combination of reduced attenuation losses (e.g., 5 cm of fatty breast tissue as compared to 50 cm of chest and breast) and increased solid angle coverage—due to reduced r-squared distance between the body part and the detector—can dramatically decrease scan time required to confidently visualize subtle lesions.",
"It is noted that a lesion is defined as a local area in the body which may be harmful to the patient.",
"For example, a lesion may be a cancer, an inflammatory process, or a necrotic area of tissue.",
"Not all clinical problems merit the development of mission-specific scanners.",
"However, Naviscan PET Systems has identified several medical market niches in oncology that may justify the development and commercialization of such products: breast, prostate, ovary, and liver metastases.",
"Outside of oncology, there are potential applications to cardiac surgery and treatment of infectious disease;",
"for example, selection of appropriate borders for amputation in osteomyelitis, and selection of locations for endoscopic biopsy in tuberculosis.",
"From a commercialization point of view, there are several examples of mission-specific products that have been highly valued in the marketplace once reimbursement patterns became well-defined.",
"Examples include bone densitometry and spot digital mammography for breast biopsy.",
"From a public health point of view, the construction of cost-effective devices incorporating PET technology enables diffusion of molecular imaging into the broader medical community.",
"This pattern is expected to improve delivery of health care to the public by allowing non-radiological specialists to deliver therapy on a more rational basis (e.g., on the basis of individual biochemistry profiles), consistent with current concepts in oncology which look at the individual's tumor type as only the first step in choosing tailored therapy.",
"Outside of oncology, PET has been shown to be effective in predicting myocardial viability.",
"If a portable PET scanner is available for use in the cardiac surgery suite, it may be possible to immediately assess the adequacy of supply to reperfused myocardium.",
"Portable PET scans can be used to guide bone removal in osteomyelitis, potentially reducing the degree of amputation required to effect a cure.",
"Monte Carlo methods may be used advantageously in conjunction with the present invention.",
"Historically, simulation studies were first developed when experiments were prohibitive in cost, time, or other factors.",
"Von Neumann coined the phrase Monte Carlo when he applied random sampling to calculate neutron diffusion rates during the Manhattan Project.",
"Monte Carlo simulations are based on the construction of a stochastic model in which the expectation value of a random variable is equivalent to the measured physical quantity.",
"This expectation value is estimated by the average of multiple independent samples representing this random variable, obtained by random sampling.",
"For example, consider a random variable X which is needed for a problem involving photon propagation in tissue.",
"This variable might be the angle of deflection a scattered photon may experience due to a scattering event.",
"Associated with this random variable is a probability density function over a given interval.",
"The integral of this probability density function is normalized to unity over this interval, which corresponds to the fact that any sampling of the random variable must lie in the given interval.",
"To model a more complex system, the outcomes of each random sampling are accumulated under appropriate weights and any rejection algorithms to arrive at an expected value of a given measurable physical quantity.",
"Monte Carlo techniques were introduced into medical physics by Raeside in 1976 and to PET by Keller in 1983.",
"Full PET devices have been simulated using GEANT, a code developed by high energy physicists that included the ability to specify detector geometry, and with adaptations of older codes developed by Keller and Lupton.",
"These simulations have modeled classic ring geometries for PET devices for both human and animal varieties.",
"Works-in-progress presentations have been made about parallel-plate and square detector rings.",
"Preliminary results have been obtained by the present inventors demonstrating proof-of-principle for an endoscopic PET scanner and for a novel application of code to replace traditional Monte Carlo calculations.",
"Naviscan PET Systems has used Monte Carlo methods extensively in conducting simulations of both fixed and free-hand geometries.",
"For example, Monte Carlo methods have been used to create transition matrices for reconstruction.",
"Specifically, these methods relate to the reconstruction that is required to provide a high quality image of an unknown distribution of radioactive sources.",
"Reconstruction is often performed with an iterative technique, in which a computer compares the calculated response of the imaging system to successive guesses as to the distribution with the actual measured response as measured by the imaging system.",
"In order to calculate the response of the imaging system to these guesses, a “transition matrix”",
"is used to model the imaging system.",
"In most imaging devices, this transition matrix is generated by examining a fixed detector geometry and a fixed volume in which the unknown radioactive source distribution is allowed to occupy.",
"In accordance with an embodiment of the invention, for more flexible imaging systems, the position of a freed detector head is determined, and the transition matrix is calculated using Monte Carlo or deterministic sampling methods.",
"In accordance with another embodiment of the invention, Monte Carlo and/or deterministic sampling methods may be used for modeling systems with the aim of improving design.",
"It is known that a transition matrix that models the response of the detection system to arbitrary distributions of radioactivity is needed in order to assist a PET system in performing image formation (e.g., through iterative image reconstruction).",
"Other types of reconstructions, such as filtered backprojections, may also employ transition matrices to form an image.",
"According to a preferred embodiment of the present invention, the use of Monte Carlo and/or deterministic sampling methods allow the PET system to have great flexibility, because the trajectory of the fiber-optic mounted scintillator can be tracked by a position sensor.",
"This trajectory can be inputted into the Monte Carlo and/or deterministic sampling algorithm to create a transition matrix for a PET or gamma ray imaging system incorporating the tracked fiber-optic mounted scintillator array.",
"The imaging system may include other components, possibly using timing coincidence (also referred to as coincidence gating, or coincident gating).",
"Specifically, the other components may include a detector plate mounted outside the body.",
"Additionally, tracking of the fiber-optic mounted scintillator array may be accomplished with a method other than a position sensor, for example, by using a position encoder such as a moveable lever that can place the scintillator array in a known set of positions.",
"Coincidence gating is the method of aggregating events depending on the period of time between detection of these events by the imaging system.",
"Referring to FIG. 8 , coincidence gating 820 can be applied in electronic form (e.g., with AND circuitry that only allows pulses within a specific time interval to generate a gate signal), or post-acquisition by examination of list files showing when each event was detected by the imaging system.",
"Other forms of coincidence gating or detection may be used as well.",
"As is traditional for light guide fabricators, dedicated breast imaging PET designs were performed with the assistance of Monte Carlo models, which enabled clear identification of 2-mm crystal pitches with very low profile light guides.",
"These low-profile light guides enabled the building of PET detector heads for mammography that were very compact (e.g., less than 6 cm deep).",
"Referring to FIG. 1 , a diagram of a PEM-2400 breast camera mounted in a Lorad stereotactic x-ray mammography unit is shown.",
"These detector heads are so small that they can stay mounted in a stereotactic mammography camera without requiring removal of the x-ray detector.",
"Referring to FIG. 2 , an exemplary hot spot phantom diagram that illustrates clear visualization of 1.5 mm hot spots can be obtained from a camera such as that illustrated in FIG. 1 .",
"Referring to FIGS. 3 and 4 , for free-hand geometries, it is possible to collect the information about the orbits experienced by a hand-held scanner and project all possible line-pairs from a source volume that could be intercepted by the scanner traversing the orbit.",
"In FIG. 3 , an exemplary position of detector heads from a hand-held PET scanner is shown.",
"FIG. 4 illustrates an exemplary diagram of a graphical user interface that shows hand-held PET scanner detector heads as rigid bodies, with lines of response generated by a source between the detector heads, including lines of response for zero attitude 405 , azimuth rotation 410 , elevation rotation 415 , and roll rotation 420 .",
"The present inventors have extended this principle to allow the orbit itself to be specified through a random walk, in order to compare various detector geometries.",
"Prototype free-hand SPECT and PET devices have been built, which are able to image point sources and remove overlapping activity by using Monte Carlo based reconstructions.",
"For a stochastic orbit, the field-of-view of the system is constrained mathematically within a specified detection volume in which the detectors can be located.",
"Naviscan PET Systems has pioneered adoption of a new computational method that promises to significantly reduce computational time for simulations.",
"This method incorporates deterministic sampling using Gaussian quadrature, and has been shown to speed up transport codes in plasma physics by a factor of one thousand.",
"The code is fast, efficient, rapidly convergent, and highly parallelizable.",
"It is based on a technique of replacing each call to a random number generator with a carefully chosen and deterministic realization of the random variable.",
"In other words, in place of calling a random number generator, the weights and abscissas of the relevant Gaussian quadrature parameters are used.",
"For example, in many imaging algorithms, a Monte Carlo calculation requires a random realization of the random variable N(0,1) (i.e., a random variable of mean zero and variance unity) defined by a Gaussian probability density function p(x)=exp(−x 2 /2).",
"In the case of p(x), the relevant Gaussian quadrature parameters are simply the well-known Gauss-Hermite weights w j and abscissas q j .",
"For example, instead of making two Monte Carlo random samplings, two deterministic samplings are obtained from the n=2 Gauss-Hermite abscissa-weight pairs.",
"For n=2, these pairs are simply q j =(−0.57735, +0.57735) and w j =(1, 1).",
"This method is based on exploiting a theorem from Gaussian integration that states that for a function ƒ(x), the following approximation: ∫ - ∞ ∞ f ( x ) exp ( - x 2 / 2 ) ⅆ x ≈ 2 π ∑ j = 1 J w j f ( q j ) becomes exact if the weights w j and abscissas q j are Gauss-Hermite and the function ƒ(x) is a linear combination of the 2J−1 polynomials x 0 , x 1 , .",
", x 2J−1 .",
"In addition to compact light guides for breast imaging, the present inventors have developed compact cameras for endoscopy that fit on fiber optic bundles according to a preferred embodiment of the invention.",
"Referring to FIG. 5 , an exemplary energy spectrum for one of 24 crystals in an array is shown.",
"In example shown in FIG. 5 , the crystal that produced the energy spectrum is approximately 2 mm thick, and the compact array has a diameter of approximately 1 cm.",
"Referring to FIG. 6 , an exemplary array design for a detector head of the endoscopy camera is shown.",
"In this example, the detector head includes a total of 32 lutetium oxyorthosilicate (“LSO”) crystals 605 , arranged in an 8×4 array.",
"Each LSO crystal 605 is 2 mm×4 mm×5 mm.",
"Thus, in this example, the total volume required by the detector head is approximately 1.3 cm 3 .",
"A conventional small field-of-view array volume is about 43 cm 3 , which is about 33 times as large as that depicted in FIG. 6 .",
"Thus, the detector shown in FIG. 6 represents an improved pixel resolution of a factor of 33.",
"For example, if a conventional detector yields a count rate of 1 kHz, then the detector of FIG. 6 will yield a count rate of about 30 Hz, which is equivalent to about 1 true Hz per pixel.",
"In addition, each LSO crystal 605 couples with seven optical fibers, and, referring also to FIG. 8 , the coupling 815 between the crystal 605 , or array of crystals 605 contained within component 805 , and the fibers is designed so that the fibers can be easily decoupled from the crystal.",
"In other words, although the fibers are actually physically attached to the crystal, the fibers are removable and disposable, for situations in which, for example, a medical intervention requires access that would otherwise be obstructed by the fibers.",
"The quality of removability of the fibers may be implemented by fiber-optic couplers and ferrules, or by other conventional methods of coupling fiber-optic bundles to imaging devices or to other fiber-optic bundles.",
"Referring to FIG. 7 , a cross-sectional view of a six-by-six array is also shown, including several fiber optic bundles 705 on the face 710 of the camera.",
"Each of the fiber optic bundles 705 includes seven fibers, each of which is approximately 1 mm in diameter.",
"Referring to FIG. 8 , the present invention further provides a design for a prototype endoscopic PET camera.",
"This camera has two components, including an ultra-compact endoscopic component 805 in coincidence with a larger external component 810 , similar to a device for prostate imaging as disclosed in U.S. patent application Ser.",
"No. 10/196,560.",
"The device includes two components: (1) an ultra-compact intracavitary component 805 comprising a small (e.g., 1 cm diameter) array of thin (e.g., 2 mm by 5 mm) LSO crystals mounted on fiber optics that are attached to a position-sensitive photomultiplier, and (2) an external component array 810 of detectors and photomultipliers placed anterior or posterior to the patient.",
"In principle, placing detectors on the ends of fibers has been done before (e.g., for animal scanners), although the motivation in those cases was to allow deployment of large photomultipliers in observing a small volume.",
"Gamma detectors have also been placed on the ends of fiber optics in order to build non-imaging gamma probes.",
"The present inventors have extended these concepts to better suit the needs of endoscopists, by making several enabling modifications, including the following: 1) introducing a quick-release optical fiber coupling so that the detector head is separable from the photomultiplier, and is therefore disposable;",
"2) adding position sensing to the detector head so that events can be correctly placed in sinograms;",
"3) including flexible Monte Carlo-based reconstruction algorithms to allow reconstruction of events from the mobile detector head and a second detector head placed external to the body;",
"and 4) using deterministic sampling to accelerate these reconstruction algorithms.",
"These advantageous features allow the present invention to be useful to surgeons and endoscopists, who can kill or remove cancer or inflammatory cells and then use the present invention to check to ensure that the cells are actually removed or dying.",
"Then, the present invention can be further utilized to check the field of surgery (or other therapy) to determine whether residual viable cells are present, proceeding iteratively to minimize the number of residual viable cells.",
"While the present invention has been described with respect to what is presently considered to be the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments.",
"To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.",
"For example, the above descriptions of embodiments of the invention are primarily couched in terms of using a PET scanner system.",
"Those skilled in the art will understand that a compact gamma camera system using coincidence gating (i.e., a coincident gamma camera system) may also be used.",
"The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.",
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] |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates broadly to a chemical vapor deposition system. More particularly, this invention relates to the injectors and the relationship between the injectors and the nozzle in a plasma jet chemical vapor deposition system for producing diamond films.
2. State of the Art
The utility for high quality thin diamond films for various applications is well known. Superior physical, chemical, and electrical properties make diamond films desirable for many mechanical, thermal, optical and electronic applications. For example, diamond has the highest room-temperature thermal conductivity of any material, a high electric field breakdown (˜10 7 V/cm), and an air stable negative electron affinity. These properties make possible high power, high frequency transistors and cold cathodes, which cannot be made with any semiconductor other than diamond.
One method for producing thin diamond films is by using a chemical vapor deposition (hereinafter `CVD`) system. In CVD systems, a mixture of hydrogen and a gaseous hydrocarbon, such as methane, is activated and contacted with a substrate to produce a diamond film on the substrate. The hydrogen gas is disassociated into atomic hydrogen, which is then reacted with the hydrocarbon to form condensable carbon radicals including elemental carbon. The carbon radicals are then deposited on a substrate to form a diamond film. Some CVD methods use a hot filament, typically at temperatures up to 2000° C., to provide the thermal activation temperatures necessary to bring about the conversion described above. Other CVD methods use a plasma jet.
In some plasma jet methods, hydrogen gas is introduced into a plasma torch which produces a hydrogen plasma jet by means of a direct current arc (hereinafter "DC arc"), or an alternating current arc ("AC arc"), or microwave energy. The plasma torch is hot enough to reduce gases to their elemental form. However, the energy level of the plasma jet has a tendency to fluctuate. One method of stabilizing the energy level of the plasma is to utilize a vortex design in the CVD system. Tangential injection of the hydrogen gas into the arc processor may be used to impart the vortex to the hydrogen, in gaseous and atomic form.
The vortex design results in a controlled swirl of plasma. Hydrogen gas is introduced into the primary jet and some of the hydrogen gas is thereby disassociated into monatomic hydrogen. The hydrogen (in both elemental and molecular states), swirling according to the swirl of the plasma, is forced through a downstream injector system which introduces jets of hydrocarbon needed to react with the elemental hydrogen to form diamond films.
Referring to FIG. 1, a prior art DC arc plasma jet system 10 is shown. The assembly includes a hydrogen gas inlet 12, a cathode 14, a cylindrical chamber 16 having cylindrical walls 17, an anode 18, downstream injectant ports 20a, 20b, a gas injection disc 22 having a plurality of radially-positioned injectors 24a-24h (shown only with respect to 24a and 24b for purposes of clarity), and a nozzle 26 directed toward the substrate. The hydrogen gas enters the hydrogen gas inlet 12 and is heated to a partial plasma state by an arc across the cathode 14 and the anode 18. The arc is controlled by solenoids (not shown) surrounding the chamber. The tangential injection of the hydrogen contains the plasma and imparts the vortex swirl to the plasma. Downstream, hydrocarbon injectant and carrier hydrogen gas enter through the injectant ports 20a, 20b into the gas injection disc 22, and out of the injectors 24a, 24b where the injectant mixes and reacts with the hydrogen plasma, resulting in a mixture of molecular hydrogen, atomic hydrogen and carbon radicals which exits through the nozzle 26.
FIG. 2 illustrates the gas injection disc 22 provided with radially aligned injectors 24a-24h. Each injector is aligned along a radius formed from the periphery of the ring to the center of the ring. Referring to FIG. 3, with reference to one injector 24a, the injector is a substantially cylindrical bore having three portions: a relatively large diameter inlet hole 30, a tapered frustoconical portion 32, and a relatively small diameter outlet hole 34.
There are several known problems associated with state of the art plasma jet systems. For example, various challenges and problems have been encountered with the hydrocarbon injectors. With reference to FIG. 3, a first shortcoming of the prior art injectors is that when using high enthalpy, high energy rate recipes, the injector outlet holes clog. One potential cause of the clogging is that the expanding injected jets entrain atomic hydrogen from the primary jet, bringing atomic hydrogen into the injectors and forming diamond or diamond-like carbon deposits at the outlet hole.
Another problem associated with the injectors of a plasma jet system is that when using a vortex stabilized arc engine, the vortex has a detrimental effect on downstream mixing of the injected hydrocarbon gas. The outer swirl of the vortex consists mainly of molecular hydrogen in equilibrium between the centrifugal force of the swirl and the resultant static pressure gradient throughout the jet. The atomic hydrogen, with half the mass of molecular hydrogen, is drawn towards the center of the swirling jet. Radially injected hydrocarbon, being many times heavier than molecular hydrogen, is forced to the outermost portion of the swirling jet, resulting in a non-uniform mixture of hydrogen and hydrocarbons. Consequently, a diamond film produced from a non-uniform mixture may have a slow growth rate and poor quality.
An additional problem with the use of high enthalpy, high energy rate recipes is that the injectors are subject to excessive heating and are subject to high thermal gradients caused by non-uniform cooling of the injectors at shutdown. The excessive heating and thermal gradient cause the injectors to crack and may further contribute to injector hole clogging. Referring back to FIGS. 1 and 2, two possible causes for the excessive heating of the injectors 24a-24h are direct impingement of recirculated arc gas on the bottom face 22a of the gas injection disc 22, and conduction from the nozzle 26 which is heated by the recirculated gas.
Furthermore, the mixing of downstream injected hydrocarbon gas with a primary flow of swirling hydrogen is a key consideration affecting film growth rate. The flow of hydrocarbon injectant out of the injector is often optimized for mixing with a given flow of hydrogen only by trial and error. However, once a specific injector has been found to give optimum results for a given primary flow of hydrogen it would be desirable to be able to design a hydrocarbon injector which provides the same level of mixing at a different flow rate of injectant through the injector without entering into a new trial and error process.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a plasma jet injection system having an improved injection system for coating diamond films on a substrate.
It is another object of the invention to provide an injection system which has injectors having a reduced likelihood of clogging.
It is a further object of the invention to provide an injection system which has injectors having a reduced likelihood of cracking.
It is an additional object of the invention to provide an injection system which has uniform mixing of primary jet hydrogen and downstream jet hydrocarbons.
It is also an object of the invention to provide a method for designing injectors permitting a predetermined flow of injectant.
In accord with these objects which will be discussed in detail below, a plasma jet CVD system includes a hydrogen gas inlet into a containment chamber, a cathode at the upper portion of the chamber, an anode with a constricted diameter relative to the chamber and located at the lower portion of the chamber, a gas injection disc having injectors in non-radial alignment, a vented stand-off ring, and a nozzle directed toward the substrate. The hydrogen gas enters the hydrogen gas inlet and is heated into a plasma jet by an arc across the cathode and the anode. A tangential injection of the hydrogen gas into the containment chamber contains the plasma and imparts the vortex swirl to the plasma. An injection port introduces hydrocarbon injectant into the injectors of the gas injection disc. According to one aspect of the invention, the injectors are arranged such that they inject hydrocarbon counter-rotational to the vortex swirl. This novel arrangement provides a uniform mixture of hydrocarbon with the hydrogen, resulting in a reactant mixture of atomic hydrogen and carbon radicals. According to another aspect of the invention, each injector has an outlet hole preferably having a flared exit, which keep the holes substantially free from entrained atomic hydrogen. The reactant mixture flows through the stand-off ring and out of the nozzle, where the reactant mixture is deposited onto a substrate located in the fluid path of the nozzle. The stand-off ring effectively creates vents between the gas injection disc and the nozzle, connecting the nozzle to the gas injection disc by four small posts arranged at 90° around the ring. Ambient gas is permitted to enter through the vents. The stand-off ring allows the flowing reactant mixture to draw cooler gases into the nozzle and thereby decreases the formation of recirculation cells at the bottom face of the injector. This prevents hot arc gas from impinging on the injector, and thereby reduces the injector temperature.
In addition, a new method of injector design permits optimal mixing characteristics to be obtained across various hydrogen/hydrocarbon injectant recipes whereby the ratio of the mass flux of the primary flow of the hydrogen jet to the mass flux of the injected flow of hydrocarbon from the downstream injectors is kept constant.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a broken sectional view of the prior art plasma injection system;
FIG. 2 is a top view schematic of the prior art gas injection disc;
FIG. 3 is a broken sectional view of the prior art injector hole design;
FIG. 4 is the broken sectional view of the plasma jet system of the invention;
FIG. 5 is a top view of the gas injection disc assembly of the invention;
FIG. 5A is a section through 5A--5A in FIG. 5;
FIG. 6 is a top view of the gas injection disc according to the invention;
FIG. 6A is a section through 6A--6A in FIG. 6;
FIG. 7 is a side elevational view of the gas injection disc of FIG. 6 rotated by 90°;
FIG. 8 is a top view of a second embodiment of the gas injection disc according to the invention;
FIG. 9 is a top view of a third embodiment of the gas injection disc according to the invention;
FIG. 10 is an enlarged sectional schematic of an injector according to the invention;
FIG. 11 is a top view of a gap ring according to the invention; and
FIG. 11A is a section through 11A--11A in FIG. 11.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 4, a plasma jet system 100 for a plasma jet CVD system includes a hydrogen gas inlet 112 for the passage of hydrogen gas into a containment chamber 116 having an inner wall 117. A cathode 114 is located at the upper portion of the chamber 116. An anode 118 having a constricted diameter relative to the chamber is located at the bottom portion of the chamber. The hydrogen gas enters the hydrogen gas inlet 112 and is heated into a plasma jet by an arc across the cathode 114 and the anode 118. The arc is controlled by a solenoid (not shown) surrounding the containment chamber. The tangential injection of the hydrogen gas and the applied magnetic field contain the plasma and impart a vortex to the plasma. Adjacent the anode 118 is a gas injection disc assembly 119, through which hydrocarbon and carrier hydrogen gas is injected into the plasma swirl, forming a reactant mixture of hydrocarbon and hydrogen. The reactant mixture flows through a stand-off ring 126 and out through a nozzle 128, where a reactant mixture of hydrocarbon and hydrogen is directed toward a substrate 199 located in the path of the nozzle.
Referring to FIGS. 5 and 5A, the gas injection disc assembly 119 includes a gas injection disc 120 and a gas injection disc mounting ring 124. The gas injection disc 120 has a throat 121 and a plurality of injectors 122a-122h organized in an arrangement which is counter-rotational to the swirl of the jet, as explained below. Two injection ports 125a, 125b in the gas injection disc mounting ring 124 introduce hydrocarbon injectant into the injectors 122a-122h, and the injectant is thereby sprayed counter-rotationally to the swirl of the hydrogen jet.
Referring to FIGS. 6, 6A, and 7, the longitudinal axis of each injector 122a-122h is angled off-axis from the radius which runs from an inlet 132a-132h of the injector to the center axis of the gas injection disc 120. The direction of the angular offset is such that the injectors 122a-122h will stream hydrocarbon injectant at an angle opposing the swirl of the primary jet (indicated by the arrow in FIG. 6), reducing the vortex and providing a more uniform reactant mixture of atomic hydrogen and hydrocarbon. As shown with respect to injector 122h, the offset is preferably 30° counter-rotational to the swirl. Compared to radial-type injectors, this design significantly increases the amount of injectant reaching the center of the jet compared to prior art radial injectors. Consequently, at the same flow rates, diamond growth rates have been found to increase by 25% compared to radial-type injectors. In addition, as seen in FIG. 6A, the injectors 122a-h are also preferably angled toward a bottom surface 127 of the gas injector disc 120 by 5° from a line normal to the center axis of the gas injector disc 120.
Turning to FIG. 8, in a second embodiment (with numbers increased by 100 referring to like parts of the first embodiment) the injectors 222a-h may be kept in radial arrangement with only the outlet holes 236a-h counter-rotationally angled off-axis.
Referring to FIG. 9, in third embodiment (with numbers increased by 200 referring to like parts of the first embodiment) the injectors 322a-h may be organized alternatingly in radial 322a, 322c, 322e, 322g and counter-rotational 322b, 322d, 322f, 322h arrangements.
While the first embodiment of the invention having all injectors arranged to stream injectant counter-rotational to the swirl of the vortex is most preferable, it will be appreciated that each alternate embodiment offers an increase in the uniformity of mixing over the prior art and consequently provides better results than prior art systems.
Turning now to FIG. 10, in accord with another aspect of the invention, each injector 122a-122h (shown with respect to one injector 122a) is a substantially cylindrical bore preferably including three portions: a relatively large diameter inlet hole 132a, a frustoconical portion 134a, and a relatively smaller diameter outlet hole 136a having a flared exit 138a. The flared exit 138a is flared to match the expansion angle of the jet of hydrocarbon exiting the injector 122a. As a result, the boundary layer between the injected jet and the exit hole 138a is reduced and migration of atomic hydrogen into the outlet hole 136a is reduced. A flare of 15° is preferable, based on the observed expansion angle of the injected jet and also having been demonstrated effective through experiment. However, other angles above 0° and up to and including 45° will also provide improved performance over the prior art. Additionally, as the prior art injectors show evidence of clogging at the outlet hole, enlarging the outlet hole increases the useful lifetime of the injector because much more buildup would have to occur before the nominal outlet hole size would be reduced.
The injectors 122a-122h (222a-222h, 322a-322h) can have an outlet hole having a diameter determined according to a new method of design. Once a first injector has been found by trial and error to supply a flow of hydrocarbon injectant into a primary jet of hydrogen such that an optimal level of mixing of hydrocarbon and hydrogen results, a new injector can be designed for a different recipe of hydrocarbon and hydrogen while maintaining the optimal level of mixing even though a different flow of hydrocarbon injectant is used. It has been discovered that if the new injector is designed to keep the mass flux ratio the same as that with the first injector, the new injector will provide the same optimal mixing level as that provided by the first injector. For instance, if for a given primary jet flow Q p an optimal level of mixing has been attained for a downstream injectant flow Q s when using an injector with an outlet hole having a diameter D 1 , an optimal mixing level will also be obtained for a new injectant flow Q sn at the same primary jet flow Q p if the outlet hole diameter is changed such that the new diameter D 2 is determined by D 2 =D 1 (Q sn /Q s ) 1/2 .
Utilizing the new injector design method, it will be appreciated that once an optimally performing injector has been obtained it will be a simple operation to design an injector for an alternate downstream injectant flow by changing only the dimension of the outlet hole diameter.
Turning to FIGS. 11 and 11A, a stand-off ring 126 is provided. The stand-off ring is a high temperature alloy ring, preferably made of TZM Mo alloy, which includes a planar surface 148 on a first side and four posts 152a-152d offset by 90° around the ring on a second side. Referring back to FIG. 4, the standoff ring 126 is coupled to the gas injection disc 120 and the nozzle 128 such that the planar surface 148 abuts the gas injection disc 120 and the posts 152a-152d are seated against the nozzle 128. The spaces between the posts 152a-152d act as vents 154a-154d, and the flow of reactant mixture exiting the nozzle draws cooler ambient gas through the vents into the nozzle.
It will be appreciated that the stand-off ring 126 serves three cooling purposes. First, the stand-off ring prevents direct conduction of heat from the nozzle 128 to the injectors 122a-h. Second, the vents 154a-154d allow cooler gas to be drawn into the injector/nozzle area, cooling the injectors 122a-h and creating a layer of cool gas over the inside wall 158 of the nozzle 128. Third, the stand-off ring 126 decouples the gas injection disc 120, which has a relatively small surface area, from the nozzle 128, which has a relatively large surface area, so that upon cooldown the injectors 122a-h are subject to a decreased temperature gradient. Stand-off rings from 1/16 inch to 5/8 inch have been found to result in a gas injection disc temperature drop of approximately 200° C. when used with high heat hydrogen/hydrocarbon recipes.
It will also be appreciated that the stand-off ring 126 increases the deposition rate of the diamond film. The hot gas leaving the throat 121 of the gas injection disc 120 and entering into the larger volume of the nozzle 128 creates a low pressure region at the top of the nozzle (the Venturi effect). The low pressure region normally draws cooler gas in from the bottom of the nozzle. The cool gas being drawn up into the nozzle creates a shear region around the hot jet, causing it to spread. By introducing vents, the cool gas can now be drawn from the top of the nozzle and the amount of shear is reduced. As a result, the jet does not expand as much and therefore travels with greater velocity until it interacts with the boundary layer above the substrate. Because of the increased velocity, the boundary layer thickness is reduced, which results in an increased deposition rate.
There have been described and illustrated herein a plasma jet CVD system having several novel design elements and also a novel method of designing a hydrocarbon injector for an arc processor. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while eight injectors have been disclosed with respect to the gas injection disc, it will be appreciated that fewer or more injectors may be used as well. Furthermore, while a 30° angle is preferable for the counter-rotational angle for the injectors, it will be understood that other angles more than 0° and less than 90° can be used. Also, while the stand-off ring has been disclosed to have a height of from 1/16 inch to 5/8 inch, it will be appreciated that a stand-off ring having another width may also be used. In addition, while several embodiments of the gas injection disc have been disclosed, wherein each embodiment shows an alternate organization of the injectors, it will be appreciated that a gas injection disc may be used which incorporates a combination of the illustrated arrangements. Moreover, it will be appreciated that while the invention has been disclosed with respect to a DC arc plasma jet system incorporating several novel features, it will be recognized that another type of plasma jet system, i.e., radio frequency or microwave, may utilize the novel features disclosed herein. Furthermore, a plasma jet system may be designed which selectively incorporates any one or more of the novel features. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed. | A plasma jet CVD system includes gas injectors and a stand-off ring. The gas injectors have outlet holes preferably flared to approach the expansion angle of the injected jet, thereby keeping the holes substantially free from entrained atomic hydrogen. The injectors are arranged counter-rotational to the swirl of the primary jet, providing a more uniform mixture of hydrocarbons and atomic hydrogen. The stand-off ring provides vents for cooler gases to enter the nozzle, thereby decreasing the overall temperature of the injectors and decreasing the temperature gradient experienced by the injectors, thereby preventing injector cracking. In addition the vents reduce shear, thereby increasing jet velocity and increasing the deposition rate for the coating. In addition, a new method of injector design permits optimal mixing characteristics to be obtained across various recipes whereby the ratio of the mass flux of the primary flow of the jet to the mass flux of the injected flow from the downstream injectors is kept constant. | Summarize the patent information, clearly outlining the technical challenges and proposed solutions. | [
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention This invention relates broadly to a chemical vapor deposition system.",
"More particularly, this invention relates to the injectors and the relationship between the injectors and the nozzle in a plasma jet chemical vapor deposition system for producing diamond films.",
"State of the Art The utility for high quality thin diamond films for various applications is well known.",
"Superior physical, chemical, and electrical properties make diamond films desirable for many mechanical, thermal, optical and electronic applications.",
"For example, diamond has the highest room-temperature thermal conductivity of any material, a high electric field breakdown (˜10 7 V/cm), and an air stable negative electron affinity.",
"These properties make possible high power, high frequency transistors and cold cathodes, which cannot be made with any semiconductor other than diamond.",
"One method for producing thin diamond films is by using a chemical vapor deposition (hereinafter `CVD`) system.",
"In CVD systems, a mixture of hydrogen and a gaseous hydrocarbon, such as methane, is activated and contacted with a substrate to produce a diamond film on the substrate.",
"The hydrogen gas is disassociated into atomic hydrogen, which is then reacted with the hydrocarbon to form condensable carbon radicals including elemental carbon.",
"The carbon radicals are then deposited on a substrate to form a diamond film.",
"Some CVD methods use a hot filament, typically at temperatures up to 2000° C., to provide the thermal activation temperatures necessary to bring about the conversion described above.",
"Other CVD methods use a plasma jet.",
"In some plasma jet methods, hydrogen gas is introduced into a plasma torch which produces a hydrogen plasma jet by means of a direct current arc (hereinafter "DC arc"), or an alternating current arc ("AC arc"), or microwave energy.",
"The plasma torch is hot enough to reduce gases to their elemental form.",
"However, the energy level of the plasma jet has a tendency to fluctuate.",
"One method of stabilizing the energy level of the plasma is to utilize a vortex design in the CVD system.",
"Tangential injection of the hydrogen gas into the arc processor may be used to impart the vortex to the hydrogen, in gaseous and atomic form.",
"The vortex design results in a controlled swirl of plasma.",
"Hydrogen gas is introduced into the primary jet and some of the hydrogen gas is thereby disassociated into monatomic hydrogen.",
"The hydrogen (in both elemental and molecular states), swirling according to the swirl of the plasma, is forced through a downstream injector system which introduces jets of hydrocarbon needed to react with the elemental hydrogen to form diamond films.",
"Referring to FIG. 1, a prior art DC arc plasma jet system 10 is shown.",
"The assembly includes a hydrogen gas inlet 12, a cathode 14, a cylindrical chamber 16 having cylindrical walls 17, an anode 18, downstream injectant ports 20a, 20b, a gas injection disc 22 having a plurality of radially-positioned injectors 24a-24h (shown only with respect to 24a and 24b for purposes of clarity), and a nozzle 26 directed toward the substrate.",
"The hydrogen gas enters the hydrogen gas inlet 12 and is heated to a partial plasma state by an arc across the cathode 14 and the anode 18.",
"The arc is controlled by solenoids (not shown) surrounding the chamber.",
"The tangential injection of the hydrogen contains the plasma and imparts the vortex swirl to the plasma.",
"Downstream, hydrocarbon injectant and carrier hydrogen gas enter through the injectant ports 20a, 20b into the gas injection disc 22, and out of the injectors 24a, 24b where the injectant mixes and reacts with the hydrogen plasma, resulting in a mixture of molecular hydrogen, atomic hydrogen and carbon radicals which exits through the nozzle 26.",
"FIG. 2 illustrates the gas injection disc 22 provided with radially aligned injectors 24a-24h.",
"Each injector is aligned along a radius formed from the periphery of the ring to the center of the ring.",
"Referring to FIG. 3, with reference to one injector 24a, the injector is a substantially cylindrical bore having three portions: a relatively large diameter inlet hole 30, a tapered frustoconical portion 32, and a relatively small diameter outlet hole 34.",
"There are several known problems associated with state of the art plasma jet systems.",
"For example, various challenges and problems have been encountered with the hydrocarbon injectors.",
"With reference to FIG. 3, a first shortcoming of the prior art injectors is that when using high enthalpy, high energy rate recipes, the injector outlet holes clog.",
"One potential cause of the clogging is that the expanding injected jets entrain atomic hydrogen from the primary jet, bringing atomic hydrogen into the injectors and forming diamond or diamond-like carbon deposits at the outlet hole.",
"Another problem associated with the injectors of a plasma jet system is that when using a vortex stabilized arc engine, the vortex has a detrimental effect on downstream mixing of the injected hydrocarbon gas.",
"The outer swirl of the vortex consists mainly of molecular hydrogen in equilibrium between the centrifugal force of the swirl and the resultant static pressure gradient throughout the jet.",
"The atomic hydrogen, with half the mass of molecular hydrogen, is drawn towards the center of the swirling jet.",
"Radially injected hydrocarbon, being many times heavier than molecular hydrogen, is forced to the outermost portion of the swirling jet, resulting in a non-uniform mixture of hydrogen and hydrocarbons.",
"Consequently, a diamond film produced from a non-uniform mixture may have a slow growth rate and poor quality.",
"An additional problem with the use of high enthalpy, high energy rate recipes is that the injectors are subject to excessive heating and are subject to high thermal gradients caused by non-uniform cooling of the injectors at shutdown.",
"The excessive heating and thermal gradient cause the injectors to crack and may further contribute to injector hole clogging.",
"Referring back to FIGS. 1 and 2, two possible causes for the excessive heating of the injectors 24a-24h are direct impingement of recirculated arc gas on the bottom face 22a of the gas injection disc 22, and conduction from the nozzle 26 which is heated by the recirculated gas.",
"Furthermore, the mixing of downstream injected hydrocarbon gas with a primary flow of swirling hydrogen is a key consideration affecting film growth rate.",
"The flow of hydrocarbon injectant out of the injector is often optimized for mixing with a given flow of hydrogen only by trial and error.",
"However, once a specific injector has been found to give optimum results for a given primary flow of hydrogen it would be desirable to be able to design a hydrocarbon injector which provides the same level of mixing at a different flow rate of injectant through the injector without entering into a new trial and error process.",
"SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a plasma jet injection system having an improved injection system for coating diamond films on a substrate.",
"It is another object of the invention to provide an injection system which has injectors having a reduced likelihood of clogging.",
"It is a further object of the invention to provide an injection system which has injectors having a reduced likelihood of cracking.",
"It is an additional object of the invention to provide an injection system which has uniform mixing of primary jet hydrogen and downstream jet hydrocarbons.",
"It is also an object of the invention to provide a method for designing injectors permitting a predetermined flow of injectant.",
"In accord with these objects which will be discussed in detail below, a plasma jet CVD system includes a hydrogen gas inlet into a containment chamber, a cathode at the upper portion of the chamber, an anode with a constricted diameter relative to the chamber and located at the lower portion of the chamber, a gas injection disc having injectors in non-radial alignment, a vented stand-off ring, and a nozzle directed toward the substrate.",
"The hydrogen gas enters the hydrogen gas inlet and is heated into a plasma jet by an arc across the cathode and the anode.",
"A tangential injection of the hydrogen gas into the containment chamber contains the plasma and imparts the vortex swirl to the plasma.",
"An injection port introduces hydrocarbon injectant into the injectors of the gas injection disc.",
"According to one aspect of the invention, the injectors are arranged such that they inject hydrocarbon counter-rotational to the vortex swirl.",
"This novel arrangement provides a uniform mixture of hydrocarbon with the hydrogen, resulting in a reactant mixture of atomic hydrogen and carbon radicals.",
"According to another aspect of the invention, each injector has an outlet hole preferably having a flared exit, which keep the holes substantially free from entrained atomic hydrogen.",
"The reactant mixture flows through the stand-off ring and out of the nozzle, where the reactant mixture is deposited onto a substrate located in the fluid path of the nozzle.",
"The stand-off ring effectively creates vents between the gas injection disc and the nozzle, connecting the nozzle to the gas injection disc by four small posts arranged at 90° around the ring.",
"Ambient gas is permitted to enter through the vents.",
"The stand-off ring allows the flowing reactant mixture to draw cooler gases into the nozzle and thereby decreases the formation of recirculation cells at the bottom face of the injector.",
"This prevents hot arc gas from impinging on the injector, and thereby reduces the injector temperature.",
"In addition, a new method of injector design permits optimal mixing characteristics to be obtained across various hydrogen/hydrocarbon injectant recipes whereby the ratio of the mass flux of the primary flow of the hydrogen jet to the mass flux of the injected flow of hydrocarbon from the downstream injectors is kept constant.",
"Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a broken sectional view of the prior art plasma injection system;",
"FIG. 2 is a top view schematic of the prior art gas injection disc;",
"FIG. 3 is a broken sectional view of the prior art injector hole design;",
"FIG. 4 is the broken sectional view of the plasma jet system of the invention;",
"FIG. 5 is a top view of the gas injection disc assembly of the invention;",
"FIG. 5A is a section through 5A--5A in FIG. 5;",
"FIG. 6 is a top view of the gas injection disc according to the invention;",
"FIG. 6A is a section through 6A--6A in FIG. 6;",
"FIG. 7 is a side elevational view of the gas injection disc of FIG. 6 rotated by 90°;",
"FIG. 8 is a top view of a second embodiment of the gas injection disc according to the invention;",
"FIG. 9 is a top view of a third embodiment of the gas injection disc according to the invention;",
"FIG. 10 is an enlarged sectional schematic of an injector according to the invention;",
"FIG. 11 is a top view of a gap ring according to the invention;",
"and FIG. 11A is a section through 11A--11A in FIG. 11.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 4, a plasma jet system 100 for a plasma jet CVD system includes a hydrogen gas inlet 112 for the passage of hydrogen gas into a containment chamber 116 having an inner wall 117.",
"A cathode 114 is located at the upper portion of the chamber 116.",
"An anode 118 having a constricted diameter relative to the chamber is located at the bottom portion of the chamber.",
"The hydrogen gas enters the hydrogen gas inlet 112 and is heated into a plasma jet by an arc across the cathode 114 and the anode 118.",
"The arc is controlled by a solenoid (not shown) surrounding the containment chamber.",
"The tangential injection of the hydrogen gas and the applied magnetic field contain the plasma and impart a vortex to the plasma.",
"Adjacent the anode 118 is a gas injection disc assembly 119, through which hydrocarbon and carrier hydrogen gas is injected into the plasma swirl, forming a reactant mixture of hydrocarbon and hydrogen.",
"The reactant mixture flows through a stand-off ring 126 and out through a nozzle 128, where a reactant mixture of hydrocarbon and hydrogen is directed toward a substrate 199 located in the path of the nozzle.",
"Referring to FIGS. 5 and 5A, the gas injection disc assembly 119 includes a gas injection disc 120 and a gas injection disc mounting ring 124.",
"The gas injection disc 120 has a throat 121 and a plurality of injectors 122a-122h organized in an arrangement which is counter-rotational to the swirl of the jet, as explained below.",
"Two injection ports 125a, 125b in the gas injection disc mounting ring 124 introduce hydrocarbon injectant into the injectors 122a-122h, and the injectant is thereby sprayed counter-rotationally to the swirl of the hydrogen jet.",
"Referring to FIGS. 6, 6A, and 7, the longitudinal axis of each injector 122a-122h is angled off-axis from the radius which runs from an inlet 132a-132h of the injector to the center axis of the gas injection disc 120.",
"The direction of the angular offset is such that the injectors 122a-122h will stream hydrocarbon injectant at an angle opposing the swirl of the primary jet (indicated by the arrow in FIG. 6), reducing the vortex and providing a more uniform reactant mixture of atomic hydrogen and hydrocarbon.",
"As shown with respect to injector 122h, the offset is preferably 30° counter-rotational to the swirl.",
"Compared to radial-type injectors, this design significantly increases the amount of injectant reaching the center of the jet compared to prior art radial injectors.",
"Consequently, at the same flow rates, diamond growth rates have been found to increase by 25% compared to radial-type injectors.",
"In addition, as seen in FIG. 6A, the injectors 122a-h are also preferably angled toward a bottom surface 127 of the gas injector disc 120 by 5° from a line normal to the center axis of the gas injector disc 120.",
"Turning to FIG. 8, in a second embodiment (with numbers increased by 100 referring to like parts of the first embodiment) the injectors 222a-h may be kept in radial arrangement with only the outlet holes 236a-h counter-rotationally angled off-axis.",
"Referring to FIG. 9, in third embodiment (with numbers increased by 200 referring to like parts of the first embodiment) the injectors 322a-h may be organized alternatingly in radial 322a, 322c, 322e, 322g and counter-rotational 322b, 322d, 322f, 322h arrangements.",
"While the first embodiment of the invention having all injectors arranged to stream injectant counter-rotational to the swirl of the vortex is most preferable, it will be appreciated that each alternate embodiment offers an increase in the uniformity of mixing over the prior art and consequently provides better results than prior art systems.",
"Turning now to FIG. 10, in accord with another aspect of the invention, each injector 122a-122h (shown with respect to one injector 122a) is a substantially cylindrical bore preferably including three portions: a relatively large diameter inlet hole 132a, a frustoconical portion 134a, and a relatively smaller diameter outlet hole 136a having a flared exit 138a.",
"The flared exit 138a is flared to match the expansion angle of the jet of hydrocarbon exiting the injector 122a.",
"As a result, the boundary layer between the injected jet and the exit hole 138a is reduced and migration of atomic hydrogen into the outlet hole 136a is reduced.",
"A flare of 15° is preferable, based on the observed expansion angle of the injected jet and also having been demonstrated effective through experiment.",
"However, other angles above 0° and up to and including 45° will also provide improved performance over the prior art.",
"Additionally, as the prior art injectors show evidence of clogging at the outlet hole, enlarging the outlet hole increases the useful lifetime of the injector because much more buildup would have to occur before the nominal outlet hole size would be reduced.",
"The injectors 122a-122h (222a-222h, 322a-322h) can have an outlet hole having a diameter determined according to a new method of design.",
"Once a first injector has been found by trial and error to supply a flow of hydrocarbon injectant into a primary jet of hydrogen such that an optimal level of mixing of hydrocarbon and hydrogen results, a new injector can be designed for a different recipe of hydrocarbon and hydrogen while maintaining the optimal level of mixing even though a different flow of hydrocarbon injectant is used.",
"It has been discovered that if the new injector is designed to keep the mass flux ratio the same as that with the first injector, the new injector will provide the same optimal mixing level as that provided by the first injector.",
"For instance, if for a given primary jet flow Q p an optimal level of mixing has been attained for a downstream injectant flow Q s when using an injector with an outlet hole having a diameter D 1 , an optimal mixing level will also be obtained for a new injectant flow Q sn at the same primary jet flow Q p if the outlet hole diameter is changed such that the new diameter D 2 is determined by D 2 =D 1 (Q sn /Q s ) 1/2 .",
"Utilizing the new injector design method, it will be appreciated that once an optimally performing injector has been obtained it will be a simple operation to design an injector for an alternate downstream injectant flow by changing only the dimension of the outlet hole diameter.",
"Turning to FIGS. 11 and 11A, a stand-off ring 126 is provided.",
"The stand-off ring is a high temperature alloy ring, preferably made of TZM Mo alloy, which includes a planar surface 148 on a first side and four posts 152a-152d offset by 90° around the ring on a second side.",
"Referring back to FIG. 4, the standoff ring 126 is coupled to the gas injection disc 120 and the nozzle 128 such that the planar surface 148 abuts the gas injection disc 120 and the posts 152a-152d are seated against the nozzle 128.",
"The spaces between the posts 152a-152d act as vents 154a-154d, and the flow of reactant mixture exiting the nozzle draws cooler ambient gas through the vents into the nozzle.",
"It will be appreciated that the stand-off ring 126 serves three cooling purposes.",
"First, the stand-off ring prevents direct conduction of heat from the nozzle 128 to the injectors 122a-h.",
"Second, the vents 154a-154d allow cooler gas to be drawn into the injector/nozzle area, cooling the injectors 122a-h and creating a layer of cool gas over the inside wall 158 of the nozzle 128.",
"Third, the stand-off ring 126 decouples the gas injection disc 120, which has a relatively small surface area, from the nozzle 128, which has a relatively large surface area, so that upon cooldown the injectors 122a-h are subject to a decreased temperature gradient.",
"Stand-off rings from 1/16 inch to 5/8 inch have been found to result in a gas injection disc temperature drop of approximately 200° C. when used with high heat hydrogen/hydrocarbon recipes.",
"It will also be appreciated that the stand-off ring 126 increases the deposition rate of the diamond film.",
"The hot gas leaving the throat 121 of the gas injection disc 120 and entering into the larger volume of the nozzle 128 creates a low pressure region at the top of the nozzle (the Venturi effect).",
"The low pressure region normally draws cooler gas in from the bottom of the nozzle.",
"The cool gas being drawn up into the nozzle creates a shear region around the hot jet, causing it to spread.",
"By introducing vents, the cool gas can now be drawn from the top of the nozzle and the amount of shear is reduced.",
"As a result, the jet does not expand as much and therefore travels with greater velocity until it interacts with the boundary layer above the substrate.",
"Because of the increased velocity, the boundary layer thickness is reduced, which results in an increased deposition rate.",
"There have been described and illustrated herein a plasma jet CVD system having several novel design elements and also a novel method of designing a hydrocarbon injector for an arc processor.",
"While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise.",
"Thus, while eight injectors have been disclosed with respect to the gas injection disc, it will be appreciated that fewer or more injectors may be used as well.",
"Furthermore, while a 30° angle is preferable for the counter-rotational angle for the injectors, it will be understood that other angles more than 0° and less than 90° can be used.",
"Also, while the stand-off ring has been disclosed to have a height of from 1/16 inch to 5/8 inch, it will be appreciated that a stand-off ring having another width may also be used.",
"In addition, while several embodiments of the gas injection disc have been disclosed, wherein each embodiment shows an alternate organization of the injectors, it will be appreciated that a gas injection disc may be used which incorporates a combination of the illustrated arrangements.",
"Moreover, it will be appreciated that while the invention has been disclosed with respect to a DC arc plasma jet system incorporating several novel features, it will be recognized that another type of plasma jet system, i.e., radio frequency or microwave, may utilize the novel features disclosed herein.",
"Furthermore, a plasma jet system may be designed which selectively incorporates any one or more of the novel features.",
"It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed."
] |
BACKGROUND OF THE INVENTION
This invention relates to the field of nondestructive testing, and especially the technique of electronic shearography. The invention comprises an improvement in the electronic circuitry used in shearography.
In the technique of shearing interferometry, or "shearography", two laterally-displaced images of the same object are made to interfere to form an interference pattern called a shearogram. The term "shearing" is used because of the lateral displacement of the interfering images. A first shearogram is taken while the object is in an unstressed condition, and another shearogram is taken when the object is stressed. Comparison of the two shearograms reveals information about the strain concentrations (and hence the integrity) of the object.
In the technique called "electronic shearography", the shearograms are stored in a computer memory, and are compared electronically to produce a composite pattern. Because all the data are processed electronically, the results of the analysis can be viewed in "real time".
U.S. Pat. No. 4,887,899 describes an apparatus and method for performing electronic shearography. In the apparatus shown in the cited patent, a shearogram is produced by passing light, reflected from the test object, through a birefringent material and a polarizer. The birefringent material, which can be a calcite crystal, splits a light ray, reflected from a point on the object, into two rays, and the polarizer makes it possible for these rays to interfere with each other. Thus, each point on the object generates two rays, and the result is a shearogram, i.e. an interference pattern formed by the optical interference of two laterally-displaced images of the same object.
It turns out that the spatial frequency of the shearogram produced with this arrangement is relatively low, because the effective angles between the interfering rays are small. Thus, the shearograms can be recorded by a video camera, which normally has much less resolving capability than a high-density photographic film. By storing the shearogram of the object in its initial, unstressed condition, and by comparing that shearogram, virtually instantaneously, by computer, with further shearograms taken under varying levels of stress, a "real time" image of the resultant strains on the object can be observed.
The above-described method can be practiced by storing the shearograms in separate frame buffers, and by using a real-time video subtractor to perform the comparison. Other methods of comparing the stored shearograms can also be used, as described in the above-cited patent. The amplified output of the subtractor is what is observed on a video display.
Each point on the actual shearogram is generated by the interference of light emanating from a pair of distinct points on the object. Thus, each pixel of the video camera is illuminated by light reflected from those two points. If the overall illumination remains constant, then any variations in the pixel intensity, in the shearogram, will be due only to changes in the phase relationship of the two points of light.
When the initial video image is stored, an initial intensity for each pixel is recorded, as described above. If any differential deformations occur in the object, such deformations will cause changes in the subsequent shearogram. In particular, the intensity of a given pixel will have changed according to the change in the phase relationship between the two rays of light (reflected from two points on the object) which illuminate the pixel. These phase differences can be either positive changes, causing the pixel to become brighter, or negative changes, causing the pixel to become darker. Whether the pixel becomes brighter or darker depends on the initial phase relationship and the direction of the change of phase. Due to the cyclic nature of phase interference, as the deformation of the object continually increases, the intensity at a given pixel will pass through a complete cycle. That is, the intensity at the pixel might increase to a maximum (positive) difference, then return to the original intensity, and then continue to a maximum (negative) difference, and so on.
In the systems of the prior art, only the positive-going variations appearing at the output of the subtractor (or other means of comparison) have been amplified. Thus, in the prior art, the negative-going changes are lost. That is, essentially half of the collected data are lost. The present invention provides an apparatus and method which avoids this waste of data, and thereby greatly improves the resolution of images obtained from electronic shearography.
SUMMARY OF THE INVENTION
In the present invention, a rectifier circuit is placed between the subtraction (or other comparison) circuit in an electronic shearography apparatus, and the amplifier which drives the video display. The rectifier causes all changes in the video signal to go positive. Thus, if the video signal has changed due to deformation of a point on the test object, then the corresponding pixel on the video monitor will be brighter than black, its brightness being proportional to the absolute value of change in the video signal. If the video signal has not changed due to deformation of the given point, then the corresponding pixel on the video monitor will remain black.
The video sync signals are adjusted such that when the input video signal is zero, i.e. when there is no change, between the two shearograms, at a given pixel, the pixel is displayed as black. Thus, all deviations from exact equality of corresponding pixels of different shearograms will be shown, in the final display, as varying levels of brightness, in a range from black to white.
The present invention can be practiced by one of three possible methods. Two of these methods are implemented in hardware. In the first hardware method, the rectifier is an analog circuit comprising a fullwave rectifier. In the second hardware method, the rectifier has a binary (but analog) output. In the latter case, whenever the input pixel represents no change between the shearograms, the output of the rectifier is "zero". When there is some change between the shearograms, the output of the rectifier is "one".
The third method of practicing the invention is to implement one or the other of the above techniques by software.
It is therefore an object of the invention to improve the resolution of an image obtained by electronic shearography.
It is another object to cause all changes in pixel intensity, due to stress on a test object, whether those changes are positive or negative, to be displayed on a video screen.
It is another object to improve the efficiency of electronic shearography.
It is another object to provide various means of enhancing the quality of a video signal produced by electronic shearography, wherein these means can be chosen according to the manner of deformation of the test object.
Other objects and advantages of the invention will be apparent to those skilled in the art, from a reading of the following brief description of the drawings, the detailed description of the invention, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram showing an apparatus for practicing electronic shearography, and illustrates the context in which the present invention is used.
FIGS. 2a and 2b are diagrams of a video signal, obtained by electronic shearography, before and after amplification according to the techniques of the prior art.
FIGS. 3a and 3b are diagrams similar to those of FIG. 2, but showing the effect of the use of the present invention.
FIG. 4 is a block diagram of a circuit of the prior art, the circuit being used to compare two shearograms and to provide a video signal representing the results of the comparison.
FIG. 5 is a block diagram similar to FIG. 4, showing the inclusion of a rectifier circuit, according to the present invention.
FIG. 6 is a schematic and block diagram showing an analog rectifier circuit according to the present invention.
FIG. 7 is a schematic and block diagram showing a digital rectifier circuit according to another embodiment of the present invention.
FIG. 8 is a flow chart illustrating the implementation of the present invention in software.
DETAILED DESCRIPTION OF THE INVENTION
Before explaining the details of the present invention, it is helpful to review the basic concepts of electronic shearography. More details of electronic shearography are given in U.S. Pat. No. 4,887,899, the disclosure of which is incorporated by reference herein.
FIG. 1 is a block diagram showing an arrangement for practicing electronic shearography. Coherent light from laser 1 is directed through fiber optic cable 3 to an illuminator 5, which directs the light onto test object 7. Light is reflected from the object and into shearography camera 9, which includes an optical element 11 for generating a sheared image, a lens 13 for focusing the light, and a video detector 15 (which can be a charge-coupled device, or other photosensitive detection means). In the above-cited patent, the optical element includes a birefringent material and a polarizer, but the present invention is not necessarily limited to the latter type of optical element.
The output of video detector 15 is connected to an image processor 17. The image processor includes a computer 19, and the computer is connected to memory buffers 21 and 23. The buffers can be part of the memory of the computer, and are sufficiently large to be able to store an entire image obtained from detector 15. The computer is also connected to video monitor 25.
In operation, coherent light is reflected from the test object, and two laterally-displaced, or "sheared", images are formed on the video detector 15 of camera 9. These images interfere to form a pattern known as a shearogram. The first shearogram is normally taken while the object is in an unstressed condition, and is digitized and stored in buffer 21. Then, the object is stressed, such as by applying pressure or vacuum, or by other means. Another shearogram is taken in the same way, and the result is stored in buffer 23. The images stored in buffers 21 and 23 are then compared, in the computer. This comparison step typically comprises subtracting one image from the other, but other means of comparison, such as those described in the cited patent, can be used. The result of the subtraction, or other comparison, forms a composite pattern which is displayed on the monitor.
Because the steps are performed with the aid of a computer, the process can be performed in "real time". In particular, one can take repeated shearograms of the object, under varying conditions of stress, and continually compare the most recently obtained shearogram with the initial shearogram, which was taken while the object was not stressed. The result, seen on the monitor, is a "real time" image of the object, showing changes in the object which result from the deformation.
The summary given above is not intended to limit the invention to use with systems exactly as described. Many variations can be made. For example, the particular optical element can be changed, and the manner of directing coherent light onto the object can be different. Also, it is understood that the term "subtraction", when used in this specification to describe the comparison of shearograms, is also meant to include any other methods of comparison.
FIGS. 4 and 5 illustrate the basic difference between a shearography system of the prior art and that of the present invention. In a system of the prior art, represented by FIG. 4, a video signal, containing a shearogram, is passed through analog-to-digital converter 31, and then either into buffer 33 or buffer 35. It is understood that an appropriate control circuit, not shown in FIG. 4, channels the output of converter 31 into one of the buffers 33 and 35. The contents of the buffers are converted to analog signals, by converters 37 and 39. These analog signals are compared, such as by direct subtraction, by operational amplifier 41. The resulting signal is amplified by amplifier 43, and drives a video monitor.
The arrangement of FIG. 5 is similar to that of FIG. 4, with the exception that rectifier 45 is inserted between the last two amplifiers. The rectifier thus receives the subtracted (or otherwise compared) video signal, as its input, and passes a signal to the final amplifier which drives the video monitor.
The operations of the circuits shown in FIGS. 4 and 5 are represented by the diagrams of FIGS. 2 and 3, respectively. FIG. 2(a) illustrates a typical video signal resulting from the subtraction of two shearograms by amplifier 41. This signal includes sync (video synchronization) pulse 51 and the actual video signal 53. Because signal 53 represents a comparison of two images that are, in general, very similar, the amplitude of the variations of signal 53 is normally very small.
When the signal 53 is amplified by amplifier 43, the result is effectively what is shown in FIG. 2(b). Because the black level is assumed to be set at approximately the level indicated by reference numeral 55, the portion of the signal which goes below the black level is lost. Only that part of the signal which extends above the black level will result in a visible pixel. Thus, the quality of the image is relatively poor, as approximately half of the information in the video signal is discarded.
The problem described above cannot be solved simply by moving the black level downward. The variations comprising signal 53 originate from small phase changes due to deformation of the object. These phase changes can be either positive or negative. If one designated the lowest value of signal 53 as "black", the resulting image would be difficult to interpret, since the condition representing "no change" would appear not as black, but as halfway between black and white. An image in which the points of "no change" appear as black is much easier to interpret. The present invention achieves the latter result, while preserving the full dynamic range, i.e. wherein the changes in the video signal can range from full black to full white.
FIG. 3 shows the effect of the circuit of the present invention. FIG. 3(a) represents the subtracted video signal, similar to that of FIG. 2(a). However, in this case, the subtracted signal is fed to rectifier 45. FIG. 3(b) shows the output of the amplifier which follows the rectifier. Reference numeral 57 denotes the "black" level, and arrow 59 denotes the full "white" level. Note, therefore, that both the positive-going and negative-going changes in the subtracted video signal produce signals within the region between black and white. The signal is black only when the subtracted signal is zero, i.e. when there is no change, at the given pixel, between the shearograms being compared. Thus, all of the changes in the image, due to deformation of the test object, can be observed in the resulting display; none of the data are lost.
FIG. 6 is a schematic and block diagram of a rectifier circuit according to one embodiment of the invention. The circuit of FIG. 6 comprises an analog implementation of the invention. This circuit is what is represented by block 45 in FIG. 5.
In the circuit of FIG. 6, the subtracted video signal is applied to sync stripper 61. The sync stripper is essentially an electronic switch which directs output to line 63 during the video portion of the signal, and which directs output to line 65 during the sync portion of the signal. Thus, sync stripper 61 resolves the incoming signal into two signals, one containing only the video information and the other containing only the sync pulses. A conventional timing and control circuit is assumed to be part of the sync stripper, and is not explicitly shown.
The video output on line 63 is connected to amplifier 66. The video signal normally needs amplification because it represents the subtraction (or other comparison) of two signals which comprise images of the same object, and are usually very similar. Thus, the amplitude of the video signal is usually very small.
The amplified signal is connected to CMOS switch 67. The CMOS switch is closed during the time that the video signal is present, and is open during the time when the sync pulse would have been present (if it had not been removed). The purpose of this switch is to eliminate the electrical noise or transients which may be introduced by the stripper circuit. The switch can comprise one or more CMOS transistors or equivalent. A conventional timing and control circuit, similar to, or the same as, that which controls the stripper, is also included to operate the CMOS switch, and is not explicitly shown.
The CMOS switch can be omitted. It is only necessary where the sync stripper generates significant amount of noise. Thus, the CMOS switch is not essential to the basic operation of the invention.
The resulting signal is ac-coupled, such as by capacitor 69, to amplifier 71. The capacitor eliminates any dc component in the signal.
The signal is then connected to the components which perform the actual rectification. Operational amplifier 73 receives the amplified video signal, and the output of this amplifier is connected in parallel to diodes 75 and 77, which have opposite polarities. The outputs of the diodes are combined in amplifier 79, which functions as an adder. The output of amplifier 79 is thus a rectified signal. The latter statement is true because, when the signal applied to amplifier 73 is positive-going, one of the diodes conducts and the other is cut off, and when the signal is negative-going, the other diode conducts and the first one is cut off. Thus, amplifier 79 receives an input every time there is a change, either positive or negative, in the video signal.
The output of amplifier 79 is recombined with the sync pulses, in amplifier 81, to produce a signal that can be used to drive the video monitor.
FIG. 7 illustrates another embodiment of the invention, wherein the rectification is performed with another analog circuit having a binary output. As in the embodiment of FIG. 6, the subtracted video signal is separated from the sync pulses by stripper 91, and is amplified by amplifier 95. The resulting signal is then ac-coupled, in parallel, to comparators 97 and 99. The comparators are configured such that any negative-going signal will generate a positive pulse in comparator 97 (labeled "NEG"), and will produce no output in comparator 99. Similarly, any positive-going signal will produce a positive pulse in comparator 99 (labeled "POS"), and yields no output in comparator 97. The comparators produce pulses of uniform amplitude, irrespective of the amplitude of the incoming signals. The outputs of the comparators 97 and 99 are combined with the sync signal, in amplifier 101, the output of which drives the video monitor.
The embodiment of FIG. 7 is useful when one needs a quick indication of the status of the test object, and when one is not particularly concerned about a fine-quality image. Such a technique is especially useful where the object is stressed acoustically or by direct mechanical vibration. On the other hand, the embodiment of FIG. 6 is more suitable if the object is stressed by vacuum or pressure. In the latter case, one can more accurately control the precise amount of stress applied to the object, and it is meaningful to seek more detailed information about the condition of the object.
Both the embodiments of FIG. 6 and FIG. 7 can be implemented in software. FIG. 8 is a flow chart illustrating the essential steps of such software. The system starts by obtaining the analog video signal, in block 200. The latter step is not part of the software, but represents the interface between analog and digital portions of the system. The system sets the input gain in block 201. The gain is determined by the value of a variable in the program. This step can be made part of the software, or it can be an analog control.
Next, the program "grabs" the first frame, in block 203, and the second frame, in block 205. Blocks 203 and 205 therefore represent the digitizing steps. The video signal is typically digitized on a scale of zero to 256, with zero being black and 256 being white, although other digitizing schemes are possible.
In block 207, the program performs the subtraction. This is a pixel-by-pixel subtraction. Thus, if two corresponding pixels are equal, the result of the subtraction would be zero. However, the program adds 128 to the result of each subtraction, so that points of "no change" have the pixel value 128.
Each pixel is compared with 128, in test 209. If the pixel value is less than 128, the program sets the pixel value equal to 256 minus the pixel value, in block 210. If the pixel value is greater than or equal to 128, the program sets the pixel value equal to the pixel value minus 128, in block 211. It is understood that the operations represented by test 209, and blocks 210 or 211, are performed individually for all the pixels in the frame.
The pixel values are "normalized" in block 212. Block 212 represents a subroutine which determines the highest and lowest pixel values in the frame, and which sets these extreme values to 256 and zero, respectively. The normalization subroutine also adjusts the intermediate values according to the scale defined by the extreme values.
The normalized set of pixels is stored in a new frame, in block 213. The system sets various output parameters (such as output gain and/or color), in block 215, and also converts the data into an analog video signal. The result is connected to the video monitor, in block 217, the latter block representing an analog step.
In the software implementation shown in FIG. 8, the rectification of the subtracted video signal is performed by the procedure represented by test 209 and blocks 210 and 211.
The software technique has the advantage that it can be easily modified to obtain varying results. For example, the "gain" of the rectifier circuit, or other parameters such as DC offset, can be easily changed by setting a variable in a program. This advantage is particularly helpful in system development. On the other hand, typically the computer operating the program is not sufficiently fast, and the procedure of FIG. 8 will not operate in "real time". The latter disadvantage can be overcome by using faster or dedicated processors.
Of course, variations on the program shown in FIG. 8 are possible. The video signal can be digitized according to a different scale. The means of comparison of the frames can be other than simple subtraction. Also, the signal could be digitized after subtraction, instead of before the subtraction step.
Other modifications can be made in the analog and digital implementations. The present invention is not limited by the means of performing electronic shearography. Various circuit arrangements can be used to implement the rectifier shown in block 45 of FIG. 5. The particular arrangements of FIGS. 6 and 7 are intended to be exemplary, and not limiting. All of the above modifications are intended to be included within the spirit and scope of the following claims. | The purpose of the present invention is to improve the quality of a video signal generated by the method of nondestructive testing known as electronic shearography. In electronic shearography, two laterally-displaced images of a test object are made to interfere, and the interference pattern is stored. Another such interference pattern is obtained while the object is stressed. The two patterns are compared by computer, such as by subtracting one pattern from the other, and the resulting composite pattern is displayed on a video monitor or equivalent. According to the present invention, the subtracted signal is connected to a rectifier circuit which causes both positive-going and negative-going variations in the video signal to become positive-going variations. Thus, any changes in the intensity of the signal, due to phase changes resulting from deformation of the object, are displayed as increases in brightness of a pixel on the final display. If a point on the object has not moved due to the applied stress, the pixels representing that point remain dark. The present invention therefore produces an image having a greater resolution than is possible using the methods of the prior art. | Provide a concise summary of the essential information conveyed in the given context. | [
"BACKGROUND OF THE INVENTION This invention relates to the field of nondestructive testing, and especially the technique of electronic shearography.",
"The invention comprises an improvement in the electronic circuitry used in shearography.",
"In the technique of shearing interferometry, or "shearography", two laterally-displaced images of the same object are made to interfere to form an interference pattern called a shearogram.",
"The term "shearing"",
"is used because of the lateral displacement of the interfering images.",
"A first shearogram is taken while the object is in an unstressed condition, and another shearogram is taken when the object is stressed.",
"Comparison of the two shearograms reveals information about the strain concentrations (and hence the integrity) of the object.",
"In the technique called "electronic shearography", the shearograms are stored in a computer memory, and are compared electronically to produce a composite pattern.",
"Because all the data are processed electronically, the results of the analysis can be viewed in "real time".",
"U.S. Pat. No. 4,887,899 describes an apparatus and method for performing electronic shearography.",
"In the apparatus shown in the cited patent, a shearogram is produced by passing light, reflected from the test object, through a birefringent material and a polarizer.",
"The birefringent material, which can be a calcite crystal, splits a light ray, reflected from a point on the object, into two rays, and the polarizer makes it possible for these rays to interfere with each other.",
"Thus, each point on the object generates two rays, and the result is a shearogram, i.e. an interference pattern formed by the optical interference of two laterally-displaced images of the same object.",
"It turns out that the spatial frequency of the shearogram produced with this arrangement is relatively low, because the effective angles between the interfering rays are small.",
"Thus, the shearograms can be recorded by a video camera, which normally has much less resolving capability than a high-density photographic film.",
"By storing the shearogram of the object in its initial, unstressed condition, and by comparing that shearogram, virtually instantaneously, by computer, with further shearograms taken under varying levels of stress, a "real time"",
"image of the resultant strains on the object can be observed.",
"The above-described method can be practiced by storing the shearograms in separate frame buffers, and by using a real-time video subtractor to perform the comparison.",
"Other methods of comparing the stored shearograms can also be used, as described in the above-cited patent.",
"The amplified output of the subtractor is what is observed on a video display.",
"Each point on the actual shearogram is generated by the interference of light emanating from a pair of distinct points on the object.",
"Thus, each pixel of the video camera is illuminated by light reflected from those two points.",
"If the overall illumination remains constant, then any variations in the pixel intensity, in the shearogram, will be due only to changes in the phase relationship of the two points of light.",
"When the initial video image is stored, an initial intensity for each pixel is recorded, as described above.",
"If any differential deformations occur in the object, such deformations will cause changes in the subsequent shearogram.",
"In particular, the intensity of a given pixel will have changed according to the change in the phase relationship between the two rays of light (reflected from two points on the object) which illuminate the pixel.",
"These phase differences can be either positive changes, causing the pixel to become brighter, or negative changes, causing the pixel to become darker.",
"Whether the pixel becomes brighter or darker depends on the initial phase relationship and the direction of the change of phase.",
"Due to the cyclic nature of phase interference, as the deformation of the object continually increases, the intensity at a given pixel will pass through a complete cycle.",
"That is, the intensity at the pixel might increase to a maximum (positive) difference, then return to the original intensity, and then continue to a maximum (negative) difference, and so on.",
"In the systems of the prior art, only the positive-going variations appearing at the output of the subtractor (or other means of comparison) have been amplified.",
"Thus, in the prior art, the negative-going changes are lost.",
"That is, essentially half of the collected data are lost.",
"The present invention provides an apparatus and method which avoids this waste of data, and thereby greatly improves the resolution of images obtained from electronic shearography.",
"SUMMARY OF THE INVENTION In the present invention, a rectifier circuit is placed between the subtraction (or other comparison) circuit in an electronic shearography apparatus, and the amplifier which drives the video display.",
"The rectifier causes all changes in the video signal to go positive.",
"Thus, if the video signal has changed due to deformation of a point on the test object, then the corresponding pixel on the video monitor will be brighter than black, its brightness being proportional to the absolute value of change in the video signal.",
"If the video signal has not changed due to deformation of the given point, then the corresponding pixel on the video monitor will remain black.",
"The video sync signals are adjusted such that when the input video signal is zero, i.e. when there is no change, between the two shearograms, at a given pixel, the pixel is displayed as black.",
"Thus, all deviations from exact equality of corresponding pixels of different shearograms will be shown, in the final display, as varying levels of brightness, in a range from black to white.",
"The present invention can be practiced by one of three possible methods.",
"Two of these methods are implemented in hardware.",
"In the first hardware method, the rectifier is an analog circuit comprising a fullwave rectifier.",
"In the second hardware method, the rectifier has a binary (but analog) output.",
"In the latter case, whenever the input pixel represents no change between the shearograms, the output of the rectifier is "zero".",
"When there is some change between the shearograms, the output of the rectifier is "one".",
"The third method of practicing the invention is to implement one or the other of the above techniques by software.",
"It is therefore an object of the invention to improve the resolution of an image obtained by electronic shearography.",
"It is another object to cause all changes in pixel intensity, due to stress on a test object, whether those changes are positive or negative, to be displayed on a video screen.",
"It is another object to improve the efficiency of electronic shearography.",
"It is another object to provide various means of enhancing the quality of a video signal produced by electronic shearography, wherein these means can be chosen according to the manner of deformation of the test object.",
"Other objects and advantages of the invention will be apparent to those skilled in the art, from a reading of the following brief description of the drawings, the detailed description of the invention, and the appended claims.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an apparatus for practicing electronic shearography, and illustrates the context in which the present invention is used.",
"FIGS. 2a and 2b are diagrams of a video signal, obtained by electronic shearography, before and after amplification according to the techniques of the prior art.",
"FIGS. 3a and 3b are diagrams similar to those of FIG. 2, but showing the effect of the use of the present invention.",
"FIG. 4 is a block diagram of a circuit of the prior art, the circuit being used to compare two shearograms and to provide a video signal representing the results of the comparison.",
"FIG. 5 is a block diagram similar to FIG. 4, showing the inclusion of a rectifier circuit, according to the present invention.",
"FIG. 6 is a schematic and block diagram showing an analog rectifier circuit according to the present invention.",
"FIG. 7 is a schematic and block diagram showing a digital rectifier circuit according to another embodiment of the present invention.",
"FIG. 8 is a flow chart illustrating the implementation of the present invention in software.",
"DETAILED DESCRIPTION OF THE INVENTION Before explaining the details of the present invention, it is helpful to review the basic concepts of electronic shearography.",
"More details of electronic shearography are given in U.S. Pat. No. 4,887,899, the disclosure of which is incorporated by reference herein.",
"FIG. 1 is a block diagram showing an arrangement for practicing electronic shearography.",
"Coherent light from laser 1 is directed through fiber optic cable 3 to an illuminator 5, which directs the light onto test object 7.",
"Light is reflected from the object and into shearography camera 9, which includes an optical element 11 for generating a sheared image, a lens 13 for focusing the light, and a video detector 15 (which can be a charge-coupled device, or other photosensitive detection means).",
"In the above-cited patent, the optical element includes a birefringent material and a polarizer, but the present invention is not necessarily limited to the latter type of optical element.",
"The output of video detector 15 is connected to an image processor 17.",
"The image processor includes a computer 19, and the computer is connected to memory buffers 21 and 23.",
"The buffers can be part of the memory of the computer, and are sufficiently large to be able to store an entire image obtained from detector 15.",
"The computer is also connected to video monitor 25.",
"In operation, coherent light is reflected from the test object, and two laterally-displaced, or "sheared", images are formed on the video detector 15 of camera 9.",
"These images interfere to form a pattern known as a shearogram.",
"The first shearogram is normally taken while the object is in an unstressed condition, and is digitized and stored in buffer 21.",
"Then, the object is stressed, such as by applying pressure or vacuum, or by other means.",
"Another shearogram is taken in the same way, and the result is stored in buffer 23.",
"The images stored in buffers 21 and 23 are then compared, in the computer.",
"This comparison step typically comprises subtracting one image from the other, but other means of comparison, such as those described in the cited patent, can be used.",
"The result of the subtraction, or other comparison, forms a composite pattern which is displayed on the monitor.",
"Because the steps are performed with the aid of a computer, the process can be performed in "real time".",
"In particular, one can take repeated shearograms of the object, under varying conditions of stress, and continually compare the most recently obtained shearogram with the initial shearogram, which was taken while the object was not stressed.",
"The result, seen on the monitor, is a "real time"",
"image of the object, showing changes in the object which result from the deformation.",
"The summary given above is not intended to limit the invention to use with systems exactly as described.",
"Many variations can be made.",
"For example, the particular optical element can be changed, and the manner of directing coherent light onto the object can be different.",
"Also, it is understood that the term "subtraction", when used in this specification to describe the comparison of shearograms, is also meant to include any other methods of comparison.",
"FIGS. 4 and 5 illustrate the basic difference between a shearography system of the prior art and that of the present invention.",
"In a system of the prior art, represented by FIG. 4, a video signal, containing a shearogram, is passed through analog-to-digital converter 31, and then either into buffer 33 or buffer 35.",
"It is understood that an appropriate control circuit, not shown in FIG. 4, channels the output of converter 31 into one of the buffers 33 and 35.",
"The contents of the buffers are converted to analog signals, by converters 37 and 39.",
"These analog signals are compared, such as by direct subtraction, by operational amplifier 41.",
"The resulting signal is amplified by amplifier 43, and drives a video monitor.",
"The arrangement of FIG. 5 is similar to that of FIG. 4, with the exception that rectifier 45 is inserted between the last two amplifiers.",
"The rectifier thus receives the subtracted (or otherwise compared) video signal, as its input, and passes a signal to the final amplifier which drives the video monitor.",
"The operations of the circuits shown in FIGS. 4 and 5 are represented by the diagrams of FIGS. 2 and 3, respectively.",
"FIG. 2(a) illustrates a typical video signal resulting from the subtraction of two shearograms by amplifier 41.",
"This signal includes sync (video synchronization) pulse 51 and the actual video signal 53.",
"Because signal 53 represents a comparison of two images that are, in general, very similar, the amplitude of the variations of signal 53 is normally very small.",
"When the signal 53 is amplified by amplifier 43, the result is effectively what is shown in FIG. 2(b).",
"Because the black level is assumed to be set at approximately the level indicated by reference numeral 55, the portion of the signal which goes below the black level is lost.",
"Only that part of the signal which extends above the black level will result in a visible pixel.",
"Thus, the quality of the image is relatively poor, as approximately half of the information in the video signal is discarded.",
"The problem described above cannot be solved simply by moving the black level downward.",
"The variations comprising signal 53 originate from small phase changes due to deformation of the object.",
"These phase changes can be either positive or negative.",
"If one designated the lowest value of signal 53 as "black", the resulting image would be difficult to interpret, since the condition representing "no change"",
"would appear not as black, but as halfway between black and white.",
"An image in which the points of "no change"",
"appear as black is much easier to interpret.",
"The present invention achieves the latter result, while preserving the full dynamic range, i.e. wherein the changes in the video signal can range from full black to full white.",
"FIG. 3 shows the effect of the circuit of the present invention.",
"FIG. 3(a) represents the subtracted video signal, similar to that of FIG. 2(a).",
"However, in this case, the subtracted signal is fed to rectifier 45.",
"FIG. 3(b) shows the output of the amplifier which follows the rectifier.",
"Reference numeral 57 denotes the "black"",
"level, and arrow 59 denotes the full "white"",
"level.",
"Note, therefore, that both the positive-going and negative-going changes in the subtracted video signal produce signals within the region between black and white.",
"The signal is black only when the subtracted signal is zero, i.e. when there is no change, at the given pixel, between the shearograms being compared.",
"Thus, all of the changes in the image, due to deformation of the test object, can be observed in the resulting display;",
"none of the data are lost.",
"FIG. 6 is a schematic and block diagram of a rectifier circuit according to one embodiment of the invention.",
"The circuit of FIG. 6 comprises an analog implementation of the invention.",
"This circuit is what is represented by block 45 in FIG. 5. In the circuit of FIG. 6, the subtracted video signal is applied to sync stripper 61.",
"The sync stripper is essentially an electronic switch which directs output to line 63 during the video portion of the signal, and which directs output to line 65 during the sync portion of the signal.",
"Thus, sync stripper 61 resolves the incoming signal into two signals, one containing only the video information and the other containing only the sync pulses.",
"A conventional timing and control circuit is assumed to be part of the sync stripper, and is not explicitly shown.",
"The video output on line 63 is connected to amplifier 66.",
"The video signal normally needs amplification because it represents the subtraction (or other comparison) of two signals which comprise images of the same object, and are usually very similar.",
"Thus, the amplitude of the video signal is usually very small.",
"The amplified signal is connected to CMOS switch 67.",
"The CMOS switch is closed during the time that the video signal is present, and is open during the time when the sync pulse would have been present (if it had not been removed).",
"The purpose of this switch is to eliminate the electrical noise or transients which may be introduced by the stripper circuit.",
"The switch can comprise one or more CMOS transistors or equivalent.",
"A conventional timing and control circuit, similar to, or the same as, that which controls the stripper, is also included to operate the CMOS switch, and is not explicitly shown.",
"The CMOS switch can be omitted.",
"It is only necessary where the sync stripper generates significant amount of noise.",
"Thus, the CMOS switch is not essential to the basic operation of the invention.",
"The resulting signal is ac-coupled, such as by capacitor 69, to amplifier 71.",
"The capacitor eliminates any dc component in the signal.",
"The signal is then connected to the components which perform the actual rectification.",
"Operational amplifier 73 receives the amplified video signal, and the output of this amplifier is connected in parallel to diodes 75 and 77, which have opposite polarities.",
"The outputs of the diodes are combined in amplifier 79, which functions as an adder.",
"The output of amplifier 79 is thus a rectified signal.",
"The latter statement is true because, when the signal applied to amplifier 73 is positive-going, one of the diodes conducts and the other is cut off, and when the signal is negative-going, the other diode conducts and the first one is cut off.",
"Thus, amplifier 79 receives an input every time there is a change, either positive or negative, in the video signal.",
"The output of amplifier 79 is recombined with the sync pulses, in amplifier 81, to produce a signal that can be used to drive the video monitor.",
"FIG. 7 illustrates another embodiment of the invention, wherein the rectification is performed with another analog circuit having a binary output.",
"As in the embodiment of FIG. 6, the subtracted video signal is separated from the sync pulses by stripper 91, and is amplified by amplifier 95.",
"The resulting signal is then ac-coupled, in parallel, to comparators 97 and 99.",
"The comparators are configured such that any negative-going signal will generate a positive pulse in comparator 97 (labeled "NEG"), and will produce no output in comparator 99.",
"Similarly, any positive-going signal will produce a positive pulse in comparator 99 (labeled "POS"), and yields no output in comparator 97.",
"The comparators produce pulses of uniform amplitude, irrespective of the amplitude of the incoming signals.",
"The outputs of the comparators 97 and 99 are combined with the sync signal, in amplifier 101, the output of which drives the video monitor.",
"The embodiment of FIG. 7 is useful when one needs a quick indication of the status of the test object, and when one is not particularly concerned about a fine-quality image.",
"Such a technique is especially useful where the object is stressed acoustically or by direct mechanical vibration.",
"On the other hand, the embodiment of FIG. 6 is more suitable if the object is stressed by vacuum or pressure.",
"In the latter case, one can more accurately control the precise amount of stress applied to the object, and it is meaningful to seek more detailed information about the condition of the object.",
"Both the embodiments of FIG. 6 and FIG. 7 can be implemented in software.",
"FIG. 8 is a flow chart illustrating the essential steps of such software.",
"The system starts by obtaining the analog video signal, in block 200.",
"The latter step is not part of the software, but represents the interface between analog and digital portions of the system.",
"The system sets the input gain in block 201.",
"The gain is determined by the value of a variable in the program.",
"This step can be made part of the software, or it can be an analog control.",
"Next, the program "grabs"",
"the first frame, in block 203, and the second frame, in block 205.",
"Blocks 203 and 205 therefore represent the digitizing steps.",
"The video signal is typically digitized on a scale of zero to 256, with zero being black and 256 being white, although other digitizing schemes are possible.",
"In block 207, the program performs the subtraction.",
"This is a pixel-by-pixel subtraction.",
"Thus, if two corresponding pixels are equal, the result of the subtraction would be zero.",
"However, the program adds 128 to the result of each subtraction, so that points of "no change"",
"have the pixel value 128.",
"Each pixel is compared with 128, in test 209.",
"If the pixel value is less than 128, the program sets the pixel value equal to 256 minus the pixel value, in block 210.",
"If the pixel value is greater than or equal to 128, the program sets the pixel value equal to the pixel value minus 128, in block 211.",
"It is understood that the operations represented by test 209, and blocks 210 or 211, are performed individually for all the pixels in the frame.",
"The pixel values are "normalized"",
"in block 212.",
"Block 212 represents a subroutine which determines the highest and lowest pixel values in the frame, and which sets these extreme values to 256 and zero, respectively.",
"The normalization subroutine also adjusts the intermediate values according to the scale defined by the extreme values.",
"The normalized set of pixels is stored in a new frame, in block 213.",
"The system sets various output parameters (such as output gain and/or color), in block 215, and also converts the data into an analog video signal.",
"The result is connected to the video monitor, in block 217, the latter block representing an analog step.",
"In the software implementation shown in FIG. 8, the rectification of the subtracted video signal is performed by the procedure represented by test 209 and blocks 210 and 211.",
"The software technique has the advantage that it can be easily modified to obtain varying results.",
"For example, the "gain"",
"of the rectifier circuit, or other parameters such as DC offset, can be easily changed by setting a variable in a program.",
"This advantage is particularly helpful in system development.",
"On the other hand, typically the computer operating the program is not sufficiently fast, and the procedure of FIG. 8 will not operate in "real time".",
"The latter disadvantage can be overcome by using faster or dedicated processors.",
"Of course, variations on the program shown in FIG. 8 are possible.",
"The video signal can be digitized according to a different scale.",
"The means of comparison of the frames can be other than simple subtraction.",
"Also, the signal could be digitized after subtraction, instead of before the subtraction step.",
"Other modifications can be made in the analog and digital implementations.",
"The present invention is not limited by the means of performing electronic shearography.",
"Various circuit arrangements can be used to implement the rectifier shown in block 45 of FIG. 5. The particular arrangements of FIGS. 6 and 7 are intended to be exemplary, and not limiting.",
"All of the above modifications are intended to be included within the spirit and scope of the following claims."
] |
FIELD
[0001] The present disclosure relates to fuel system control strategies.
BACKGROUND
[0002] This section provides background information related to the present disclosure which is not necessarily prior art.
[0003] Engines may include fuel pressure sensors to determine and control operating pressures therein. After engine shutdown, high pressure fuel systems may bleed fuel from the system through clearances in the fuel injectors. However, some fuel types may have difficulty leaking through the fuel injectors after engine shutdown. This may hinder service of the fuel system due to high pressure being maintained after engine shutdown. Additionally, this may result in longer than expected leak times and may set a false error indicating a pressure sensor failure.
SUMMARY
[0004] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
[0005] A fuel system control method may include determining when an engine transitions from an engine on condition to an engine off condition. The method further includes determining a first fuel pressure in a fuel system of the engine a predetermined time after the determined engine off condition. A fuel injector of the fuel system may be actuated during the engine off condition when the first determined fuel pressure is above a first predetermined pressure limit to bleed fuel from the fuel system and reduce pressure within the fuel system.
[0006] The method may additionally include determining a second fuel pressure in the fuel system after the actuating and indicating a system fault when the second fuel pressure is above a second predetermined pressure limit.
[0007] A control module may include an engine operating condition evaluation module, a fuel pressure determination module, and a fuel injector actuation module. The engine operating condition evaluation module may determine when an engine transitions from an on condition to an off condition. The fuel pressure determination module may be in communication with the engine operating condition evaluation module and may determine a first fuel pressure in a fuel system of the engine a predetermined time after the determined engine off condition. The fuel injector actuation module may be in communication with the fuel pressure determination module and may actuate a fuel injector of the fuel system during the engine off condition when the first determined fuel pressure is above a first predetermined pressure limit to bleed fuel from the fuel system and reduce pressure within the fuel system.
[0008] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
[0009] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
[0010] FIG. 1 is a schematic illustration of an engine assembly according to the present disclosure;
[0011] FIG. 2 is a schematic illustration of a control module of the engine assembly of FIG. 1 ; and
[0012] FIG. 3 is an illustration of control logic for operation of the engine assembly of FIG. 1 .
[0013] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0014] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the term “module” refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, or other suitable components that provide the described functionality.
[0015] Referring to FIG. 1 , an exemplary engine assembly 10 is schematically illustrated. The engine assembly 10 may include an engine 12 in communication with a fuel system 14 and a control module 16 . The engine 12 may include an engine block 18 defining a plurality of cylinders 20 in communication with the fuel system 14 .
[0016] The fuel system 14 may include a fuel tank 22 , a fuel pump 24 , a fuel line 26 , a fuel rail 28 , fuel injectors 30 , and a pressure sensor 32 . The fuel injectors 30 may be in direct communication with the cylinders 20 , forming a direct injection arrangement. More specifically, the engine 12 may be a diesel engine and the fuel tank 22 may store a supply of diesel fuel. The fuel injectors 30 may be solenoid actuated, each including a solenoid 34 in communication with the control module 16 and selectively displacing a valve member (not shown) in the fuel injector 30 to provide a pressurized fuel flow to the cylinders 20 . However, while described with respect to a diesel engine, it is understood that the present disclosure is not limited to diesel applications.
[0017] During operation, the fuel pump 24 may provide a pressurized fuel flow from the fuel tank 22 to the fuel rail 28 via the fuel line 26 . The fuel line 26 and the fuel rail 28 may define a fuel volume (V) between the fuel pump 24 and the fuel injectors 30 . During engine operation, the fuel volume (V) may be maintained at a pressure greater than 30 megapascal (MPa). For example, the pressure within the fuel volume (V) during engine idle conditions may be greater than 30 MPa. The pressure sensor 32 may be in communication with the fuel volume (V) to monitor the fuel pressure. In the present example, the pressure sensor 32 is in communication with the fuel rail 28 and monitors the fuel pressure therein.
[0018] Referring now to FIG. 2 , the control module 16 may include an engine operating condition evaluation module 36 , a fuel injector actuation module 38 , a fuel pressure determination module 40 , and a fuel system fault determination module 42 . The engine operating condition evaluation module 36 may be in communication with the fuel injector actuation module 38 and the fuel pressure determination module 40 and may determine an engine on/off condition. An engine on condition may generally correspond to pistons within the cylinders 20 being driven by combustion events within the cylinders 20 . The engine off condition may generally correspond to the pistons within the cylinders 20 being stationary. The engine operating condition evaluation module 36 may provide a signal to the fuel injector actuation module 38 and the fuel pressure determination module 40 indicative of the engine on/off condition.
[0019] The fuel injector actuation module 38 and the fuel pressure determination module 40 may be in communication with one another. The fuel pressure determination module 40 may additionally be in communication with the fuel pressure sensor 32 and may determine an operating fuel pressure within the fuel volume (V). The fuel pressure determination module 40 may provide a signal to the fuel injector actuation module 38 indicative of the operating fuel pressure and the fuel injector actuation module 38 may provide a signal to the fuel pressure determination module 40 indicating when the fuel injectors 30 have been actuated. The fuel pressure determination module 40 may additionally be in communication with the fuel system fault determination module 42 . The fuel system fault determination module 42 may determine a system fault based on the operating fuel pressure as discussed below.
[0020] Referring now to FIG. 3 , control logic 110 is illustrated for fuel system control. Control logic 110 may begin at block 112 where the engine operating condition is evaluated by the engine operating condition evaluation module 36 . If the engine 12 is on, control may return to block 112 . If the engine 12 is off, control logic 110 may proceed to block 114 and wait a predetermined time (t). Control logic 110 may then proceed to block 116 where fuel pressure determination module 40 determines the fuel pressure (P) within the fuel volume (V). Control logic 110 may then proceed to block 118 where the fuel pressure (P) is evaluated by fuel injector actuation module 38 . If the fuel pressure (P) is below a first predetermined pressure limit (LIMIT 1 ), control logic 110 may terminate. Otherwise, control logic 110 may proceed to block 120 where at least one of the fuel injectors 30 is actuated by the fuel injector actuation module 38 . The fuel injectors 30 may be actuated for 100 microseconds or more at block 120 . The control logic 110 may actuate as few as one and as many as all of the fuel injectors 30 at block 120 . Control logic 110 may then proceed to block 122 .
[0021] Fuel pressure determination module 40 may again determine the fuel pressure (P) within the fuel volume (V) at block 122 . Control logic 110 may then proceed to block 124 where the fuel pressure (P) is evaluated by fuel system fault determination module 42 . If the fuel pressure (P) is above a second predetermined pressure limit (LIMIT 2 ), control logic 110 may proceed to block 126 where a fault is indicated. The fault may generally indicate a faulty pressure sensor 32 . Control logic 110 may then terminate. If the fuel pressure (P) is below the second predetermined pressure limit (LIMIT 2 ), control logic 110 may terminate after block 124 . The first predetermined pressure limit (LIMIT 1 ) and the second predetermined pressure limit (LIMIT 2 ) may be equal to one another and may be less than or equal to 5 MPa.
[0022] After the engine 12 is shut down, the pressure within the fuel volume (V) may gradually be reduced via leakage through the fuel injectors 30 . The predetermined time (t) may correspond to an expected pressure drop (ΔP e ) producing the first and second predetermined pressure limits (LIMIT 1 , LIMIT 2 ) in the fuel volume (V) after engine shutdown. The predetermined time (t) may be empirically derived and may vary based on a given engine application. However, by way of non-limiting example, the predetermined time may be greater than 15 seconds, and more specifically greater than 30 seconds. The expected pressure drop (ΔP e ) may generally correspond to a pressure drop from an engine idle condition immediately prior to shutdown. For example, the fuel volume (V) may be operating at approximately 30 MPa at idle and the expected pressure after time (t) may be less than 5 MPa. Therefore, in the present example, the expected pressure drop (ΔP e ) may be approximately equal to 25 MPa.
[0023] Different fuel types may have difficulty leaking through the fuel injectors 30 after engine shutdown, maintaining a high pressure within the fuel volume (V). For example, biodiesel and contaminated fuel may have difficulty leaking through the fuel injectors 30 . Therefore, fuel pressure within the fuel volume (V) may remain high after engine shutdown. Actuation of the fuel injectors 30 after engine shutdown may generally alleviate any high pressure condition maintained due to the issues described about with respect to fuel leak rates. However, high pressure readings may still occur even after the actuation of the fuel injectors 30 due to a faulty pressure sensor 32 . | A fuel system control method may include determining when an engine transitions from an engine on condition to an engine off condition. The method further includes determining a first fuel pressure in a fuel system of the engine a predetermined time after the determined engine off condition. A fuel injector of the fuel system may be actuated during the engine off condition when the first determined fuel pressure is above a first predetermined pressure limit to bleed fuel from the fuel system and reduce pressure within the fuel system. | Briefly outline the background technology and the problem the invention aims to solve. | [
"FIELD [0001] The present disclosure relates to fuel system control strategies.",
"BACKGROUND [0002] This section provides background information related to the present disclosure which is not necessarily prior art.",
"[0003] Engines may include fuel pressure sensors to determine and control operating pressures therein.",
"After engine shutdown, high pressure fuel systems may bleed fuel from the system through clearances in the fuel injectors.",
"However, some fuel types may have difficulty leaking through the fuel injectors after engine shutdown.",
"This may hinder service of the fuel system due to high pressure being maintained after engine shutdown.",
"Additionally, this may result in longer than expected leak times and may set a false error indicating a pressure sensor failure.",
"SUMMARY [0004] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.",
"[0005] A fuel system control method may include determining when an engine transitions from an engine on condition to an engine off condition.",
"The method further includes determining a first fuel pressure in a fuel system of the engine a predetermined time after the determined engine off condition.",
"A fuel injector of the fuel system may be actuated during the engine off condition when the first determined fuel pressure is above a first predetermined pressure limit to bleed fuel from the fuel system and reduce pressure within the fuel system.",
"[0006] The method may additionally include determining a second fuel pressure in the fuel system after the actuating and indicating a system fault when the second fuel pressure is above a second predetermined pressure limit.",
"[0007] A control module may include an engine operating condition evaluation module, a fuel pressure determination module, and a fuel injector actuation module.",
"The engine operating condition evaluation module may determine when an engine transitions from an on condition to an off condition.",
"The fuel pressure determination module may be in communication with the engine operating condition evaluation module and may determine a first fuel pressure in a fuel system of the engine a predetermined time after the determined engine off condition.",
"The fuel injector actuation module may be in communication with the fuel pressure determination module and may actuate a fuel injector of the fuel system during the engine off condition when the first determined fuel pressure is above a first predetermined pressure limit to bleed fuel from the fuel system and reduce pressure within the fuel system.",
"[0008] Further areas of applicability will become apparent from the description provided herein.",
"The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.",
"DRAWINGS [0009] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.",
"[0010] FIG. 1 is a schematic illustration of an engine assembly according to the present disclosure;",
"[0011] FIG. 2 is a schematic illustration of a control module of the engine assembly of FIG. 1 ;",
"and [0012] FIG. 3 is an illustration of control logic for operation of the engine assembly of FIG. 1 .",
"[0013] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.",
"DETAILED DESCRIPTION [0014] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.",
"For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements.",
"As used herein, the term “module”",
"refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, or other suitable components that provide the described functionality.",
"[0015] Referring to FIG. 1 , an exemplary engine assembly 10 is schematically illustrated.",
"The engine assembly 10 may include an engine 12 in communication with a fuel system 14 and a control module 16 .",
"The engine 12 may include an engine block 18 defining a plurality of cylinders 20 in communication with the fuel system 14 .",
"[0016] The fuel system 14 may include a fuel tank 22 , a fuel pump 24 , a fuel line 26 , a fuel rail 28 , fuel injectors 30 , and a pressure sensor 32 .",
"The fuel injectors 30 may be in direct communication with the cylinders 20 , forming a direct injection arrangement.",
"More specifically, the engine 12 may be a diesel engine and the fuel tank 22 may store a supply of diesel fuel.",
"The fuel injectors 30 may be solenoid actuated, each including a solenoid 34 in communication with the control module 16 and selectively displacing a valve member (not shown) in the fuel injector 30 to provide a pressurized fuel flow to the cylinders 20 .",
"However, while described with respect to a diesel engine, it is understood that the present disclosure is not limited to diesel applications.",
"[0017] During operation, the fuel pump 24 may provide a pressurized fuel flow from the fuel tank 22 to the fuel rail 28 via the fuel line 26 .",
"The fuel line 26 and the fuel rail 28 may define a fuel volume (V) between the fuel pump 24 and the fuel injectors 30 .",
"During engine operation, the fuel volume (V) may be maintained at a pressure greater than 30 megapascal (MPa).",
"For example, the pressure within the fuel volume (V) during engine idle conditions may be greater than 30 MPa.",
"The pressure sensor 32 may be in communication with the fuel volume (V) to monitor the fuel pressure.",
"In the present example, the pressure sensor 32 is in communication with the fuel rail 28 and monitors the fuel pressure therein.",
"[0018] Referring now to FIG. 2 , the control module 16 may include an engine operating condition evaluation module 36 , a fuel injector actuation module 38 , a fuel pressure determination module 40 , and a fuel system fault determination module 42 .",
"The engine operating condition evaluation module 36 may be in communication with the fuel injector actuation module 38 and the fuel pressure determination module 40 and may determine an engine on/off condition.",
"An engine on condition may generally correspond to pistons within the cylinders 20 being driven by combustion events within the cylinders 20 .",
"The engine off condition may generally correspond to the pistons within the cylinders 20 being stationary.",
"The engine operating condition evaluation module 36 may provide a signal to the fuel injector actuation module 38 and the fuel pressure determination module 40 indicative of the engine on/off condition.",
"[0019] The fuel injector actuation module 38 and the fuel pressure determination module 40 may be in communication with one another.",
"The fuel pressure determination module 40 may additionally be in communication with the fuel pressure sensor 32 and may determine an operating fuel pressure within the fuel volume (V).",
"The fuel pressure determination module 40 may provide a signal to the fuel injector actuation module 38 indicative of the operating fuel pressure and the fuel injector actuation module 38 may provide a signal to the fuel pressure determination module 40 indicating when the fuel injectors 30 have been actuated.",
"The fuel pressure determination module 40 may additionally be in communication with the fuel system fault determination module 42 .",
"The fuel system fault determination module 42 may determine a system fault based on the operating fuel pressure as discussed below.",
"[0020] Referring now to FIG. 3 , control logic 110 is illustrated for fuel system control.",
"Control logic 110 may begin at block 112 where the engine operating condition is evaluated by the engine operating condition evaluation module 36 .",
"If the engine 12 is on, control may return to block 112 .",
"If the engine 12 is off, control logic 110 may proceed to block 114 and wait a predetermined time (t).",
"Control logic 110 may then proceed to block 116 where fuel pressure determination module 40 determines the fuel pressure (P) within the fuel volume (V).",
"Control logic 110 may then proceed to block 118 where the fuel pressure (P) is evaluated by fuel injector actuation module 38 .",
"If the fuel pressure (P) is below a first predetermined pressure limit (LIMIT 1 ), control logic 110 may terminate.",
"Otherwise, control logic 110 may proceed to block 120 where at least one of the fuel injectors 30 is actuated by the fuel injector actuation module 38 .",
"The fuel injectors 30 may be actuated for 100 microseconds or more at block 120 .",
"The control logic 110 may actuate as few as one and as many as all of the fuel injectors 30 at block 120 .",
"Control logic 110 may then proceed to block 122 .",
"[0021] Fuel pressure determination module 40 may again determine the fuel pressure (P) within the fuel volume (V) at block 122 .",
"Control logic 110 may then proceed to block 124 where the fuel pressure (P) is evaluated by fuel system fault determination module 42 .",
"If the fuel pressure (P) is above a second predetermined pressure limit (LIMIT 2 ), control logic 110 may proceed to block 126 where a fault is indicated.",
"The fault may generally indicate a faulty pressure sensor 32 .",
"Control logic 110 may then terminate.",
"If the fuel pressure (P) is below the second predetermined pressure limit (LIMIT 2 ), control logic 110 may terminate after block 124 .",
"The first predetermined pressure limit (LIMIT 1 ) and the second predetermined pressure limit (LIMIT 2 ) may be equal to one another and may be less than or equal to 5 MPa.",
"[0022] After the engine 12 is shut down, the pressure within the fuel volume (V) may gradually be reduced via leakage through the fuel injectors 30 .",
"The predetermined time (t) may correspond to an expected pressure drop (ΔP e ) producing the first and second predetermined pressure limits (LIMIT 1 , LIMIT 2 ) in the fuel volume (V) after engine shutdown.",
"The predetermined time (t) may be empirically derived and may vary based on a given engine application.",
"However, by way of non-limiting example, the predetermined time may be greater than 15 seconds, and more specifically greater than 30 seconds.",
"The expected pressure drop (ΔP e ) may generally correspond to a pressure drop from an engine idle condition immediately prior to shutdown.",
"For example, the fuel volume (V) may be operating at approximately 30 MPa at idle and the expected pressure after time (t) may be less than 5 MPa.",
"Therefore, in the present example, the expected pressure drop (ΔP e ) may be approximately equal to 25 MPa.",
"[0023] Different fuel types may have difficulty leaking through the fuel injectors 30 after engine shutdown, maintaining a high pressure within the fuel volume (V).",
"For example, biodiesel and contaminated fuel may have difficulty leaking through the fuel injectors 30 .",
"Therefore, fuel pressure within the fuel volume (V) may remain high after engine shutdown.",
"Actuation of the fuel injectors 30 after engine shutdown may generally alleviate any high pressure condition maintained due to the issues described about with respect to fuel leak rates.",
"However, high pressure readings may still occur even after the actuation of the fuel injectors 30 due to a faulty pressure sensor 32 ."
] |
This application is a continuation-in-part of U.S. patent application Ser. No. 09/665,636 filed Sep. 19, 2000 now abandoned.
FIELD OF THE INVENTION
The present invention relates to hypodermic needle holders, suture needle disposal and disposal structures, and more specifically to a hypodermic needle holder and disposal structure that minimizes the risk of inadvertent needle sticks that may result from coupling or uncoupling a hypodermic needle from a hypodermic syringe or recapping a hypodermic needle, or may result from improper storage of a hypodermic needle while the needle is temporarily not in use.
BACKGROUND OF THE INVENTION
Use and handling of hypodermic needles is a frequent occurrence in the field of medicine. Hypodermic needle systems typically consist of a hypodermic syringe that is quickly and easily removably attachable to a variety of hypodermic needle types and sizes by frictional engagement or by screw-on engagement, the latter of which is usually achieved using a LUERLOCK system. Handling and use of hypodermic needles inherently includes a certain amount of risk of accidental needle stick either to the person who may be administering an injection or to others in the immediate vicinity if a used hypodermic needle is improperly stored or carelessly placed prior to disposal.
Recapping a hypodermic needle after an injection is a likely cause of a large percentage of the composite risk factor for needle sticks in health care settings; most institutions discourage recapping of hypodermic needles under any circumstances. In some states and counties, safety laws prohibit recapping and other unsafe disposal practices. Unfortunately, this may also mean that the person responsible for disposing of a used hypodermic needle and syringe may have to travel more than a short distance to reach a sharps disposal container, thereby exposing more people than necessary to the potential hazard of incurring a needle stick and increasing their own risk for injury en route.
In some procedures, and for a given patient, there arises the need to re-use a needle during the procedure. For dentists who apply numbing medication in the oral cavity, repeated applications may be required with corresponding re-use of the needle. In other re-anesthetizing uses, such as during suturing, a needle may be re-used. For example, where the tissue requires further, later in time handling of the syringe and needle to either continue anesthization or to move on to another area on the patient's body. In these and many other re-use scenarios, there is simply no proper procedure for interim protection of personnel, isolation of the used and to be used again needle. In some hospitals it is required that a drape cover the sterile field when significant time elapses between a procedure and the next procedure, or where when significant time elapses between a series of procedures. The use of a drape can pick up contamination and spread it with subsequent manipulation of the drape. The drape may catch on the needle or other objects in the sterile field and produce a stick through the drape or even catch the needle and cause it to drop to the floor when the drape is removed. Although the use of the drape to block dust and airborne contaminants, the increased risk of sticks, cuts and upset spills of the materials in the field increase several fold when the drape covers the objects in the field, and there is furter increase of accident each time the drape is handled after its initial deployment.
Even systems which are tauted to be “needle-less” continue to create a danger of needle stick. One recent system includes a seventeen gauge tube with a generally blunt (transverse even tubular end) end which is supposed to be protected by a sleeve. If anything, this system is just as apt to create accidental stick contamination as the needle end is hidden until it makes contact with the skin, and the temporary hiding of the needle in the sleeve causes unwarranted reliance on the sleeve with increased carelessness.
Further, in health care settings, certain intravenous medications are required to be given in incremented doses and are repeated until a desired effect is achieved. When this is the case, it is not uncommon to repeatedly fill the same hypodermic syringe with medication and to perform repeated intravenous injections into a port that leads directly to a vein or leads into an intravenous fluid line that terminates in a vein. This is usually the case, for example, with patients who have problems of an emergent nature, such as cardiac or respiratory arrest, or problems of an urgent nature such as heart failure or respiratory difficulty, or even for patients undergoing surgery. Because large volumes of fluid may be drawn up into a hypodermic syringe in anticipation of needing them, they are often drawn up using a large gauge hypodermic needle, such as an 18 or even a 16 gauge hypodermic needle for speed and convenience, and this may include the above “needle-less” system. Injecting an intravenous port with such a large gauge hypodermic needle even once could damage the membrane of the port, causing leakage at the port, and thus rendering the entire intravenous tubing useless such that it would have to be replaced. For this reason, administration of intravenous medications typically takes place using a smaller gauge hypodermic needle, usually less than a 20 gauge. This may require that the large gauge needle and the small gauge needle be intermittently exchanged for one another, and certainly requires that whichever needle is not in use be kept from contamination. In dire circumstances, where the patient's condition may be serious and where the environment is likely to be somewhat chaotic as a result, the chances of improper placement of a used hypodermic needle increases significantly. Subsequently, the risk of hypodermic needle contamination increases, as does the risk for inadvertent needle stick for personnel who are caring for the patient, and even for family members or others who may be present.
In caring for a patient who receives frequent injections of any kind at the bedside, health care personnel may have their attention diverted from the task at hand by some distraction, and may subsequently place a used hypodermic needle on a bedside table or even on the bed beside the patient in order to address the distraction. Not only could this practice cause unintentional injury to the patient, but health care personnel and others who may have occasion to enter a patient's room after the fact are also at risk of being stuck or otherwise injured by the stray hypodermic needle.
Yet another potentially harmful procedure is that of drawing up medications from a vial that requires puncture of a membrane in order to access the medication within the vial. Although the hypodermic needle is not biologically contaminated, this practice still presents the potential for injury to the health care worker or others, since it requires recapping the hypodermic needle until the medication is to be administered. Similarly, medications contained in scored glass vials that require breakage of the vial and drawing up of the medication through a hypodermic needle is another practice that increases risk of needle stick, primarily because of the need for recapping the hypodermic needle prior to giving the injection.
A carelessly placed hypodermic needle that causes injury may result in temporary incapacitation of the health care team member who sustains the injury. Prompt treatment of the injury is encouraged by most institutions, and incident reports are mandatory, thereby potentially compromising patient well-being by decreasing the number of staff available for immediate patient care.
Yet another potentially injurious situation is that involving hypodermic needle disposal. Disposing of an uncapped hypodermic needle, even into a designated sharps container, can be a dangerous act in itself. Because of the design of most sharps containers, if the container is nearly full, it can prove to be difficult if not impossible to safely insert an exposed hypodermic needle into the box without injury either from the hypodermic needle being inserted or from other needles that may have become lodged in the opening of the box.
While hypodermic needles and syringes are likely the cause of most needle stick injuries, surgical needles and other small sharps containers commonly used in a health care setting are also potential hazards if not disposed of properly. Because suture needles are quite small, simple suturing at a patient's bedside may result in misplacement of the small suture needle and attached thread should it not be immediately disposed of or placed in a safe location prior to its disposal. A stray needle in the patient's bed or on the floor could result in patient injury or injury to health care workers, patient family, or others who may come in contact with the patient or who may have occasion to be in the patient's room. Lack of an appropriate disposal container in an operating room could also lead to misplacement of suture needles during a patient's surgery; this could be particularly problematic, and could place the patient in unnecessary danger by delaying the completion of the surgery until all suture needles are located.
Other persons at risk for injury from needle stick include family members or unskilled lay persons who may help to care for patients in a home setting and who may regularly assist, for example, with subcutaneous administration of medications such as insulin. Other persons at risk include paramedics and emergency health workers who are always on the move, continually working in harried, difficult conditions and have no prepared surgical field to use as a base of operations. With paramedics, for example, time is of the essence. If too much time is required in either disposing of or temporarily storing a needle, the parametic may toss it on the ground where it may contaminate others or toss it in the medical kit. Without a proper, inviting and very available place to both store needles during extended procedures and to at least safely and temporarily dispose of needles on the move, needle sticks and the like will remain a major problem to emergency health professionals.
Yet another situation where accidental needle sticks or other injury can occur is after an intravenous line is initiated on a patient. Because the intravenous catheters used are catheter-over-the needle systems, once the catheter is in place, the needle is extracted and disposed of. Whether the intravenous line is started in an emergency situation that may be chaotic, or whether started in the most optimal of situations, the needle may be improperly placed on whatever surface is nearest at hand so that the catheter may be secured and fluids or medication may be administered. Should the needle be forgotten once the procedure is complete, it will pose a risk for those in the immediate vicinity. Some new catheter systems include safety devices, but use of such devices still involves the needle being left out with continued danger of needle sticks at the point.
Although most, if not all, health care institutions have designated procedures for the proper use and disposal of needles, and although most institutions additionally require health care workers to attend continuing education classes for learning safe handling and disposal of sharps and other biologically contaminated equipment, accidental needle sticks continue to occur and are an ongoing problem. The risk of accidental needle stick is cause for serious concern, both to health care workers and to others who may be exposed to the use of hypodermic syringes and needles of any kind, due to the existence and transmissibility of life threatening blood-borne diseases such as hepatitis, and Acquired Immune Deficiency Syndrome (AIDS).
What is therefore needed is a device and method that is easy and convenient to use and that will minimize the risk associated with handling and disposal of hypodermic needles and hypodermic syringes. The proposed device should be useable by trained health care personnel, as well as by unskilled lay persons such as patients, family members, and other care givers. The proposed device should be able to accommodate a variety of sharps or similarly small biologically contaminated items that would be ill disposed of in an ordinary trash can.
Numerous attempts have been made in the prior art to design a safe disposal container for hypodermic syringes and needles. However, such devices do not allow for both the removal and attachment of hypodermic syringes and needles in a safe manner. Such devices also do not teach their sterilization to enable them to be used in any capacity other than their capacity for disposal. All of the prior devices for holding and facilitating safe disposal of the needles will destroy the sterility of the sterile field. Any health care worker walking about with an open container full of contaminated needles should not be allowed anywhere near a sterile field. Many of the devices are not only too contaminated, they are too large for the sterile field. Most of the prior devices which will accommodate large numbers of syringe needles, by being contaminated, require the health care workers to carry the needles to it, again exacerbating the handling problem and increasing danger to others from open carriage of the contaminated material. In prior devices, no attempt is made to either start with a sterile space nor to isolate stored needles from other needles which have been contaminated by other patients.
For example, U.S. Pat. No. 5,046,612 issued to Mostarda et al. and U.S. Pat. No. 4,917,243 issued to Abrams both provide hand held receptacles that extract hypodermic needles from hypodermic syringes. As such the used hypodermic needles are longitudinally placed inside the receptacle and removed from the hypodermic syringe to thereby reduce the risk of injury from the hypodermic needle tip. Both inventions provide different means for inserting the hypodermic needle into the receptacle longitudinally such that the risk of exposure to the sharpened hypodermic needle tip is reduced. However, there are no methods for reusing the hypodermic needle as is necessary when re-filling a hypodermic syringe with fluid or medication or re anesthetizing a patient, or re-injection of a joint.
In U.S. Pat. No. 5,057,656 issued to Galber, a disposal container for hypodermic needles is provided. The container includes a top with suitability shaped openings for the removal of hypodermic needles from hypodermic syringes. Used hypodermic needles are disposed inside the container to protect the health care worker. Also, the needles inserted into the foam filled container can't be reversed and used again as foam fills the needle opening.
Furthermore, in U.S. Pat. No. 4,375,849 issued to Nahifl and U.S. Pat. No. 4,351,434 issued to Elisha, hypodermic needles are disposed in a cylindrical container through an opening in the container top. However, such containers pose a risk of injury to the health care worker because the container is usually held with a hand that can be punctured by the exposed hypodermic needle tip as it is inserted into the container. As such, these containers do not provide a safe method of disposal. Similarly, U.S. Pat. No. 4,995,871 issued to Sasaki et al. And U.S. Pat. No. 4,984,686 issued to Shillington provide enclosure lids that extract the hypodermic needle from the hypodermic syringe and then dispose of the hypodermic needle in an attached container. However, both devices are complex and not easily manufactured and do not provide for the safe storage of exposed hypodermic needle tips.
Additionally, U.S. Pat. No. 4,892,191 issued to Nakamura, discloses a container for the removal and disposal of press or slip type hypodermic needles attached to a hypodermic syringe while U.S. Pat. No. 4,802,579 issued to Hall et al. discloses a container which removes and disposes of hypodermic needles that use screw threads to attach the hypodermic syringe. In both devices, the hypodermic needle is inserted into the disposal container through an opening and engaged thereby. The opening is then used to remove the hypodermic needle from the hypodermic syringe and the exposed hypodermic needle is dropped down into the container. However, neither of these devices provide means for storing the exposed hypodermic needles while being attached or removed from the hypodermic syringe before being disposed.
Furthermore, U.S. Pat. No. 4,191,264 issued to Shinall discloses a removal and disposal device for hypodermic needles. The device comprises individual containers that remove and store the used hypodermic needle in a tacky substance. As such, the device is complicated and expensive to manufacture and does not allow needle re-use. Similarly, U.S. Pat. No. 4,452,358 discloses a box-like device wherein the hypodermic needle is destroyed while being removed from the hypodermic syringe and the container includes multiple compartments and openings for the disposal of other medical instruments such as scalpel blades.
As can be seen from the related prior art, numerous devices have been designed for the disposal of hypodermic syringes and needles. However, none of the prior art devices provide an apparatus that can safely remove, attach and store the hypodermic needle and then properly dispose of the hypodermic needle after use.
What is therefore needed is an inexpensive device that protects the health care worker from inadvertent needle sticks while handling hypodermic needles and syringes. The needed device and method should be simple to use and therefore optimal for use by both trained professional health care workers as well as unskilled lay persons who may have need of using hypodermic syringes and needles in a home care setting. Additionally, there exists a need for provision of both storage of hypodermic needles, with or without a hypodermic syringe attached, and for disposal of hypodermic needles quickly and safely after their use and subsequent detachment from hypodermic syringes. Furthermore, there is a need for containment and disposal of other sharp objects such as suture needles, or other small items that may be biologically contaminated and that would be more appropriately disposed of in a biological waste container rather than in a trash can.
SUMMARY OF THE INVENTION
The needle holder of the present invention has a variety of features that make it an optimal device for safe storage and disposal of hypodermic needles. Further, the needle holder of the present invention is also able to accommodate surgical needles or other small sharps or biologically contaminated articles, and may be easily and conveniently employed in a variety of settings. Alternative embodiments of the present invention will accommodate double-ended hypodermic needles, and larger versions of hypodermic needles such as thoracic, cardiac, or spinal needles.
In the preferred embodiment of the present invention, there is provided a hypodermic needle holder which works with a hypodermic needle having a needle hub adjacent a needle shaft and terminating at a needle tip. The hypodermic needle holder comprises a body portion and a lid portion, the body portion of which defines a compartment having a plurality of needle retainers disposed in a side-by-side relation therein. The needle retainers are sized and configured to frictionally engage the needle hub of a hypodermic needle in a manner wherein the hypodermic needle is fixedly contained within the needle retainer. The needle retainers are frustoconical or conically or of tapering shape and also specially internally shaped for frictional retention of the hypodermic needles. The compartment has a generally rectangular configuration and is optimally formed from a rigid and durable plastic material. The lid portion of the hypodermic needle holder is moveable between an open position where the needle retainers are accessible and a closed position whereat the needle retainers are shielded within the hypodermic needle holder.
The hypodermic needle holder of the present invention also includes a receptacle into which smaller sized needles such as surgical needles may be placed after use. Furthermore, this receptacle may be used for small items such as cotton balls, gauze pads, or discontinued intravenous catheters that may be biologically contaminated and that would be best disposed of in a bio-hazardous waste container. The material from which the needle holder may be constructed may be clear in order to facilitate a visual count of suture needles as well as a count of engaged and stored hypodermic needles.
In an alternative embodiment of the present invention, the size of the overall hypodermic needle holder and of the needle retainers themselves are elongated in order to contain longer hypodermic needles such as cardiac, thoracic, or spinal needles.
In yet another alternative embodiment of the present invention, a container is provided with a slightly larger opening in order to accommodate a double ended hypodermic needle such as those used in many dental practices, as well as those used in the medical profession primarily by phlebotomists and in conjunction with devices such as VACUTAINERS.
Further there is provided a method for transferring attachment of a hypodermic needle to or from a hypodermic syringe through the use of a hypodermic needle holder which includes an opening with at least one engaging needle retainer disposed therein. The method includes frictionally engaging the hypodermic needle to the needle retainer both by insertion friction and turning friction. The hypodermic syringe is advanced into the opening of a hypodermic needle holder and subsequently into a needle retainer space and retainer structure for initial axial frictional engagement to cause the hypodermic needle to be frictionally engaged with the retainer structure. The hypodermic syringe can be disengaged from the hypodermic needle by a turning motion against the friction and locking holding power of the needle retainer, to disengage the needle from its LUER fitting. The hypodermic syringe can be re-engaged onto the hypodermic needle by approach of the syringe, and physical engagement of the LUER fitting by a turning motion against the friction and locking holding power of the needle retainer, to re-engage the LUER fitting. Once re-engaged, a simple axial pulling of the syringe and LUER attached needle will disengage the hypodermic needle from the needle retainer. If needed, the hypodermic needle and syringe combination can be disengaged from the needle retainer and removed from the opening of the hypodermic needle holder for further use. By providing a relatively larger structure than a simple cap, movement of the hypodermic needle into and from its storage area is accomplished while the fingers and hand not holding the hypodermic syringe can support the hypodermic needle holder significantly far from the area of entrance of the needle into the hypodermic needle holder. Furthermore, the hypodermic needle holder includes an openable and closable lid portion for selectively accessing the needle retainer wherein the lid portion must be opened prior to advancing the hypodermic syringe into the opening of the hypodermic needle holder.
The present invention further includes a method of removing a hypodermic needle from a hypodermic syringe that includes a hypodermic needle holder having an opening with at least one needle retainer disposed therein. The method comprises advancing a hypodermic syringe with a hypodermic needle coupled thereto into the hypodermic needle holder and subsequently into the needle retainer. Next, the hypodermic needle is frictionally engaged to the needle retainer. The hypodermic syringe is then uncoupled from the hypodermic needle, leaving the hypodermic needle engaged within the needle retainer. The hypodermic syringe and needle may be coupled via a frictional engagement wherein uncoupling the hypodermic syringe from the hypodermic needle comprises pulling the hypodermic syringe away from the hypodermic needle. Alternatively, the hypodermic syringe and needle may be coupled via a LUER fitting such that uncoupling the hypodermic syringe from the hypodermic needle comprises rotation of the hypodermic syringe to disengage the hypodermic needle. Furthermore, the hypodermic needle holder includes a lid portion such that the lid portion must be opened prior to the advancement of the hypodermic syringe into the hypodermic needle holder.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, its configuration, construction, and operation will be best further described in the following detailed description, taken in conjunction with the accompanying drawings in which:
FIG. 1 is a view of the hypodermic needle holder of the present invention, and illustrates a body portion that defines a compartment having a receptacle at one side and a plurality of needle retainers adjacent the end receptacle, and a lid portion in an open position and with a cantilevered latch connected to the body portion and;
FIG. 2 is a perspective expanded view of a hypodermic needle and illustrates a hub adjacent a needle shaft with a beveled edge that terminates at a needle tip.
FIG. 3 is a view of more of the needle support structure of the hypodermic needle holder of FIG. 1 from an elevated perspective and illustrates the overall shape and position of the receptacle and the plurality of needle retainers, and the attachment of the lid portion in an open position with cantilevered latch;
FIG. 4 is a view of the bottom of the hypodermic needle holder of FIGS. 1 and 3 and illustrates the body portion, the extent of the structural support as an “H” overall shape, the position of the receptacle and needle retainers, and the lid portion in an open position;
FIG. 5 is a side view of the hypodermic needle holder of FIGS. 1, 3 , and 4 that best illustrates the overall shape and side-by-side orientation of the receptacle and plurality of needle retainers, and clearly illustrates the cantilevered latch extending from the lid;
FIG. 6 is a view of the top of the hypodermic needle holder of FIGS. 1, 3 , 4 , and 5 and illustrates the body portion, the position of the receptacle and needle retainers, and the lid portion in an open position with single body hinge and cantilevered latch;
FIG. 7 is an expanded view along line 7 of FIG. 6 that illustrates in more detail the configuration of each of the plurality of needle retainers;
FIG. 8 is a cross-sectional view along line 8 — 8 of FIG. 6 and more clearly illustrates the body of the hypodermic needle holder and the position of the receptacle and plurality of needle retainers therein;
FIG. 9 is a cross-sectional view along line 9 — 9 of FIG. 5 and more clearly illustrates one of the plurality of needle retainers and its position relative to the body portion, lid portion, and cantilevered latch thereon the lid portion;
FIG. 10 is an expanded view along line 10 of FIG. 9 that illustrates in detail a catch on the cantilevered latch on the lid portion of the hypodermic needle holder;
FIG. 11 is a cross-sectional view along line 11 — 11 of FIG. 5 that more closely illustrates the overall shape of the receptacle and its position relative to the lid portion of the hypodermic needle holder;
FIG. 12 is an expanded view along line 12 of FIG. 11 that illustrates a bifurcation in the lid portion to allow for movement of the lid portion;
FIG. 13 is a top view of a second embodiment of the hypodermic needle holder configured to accommodate a pair of double-ended needles such as dental needles or needles used for phlebotomy;
FIG. 14 is a side view of the second embodiment of the needle holder with an elongated needle accommodation portion utilizable for longer needles, such as cardiac needles, and further illustrating a double-ended needle for illustration purposes;
FIG. 15 is a view taken along section 15 — 15 of FIG. 7 and illustrating a frontal view of one of side of the four square openings from the top of one of its four flat inner walls and proceeding downwardly into the needle accommodation chamber and particularly illustrating a slanted bib surface which transitions into an inwardly curved surface and which finally transitions to a generally straight angled frustoconical surface;
FIG. 16 is a side view as seen in FIG. 15 and illustrating the lateral extent of the associated surfaces seen at the same level as seen in FIG. 15;
FIG. 17 is a perspective view of a further embodiment of the hypodermic needle holder having a positive lock lid which is tamper resistant, and having outwardly and downwardly extending projections to independently stabilize the holder; and
FIG. 18 is a side view and illustrating further details of the embodiment of FIG. 17 and including a peel strip for attaching the holder to another surface.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The description and operation of the hypodermic needle holder of the invention will be best described with reference to FIG. 1 . The hypodermic needle holder 11 includes a body portion 13 having an upper wall 14 that defines an opening 15 . Note that while the overall shape of the opening 15 of the hypodermic needle holder 11 in the preferred embodiment is elongate oval, a variety of shapes is possible without compromise of functionality, such as rectangular, rectangular with curved edges, and the like. The opening 15 is enclosable by a lid portion 21 adjacent the opening 15 of the body portion 13 . The lid portion 21 has a cantilever operated latch 23 adjacent a rectangular opening 24 and attached from the lid portion 21 . Cantilever operated latch 23 terminates in a right angled extension to form a catch 25 . The body portion 13 , attached to the lid portion 21 further defines a planar portion 31 , within the space beyond the opening 15 , having a single circular opening 33 and a series of generally square openings 35 , each of the series of square openings 35 are in turn surrounded by a plurality of tapered blind bores 37 , separated by a series of four rectangularly placed planar members 39 . Each of the series of square openings 35 is arranged in a side-by-side configuration with each of the others in the series of square openings 35 , and with respect to the single circular opening 33 . This arrangement is not exhaustive of the spatial arrangements possible, but in the preferred embodiment of the hypodermic needle holder 11 it does have a low profile in one dimension to facilitate disposal in a sharps container having a narrow opening. The single circular opening 33 in the planar portion 31 leads into a frustoconical shaped receptacle 43 defined by the body portion 13 of the hypodermic needle holder 11 for containment and eventual disposal of small sharps such as surgical needles, or small biologically contaminated items such as cotton balls, gauze squares, or even discontinued intravenous catheters.
Each of the series of square openings 35 leads into a corresponding one of a plurality of needle retainers 45 defined by the body portion 13 of the hypodermic needle holder 11 . The frustoconically shaped receptacle 43 and plurality of needle retainers 45 are arranged such that their longitudinal axes are parallel with one another in order to save space. The axes of the frustoconical receptacle 43 and plurality of needle retainers 45 are arranged generally parallel with the general longitudinal extent of the holder 11 . The axes of the frustoconical receptacle 43 , and plurality of needle retainers 45 are perpendicular to the planar portion 31 .
The hypodermic needle holder 11 may be optimally constructed from a durable but slightly flexible material such as injection molded plastic, that will allow some radially outwardly displacement of each planar member 39 forming each wall of the square of the series of square openings 35 and into the area of each of the plurality of blind bores 37 . Any radially outward displacement as a result of inserting a needle (illustrated in FIG. 2) provides an inward grip, in addition to the spatial engagement of the square shape of the planar members on the square aspects of a needle. Construction of the hypodermic needle holder 11 from such a slightly flexible material will thus result in a displacement based inward biasing of the material toward the hub of the needle (illustrated in FIG. 2) for enhancing the frictional engagement and trapping of the needle within the hypodermic needle holder 11 . The body portion 13 of the hypodermic needle holder 11 also defines four tapered flanges 47 extending away from the end of the holder 11 adjacent the opening 15 , and arranged such that each of two pairs of tapered flanges 47 is disposed at opposite lateral sides of the hypodermic needle holder 11 , with one of each pair oppositely disposed from the other of each pair. The tapered flanges 47 help to stabilize the hypodermic needle holder 11 during upright placement on a planar surface such as a table, as well as provide overall structural strength and integrity.
FIG. 2 is a view of a hypodermic needle 51 having a needle hub 53 with opening 55 surrounded by a square flange member 56 to complete a LUER fitting. Between the hub 53 and a needle shaft 57 , is a series of four projecting ribs 59 which give the lower part of the hub 53 a square profile to provide a rotational lock with respect to the planar members 39 forming each wall of the square of the series of square openings 35 . Each of the projecting ribs 59 will fit at a corner of the junction of each of the planar members 39 to provide a square rotational lock, in addition to the frictional engagement from axial insertion of the hypodermic needle. Needle shaft 57 has a beveled edge 61 that terminates at a needle tip 63 .
FIG. 3 is a perspective view of the reverse side of the hypodermic needle holder 11 , with respect to the perspective view of FIG. 1 from an elevated perspective and further illustrates the lid portion 21 as having one or more bifurcations 71 adjacent the body portion 13 and extending across the full width of the lid portion 21 at its connection to the body portion 13 . The bifurcation 71 may preferably be a thinning of the material in order to direct and control the lid portion 21 to close in a mating relationship over the opening 15 . Further, the bifurcation or bifurcations 71 allow a user to manually and orderly open the lid portion 21 in order to gain access to the needle retainers 45 or frustoconical receptacle 43 , or to close the lid portion 21 in order to enclose the contents of the frustoconical receptacle 43 and the plurality of needle retainers 45 for safety or for containment of biologically contaminated items.
Ideally, the hypodermic needle holder 11 of the present invention would be constructed of a durable, yet somewhat flexible material such as plastic, to allow for movement of the lid portion 21 without breakage at the bifurcation 71 . One material of construction is polypropylene. The bifurcation 71 has sometimes been known as a living hinge, and can be formed by controlling the thickness and width of its extent.
The body portion 13 of the hypodermic needle holder 11 defines an interstitial planar web structure 73 extending between and radially perpendicular to each of the plurality of needle retainers 45 and frustoconical receptacle 43 . The interstitial planar web structure 73 as a plane within which the axes of the plurality of needle retainers 45 and frustoconical receptacle 43 reside, thus enhancing the overall structural stability and particularly the upright stability of the hypodermic needle holder 11 . FIG. 3 further illustrates that each of the plurality of needle retainers 45 comprises a square opening 35 adjacent a chamber 74 having a tapering or frustoconical first portion 75 adjacent a conical or tapering second portion 77 .
FIG. 4 is a view of the bottom of the hypodermic needle holder 11 of FIGS. 1 and 3 and illustrates the lid portion 21 in an open position with attached cantilevered latch 23 and catch 25 (both illustrated in phantom) for securing the lid portion 21 in a closed position. FIG. 4 also illustrates the body portion 13 , the frustoconical receptacle 43 and the plurality of needle retainers 45 , each in side-by-side orientation with one another. Also illustrated herein are the tapered flanges 47 defined by the body portion 13 , and the bifurcation or bifurcations 71 in the lid portion 21 of the hypodermic needle holder that allows for and directs the movement of the lid portion 13 for opening or closing the lid portion 13 . FIG. 4 also illustrates the interstitial planar web structure 73 and better details its position in the plane formed by the longitudinal axes of the frustoconical receptacle 43 and plurality of needle retainers 45 . FIG. 4 illustrates in phantom format the opening 15 defined by the body portion 13 .
FIG. 5 is a side view of the hypodermic needle holder of FIGS. 1, 3 , and 4 . FIG. 5 illustrates the frustoconical receptacle 43 in side-by-side alignment with the plurality of needle retainers 45 , and also clearly illustrates the frustoconical first portion 75 adjacent the tapering second portion 77 of each of the chambers 74 . Also illustrated in phantom in FIG. 5 is the opening 15 defined by the wall 14 of the body portion 13 of the hypodermic needle holder 11 . The lid portion 21 is illustrated in an open position out of the plane of the page, with cantilevered latch 23 shown and catch 25 illustrated in phantom. The interstitial planar web structure 73 as well as the two of the four tapered flanges 47 is also clearly seen in FIG. 5 .
FIG. 6 is a view of the top of the hypodermic needle holder 11 of FIGS. 1, 3 , 4 , and 5 and illustrates the lid portion 21 in an open position and with attached cantilevered latch 23 and catch 25 for securing the lid portion 21 in a closed position. FIG. 6 illustrates the body portion 13 , the opening 15 defined by the body portion 13 , the planar portion 31 , the single circular opening 33 adjacent the frustoconical receptacle 43 , and the series of square openings 35 , each surrounded by plurality of blind bores 37 , separated from the square openings 35 by series of four rectangularly placed planar members 39 and each of which is adjacent one of the plurality of needle retainers 45 . Two of the tapered flanges 47 defined by the body portion 13 are also be seen in FIG. 6 . Finally, FIG. 6 illustrates in phantom the bifurcation 71 in the lid portion 21 of the hypodermic needle holder 11 that allows for movement of the lid portion 13 . The birfucation 71 could have been placed on either side of the lid portion 13 , or a pair of oppositely located shallow bifurcations could have been placed on opposite sides of the lid portion 13 , and the phantom showing is for consistency only. The main idea is some structure which guides folding.
FIG. 7 is an expanded view along line 7 of FIG. 6 and further details the configuration of one of the plurality of needle retainers 45 . FIG. 7 illustrates a section of the planar portion 31 having one of the series of square openings 35 surrounded by plurality of blind bores 37 and separated by the series of four rectangularly placed planar members 39 . Immediately inside the square opening 35 , the needle retainer 45 has four flat inner walls 83 which are immediately adjacent each the series of four rectangularly placed planar members 39 . Below the four flat inner walls, a beveled surface angled surface 85 sloping downward into a curve shaped wall 87 . The lateral extent of the angled surface 85 has a curved shape which permits the curved shaped wall 87 to lie adjacent the four flat inner walls 83 at the ends of the curved shaped wall adjacent the corners formed by the four flat inner walls 83 . The curve shaped wall 87 concentrates the contact area slightly for a more friction laden engagement with the needle hub 53 . The chamber 74 has a tapering shape leading to an abbreviated end 89 . The angled surface 85 has an adjacent shape as an upwardly open parabolic shape. The beveled surface is a shape consistent with the early extent of a diminishing tapered radius, and finally terminates on the frustoconical first portion 75 of inside of the chamber 74 of the needle retainer 45 . Note that the bounds of the convexity of the curve shaped wall 87 define an inwardly curving shape. During use, hypodermic needle 51 is inserted into the square opening 35 and is advanced toward the adjacent frustoconical first portion 75 and subsequent tapering second portion 77 of the chamber 45 so that the ribs 59 begin to place the hypodermic needle 51 in a position where it is limited in turning about its axis. Continued insertion causes the needle hub 53 to contact the curve shaped walls 87 within the frustoconical first portion 75 of the chamber 74 . As the needle hub 53 advances into the square opening 35 , the needle hub 53 will pass over the four flat inner walls 83 , angled surface 85 , and the curve shaped wall 87 . Once frictional engagement occurs, the four flat inner walls 83 may be slightly outwardly displaced to provide more frictional grasping of the needle hub 53 , especially at the middle, innermost aspect of the curve shaped walls 87 below the angled surface 85 . While the hypodermic needle 51 is in place with respect to the holder 11 , a syringe to which it is attached can be twisted to de-couple the LUER fitting to free the syringe, or the syringe can be brought again to the LUER fitting and twisted to re-couple the syringe to the hypodermic needle 51 . Withdrawal of the hypodermic needle 51 from the hypodermic needle holder 11 can then accomplished by a frictional extraction of the hypodermic needle 51 from the needle holder 11 .
FIG. 8 is a cross-sectional view of the hypodermic needle holder 11 taken along line 8 — 8 of FIG. 6 that illustrates the body portion 13 , the opening 15 defined by the body portion 13 , the cantilevered latch 23 with catch 25 , the frustoconical receptacle 43 , and the plurality of needle retainers 45 . The series of interstitial planar web structure 73 are illustrated as shaded in this figure.
FIG. 9 is a cross-sectional view taken along line 9 — 9 of FIG. 5 that more closely illustrates one of the plurality of needle retainers 45 of the hypodermic needle holder 11 . Visible is the body portion 13 , two of the tapered flanges 47 , the frustoconical receptacle 43 , the lid portion 21 , the cantilevered latch 23 with catch 25 , the bifurcation 71 in the lid portion 21 , the opening 15 defined by the body portion 13 , and the square opening 35 , frustoconical first portion, and conical second portion of the chamber 74 . A flat underside surface 91 lies adjacent and just adjacent wall 14 . Flat underside surface 91 forms a right angle with respect to the outside of wall 14 .
FIG. 10 is an expanded view along line 10 — 10 of FIG. 9 that illustrates in close detail the catch 25 of the cantilevered latch 23 of the hypodermic needle holder 11 extending at a right angle to one side and having a flat portion 93 which will contact and complementarily fit the flat underside surface 91 to enable the lid portion 21 to be locked over the opening 15 to form an enclosure from which any hypodermic needles 51 cannot escape. Typically, the lid portion 21 will be closed and locked at one time, usually just before disposal.
FIG. 11 is a cross-sectional view taken along line 11 — 11 of FIG. 5 that more closely illustrates the frustoconical receptacle 43 and single circular opening 33 of the hypodermic needle holder 11 . In FIG. 11, the body portion 13 , opening 15 defined thereby, lid portion 21 , and bifurcation 71 therein may easily be seen.
FIG. 12 is an expanded view along line 12 — 12 of FIG. 11 that more closely details the bifurcation 71 of the lid portion 21 . As has been observed, the bifurcation in this case is a thinning of the material and such thinning can occur on either or both sides of the lid portion. Multiple thinned areas can be used in order to control the bending of the material to form a hinge.
FIG. 13 is a top view of a second embodiment of the hypodermic needle holder as a holder 101 configured to accommodate a pair of double-ended needles such as dental needles or needles used in conjunction with VACUTAINERS for phlebotomy. In this embodiment of the hypodermic needle holder 101 , the diameters of the series of square openings 35 of the needle retainers 45 are sized larger to accommodate a larger needle hub (illustrated in FIG. 14 ). This embodiment of the hypodermic needle holder 11 may be utilized anywhere, but may be best suited for health care facilities such as dentist's offices, laboratories, mobile blood banks, and other locations where use of a double-ended hypodermic needle is common.
A further embodiment of the hypodermic needle holder is seen as holder 111 and is seen in FIG. 14 . The overall size of the hypodermic needle holder 111 for cardiac and other elongate needles is itself longer. Cantilevered latch 23 and catch 25 , the body portion 13 , the opening 15 defined thereby, and two of the tapered flanges 47 may also be seen in this figure. Finally, the lid portion 21 is illustrated in phantom in FIG. 14 .
FIG. 14 further illustrates, as an example, a double-ended hypodermic needle 113 . Double ended hypodermic needle 91 has a first needle shaft 115 terminating in a first needle tip 117 at one end and adjacent a needle hub 119 at an opposite end. The needle hub is adjacent one end of a second needle shaft 121 that is typically longer in length than the first needle shaft 115 and that terminates in a second needle tip 123 at an opposite end. FIG. 14 best illustrates the heightened size of the second embodiment of the hypodermic needle holder 11 to provide for accommodation of a double-ended needle 91 such as the one illustrated herein. In FIG. 14, the proper position of double-ended needle 113 for insertion into the hypodermic needle holder 111 is shown. Note that the hypodermic needle holder 11 may be also be manufactured sized to fit any length of hypodermic needle such as thoracic, cardiac, or spinal needles. The double-ended needle 113 is shown attached to a syringe 131 and is especially preferable to use the syringe 131 for insertion of doubled-ended needles for safety.
The hypodermic needle holder 11 has an unusual shape within its series of square openings 35 . The shape is intended to simultaneously (1) provde easy entry with minimum restriction, (2) provide a square engagement, and upon further insertion (3) provide a frictional hold by concentrating force on a relatively limited amount of common structure/material in order to obtain a frictional hold on the hypodermic needle 51 .
FIG. 15 is a view taken along section 15 — 15 of FIG. 7 and illustrating a frontal view of one of side of the four square openings 35 from the top of one of the four rectangularly placed planar members 39 . The view taken along section 15 — 15 is unlike the views taken generally oriented to the hypodermic needle holder 11 since directional normal to the general extent of the holder 11 portray the square openings 35 as diamond shape. It is understood that the openings may be oriented differently, such as where each one of the four rectangularly placed planar members 39 are generally parallel to the outer extent of the holder 11 .
Referring again to FIG. 15, recall that behind the rectangularly placed planar members 39 are the plurality of wedge shaped blind bores 37 and it is shown in FIG. 15 in dashed line format. The wedge shape of the plurality of blind bores 37 insures that the injection mold can withdraw in a direction normal to the planar portion 31 and out of the paper, toward the observer with respect to FIG. 6, but the existence of the plurality of blind bores 37 insures that each of the four rectangularly placed planar members 39 can ultimately flex to form a final friction or grabbing action at the extreme mouth of the series of square openings 35 .
The shaped area within the series of square openings 35 should also ideally be ultimately tapered toward the abbreviated end 89 of the openings, else a more complicated mold with moving parts would be necessary to form such an internal shape existing between each square opening 35 and the abbreviated end 89 .
FIG. 15 illustrates a “square on” view of one of the four rectangularly placed planar members 39 . The illustration of the blind bore 37 in dashed line format to the rear emphasizes the wall-like characteristics of the structure in that having a space behind and in front admits to the possibility of some flexing. From the top of the rectangularly placed planar members 39 , a short length of flat wall 141 is seen. From the short length flat wall 141 , an angled transition 143 to the angled surface 85 is seen. The angled surface 85 extends outward, in the direction of the observer, along its length in a direction from the angled transition 143 . The angled surface 85 extends forward at is maximum extent at the bottom of a “bib” shape. Below the angled surface 85 is the curve shaped wall 87 . The curve shaped wall 87 extends outwardly from corners 145 somewhat cylindrically in the direction of the observer of FIG. 15 . Note that the corners 145 extent to the top level of the angled surface 85 and the surfaces of the curved shaped wall are curved even near their uppermost extent where interrupted by the angled surface 85 . Along the length of the curve shaped wall 87 , it tapers in the direction of the observer of FIG. 15 . Below the curve shaped wall 87 , an inner wall 147 of the conical second portion 77 is seen, and which marks a transition to an inwardly curved wall shape.
Referring to FIG. 16, a view taken with regard to line 16 — 16 shows the side profile of the surfaces seen in FIG. 15 and illustrating the lateral extent of the associated surfaces seen at the same level as seen in FIG. 15 . One of the corners 145 is seen in dashed line format. As can be seen, angled surface 85 assists in guiding a needle tip 63 of the hypodermic needle 51 , while the curve shaped wall 87 forms a line of concentration of frictional forces on any rounded object, such as needle hub 53 , along its center between the angled surface 85 and the inner wall 147 . The square nature of the flat wall 141 and the angled surface 85 help engage the square nature of the hub 53 of the hypodermic needle 53 . As such, a transition from square facilitated entry for square turning engagement transitions into a concentrated contact and friction surface interaction with the curve shaped wall 87 . This combination of structures thus facilitates entry, rotational lock and axial frictional engagement.
Referring to FIG. 17, a variation of the hypodermic needle holder of the invention is seen as a hypodermic needle holder 151 which has many of the same structures seen for holder 11 , including a lid portion 153 . However, on lid portion 153 , there is no latch 23 or catch 25 . Rather the lid portion 153 is more closely contour matched to the shape of the opening 15 . Lid portion 153 includes a raised projection 155 about a position just inside of the outer periphery of the lid portion 153 , positioned to enter the opening 15 when the lid portion 153 is closed over the opening 15 . The raised projection 155 may be made to form a more irreversible engagement and seal with respect to the opening 15 when the hypodermic needle holder 151 is closed. In the configuration shown, the outer surface of the raised projection may have a complementary shape matching the inner periphery of the opening 15 to form a snap shut seal. The snap shut mechanism, when combined with the matching peripheral shape, reduces the possibility that the hypodermic needle holder 151 will be inadvertently opened once it is closed.
As can be seen in FIG. 17, a reduced thickness portion 157 is located at the center of a hinge 159 between the lid portion 153 and the opening 15 , to more exactly define the fold of the hinge 159 and to place the raised projection 155 exactly within the opening 15 for a more automatic alignment. Once the raised projection 155 engages the complementery matching surface 161 within the body portion 13 of the opening 15 , a secure snap shut relationship will be had.
FIG. 17 also illustrates a pair of hook arms 165 and 167 extending from the body portion 13 , but also from near the upper end of the tapered flanges 47 , and may be thought of as an extension of the tapered flanges 47 . This enables the hook arms 165 and 167 to garner additional structural strength from the body of the hypodermic needle holder 151 . Hook arms 165 and 167 are also advantageous for enabling the body portion 13 to be hung from the side, as from a tray or cart or box or container, essentially any object which has a vertical wall. Where an object has a thick wall and is vertical, the body portion 13 is likely to hang more upright. On trays with thin walls and more inclined walls, the body portion 13 may hang at a more inclined angle. Any independent support which enables a practitioner to avoid having to support the body portion 13 by hand will significantly reduce incidence of needle stick.
Each of the hook arms 165 and 167 includes a lateral member 171 which estends generally parallel to the top of the body portion 13 , and an opposing member 173 which extends opposite to the lenth of the tapered flange 47 . The taper of the tapered flange 47 compared to the inside of the respective hook arm 165 and 167 causes the opening 15 to tilt somewhat away from any object from which it depends to make the opening 15 more easily available for manual manipulation of hypodermic syringes. The ability to utilize the hypodermic needle holder 151 by independently supporting it, further reduces the chances of a needle stick by removing the user's hand which is not engageding the syringe away from the vicinity of the hypodermic needle holder 151 . It also frees the medical practitioner's other hand for other tasks, not to mention the fact that it frees up tray or table area for other items. Further, the opposing members 173 could be forced through other material such as a box or other paper or cardboard structure to instantly obtain stablility from other weaker objects. As can also be seen, the angle and spacing of the opposing members 173 represents an angular spread which can further assist in affixing the hypodermic needle holder 151 to deformable surface by enabling a progressive tearing action or a pinching action.
Referring to FIG. 18, a further view of hypodermic needle holder 151 is seen. From the left, the side profile of the hook arm 167 is seen. Across the body portion 13 , the thickness of the reduced thickness portion 157 is seen with respect to the center of hinge 159 . A dashed arrow illustrates the radius of closure and is taken with respect to a pivot at the reduced thickness portion 157 .
The side profile of the raised projection 155 is seen to have a laterally extending or laterally thickened projection 181 which is seen in profile as extending generally toward and away from the body portion 13 . In practice, the laterally thickened projection 181 may extend completely about the raised projection 155 , or only partially. A partial extension may, for example, only exist along the side of the raised projection 155 on one of the elongated linear lengths of the raised projection 155 , or two. Or the partial extension may, for example, only exist along the curved sides of the raised projection 155 . Much may depend upon the strength of closure. In addition, the projection may be angled to provide one way, very irreversible closure. In any event, re-opening for purposes of unusual circumstance may still be had with the configuration shown by placing a prying tool into the crack between the body portion 13 and the lid portion 153 .
At the bottom of the hypodermic needle holder 151 , a tear away strip 185 covers a layer of adhesive 187 . Adhesive layer 187 can be located elsewhere, as is shown in FIG. 18, including on one side of the hypodermic needle holder 151 or the other and whether or not on the flanges 47 .
Whether or not there is an available structure with which to engage one or more of the hook arms 165 and 167 , the hypodermic needle holder 151 can be supported by adhesion to any suitable surface. Where the hypodermic needle holder 151 is made of a polymeric substance, the adhesive layer 187 will have high affinity for the bottom surface of the hypodermic needle holder 151 and provide a clean adhesive support for the hypodermic needle holder 151 on any stable surface. After use, and after closure, the hypodermic needle holder 151 can be manually and forceably tipped to one side to disengage it cleanly from any surface. Further, the hypodermic needle holder 151 may be supplied with an accompanying area of plastic base such as a credit card thickness of plastic to use as a further support, especially where there is no clean surface immediately employable for such purpose. Such a support might have an area equivalent to the area of two or three wallet sized credit cards and may be pre-packaged with the hypodermic needle holder 151 as either a package add in or co-molded structure. Where such a base is utilized, the base can be removed and discarded after the hypodermic needle holder 151 use has terminated and after the lid portion 153 is closed over the opening 15 .
The adhesive layer 187 , and hook arms 165 and 167 are but two types of structures for additional support of the hypodermic needle holder 151 , and other structures can be employed. Additional support assists medical practitioners by eliminating the chances and the necessity to bring the practitioner's hands together which has a higher liklihood where the hypodermic needle holder 151 is manually held. Even where manual holding is necessary, manual grasping can occur at the bottom end of the holder 151 , away from the opening 15 .
Although the invention has been derived with reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, included within the patent warranted hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art. | A needle holder has a variety of features that make it an optimal device for safe storage and disposal of hypodermic needles. The needle holder of the present invention includes at least one hypodermic needle retainer for engaging and keeping a hypodermic needle. Further, the needle holder includes a receptacle that may accommodate surgical needles or other small sharps or biologically contaminated articles. The needle holder may be easily and conveniently employed in a variety of settings. Alternative embodiments will accommodate double-ended hypodermic needles, and will also accommodate larger versions of hypodermic needles such as thoracic, cardiac, or spinal needles, and which has additional support provision including hook arms and an adhesive layer. | Identify the most important aspect in the document and summarize the concept accordingly. | [
"This application is a continuation-in-part of U.S. patent application Ser.",
"No. 09/665,636 filed Sep. 19, 2000 now abandoned.",
"FIELD OF THE INVENTION The present invention relates to hypodermic needle holders, suture needle disposal and disposal structures, and more specifically to a hypodermic needle holder and disposal structure that minimizes the risk of inadvertent needle sticks that may result from coupling or uncoupling a hypodermic needle from a hypodermic syringe or recapping a hypodermic needle, or may result from improper storage of a hypodermic needle while the needle is temporarily not in use.",
"BACKGROUND OF THE INVENTION Use and handling of hypodermic needles is a frequent occurrence in the field of medicine.",
"Hypodermic needle systems typically consist of a hypodermic syringe that is quickly and easily removably attachable to a variety of hypodermic needle types and sizes by frictional engagement or by screw-on engagement, the latter of which is usually achieved using a LUERLOCK system.",
"Handling and use of hypodermic needles inherently includes a certain amount of risk of accidental needle stick either to the person who may be administering an injection or to others in the immediate vicinity if a used hypodermic needle is improperly stored or carelessly placed prior to disposal.",
"Recapping a hypodermic needle after an injection is a likely cause of a large percentage of the composite risk factor for needle sticks in health care settings;",
"most institutions discourage recapping of hypodermic needles under any circumstances.",
"In some states and counties, safety laws prohibit recapping and other unsafe disposal practices.",
"Unfortunately, this may also mean that the person responsible for disposing of a used hypodermic needle and syringe may have to travel more than a short distance to reach a sharps disposal container, thereby exposing more people than necessary to the potential hazard of incurring a needle stick and increasing their own risk for injury en route.",
"In some procedures, and for a given patient, there arises the need to re-use a needle during the procedure.",
"For dentists who apply numbing medication in the oral cavity, repeated applications may be required with corresponding re-use of the needle.",
"In other re-anesthetizing uses, such as during suturing, a needle may be re-used.",
"For example, where the tissue requires further, later in time handling of the syringe and needle to either continue anesthization or to move on to another area on the patient's body.",
"In these and many other re-use scenarios, there is simply no proper procedure for interim protection of personnel, isolation of the used and to be used again needle.",
"In some hospitals it is required that a drape cover the sterile field when significant time elapses between a procedure and the next procedure, or where when significant time elapses between a series of procedures.",
"The use of a drape can pick up contamination and spread it with subsequent manipulation of the drape.",
"The drape may catch on the needle or other objects in the sterile field and produce a stick through the drape or even catch the needle and cause it to drop to the floor when the drape is removed.",
"Although the use of the drape to block dust and airborne contaminants, the increased risk of sticks, cuts and upset spills of the materials in the field increase several fold when the drape covers the objects in the field, and there is furter increase of accident each time the drape is handled after its initial deployment.",
"Even systems which are tauted to be “needle-less”",
"continue to create a danger of needle stick.",
"One recent system includes a seventeen gauge tube with a generally blunt (transverse even tubular end) end which is supposed to be protected by a sleeve.",
"If anything, this system is just as apt to create accidental stick contamination as the needle end is hidden until it makes contact with the skin, and the temporary hiding of the needle in the sleeve causes unwarranted reliance on the sleeve with increased carelessness.",
"Further, in health care settings, certain intravenous medications are required to be given in incremented doses and are repeated until a desired effect is achieved.",
"When this is the case, it is not uncommon to repeatedly fill the same hypodermic syringe with medication and to perform repeated intravenous injections into a port that leads directly to a vein or leads into an intravenous fluid line that terminates in a vein.",
"This is usually the case, for example, with patients who have problems of an emergent nature, such as cardiac or respiratory arrest, or problems of an urgent nature such as heart failure or respiratory difficulty, or even for patients undergoing surgery.",
"Because large volumes of fluid may be drawn up into a hypodermic syringe in anticipation of needing them, they are often drawn up using a large gauge hypodermic needle, such as an 18 or even a 16 gauge hypodermic needle for speed and convenience, and this may include the above “needle-less”",
"system.",
"Injecting an intravenous port with such a large gauge hypodermic needle even once could damage the membrane of the port, causing leakage at the port, and thus rendering the entire intravenous tubing useless such that it would have to be replaced.",
"For this reason, administration of intravenous medications typically takes place using a smaller gauge hypodermic needle, usually less than a 20 gauge.",
"This may require that the large gauge needle and the small gauge needle be intermittently exchanged for one another, and certainly requires that whichever needle is not in use be kept from contamination.",
"In dire circumstances, where the patient's condition may be serious and where the environment is likely to be somewhat chaotic as a result, the chances of improper placement of a used hypodermic needle increases significantly.",
"Subsequently, the risk of hypodermic needle contamination increases, as does the risk for inadvertent needle stick for personnel who are caring for the patient, and even for family members or others who may be present.",
"In caring for a patient who receives frequent injections of any kind at the bedside, health care personnel may have their attention diverted from the task at hand by some distraction, and may subsequently place a used hypodermic needle on a bedside table or even on the bed beside the patient in order to address the distraction.",
"Not only could this practice cause unintentional injury to the patient, but health care personnel and others who may have occasion to enter a patient's room after the fact are also at risk of being stuck or otherwise injured by the stray hypodermic needle.",
"Yet another potentially harmful procedure is that of drawing up medications from a vial that requires puncture of a membrane in order to access the medication within the vial.",
"Although the hypodermic needle is not biologically contaminated, this practice still presents the potential for injury to the health care worker or others, since it requires recapping the hypodermic needle until the medication is to be administered.",
"Similarly, medications contained in scored glass vials that require breakage of the vial and drawing up of the medication through a hypodermic needle is another practice that increases risk of needle stick, primarily because of the need for recapping the hypodermic needle prior to giving the injection.",
"A carelessly placed hypodermic needle that causes injury may result in temporary incapacitation of the health care team member who sustains the injury.",
"Prompt treatment of the injury is encouraged by most institutions, and incident reports are mandatory, thereby potentially compromising patient well-being by decreasing the number of staff available for immediate patient care.",
"Yet another potentially injurious situation is that involving hypodermic needle disposal.",
"Disposing of an uncapped hypodermic needle, even into a designated sharps container, can be a dangerous act in itself.",
"Because of the design of most sharps containers, if the container is nearly full, it can prove to be difficult if not impossible to safely insert an exposed hypodermic needle into the box without injury either from the hypodermic needle being inserted or from other needles that may have become lodged in the opening of the box.",
"While hypodermic needles and syringes are likely the cause of most needle stick injuries, surgical needles and other small sharps containers commonly used in a health care setting are also potential hazards if not disposed of properly.",
"Because suture needles are quite small, simple suturing at a patient's bedside may result in misplacement of the small suture needle and attached thread should it not be immediately disposed of or placed in a safe location prior to its disposal.",
"A stray needle in the patient's bed or on the floor could result in patient injury or injury to health care workers, patient family, or others who may come in contact with the patient or who may have occasion to be in the patient's room.",
"Lack of an appropriate disposal container in an operating room could also lead to misplacement of suture needles during a patient's surgery;",
"this could be particularly problematic, and could place the patient in unnecessary danger by delaying the completion of the surgery until all suture needles are located.",
"Other persons at risk for injury from needle stick include family members or unskilled lay persons who may help to care for patients in a home setting and who may regularly assist, for example, with subcutaneous administration of medications such as insulin.",
"Other persons at risk include paramedics and emergency health workers who are always on the move, continually working in harried, difficult conditions and have no prepared surgical field to use as a base of operations.",
"With paramedics, for example, time is of the essence.",
"If too much time is required in either disposing of or temporarily storing a needle, the parametic may toss it on the ground where it may contaminate others or toss it in the medical kit.",
"Without a proper, inviting and very available place to both store needles during extended procedures and to at least safely and temporarily dispose of needles on the move, needle sticks and the like will remain a major problem to emergency health professionals.",
"Yet another situation where accidental needle sticks or other injury can occur is after an intravenous line is initiated on a patient.",
"Because the intravenous catheters used are catheter-over-the needle systems, once the catheter is in place, the needle is extracted and disposed of.",
"Whether the intravenous line is started in an emergency situation that may be chaotic, or whether started in the most optimal of situations, the needle may be improperly placed on whatever surface is nearest at hand so that the catheter may be secured and fluids or medication may be administered.",
"Should the needle be forgotten once the procedure is complete, it will pose a risk for those in the immediate vicinity.",
"Some new catheter systems include safety devices, but use of such devices still involves the needle being left out with continued danger of needle sticks at the point.",
"Although most, if not all, health care institutions have designated procedures for the proper use and disposal of needles, and although most institutions additionally require health care workers to attend continuing education classes for learning safe handling and disposal of sharps and other biologically contaminated equipment, accidental needle sticks continue to occur and are an ongoing problem.",
"The risk of accidental needle stick is cause for serious concern, both to health care workers and to others who may be exposed to the use of hypodermic syringes and needles of any kind, due to the existence and transmissibility of life threatening blood-borne diseases such as hepatitis, and Acquired Immune Deficiency Syndrome (AIDS).",
"What is therefore needed is a device and method that is easy and convenient to use and that will minimize the risk associated with handling and disposal of hypodermic needles and hypodermic syringes.",
"The proposed device should be useable by trained health care personnel, as well as by unskilled lay persons such as patients, family members, and other care givers.",
"The proposed device should be able to accommodate a variety of sharps or similarly small biologically contaminated items that would be ill disposed of in an ordinary trash can.",
"Numerous attempts have been made in the prior art to design a safe disposal container for hypodermic syringes and needles.",
"However, such devices do not allow for both the removal and attachment of hypodermic syringes and needles in a safe manner.",
"Such devices also do not teach their sterilization to enable them to be used in any capacity other than their capacity for disposal.",
"All of the prior devices for holding and facilitating safe disposal of the needles will destroy the sterility of the sterile field.",
"Any health care worker walking about with an open container full of contaminated needles should not be allowed anywhere near a sterile field.",
"Many of the devices are not only too contaminated, they are too large for the sterile field.",
"Most of the prior devices which will accommodate large numbers of syringe needles, by being contaminated, require the health care workers to carry the needles to it, again exacerbating the handling problem and increasing danger to others from open carriage of the contaminated material.",
"In prior devices, no attempt is made to either start with a sterile space nor to isolate stored needles from other needles which have been contaminated by other patients.",
"For example, U.S. Pat. No. 5,046,612 issued to Mostarda et al.",
"and U.S. Pat. No. 4,917,243 issued to Abrams both provide hand held receptacles that extract hypodermic needles from hypodermic syringes.",
"As such the used hypodermic needles are longitudinally placed inside the receptacle and removed from the hypodermic syringe to thereby reduce the risk of injury from the hypodermic needle tip.",
"Both inventions provide different means for inserting the hypodermic needle into the receptacle longitudinally such that the risk of exposure to the sharpened hypodermic needle tip is reduced.",
"However, there are no methods for reusing the hypodermic needle as is necessary when re-filling a hypodermic syringe with fluid or medication or re anesthetizing a patient, or re-injection of a joint.",
"In U.S. Pat. No. 5,057,656 issued to Galber, a disposal container for hypodermic needles is provided.",
"The container includes a top with suitability shaped openings for the removal of hypodermic needles from hypodermic syringes.",
"Used hypodermic needles are disposed inside the container to protect the health care worker.",
"Also, the needles inserted into the foam filled container can't be reversed and used again as foam fills the needle opening.",
"Furthermore, in U.S. Pat. No. 4,375,849 issued to Nahifl and U.S. Pat. No. 4,351,434 issued to Elisha, hypodermic needles are disposed in a cylindrical container through an opening in the container top.",
"However, such containers pose a risk of injury to the health care worker because the container is usually held with a hand that can be punctured by the exposed hypodermic needle tip as it is inserted into the container.",
"As such, these containers do not provide a safe method of disposal.",
"Similarly, U.S. Pat. No. 4,995,871 issued to Sasaki et al.",
"And U.S. Pat. No. 4,984,686 issued to Shillington provide enclosure lids that extract the hypodermic needle from the hypodermic syringe and then dispose of the hypodermic needle in an attached container.",
"However, both devices are complex and not easily manufactured and do not provide for the safe storage of exposed hypodermic needle tips.",
"Additionally, U.S. Pat. No. 4,892,191 issued to Nakamura, discloses a container for the removal and disposal of press or slip type hypodermic needles attached to a hypodermic syringe while U.S. Pat. No. 4,802,579 issued to Hall et al.",
"discloses a container which removes and disposes of hypodermic needles that use screw threads to attach the hypodermic syringe.",
"In both devices, the hypodermic needle is inserted into the disposal container through an opening and engaged thereby.",
"The opening is then used to remove the hypodermic needle from the hypodermic syringe and the exposed hypodermic needle is dropped down into the container.",
"However, neither of these devices provide means for storing the exposed hypodermic needles while being attached or removed from the hypodermic syringe before being disposed.",
"Furthermore, U.S. Pat. No. 4,191,264 issued to Shinall discloses a removal and disposal device for hypodermic needles.",
"The device comprises individual containers that remove and store the used hypodermic needle in a tacky substance.",
"As such, the device is complicated and expensive to manufacture and does not allow needle re-use.",
"Similarly, U.S. Pat. No. 4,452,358 discloses a box-like device wherein the hypodermic needle is destroyed while being removed from the hypodermic syringe and the container includes multiple compartments and openings for the disposal of other medical instruments such as scalpel blades.",
"As can be seen from the related prior art, numerous devices have been designed for the disposal of hypodermic syringes and needles.",
"However, none of the prior art devices provide an apparatus that can safely remove, attach and store the hypodermic needle and then properly dispose of the hypodermic needle after use.",
"What is therefore needed is an inexpensive device that protects the health care worker from inadvertent needle sticks while handling hypodermic needles and syringes.",
"The needed device and method should be simple to use and therefore optimal for use by both trained professional health care workers as well as unskilled lay persons who may have need of using hypodermic syringes and needles in a home care setting.",
"Additionally, there exists a need for provision of both storage of hypodermic needles, with or without a hypodermic syringe attached, and for disposal of hypodermic needles quickly and safely after their use and subsequent detachment from hypodermic syringes.",
"Furthermore, there is a need for containment and disposal of other sharp objects such as suture needles, or other small items that may be biologically contaminated and that would be more appropriately disposed of in a biological waste container rather than in a trash can.",
"SUMMARY OF THE INVENTION The needle holder of the present invention has a variety of features that make it an optimal device for safe storage and disposal of hypodermic needles.",
"Further, the needle holder of the present invention is also able to accommodate surgical needles or other small sharps or biologically contaminated articles, and may be easily and conveniently employed in a variety of settings.",
"Alternative embodiments of the present invention will accommodate double-ended hypodermic needles, and larger versions of hypodermic needles such as thoracic, cardiac, or spinal needles.",
"In the preferred embodiment of the present invention, there is provided a hypodermic needle holder which works with a hypodermic needle having a needle hub adjacent a needle shaft and terminating at a needle tip.",
"The hypodermic needle holder comprises a body portion and a lid portion, the body portion of which defines a compartment having a plurality of needle retainers disposed in a side-by-side relation therein.",
"The needle retainers are sized and configured to frictionally engage the needle hub of a hypodermic needle in a manner wherein the hypodermic needle is fixedly contained within the needle retainer.",
"The needle retainers are frustoconical or conically or of tapering shape and also specially internally shaped for frictional retention of the hypodermic needles.",
"The compartment has a generally rectangular configuration and is optimally formed from a rigid and durable plastic material.",
"The lid portion of the hypodermic needle holder is moveable between an open position where the needle retainers are accessible and a closed position whereat the needle retainers are shielded within the hypodermic needle holder.",
"The hypodermic needle holder of the present invention also includes a receptacle into which smaller sized needles such as surgical needles may be placed after use.",
"Furthermore, this receptacle may be used for small items such as cotton balls, gauze pads, or discontinued intravenous catheters that may be biologically contaminated and that would be best disposed of in a bio-hazardous waste container.",
"The material from which the needle holder may be constructed may be clear in order to facilitate a visual count of suture needles as well as a count of engaged and stored hypodermic needles.",
"In an alternative embodiment of the present invention, the size of the overall hypodermic needle holder and of the needle retainers themselves are elongated in order to contain longer hypodermic needles such as cardiac, thoracic, or spinal needles.",
"In yet another alternative embodiment of the present invention, a container is provided with a slightly larger opening in order to accommodate a double ended hypodermic needle such as those used in many dental practices, as well as those used in the medical profession primarily by phlebotomists and in conjunction with devices such as VACUTAINERS.",
"Further there is provided a method for transferring attachment of a hypodermic needle to or from a hypodermic syringe through the use of a hypodermic needle holder which includes an opening with at least one engaging needle retainer disposed therein.",
"The method includes frictionally engaging the hypodermic needle to the needle retainer both by insertion friction and turning friction.",
"The hypodermic syringe is advanced into the opening of a hypodermic needle holder and subsequently into a needle retainer space and retainer structure for initial axial frictional engagement to cause the hypodermic needle to be frictionally engaged with the retainer structure.",
"The hypodermic syringe can be disengaged from the hypodermic needle by a turning motion against the friction and locking holding power of the needle retainer, to disengage the needle from its LUER fitting.",
"The hypodermic syringe can be re-engaged onto the hypodermic needle by approach of the syringe, and physical engagement of the LUER fitting by a turning motion against the friction and locking holding power of the needle retainer, to re-engage the LUER fitting.",
"Once re-engaged, a simple axial pulling of the syringe and LUER attached needle will disengage the hypodermic needle from the needle retainer.",
"If needed, the hypodermic needle and syringe combination can be disengaged from the needle retainer and removed from the opening of the hypodermic needle holder for further use.",
"By providing a relatively larger structure than a simple cap, movement of the hypodermic needle into and from its storage area is accomplished while the fingers and hand not holding the hypodermic syringe can support the hypodermic needle holder significantly far from the area of entrance of the needle into the hypodermic needle holder.",
"Furthermore, the hypodermic needle holder includes an openable and closable lid portion for selectively accessing the needle retainer wherein the lid portion must be opened prior to advancing the hypodermic syringe into the opening of the hypodermic needle holder.",
"The present invention further includes a method of removing a hypodermic needle from a hypodermic syringe that includes a hypodermic needle holder having an opening with at least one needle retainer disposed therein.",
"The method comprises advancing a hypodermic syringe with a hypodermic needle coupled thereto into the hypodermic needle holder and subsequently into the needle retainer.",
"Next, the hypodermic needle is frictionally engaged to the needle retainer.",
"The hypodermic syringe is then uncoupled from the hypodermic needle, leaving the hypodermic needle engaged within the needle retainer.",
"The hypodermic syringe and needle may be coupled via a frictional engagement wherein uncoupling the hypodermic syringe from the hypodermic needle comprises pulling the hypodermic syringe away from the hypodermic needle.",
"Alternatively, the hypodermic syringe and needle may be coupled via a LUER fitting such that uncoupling the hypodermic syringe from the hypodermic needle comprises rotation of the hypodermic syringe to disengage the hypodermic needle.",
"Furthermore, the hypodermic needle holder includes a lid portion such that the lid portion must be opened prior to the advancement of the hypodermic syringe into the hypodermic needle holder.",
"BRIEF DESCRIPTION OF THE DRAWINGS The invention, its configuration, construction, and operation will be best further described in the following detailed description, taken in conjunction with the accompanying drawings in which: FIG. 1 is a view of the hypodermic needle holder of the present invention, and illustrates a body portion that defines a compartment having a receptacle at one side and a plurality of needle retainers adjacent the end receptacle, and a lid portion in an open position and with a cantilevered latch connected to the body portion and;",
"FIG. 2 is a perspective expanded view of a hypodermic needle and illustrates a hub adjacent a needle shaft with a beveled edge that terminates at a needle tip.",
"FIG. 3 is a view of more of the needle support structure of the hypodermic needle holder of FIG. 1 from an elevated perspective and illustrates the overall shape and position of the receptacle and the plurality of needle retainers, and the attachment of the lid portion in an open position with cantilevered latch;",
"FIG. 4 is a view of the bottom of the hypodermic needle holder of FIGS. 1 and 3 and illustrates the body portion, the extent of the structural support as an “H”",
"overall shape, the position of the receptacle and needle retainers, and the lid portion in an open position;",
"FIG. 5 is a side view of the hypodermic needle holder of FIGS. 1, 3 , and 4 that best illustrates the overall shape and side-by-side orientation of the receptacle and plurality of needle retainers, and clearly illustrates the cantilevered latch extending from the lid;",
"FIG. 6 is a view of the top of the hypodermic needle holder of FIGS. 1, 3 , 4 , and 5 and illustrates the body portion, the position of the receptacle and needle retainers, and the lid portion in an open position with single body hinge and cantilevered latch;",
"FIG. 7 is an expanded view along line 7 of FIG. 6 that illustrates in more detail the configuration of each of the plurality of needle retainers;",
"FIG. 8 is a cross-sectional view along line 8 — 8 of FIG. 6 and more clearly illustrates the body of the hypodermic needle holder and the position of the receptacle and plurality of needle retainers therein;",
"FIG. 9 is a cross-sectional view along line 9 — 9 of FIG. 5 and more clearly illustrates one of the plurality of needle retainers and its position relative to the body portion, lid portion, and cantilevered latch thereon the lid portion;",
"FIG. 10 is an expanded view along line 10 of FIG. 9 that illustrates in detail a catch on the cantilevered latch on the lid portion of the hypodermic needle holder;",
"FIG. 11 is a cross-sectional view along line 11 — 11 of FIG. 5 that more closely illustrates the overall shape of the receptacle and its position relative to the lid portion of the hypodermic needle holder;",
"FIG. 12 is an expanded view along line 12 of FIG. 11 that illustrates a bifurcation in the lid portion to allow for movement of the lid portion;",
"FIG. 13 is a top view of a second embodiment of the hypodermic needle holder configured to accommodate a pair of double-ended needles such as dental needles or needles used for phlebotomy;",
"FIG. 14 is a side view of the second embodiment of the needle holder with an elongated needle accommodation portion utilizable for longer needles, such as cardiac needles, and further illustrating a double-ended needle for illustration purposes;",
"FIG. 15 is a view taken along section 15 — 15 of FIG. 7 and illustrating a frontal view of one of side of the four square openings from the top of one of its four flat inner walls and proceeding downwardly into the needle accommodation chamber and particularly illustrating a slanted bib surface which transitions into an inwardly curved surface and which finally transitions to a generally straight angled frustoconical surface;",
"FIG. 16 is a side view as seen in FIG. 15 and illustrating the lateral extent of the associated surfaces seen at the same level as seen in FIG. 15;",
"FIG. 17 is a perspective view of a further embodiment of the hypodermic needle holder having a positive lock lid which is tamper resistant, and having outwardly and downwardly extending projections to independently stabilize the holder;",
"and FIG. 18 is a side view and illustrating further details of the embodiment of FIG. 17 and including a peel strip for attaching the holder to another surface.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The description and operation of the hypodermic needle holder of the invention will be best described with reference to FIG. 1 .",
"The hypodermic needle holder 11 includes a body portion 13 having an upper wall 14 that defines an opening 15 .",
"Note that while the overall shape of the opening 15 of the hypodermic needle holder 11 in the preferred embodiment is elongate oval, a variety of shapes is possible without compromise of functionality, such as rectangular, rectangular with curved edges, and the like.",
"The opening 15 is enclosable by a lid portion 21 adjacent the opening 15 of the body portion 13 .",
"The lid portion 21 has a cantilever operated latch 23 adjacent a rectangular opening 24 and attached from the lid portion 21 .",
"Cantilever operated latch 23 terminates in a right angled extension to form a catch 25 .",
"The body portion 13 , attached to the lid portion 21 further defines a planar portion 31 , within the space beyond the opening 15 , having a single circular opening 33 and a series of generally square openings 35 , each of the series of square openings 35 are in turn surrounded by a plurality of tapered blind bores 37 , separated by a series of four rectangularly placed planar members 39 .",
"Each of the series of square openings 35 is arranged in a side-by-side configuration with each of the others in the series of square openings 35 , and with respect to the single circular opening 33 .",
"This arrangement is not exhaustive of the spatial arrangements possible, but in the preferred embodiment of the hypodermic needle holder 11 it does have a low profile in one dimension to facilitate disposal in a sharps container having a narrow opening.",
"The single circular opening 33 in the planar portion 31 leads into a frustoconical shaped receptacle 43 defined by the body portion 13 of the hypodermic needle holder 11 for containment and eventual disposal of small sharps such as surgical needles, or small biologically contaminated items such as cotton balls, gauze squares, or even discontinued intravenous catheters.",
"Each of the series of square openings 35 leads into a corresponding one of a plurality of needle retainers 45 defined by the body portion 13 of the hypodermic needle holder 11 .",
"The frustoconically shaped receptacle 43 and plurality of needle retainers 45 are arranged such that their longitudinal axes are parallel with one another in order to save space.",
"The axes of the frustoconical receptacle 43 and plurality of needle retainers 45 are arranged generally parallel with the general longitudinal extent of the holder 11 .",
"The axes of the frustoconical receptacle 43 , and plurality of needle retainers 45 are perpendicular to the planar portion 31 .",
"The hypodermic needle holder 11 may be optimally constructed from a durable but slightly flexible material such as injection molded plastic, that will allow some radially outwardly displacement of each planar member 39 forming each wall of the square of the series of square openings 35 and into the area of each of the plurality of blind bores 37 .",
"Any radially outward displacement as a result of inserting a needle (illustrated in FIG. 2) provides an inward grip, in addition to the spatial engagement of the square shape of the planar members on the square aspects of a needle.",
"Construction of the hypodermic needle holder 11 from such a slightly flexible material will thus result in a displacement based inward biasing of the material toward the hub of the needle (illustrated in FIG. 2) for enhancing the frictional engagement and trapping of the needle within the hypodermic needle holder 11 .",
"The body portion 13 of the hypodermic needle holder 11 also defines four tapered flanges 47 extending away from the end of the holder 11 adjacent the opening 15 , and arranged such that each of two pairs of tapered flanges 47 is disposed at opposite lateral sides of the hypodermic needle holder 11 , with one of each pair oppositely disposed from the other of each pair.",
"The tapered flanges 47 help to stabilize the hypodermic needle holder 11 during upright placement on a planar surface such as a table, as well as provide overall structural strength and integrity.",
"FIG. 2 is a view of a hypodermic needle 51 having a needle hub 53 with opening 55 surrounded by a square flange member 56 to complete a LUER fitting.",
"Between the hub 53 and a needle shaft 57 , is a series of four projecting ribs 59 which give the lower part of the hub 53 a square profile to provide a rotational lock with respect to the planar members 39 forming each wall of the square of the series of square openings 35 .",
"Each of the projecting ribs 59 will fit at a corner of the junction of each of the planar members 39 to provide a square rotational lock, in addition to the frictional engagement from axial insertion of the hypodermic needle.",
"Needle shaft 57 has a beveled edge 61 that terminates at a needle tip 63 .",
"FIG. 3 is a perspective view of the reverse side of the hypodermic needle holder 11 , with respect to the perspective view of FIG. 1 from an elevated perspective and further illustrates the lid portion 21 as having one or more bifurcations 71 adjacent the body portion 13 and extending across the full width of the lid portion 21 at its connection to the body portion 13 .",
"The bifurcation 71 may preferably be a thinning of the material in order to direct and control the lid portion 21 to close in a mating relationship over the opening 15 .",
"Further, the bifurcation or bifurcations 71 allow a user to manually and orderly open the lid portion 21 in order to gain access to the needle retainers 45 or frustoconical receptacle 43 , or to close the lid portion 21 in order to enclose the contents of the frustoconical receptacle 43 and the plurality of needle retainers 45 for safety or for containment of biologically contaminated items.",
"Ideally, the hypodermic needle holder 11 of the present invention would be constructed of a durable, yet somewhat flexible material such as plastic, to allow for movement of the lid portion 21 without breakage at the bifurcation 71 .",
"One material of construction is polypropylene.",
"The bifurcation 71 has sometimes been known as a living hinge, and can be formed by controlling the thickness and width of its extent.",
"The body portion 13 of the hypodermic needle holder 11 defines an interstitial planar web structure 73 extending between and radially perpendicular to each of the plurality of needle retainers 45 and frustoconical receptacle 43 .",
"The interstitial planar web structure 73 as a plane within which the axes of the plurality of needle retainers 45 and frustoconical receptacle 43 reside, thus enhancing the overall structural stability and particularly the upright stability of the hypodermic needle holder 11 .",
"FIG. 3 further illustrates that each of the plurality of needle retainers 45 comprises a square opening 35 adjacent a chamber 74 having a tapering or frustoconical first portion 75 adjacent a conical or tapering second portion 77 .",
"FIG. 4 is a view of the bottom of the hypodermic needle holder 11 of FIGS. 1 and 3 and illustrates the lid portion 21 in an open position with attached cantilevered latch 23 and catch 25 (both illustrated in phantom) for securing the lid portion 21 in a closed position.",
"FIG. 4 also illustrates the body portion 13 , the frustoconical receptacle 43 and the plurality of needle retainers 45 , each in side-by-side orientation with one another.",
"Also illustrated herein are the tapered flanges 47 defined by the body portion 13 , and the bifurcation or bifurcations 71 in the lid portion 21 of the hypodermic needle holder that allows for and directs the movement of the lid portion 13 for opening or closing the lid portion 13 .",
"FIG. 4 also illustrates the interstitial planar web structure 73 and better details its position in the plane formed by the longitudinal axes of the frustoconical receptacle 43 and plurality of needle retainers 45 .",
"FIG. 4 illustrates in phantom format the opening 15 defined by the body portion 13 .",
"FIG. 5 is a side view of the hypodermic needle holder of FIGS. 1, 3 , and 4 .",
"FIG. 5 illustrates the frustoconical receptacle 43 in side-by-side alignment with the plurality of needle retainers 45 , and also clearly illustrates the frustoconical first portion 75 adjacent the tapering second portion 77 of each of the chambers 74 .",
"Also illustrated in phantom in FIG. 5 is the opening 15 defined by the wall 14 of the body portion 13 of the hypodermic needle holder 11 .",
"The lid portion 21 is illustrated in an open position out of the plane of the page, with cantilevered latch 23 shown and catch 25 illustrated in phantom.",
"The interstitial planar web structure 73 as well as the two of the four tapered flanges 47 is also clearly seen in FIG. 5 .",
"FIG. 6 is a view of the top of the hypodermic needle holder 11 of FIGS. 1, 3 , 4 , and 5 and illustrates the lid portion 21 in an open position and with attached cantilevered latch 23 and catch 25 for securing the lid portion 21 in a closed position.",
"FIG. 6 illustrates the body portion 13 , the opening 15 defined by the body portion 13 , the planar portion 31 , the single circular opening 33 adjacent the frustoconical receptacle 43 , and the series of square openings 35 , each surrounded by plurality of blind bores 37 , separated from the square openings 35 by series of four rectangularly placed planar members 39 and each of which is adjacent one of the plurality of needle retainers 45 .",
"Two of the tapered flanges 47 defined by the body portion 13 are also be seen in FIG. 6 .",
"Finally, FIG. 6 illustrates in phantom the bifurcation 71 in the lid portion 21 of the hypodermic needle holder 11 that allows for movement of the lid portion 13 .",
"The birfucation 71 could have been placed on either side of the lid portion 13 , or a pair of oppositely located shallow bifurcations could have been placed on opposite sides of the lid portion 13 , and the phantom showing is for consistency only.",
"The main idea is some structure which guides folding.",
"FIG. 7 is an expanded view along line 7 of FIG. 6 and further details the configuration of one of the plurality of needle retainers 45 .",
"FIG. 7 illustrates a section of the planar portion 31 having one of the series of square openings 35 surrounded by plurality of blind bores 37 and separated by the series of four rectangularly placed planar members 39 .",
"Immediately inside the square opening 35 , the needle retainer 45 has four flat inner walls 83 which are immediately adjacent each the series of four rectangularly placed planar members 39 .",
"Below the four flat inner walls, a beveled surface angled surface 85 sloping downward into a curve shaped wall 87 .",
"The lateral extent of the angled surface 85 has a curved shape which permits the curved shaped wall 87 to lie adjacent the four flat inner walls 83 at the ends of the curved shaped wall adjacent the corners formed by the four flat inner walls 83 .",
"The curve shaped wall 87 concentrates the contact area slightly for a more friction laden engagement with the needle hub 53 .",
"The chamber 74 has a tapering shape leading to an abbreviated end 89 .",
"The angled surface 85 has an adjacent shape as an upwardly open parabolic shape.",
"The beveled surface is a shape consistent with the early extent of a diminishing tapered radius, and finally terminates on the frustoconical first portion 75 of inside of the chamber 74 of the needle retainer 45 .",
"Note that the bounds of the convexity of the curve shaped wall 87 define an inwardly curving shape.",
"During use, hypodermic needle 51 is inserted into the square opening 35 and is advanced toward the adjacent frustoconical first portion 75 and subsequent tapering second portion 77 of the chamber 45 so that the ribs 59 begin to place the hypodermic needle 51 in a position where it is limited in turning about its axis.",
"Continued insertion causes the needle hub 53 to contact the curve shaped walls 87 within the frustoconical first portion 75 of the chamber 74 .",
"As the needle hub 53 advances into the square opening 35 , the needle hub 53 will pass over the four flat inner walls 83 , angled surface 85 , and the curve shaped wall 87 .",
"Once frictional engagement occurs, the four flat inner walls 83 may be slightly outwardly displaced to provide more frictional grasping of the needle hub 53 , especially at the middle, innermost aspect of the curve shaped walls 87 below the angled surface 85 .",
"While the hypodermic needle 51 is in place with respect to the holder 11 , a syringe to which it is attached can be twisted to de-couple the LUER fitting to free the syringe, or the syringe can be brought again to the LUER fitting and twisted to re-couple the syringe to the hypodermic needle 51 .",
"Withdrawal of the hypodermic needle 51 from the hypodermic needle holder 11 can then accomplished by a frictional extraction of the hypodermic needle 51 from the needle holder 11 .",
"FIG. 8 is a cross-sectional view of the hypodermic needle holder 11 taken along line 8 — 8 of FIG. 6 that illustrates the body portion 13 , the opening 15 defined by the body portion 13 , the cantilevered latch 23 with catch 25 , the frustoconical receptacle 43 , and the plurality of needle retainers 45 .",
"The series of interstitial planar web structure 73 are illustrated as shaded in this figure.",
"FIG. 9 is a cross-sectional view taken along line 9 — 9 of FIG. 5 that more closely illustrates one of the plurality of needle retainers 45 of the hypodermic needle holder 11 .",
"Visible is the body portion 13 , two of the tapered flanges 47 , the frustoconical receptacle 43 , the lid portion 21 , the cantilevered latch 23 with catch 25 , the bifurcation 71 in the lid portion 21 , the opening 15 defined by the body portion 13 , and the square opening 35 , frustoconical first portion, and conical second portion of the chamber 74 .",
"A flat underside surface 91 lies adjacent and just adjacent wall 14 .",
"Flat underside surface 91 forms a right angle with respect to the outside of wall 14 .",
"FIG. 10 is an expanded view along line 10 — 10 of FIG. 9 that illustrates in close detail the catch 25 of the cantilevered latch 23 of the hypodermic needle holder 11 extending at a right angle to one side and having a flat portion 93 which will contact and complementarily fit the flat underside surface 91 to enable the lid portion 21 to be locked over the opening 15 to form an enclosure from which any hypodermic needles 51 cannot escape.",
"Typically, the lid portion 21 will be closed and locked at one time, usually just before disposal.",
"FIG. 11 is a cross-sectional view taken along line 11 — 11 of FIG. 5 that more closely illustrates the frustoconical receptacle 43 and single circular opening 33 of the hypodermic needle holder 11 .",
"In FIG. 11, the body portion 13 , opening 15 defined thereby, lid portion 21 , and bifurcation 71 therein may easily be seen.",
"FIG. 12 is an expanded view along line 12 — 12 of FIG. 11 that more closely details the bifurcation 71 of the lid portion 21 .",
"As has been observed, the bifurcation in this case is a thinning of the material and such thinning can occur on either or both sides of the lid portion.",
"Multiple thinned areas can be used in order to control the bending of the material to form a hinge.",
"FIG. 13 is a top view of a second embodiment of the hypodermic needle holder as a holder 101 configured to accommodate a pair of double-ended needles such as dental needles or needles used in conjunction with VACUTAINERS for phlebotomy.",
"In this embodiment of the hypodermic needle holder 101 , the diameters of the series of square openings 35 of the needle retainers 45 are sized larger to accommodate a larger needle hub (illustrated in FIG. 14 ).",
"This embodiment of the hypodermic needle holder 11 may be utilized anywhere, but may be best suited for health care facilities such as dentist's offices, laboratories, mobile blood banks, and other locations where use of a double-ended hypodermic needle is common.",
"A further embodiment of the hypodermic needle holder is seen as holder 111 and is seen in FIG. 14 .",
"The overall size of the hypodermic needle holder 111 for cardiac and other elongate needles is itself longer.",
"Cantilevered latch 23 and catch 25 , the body portion 13 , the opening 15 defined thereby, and two of the tapered flanges 47 may also be seen in this figure.",
"Finally, the lid portion 21 is illustrated in phantom in FIG. 14 .",
"FIG. 14 further illustrates, as an example, a double-ended hypodermic needle 113 .",
"Double ended hypodermic needle 91 has a first needle shaft 115 terminating in a first needle tip 117 at one end and adjacent a needle hub 119 at an opposite end.",
"The needle hub is adjacent one end of a second needle shaft 121 that is typically longer in length than the first needle shaft 115 and that terminates in a second needle tip 123 at an opposite end.",
"FIG. 14 best illustrates the heightened size of the second embodiment of the hypodermic needle holder 11 to provide for accommodation of a double-ended needle 91 such as the one illustrated herein.",
"In FIG. 14, the proper position of double-ended needle 113 for insertion into the hypodermic needle holder 111 is shown.",
"Note that the hypodermic needle holder 11 may be also be manufactured sized to fit any length of hypodermic needle such as thoracic, cardiac, or spinal needles.",
"The double-ended needle 113 is shown attached to a syringe 131 and is especially preferable to use the syringe 131 for insertion of doubled-ended needles for safety.",
"The hypodermic needle holder 11 has an unusual shape within its series of square openings 35 .",
"The shape is intended to simultaneously (1) provde easy entry with minimum restriction, (2) provide a square engagement, and upon further insertion (3) provide a frictional hold by concentrating force on a relatively limited amount of common structure/material in order to obtain a frictional hold on the hypodermic needle 51 .",
"FIG. 15 is a view taken along section 15 — 15 of FIG. 7 and illustrating a frontal view of one of side of the four square openings 35 from the top of one of the four rectangularly placed planar members 39 .",
"The view taken along section 15 — 15 is unlike the views taken generally oriented to the hypodermic needle holder 11 since directional normal to the general extent of the holder 11 portray the square openings 35 as diamond shape.",
"It is understood that the openings may be oriented differently, such as where each one of the four rectangularly placed planar members 39 are generally parallel to the outer extent of the holder 11 .",
"Referring again to FIG. 15, recall that behind the rectangularly placed planar members 39 are the plurality of wedge shaped blind bores 37 and it is shown in FIG. 15 in dashed line format.",
"The wedge shape of the plurality of blind bores 37 insures that the injection mold can withdraw in a direction normal to the planar portion 31 and out of the paper, toward the observer with respect to FIG. 6, but the existence of the plurality of blind bores 37 insures that each of the four rectangularly placed planar members 39 can ultimately flex to form a final friction or grabbing action at the extreme mouth of the series of square openings 35 .",
"The shaped area within the series of square openings 35 should also ideally be ultimately tapered toward the abbreviated end 89 of the openings, else a more complicated mold with moving parts would be necessary to form such an internal shape existing between each square opening 35 and the abbreviated end 89 .",
"FIG. 15 illustrates a “square on”",
"view of one of the four rectangularly placed planar members 39 .",
"The illustration of the blind bore 37 in dashed line format to the rear emphasizes the wall-like characteristics of the structure in that having a space behind and in front admits to the possibility of some flexing.",
"From the top of the rectangularly placed planar members 39 , a short length of flat wall 141 is seen.",
"From the short length flat wall 141 , an angled transition 143 to the angled surface 85 is seen.",
"The angled surface 85 extends outward, in the direction of the observer, along its length in a direction from the angled transition 143 .",
"The angled surface 85 extends forward at is maximum extent at the bottom of a “bib”",
"shape.",
"Below the angled surface 85 is the curve shaped wall 87 .",
"The curve shaped wall 87 extends outwardly from corners 145 somewhat cylindrically in the direction of the observer of FIG. 15 .",
"Note that the corners 145 extent to the top level of the angled surface 85 and the surfaces of the curved shaped wall are curved even near their uppermost extent where interrupted by the angled surface 85 .",
"Along the length of the curve shaped wall 87 , it tapers in the direction of the observer of FIG. 15 .",
"Below the curve shaped wall 87 , an inner wall 147 of the conical second portion 77 is seen, and which marks a transition to an inwardly curved wall shape.",
"Referring to FIG. 16, a view taken with regard to line 16 — 16 shows the side profile of the surfaces seen in FIG. 15 and illustrating the lateral extent of the associated surfaces seen at the same level as seen in FIG. 15 .",
"One of the corners 145 is seen in dashed line format.",
"As can be seen, angled surface 85 assists in guiding a needle tip 63 of the hypodermic needle 51 , while the curve shaped wall 87 forms a line of concentration of frictional forces on any rounded object, such as needle hub 53 , along its center between the angled surface 85 and the inner wall 147 .",
"The square nature of the flat wall 141 and the angled surface 85 help engage the square nature of the hub 53 of the hypodermic needle 53 .",
"As such, a transition from square facilitated entry for square turning engagement transitions into a concentrated contact and friction surface interaction with the curve shaped wall 87 .",
"This combination of structures thus facilitates entry, rotational lock and axial frictional engagement.",
"Referring to FIG. 17, a variation of the hypodermic needle holder of the invention is seen as a hypodermic needle holder 151 which has many of the same structures seen for holder 11 , including a lid portion 153 .",
"However, on lid portion 153 , there is no latch 23 or catch 25 .",
"Rather the lid portion 153 is more closely contour matched to the shape of the opening 15 .",
"Lid portion 153 includes a raised projection 155 about a position just inside of the outer periphery of the lid portion 153 , positioned to enter the opening 15 when the lid portion 153 is closed over the opening 15 .",
"The raised projection 155 may be made to form a more irreversible engagement and seal with respect to the opening 15 when the hypodermic needle holder 151 is closed.",
"In the configuration shown, the outer surface of the raised projection may have a complementary shape matching the inner periphery of the opening 15 to form a snap shut seal.",
"The snap shut mechanism, when combined with the matching peripheral shape, reduces the possibility that the hypodermic needle holder 151 will be inadvertently opened once it is closed.",
"As can be seen in FIG. 17, a reduced thickness portion 157 is located at the center of a hinge 159 between the lid portion 153 and the opening 15 , to more exactly define the fold of the hinge 159 and to place the raised projection 155 exactly within the opening 15 for a more automatic alignment.",
"Once the raised projection 155 engages the complementery matching surface 161 within the body portion 13 of the opening 15 , a secure snap shut relationship will be had.",
"FIG. 17 also illustrates a pair of hook arms 165 and 167 extending from the body portion 13 , but also from near the upper end of the tapered flanges 47 , and may be thought of as an extension of the tapered flanges 47 .",
"This enables the hook arms 165 and 167 to garner additional structural strength from the body of the hypodermic needle holder 151 .",
"Hook arms 165 and 167 are also advantageous for enabling the body portion 13 to be hung from the side, as from a tray or cart or box or container, essentially any object which has a vertical wall.",
"Where an object has a thick wall and is vertical, the body portion 13 is likely to hang more upright.",
"On trays with thin walls and more inclined walls, the body portion 13 may hang at a more inclined angle.",
"Any independent support which enables a practitioner to avoid having to support the body portion 13 by hand will significantly reduce incidence of needle stick.",
"Each of the hook arms 165 and 167 includes a lateral member 171 which estends generally parallel to the top of the body portion 13 , and an opposing member 173 which extends opposite to the lenth of the tapered flange 47 .",
"The taper of the tapered flange 47 compared to the inside of the respective hook arm 165 and 167 causes the opening 15 to tilt somewhat away from any object from which it depends to make the opening 15 more easily available for manual manipulation of hypodermic syringes.",
"The ability to utilize the hypodermic needle holder 151 by independently supporting it, further reduces the chances of a needle stick by removing the user's hand which is not engageding the syringe away from the vicinity of the hypodermic needle holder 151 .",
"It also frees the medical practitioner's other hand for other tasks, not to mention the fact that it frees up tray or table area for other items.",
"Further, the opposing members 173 could be forced through other material such as a box or other paper or cardboard structure to instantly obtain stablility from other weaker objects.",
"As can also be seen, the angle and spacing of the opposing members 173 represents an angular spread which can further assist in affixing the hypodermic needle holder 151 to deformable surface by enabling a progressive tearing action or a pinching action.",
"Referring to FIG. 18, a further view of hypodermic needle holder 151 is seen.",
"From the left, the side profile of the hook arm 167 is seen.",
"Across the body portion 13 , the thickness of the reduced thickness portion 157 is seen with respect to the center of hinge 159 .",
"A dashed arrow illustrates the radius of closure and is taken with respect to a pivot at the reduced thickness portion 157 .",
"The side profile of the raised projection 155 is seen to have a laterally extending or laterally thickened projection 181 which is seen in profile as extending generally toward and away from the body portion 13 .",
"In practice, the laterally thickened projection 181 may extend completely about the raised projection 155 , or only partially.",
"A partial extension may, for example, only exist along the side of the raised projection 155 on one of the elongated linear lengths of the raised projection 155 , or two.",
"Or the partial extension may, for example, only exist along the curved sides of the raised projection 155 .",
"Much may depend upon the strength of closure.",
"In addition, the projection may be angled to provide one way, very irreversible closure.",
"In any event, re-opening for purposes of unusual circumstance may still be had with the configuration shown by placing a prying tool into the crack between the body portion 13 and the lid portion 153 .",
"At the bottom of the hypodermic needle holder 151 , a tear away strip 185 covers a layer of adhesive 187 .",
"Adhesive layer 187 can be located elsewhere, as is shown in FIG. 18, including on one side of the hypodermic needle holder 151 or the other and whether or not on the flanges 47 .",
"Whether or not there is an available structure with which to engage one or more of the hook arms 165 and 167 , the hypodermic needle holder 151 can be supported by adhesion to any suitable surface.",
"Where the hypodermic needle holder 151 is made of a polymeric substance, the adhesive layer 187 will have high affinity for the bottom surface of the hypodermic needle holder 151 and provide a clean adhesive support for the hypodermic needle holder 151 on any stable surface.",
"After use, and after closure, the hypodermic needle holder 151 can be manually and forceably tipped to one side to disengage it cleanly from any surface.",
"Further, the hypodermic needle holder 151 may be supplied with an accompanying area of plastic base such as a credit card thickness of plastic to use as a further support, especially where there is no clean surface immediately employable for such purpose.",
"Such a support might have an area equivalent to the area of two or three wallet sized credit cards and may be pre-packaged with the hypodermic needle holder 151 as either a package add in or co-molded structure.",
"Where such a base is utilized, the base can be removed and discarded after the hypodermic needle holder 151 use has terminated and after the lid portion 153 is closed over the opening 15 .",
"The adhesive layer 187 , and hook arms 165 and 167 are but two types of structures for additional support of the hypodermic needle holder 151 , and other structures can be employed.",
"Additional support assists medical practitioners by eliminating the chances and the necessity to bring the practitioner's hands together which has a higher liklihood where the hypodermic needle holder 151 is manually held.",
"Even where manual holding is necessary, manual grasping can occur at the bottom end of the holder 151 , away from the opening 15 .",
"Although the invention has been derived with reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention.",
"Therefore, included within the patent warranted hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art."
] |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from U.S. Provisional Patent Application Serial No. 60/214,817, filed Jun. 29, 2000, which is hereby incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to the sputter deposition of material layers. More particularly, the present invention relates to methods and apparatus for depositing films that apply AC (e.g., radio frequency (RF)) power to a chamber coil and/or to a substrate support, or that apply power to a sputtering target.
BACKGROUND OF THE INVENTION
[0003] Manufacture of certain semiconductor devices requires a sputtering process in which a target is mounted in a sputtering chamber and bombarded with ions. The ion bombardment causes the target to emit molecules that are deposited on a substrate that is the subject of the sputtering process.
[0004] [0004]FIG. 1 is a schematic side elevational view of a conventional chamber 11 adapted to sputter deposit a layer of material such as aluminum nitride. The chamber 11 comprises a chamber enclosure having an enclosing wall 13 , and an insulating region 15 coupled to the enclosing wall 13 and adapted to support a sputtering target 19 . The chamber 11 is adapted to couple the sputtering target 19 to a source of varying power (e.g., a pulsed direct current power source that is pulsed by being repeatedly turned on and off). Specifically, a power supply line 21 couples the target 19 to a varying power source 23 as shown in FIG. 1. Conventionally the power supply line 21 may comprise a coaxial cable, a center portion of which supplies power to the target 19 , and an outer shield portion of which provides a ground line between the target 19 and the varying power supply 23 . The insulating region 15 prevents the varying power applied to the target 19 from being transmitted to the enclosing wall 13 .
[0005] A controller C is coupled to various chamber components via a plurality of controller wires 26 , and functions to control the chamber components coupled thereto.
[0006] The present inventors have discovered that power supplied from the varying power source 23 to the sputtering target 19 tends to couple to other chamber components, thereby causing undesirable effects (i.e., electrical noise). Among the possible effects of such noise are causing an erroneous high-voltage reading which may cause the controller C to terminate processing (i.e., triggering an emergency shutoff of controller C). Other undesirable effects or noise may include erroneous data readings on the monitor of the controller C, fluctuation or instability of the pointer on the monitor of controller C, etc.
[0007] Accordingly, the present inventors have recognized a need to address noise problems associated with a power source for a sputtering chamber.
SUMMARY OF THE INVENTION
[0008] To reduce the noise experienced by conventional chambers that apply AC (e.g., RF) power to a chamber coil and/or to a substrate support, or that apply pulsed DC power to a sputtering target, the inventive chamber comprises one or more of the following features:
[0009] a grounded shield plate coupled to a sputtering target (e.g., via an insulating member);
[0010] a ground line, separate from a power supply line (i.e., other than the shield portion of the power supply line) coupled to both the chamber's enclosure wall and to a varying power supply; and/or
[0011] one or more filters coupled in series between one or more chamber components and a controller C.
[0012] In one aspect the ground line is as short as possible, and the varying power supply is installed close to the inventive chamber so as to reduce the length of the power supply line, thereby minimizing detrimental capacitance and inductance that may occur therealong. The mechanism for grounding the shield plate may comprise a metal block which couples to both the shield plate and the chamber's enclosure wall via a plurality of springs. The one or more filters may be designed to reject the specific noise bandwidth (e.g., RF noise bandwidth) detected on the specific controller wire to which the filter is coupled.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] [0013]FIG. 1 is a schematic side elevational view of a conventional chamber 11 adapted to sputter deposit a layer of material;
[0014] [0014]FIG. 2 is a schematic side elevational view of an inventive chamber 111 ;
[0015] [0015]FIG. 3 is a schematic diagram of an exemplary filter 33 for filtering controller wires 401 a - d in accordance with the present invention; and
[0016] [0016]FIGS. 4A and 4B are diagrammatic side views of an exemplary inventive chamber 411 configured for aluminum nitride deposition, wherein a shutter disk is shown in a closed position (FIG. 4A) and in an open position (FIG. 4B).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] [0017]FIG. 2 is a schematic side elevational view of an inventive chamber 111 . The inventive chamber 111 comprises the same components as those described with reference to the conventional chamber 11 of FIG. 1. Accordingly, the components which are the same will be briefly enumerated, and only the aspects of the inventive chamber 111 that differ from the conventional chamber 11 will be described in detail.
[0018] Briefly, the chamber 11 includes a chamber enclosure having an enclosing wall 13 and an insulating region 15 adapted to support a sputtering target 19 . A power supply line 21 couples the target 19 to a varying power source 23 . A controller C is coupled to various chamber components via a plurality of controller wires 26 .
[0019] To reduce the noise experienced by the conventional chamber 11 , the inventive chamber 111 comprises one or more of the following features:
[0020] a shield plate 27 coupled to the insulating region 15 , and a grounding mechanism 29 coupled to the shield plate 27 and to the enclosing wall 13 so as to provide electrical grounding therebetween;
[0021] a ground line 31 , separate from the power supply line 21 (i.e., other than the shield portion of the power supply line 21 ) coupled to both the enclosing wall 13 and to the varying power supply 23 ; and/or
[0022] one or more filters 33 coupled to controller wires 26 in series between the one or more chamber components (see FIG. 4), and the controller C.
[0023] In one aspect the ground line 31 is as short as possible, and the varying power supply 23 is installed close to the inventive chamber 111 so as to reduce the length of the power supply line 21 , thereby minimizing detrimental capacitance and inductance that may occur therealong. The grounding mechanism 29 may comprise a metal block which couples to both the shield plate 27 and the enclosure wall 13 via a plurality of springs 35 . The one or more filters 33 may be designed to reject the specific noise bandwidth detected on the specific controller wire 26 to which the filter 33 is coupled. The filters 33 may be designed using a simulation tool in order to obtain a desired frequency response, and may be designed for differential mode filtering or for single mode filtering, as is known in the art.
[0024] [0024]FIG. 3 is a schematic diagram of an exemplary filter 33 for filtering controller wires 401 a - d in accordance with the present invention. With reference to FIG. 3, the filter 33 comprises channel circuitry 33 a and 33 b for filtering controller wires 401 a - d (e.g., a differential mode filter circuit comprising a plurality of capacitors and inductors configured as shown in FIG. 3). The specific capacitor and inductor values shown in FIG. 3 (e.g., 0.2 microFarad capacitors coupled between each controller wire 401 a - d and ground, 0.1 microFarad capacitors coupled between the controller wires 401 a - c , and 100 microHenry inductors coupled in series with each controller wire 401 a - d ) are selected to provide low-pass filtering for each controller wire 401 a - d with a cutoff frequency of about 50 kHz (e.g., so as to reject the 70 kHz or greater pulsed D.C. signal typically applied to a target during sputter deposition of dielectric layers such as aluminum nitride.)
[0025] [0025]FIGS. 4A and 4B are diagrammatic side views of an exemplary inventive chamber 411 configured for aluminum nitride deposition, wherein a shutter disk is shown in a closed position (FIG. 4A) and in an open position (FIG. 4B). With reference to FIGS. 4A and 4B, the deposition chamber 411 generally includes a chamber enclosure wall 413 having an inlet 414 coupled to first and second gas lines 415 a - b . The first and second gas lines 415 a - b are coupled to a processing gas source 417 a (e.g., nitrogen) and to a carrier gas source 417 b (e.g., argon), respectively, and an exhaust outlet 419 is coupled to an exhaust pump 421 . A substrate support 423 is disposed in the lower portion of the deposition chamber 411 , and a target 427 (e.g., an aluminum target for aluminum nitride deposition or a titanium target for titanium nitride deposition) is mounted to an upper surface of the deposition chamber 411 . An AC power supply 429 is operatively coupled to the substrate support 423 so that an AC power signal emitted from the AC power supply 429 will couple through the substrate support 423 to a substrate 431 (FIG. 4B) positioned thereon.
[0026] A clamp ring 433 is operatively coupled to the substrate support 423 so as to press the substrate 431 (FIG. 4B) uniformly against the substrate support 423 . A shutter assembly (not shown) is rotatably mounted within the deposition chamber 411 which selectively positions a shutter disk 435 between the target 427 and the substrate support 423 (i.e., placing the shutter disk 435 in a closed position) as shown in FIG. 4A. Thus, when the shutter disk 435 is in the closed position, deposition material is prevented from depositing on surfaces below the shutter disk 435 . Preferably the shutter disk 435 is positioned between the clamp ring 433 and the substrate support 423 when the shutter disk 435 is in the closed position (as shown in FIG. 4A).
[0027] The target 427 is electrically isolated from the chamber enclosure wall 413 by an insulation region 437 . Any sputtered particles, which accumulate on the insulation member 437 during deposition (described below), may cause an electrical short circuit between the chamber enclosure wall 413 and the target 427 (e.g., preventing the deposition chamber 411 from functioning). Therefore, a process kit part (e.g., a shield 439 ) may be positioned between the target 427 and the insulation region 437 to prevent sputtered particles from accumulating on the insulation region 437 .
[0028] The chamber enclosure wall 413 is preferably grounded so that a negative voltage potential may be selectively generated (e.g., pulsed ON or OFF) between the target 427 and the grounded enclosure wall 413 via a DC power supply 441 . A controller 443 is operatively coupled to the DC power supply 441 , to the gas lines 415 a , 415 b via first and second flow controllers 445 a , 445 b (e.g., first and second mass flow controllers) to the exhaust outlet 419 via a throttle valve 447 and to the AC power supply 429 . The controller may be programmed to pulse the DC power applied to the target at a radio frequency.
[0029] In operation, to deposit either aluminum nitride or titanium nitride within the deposition chamber 411 , nitrogen (e.g., a processing gas) and a carrier gas (typically a non-reactive species such as Argon) are supplied by the processing gas source 417 a and by the carrier gas source 417 b , and are flowed into the deposition chamber 411 through the gas lines 415 a - b , respectively, and through the inlet 414 at flow rates regulated by the controller 443 . The nitrogen flow rate is selected so that the nitrogen reacts with the target material forming a nitride layer (e.g., an aluminum nitride layer for an aluminum target or a titanium nitride layer for a titanium target) thereon. The controller 443 also regulates the pressure of the deposition chamber by throttling the rate at which gas is pumped through the exhaust outlet 419 (e.g., via the throttle valve 447 ). Accordingly, although a constant chamber pressure is maintained during deposition, a continuous supply of fresh processing gas is supplied to the deposition chamber 411 .
[0030] The D.C. power supply 441 (e.g., via a command from the controller 443 ) applies a negative voltage to the target 427 with respect to the chamber enclosure wall 413 so as to excite the processing gas/carrier gas within the chamber 411 into a plasma state (e.g., thereby generating a plasma within the chamber 411 ). Ions from the plasma (e.g., argon ions) bombard the target 427 , causing molecules of the nitrided target layer to sputter therefrom. The sputtered molecules travel along linear trajectories from the target 427 and deposit on the substrate 431 (FIG. 4B). The negative voltage applied to the target is turned ON and OFF at a radio frequency rate (e.g., about 70 kHZ), causing the target to be sputtered during power ON state, and allowing a fresh layer of aluminum nitride to form on the target during the power OFF state.
[0031] The use of the grounded shield plate 27 , the ground line 31 , and/or the one or more filters 33 , significantly reduce or eliminate the occurrence of noise in the inventive deposition chamber 411 . Specifically, with use of the inventive chamber, less current couples to chamber components, a higher percentage of the current is returned to the power supply (e.g., via the ground line, and via the grounded shield), and any remaining current may be filtered from the controller lines.
[0032] The foregoing description discloses only the preferred embodiments of the invention; modifications of the above disclosed apparatus and method which fall within the scope of the invention will be readily apparent to those of ordinary skill in the art. For instance, the invention is not limited to sputtering targets mounted on the top of a chamber; other mounting positions may be employed. Similarly, the AC power of frequencies other than radio frequency and the DC power pulsed at frequencies other than radio frequency may be applied to the target. Filters other than the exemplary circuits described herein may be employed, and any mechanism may be employed to ground the shield plate to the enclosure wall. The present invention also may be used within chambers that employ a coil (e.g., a high density plasma chamber) and/or an RF substrate support bias. For example, to deposit TiN or TaN, a chamber coil typically is employed within a sputtering chamber, the chamber coil is biased via a 2 MHz RF power signal and a substrate support within the chamber is biased with a 13.5 MHz RF signal. The present invention may be employed to reduce noise due to either RF power signal (e.g., by connecting the ground connection of any RF power supplies that are employed to the chamber enclosure wall of the chamber in a manner similar to the ground connection of the pulsed D.C. power supply 23 of FIG. 2).
[0033] Accordingly, while the present invention has been disclosed in connection with the preferred embodiments thereof, it should be understood that other embodiments may fall within the spirit and scope of the invention, as defined by the following claims. | A sputter deposition chamber may be fitted with measures to prevent or reduce electrical noise that might otherwise interfere with a controller for the sputter deposition chamber. A grounded shield plate may be coupled to an insulating member by which a sputtering target is mounted in the chamber. A ground line, separate from a power supply line, may be coupled to the chamber's enclosure wall and to a varying power supply. One or more filters may be coupled in series between chamber components and a controller associated with the chamber. | Condense the core contents of the given document. | [
"CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims priority from U.S. Provisional Patent Application Serial No. 60/214,817, filed Jun. 29, 2000, which is hereby incorporated by reference herein in its entirety.",
"FIELD OF THE INVENTION [0002] The present invention relates to the sputter deposition of material layers.",
"More particularly, the present invention relates to methods and apparatus for depositing films that apply AC (e.g., radio frequency (RF)) power to a chamber coil and/or to a substrate support, or that apply power to a sputtering target.",
"BACKGROUND OF THE INVENTION [0003] Manufacture of certain semiconductor devices requires a sputtering process in which a target is mounted in a sputtering chamber and bombarded with ions.",
"The ion bombardment causes the target to emit molecules that are deposited on a substrate that is the subject of the sputtering process.",
"[0004] [0004 ]FIG. 1 is a schematic side elevational view of a conventional chamber 11 adapted to sputter deposit a layer of material such as aluminum nitride.",
"The chamber 11 comprises a chamber enclosure having an enclosing wall 13 , and an insulating region 15 coupled to the enclosing wall 13 and adapted to support a sputtering target 19 .",
"The chamber 11 is adapted to couple the sputtering target 19 to a source of varying power (e.g., a pulsed direct current power source that is pulsed by being repeatedly turned on and off).",
"Specifically, a power supply line 21 couples the target 19 to a varying power source 23 as shown in FIG. 1. Conventionally the power supply line 21 may comprise a coaxial cable, a center portion of which supplies power to the target 19 , and an outer shield portion of which provides a ground line between the target 19 and the varying power supply 23 .",
"The insulating region 15 prevents the varying power applied to the target 19 from being transmitted to the enclosing wall 13 .",
"[0005] A controller C is coupled to various chamber components via a plurality of controller wires 26 , and functions to control the chamber components coupled thereto.",
"[0006] The present inventors have discovered that power supplied from the varying power source 23 to the sputtering target 19 tends to couple to other chamber components, thereby causing undesirable effects (i.e., electrical noise).",
"Among the possible effects of such noise are causing an erroneous high-voltage reading which may cause the controller C to terminate processing (i.e., triggering an emergency shutoff of controller C).",
"Other undesirable effects or noise may include erroneous data readings on the monitor of the controller C, fluctuation or instability of the pointer on the monitor of controller C, etc.",
"[0007] Accordingly, the present inventors have recognized a need to address noise problems associated with a power source for a sputtering chamber.",
"SUMMARY OF THE INVENTION [0008] To reduce the noise experienced by conventional chambers that apply AC (e.g., RF) power to a chamber coil and/or to a substrate support, or that apply pulsed DC power to a sputtering target, the inventive chamber comprises one or more of the following features: [0009] a grounded shield plate coupled to a sputtering target (e.g., via an insulating member);",
"[0010] a ground line, separate from a power supply line (i.e., other than the shield portion of the power supply line) coupled to both the chamber's enclosure wall and to a varying power supply;",
"and/or [0011] one or more filters coupled in series between one or more chamber components and a controller C. [0012] In one aspect the ground line is as short as possible, and the varying power supply is installed close to the inventive chamber so as to reduce the length of the power supply line, thereby minimizing detrimental capacitance and inductance that may occur therealong.",
"The mechanism for grounding the shield plate may comprise a metal block which couples to both the shield plate and the chamber's enclosure wall via a plurality of springs.",
"The one or more filters may be designed to reject the specific noise bandwidth (e.g., RF noise bandwidth) detected on the specific controller wire to which the filter is coupled.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0013] [0013 ]FIG. 1 is a schematic side elevational view of a conventional chamber 11 adapted to sputter deposit a layer of material;",
"[0014] [0014 ]FIG. 2 is a schematic side elevational view of an inventive chamber 111 ;",
"[0015] [0015 ]FIG. 3 is a schematic diagram of an exemplary filter 33 for filtering controller wires 401 a - d in accordance with the present invention;",
"and [0016] [0016 ]FIGS. 4A and 4B are diagrammatic side views of an exemplary inventive chamber 411 configured for aluminum nitride deposition, wherein a shutter disk is shown in a closed position (FIG.",
"4A) and in an open position (FIG.",
"4B).",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0017] [0017 ]FIG. 2 is a schematic side elevational view of an inventive chamber 111 .",
"The inventive chamber 111 comprises the same components as those described with reference to the conventional chamber 11 of FIG. 1. Accordingly, the components which are the same will be briefly enumerated, and only the aspects of the inventive chamber 111 that differ from the conventional chamber 11 will be described in detail.",
"[0018] Briefly, the chamber 11 includes a chamber enclosure having an enclosing wall 13 and an insulating region 15 adapted to support a sputtering target 19 .",
"A power supply line 21 couples the target 19 to a varying power source 23 .",
"A controller C is coupled to various chamber components via a plurality of controller wires 26 .",
"[0019] To reduce the noise experienced by the conventional chamber 11 , the inventive chamber 111 comprises one or more of the following features: [0020] a shield plate 27 coupled to the insulating region 15 , and a grounding mechanism 29 coupled to the shield plate 27 and to the enclosing wall 13 so as to provide electrical grounding therebetween;",
"[0021] a ground line 31 , separate from the power supply line 21 (i.e., other than the shield portion of the power supply line 21 ) coupled to both the enclosing wall 13 and to the varying power supply 23 ;",
"and/or [0022] one or more filters 33 coupled to controller wires 26 in series between the one or more chamber components (see FIG. 4), and the controller C. [0023] In one aspect the ground line 31 is as short as possible, and the varying power supply 23 is installed close to the inventive chamber 111 so as to reduce the length of the power supply line 21 , thereby minimizing detrimental capacitance and inductance that may occur therealong.",
"The grounding mechanism 29 may comprise a metal block which couples to both the shield plate 27 and the enclosure wall 13 via a plurality of springs 35 .",
"The one or more filters 33 may be designed to reject the specific noise bandwidth detected on the specific controller wire 26 to which the filter 33 is coupled.",
"The filters 33 may be designed using a simulation tool in order to obtain a desired frequency response, and may be designed for differential mode filtering or for single mode filtering, as is known in the art.",
"[0024] [0024 ]FIG. 3 is a schematic diagram of an exemplary filter 33 for filtering controller wires 401 a - d in accordance with the present invention.",
"With reference to FIG. 3, the filter 33 comprises channel circuitry 33 a and 33 b for filtering controller wires 401 a - d (e.g., a differential mode filter circuit comprising a plurality of capacitors and inductors configured as shown in FIG. 3).",
"The specific capacitor and inductor values shown in FIG. 3 (e.g., 0.2 microFarad capacitors coupled between each controller wire 401 a - d and ground, 0.1 microFarad capacitors coupled between the controller wires 401 a - c , and 100 microHenry inductors coupled in series with each controller wire 401 a - d ) are selected to provide low-pass filtering for each controller wire 401 a - d with a cutoff frequency of about 50 kHz (e.g., so as to reject the 70 kHz or greater pulsed D.C. signal typically applied to a target during sputter deposition of dielectric layers such as aluminum nitride.) [0025] [0025 ]FIGS. 4A and 4B are diagrammatic side views of an exemplary inventive chamber 411 configured for aluminum nitride deposition, wherein a shutter disk is shown in a closed position (FIG.",
"4A) and in an open position (FIG.",
"4B).",
"With reference to FIGS. 4A and 4B, the deposition chamber 411 generally includes a chamber enclosure wall 413 having an inlet 414 coupled to first and second gas lines 415 a - b .",
"The first and second gas lines 415 a - b are coupled to a processing gas source 417 a (e.g., nitrogen) and to a carrier gas source 417 b (e.g., argon), respectively, and an exhaust outlet 419 is coupled to an exhaust pump 421 .",
"A substrate support 423 is disposed in the lower portion of the deposition chamber 411 , and a target 427 (e.g., an aluminum target for aluminum nitride deposition or a titanium target for titanium nitride deposition) is mounted to an upper surface of the deposition chamber 411 .",
"An AC power supply 429 is operatively coupled to the substrate support 423 so that an AC power signal emitted from the AC power supply 429 will couple through the substrate support 423 to a substrate 431 (FIG.",
"4B) positioned thereon.",
"[0026] A clamp ring 433 is operatively coupled to the substrate support 423 so as to press the substrate 431 (FIG.",
"4B) uniformly against the substrate support 423 .",
"A shutter assembly (not shown) is rotatably mounted within the deposition chamber 411 which selectively positions a shutter disk 435 between the target 427 and the substrate support 423 (i.e., placing the shutter disk 435 in a closed position) as shown in FIG. 4A.",
"Thus, when the shutter disk 435 is in the closed position, deposition material is prevented from depositing on surfaces below the shutter disk 435 .",
"Preferably the shutter disk 435 is positioned between the clamp ring 433 and the substrate support 423 when the shutter disk 435 is in the closed position (as shown in FIG. 4A).",
"[0027] The target 427 is electrically isolated from the chamber enclosure wall 413 by an insulation region 437 .",
"Any sputtered particles, which accumulate on the insulation member 437 during deposition (described below), may cause an electrical short circuit between the chamber enclosure wall 413 and the target 427 (e.g., preventing the deposition chamber 411 from functioning).",
"Therefore, a process kit part (e.g., a shield 439 ) may be positioned between the target 427 and the insulation region 437 to prevent sputtered particles from accumulating on the insulation region 437 .",
"[0028] The chamber enclosure wall 413 is preferably grounded so that a negative voltage potential may be selectively generated (e.g., pulsed ON or OFF) between the target 427 and the grounded enclosure wall 413 via a DC power supply 441 .",
"A controller 443 is operatively coupled to the DC power supply 441 , to the gas lines 415 a , 415 b via first and second flow controllers 445 a , 445 b (e.g., first and second mass flow controllers) to the exhaust outlet 419 via a throttle valve 447 and to the AC power supply 429 .",
"The controller may be programmed to pulse the DC power applied to the target at a radio frequency.",
"[0029] In operation, to deposit either aluminum nitride or titanium nitride within the deposition chamber 411 , nitrogen (e.g., a processing gas) and a carrier gas (typically a non-reactive species such as Argon) are supplied by the processing gas source 417 a and by the carrier gas source 417 b , and are flowed into the deposition chamber 411 through the gas lines 415 a - b , respectively, and through the inlet 414 at flow rates regulated by the controller 443 .",
"The nitrogen flow rate is selected so that the nitrogen reacts with the target material forming a nitride layer (e.g., an aluminum nitride layer for an aluminum target or a titanium nitride layer for a titanium target) thereon.",
"The controller 443 also regulates the pressure of the deposition chamber by throttling the rate at which gas is pumped through the exhaust outlet 419 (e.g., via the throttle valve 447 ).",
"Accordingly, although a constant chamber pressure is maintained during deposition, a continuous supply of fresh processing gas is supplied to the deposition chamber 411 .",
"[0030] The D.C. power supply 441 (e.g., via a command from the controller 443 ) applies a negative voltage to the target 427 with respect to the chamber enclosure wall 413 so as to excite the processing gas/carrier gas within the chamber 411 into a plasma state (e.g., thereby generating a plasma within the chamber 411 ).",
"Ions from the plasma (e.g., argon ions) bombard the target 427 , causing molecules of the nitrided target layer to sputter therefrom.",
"The sputtered molecules travel along linear trajectories from the target 427 and deposit on the substrate 431 (FIG.",
"4B).",
"The negative voltage applied to the target is turned ON and OFF at a radio frequency rate (e.g., about 70 kHZ), causing the target to be sputtered during power ON state, and allowing a fresh layer of aluminum nitride to form on the target during the power OFF state.",
"[0031] The use of the grounded shield plate 27 , the ground line 31 , and/or the one or more filters 33 , significantly reduce or eliminate the occurrence of noise in the inventive deposition chamber 411 .",
"Specifically, with use of the inventive chamber, less current couples to chamber components, a higher percentage of the current is returned to the power supply (e.g., via the ground line, and via the grounded shield), and any remaining current may be filtered from the controller lines.",
"[0032] The foregoing description discloses only the preferred embodiments of the invention;",
"modifications of the above disclosed apparatus and method which fall within the scope of the invention will be readily apparent to those of ordinary skill in the art.",
"For instance, the invention is not limited to sputtering targets mounted on the top of a chamber;",
"other mounting positions may be employed.",
"Similarly, the AC power of frequencies other than radio frequency and the DC power pulsed at frequencies other than radio frequency may be applied to the target.",
"Filters other than the exemplary circuits described herein may be employed, and any mechanism may be employed to ground the shield plate to the enclosure wall.",
"The present invention also may be used within chambers that employ a coil (e.g., a high density plasma chamber) and/or an RF substrate support bias.",
"For example, to deposit TiN or TaN, a chamber coil typically is employed within a sputtering chamber, the chamber coil is biased via a 2 MHz RF power signal and a substrate support within the chamber is biased with a 13.5 MHz RF signal.",
"The present invention may be employed to reduce noise due to either RF power signal (e.g., by connecting the ground connection of any RF power supplies that are employed to the chamber enclosure wall of the chamber in a manner similar to the ground connection of the pulsed D.C. power supply 23 of FIG. 2).",
"[0033] Accordingly, while the present invention has been disclosed in connection with the preferred embodiments thereof, it should be understood that other embodiments may fall within the spirit and scope of the invention, as defined by the following claims."
] |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an apparatus and method for managing air conditioning of a data center, more specifically, an air conditioning management apparatus and management method of the same for increasing the Power Usage Effect (PUE) by utilizing the sensing information inside and outside a data center.
[0003] 2. Background of the Invention
[0004] Until recently, it was not many interested in energy cost which is used to IT systems. However, depending on the increase of electricity prices and power consumption, energy costs is becoming one of important factors when making decisions about the design and data center position.
[0005] As a result of the analysis of energy usage in the data center, it is analyzed that IT system occupies 50% of the total data center electricity consumption. It shows that a system next to the electricity consumption of IT systems is a cooling system, which occupies 37% of total electricity consumption of data center.
[0006] Depending on the recent explosive usage amount of computer, the size of the data center has been enlarged. Now, although it is depending on the size of the data center, the electricity consumption amount of domestic and overseas data center is equivalent to the energy consumption used in small and medium-sized cities. Accordingly, when designing a data center from 2000, by the design of efficient server room cooling and air conditioning management, data center design of low power consumption concept is being carried out.
[0007] In order to optimize the cooling environment of the data center to remove the heat as much as possible from the device with the minimum energy, to ensure efficient ventilation routes is important. In order to optimize ventilation routes (flow of air) in the data center, rack configuration and air conditioning management system placement must be optimized. Today, in most data centers, the rack is placed so that the cooled wind flow from the front of the rack and the hot air is exhausted back. Speaking once again, the hot air region (Hot zone) and cold air region (Cold zone) are formed on the peripheral side of the rack.
[0008] Therefore, after equipping with an air conditioning management facility so that hot air and hot air are not mixed each other, it is needed that hot air is exhausted outside the data center and cold outer air is flowed into the data center by an efficient and less energy.
PRIOR ART
[Patent Document] KR 10-1134468
[Patent Document] KR 10-1308969
BRIEF SUMMARY OF THE INVENTION
[0009] The present invention controls air conditioning of a data center, thereby maximizing energy efficiency (power efficiency) by controlling a blower and a filter using a sensor.
[0010] An air conditioning management apparatus of a data center according to an embodiment of the present invention includes a detector for detecting a temperature of an air exhausted from server racks, detecting the degree of contamination of a filter for purifying an outside air, and outputting a sensing information for it; a power supply for supplying a operation power to a exhaust blower for exhausting an inside air of the data center to an outside and an air supply blower for supplying the outside air to the data center; and a controller for controlling operations of the exhaust blower and the air supply blower by controlling the power supply depending on the sensing information, and determining and notifying a replacement time of the filter.
[0011] Preferably, rear parts of the server racks are arranged to face each other, spacing a distance apart, and forms a hot zone that causes a hot air emitted from the server racks to be collected in the rear part, the detector detects a temperature of the hot zone.
[0012] An air conditioning management method of the data center according to an embodiment of the present invention is an air conditioning management method of an air conditioning management apparatus of data center which rear parts of server racks are arranged to face each other, spacing a distance apart, and a hot zone that causes a hot air emitted from the server racks to be collected in the rear part is formed, the method comprising the steps of: detecting a temperature of the hot zone and the degree of contamination of a filter for purifying a outside air; exhausting the air of the hot zone to outside by operating an exhaust blower and supplying the outside air through the filter to the data center by operating an air supply blower; and outputting a message notifying a replacement of the filter, If the degree of contamination of the filter is more than a reference value or equal to the reference value.
Effect of the Invention
[0013] The present invention can controls air conditioning of a data center while maximizing energy efficiency, by controlling exhaust and intake blowers using a sensor and automatically checking the replacement time of the filter for purifying outside air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a diagram showing a rack placement and a installation view of a closed exhaust diffuser in the data center according to an embodiment of the present invention.
[0015] FIG. 2 is a configuration diagram showing the entire configuration of an air conditioning management system in the data center according to an embodiment of the present invention.
[0016] FIG. 3 is a diagram showing in more detail the constitution of the air conditioning management apparatus according to an embodiment of the present invention.
[0017] FIG. 4 is a flowchart illustrating a method for managing the exhaust operation in the air conditioning management method according to an embodiment of the present invention.
[0018] FIG. 5 is a flowchart illustrating a method for managing the replacement of an air supply filter in the air conditioning management method according to an embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0019] Hereinafter, referring to drawings attached, preferred embodiments of the present invention will be described in detail. Prior to this, words and terms used in this specification and claims must not be construed as being limited in an usual or dictionary meaning, and must be understood as the meaning and concept meeting the technical concept of the present invention based on the principle that a inventor can properly defines the concept of term to explain the invention with the best way. Thus, since embodiments described herein and constitutions shown in drawings are just preferable embodiments and not represent all technical concept of the present invention, at the time of the filing of this application, it must be understood that there are various equivalents and modifications which can replace them.
[0020] FIG. 1 is a diagram showing a rack placement and a installation view of a closed exhaust diffuser in the data center according to an embodiment of the present invention.
[0021] A plurality of Server racks ( 10 ), parts heat is generated, in other words, rear of the rack is spaced distance apart, are arranged in two rows so as to face each other, and an access door ( 50 ) is formed between the server racks of the outermost both of the arranged server racks ( 10 ). The access door ( 50 ) serve as dividing the rear space of server racks ( 10 ) into the space for confining hot air emitted from the server rack ( 10 ) (hereinafter, “Hot Zone”), and is also used as doorway for maintenance of the server.
[0022] On the top of hot zone, a pyramid diffuser ( 20 ), a exhaust diffuser ( 30 ) and a exhaust duct ( 40 ) are formed, and hot air confined in the hot zone is exhausted to the outside of the data center. The pyramid diffuser ( 20 ) and the access door ( 50 ) is able to be made of a transparent material so that the illumination of the data center can be transmitted to the hot zone. On the front floor of the rack server ( 10 ), an air flow panel ( 60 ) is installed. The outside air for cooling the inside of the data center is introduced into the data center through the air flow panel ( 60 ).
[0023] FIG. 2 is a configuration diagram showing the entire configuration of an air conditioning management system in the data center according to an embodiment of the present invention.
[0024] In the data center, there are a plurality of arrangement of the server racks ( 10 ) shown in FIG. 1 , and on the top of each server rack arrangement, the pyramid diffuser ( 20 _ 1 , 20 _ 2 ) the exhaust diffuser ( 30 _ 1 , 30 _ 2 ) and the exhaust duct ( 40 _ 1 , 40 _ 2 ) are installed. In other words, the hot air confined in each the hot zone is exhausted via the exhaust diffuser ( 30 _ 1 , 30 _ 2 ) through the exhaust duct ( 40 _ 1 , 40 _ 2 ) to the outside of the data center by pressure of an exhaust blower ( 80 _ 1 , 80 _ 2 ).
[0025] In each hot zone, a temperature sensor ( 120 _ 1 , 120 _ 2 ) to measure the temperature of the hot zone is installed. The temperature information for each hot zone measured from the temperature sensor ( 120 _ 1 , 120 _ 2 ) is transmitted to a control device ( 130 ). The control device ( 130 ) control exhausting the hot air in the hot zone into the outside of the data center by controlling operating speed (blowing speed) of each exhaust blower ( 80 _ 1 , 80 _ 2 ) according to the temperature information of each hot zone.
[0026] The air flow panel (Air flow Panel) ( 60 ) is connected to an air supply duct ( 70 _ 1 , 70 _ 2 ) installed at the bottom of the data center. Each air supply duct ( 70 _ 1 , 70 _ 2 ) is connected to an air supply blower ( 90 _ 1 , 90 _ 2 ), the air supply blower ( 90 _ 1 , 90 _ 2 ) is connect to a filter box ( 100 ). In other words, the outside air for cooling the inside of the data center is flowed through the filter box ( 100 ) by the pressure of the air supply blower ( 90 _ 1 , 90 _ 2 ) and via air supply duct ( 70 _ 1 , 70 _ 2 ), supplied to the inside of the data center.
[0027] The filter box ( 100 ) includes a filter ( 110 _ 1 ) to purify the outside air and an infrared sensor ( 110 _ 2 ) to detect the degree of contamination of the filter ( 110 _ 1 ). At this time, the filter ( 110 _ 1 ) includes a HEPA (HEPA: High Efficiency Particulate Air) filter. The infrared sensor ( 110 _ 2 ) detects color index (degree of monochrome) of the filter ( 110 _ 1 ). For example, if a lot of dust is stuck to the filter ( 110 _ 1 ), the color of the filter ( 110 _ 1 ) is changed to black color, and since the light projection ratio become low, the infrared sensor ( 110 _ 2 ) can detects the degree of contamination by measuring the light projection ratio. The infrared sensor ( 110 - 2 ) transfers the detected results to the control device ( 130 ).
[0028] The controller ( 130 ) outputs the signal (message) to inform the operator of filter replacement as long as the contamination state of the filter ( 110 _ 1 ) is more than the reference value. In this time, the control device ( 130 ) is able to determine the contamination level of the filter by using the average value after having received multiple times signals from infrared sensor ( 110 _ 2 ).
[0029] FIG. 3 is a diagram showing in more detail the constitution of the air conditioning management apparatus according to an embodiment of the present invention.
[0030] The air conditioning management apparatus includes a detector ( 310 ), a power supply ( 320 ) and a controller ( 330 ).
[0031] The detector ( 310 ) detects the temperature of the hot zone in the data center, detects degree of contamination of the filter ( 110 _ 1 ) installed in the filter box ( 100 ), and then transfer the detected sensing information to the controller ( 330 ). This detector ( 310 ) may includes a temperature sensor ( 120 _ 1 , 120 _ 2 ) installed on the hot zone in the data center, a infrared sensor ( 110 _ 2 ) for detecting degree of contamination installed in the filter box ( 100 ), and a microcontroller ( 312 ) for processing the signal sensed from the temperature sensor ( 120 _ 1 , 120 _ 2 ) and the infrared sensor ( 110 _ 2 ) and transferring the sensing information to a main controller ( 332 ) of the controller ( 330 ).
[0032] A power supply ( 320 ) selectively supplies the operating power to the exhaust blower ( 80 _ 1 , 80 _ 2 ) and air supply blower ( 90 _ 1 , 90 _ 2 ) depending on the control signal from the controller ( 300 ). The power supply ( 320 ) is connected to the exhaust blower ( 80 _ 1 , 80 _ 2 ) and air supply blower ( 90 _ 1 , 90 _ 2 ), and includes magnets that are on or off depending on the control signal of the main controller ( 332 ) of the controller ( 330 ) and a block switch ( 322 ) that allows the user to manually block the power at the time of the malfunction of the magnet.
[0033] The controller ( 330 ) controls the operation of the exhaust blower ( 80 _ 1 , 80 _ 2 ) and air supply blower ( 90 _ 1 , 90 _ 2 ) by controlling the operation of the power supply ( 320 ) depend on the sensing information from the detector ( 310 ). That is, the main controller ( 332 ) of the controller ( 330 ) controls whether the operation power is supplied to the exhaust blower ( 80 _ 1 , 80 _ 2 ) and air supply blower ( 90 _ 1 , 90 _ 2 ) connected to magnets (Magnet 1 , Magnet 2 ) or not, by selectively turning on/off the magnets (Magnet 1 , Magnet 2 ) of the power supply ( 320 ). And, the main controller ( 332 ) may controls the blowing speed of the exhaust blower ( 80 _ 1 , 80 _ 2 ) and the air supply blower ( 90 _ 1 , 90 _ 2 ) by controlling the power amount supplied to the exhaust blower ( 80 _ 1 , 80 _ 2 ) and the air supply blower ( 90 _ 1 , 90 _ 2 ) through the magnets (Magnet 1 , Magnet 2 ) when the magnets (Magnet 1 , Magnet 2 ) is on state. At this time, the main controller ( 332 ) eliminates a noise generated at the time of the on/off operation of the magnets (Magnet 1 , Magnet 2 ) using relays (Relay 1 , Relay 2 ). Also, the main controller ( 332 ) determines the replacement necessity (replacement time) of the filter ( 110 _ 1 ) in the filter box ( 100 ) depending on the sensing information from the microcontroller ( 312 ), and may display the message requesting the replacement of the filter on display unit ( 334 ) if it is determined that the replacement is needed. In addition, the main controller ( 332 ) generates the control signal turning off the magnets of the power supply ( 320 ) and transmits the signal to the power supply ( 320 ), if the blocking signal is received from the block switch ( 322 ) of the power supply ( 320 ).
[0034] FIG. 4 is a flowchart illustrating a method for managing the exhaust operation in the air conditioning management method according to an embodiment of the present invention.
[0035] The exhaust blower ( 81 _ 1 , 80 _ 2 ) for exhausting the hot air of the hot zone maintains a state that the power supply is usually turned off (step 410 ).
[0036] At this time, the micro controller ( 312 ) periodically checks the temperature of each hot zone using the temperature sensor ( 120 _ 1 , 120 _ 2 ) and transfers the sensing information from the temperature sensor ( 120 _ 1 , 120 _ 2 ) to the main controller ( 332 )
[0037] The main controller ( 332 ) compares the temperature of each hot zone with the preset reference temperature depending on the temperature information received from the micro controller ( 312 ) (step 420 )
[0038] At this time, if the temperature of a specific hot zone is more than the reference temperature, main controller ( 332 ) supplies the operation power to the exhaust blower (for example, 80_ 1 ) and the air supply blower (for example, 90_ 1 ) corresponding to the hot zone which the temperature is high by turning on the corresponding magnet (for example, Magnet 1 ) (step 430 ).
[0039] According to the supply of the operation power, if the exhaust blower ( 80 _ 1 ) and the air supply blower ( 90 _ 1 ) operate, the hot air of the corresponding hot zone is exhausted via the exhaust diffuser ( 30 _ 1 ) through the exhaust duct ( 40 _ 1 ) to the outside of the data center. And, by the pressure of the air supply blower ( 90 _ 1 ), the outside air is supplied to the inside of the data center through the filter ( 100 _ 1 ), the air supply duct ( 71 _ 1 ) and the air flow panel ( 60 _ 1 ).
[0040] If the temperature of all hot zone is more than the reference temperature, the main controller ( 332 ) operates both the exhaust blower ( 80 _ 1 , 80 _ 2 ) and the air supply blower ( 90 _ 1 , 90 _ 2 ) by turning on all magnets (Magnet 1 , Magnet 2 ), thereby supplying the outside air to the inside of the data center simultaneously while exhausting the hot air of all hot zones. At this time, the main controller ( 332 ) may detects the temperature of each hot zone in detail by subdividing the reference temperature, that is, using a plurality of temperatures which are different from each other. Hereby, the main controller ( 332 ) may independently controls the blowing speed of each of the exhaust blower ( 80 _ 1 , 80 _ 2 ) and the air supply blower ( 90 _ 1 , 90 _ 2 ) by individually controlling the each power amount supplied to the exhaust blower ( 80 _ 1 , 80 _ 2 ) and the air supply blower ( 90 _ 1 , 90 _ 2 ).
[0041] While the exhaust blower ( 80 _ 1 ) and the air supply blower ( 90 _ 1 ) operate, by continuously checking the temperature of the corresponding hot zone by detector ( 310 ), the main controller ( 332 ) indentifies whether the temperature of the hot zone is lower than the reference temperature again (step 440 ).
[0042] If the temperature of the hot zone is lower than the reference temperature by exhausting the hot air to the outside and supplying the outside air, the main controller ( 332 ) blocks the power supply supplied to the exhaust blower ( 80 _ 1 ) and the air supply blower ( 90 _ 1 ) by turning off the magnet (Magnet 1 ).
[0043] The operations of the above described steps 410 through 440 are repeatedly preformed until a different manipulation (instruction) by an operator.
[0044] FIG. 5 is a flowchart illustrating a method for managing the replacement of an air supply filter in the air conditioning management method according to an embodiment of the present invention.
[0045] A infrared sensor ( 110 _ 2 ) periodically irradiates a filter ( 110 _ 1 ) with infrared rays, and then detects the reflected light amount, and transmits the results to a micro controller ( 312 ). The micro controller ( 312 ) processes the sensing signal from a infrared sensor ( 110 _ 2 ) and measures a color index for the filter ( 110 _ 1 ) (step 510 ).
[0046] The micro controller ( 312 ) transmits the sensing information to the main controller ( 332 ) of the controller ( 330 ).
[0047] The main controller ( 332 ) determines whether the color index of the sensing information received from micro controller ( 312 ) is more than the preset reference value (step 520 ).
[0048] In these comparisons, after several sensing multiple color indexes of the filter ( 110 _ 1 ), the average value is can be compared with the reference value.
[0049] If the sensed color index is more than the reference value, the main controller ( 332 ) displays the message requesting the replacement of the filter on display unit ( 334 ) (step 530 ).
[0050] The above described embodiments of the present invention are for the purpose of illustration, it will be understood by those skilled in the art that various modifications, changes, replacements and addition may be made therein with departing from the spirit and scope of the appended claims, and these modifications and changes are said to belong to the scope of the following claims.
DESCRIPTION OF THE REFERENCE NUMERAL
[0051]
[0000]
10: server rack
20_1, 20_2: pyramid diffuser
30, 30_1, 30_2: exhaust diffuser
40, 40_1, 40_2: exhaust duct
50: access door
60: air flow panel
70_1, 70_2: air supply duct
80_1, 80_2: exhaust blower
90_1, 90_2: air supply blower
100: filter box
110_1: filter
110_2: infrared sensor
120_1, 120_2: temperature sensor
130: control device
310: detector
312: micro controllers
320: power supply
322: block switch
330: The controller
332: main controller
334: the display unit | An embodiment of the present invention relates to an air conditioning management apparatus which can increase the Power Usage Effect (PUE) by utilizing the sensing information inside and outside a data center, and includes a sensor for detecting a temperature of an air exhausted from server racks, detecting the degree of contamination of a filter for purifying an outside air, and outputting a sensing information for it; a power supply for supplying a operation power to a exhaust blower for exhausting an inside air of the data center to an outside and an air supply blower for supplying the outside air to the data center; and a controller for controlling operations of the exhaust blower and the air supply blower by controlling the power supply depending on the sensing information, and determining and notifying a replacement time of the filter. | Briefly summarize the main idea's components and working principles as described in the context. | [
"BACKGROUND OF THE INVENTION [0001] 1.",
"Field of the Invention [0002] The present invention relates to an apparatus and method for managing air conditioning of a data center, more specifically, an air conditioning management apparatus and management method of the same for increasing the Power Usage Effect (PUE) by utilizing the sensing information inside and outside a data center.",
"[0003] 2.",
"Background of the Invention [0004] Until recently, it was not many interested in energy cost which is used to IT systems.",
"However, depending on the increase of electricity prices and power consumption, energy costs is becoming one of important factors when making decisions about the design and data center position.",
"[0005] As a result of the analysis of energy usage in the data center, it is analyzed that IT system occupies 50% of the total data center electricity consumption.",
"It shows that a system next to the electricity consumption of IT systems is a cooling system, which occupies 37% of total electricity consumption of data center.",
"[0006] Depending on the recent explosive usage amount of computer, the size of the data center has been enlarged.",
"Now, although it is depending on the size of the data center, the electricity consumption amount of domestic and overseas data center is equivalent to the energy consumption used in small and medium-sized cities.",
"Accordingly, when designing a data center from 2000, by the design of efficient server room cooling and air conditioning management, data center design of low power consumption concept is being carried out.",
"[0007] In order to optimize the cooling environment of the data center to remove the heat as much as possible from the device with the minimum energy, to ensure efficient ventilation routes is important.",
"In order to optimize ventilation routes (flow of air) in the data center, rack configuration and air conditioning management system placement must be optimized.",
"Today, in most data centers, the rack is placed so that the cooled wind flow from the front of the rack and the hot air is exhausted back.",
"Speaking once again, the hot air region (Hot zone) and cold air region (Cold zone) are formed on the peripheral side of the rack.",
"[0008] Therefore, after equipping with an air conditioning management facility so that hot air and hot air are not mixed each other, it is needed that hot air is exhausted outside the data center and cold outer air is flowed into the data center by an efficient and less energy.",
"PRIOR ART [Patent Document] KR 10-1134468 [Patent Document] KR 10-1308969 BRIEF SUMMARY OF THE INVENTION [0009] The present invention controls air conditioning of a data center, thereby maximizing energy efficiency (power efficiency) by controlling a blower and a filter using a sensor.",
"[0010] An air conditioning management apparatus of a data center according to an embodiment of the present invention includes a detector for detecting a temperature of an air exhausted from server racks, detecting the degree of contamination of a filter for purifying an outside air, and outputting a sensing information for it;",
"a power supply for supplying a operation power to a exhaust blower for exhausting an inside air of the data center to an outside and an air supply blower for supplying the outside air to the data center;",
"and a controller for controlling operations of the exhaust blower and the air supply blower by controlling the power supply depending on the sensing information, and determining and notifying a replacement time of the filter.",
"[0011] Preferably, rear parts of the server racks are arranged to face each other, spacing a distance apart, and forms a hot zone that causes a hot air emitted from the server racks to be collected in the rear part, the detector detects a temperature of the hot zone.",
"[0012] An air conditioning management method of the data center according to an embodiment of the present invention is an air conditioning management method of an air conditioning management apparatus of data center which rear parts of server racks are arranged to face each other, spacing a distance apart, and a hot zone that causes a hot air emitted from the server racks to be collected in the rear part is formed, the method comprising the steps of: detecting a temperature of the hot zone and the degree of contamination of a filter for purifying a outside air;",
"exhausting the air of the hot zone to outside by operating an exhaust blower and supplying the outside air through the filter to the data center by operating an air supply blower;",
"and outputting a message notifying a replacement of the filter, If the degree of contamination of the filter is more than a reference value or equal to the reference value.",
"Effect of the Invention [0013] The present invention can controls air conditioning of a data center while maximizing energy efficiency, by controlling exhaust and intake blowers using a sensor and automatically checking the replacement time of the filter for purifying outside air.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 is a diagram showing a rack placement and a installation view of a closed exhaust diffuser in the data center according to an embodiment of the present invention.",
"[0015] FIG. 2 is a configuration diagram showing the entire configuration of an air conditioning management system in the data center according to an embodiment of the present invention.",
"[0016] FIG. 3 is a diagram showing in more detail the constitution of the air conditioning management apparatus according to an embodiment of the present invention.",
"[0017] FIG. 4 is a flowchart illustrating a method for managing the exhaust operation in the air conditioning management method according to an embodiment of the present invention.",
"[0018] FIG. 5 is a flowchart illustrating a method for managing the replacement of an air supply filter in the air conditioning management method according to an embodiment of the present invention.",
"DESCRIPTION OF EMBODIMENTS [0019] Hereinafter, referring to drawings attached, preferred embodiments of the present invention will be described in detail.",
"Prior to this, words and terms used in this specification and claims must not be construed as being limited in an usual or dictionary meaning, and must be understood as the meaning and concept meeting the technical concept of the present invention based on the principle that a inventor can properly defines the concept of term to explain the invention with the best way.",
"Thus, since embodiments described herein and constitutions shown in drawings are just preferable embodiments and not represent all technical concept of the present invention, at the time of the filing of this application, it must be understood that there are various equivalents and modifications which can replace them.",
"[0020] FIG. 1 is a diagram showing a rack placement and a installation view of a closed exhaust diffuser in the data center according to an embodiment of the present invention.",
"[0021] A plurality of Server racks ( 10 ), parts heat is generated, in other words, rear of the rack is spaced distance apart, are arranged in two rows so as to face each other, and an access door ( 50 ) is formed between the server racks of the outermost both of the arranged server racks ( 10 ).",
"The access door ( 50 ) serve as dividing the rear space of server racks ( 10 ) into the space for confining hot air emitted from the server rack ( 10 ) (hereinafter, “Hot Zone”), and is also used as doorway for maintenance of the server.",
"[0022] On the top of hot zone, a pyramid diffuser ( 20 ), a exhaust diffuser ( 30 ) and a exhaust duct ( 40 ) are formed, and hot air confined in the hot zone is exhausted to the outside of the data center.",
"The pyramid diffuser ( 20 ) and the access door ( 50 ) is able to be made of a transparent material so that the illumination of the data center can be transmitted to the hot zone.",
"On the front floor of the rack server ( 10 ), an air flow panel ( 60 ) is installed.",
"The outside air for cooling the inside of the data center is introduced into the data center through the air flow panel ( 60 ).",
"[0023] FIG. 2 is a configuration diagram showing the entire configuration of an air conditioning management system in the data center according to an embodiment of the present invention.",
"[0024] In the data center, there are a plurality of arrangement of the server racks ( 10 ) shown in FIG. 1 , and on the top of each server rack arrangement, the pyramid diffuser ( 20 _ 1 , 20 _ 2 ) the exhaust diffuser ( 30 _ 1 , 30 _ 2 ) and the exhaust duct ( 40 _ 1 , 40 _ 2 ) are installed.",
"In other words, the hot air confined in each the hot zone is exhausted via the exhaust diffuser ( 30 _ 1 , 30 _ 2 ) through the exhaust duct ( 40 _ 1 , 40 _ 2 ) to the outside of the data center by pressure of an exhaust blower ( 80 _ 1 , 80 _ 2 ).",
"[0025] In each hot zone, a temperature sensor ( 120 _ 1 , 120 _ 2 ) to measure the temperature of the hot zone is installed.",
"The temperature information for each hot zone measured from the temperature sensor ( 120 _ 1 , 120 _ 2 ) is transmitted to a control device ( 130 ).",
"The control device ( 130 ) control exhausting the hot air in the hot zone into the outside of the data center by controlling operating speed (blowing speed) of each exhaust blower ( 80 _ 1 , 80 _ 2 ) according to the temperature information of each hot zone.",
"[0026] The air flow panel (Air flow Panel) ( 60 ) is connected to an air supply duct ( 70 _ 1 , 70 _ 2 ) installed at the bottom of the data center.",
"Each air supply duct ( 70 _ 1 , 70 _ 2 ) is connected to an air supply blower ( 90 _ 1 , 90 _ 2 ), the air supply blower ( 90 _ 1 , 90 _ 2 ) is connect to a filter box ( 100 ).",
"In other words, the outside air for cooling the inside of the data center is flowed through the filter box ( 100 ) by the pressure of the air supply blower ( 90 _ 1 , 90 _ 2 ) and via air supply duct ( 70 _ 1 , 70 _ 2 ), supplied to the inside of the data center.",
"[0027] The filter box ( 100 ) includes a filter ( 110 _ 1 ) to purify the outside air and an infrared sensor ( 110 _ 2 ) to detect the degree of contamination of the filter ( 110 _ 1 ).",
"At this time, the filter ( 110 _ 1 ) includes a HEPA (HEPA: High Efficiency Particulate Air) filter.",
"The infrared sensor ( 110 _ 2 ) detects color index (degree of monochrome) of the filter ( 110 _ 1 ).",
"For example, if a lot of dust is stuck to the filter ( 110 _ 1 ), the color of the filter ( 110 _ 1 ) is changed to black color, and since the light projection ratio become low, the infrared sensor ( 110 _ 2 ) can detects the degree of contamination by measuring the light projection ratio.",
"The infrared sensor ( 110 - 2 ) transfers the detected results to the control device ( 130 ).",
"[0028] The controller ( 130 ) outputs the signal (message) to inform the operator of filter replacement as long as the contamination state of the filter ( 110 _ 1 ) is more than the reference value.",
"In this time, the control device ( 130 ) is able to determine the contamination level of the filter by using the average value after having received multiple times signals from infrared sensor ( 110 _ 2 ).",
"[0029] FIG. 3 is a diagram showing in more detail the constitution of the air conditioning management apparatus according to an embodiment of the present invention.",
"[0030] The air conditioning management apparatus includes a detector ( 310 ), a power supply ( 320 ) and a controller ( 330 ).",
"[0031] The detector ( 310 ) detects the temperature of the hot zone in the data center, detects degree of contamination of the filter ( 110 _ 1 ) installed in the filter box ( 100 ), and then transfer the detected sensing information to the controller ( 330 ).",
"This detector ( 310 ) may includes a temperature sensor ( 120 _ 1 , 120 _ 2 ) installed on the hot zone in the data center, a infrared sensor ( 110 _ 2 ) for detecting degree of contamination installed in the filter box ( 100 ), and a microcontroller ( 312 ) for processing the signal sensed from the temperature sensor ( 120 _ 1 , 120 _ 2 ) and the infrared sensor ( 110 _ 2 ) and transferring the sensing information to a main controller ( 332 ) of the controller ( 330 ).",
"[0032] A power supply ( 320 ) selectively supplies the operating power to the exhaust blower ( 80 _ 1 , 80 _ 2 ) and air supply blower ( 90 _ 1 , 90 _ 2 ) depending on the control signal from the controller ( 300 ).",
"The power supply ( 320 ) is connected to the exhaust blower ( 80 _ 1 , 80 _ 2 ) and air supply blower ( 90 _ 1 , 90 _ 2 ), and includes magnets that are on or off depending on the control signal of the main controller ( 332 ) of the controller ( 330 ) and a block switch ( 322 ) that allows the user to manually block the power at the time of the malfunction of the magnet.",
"[0033] The controller ( 330 ) controls the operation of the exhaust blower ( 80 _ 1 , 80 _ 2 ) and air supply blower ( 90 _ 1 , 90 _ 2 ) by controlling the operation of the power supply ( 320 ) depend on the sensing information from the detector ( 310 ).",
"That is, the main controller ( 332 ) of the controller ( 330 ) controls whether the operation power is supplied to the exhaust blower ( 80 _ 1 , 80 _ 2 ) and air supply blower ( 90 _ 1 , 90 _ 2 ) connected to magnets (Magnet 1 , Magnet 2 ) or not, by selectively turning on/off the magnets (Magnet 1 , Magnet 2 ) of the power supply ( 320 ).",
"And, the main controller ( 332 ) may controls the blowing speed of the exhaust blower ( 80 _ 1 , 80 _ 2 ) and the air supply blower ( 90 _ 1 , 90 _ 2 ) by controlling the power amount supplied to the exhaust blower ( 80 _ 1 , 80 _ 2 ) and the air supply blower ( 90 _ 1 , 90 _ 2 ) through the magnets (Magnet 1 , Magnet 2 ) when the magnets (Magnet 1 , Magnet 2 ) is on state.",
"At this time, the main controller ( 332 ) eliminates a noise generated at the time of the on/off operation of the magnets (Magnet 1 , Magnet 2 ) using relays (Relay 1 , Relay 2 ).",
"Also, the main controller ( 332 ) determines the replacement necessity (replacement time) of the filter ( 110 _ 1 ) in the filter box ( 100 ) depending on the sensing information from the microcontroller ( 312 ), and may display the message requesting the replacement of the filter on display unit ( 334 ) if it is determined that the replacement is needed.",
"In addition, the main controller ( 332 ) generates the control signal turning off the magnets of the power supply ( 320 ) and transmits the signal to the power supply ( 320 ), if the blocking signal is received from the block switch ( 322 ) of the power supply ( 320 ).",
"[0034] FIG. 4 is a flowchart illustrating a method for managing the exhaust operation in the air conditioning management method according to an embodiment of the present invention.",
"[0035] The exhaust blower ( 81 _ 1 , 80 _ 2 ) for exhausting the hot air of the hot zone maintains a state that the power supply is usually turned off (step 410 ).",
"[0036] At this time, the micro controller ( 312 ) periodically checks the temperature of each hot zone using the temperature sensor ( 120 _ 1 , 120 _ 2 ) and transfers the sensing information from the temperature sensor ( 120 _ 1 , 120 _ 2 ) to the main controller ( 332 ) [0037] The main controller ( 332 ) compares the temperature of each hot zone with the preset reference temperature depending on the temperature information received from the micro controller ( 312 ) (step 420 ) [0038] At this time, if the temperature of a specific hot zone is more than the reference temperature, main controller ( 332 ) supplies the operation power to the exhaust blower (for example, 80_ 1 ) and the air supply blower (for example, 90_ 1 ) corresponding to the hot zone which the temperature is high by turning on the corresponding magnet (for example, Magnet 1 ) (step 430 ).",
"[0039] According to the supply of the operation power, if the exhaust blower ( 80 _ 1 ) and the air supply blower ( 90 _ 1 ) operate, the hot air of the corresponding hot zone is exhausted via the exhaust diffuser ( 30 _ 1 ) through the exhaust duct ( 40 _ 1 ) to the outside of the data center.",
"And, by the pressure of the air supply blower ( 90 _ 1 ), the outside air is supplied to the inside of the data center through the filter ( 100 _ 1 ), the air supply duct ( 71 _ 1 ) and the air flow panel ( 60 _ 1 ).",
"[0040] If the temperature of all hot zone is more than the reference temperature, the main controller ( 332 ) operates both the exhaust blower ( 80 _ 1 , 80 _ 2 ) and the air supply blower ( 90 _ 1 , 90 _ 2 ) by turning on all magnets (Magnet 1 , Magnet 2 ), thereby supplying the outside air to the inside of the data center simultaneously while exhausting the hot air of all hot zones.",
"At this time, the main controller ( 332 ) may detects the temperature of each hot zone in detail by subdividing the reference temperature, that is, using a plurality of temperatures which are different from each other.",
"Hereby, the main controller ( 332 ) may independently controls the blowing speed of each of the exhaust blower ( 80 _ 1 , 80 _ 2 ) and the air supply blower ( 90 _ 1 , 90 _ 2 ) by individually controlling the each power amount supplied to the exhaust blower ( 80 _ 1 , 80 _ 2 ) and the air supply blower ( 90 _ 1 , 90 _ 2 ).",
"[0041] While the exhaust blower ( 80 _ 1 ) and the air supply blower ( 90 _ 1 ) operate, by continuously checking the temperature of the corresponding hot zone by detector ( 310 ), the main controller ( 332 ) indentifies whether the temperature of the hot zone is lower than the reference temperature again (step 440 ).",
"[0042] If the temperature of the hot zone is lower than the reference temperature by exhausting the hot air to the outside and supplying the outside air, the main controller ( 332 ) blocks the power supply supplied to the exhaust blower ( 80 _ 1 ) and the air supply blower ( 90 _ 1 ) by turning off the magnet (Magnet 1 ).",
"[0043] The operations of the above described steps 410 through 440 are repeatedly preformed until a different manipulation (instruction) by an operator.",
"[0044] FIG. 5 is a flowchart illustrating a method for managing the replacement of an air supply filter in the air conditioning management method according to an embodiment of the present invention.",
"[0045] A infrared sensor ( 110 _ 2 ) periodically irradiates a filter ( 110 _ 1 ) with infrared rays, and then detects the reflected light amount, and transmits the results to a micro controller ( 312 ).",
"The micro controller ( 312 ) processes the sensing signal from a infrared sensor ( 110 _ 2 ) and measures a color index for the filter ( 110 _ 1 ) (step 510 ).",
"[0046] The micro controller ( 312 ) transmits the sensing information to the main controller ( 332 ) of the controller ( 330 ).",
"[0047] The main controller ( 332 ) determines whether the color index of the sensing information received from micro controller ( 312 ) is more than the preset reference value (step 520 ).",
"[0048] In these comparisons, after several sensing multiple color indexes of the filter ( 110 _ 1 ), the average value is can be compared with the reference value.",
"[0049] If the sensed color index is more than the reference value, the main controller ( 332 ) displays the message requesting the replacement of the filter on display unit ( 334 ) (step 530 ).",
"[0050] The above described embodiments of the present invention are for the purpose of illustration, it will be understood by those skilled in the art that various modifications, changes, replacements and addition may be made therein with departing from the spirit and scope of the appended claims, and these modifications and changes are said to belong to the scope of the following claims.",
"DESCRIPTION OF THE REFERENCE NUMERAL [0051] [0000] 10: server rack 20_1, 20_2: pyramid diffuser 30, 30_1, 30_2: exhaust diffuser 40, 40_1, 40_2: exhaust duct 50: access door 60: air flow panel 70_1, 70_2: air supply duct 80_1, 80_2: exhaust blower 90_1, 90_2: air supply blower 100: filter box 110_1: filter 110_2: infrared sensor 120_1, 120_2: temperature sensor 130: control device 310: detector 312: micro controllers 320: power supply 322: block switch 330: The controller 332: main controller 334: the display unit"
] |
This is a continuation of application Ser. No. 07/327,674 filed Mar. 23, 1989 abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to an electronic flash control device for a TTL light control type camera, and more particularly to an electronic flash control device which is free from the difficulty that light emission by the electronic flash is stopped by a noise component occurring before a suitable quantity of output light is obtained.
When it is necessary to photograph an object having a low luminance or to correct the amount of exposure, an electronic flash is generally used to increase the luminance of the object. The electronic flash is either built into the camera or is provided separately and can be connected to the camera. Whether the electronic flash is built into the camera or provided separately from the camera, it is essential to control the light emitting conditions of the electronic flash so that the amount of light applied to the object by the electronic flash has a predetermined value. In order to meet this requirement, the camera is provided with an electronic flash control device.
The electronic flash control device will be described with reference to a TTL light control type camera employing an electronic flash. FIG. 4 shows an example of a camera of this type. More specifically, FIG. 4 is a block diagram outlining the arrangement of a camera having an automatic focusing (AF) function and a built-in electronic flash proposed by the present applicant.
First, the arrangement of the camera shown in FIG. 4 will briefly be described. In FIG. 4, reference numeral 31 designates a camera body, and 11 represents a photographic lens mounted on the camera body 31.
The photographic lens 11 includes a lens system 15 including a focusing lens 13 which is movable along the optical axis and contributes to the focusing operation, and a drive force transmitting mechanism 17 for transmitting a drive force from a drive source provided for the camera body 31 to the movable lens 13. The photographic lens 11 further includes a lens ROM (read-only memory) 19 storing aperture value data of the photographic lens, position data of the movable lens 13, and data as to whether or not operating the electronic flash built into the camera body is suitable for the photographic lens, and a group of electrical contacts 21 which are connected to electrical contacts 57 on the camera body 31.
On the other hand, the camera body 31 includes an optical system having a main mirror 33, an auxiliary mirror 35, a focusing screen 37, and a pentagonal prism 39, an image pickup section 41 used for an automatic focusing operation, a drive mechanism 43 for driving the movable lens 13 in the photographic lens 11, a light detecting element 45 used for automatic exposure (AE) control for the purpose of TTL light control, a light detecting element 47 operated when the electronic flash is used, a central display section 49 for displaying camera conditions, a display unit 51 provided in the viewfinder for indicating an AF or AE mode, the built-in electronic flash 53, a sequence motor 55 for winding or rewinding the film, a group of electrical contacts 57 provided on the side of the camera body which are connected to the group of electrical contacts 21 on the side of the photographic lens, a release switch 59, and a synchronizing contact 61 such as an X contact.
The camera body 31 further includes a microcomputer, namely, an IPU (indication processing unit) 71 for controlling the central display section 49, a PCU (power control unit) 73 having an E 2 PROM 73a for interfacing with the image pickup section 41 and controlling the sequence motor 55 and an AF motor 43, the lens stop and the shutter release magnet, another microcomputer, namely, a DPU (data processing unit) 75 for performing photometric arithmetic operations and controlling the display unit 51 in the viewfinder, etc., and a central control microcomputer, namely, a CPU (central processing unit) 77. The CPU 77 controls the IPU 71, the PCU 73, the DPU 75, and the lens ROM 19 in the photographic lens 11.
The above-described built-in electronic flash 53 is provided above the pentagonal prism 39 and substantially at the middle of the camera body 31 so that the light flash can be readily applied to an object. When the electronic flash 53 is not in use, its light flash emitting section is retracted into the camera body. When it is in use, the light flash emitting section is protruded therefrom by operating a push button (not shown). The camera is designed so that an auxiliary electronic flash can be additionally connected thereto.
Next, an electronic flash control device for the above-described camera will be described. FIG. 5 is a diagram showing the above-described electronic light flash 53 and the electronic flash control device in detail. In FIG. 5, reference numeral 81 designates the electronic flash control device. The device 81 includes as essential components the CPU 77, the DPU 75, the PCU 73, the light detecting element 47, the release switch 59 and the X contact 61. The electronic flash 53 includes a booster circuit 53a, a main capacitor 53b, a light emitting circuit 53d having a light emitting tube 53c, and a light emission stopping circuit 53e. The electronic flash 53 is connected to the electronic flash control circuit 81 through a trigger signal terminal 53f and a quench signal terminal 53g. When necessary, the aforementioned auxiliary electronic flash is connected to the electronic flash control circuit 81 through auxiliary electronic flash connecting contacts corresponding to the above-described contacts 53f and 53g which are provided at predetermined positions on the camera body 31.
The operation of the electronic flash control device 81 thus constructed will be described with reference to the timing diagrams shown in FIGS. 6(A) through 6(J).
The release switch 59 is turned on after the camera has selected the electronic flash operation mode. Then, the CPU 77, after carrying out a series of processing operations, starts detecting the variation of the voltage at the X contact. In response to the variation of the voltage at the X contact (SWX in FIG. 6(A)) which occurs when the shutter is fully opened, the CPU 77 supplies a trigger signal X TRIG shown in FIG. 6(B) to light emitting circuit 53d in the electronic flash 53 via trigger signal terminal 53f. In response to the trigger signal, the light emitting circuit 53d supplies an electrical signal S X shown in FIG. 6(C) to the light emitting tube 53c. As a result, the light emitting tube 53c emits light. (See FIG. 6(G)).
On the other hand, an integrator circuit 75a in the DPU 75 integrates the output signal of the light detecting element 47 in response to an integration start signal S S shown in FIG. 6(D) which the CPU 77 outputs in response to the trigger signal. The integration voltage S I of the integrating circuit, as shown in FIG. 6(E), gradually increases with time, and abruptly increases with the emission of light from the light emitting tube. The integration voltage S I is applied to one input terminal of a comparator 75b.
The CPU 77 applies a digital signal S D to a D/A (digital to analog) converter 75c prior to every photographing operation. The digital signal represents a suitable exposure value determined in accordance with the ISO data of the film loaded in the camera or exposure correction data when available. The digital signal S D is subjected to digital-to-analog conversion by the D/A converter 75c, the output of which is applied to the other input terminal of the comparator 75b. The output terminal of the comparator 75b is connected to one input terminal of an AND circuit in a quench signal output regulating circuit 75d in the DPU 75.
When, in the circuit thus constructed, the integration voltage S I reaches a reference value S O , the comparator 75b applies a signal to the AND circuit in the quench signal output regulating circuit 75d so that the quench signal is generated (in a manner to be described in more detail later). When, with an enable signal S E applied to the other input terminal of the AND circuit by the CPU 77, the integration voltage S I reaches the reference value, the regulating circuit 75d applies a quench signal Q U shown in FIG. 6(F) to the light emission stopping circuit 53e. In response to the quench signal, the emission of light of the electronic flash 53 is quickly suppressed as shown in FIG. 6(G).
The present applicant has conducted extensive research on the electronic flash control circuit described above and recognized that the output timing of the enable signal S E is very important. That is, depending on the enable signal, the control circuit may operate erroneously.
When the CPU 77 supplies the enable signal S E as shown in FIG. 6(H) to the quench signal output regulating circuit 75d before a noise pulse N T occurs within the electrical signal S X in response to the trigger signal as shown in FIG. 6(C), the circuit is operated erroneously and a false quench signal Q UF is produced as shown in FIG. 6(I), so that no light is emitted (See FIG. 6(J).) In practice, such noise pulses are often produced by the light emitting tube, and accordingly, in order to perform the emission of light correctly, it is essential to use a light emitting tube having excellent characteristics. As a result, during manufacture, it is necessary to perform an additional operation of selecting light emitting tubes suitable for the electronic flash control device.
In view of the foregoing, an object of the present invention is to provide an electronic flash control device which is free from the difficulty of the emission of the light flash being stopped by a noise component before a suitable amount of light is obtained.
SUMMARY OF THE INVENTION
The foregoing and other objects of the present invention have been achieved by the provision of an electronic flash control device for a TTL light control type camera comprising means for applying a trigger signal to an electronic flash to cause the electronic flash to emit light; and means for applying a quench signal to said electronic flash when, with an enable signal being supplied, the quantity of light from an object to be photographed reaches a predetermined value, which device, according to the invention, comprises means for supplying the enable signal at a predetermined time instant after a noise signal attributing to the trigger signal occurs.
In the inventive electronic flash control device, the predetermined time instant preferably occurs around the start of the emission of the light flash. It goes without saying that, when the light flash has been emitted, the time instant should occur before the output of the light detecting element which receives the light flash reaches a predetermined value (in the above-described example, the reference value S O ).
Further, in the electronic flash control device of the invention, the predetermined time instant preferably occurs when a predetermined period of time has passed after the generation of the trigger signal. Data for selecting the predetermined period of time is stored in an E 2 PROM (electrically erasable programmable ROM).
In the electronic flash control device thus constructed, the enable signal can be applied to the quench signal outputting means after the noise accompanying the trigger signal is decreased, whereby erroneous operation due to the noise can be prevented.
Furthermore, the timing of production of the enable signal is determined according to the data stored in the E 2 PROM, which can be changed with ease. Thus, changes in the timing of production of the noise, such as may occur when a light emitting tube of a different lot is used or a different model of light emitting tube is employed, can readily be accommodated.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the present invention will be apparent from the following description taken in connection with the accompanying drawings, wherein:
FIG. 1 is a block diagram used for a description of the function of an enable signal supplying device in an example of an electronic flash control device constructed according to the present invention;
FIGS. 2(A) and 2(B) are flow charts for a description of the operation of the electronic flash control device of the present invention;
FIGS. 3(A) through 3(H) are diagrams describing the operation of the electronic flash control device of the present invention;
FIG. 4 is an explanatory diagram for a description of the arrangement of a camera to which the electronic flash control device of the present invention is applied;
FIG. 5 is a circuit diagram, partly as a block diagram, for a description of the operation of the electronic flash control device according to the present invention; and
FIG. 6(A) through 6(J) are waveform diagrams used in describing the prior art.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An example of an electronic flash control device constructed according to the present invention which is applied, by way of example, to a built-in electronic flash of an AF camera will be described. However, it should be noted that the invention is not limited thereto or thereby. That is, the technical concept of the invention is applicable to an AF camera connected to the auxiliary electronic flash, or to silver salt photographic cameras other than TTL light control type cameras, and to electronic still cameras.
First, various arrangements of the electronic flash control device according to the present invention will be described with reference to FIGS. 1 and 5.
A device for applying the trigger signal to the electronic flash 53 essentially includes the release switch 59, the X contact 61, and the CPU 77.
A device for applying the quench signal to the electronic flash 53 when, with the enable signal present, the quantity of light from the object reaches a predetermined value essentially includes the CPU 77, the light detecting element 47, the integrator circuit 75a, the comparator 75b, the D/A converter 75, and the quench signal output regulating circuit 75d in the DPU 75.
A device for supplying the enable signal at a predetermined time instant after the occurrence of noise in response to the trigger signal essentially includes the E 2 PROM 73a of the PCU 73 and the CPU 77. FIG. 1 is a block diagram showing the enable signal supplying device in more detail. In FIG. 1, reference numeral 90 designates the enable signal supplying device.
The enable signal supplying device 90 utilizes a timer 77a and a time setting unit 77b included in the CPU 77. Data indicating a predetermined time period stored in the E 2 PROM 73a of the PCU 73 is applied to the time setting unit 77b to be set in the timer 77a. In response to the trigger signal X TRIG , the timer 77a starts counting the time thus set, and outputs the enable signal S E at the end of the time counting operation.
The data indicating the predetermined time stored in the E 2 PROM 73a is determined through experiments depending on the type of electronic flash and light emitting tube used. The control device may be designed so that many different data timing signals may be stored in the E 2 PROM 73a in advance. Thus, when an electronic flash is connected to the camera, the data signal corresponding to the connected electronic flash is read out.
FIGS. 2(A) and 2(B) are flowcharts describing the operation of the CPU 77 which controls the trigger signal supplying device, the quench signal supplying device, and the enable signal supplying device. The operation of the electronic flash control device of the present invention will be described with reference to FIGS. 2 and 5.
First, the electronic flash control device is initialized (Step 101 in FIG. 2(A)).
The initialization is achieved by inhibiting the TTL integration, i.e., by inhibiting the integrating of the input of the light detecting element 47 and by inhibiting the outputting of the quench signal. More specifically, the integrating of the output of the light detecting element 47 is inhibited by raising the port for the integration starting signal S S of the CPU 77 to "1" so that a transistor Tr short circuits a capacitor C 1 in the integrating circuit 75. The outputting of the quench signal is inhibited by setting port for the enable signal S E of the CPU 77 to "0".
Thereafter, in the camera, a photometric arithmetic operation for AE (automatic exposure control) is carried out according to the program (Step 103). In this operation, a suitable shutter speed Tv and a suitable aperture value Av are determined. In addition, a data signal Sv indicating the ISO of the photographing film, and a data signal Xv indicating an exposure correction value when specified by the photographer are loaded in the CPU 77. Under this condition, the CPU 77 detects a voltage at the port to which the release switch 59 is connected. When the detected voltage is at a high level, Step 103 is repeated (Step 105). When the detected voltage is at a low level (i.e., the release switch is depressed), the CPU 77, ending the photometric arithmetic operation, controls the main mirror 33, the auxiliary mirror 35 (FIG. 4) and the lens stop (Step 107).
Then, the CPU 77 applies data to the D/A converter 75c which indicates an exposure value suitable for photographing the present frame which is determined from the data Sv, Xv, etc., corresponding to the integrated voltage of the light detecting element 47 (Step 109). In this case, the data is output as an eight-bit signal. Data for counting the predetermined time period is then output by the E 2 PROM 73a and set in the timer 77a (Step 110).
Upon completion of the control of the mirrors and the lens stop, a magnet holding a front curtain is deenergized to run the front curtain (Step 111). An interrupt with the X contact turned on is allowed so that the signal of the X contact turned on upon completion of the running of the front curtain can be preferentially detected (Step 113). After allowing the interrupt, the CPU 77 carries out a time counting operation for controlling the exposure time (Step 131). The interrupt operation is carried out during the time counting operation.
The operation of the electronic flash control device in the interrupt processing carried out when the X contact is turned on will be described with reference to FIG. 2(B) and FIGS. 3(A) through 3(H) which are timing diagrams for the electronic flash control device of the present invention.
When, during the time counting operation of Step 131, an interrupt occurs with the variation of the voltage of the X contact at time t 1 as shown in FIG. 3(A), the CPU 77 applies a trigger signal X TRIG at time t 2 as shown in FIG. 3(B) to the light emitting circuit 53d of the electronic flash 53 (Step 121 in FIG. 2(B)). In response to the trigger signal, the light emitting circuit 53d applies an electrical signal S X as shown in FIG. 3(C) to the light emitting tube 53c. In response to electrical signal S X , the light emitting tube 53c emits light as shown in FIG. 3(G).
The integrating circuit 75a in the DPU 75 integrates the output signal of the light detecting element 47 in response to the integration starting signal S S output by the CPU 77 as shown in FIG. 3(D). The integrated voltage S I , as shown in FIG. 3(E), gradually increases with time, and abruptly increases upon emission of the light. The integrated voltage S I is applied to one input terminal of the comparator 75b. A reference value S O indicating the amount of light suitable for the present photographing operation is applied to the other input terminal of comparator 75b. When the integrated voltage S I exceeds the reference value S O comparator 75b applies a signal to one input terminal of the AND circuit in the quench signal output regulating circuit 75d which is used to form the quench signal.
In response to the trigger signal XTRIG' the timer means 77a of the enable signal supplying device 90 (FIG. 1) starts a time counting operation (Step 123). At time t 3 , after a predetermined time T O has elapsed since time t 2 , the CPU applies the enable signal SE to the other input terminal of the AND circuit in the quench signal regulating circuit (Step 124).
When the enable signal SE and the output signal from comparator 75b have been supplied to the AND gate as described above, the regulating circuit 75d applies the quench signal QU to the electronic flash 53 at time t 4 as shown in FIG. 3(F). The emission of light by the electronic flash is quickly suppressed by the quench signal QU (the solid line after time t 4 as shown in FIG. 3(G)).
Next, the CPU 77 inhibits the interrupt occurring with the X contact turned on (SWX "on") (Step 125).
A predetermined time after the release of the shutter, driving of the rear curtain is started (Steps 131 and 133 of FIG. 2(A)). Thereafter, the film is wound (Step 135). Thus, one frame of a photographing operation has been accomplished. The above-described operation is then repeated beginning with Step 101.
While the present invention has been described with reference to a preferred embodiment, it should be noted that the invention is not limited thereto or thereby.
The trigger signal outputting device, the quench signal outputting device, and the enable signal supplying device are not limited to those which have been described above, that is, they may be replaced with other suitable devices.
In the above-described embodiment, integrating the output of the light detecting element and counting the time until the production of the enable signal are started in response to the trigger signal. However, it is obvious that the start time is not always limited to when the trigger signal is provided.
As is apparent from the above description, in the electronic flash control device of the present invention, the enable signal SE can be applied to the quench signal outputting means 75d after the noise accompanying the trigger signal has dissipated, whereby erroneous operations due to the noise can be prevented. Thus, the emission of light of the electronic flash is stopped when the quantity of light received by the light detecting element has reached the predetermined value. Accordingly, the photographing operation can be achieved satisfactorily with the electronic flash.
Furthermore, the employment of the E 2 PROM makes it possible to readily change the timing of application of the enable signal. Hence, there is no difficulty in accommodating changes in the timing of production of the noise, such as when a light emitting tube of a different lot is used or a different light emitting tube is employed. | An electronic flash control device makes sure that the emission of light of an electronic flash is not impaired by a noise component signal prior to generation of a suitable quantity of light by the flash. A trigger signal is applied by the control device to allow the flash to emit light. An enable signal is supplied to a quenching circuit a predetermined time after the noise of the trigger signal has been produced. When the quantity of light from an object to be photographed by the camera reaches a certain value and the enable signal occurs, the quench circuit suppresses the emission of light by the electronic flash. | Condense the core contents of the given document. | [
"This is a continuation of application Ser.",
"No. 07/327,674 filed Mar. 23, 1989 abandoned.",
"BACKGROUND OF THE INVENTION The present invention relates to an electronic flash control device for a TTL light control type camera, and more particularly to an electronic flash control device which is free from the difficulty that light emission by the electronic flash is stopped by a noise component occurring before a suitable quantity of output light is obtained.",
"When it is necessary to photograph an object having a low luminance or to correct the amount of exposure, an electronic flash is generally used to increase the luminance of the object.",
"The electronic flash is either built into the camera or is provided separately and can be connected to the camera.",
"Whether the electronic flash is built into the camera or provided separately from the camera, it is essential to control the light emitting conditions of the electronic flash so that the amount of light applied to the object by the electronic flash has a predetermined value.",
"In order to meet this requirement, the camera is provided with an electronic flash control device.",
"The electronic flash control device will be described with reference to a TTL light control type camera employing an electronic flash.",
"FIG. 4 shows an example of a camera of this type.",
"More specifically, FIG. 4 is a block diagram outlining the arrangement of a camera having an automatic focusing (AF) function and a built-in electronic flash proposed by the present applicant.",
"First, the arrangement of the camera shown in FIG. 4 will briefly be described.",
"In FIG. 4, reference numeral 31 designates a camera body, and 11 represents a photographic lens mounted on the camera body 31.",
"The photographic lens 11 includes a lens system 15 including a focusing lens 13 which is movable along the optical axis and contributes to the focusing operation, and a drive force transmitting mechanism 17 for transmitting a drive force from a drive source provided for the camera body 31 to the movable lens 13.",
"The photographic lens 11 further includes a lens ROM (read-only memory) 19 storing aperture value data of the photographic lens, position data of the movable lens 13, and data as to whether or not operating the electronic flash built into the camera body is suitable for the photographic lens, and a group of electrical contacts 21 which are connected to electrical contacts 57 on the camera body 31.",
"On the other hand, the camera body 31 includes an optical system having a main mirror 33, an auxiliary mirror 35, a focusing screen 37, and a pentagonal prism 39, an image pickup section 41 used for an automatic focusing operation, a drive mechanism 43 for driving the movable lens 13 in the photographic lens 11, a light detecting element 45 used for automatic exposure (AE) control for the purpose of TTL light control, a light detecting element 47 operated when the electronic flash is used, a central display section 49 for displaying camera conditions, a display unit 51 provided in the viewfinder for indicating an AF or AE mode, the built-in electronic flash 53, a sequence motor 55 for winding or rewinding the film, a group of electrical contacts 57 provided on the side of the camera body which are connected to the group of electrical contacts 21 on the side of the photographic lens, a release switch 59, and a synchronizing contact 61 such as an X contact.",
"The camera body 31 further includes a microcomputer, namely, an IPU (indication processing unit) 71 for controlling the central display section 49, a PCU (power control unit) 73 having an E 2 PROM 73a for interfacing with the image pickup section 41 and controlling the sequence motor 55 and an AF motor 43, the lens stop and the shutter release magnet, another microcomputer, namely, a DPU (data processing unit) 75 for performing photometric arithmetic operations and controlling the display unit 51 in the viewfinder, etc.",
", and a central control microcomputer, namely, a CPU (central processing unit) 77.",
"The CPU 77 controls the IPU 71, the PCU 73, the DPU 75, and the lens ROM 19 in the photographic lens 11.",
"The above-described built-in electronic flash 53 is provided above the pentagonal prism 39 and substantially at the middle of the camera body 31 so that the light flash can be readily applied to an object.",
"When the electronic flash 53 is not in use, its light flash emitting section is retracted into the camera body.",
"When it is in use, the light flash emitting section is protruded therefrom by operating a push button (not shown).",
"The camera is designed so that an auxiliary electronic flash can be additionally connected thereto.",
"Next, an electronic flash control device for the above-described camera will be described.",
"FIG. 5 is a diagram showing the above-described electronic light flash 53 and the electronic flash control device in detail.",
"In FIG. 5, reference numeral 81 designates the electronic flash control device.",
"The device 81 includes as essential components the CPU 77, the DPU 75, the PCU 73, the light detecting element 47, the release switch 59 and the X contact 61.",
"The electronic flash 53 includes a booster circuit 53a, a main capacitor 53b, a light emitting circuit 53d having a light emitting tube 53c, and a light emission stopping circuit 53e.",
"The electronic flash 53 is connected to the electronic flash control circuit 81 through a trigger signal terminal 53f and a quench signal terminal 53g.",
"When necessary, the aforementioned auxiliary electronic flash is connected to the electronic flash control circuit 81 through auxiliary electronic flash connecting contacts corresponding to the above-described contacts 53f and 53g which are provided at predetermined positions on the camera body 31.",
"The operation of the electronic flash control device 81 thus constructed will be described with reference to the timing diagrams shown in FIGS. 6(A) through 6(J).",
"The release switch 59 is turned on after the camera has selected the electronic flash operation mode.",
"Then, the CPU 77, after carrying out a series of processing operations, starts detecting the variation of the voltage at the X contact.",
"In response to the variation of the voltage at the X contact (SWX in FIG. 6(A)) which occurs when the shutter is fully opened, the CPU 77 supplies a trigger signal X TRIG shown in FIG. 6(B) to light emitting circuit 53d in the electronic flash 53 via trigger signal terminal 53f.",
"In response to the trigger signal, the light emitting circuit 53d supplies an electrical signal S X shown in FIG. 6(C) to the light emitting tube 53c.",
"As a result, the light emitting tube 53c emits light.",
"(See FIG. 6(G)).",
"On the other hand, an integrator circuit 75a in the DPU 75 integrates the output signal of the light detecting element 47 in response to an integration start signal S S shown in FIG. 6(D) which the CPU 77 outputs in response to the trigger signal.",
"The integration voltage S I of the integrating circuit, as shown in FIG. 6(E), gradually increases with time, and abruptly increases with the emission of light from the light emitting tube.",
"The integration voltage S I is applied to one input terminal of a comparator 75b.",
"The CPU 77 applies a digital signal S D to a D/A (digital to analog) converter 75c prior to every photographing operation.",
"The digital signal represents a suitable exposure value determined in accordance with the ISO data of the film loaded in the camera or exposure correction data when available.",
"The digital signal S D is subjected to digital-to-analog conversion by the D/A converter 75c, the output of which is applied to the other input terminal of the comparator 75b.",
"The output terminal of the comparator 75b is connected to one input terminal of an AND circuit in a quench signal output regulating circuit 75d in the DPU 75.",
"When, in the circuit thus constructed, the integration voltage S I reaches a reference value S O , the comparator 75b applies a signal to the AND circuit in the quench signal output regulating circuit 75d so that the quench signal is generated (in a manner to be described in more detail later).",
"When, with an enable signal S E applied to the other input terminal of the AND circuit by the CPU 77, the integration voltage S I reaches the reference value, the regulating circuit 75d applies a quench signal Q U shown in FIG. 6(F) to the light emission stopping circuit 53e.",
"In response to the quench signal, the emission of light of the electronic flash 53 is quickly suppressed as shown in FIG. 6(G).",
"The present applicant has conducted extensive research on the electronic flash control circuit described above and recognized that the output timing of the enable signal S E is very important.",
"That is, depending on the enable signal, the control circuit may operate erroneously.",
"When the CPU 77 supplies the enable signal S E as shown in FIG. 6(H) to the quench signal output regulating circuit 75d before a noise pulse N T occurs within the electrical signal S X in response to the trigger signal as shown in FIG. 6(C), the circuit is operated erroneously and a false quench signal Q UF is produced as shown in FIG. 6(I), so that no light is emitted (See FIG. 6(J).) In practice, such noise pulses are often produced by the light emitting tube, and accordingly, in order to perform the emission of light correctly, it is essential to use a light emitting tube having excellent characteristics.",
"As a result, during manufacture, it is necessary to perform an additional operation of selecting light emitting tubes suitable for the electronic flash control device.",
"In view of the foregoing, an object of the present invention is to provide an electronic flash control device which is free from the difficulty of the emission of the light flash being stopped by a noise component before a suitable amount of light is obtained.",
"SUMMARY OF THE INVENTION The foregoing and other objects of the present invention have been achieved by the provision of an electronic flash control device for a TTL light control type camera comprising means for applying a trigger signal to an electronic flash to cause the electronic flash to emit light;",
"and means for applying a quench signal to said electronic flash when, with an enable signal being supplied, the quantity of light from an object to be photographed reaches a predetermined value, which device, according to the invention, comprises means for supplying the enable signal at a predetermined time instant after a noise signal attributing to the trigger signal occurs.",
"In the inventive electronic flash control device, the predetermined time instant preferably occurs around the start of the emission of the light flash.",
"It goes without saying that, when the light flash has been emitted, the time instant should occur before the output of the light detecting element which receives the light flash reaches a predetermined value (in the above-described example, the reference value S O ).",
"Further, in the electronic flash control device of the invention, the predetermined time instant preferably occurs when a predetermined period of time has passed after the generation of the trigger signal.",
"Data for selecting the predetermined period of time is stored in an E 2 PROM (electrically erasable programmable ROM).",
"In the electronic flash control device thus constructed, the enable signal can be applied to the quench signal outputting means after the noise accompanying the trigger signal is decreased, whereby erroneous operation due to the noise can be prevented.",
"Furthermore, the timing of production of the enable signal is determined according to the data stored in the E 2 PROM, which can be changed with ease.",
"Thus, changes in the timing of production of the noise, such as may occur when a light emitting tube of a different lot is used or a different model of light emitting tube is employed, can readily be accommodated.",
"BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the present invention will be apparent from the following description taken in connection with the accompanying drawings, wherein: FIG. 1 is a block diagram used for a description of the function of an enable signal supplying device in an example of an electronic flash control device constructed according to the present invention;",
"FIGS. 2(A) and 2(B) are flow charts for a description of the operation of the electronic flash control device of the present invention;",
"FIGS. 3(A) through 3(H) are diagrams describing the operation of the electronic flash control device of the present invention;",
"FIG. 4 is an explanatory diagram for a description of the arrangement of a camera to which the electronic flash control device of the present invention is applied;",
"FIG. 5 is a circuit diagram, partly as a block diagram, for a description of the operation of the electronic flash control device according to the present invention;",
"and FIG. 6(A) through 6(J) are waveform diagrams used in describing the prior art.",
"DESCRIPTION OF THE PREFERRED EMBODIMENT An example of an electronic flash control device constructed according to the present invention which is applied, by way of example, to a built-in electronic flash of an AF camera will be described.",
"However, it should be noted that the invention is not limited thereto or thereby.",
"That is, the technical concept of the invention is applicable to an AF camera connected to the auxiliary electronic flash, or to silver salt photographic cameras other than TTL light control type cameras, and to electronic still cameras.",
"First, various arrangements of the electronic flash control device according to the present invention will be described with reference to FIGS. 1 and 5.",
"A device for applying the trigger signal to the electronic flash 53 essentially includes the release switch 59, the X contact 61, and the CPU 77.",
"A device for applying the quench signal to the electronic flash 53 when, with the enable signal present, the quantity of light from the object reaches a predetermined value essentially includes the CPU 77, the light detecting element 47, the integrator circuit 75a, the comparator 75b, the D/A converter 75, and the quench signal output regulating circuit 75d in the DPU 75.",
"A device for supplying the enable signal at a predetermined time instant after the occurrence of noise in response to the trigger signal essentially includes the E 2 PROM 73a of the PCU 73 and the CPU 77.",
"FIG. 1 is a block diagram showing the enable signal supplying device in more detail.",
"In FIG. 1, reference numeral 90 designates the enable signal supplying device.",
"The enable signal supplying device 90 utilizes a timer 77a and a time setting unit 77b included in the CPU 77.",
"Data indicating a predetermined time period stored in the E 2 PROM 73a of the PCU 73 is applied to the time setting unit 77b to be set in the timer 77a.",
"In response to the trigger signal X TRIG , the timer 77a starts counting the time thus set, and outputs the enable signal S E at the end of the time counting operation.",
"The data indicating the predetermined time stored in the E 2 PROM 73a is determined through experiments depending on the type of electronic flash and light emitting tube used.",
"The control device may be designed so that many different data timing signals may be stored in the E 2 PROM 73a in advance.",
"Thus, when an electronic flash is connected to the camera, the data signal corresponding to the connected electronic flash is read out.",
"FIGS. 2(A) and 2(B) are flowcharts describing the operation of the CPU 77 which controls the trigger signal supplying device, the quench signal supplying device, and the enable signal supplying device.",
"The operation of the electronic flash control device of the present invention will be described with reference to FIGS. 2 and 5.",
"First, the electronic flash control device is initialized (Step 101 in FIG. 2(A)).",
"The initialization is achieved by inhibiting the TTL integration, i.e., by inhibiting the integrating of the input of the light detecting element 47 and by inhibiting the outputting of the quench signal.",
"More specifically, the integrating of the output of the light detecting element 47 is inhibited by raising the port for the integration starting signal S S of the CPU 77 to "1"",
"so that a transistor Tr short circuits a capacitor C 1 in the integrating circuit 75.",
"The outputting of the quench signal is inhibited by setting port for the enable signal S E of the CPU 77 to "0".",
"Thereafter, in the camera, a photometric arithmetic operation for AE (automatic exposure control) is carried out according to the program (Step 103).",
"In this operation, a suitable shutter speed Tv and a suitable aperture value Av are determined.",
"In addition, a data signal Sv indicating the ISO of the photographing film, and a data signal Xv indicating an exposure correction value when specified by the photographer are loaded in the CPU 77.",
"Under this condition, the CPU 77 detects a voltage at the port to which the release switch 59 is connected.",
"When the detected voltage is at a high level, Step 103 is repeated (Step 105).",
"When the detected voltage is at a low level (i.e., the release switch is depressed), the CPU 77, ending the photometric arithmetic operation, controls the main mirror 33, the auxiliary mirror 35 (FIG.",
"4) and the lens stop (Step 107).",
"Then, the CPU 77 applies data to the D/A converter 75c which indicates an exposure value suitable for photographing the present frame which is determined from the data Sv, Xv, etc.",
", corresponding to the integrated voltage of the light detecting element 47 (Step 109).",
"In this case, the data is output as an eight-bit signal.",
"Data for counting the predetermined time period is then output by the E 2 PROM 73a and set in the timer 77a (Step 110).",
"Upon completion of the control of the mirrors and the lens stop, a magnet holding a front curtain is deenergized to run the front curtain (Step 111).",
"An interrupt with the X contact turned on is allowed so that the signal of the X contact turned on upon completion of the running of the front curtain can be preferentially detected (Step 113).",
"After allowing the interrupt, the CPU 77 carries out a time counting operation for controlling the exposure time (Step 131).",
"The interrupt operation is carried out during the time counting operation.",
"The operation of the electronic flash control device in the interrupt processing carried out when the X contact is turned on will be described with reference to FIG. 2(B) and FIGS. 3(A) through 3(H) which are timing diagrams for the electronic flash control device of the present invention.",
"When, during the time counting operation of Step 131, an interrupt occurs with the variation of the voltage of the X contact at time t 1 as shown in FIG. 3(A), the CPU 77 applies a trigger signal X TRIG at time t 2 as shown in FIG. 3(B) to the light emitting circuit 53d of the electronic flash 53 (Step 121 in FIG. 2(B)).",
"In response to the trigger signal, the light emitting circuit 53d applies an electrical signal S X as shown in FIG. 3(C) to the light emitting tube 53c.",
"In response to electrical signal S X , the light emitting tube 53c emits light as shown in FIG. 3(G).",
"The integrating circuit 75a in the DPU 75 integrates the output signal of the light detecting element 47 in response to the integration starting signal S S output by the CPU 77 as shown in FIG. 3(D).",
"The integrated voltage S I , as shown in FIG. 3(E), gradually increases with time, and abruptly increases upon emission of the light.",
"The integrated voltage S I is applied to one input terminal of the comparator 75b.",
"A reference value S O indicating the amount of light suitable for the present photographing operation is applied to the other input terminal of comparator 75b.",
"When the integrated voltage S I exceeds the reference value S O comparator 75b applies a signal to one input terminal of the AND circuit in the quench signal output regulating circuit 75d which is used to form the quench signal.",
"In response to the trigger signal XTRIG'",
"the timer means 77a of the enable signal supplying device 90 (FIG.",
"1) starts a time counting operation (Step 123).",
"At time t 3 , after a predetermined time T O has elapsed since time t 2 , the CPU applies the enable signal SE to the other input terminal of the AND circuit in the quench signal regulating circuit (Step 124).",
"When the enable signal SE and the output signal from comparator 75b have been supplied to the AND gate as described above, the regulating circuit 75d applies the quench signal QU to the electronic flash 53 at time t 4 as shown in FIG. 3(F).",
"The emission of light by the electronic flash is quickly suppressed by the quench signal QU (the solid line after time t 4 as shown in FIG. 3(G)).",
"Next, the CPU 77 inhibits the interrupt occurring with the X contact turned on (SWX "on") (Step 125).",
"A predetermined time after the release of the shutter, driving of the rear curtain is started (Steps 131 and 133 of FIG. 2(A)).",
"Thereafter, the film is wound (Step 135).",
"Thus, one frame of a photographing operation has been accomplished.",
"The above-described operation is then repeated beginning with Step 101.",
"While the present invention has been described with reference to a preferred embodiment, it should be noted that the invention is not limited thereto or thereby.",
"The trigger signal outputting device, the quench signal outputting device, and the enable signal supplying device are not limited to those which have been described above, that is, they may be replaced with other suitable devices.",
"In the above-described embodiment, integrating the output of the light detecting element and counting the time until the production of the enable signal are started in response to the trigger signal.",
"However, it is obvious that the start time is not always limited to when the trigger signal is provided.",
"As is apparent from the above description, in the electronic flash control device of the present invention, the enable signal SE can be applied to the quench signal outputting means 75d after the noise accompanying the trigger signal has dissipated, whereby erroneous operations due to the noise can be prevented.",
"Thus, the emission of light of the electronic flash is stopped when the quantity of light received by the light detecting element has reached the predetermined value.",
"Accordingly, the photographing operation can be achieved satisfactorily with the electronic flash.",
"Furthermore, the employment of the E 2 PROM makes it possible to readily change the timing of application of the enable signal.",
"Hence, there is no difficulty in accommodating changes in the timing of production of the noise, such as when a light emitting tube of a different lot is used or a different light emitting tube is employed."
] |
This is a divisional of application Ser. No. 08/819,375, filed Mar. 17, 1997.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a harvester for leafy vegetables and a process for harvesting leafy vegetables.
2. Description of the Related Art
Harvesting young or early growth leafy vegetables presents particular problems not found when harvesting other vegetables. By “leafy vegetables” it is meant that family of specialty lettuces and other leafy greens which, when mixed together for sale and consumption are sometimes referred to as “spring mix,” “mixed greens,” or “baby greens.” For example, this includes lettuces, such as green romaine, red romaine, sierra, lola rosa, tango, green leaf, red leaf, little gem, red butter, read oak, red perella and green perella. It also includes greens such as arugula, maxine, red mustard, green mustard, spinach, tat tai, red chard and red russian kale. If such leafy vegetables are grown under certain conditions, the harvested produce can be certified as organically grown.
Harvesters are known for cutting some vegetables such as spinach, cabbage, watercress and the like. Recently, consumer demand has required harvesting a variety of lettuces at an early stage of growth while the leaves are small and close to the ground.
This has presented challenges unmet by mechanical harvesters and consequently all young leafy vegetables has been largely by hand.
One problem in mechanically harvesting leafy vegetables is that the plants are very small when harvested. This means that the leafy vegetables must be grown in rows or beds which are prepared to be as flat as possible. The widths of the beds are also dimensionally controlled as much as possible. A typical bed is either 40 inches or 42 inches wide, as measured from the center of furrows on either side of the bed. Separating each of the beds are furrows which allow the passage of the wheels of farm equipment used to cultivate, plant, maintain, and harvest the leafy vegetables. With such small plants, a harvester must be able to maintain the cutting mechanism approximately ¼ inch off the surface of the bed.
Another problem is that the leafy vegetables are very tender. They are easily bruised by conventional harvesters. Bruised or damaged leafy vegetables are not saleable and must be discarded, reducing yield.
One conventional harvester uses a sickle cutter formed at the bottom of a double belted conveyer system. The bottom belt is made of a metal mesh and the top conveyer is made of a flexible material with “fingers” formed in layers on the flexible belt. The fingers hold the cut leafy vegetables in contact with the lower conveyer as the cut produce is conveyed up the conveyer to the discharge area. This is necessary so that wind, for example, does not blow the cut leafy vegetables off of the conveyer.
This arrangement has several deficiencies. First, the fingers, while flexible, tend to damage or bruise the delicate leafy vegetables, thereby reducing yield. The fingers tend to break and the entire conveyer must be removed and replaced with a new or repaired one. This is both expensive and time consuming. Also, the presence of the upper fingered belt makes it difficult to inspect and clean the area between the two conveyer belts.
Another problem occurs because of the trend towards the use of double size rows or beds in addition to standard size beds. The width of these beds is 80 inches, or double the width of a conventional 40 inch bed. Eighty inch beds eliminate every other furrow in comparison with a field of 40 inch beds. This increases the area of cultivatable land, and hence yield, up to 50% to 80%. No known harvester is presently available which can harvester 40 inch, 42 inch and 80 inch beds.
It is very important that when the “spring mix” is ultimately shipped to customers and consumers that it be clean and completely free of sticks, weeds, or other debris. Also, any bruised or damaged leafs must be eliminated. Cotyledon, the poorly formed embryonic underleaves, must also be eliminated. When harvesting leafy vegetables manually this can largely be done when the plants are selected and cut by the field worker. Existing harvesting techniques introduce undesirable amounts of debris and unwanted materials with the harvested leafy vegetables.
SUMMARY OF THE INVENTION
In accordance with the present invention, a harvester for leafy vegetables is provided which is capable of use with beds of 40 and 42 inches, as well as double size rows of 80 inches. This is accomplished by separating the two front wheels and the two back wheels by somewhat more than the distance of an 80 inch bed, so each pair of wheels run in every other furrow. A conveyer/cutter assembly is designed to exceed the width of a single row, i.e, 36 inches. The conveyer/cutter assembly is located on one side of the centerline of the harvester, the centerline running lengthwise midway between the front pair of wheels and the back pair of wheels. The operator station and engine are located on the other side of he centerline.
Cutting 40 or 42 inch beds is done conventionally, with the harvester cutting a full bed as the harvester passes along each bed. To cut an 80 inch bed, the harvester makes a first pass in one direction along a bed, cutting half the width of the bed. The harvester then makes a second pass in the opposite direction to cut the remaining half width.
In accordance with the present invention, damage to the freshly cut leafy vegetables is reduced by eliminating the upper conveyer belt. A single conveyer belt is used with periodic cleats which hold the cut leafy vegetables as they are conveyed upwardly to the discharge area. Yield is increased because there are no fingers to damage the freshly cut leafy vegetables. To keep the wind from blowing the leafy vegetables away an enclosure, such as a hood, is provided which surrounds the conveyer belt. The hood is hingedly mounted to permit easy access to the conveyer belt.
A reel is mounted at the bottom of the conveyer belt. It is provided with brushes or fingers. The reel serves two purposes. The first is to engage the plants being cut to provide a slight amount of pressure against them as they engage the cutter assembly. This results in a better and cleaner cut. Secondly, they “brush” the cut leafy vegetables onto the conveyer for transportation up to the discharge area.
In accordance with another aspect of the present invention, an improved method of harvesting and processing leafy vegetables is described. After the harvester of the present invention cuts the leafy vegetables, the produce is kept and transported in baskets, often referred to as “totes.” Before the harvested leafy vegetables are washed, dried, mixed, weighed and packaged in a processing facility, they are transported to a shaker/cleaner, typically towed near the field where harvesting takes place. The totes are manually unloaded onto an input conveyer.
They are then discharged onto a conveyer made of a metal mesh. The mesh allows debris and other unwanted material to fall therethrough. To increase the fall-out of unwanted debris, the mesh is shaken or oscillated as it carries the leafy vegetable harvest to a discharge chute. The shaker/cleaner is adapted to have workers on either side of the mesh conveyer to manually pick out debris and unwanted materials.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a prospective view of the preferred embodiment of a leafy vegetable harvester of the present invention.
FIG. 2 is a side view of the harvester of FIG. 1 .
FIG. 3 is a front view of the harvester of FIG. 1 .
FIG. 4 is a top view of the harvester of FIG. 1 .
FIG. 5 is an isolated view, partially exploded, of the conveying system of the harvester of FIG. 1 .
FIG. 6 is an isolated view of the conveying system of FIG. 5 .
FIG. 7 is a detail of the cutter and cutter drive mechanism of FIG. 6 .
FIG. 8 is a prospective view of an alternative leafy vegetable harvester of the present invention.
FIG. 9 is an isolated view of the cutter/conveying system of the harvester of FIG. 8 .
FIG. 10 is a prospective view of the shaker/cleaner used in the improved leafy vegetable harvesting method of the invention.
FIG. 11 is a top view of the shaker/cleaner of FIG. 10 .
FIG. 12 is a front view of the shaker/cleaner of FIG. 10 .
FIG. 13 is a rear view of the shaker/cleaner of FIG. 10 .
FIG. 14 is a side view of he shaker/cleaner of FIG. 10 .
FIG. 15 is a detailed cross-sectional view of the mechanism for oscillating the mesh conveyer of the shaker/cleaner of FIG. 10 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1 - 4 illustrate the preferred embodiment of a leafy vegetable harvester 10 in accordance with the present invention. Harvester 10 has a frame or chassis 12 which supports the various components of the harvester. The back part of the harvester has a storage area 14 which includes a platform 16 and railing 18 surrounding the platform 16 .
A lower part of the chassis 20 supports an engine 22 , an operator's station 24 and an inclined conveying system 26 . Mounted at the lower end of the conveyer 26 is a cutting assembly 28 . At the top of the conveyer is a discharge portion 30 . Immediately underneath the discharge 30 is a receiving platform 32 where empty totes are placed and then filled by the discharged harvested leafy vegetables. An extended portion 34 (FIG. 4) of the receiving platform is used to place the next tote to be filled.
When a tote is filled up with cut leafy vegetables, the next tote is slid under the discharge 30 . The filled tote is stored on the platform 16 , as are the empty totes to be filled. Typically one worker stands on a small platform 36 to exchange the totes as each is filled and another worker brings the first worker empty totes and places filled totes on platform 16 . The storage area can hold as many totes as desired, with 100 , stacked five high, being a desirable number.
A.third worker sits at a seat 38 and operates the harvester. The steering wheel 40 and a control console 42 form a part of the operator's station.
As is conventional the front pair of wheels 44 are larger than the back wheels 46 . The back wheels are the steering wheels. They are larger because they bear most of the weight of the harvester. The front wheels are the drive wheels. The spacing of each pair of wheels 44 and 46 exceeds the double width bed size of 80 inches. The center of each tire should be approximately aligned with the center of the furrow. This results in a spacing, as measured from the middle of each pair of wheels, of 86 inches.
As best seen by reference to FIGS. 3 and 4, substantially all of the conveyer 26 and cutting mechanism 28 is located on one side of the harvester's centerline 48 . The operator's station 24 and engine 22 are located on the other side of centerline 48 .
The cutter mechanism 28 is a reciprocating sickle type cutter, with relatively small teeth spaced relatively close together, in the range of about 1 inch, to be able to cut the small leafy vegetable plants. The cutting mechanism from an ordinary hedge trimmer has been found to work satisfactorily.
The width of the cutter mechanism should exceed the width of a standard 42 inch wide bed. A cutter blade of 38 inches is preferred. This allows the harvester to cut leafy vegetables of either the standard 40 inch or 42 inch width bed.
As explained above, harvester 10 can also be used to cut a double size bed of 80 inches. Since the distance between the front pair of wheels 44 and the back pair of wheels 46 is greater than 80 inches the harvester can travel down a field with either standard width or double width rows. If the bed is a double width bed of 80 inches, the harvester 10 first harvests one half of the bed traveling in one direction, and then the other half of the bed, traveling the other direction.
Locating the conveyer and cutting mechanism on one side of the harvester's centerline, and the driver's station and engine on the other, also results in the harvester's weight being relatively equally distributed.
Details of the conveyer system 26 are additionally shown in greater detail in FIGS. 5 - 7 . Mounted to the lower end of the conveyer 26 is a reel 50 which includes a rotatable shaft 52 . Radially extending from the shaft 52 are a plurality of slats or brushes 54 . Each may be a single strip of flexible material, or each may be formed by a plurality of flexible fingers, from 1 to 2 inches in width, with 1½ inch being optimal. The material forming the fingers is white Nitrile webbing.
The fingers of the reel engage the plants to be cut and bring them in contact with the sickle cutter. This facilitates the cutting action of the sickle cutter, insuring a better cut of the leafy vegetables. The brushes or fingers 54 of the reel 50 also act to convey the cut leafy vegetables onto conveyer belt 56 . The belt 56 preferably is a stainless steel mesh with ½ inch by ½ inch openings.
The cut leafy vegetables are held in place as the conveyer 56 transports the produce upwardly towards the discharge portion 30 by means of a plurality of cleats secured, such as by welding, transversely to the mesh conveyer belt 56 . Since no pressure is applied to the delicate produce, less bruising and damage occurs than with the double belted conveyer approach.
To keep the leafy vegetables from being blown off of the conveyer 56 an enclosure such as a hood 60 surrounds the conveyer 56 . The hood 60 has a fixed portion 62 which is connected to the lower portion 64 by a hinge 66 so that the lower portion 64 can swing upwardly to allow inspection and cleaning of the conveyer 60 .
The height of the cutter assembly 28 is set by a gauge roller 68 . A control mechanism 70 (FIG. 5) controls the position of gauge roller 68 .
As is well known, a hydrostat drive system is used, which includes a variable speed hydraulic transmission for driving and controlling the wheel speed. The steering, operation of the conveyer 56 , and rotation of reel 50 is done in conventional fashion, hydraulicly. Engine 22 drives an auxiliary pump (not shown) for providing the hydraulic power necessary. Standard hydraulic motors are used throughout.
The entire conveyer system 26 can be raised and lowered. A hydraulic piston (FIG. 2) is used to raise and lower the conveyer 26 . A 40 horsepower John Deere diesel engine 22 is suitable for the engine 22 .
As explained, conveyer 56 is powered by a hydraulic motor which is coupled to an upper rotatable shaft 74 . The lower end of conveyer 56 passes around a lower shaft 76 .
FIG. 7 is a detailed view of one gearing arrangement 80 to convert rotary power of a hydraulic motor for driving the cutter mechanism 28 , which requires a reciprocating action between the upper and lower sickle bars. Alternatively, the drive mechanism from a standard hedge trimmer can be used, such as a Shindowia brand drive blade, although the reciprocating speed needs to be increased for the best cutting action. A reciprocating rate of 450-600 strokes per minute has been found to be effective.
FIGS. 8 and 9 show an alternative embodiment of the improved harvester 100 of the present invention, capable of use with either single or double size beds. Harvester 100 is similar to the preferred harvester 10 of FIGS. 1 - 7 , with the major difference being the construction of the conveyer means 26 . Like elements are labeled with the same reference numbers in FIGS. 8 and 9.
Here the conveyer means comprises two conveyer belts, a lower belt 102 and an upper belt 104 . The lower conveyer 102 conveys the cut leafy vegetables upwardly to a discharge chute 106 . The belt 102 is a conventional alloy steel wire conveyer. The conveyer circulates in a clockwise direction as viewed in FIGS. 8 and 9.
The upper conveyor belt 104 circulates in the opposite direction, counter-clockwise, and at the same speed as lower belt 102 . If there is a speed differential, damage to the produce occurs. Belt 104 preferably is made of flexible 3-ply poly 90 belting. Attached to the belt 104 , for example by glue, are a plurality of flaps or fingers 106 , shown figuratively in FIG. 8 . The flaps are preferably made of 2-ply poly white Nitrile. The width of each finger is desirably about 2½ inches.
FIGS. 10 - 15 illustrate a shaker/cleaner apparatus 200 which is utilized in the improved harvesting and cleaning method of the present invention. Once the totes on the harvester are filled, they are transported to the shaker/cleaner 200 , which is supported by and is transported by a trailer 202 . The shaker/cleaner is stationary when in use.
An input conveyer 204 is used to transport the cut leafy vegetables to the mesh conveyer 206 . The conveyer 204 is inclined upwardly so that cut leafy vegetables can more easily be dumped onto the conveyer 206 by workers. The conveyer 204 has affixed to it a plurality of cleats 208 and side walls 210 to aid in conveying the produce upwardly.
The two conveyers are supported by a frame structure 212 mounted to a platform 214 supported by the trailer 202 . Platform 214 provides two surfaces 216 and 218 for workers to stand, adjacent to the mesh conveyer 206 , for the purpose to be explained.
Cut leafy vegetables discharged from the input conveyer 204 are transported by the mesh conveyer 206 to a discharge portion 220 . Empty totes or baskets are placed on a receiving platform 222 for receiving the leafy vegetables exiting the mesh conveyer 206 .
Harvested leafy vegetables typically have a certain amount of debris, damaged leaves, and unwanted materials associated with it. The mesh conveyer 206 has a chain-type mesh surface such as galvanized flat wire belting with openings approximately one inch by one inch to allow such unwanted materials to fall through the conveyer. To increase the amount of unwanted material which is passed out through mesh conveyer 206 , the mesh conveyer is shaken or oscillated as it circulates toward the discharge portion.
This is accomplished by providing a plurality of shafts underneath and supporting mesh conveyer 206 . The shafts 24 are mounted off-center as will be explained. When rotated they “wobble”, thus imparting an oscillating motion to the conveyer 206 to shake out unwanted material.
A detailed cross-sectional view of one of the bearings 226 for one of the shafts 224 is shown in FIG. 15 . The bearing has a cross-sectional dimension greater than the shaft 224 , with an outside diameter of four inches and an inside diameter of 2.165 inches. A bushing 228 is inserted within the race 230 of the bearing. The bushing as drilled in it a hole having a dimension of that of the shaft 224 . The hole is provided off center of the bushing. Thus when the drive mechanism (not shown) rotates the shaft 224 , the rotation of the shaft 224 will rotate off center, causing the shaft to go up and down. This in turn, causes the mesh 226 , which travels across the surface of the bearings to go up and down.
Workers standing on either side of the conveyer 206 can remove unwanted or damaged produce which does not fall through the mesh. Debris which falls through the mesh is diverted down and away by a plate 232 (FIG. 10) affixed at a 45 degree angle below conveyer 206 .
A gasoline engine (not shown) is mounted below input conveyer 204 to provide power to a hydraulic pump (not shown) to motors for driving the two conveyers, in a conventional fashion. Each of the shafts 224 is driven by a single hydraulic motor. | A harvester for harvesting leafy vegetables, lettuce and the like which are very delicate and which are grown in precisely configured beds of either a regular or single width (40 inches or 42 inches) or a double width (80 inches). A single conveyer/cutter assembly is located on one side of the harvester centerline and has a width somewhat exceeding the width of a single width bed. The wheels on each side are separated by somewhat more than the width of a double bed. The driver and engine is located on the other side of the centerline. Such a harvester can cut single width beds, or can cut double width beds by making a first pass in one direction and a second pass in the other direction. The single conveyer/cutter reduces the amount of debris and unwanted material from the harvested leafy vegetables. | Briefly outline the background technology and the problem the invention aims to solve. | [
"This is a divisional of application Ser.",
"No. 08/819,375, filed Mar. 17, 1997.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present invention relates to a harvester for leafy vegetables and a process for harvesting leafy vegetables.",
"Description of the Related Art Harvesting young or early growth leafy vegetables presents particular problems not found when harvesting other vegetables.",
"By “leafy vegetables”",
"it is meant that family of specialty lettuces and other leafy greens which, when mixed together for sale and consumption are sometimes referred to as “spring mix,” “mixed greens,” or “baby greens.”",
"For example, this includes lettuces, such as green romaine, red romaine, sierra, lola rosa, tango, green leaf, red leaf, little gem, red butter, read oak, red perella and green perella.",
"It also includes greens such as arugula, maxine, red mustard, green mustard, spinach, tat tai, red chard and red russian kale.",
"If such leafy vegetables are grown under certain conditions, the harvested produce can be certified as organically grown.",
"Harvesters are known for cutting some vegetables such as spinach, cabbage, watercress and the like.",
"Recently, consumer demand has required harvesting a variety of lettuces at an early stage of growth while the leaves are small and close to the ground.",
"This has presented challenges unmet by mechanical harvesters and consequently all young leafy vegetables has been largely by hand.",
"One problem in mechanically harvesting leafy vegetables is that the plants are very small when harvested.",
"This means that the leafy vegetables must be grown in rows or beds which are prepared to be as flat as possible.",
"The widths of the beds are also dimensionally controlled as much as possible.",
"A typical bed is either 40 inches or 42 inches wide, as measured from the center of furrows on either side of the bed.",
"Separating each of the beds are furrows which allow the passage of the wheels of farm equipment used to cultivate, plant, maintain, and harvest the leafy vegetables.",
"With such small plants, a harvester must be able to maintain the cutting mechanism approximately ¼ inch off the surface of the bed.",
"Another problem is that the leafy vegetables are very tender.",
"They are easily bruised by conventional harvesters.",
"Bruised or damaged leafy vegetables are not saleable and must be discarded, reducing yield.",
"One conventional harvester uses a sickle cutter formed at the bottom of a double belted conveyer system.",
"The bottom belt is made of a metal mesh and the top conveyer is made of a flexible material with “fingers”",
"formed in layers on the flexible belt.",
"The fingers hold the cut leafy vegetables in contact with the lower conveyer as the cut produce is conveyed up the conveyer to the discharge area.",
"This is necessary so that wind, for example, does not blow the cut leafy vegetables off of the conveyer.",
"This arrangement has several deficiencies.",
"First, the fingers, while flexible, tend to damage or bruise the delicate leafy vegetables, thereby reducing yield.",
"The fingers tend to break and the entire conveyer must be removed and replaced with a new or repaired one.",
"This is both expensive and time consuming.",
"Also, the presence of the upper fingered belt makes it difficult to inspect and clean the area between the two conveyer belts.",
"Another problem occurs because of the trend towards the use of double size rows or beds in addition to standard size beds.",
"The width of these beds is 80 inches, or double the width of a conventional 40 inch bed.",
"Eighty inch beds eliminate every other furrow in comparison with a field of 40 inch beds.",
"This increases the area of cultivatable land, and hence yield, up to 50% to 80%.",
"No known harvester is presently available which can harvester 40 inch, 42 inch and 80 inch beds.",
"It is very important that when the “spring mix”",
"is ultimately shipped to customers and consumers that it be clean and completely free of sticks, weeds, or other debris.",
"Also, any bruised or damaged leafs must be eliminated.",
"Cotyledon, the poorly formed embryonic underleaves, must also be eliminated.",
"When harvesting leafy vegetables manually this can largely be done when the plants are selected and cut by the field worker.",
"Existing harvesting techniques introduce undesirable amounts of debris and unwanted materials with the harvested leafy vegetables.",
"SUMMARY OF THE INVENTION In accordance with the present invention, a harvester for leafy vegetables is provided which is capable of use with beds of 40 and 42 inches, as well as double size rows of 80 inches.",
"This is accomplished by separating the two front wheels and the two back wheels by somewhat more than the distance of an 80 inch bed, so each pair of wheels run in every other furrow.",
"A conveyer/cutter assembly is designed to exceed the width of a single row, i.e, 36 inches.",
"The conveyer/cutter assembly is located on one side of the centerline of the harvester, the centerline running lengthwise midway between the front pair of wheels and the back pair of wheels.",
"The operator station and engine are located on the other side of he centerline.",
"Cutting 40 or 42 inch beds is done conventionally, with the harvester cutting a full bed as the harvester passes along each bed.",
"To cut an 80 inch bed, the harvester makes a first pass in one direction along a bed, cutting half the width of the bed.",
"The harvester then makes a second pass in the opposite direction to cut the remaining half width.",
"In accordance with the present invention, damage to the freshly cut leafy vegetables is reduced by eliminating the upper conveyer belt.",
"A single conveyer belt is used with periodic cleats which hold the cut leafy vegetables as they are conveyed upwardly to the discharge area.",
"Yield is increased because there are no fingers to damage the freshly cut leafy vegetables.",
"To keep the wind from blowing the leafy vegetables away an enclosure, such as a hood, is provided which surrounds the conveyer belt.",
"The hood is hingedly mounted to permit easy access to the conveyer belt.",
"A reel is mounted at the bottom of the conveyer belt.",
"It is provided with brushes or fingers.",
"The reel serves two purposes.",
"The first is to engage the plants being cut to provide a slight amount of pressure against them as they engage the cutter assembly.",
"This results in a better and cleaner cut.",
"Secondly, they “brush”",
"the cut leafy vegetables onto the conveyer for transportation up to the discharge area.",
"In accordance with another aspect of the present invention, an improved method of harvesting and processing leafy vegetables is described.",
"After the harvester of the present invention cuts the leafy vegetables, the produce is kept and transported in baskets, often referred to as “totes.”",
"Before the harvested leafy vegetables are washed, dried, mixed, weighed and packaged in a processing facility, they are transported to a shaker/cleaner, typically towed near the field where harvesting takes place.",
"The totes are manually unloaded onto an input conveyer.",
"They are then discharged onto a conveyer made of a metal mesh.",
"The mesh allows debris and other unwanted material to fall therethrough.",
"To increase the fall-out of unwanted debris, the mesh is shaken or oscillated as it carries the leafy vegetable harvest to a discharge chute.",
"The shaker/cleaner is adapted to have workers on either side of the mesh conveyer to manually pick out debris and unwanted materials.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a prospective view of the preferred embodiment of a leafy vegetable harvester of the present invention.",
"FIG. 2 is a side view of the harvester of FIG. 1 .",
"FIG. 3 is a front view of the harvester of FIG. 1 .",
"FIG. 4 is a top view of the harvester of FIG. 1 .",
"FIG. 5 is an isolated view, partially exploded, of the conveying system of the harvester of FIG. 1 .",
"FIG. 6 is an isolated view of the conveying system of FIG. 5 .",
"FIG. 7 is a detail of the cutter and cutter drive mechanism of FIG. 6 .",
"FIG. 8 is a prospective view of an alternative leafy vegetable harvester of the present invention.",
"FIG. 9 is an isolated view of the cutter/conveying system of the harvester of FIG. 8 .",
"FIG. 10 is a prospective view of the shaker/cleaner used in the improved leafy vegetable harvesting method of the invention.",
"FIG. 11 is a top view of the shaker/cleaner of FIG. 10 .",
"FIG. 12 is a front view of the shaker/cleaner of FIG. 10 .",
"FIG. 13 is a rear view of the shaker/cleaner of FIG. 10 .",
"FIG. 14 is a side view of he shaker/cleaner of FIG. 10 .",
"FIG. 15 is a detailed cross-sectional view of the mechanism for oscillating the mesh conveyer of the shaker/cleaner of FIG. 10 .",
"DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 - 4 illustrate the preferred embodiment of a leafy vegetable harvester 10 in accordance with the present invention.",
"Harvester 10 has a frame or chassis 12 which supports the various components of the harvester.",
"The back part of the harvester has a storage area 14 which includes a platform 16 and railing 18 surrounding the platform 16 .",
"A lower part of the chassis 20 supports an engine 22 , an operator's station 24 and an inclined conveying system 26 .",
"Mounted at the lower end of the conveyer 26 is a cutting assembly 28 .",
"At the top of the conveyer is a discharge portion 30 .",
"Immediately underneath the discharge 30 is a receiving platform 32 where empty totes are placed and then filled by the discharged harvested leafy vegetables.",
"An extended portion 34 (FIG.",
"4) of the receiving platform is used to place the next tote to be filled.",
"When a tote is filled up with cut leafy vegetables, the next tote is slid under the discharge 30 .",
"The filled tote is stored on the platform 16 , as are the empty totes to be filled.",
"Typically one worker stands on a small platform 36 to exchange the totes as each is filled and another worker brings the first worker empty totes and places filled totes on platform 16 .",
"The storage area can hold as many totes as desired, with 100 , stacked five high, being a desirable number.",
"A.third worker sits at a seat 38 and operates the harvester.",
"The steering wheel 40 and a control console 42 form a part of the operator's station.",
"As is conventional the front pair of wheels 44 are larger than the back wheels 46 .",
"The back wheels are the steering wheels.",
"They are larger because they bear most of the weight of the harvester.",
"The front wheels are the drive wheels.",
"The spacing of each pair of wheels 44 and 46 exceeds the double width bed size of 80 inches.",
"The center of each tire should be approximately aligned with the center of the furrow.",
"This results in a spacing, as measured from the middle of each pair of wheels, of 86 inches.",
"As best seen by reference to FIGS. 3 and 4, substantially all of the conveyer 26 and cutting mechanism 28 is located on one side of the harvester's centerline 48 .",
"The operator's station 24 and engine 22 are located on the other side of centerline 48 .",
"The cutter mechanism 28 is a reciprocating sickle type cutter, with relatively small teeth spaced relatively close together, in the range of about 1 inch, to be able to cut the small leafy vegetable plants.",
"The cutting mechanism from an ordinary hedge trimmer has been found to work satisfactorily.",
"The width of the cutter mechanism should exceed the width of a standard 42 inch wide bed.",
"A cutter blade of 38 inches is preferred.",
"This allows the harvester to cut leafy vegetables of either the standard 40 inch or 42 inch width bed.",
"As explained above, harvester 10 can also be used to cut a double size bed of 80 inches.",
"Since the distance between the front pair of wheels 44 and the back pair of wheels 46 is greater than 80 inches the harvester can travel down a field with either standard width or double width rows.",
"If the bed is a double width bed of 80 inches, the harvester 10 first harvests one half of the bed traveling in one direction, and then the other half of the bed, traveling the other direction.",
"Locating the conveyer and cutting mechanism on one side of the harvester's centerline, and the driver's station and engine on the other, also results in the harvester's weight being relatively equally distributed.",
"Details of the conveyer system 26 are additionally shown in greater detail in FIGS. 5 - 7 .",
"Mounted to the lower end of the conveyer 26 is a reel 50 which includes a rotatable shaft 52 .",
"Radially extending from the shaft 52 are a plurality of slats or brushes 54 .",
"Each may be a single strip of flexible material, or each may be formed by a plurality of flexible fingers, from 1 to 2 inches in width, with 1½ inch being optimal.",
"The material forming the fingers is white Nitrile webbing.",
"The fingers of the reel engage the plants to be cut and bring them in contact with the sickle cutter.",
"This facilitates the cutting action of the sickle cutter, insuring a better cut of the leafy vegetables.",
"The brushes or fingers 54 of the reel 50 also act to convey the cut leafy vegetables onto conveyer belt 56 .",
"The belt 56 preferably is a stainless steel mesh with ½ inch by ½ inch openings.",
"The cut leafy vegetables are held in place as the conveyer 56 transports the produce upwardly towards the discharge portion 30 by means of a plurality of cleats secured, such as by welding, transversely to the mesh conveyer belt 56 .",
"Since no pressure is applied to the delicate produce, less bruising and damage occurs than with the double belted conveyer approach.",
"To keep the leafy vegetables from being blown off of the conveyer 56 an enclosure such as a hood 60 surrounds the conveyer 56 .",
"The hood 60 has a fixed portion 62 which is connected to the lower portion 64 by a hinge 66 so that the lower portion 64 can swing upwardly to allow inspection and cleaning of the conveyer 60 .",
"The height of the cutter assembly 28 is set by a gauge roller 68 .",
"A control mechanism 70 (FIG.",
"5) controls the position of gauge roller 68 .",
"As is well known, a hydrostat drive system is used, which includes a variable speed hydraulic transmission for driving and controlling the wheel speed.",
"The steering, operation of the conveyer 56 , and rotation of reel 50 is done in conventional fashion, hydraulicly.",
"Engine 22 drives an auxiliary pump (not shown) for providing the hydraulic power necessary.",
"Standard hydraulic motors are used throughout.",
"The entire conveyer system 26 can be raised and lowered.",
"A hydraulic piston (FIG.",
"2) is used to raise and lower the conveyer 26 .",
"A 40 horsepower John Deere diesel engine 22 is suitable for the engine 22 .",
"As explained, conveyer 56 is powered by a hydraulic motor which is coupled to an upper rotatable shaft 74 .",
"The lower end of conveyer 56 passes around a lower shaft 76 .",
"FIG. 7 is a detailed view of one gearing arrangement 80 to convert rotary power of a hydraulic motor for driving the cutter mechanism 28 , which requires a reciprocating action between the upper and lower sickle bars.",
"Alternatively, the drive mechanism from a standard hedge trimmer can be used, such as a Shindowia brand drive blade, although the reciprocating speed needs to be increased for the best cutting action.",
"A reciprocating rate of 450-600 strokes per minute has been found to be effective.",
"FIGS. 8 and 9 show an alternative embodiment of the improved harvester 100 of the present invention, capable of use with either single or double size beds.",
"Harvester 100 is similar to the preferred harvester 10 of FIGS. 1 - 7 , with the major difference being the construction of the conveyer means 26 .",
"Like elements are labeled with the same reference numbers in FIGS. 8 and 9.",
"Here the conveyer means comprises two conveyer belts, a lower belt 102 and an upper belt 104 .",
"The lower conveyer 102 conveys the cut leafy vegetables upwardly to a discharge chute 106 .",
"The belt 102 is a conventional alloy steel wire conveyer.",
"The conveyer circulates in a clockwise direction as viewed in FIGS. 8 and 9.",
"The upper conveyor belt 104 circulates in the opposite direction, counter-clockwise, and at the same speed as lower belt 102 .",
"If there is a speed differential, damage to the produce occurs.",
"Belt 104 preferably is made of flexible 3-ply poly 90 belting.",
"Attached to the belt 104 , for example by glue, are a plurality of flaps or fingers 106 , shown figuratively in FIG. 8 .",
"The flaps are preferably made of 2-ply poly white Nitrile.",
"The width of each finger is desirably about 2½ inches.",
"FIGS. 10 - 15 illustrate a shaker/cleaner apparatus 200 which is utilized in the improved harvesting and cleaning method of the present invention.",
"Once the totes on the harvester are filled, they are transported to the shaker/cleaner 200 , which is supported by and is transported by a trailer 202 .",
"The shaker/cleaner is stationary when in use.",
"An input conveyer 204 is used to transport the cut leafy vegetables to the mesh conveyer 206 .",
"The conveyer 204 is inclined upwardly so that cut leafy vegetables can more easily be dumped onto the conveyer 206 by workers.",
"The conveyer 204 has affixed to it a plurality of cleats 208 and side walls 210 to aid in conveying the produce upwardly.",
"The two conveyers are supported by a frame structure 212 mounted to a platform 214 supported by the trailer 202 .",
"Platform 214 provides two surfaces 216 and 218 for workers to stand, adjacent to the mesh conveyer 206 , for the purpose to be explained.",
"Cut leafy vegetables discharged from the input conveyer 204 are transported by the mesh conveyer 206 to a discharge portion 220 .",
"Empty totes or baskets are placed on a receiving platform 222 for receiving the leafy vegetables exiting the mesh conveyer 206 .",
"Harvested leafy vegetables typically have a certain amount of debris, damaged leaves, and unwanted materials associated with it.",
"The mesh conveyer 206 has a chain-type mesh surface such as galvanized flat wire belting with openings approximately one inch by one inch to allow such unwanted materials to fall through the conveyer.",
"To increase the amount of unwanted material which is passed out through mesh conveyer 206 , the mesh conveyer is shaken or oscillated as it circulates toward the discharge portion.",
"This is accomplished by providing a plurality of shafts underneath and supporting mesh conveyer 206 .",
"The shafts 24 are mounted off-center as will be explained.",
"When rotated they “wobble”, thus imparting an oscillating motion to the conveyer 206 to shake out unwanted material.",
"A detailed cross-sectional view of one of the bearings 226 for one of the shafts 224 is shown in FIG. 15 .",
"The bearing has a cross-sectional dimension greater than the shaft 224 , with an outside diameter of four inches and an inside diameter of 2.165 inches.",
"A bushing 228 is inserted within the race 230 of the bearing.",
"The bushing as drilled in it a hole having a dimension of that of the shaft 224 .",
"The hole is provided off center of the bushing.",
"Thus when the drive mechanism (not shown) rotates the shaft 224 , the rotation of the shaft 224 will rotate off center, causing the shaft to go up and down.",
"This in turn, causes the mesh 226 , which travels across the surface of the bearings to go up and down.",
"Workers standing on either side of the conveyer 206 can remove unwanted or damaged produce which does not fall through the mesh.",
"Debris which falls through the mesh is diverted down and away by a plate 232 (FIG.",
"10) affixed at a 45 degree angle below conveyer 206 .",
"A gasoline engine (not shown) is mounted below input conveyer 204 to provide power to a hydraulic pump (not shown) to motors for driving the two conveyers, in a conventional fashion.",
"Each of the shafts 224 is driven by a single hydraulic motor."
] |
BACKGROUND
[0001] The growth and adoption of wide-area data networks such as the Internet have enabled merchants to offer a number of new services to consumers. These services often center around data manipulation and storage, and can be provided to a large number of consumers without significant setup or operational expense. As a result, merchants often provide these services to consumers gratis, and look to alternate revenue sources such as advertising and data aggregation (that is, collection and sale of data about consumers' preferences and habits) in hopes of creating a viable business. Unfortunately, operating a service business in this manner engenders a feeling of entitlement to future free service among consumers. Consequently, merchants find it difficult to provide new services which do require significant investment or operating capital, because consumers are reluctant to try a new service that is not free, yet many services cannot economically be provided for the amount of money that can be earned by advertising or data aggregation.
[0002] Merchants have commonly addressed this problem by simply offering the new, expensive-to-provide service gratis (and at a financial loss) during an introductory period, in the hope that consumers will find the service valuable or indispensable and continue to use it when the introductory period terminates and the service must be paid for. However, this all-or-nothing approach does not work well given consumers' feelings of entitlement to free services; even if the new service is convenient or useful, a consumer faced with the choice to “pay up” or get out will often grumble and stop using the service, and may become annoyed enough to abandon the merchant's other services as well.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] Embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.”
[0004] FIG. 1 depicts an overview of the components that may be involved in one or more embodiments of the invention.
[0005] FIG. 2 depicts an embodiment of the invention wherein a customer who uses the merchant's system to receive Y facsimile pages earns credit to use the merchant's system to transmit X facsimile pages.
[0006] FIG. 3 depicts a possible interaction between a customer and an automated server, in a service provided through another embodiment of the invention.
DETAILED DESCRIPTION
[0007] In the information-services realm, and particularly in the realm of communication services, a single performance of a service is often of very small value, yet the ability to obtain that service at any time is important and valuable. This disparity is reflected in the pricing structure for Internet services, for example. Currently, most businesses charge a fee for generalized Internet access (hourly, or more commonly, monthly) but do not impose any extra charge for amount of data transferred, number of websites visited, or number of electronic mail messages sent or received, although it would be technologically feasible to do so.
[0008] A further economic pressure that favors pay-for-availability over pay-per-use pricing is the high (relative) transaction cost associated with small monetary value transactions. As previously noted, the value of receiving a single performance of a service is often very small. However, there are no viable, widely-accepted micropayment systems that would support a pay-per-use pricing scheme for very small transaction amounts. There is simply no efficient way to sell a service for a fraction of a cent, or even for a few cents—all commonly-used payment methods have a transaction cost in excess of that amount.
[0009] In one embodiment of the invention, the merchant offers a customer credit toward one service when the customer uses another service. (Note that the term “customer” as used herein includes persons or entities with which the merchant has an existing commercial relationship, as well as persons or entities with which the merchant is attempting to establish a new relationship.) The merchant can maintain an account of these credits, which obviates the problem of dealing in small monetary amounts (in current-dollar terms, the range between zero and a few tens of cents, for example). Furthermore, by maintaining such an account, the merchant can fine-tune the credit offered much more precisely than can a typical merchant of physical goods who operates a typical customer loyalty program. Different credit amounts, including fractional credits, can be given based on the behaviors the merchant wants to encourage or discourage. For example, if the merchant offered services A (which was inexpensive or free, and widely used) and B (which was relatively expensive to provide and not widely used), it could encourage users to try B by offering a credit toward B each time a customer used A. However, once a particular customer had begun to use B regularly, the merchant could reduce the credit earned by using A, or transition to a B-only credit plan, where a customer would earn credit for future performances of B by using B.
[0010] Embodiments of the invention are well-suited to providing a variety of somewhat specialized communication services. For general communication services such as telephone, pager or electronic mail service, the mere availability of the service may be so valuable that consumers are willing to enter into long- or indefinite-term, monthly service contracts even if they do not always use the full amount of service to which they are entitled. However, for more specialized services such as facsimile transmission and reception, voicemail, conference call management, or oral recitation of textual data by a machine, a customer might be unwilling to enter a monthly contract when it is uncertain whether he will use the service at all in a particular month. Such services could be excellent candidates for pay-per-use sales strategies, but for reasons already discussed, it may not be possible to sell them in that manner. However, by applying the fractional credit accounting and incentive system disclosed, it becomes feasible to offer these services on a pay-per-use basis.
[0011] In an embodiment of the invention, a merchant such as j2 Global Communications of Hollywood, California, could offer facsimile reception and transmission services to its customers. Both services may require equipment and telephone lines to communicate with traditional facsimile equipment, so some capital expenditure may be necessary to provide those services. However, for sending facsimiles, outbound calling charges are also incurred, and so that service may be more expensive to provide. Thus, while it might be possible to provide facsimile reception services for free, the merchant could not provide transmission services without charging the customer. By applying an embodiment of the invention, the merchant could introduce a customer to the transmission service on a basis that is equivalent to a free introductory period (by giving a certain number of free transmission credits), and transition smoothly over time to a pay-per-use model by adjusting the credits given for the customer's use of sending and receiving services, ultimately arriving at the point where the customer would have confidence in the commercial relationship and would be willing to leave funds on account with the merchant to pay for future facsimile transmissions. In one specific application of an embodiment of the invention, a customer could earn credits to send a first number of outbound facsimile pages each time he receives a second number of inbound pages (both the first number and the second number being selectable by the merchant).
[0012] FIG. 1 depicts a number of elements that may be involved in one or more embodiments of the invention that involve providing fax and voicemail services. A merchant such as j2 Global Communications of Hollywood, Calif., may maintain one or more co-located data centers 120 a , 120 b , which may be located in diverse physical locations. Such diverse locations may be chosen to facilitate connections 111 a , 111 b to local telephone switching stations (not shown) that are part of a public switched telephone network (PSTN) 110 . Connections to local telephone switching stations may be desired because they allow the connected machines to be accessed through the PSTN by a local phone number (as opposed to a long-distance phone number). For example, if a co-located data center was placed in Tokyo, Japan, then the connected machines could place and receive inexpensive local phone calls to other phones in Tokyo, and less-expensive calls to and from other locations in Japan, as compared to such calls placed to or from a machine located in Geneva, Switzerland.
[0013] The co-located data centers may contain a number of server functions such as web server 121 , electronic mail (e-mail) server 122 , database server 123 , voice mail server 124 , and fax server 125 . Each function may be distributed among a number of physical machines, or a number of functions may be consolidated in one machine. The machines may be connected to a data communication network 126 , which allows them to communicate with each other and with a network routing and/or security device such as firewall 127 .
[0014] Each co-located data center may be able to communicate with other centers and/or with a central data center 150 through a variety of data networks, such as private data network 130 , virtual private network (VPN) 135 , and/or public data network 140 . The Internet is a well-known example of a public data network. Data transmitted over a private network are relatively secure against eavesdropping, but data transmitted over a public network such as the Internet may be exposed to third parties at many points. A VPN uses encryption to transmit data securely between two locations over either public or private data networks. Data are much less vulnerable to eavesdropping and modification while in transit across a VPN, so the computers using the VPN to communicate may not need to encrypt their data separately to protect it, although such encryption may provide additional security.
[0015] The merchant may operate a central data center 150 , containing server functions such as file server 151 , database server 152 , web server 153 , and email server 154 . Each server function may be distributed across a number of physical machines, or several server functions may be consolidated on a single physical machine. Each machine may be connected to a network 155 , which may provide access to private data networks 130 , VPNs 135 , and/or public data networks 140 through a network routing and/or security device such as firewall 156 .
[0016] The merchant's customers and other participants in an embodiment of the invention include fax machines 100 and customers who connect to the PSTN by means of a land line 101 or a cell phone 102 . Customers may interact with services provided by the merchant over a data network by means of computers 165 and 170 , which may be connected directly to a public data network 140 or to the network through an ISP 160 .
[0017] A specific example of the way in which facsimile reception could be provided may be explained with reference to FIG. 1 . A person who wished to transmit a facsimile to a customer could send it through PSTN 110 from his fax machine 100 to a fax server 125 located in one of the merchant's co-located data centers 120 a , 120 b . The fax server could convert the facsimile signal into one or more tag image file format (TIFF) files. These files could be assembled into an e-mail message and sent directly to an e-mail address of the customer by e-mail server 122 , where the customer's e-mail address could be obtained from database server 123 . For added security, the message could be encrypted prior to transmission by formatting the message as an S/MIME message. The customer could view the facsimile by retrieving the e-mail message, decrypting it if necessary, and displaying the TIFF file attachments.
[0018] Alternatively, to provide increased security without the difficulty of maintaining encryption key information for each customer, the merchant could arrange a VPN connection from a co-located data center to a data center serving a number of customers (not shown). The e-mail containing the TIFF attachments could be transmitted to the data center serving a number of customers securely over the VPN, and could later be retrieved from the second data center by the customer.
[0019] In yet another alternative, the merchant could transmit the e-mail message from its co-located data center 120 a securely by means of a VPN connection 135 to its own central data center 150 . Once received in the central data center, the TIFF attachments could be removed from the e-mail message, encrypted, and stored on database server 152 . Then, a notification e-mail message could be sent from the e-mail server 154 to the customer's computer 165 or 170 , informing the customer that a facsimile was available for viewing. The customer could connect to the merchant's web server 153 through public data network 140 , using a secure protocol such as HTTPS, authenticate himself to the web server through an appropriate challenge-and-response sequence, and download or display the facsimile from the database server 152 . This alternative may provide favorable security characteristics because the facsimile data are always protected by encryption while being transmitted from one place to another.
[0020] To provide facsimile transmission services, the merchant could accept electronic mail sent from a customer's computer ( 165 or 170 ) to the merchant's mail server 154 . This mail could contain a destination facsimile number and an attached document or image file to be transmitted. A server in the central data center could determine which co-located data center would provide the best connection to the destination facsimile machine, where the best connection may be selected on the basis of geographical proximity, low outbound calling cost, quality of connection, or other criteria. Once a “best” data center was selected, the email could be forwarded to the email server there, and then to a facsimile server. The facsimile server could convert the document or image file into a format suitable for transmission via facsimile, and then connect to the destination facsimile machine and send the converted document or image. After transmitting the document (or after attempting but failing to transmit the document), the facsimile server could transmit an email message notifying the customer of the result of the transmission.
[0021] In another embodiment of the invention, voice message communication services may be promoted. A customer could be provided with a telephone number that is connected to inbound call processing equipment. When a calling party dials the number, he would be asked to leave a voice message for the customer. When a message has been recorded, the customer could be notified through electronic mail or other means, and can retrieve the message at his leisure. Alternatively, the message could be converted into an electronic format and transmitted directly to a network address of the customer, without the need to store it on any of the merchant's systems.
[0022] In the context of facsimile and/or voice mail reception and facsimile transmission services, the embodiment of the invention depicted graphically in FIG. 2 would permit the merchant to offer to transmit X facsimile pages for a customer each time the customer receives Y voice mail messages or facsimile pages, where “X” and “Y” are non-negative numbers, and “X” need not be an integer. The merchant 201 would provide a telephone number 202 to the customer 203 , where the telephone number was connected to a device 206 maintained by the merchant that can record voice mail messages and/or receive facsimiles. The customer could give the telephone number to third parties 204 as the customer's own voice mail or facsimile number. When a voice mail message or facsimile is sent to that telephone number 205 , the merchant's device 206 receives it and may retransmit it to the customer, store it locally, or forward it to a central repository for later retrieval by the customer. In addition, the device 206 may notify the customer that the message or facsimile has been received. When Y messages and/or pages have been received, the customer's account 207 is credited so that the customer can send X facsimile pages by using the merchant's equipment, according to the method described above. After transmission, the merchant could deduct the number of pages sent from the customer's credit balance.
[0023] Another communication service that is suitable for promotion though this invention is conference call management. A merchant could provide a telephone number to a customer, where the telephone number is connected to equipment that can receive multiple callers and connect them in a conference-call fashion. The telephone number could be dedicated to conferences hosted by the customer, or it could be allocated only temporarily to the customer for a limited time.
[0024] Another communication service that is suitable for promotion through this invention is oral recitation of textual data. Many consumers receive information in electronic form, through electronic mail or other channels. However, when a customer lacks the necessary equipment to retrieve and/or review the information, a proxy service that can access the information and communicate it to the customer may be useful. This service comprises receiving a voice telephone call from the customer, identifying textual data that the customer wishes to review, locating the data and reading it to the customer over the voice telephone connection. The identification, location, and reading can all be performed by an automated attendant system.
[0025] Another communication service that is suitable for promotion through this invention is “find-me/follow-me.” In this service, a customer can obtain a special telephone number that is connected to a find-me/follow-me server, which is capable of locating the customer and connecting calls to him based on a set of rules and other information. Thus, calls from certain originating phone numbers might be forwarded to the customer's home phone, cell phone, or a phone near the customer's present physical location (if that location was known). Alternatively, unwanted calls might be directed to voicemail or simply dropped after a notification that the customer was “presently unavailable.”
[0026] A sample interaction with such an automated attendant is depicted in FIG. 3 . The customer 301 places a voice call to the automated attendant 302 , and issues a request to “read e-mail,” 303 . The attendant responds with the number of messages found 304 . The customer instructs the attendant to find a particular message 305 , and the attendant responds with information 306 about any messages located. Finally, the customer can instruct the attendant to read the message 307 , and the attendant complies 308 .
[0027] It will be apparent to one of ordinary skill in the art that other communication services, beyond those discussed previously, can also be promoted by means of the invention.
[0028] Possible promotion patterns include offering to transmit X facsimile pages for free for each Y voice mail messages or facsimile pages received, up to a selectable maximum of number of pages or messages in either direction, or up to a maximum number of pages or messages per unit of time such as a day, week, or month. Pages transmitted in excess of the free pages earned might be billed at an appropriate rate determined by the merchant, which may incorporate such considerations as reduced rates for certain destinations or for volume exceeding a certain number of pages. Alternate promotion patterns include offering a selectable number of minutes of conference call activity or interaction with an automated attendant to review electronic information in exchange for receiving or transmitting a number of facsimile pages.
[0029] An embodiment of the invention may be a machine-readable medium having stored thereon instructions which cause a processor to perform a process according to an embodiment of the invention. In other embodiments, operations might be performed by specific hardware components that contain hardwired logic. Those operations might alternatively be performed by any combination of programmed computer components and custom hardware components.
[0030] A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer), not limited to Compact Disc Read-Only Memory (CD-ROMs), Read-Only Memory (ROMs), Random Access Memory (RAM), Erasable Programmable Read-Only Memory (EPROM), and a transmission over a data network such as the Internet.
[0031] The applications of the present invention have been described largely by reference to specific examples and in terms of particular allocations of functionality to certain hardware components. However, those of skill in the art will recognize that alternate communication services may also be promoted in the manner disclosed, and that hardware and software functionality may be distributed among a large number of cooperating machines or may be performed by a single device. Such variations and implementations are understood to be apprehended according to the following claims. | A method to promote use of one communication service by associating it with another service and offering incentives to use the first service in return for use of the second service. Other embodiments are also described and claimed. | Summarize the information, clearly outlining the challenges and proposed solutions. | [
"BACKGROUND [0001] The growth and adoption of wide-area data networks such as the Internet have enabled merchants to offer a number of new services to consumers.",
"These services often center around data manipulation and storage, and can be provided to a large number of consumers without significant setup or operational expense.",
"As a result, merchants often provide these services to consumers gratis, and look to alternate revenue sources such as advertising and data aggregation (that is, collection and sale of data about consumers'",
"preferences and habits) in hopes of creating a viable business.",
"Unfortunately, operating a service business in this manner engenders a feeling of entitlement to future free service among consumers.",
"Consequently, merchants find it difficult to provide new services which do require significant investment or operating capital, because consumers are reluctant to try a new service that is not free, yet many services cannot economically be provided for the amount of money that can be earned by advertising or data aggregation.",
"[0002] Merchants have commonly addressed this problem by simply offering the new, expensive-to-provide service gratis (and at a financial loss) during an introductory period, in the hope that consumers will find the service valuable or indispensable and continue to use it when the introductory period terminates and the service must be paid for.",
"However, this all-or-nothing approach does not work well given consumers'",
"feelings of entitlement to free services;",
"even if the new service is convenient or useful, a consumer faced with the choice to “pay up”",
"or get out will often grumble and stop using the service, and may become annoyed enough to abandon the merchant's other services as well.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0003] Embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements.",
"It should be noted that references to “an”",
"or “one”",
"embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.”",
"[0004] FIG. 1 depicts an overview of the components that may be involved in one or more embodiments of the invention.",
"[0005] FIG. 2 depicts an embodiment of the invention wherein a customer who uses the merchant's system to receive Y facsimile pages earns credit to use the merchant's system to transmit X facsimile pages.",
"[0006] FIG. 3 depicts a possible interaction between a customer and an automated server, in a service provided through another embodiment of the invention.",
"DETAILED DESCRIPTION [0007] In the information-services realm, and particularly in the realm of communication services, a single performance of a service is often of very small value, yet the ability to obtain that service at any time is important and valuable.",
"This disparity is reflected in the pricing structure for Internet services, for example.",
"Currently, most businesses charge a fee for generalized Internet access (hourly, or more commonly, monthly) but do not impose any extra charge for amount of data transferred, number of websites visited, or number of electronic mail messages sent or received, although it would be technologically feasible to do so.",
"[0008] A further economic pressure that favors pay-for-availability over pay-per-use pricing is the high (relative) transaction cost associated with small monetary value transactions.",
"As previously noted, the value of receiving a single performance of a service is often very small.",
"However, there are no viable, widely-accepted micropayment systems that would support a pay-per-use pricing scheme for very small transaction amounts.",
"There is simply no efficient way to sell a service for a fraction of a cent, or even for a few cents—all commonly-used payment methods have a transaction cost in excess of that amount.",
"[0009] In one embodiment of the invention, the merchant offers a customer credit toward one service when the customer uses another service.",
"(Note that the term “customer”",
"as used herein includes persons or entities with which the merchant has an existing commercial relationship, as well as persons or entities with which the merchant is attempting to establish a new relationship.) The merchant can maintain an account of these credits, which obviates the problem of dealing in small monetary amounts (in current-dollar terms, the range between zero and a few tens of cents, for example).",
"Furthermore, by maintaining such an account, the merchant can fine-tune the credit offered much more precisely than can a typical merchant of physical goods who operates a typical customer loyalty program.",
"Different credit amounts, including fractional credits, can be given based on the behaviors the merchant wants to encourage or discourage.",
"For example, if the merchant offered services A (which was inexpensive or free, and widely used) and B (which was relatively expensive to provide and not widely used), it could encourage users to try B by offering a credit toward B each time a customer used A. However, once a particular customer had begun to use B regularly, the merchant could reduce the credit earned by using A, or transition to a B-only credit plan, where a customer would earn credit for future performances of B by using B. [0010] Embodiments of the invention are well-suited to providing a variety of somewhat specialized communication services.",
"For general communication services such as telephone, pager or electronic mail service, the mere availability of the service may be so valuable that consumers are willing to enter into long- or indefinite-term, monthly service contracts even if they do not always use the full amount of service to which they are entitled.",
"However, for more specialized services such as facsimile transmission and reception, voicemail, conference call management, or oral recitation of textual data by a machine, a customer might be unwilling to enter a monthly contract when it is uncertain whether he will use the service at all in a particular month.",
"Such services could be excellent candidates for pay-per-use sales strategies, but for reasons already discussed, it may not be possible to sell them in that manner.",
"However, by applying the fractional credit accounting and incentive system disclosed, it becomes feasible to offer these services on a pay-per-use basis.",
"[0011] In an embodiment of the invention, a merchant such as j2 Global Communications of Hollywood, California, could offer facsimile reception and transmission services to its customers.",
"Both services may require equipment and telephone lines to communicate with traditional facsimile equipment, so some capital expenditure may be necessary to provide those services.",
"However, for sending facsimiles, outbound calling charges are also incurred, and so that service may be more expensive to provide.",
"Thus, while it might be possible to provide facsimile reception services for free, the merchant could not provide transmission services without charging the customer.",
"By applying an embodiment of the invention, the merchant could introduce a customer to the transmission service on a basis that is equivalent to a free introductory period (by giving a certain number of free transmission credits), and transition smoothly over time to a pay-per-use model by adjusting the credits given for the customer's use of sending and receiving services, ultimately arriving at the point where the customer would have confidence in the commercial relationship and would be willing to leave funds on account with the merchant to pay for future facsimile transmissions.",
"In one specific application of an embodiment of the invention, a customer could earn credits to send a first number of outbound facsimile pages each time he receives a second number of inbound pages (both the first number and the second number being selectable by the merchant).",
"[0012] FIG. 1 depicts a number of elements that may be involved in one or more embodiments of the invention that involve providing fax and voicemail services.",
"A merchant such as j2 Global Communications of Hollywood, Calif.",
", may maintain one or more co-located data centers 120 a , 120 b , which may be located in diverse physical locations.",
"Such diverse locations may be chosen to facilitate connections 111 a , 111 b to local telephone switching stations (not shown) that are part of a public switched telephone network (PSTN) 110 .",
"Connections to local telephone switching stations may be desired because they allow the connected machines to be accessed through the PSTN by a local phone number (as opposed to a long-distance phone number).",
"For example, if a co-located data center was placed in Tokyo, Japan, then the connected machines could place and receive inexpensive local phone calls to other phones in Tokyo, and less-expensive calls to and from other locations in Japan, as compared to such calls placed to or from a machine located in Geneva, Switzerland.",
"[0013] The co-located data centers may contain a number of server functions such as web server 121 , electronic mail (e-mail) server 122 , database server 123 , voice mail server 124 , and fax server 125 .",
"Each function may be distributed among a number of physical machines, or a number of functions may be consolidated in one machine.",
"The machines may be connected to a data communication network 126 , which allows them to communicate with each other and with a network routing and/or security device such as firewall 127 .",
"[0014] Each co-located data center may be able to communicate with other centers and/or with a central data center 150 through a variety of data networks, such as private data network 130 , virtual private network (VPN) 135 , and/or public data network 140 .",
"The Internet is a well-known example of a public data network.",
"Data transmitted over a private network are relatively secure against eavesdropping, but data transmitted over a public network such as the Internet may be exposed to third parties at many points.",
"A VPN uses encryption to transmit data securely between two locations over either public or private data networks.",
"Data are much less vulnerable to eavesdropping and modification while in transit across a VPN, so the computers using the VPN to communicate may not need to encrypt their data separately to protect it, although such encryption may provide additional security.",
"[0015] The merchant may operate a central data center 150 , containing server functions such as file server 151 , database server 152 , web server 153 , and email server 154 .",
"Each server function may be distributed across a number of physical machines, or several server functions may be consolidated on a single physical machine.",
"Each machine may be connected to a network 155 , which may provide access to private data networks 130 , VPNs 135 , and/or public data networks 140 through a network routing and/or security device such as firewall 156 .",
"[0016] The merchant's customers and other participants in an embodiment of the invention include fax machines 100 and customers who connect to the PSTN by means of a land line 101 or a cell phone 102 .",
"Customers may interact with services provided by the merchant over a data network by means of computers 165 and 170 , which may be connected directly to a public data network 140 or to the network through an ISP 160 .",
"[0017] A specific example of the way in which facsimile reception could be provided may be explained with reference to FIG. 1 .",
"A person who wished to transmit a facsimile to a customer could send it through PSTN 110 from his fax machine 100 to a fax server 125 located in one of the merchant's co-located data centers 120 a , 120 b .",
"The fax server could convert the facsimile signal into one or more tag image file format (TIFF) files.",
"These files could be assembled into an e-mail message and sent directly to an e-mail address of the customer by e-mail server 122 , where the customer's e-mail address could be obtained from database server 123 .",
"For added security, the message could be encrypted prior to transmission by formatting the message as an S/MIME message.",
"The customer could view the facsimile by retrieving the e-mail message, decrypting it if necessary, and displaying the TIFF file attachments.",
"[0018] Alternatively, to provide increased security without the difficulty of maintaining encryption key information for each customer, the merchant could arrange a VPN connection from a co-located data center to a data center serving a number of customers (not shown).",
"The e-mail containing the TIFF attachments could be transmitted to the data center serving a number of customers securely over the VPN, and could later be retrieved from the second data center by the customer.",
"[0019] In yet another alternative, the merchant could transmit the e-mail message from its co-located data center 120 a securely by means of a VPN connection 135 to its own central data center 150 .",
"Once received in the central data center, the TIFF attachments could be removed from the e-mail message, encrypted, and stored on database server 152 .",
"Then, a notification e-mail message could be sent from the e-mail server 154 to the customer's computer 165 or 170 , informing the customer that a facsimile was available for viewing.",
"The customer could connect to the merchant's web server 153 through public data network 140 , using a secure protocol such as HTTPS, authenticate himself to the web server through an appropriate challenge-and-response sequence, and download or display the facsimile from the database server 152 .",
"This alternative may provide favorable security characteristics because the facsimile data are always protected by encryption while being transmitted from one place to another.",
"[0020] To provide facsimile transmission services, the merchant could accept electronic mail sent from a customer's computer ( 165 or 170 ) to the merchant's mail server 154 .",
"This mail could contain a destination facsimile number and an attached document or image file to be transmitted.",
"A server in the central data center could determine which co-located data center would provide the best connection to the destination facsimile machine, where the best connection may be selected on the basis of geographical proximity, low outbound calling cost, quality of connection, or other criteria.",
"Once a “best”",
"data center was selected, the email could be forwarded to the email server there, and then to a facsimile server.",
"The facsimile server could convert the document or image file into a format suitable for transmission via facsimile, and then connect to the destination facsimile machine and send the converted document or image.",
"After transmitting the document (or after attempting but failing to transmit the document), the facsimile server could transmit an email message notifying the customer of the result of the transmission.",
"[0021] In another embodiment of the invention, voice message communication services may be promoted.",
"A customer could be provided with a telephone number that is connected to inbound call processing equipment.",
"When a calling party dials the number, he would be asked to leave a voice message for the customer.",
"When a message has been recorded, the customer could be notified through electronic mail or other means, and can retrieve the message at his leisure.",
"Alternatively, the message could be converted into an electronic format and transmitted directly to a network address of the customer, without the need to store it on any of the merchant's systems.",
"[0022] In the context of facsimile and/or voice mail reception and facsimile transmission services, the embodiment of the invention depicted graphically in FIG. 2 would permit the merchant to offer to transmit X facsimile pages for a customer each time the customer receives Y voice mail messages or facsimile pages, where “X”",
"and “Y”",
"are non-negative numbers, and “X”",
"need not be an integer.",
"The merchant 201 would provide a telephone number 202 to the customer 203 , where the telephone number was connected to a device 206 maintained by the merchant that can record voice mail messages and/or receive facsimiles.",
"The customer could give the telephone number to third parties 204 as the customer's own voice mail or facsimile number.",
"When a voice mail message or facsimile is sent to that telephone number 205 , the merchant's device 206 receives it and may retransmit it to the customer, store it locally, or forward it to a central repository for later retrieval by the customer.",
"In addition, the device 206 may notify the customer that the message or facsimile has been received.",
"When Y messages and/or pages have been received, the customer's account 207 is credited so that the customer can send X facsimile pages by using the merchant's equipment, according to the method described above.",
"After transmission, the merchant could deduct the number of pages sent from the customer's credit balance.",
"[0023] Another communication service that is suitable for promotion though this invention is conference call management.",
"A merchant could provide a telephone number to a customer, where the telephone number is connected to equipment that can receive multiple callers and connect them in a conference-call fashion.",
"The telephone number could be dedicated to conferences hosted by the customer, or it could be allocated only temporarily to the customer for a limited time.",
"[0024] Another communication service that is suitable for promotion through this invention is oral recitation of textual data.",
"Many consumers receive information in electronic form, through electronic mail or other channels.",
"However, when a customer lacks the necessary equipment to retrieve and/or review the information, a proxy service that can access the information and communicate it to the customer may be useful.",
"This service comprises receiving a voice telephone call from the customer, identifying textual data that the customer wishes to review, locating the data and reading it to the customer over the voice telephone connection.",
"The identification, location, and reading can all be performed by an automated attendant system.",
"[0025] Another communication service that is suitable for promotion through this invention is “find-me/follow-me.”",
"In this service, a customer can obtain a special telephone number that is connected to a find-me/follow-me server, which is capable of locating the customer and connecting calls to him based on a set of rules and other information.",
"Thus, calls from certain originating phone numbers might be forwarded to the customer's home phone, cell phone, or a phone near the customer's present physical location (if that location was known).",
"Alternatively, unwanted calls might be directed to voicemail or simply dropped after a notification that the customer was “presently unavailable.”",
"[0026] A sample interaction with such an automated attendant is depicted in FIG. 3 .",
"The customer 301 places a voice call to the automated attendant 302 , and issues a request to “read e-mail,” 303 .",
"The attendant responds with the number of messages found 304 .",
"The customer instructs the attendant to find a particular message 305 , and the attendant responds with information 306 about any messages located.",
"Finally, the customer can instruct the attendant to read the message 307 , and the attendant complies 308 .",
"[0027] It will be apparent to one of ordinary skill in the art that other communication services, beyond those discussed previously, can also be promoted by means of the invention.",
"[0028] Possible promotion patterns include offering to transmit X facsimile pages for free for each Y voice mail messages or facsimile pages received, up to a selectable maximum of number of pages or messages in either direction, or up to a maximum number of pages or messages per unit of time such as a day, week, or month.",
"Pages transmitted in excess of the free pages earned might be billed at an appropriate rate determined by the merchant, which may incorporate such considerations as reduced rates for certain destinations or for volume exceeding a certain number of pages.",
"Alternate promotion patterns include offering a selectable number of minutes of conference call activity or interaction with an automated attendant to review electronic information in exchange for receiving or transmitting a number of facsimile pages.",
"[0029] An embodiment of the invention may be a machine-readable medium having stored thereon instructions which cause a processor to perform a process according to an embodiment of the invention.",
"In other embodiments, operations might be performed by specific hardware components that contain hardwired logic.",
"Those operations might alternatively be performed by any combination of programmed computer components and custom hardware components.",
"[0030] A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer), not limited to Compact Disc Read-Only Memory (CD-ROMs), Read-Only Memory (ROMs), Random Access Memory (RAM), Erasable Programmable Read-Only Memory (EPROM), and a transmission over a data network such as the Internet.",
"[0031] The applications of the present invention have been described largely by reference to specific examples and in terms of particular allocations of functionality to certain hardware components.",
"However, those of skill in the art will recognize that alternate communication services may also be promoted in the manner disclosed, and that hardware and software functionality may be distributed among a large number of cooperating machines or may be performed by a single device.",
"Such variations and implementations are understood to be apprehended according to the following claims."
] |
RELATED APPLICATION DATA
This application is a continuation of U.S. application Ser. No. 10/869,178, filed Jun. 15, 2004 (now U.S. Pat. No. 7,454,034), which is a continuation of U.S. application Ser. No. 10/229,382, filed Aug. 26, 2002 (now U.S. Pat. No. 6,751,337), which is a continuation of U.S. application Ser. No. 09/228,224, filed Jan. 11, 1999 (now U.S. Pat. No. 6,442,283). These patents are incorporated herein by reference.
FIELD OF THE INVENTION
This invention relates generally to multimedia data, and more particularly to multimedia data embedding.
BACKGROUND OF THE INVENTION
With the increasingly popularity of multimedia-capable computers, and the digitalization of multimedia in general, the importance of multimedia data embedding has become more important. In one type of multimedia data embedding, a key, also know as a watermark, is embedded into multimedia data, a process which is known as watermarking. This allows questions of ownership of a given piece of multimedia data—which may be widely distributed by virtue of the Internet, for example—to be resolved, by attempting to decode the key from the multimedia data. That is, by watermarking multimedia data, the data owner can determine whether a suspect piece of multimedia data is his or hers by determining whether the watermark is present in the suspect data.
For example, a record company, prior to making its music selections available on the Internet for widespread purchase and use, can first watermark the data representing a music selection. If a site on the Internet is providing bootleg copies of the music selections, but claims that the copies are not in fact owned by the record company, the company can prove that they are indeed owned by it by showing that the watermark is present in the bootleg copies. Therefore, watermarking has applicability to audio multimedia, as well as other types of multimedia, such as image and video multimedia.
SUMMARY
The invention provides methods for embedding and decoding data embedded in media signals and related software implementations.
One aspect of the invention is a method for embedding data into a media signal. The method receives a media signal, divides the media signal into blocks of samples, and calculates a function of the samples in the blocks, including transformations of samples in the blocks to corresponding block values. A processor uses the block value to determine a factor for samples in the blocks to be multiplied by the samples so that when a data embedding function is evaluated for the block, an output of the data embedding function corresponds to a data value representing desired digital data embedded in the block.
Another aspect of the invention is a method of decoding data embedded in a media signal. Like the embedder, the decoder divides the media signal into blocks of samples and calculates a function of the samples in the blocks, including transformations of samples in the blocks to corresponding block values. A processor processes the block value to evaluate a data embedding function to determine digital data embedded in the block.
In one digital watermark embodiment, a decoder projects a digitally watermarked signal into a direction according to a key. It applies a weighting function to the projected signal to compute a projected signal in which parts of the digitally watermarked signal that are more robust to distortion are weighted more than parts that are less robust to the distortion. The method recovers embedded auxiliary data symbols from the projected signal by quantizing the projected signal to determine a binary symbol associated with a quantization of the projected signal.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a flowchart of a computer-implemented embedding method according to an embodiment of the invention;
FIG. 2 shows a flowchart of a computer-implemented decoding method according to an embodiment of the invention;
FIG. 3 shows a diagram of a system according to an embodiment of the invention; and,
FIG. 4 shows a diagram of a computer in conjunction with which embodiments of the invention may be practiced.
DETAILED DESCRIPTION OF THE INVENTION
In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the spirit or scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.
Some portions of the detailed descriptions which follow are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the present invention, discussions utilizing terms such as “processing” or “computing” or “calculating” or “determining” or “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.
Methods
Referring first to FIG. 1 , a computer-implemented embedding method according to an embodiment of the invention is shown. That is, the method of FIG. 1 embeds a key p into multimedia data x, to generate watermarked data x′. The computer-implemented method is desirably realized at least in part as one or more programs running on a computer—that is, as a program executed from a machine-readable medium such as a memory by a processor of a computer. The programs are desirably storable on a machine-readable medium such as a floppy disk or a CD-ROM, for distribution and installation and execution on another computer, for example, over the Internet.
In block 100 , a vector x is received that represents multimedia data, such as audio, image, or video data; the invention is not so limited. In block 100 ,
x=[x (0) x (1) . . . x ( N− 1)]
and denotes a vector of N data samples.
In block 102 , a vector p is received that represents a pseudo-random sequence. The vector p is the key or watermark that is to be embedded in the vector x. More specifically,
p=[p (0) p (1) . . . p ( N− 1)]
and represents a cryptographically secure pseudo-random sequence generated from a one-way function and a key, as known within the art.
In block 104 , a vector x′ is generated, in which the vector p is embedded into the vector x. The vector x′ is the watermarked data, or the data into which the key has been embedded. More specifically, the new data vector
x′=[x ′(0) x ′(1) . . . x ′( N− 1)]
is generated by adding a second vector to the data vector x producing the new data vector
x′=x+aq (1)
where a is a perception-based scaling factor and vector q is a perceptually weighted pseudo-random sequence. Both components a and q are perception-based to insure that x and x′ are indistinguishable to the human audio or visual systems for audio and image/video data, respectively. The computation of q and a depend on the pseudo-random sequence p and a weighting mechanism as described below. Note that the new data vector in (1) may be represented by
x ′ = x + ∑ n = 0 N - 1 a n q n
where N orthogonal pseudo-random sequences q n are employed. Each term a n q n is used to carry one bit of information.
Referring next to FIG. 2 , a flowchart of a computer-implemented decoding method is shown. That is, the method of FIG. 2 generates a key vector p as embedded from a multimedia vector x′, as such a multimedia vector x′ has been generated in accordance with the method of FIG. 1 . Like the method of FIG. 1 , the computer-implemented method of FIG. 2 is desirably realized at least in part as one or more programs running on a computer—that is, as a program executed from a machine-readable medium such as a memory by a processor of a computer. The programs are desirably storable on a machine-readable medium such as a floppy disk or a CD-ROM, for distribution and installation and execution on another computer, for example, over the Internet.
In block 200 , a multimedia vector x′ is first received, from in which a key p has been embedded into a multimedia vector x. In block 202 , the key p is decoded from the vector x′. To decode the embedded data, a scaled inner product between the new data vector x′ and the pseudo-random sequence p is computed
1 T ∑ i = 0 N - 1 p ( i ) x ′ ( i ) w ( i ) = 1 T ∑ i = 0 N - 1 p ( i ) x ( i ) + aq ( i ) w ( i ) = 1 T ∑ i = 0 N - 1 p ( i ) x ( i ) w ( i ) + a T ∑ i = 0 N - 1 p ( i ) q ( i ) w ( i ) ( 2 )
where w is a vector of weights as described below. The value of T dictates the quantization step of the algorithm and is dependent on the weighting-mechanism employed. The first term on the right hand side of (2) is referred to as the residual. It represents the projection of the original data sequence x onto the pseudo-random direction p weighted by w. The second term on the right hand side of (2) is the projection of the shaped pseudo-random sequence q with the pseudo-random direction p weighted by w.
As described in (1), the second term carries the embedded information. The residual R
R = 1 T ∑ i = 0 N - 1 p ( i ) x ( i ) w ( i ) ( 3 )
is known. Using this knowledge, a variable d is defined where
d=B−R
and
B = { 0 if b = 1 1 / 2 if b = 0 and R > 0 - 1 / 2 if b = 0 and R < 0
where b is the data bit to embed. The variable a in (1) is computed as
a
=
dT
∑
i
=
0
N
-
1
p
(
i
)
q
(
i
)
w
(
i
)
(
4
)
Substituting (3) and (4) into (2), the embedded data can be recovered without error in an environment without distortion.
In at least some embodiments of the invention, factors to consider when embedding data in audio, the weighting function w, and the shaped pseudo-random sequence q are described below.
Audio Data Hiding Considerations
The audio data hiding algorithm works by making perceptually insignificant modifications to the audio samples. The audio signal is modified in blocks of size Nb, i.e., Nb consecutive samples of the audio are processed at the same time. In one implementation, the blocks are non-overlapping. However, overlapping blocks may be used.
The data embedding algorithm described above is computed in the discrete cosine transform (DCT) domain for audio signals. Due to the presence of efficient Fast Fourier Transform methodologies known in the art, Nb is typically selected as a power of 2, e.g., Nb=1024. The size of the block is controlled by several factors. Since audio characteristics may change rapidly, the block size should be small to keep modifications localized in time. Smaller block sizes are also preferred during the decoding process during synchronization. However, the block size should be large enough to provide a high frequency resolution. The DCT frequency resolution is computed as
fd = fs 2 Nb
where fs is the sampling frequency of the audio signal. For Nb=1024 and fs=44100 Hz, the frequency resolution is fd=21.53 Hz.
A length Nb block of audio samples produces Nb DCT coefficients. In the standard implementation, the DCT spectrum is generally segmented into smaller subbands. In particular, a subset of length N<Nb of the DCT coefficients is used to embed each data bit as described in (1). Each subband may consist of a different number of DCT coefficients. For example, the spectrum may be segmented into three bands in the frequency ranges of 1000-4000 Hz, 4000-8000 Hz, and 8000-15000 Hz.
The audio data embedding procedure also includes the MPEG psychoacoustic masking model 1 or 2 , as known in the art, for checking tolerable error levels. The MPEG masking model is used to verify the perceptual quality of (1). Components of the embedded data signal may be scaled or clipped to meet the requirements of the masking model.
The Pseudo-Random Sequence
In one embodiment, one or two random keys x 1 and x 2 (i.e., seeds) are used from which a pseudo-random sequence p can be generated, by using a suitable pseudo-random sequence generator, such as described in R. Rivest, “Cryptography,” pp. 717-755, in J. van Leeuwen (ed.), Handbook of Theoretical Computer Science, Vol. 1, Ch. 13, MIT Press, Cambridge, Mass., 1990, which is hereby incorporated by reference. Only the first key, x 1 , is used for most data embedding applications. The second key, x 2 , is required for watermarking audio. It is used to make counterfeiting very difficult. Popular generators include RSA, Rabin, Blum/Micali, and Blum/Blum/Shub, as known in the art, and as described in S. Goldwasser, M. Bellare, “Lecture notes on cryptography”, preprint, July 1996: http://www-cse.ucsd.edu/users/mihir/papers/crypto-papers.html. With the proper keys, the embedded data may be extracted. Without the key(s), the data hidden in the signal is statistically undetectable and impossible to recover. Note that classical maximal length pseudo noise sequence (i.e., m-sequence) generated by linear feedback shift registers are not used to generate a pseudo-random sequence. Sequences generated by shift registers are cryptographically insecure: one can solve for the feedback pattern (i.e., the keys) given a small number of output bits p.
The noise-like sequence p can be used to derive the actual watermark hidden into the audio signal or control the operation of the watermarking algorithm, e.g., determine the location of samples that may be modified. The key x 1 is author dependent. A second key, x 2 , is signal dependent. The key x 1 is the key assigned to (or chosen by) the author. Key x 2 is computed from the audio signal when the author wishes to watermark the audio signal. It is computed from the signal using a one-way hash function. For example, the tolerable error levels supplied by masking models are hashed to a key x 2 . Any one of a number of well-known secure one way hash functions may be used to compute x 2 , including RSA, MD4, and SHA, as known in the art. MD4 is specifically described in R. Rivest, “The MD4 message digest algorithm”, pp. 303-311 in Advances in Cryptology, CRYPTO 92, Springer, Tokyo, 1991, which is hereby incorporated by reference; SHA is specifically described in National Institute of Standards and Technology (NIST), Secure Hash Standard, NIST FIPS Pub. 180-1, April 1995, which is also hereby incorporated by reference. For example, the Blum/Blum/Shub pseudo-random generator uses the one way function y=g_n(x)=x^2 mod n where n=pq for primes p and q so that p=q=3 mod 4. In at least some embodiments, generating x or y from partial knowledge of y is computationally infeasible for the Blum/Blum/Shub generator.
A QR orthogonal-triangular decomposition operation is performed on the pseudo-random sequences before they are employed by the data embedding algorithm. A typical pseudo-random sequence generator creates a sequence of samples with values ranging from −1 to +1. The relative magnitudes of samples in the sequence may be on the order of 10^6, leading to spiking and poor weighting characteristics. A QR decomposition is employed to maintain a relative magnitude in the samples on the order of 0.9 to 1.1.
The Weighting Function
A number of functions to weight the pseudo-random sequence p for robustness and perceptual quality can be been employed in accordance with different embodiments of the invention. The weighting coefficients w are generally computed as a function of the data coefficients x.
One method to generate the weighting values includes computing the average of the absolute value of the data coefficients about a length Nf interval
w
(
i
)
=
1
Nf
∑
k
=
-
*
Nf
-
1
)
/
2
(
Nf
-
1
)
/
2
x
(
i
-
k
)
The value of Nf is kept small to keep the averaging localized, e.g., Nf=13. Out-of-band DCT coefficients were used at the boundaries of the averaging interval.
In other embodiments of the invention, the DCT subband is segmented into critical bands as described by the MPEG psychoacoustic model 1 , known within the art. Each subband consists of Nc critical bands. The varying length critical bands increase in size with frequency. Several techniques to compute the weight wi for each critical band were employed. Note that each wi is a vector of the same length as each critical band.
In some embodiments, the weighting function is computed independently for each critical band. These include the one-norm,
w ( i ) = w 1 ( i ) = ∑ k ∈ CB x ( k )
two-norm,
w ( i ) = w 2 ( i ) = ( ∑ k ∈ CB x ( k ) 2 ) 1 / 2
and infinity-norm
w ( i )= w∞ ( i )=max| x ( k )|
Each of the weights is constant over its corresponding critical band.
The purpose of the weighting function is to approximate the relative tolerable error level for each DCT component and the corresponding accuracy at the receiver. For example, a weight for a tonal critical band may be large. However, the weight relative to the tonal is small. This is designed to emulate coding algorithms which generally introduce a smaller relative error in tonal components than in non-tonal components.
As the weight estimate is required at the receiver, the weighting function is required to be robust to many distortions. The aforementioned weighting functions are designed to perform well in terms of relative error before and after distortions to the host audio signal. In most cases the value of the weighting function wi depends on several data samples.
The Shaped Pseudo-Random Sequence
The second term in the data embedding methodology (1) includes two components: a and q. The a term was defined in (4). The shaped pseudo-random sequence, q, may be computed in a variety of manners from the secure pseudo-random sequence p.
In one embodiment, the shaped pseudo-random sequence is defined as
q=p*w
where w consists of a weighting function defined in the previous section and * represents a component-by-component multiplication. As a result, the modification to the original data sequence is a scaled version of the pseudo-random sequence shaped by the weights.
A second approach employs a finer resolution in the modification by defining the shaped pseudo-random sequence as
q=p*|x| (5)
In this case, the pseudo-random sequence is shaped by the absolute value of the data it is modifying. The finer resolution in this case is due to the fact that the weights wi in the previous section are constant over multiple samples, i.e., the critical band. The modification in is performed at an individual sample level.
The previously described shaping techniques for the pseudo-random sequence only take into account frequency shaping, in at least some embodiments of the invention. To insure that the data embedding algorithm avoids pre- and post-echo distortions, a temporal shaping component is introduced. Recall that the embedding methodology is computed in the frequency domain. Let xt denote the data block in the time domain. Note that the length of the time data vector is Nb, i.e., the same length as the DCT block. To account for temporal shaping, the envelope of the data signal in the time domain is generated. First the DCT of the absolute value of the data in the time domain is computed
X=dct (| xt |)
A second DCT signal X′ is generated by retaining only the first K low frequency coefficients of X
X ′ = { X ( i ) if 0 ≤ i ≤ K 0 otherwise
Typically, 6<K<10 depending on the desired amount of smoothing of the envelope. An inverse DCT computation is performed on X′ generating a smoothed envelope m of the data signal.
To generate q, an intermediate signal q′ is computed as described in (5)
q′=p*|x|
The time-domain representation, qt′, of the pseudo-random sequence q′ is computed by
qt′=idct ( q ′)
and multiplied by the envelope m, generating a temporally-shaped pseudo-random sequence
qt″=m*qt′ (6)
The DCT of the temporally-shaped pseudo-random sequence is computed, resulting in the final shaped pseudo-random sequence
q=dct ( qt ″)
The value of a is then computed as described by (4). Note that the pseudo-random sequence p is shaped in both the frequency and time domains to increase the perceptual quality of the embedded data.
In one particular embodiment, a window h is introduced in (6). In particular, the window is introduced to generate a temporally-shaped and windowed pseudo-random sequence
qt″=h*m*qt′
The other calculations are not affected. A rectangular window introduces an audible blocking effect in some audio signals. A shaped window h that tapers off near the beginning and ending of the block prevents the blocking noise. Gaussian and trapeziodal windows, as known in the art, are employed by the data embedding methodology.
A different approach to compute q based on coding error is now described. In this embodiment, the coded audio signal xc at the target bit rate and coding algorithm is generated and used to obtain the coding error
e=x−xc
The shaped pseudo-random sequence q is computed as
q=p*e
The approach exploits perceptual characteristics of most current audio coding algorithms. In particular, the coding error e generated by popular algorithms, e.g., Dolby's AC-3 and MPEC, as known in the art, is typically perceptually shaped.
In a related embodiment, the value of a described in (4) is modified to take into account coding error. Several different values of a are computed according to
a = b dT ∑ i = 0 N - 1 p ( i ) q ( i ) w ( i )
where 0<<b<1 is employed to tweak to the value of a to the best value for the target bit rate. Each is tested by coding the embedded audio algorithm and recovering the embedded data bit. The best a is selected.
Tonal Detection
Tonal (harmonic) and non-tonal (residue) components in an audio signal have different perceptual characteristics based on the masking properties of the human auditory system. For example, the amplitude of non-tonal and low level noise components in an audio signal may be modified in the range of 50-100% without a perceptually significant change to the audio. Perceptual changes in tonal components, however, may sometimes be detected after only a 10\% change in amplitude. The strength of embedded data may be limited by maximum allowable changes to the tonal components. To enhance the audio data hiding algorithm, a tool to detect the tonal components in audio signals was developed. By separating tonal and non-tonal components, the data embedding algorithm is able to maximize the strength of each component independently.
The tonal components in an audio signal are identified using a harmonic analysis technique as described in D. J. Thomson, “Spectrum estimation and harmonic analysis,” Proceedings of the IEEE, vol. 70, no. 9, pp. 1055-1096, September, 1982, which is hereby incorporated by reference. The analysis provides an accurate estimate of the location (frequency), amplitude, and phase of harmonic components in the audio. As described in the following section, this information may be used to change the weighting function. It may also used in an alternative data hiding.
The technique described in Thomson analyzes harmonic components in an audio signal by expanding the audio signal in terms of a set of orthogonal windows called prolate sequences. The expansion is followed by a statistical F-test to determine whether a tonal component exists at a particular frequency.
The harmonic analysis is performed on segments of Nb audio samples as described in the previous section. The audio segment is multiplied (windowed) by a set of K prolate sequences. A zero-padded discrete Fourier transform of each windowed data sequence is then computed. The windowing provides K different estimates of the spectrum based on the K different prolate windows. Zero-padding is used to prevent circular wrapping and provide a high level of frequency resolution. Typically the sequence is zero-padded to 2 Nb or 4 Nb The harmonic mean at each frequency is then computed followed by an F-test statistic is then computed. The F-value at each frequency is a measure of the ratio of the estimate of the magnitude of the harmonic at that frequency to that of the non-tonal part of the spectrum. If a tonal exists at a particular frequency, the F-value will be large. A small F-value indicates that the component is non-tonal. The frequencies corresponding to tonals in the audio are obtained by finding peaks in the F-statistics. The frequency, amplitude, and phase of each tonal component are then provided to the audio data embedding algorithm. The process is repeated on each length Nb segment of the audio.
Tonal Weighting
The tonal detection methodology provides the position (frequency) of each tonal component in a length Nb block of audio. With the tonal detection and audio data embedding algorithms synchronized in time and employing the same number of audio samples Nb, the data embedding algorithm uses the detected tonals occurring in each frequency band to modify the weighting function. Weights corresponding to tonal components (and frequency components near the tonal) are scaled differently than non-tonal components, let z denote the set of tonal indexes returned by the tonal detection algorithm. A modified version x′ of the data x is generated such that
x ′ ( k ) = { Bx ( k ) if k ∈ z x ( k ) otherwise
where 0<B<1 is a scaling value for tonal components. Parameter q is computed as described earlier using x′ in place of x, i.e.,
q′=p*|x′|
As a result, the tonal and non-tonal components of the data have a different effect on the computation of q through the use of the parameter B. This allows the algorithm to modify the amplitude of tonal components, e.g., by +/−10%, differently than non-tonal components, e.g, by +/−50%. The same tonal detection algorithm is employed by the receiver to generate the appropriate weights and recover the embedded information.
Tonal Shifting
An alternative embedding scheme employing tonal detection is now described. The embedding methodology first separates the original audio signal into a tonal component and a residual (non-tonal) component
x=x r +x t
This embodiment uses the frequency, amplitude, and phase information provided by the tonal detection procedure to extract the tonal components.
The data embedding methodology modifies each component in a different manner. The residual component, xr, is modified using the standard embedding methodology described by (1) Information is embedded in the tonal components, xt, by shifting the relative position (frequency) of the tonals in an audio block. The tonal may be shifted since the human ear is unable to detect a difference in frequency within 3.6 Hz for frequencies below 500 Hz, and within 0.007 f for frequencies f>500 Hz. For frequencies in Layer 1, 1000 Hz to 4000 Hz, the frequencies may change from 7 to 28 Hz, respectively. The modification is usually limited from 5 to 20 Hz to ensure perceptual quality. The modifications to the length Nb block are generally performed on a 2 Nb or 4 Nb zero-padded FFT to guarantee a high frequency resolution. The frequencies are shifted in accordance with a pseudo-random pattern.
Once the frequencies have been modified, the sinusoidal signal synthesis methodology described in R. J. McAulay, T. F. Quatieri, “Speech analysis/synthesis based on a sinusoidal representation,” IEEE Trans. On Acoustics, Speech, and Signal Processing, vol. 34, no. 4, pp. 744-754, August, 1986, which is hereby incorporated by reference, is used to reconstruct the signal from the modified tonals. The McAulay methodology tracks frequencies from block to block to avoid discontinuities in the amplitudes and phases. The reconstruction algorithm locates a tonal in the next audio block closest to the tonal in the current block. If the closest tonal in the next block is within a pre-defined frequency range, the difference is assumed to represent the varying nature of audio. If the closest tonal in the next block is out of the frequency range, the tonal in the current block is assumed to have ceased. If a tonal appears in the next block that does not occur in the current block, a new tonal is flagged for tracking.
The amplitudes of tracked tonal components from block to block are matched using linear interpolation. A cubic interpolation function is used to match phases of tracked tonal components. The tonal component of the audio signal is then reconstructed by taking the inverse Fourier transform of the modified tonal amplitudes and phases.
The residual component, modified by the original audio data embedding algorithm, is added to the tonal component. The resulting signal has data embedded in both the tonal and non-tonal components.
The receiver recovers the embedded information by separating the tonal and residual components using the tonal detection algorithm. Data embedded in the residual component is recovered using the original data detection procedure. Information embedded in the tonal components is extracted by comparing the relative positions of the tonals with the pseudo-random patterns used by the data embedding algorithm. In particular, the information bit stream recovered depends on the match of the relative positions with the appropriate set of tonal patterns.
System
Referring now to FIG. 3 , a diagram of a system in accordance with an embodiment of the invention is shown. The system of FIG. 3 can in one embodiment be implemented in accordance with a computer, as will be described. The description of the system includes typical distortions and raw bit error rates at various points of the embedding, signal manipulation and data extraction chain.
The carrier signal 300 in the system is the audio or image host signal. The data embedding algorithm already described modulates the embedded data 302 (that is, the key or the watermark) with the carrier signal, as represented by block 304 . The raw embed rate for mono CD quality audio at this stage in the system is 252 bits/sec (504 bits/sec stereo audio). The raw embed rate does not take into account any reduction in bit rate required for error correction or synchronization. For a 512×512 grayscale image, the raw data rate at this point is 8192 bits. The embedded bit rate may be up to 3 times higher for color images.
The next stage in the system consists of error correction and synchronization algorithms, as represented by block 306 . Both are used for robustness under unknown channel conditions in one embodiment of the invention. Synchronization consists of repeatedly embedding a random pattern of bits known to the receiver. Much like the embedded data, the secure random pattern is based on encryption algorithms and may only be located by the appropriate audience. The synchronization bits reduce the raw bit rate by approximately 16%. Synchronization is essential to counteract the effects of the channel distortions that may delay, resize, rotate, crop, etc., the host signal. The receiver must be properly aligned with the embedded data for an accurate recovery of the information.
Two forms of error correction are employed by the data embedding system of FIG. 3 . One error correction mechanism is an averaging function. The raw data consists of binary values, i.e., 0's and 1's. Each value is embedded in the host signal such that the receiver detects a value in the range of zero to 1. Under lossless conditions, the receiver will detect a value exactly equal to 0 or 1 for each embedded data bit. However, channel distortions (see below) will modify the audio and cause damage to the embedded bits. The value of each bit will no longer be strictly 0 or 1. For example, a value of 0 may increase to 0.2 or 0.4. A value of 0.5 provides no information, as each bit is equally likely. Error correction via averaging works by repeating a data bit in more than one location in the audio and averaging the corresponding values at the receiver to make a decision. Averaging helps reduce errors introduced by the channel distortions. The typical number of bits used in the averaging process ranges from 2 to 6 in one embodiment. However, this reduces the bit rate from ½ to ⅙ the original rate, respectively. Typical effective embed rates after bit repetition for audio are 7-21 bits/sec for each band-pass combination (see Progress Report #8). This amounts to 7 to 105 bits/sec depending on channel conditions that are desired to survive.
Error correction via averaging works in conjunction with the second error correction mechanism: error control coding. Error control codes use sophisticated functions to increase the reliability of digital data transmission. Error control coding works most efficiently in environments with relatively low bit error rates. Thus, error correction via averaging is an essential preprocessing step to keep the bit errors low prior to error control coding. A commonly used error control code is a block code, e.g., Hamming and BCH, as described in S. Lin, D. J. Costello, Error Control Coding: Fundamentals and Applications, Prentice-Hall Inc., Englewood Cliffs, N.J., 1991, which is hereby incorporated by reference. A block code breaks an information stream into message blocks of size k. The message block of length k is then represented by a length n codeword, where n>k. A total of n-k redundant bits are added to each message to detect and correct errors in the message introduced by the noisy channel.
Once the embedding process is done, the audio or image passes through the communication channel, as represented by block 308 . The channel consists of any medium that may hold the audio or image data. The data may remain digital when transmitted through the channel, or may be converted to an analog form. For audio, this may include analog tapes, telephones, broadcast etc. For image media, the channel may include printer paper, newspapers, faxes, magazines, etc. Furthermore, any number of enhancements, coding representations, cropping, scaling, etc., may be applied to the host signal before reaching the receiver. A number of the degradation and distortions, e.g., telephone, printing, faxing, scanning, taping, can occur.
When the receiver obtains the host signal, the detection algorithm first synchronizes the received signal, as represented by block 310 . Synchronization may require a search over a range of delays, scales, and rotations, to properly align the received data. Once synchronized, the embedded data is extracted and processed by the error correction mechanisms. The values obtained for each repeated bit are combined and averaged to produce a bit estimate with reduced channel error. The BCH error control code is then applied to further reduce any bit errors, as represented by block 312 . This significantly decreases the chance of suffering stray bit errors. The resulting extracted data 314 thus includes bits that are properly assembled into the proper ASCII text or binary representation to reform the embedded information.
Computer
Referring finally to FIG. 4 , a diagram of a computer in conjunction with which embodiments of the invention may be practiced is shown. The computer comprises bus 400 , keyboard interface 401 , external memory 402 , mass storage device 403 and processor 404 . Bus 400 can be a single bus or a combination of multiple buses. Bus 400 can also comprise combinations of any buses. Bus 400 provides communication links between components in the computer. Keyboard controller 401 can be a dedicated device or can reside in another device such as a bus controller or other controller. Keyboard controller 401 allows coupling of a keyboard to the computer system and transmits signals from a keyboard to the computer system. External memory 402 can comprise a dynamic random access memory (DRAM) device, a static random access memory (SRAM) device, or other memory devices. External memory 402 stores information from mass storage device 403 and processor 404 for use by processor 404 . Mass storage device 403 can be a hard disk drive, a floppy disk drive, a CD-ROM device, or a flash memory device. Mass storage device 404 provides information to external memory 402 . Processor 404 can be a microprocessor and is capable of decoding and executing a computer program such as an application program or operating system with instructions from multiple instruction sets.
Multimedia data embedding has been described. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the following claims and equivalents thereof. | A method for embedding data into a media signal receives a media signal, divides the media signal into blocks of samples, and calculates a function of the samples in the blocks, including transformations of samples in the blocks to corresponding block values. A processor uses the block value to determine a factor for samples in the blocks to be multiplied by the samples so that when a data embedding function is evaluated for the block, an output of the data embedding function corresponds to a data value representing desired digital data embedded in the block. A compatible decoder extracts this embedded data from the media signal. The decoder divides the media signal into blocks of samples and calculates a function of the samples in the blocks, including transformations of samples in the blocks to corresponding block values. A processor processes the block value to evaluate a data embedding function to determine digital data embedded in the block. | Summarize the information, clearly outlining the challenges and proposed solutions. | [
"RELATED APPLICATION DATA This application is a continuation of U.S. application Ser.",
"No. 10/869,178, filed Jun. 15, 2004 (now U.S. Pat. No. 7,454,034), which is a continuation of U.S. application Ser.",
"No. 10/229,382, filed Aug. 26, 2002 (now U.S. Pat. No. 6,751,337), which is a continuation of U.S. application Ser.",
"No. 09/228,224, filed Jan. 11, 1999 (now U.S. Pat. No. 6,442,283).",
"These patents are incorporated herein by reference.",
"FIELD OF THE INVENTION This invention relates generally to multimedia data, and more particularly to multimedia data embedding.",
"BACKGROUND OF THE INVENTION With the increasingly popularity of multimedia-capable computers, and the digitalization of multimedia in general, the importance of multimedia data embedding has become more important.",
"In one type of multimedia data embedding, a key, also know as a watermark, is embedded into multimedia data, a process which is known as watermarking.",
"This allows questions of ownership of a given piece of multimedia data—which may be widely distributed by virtue of the Internet, for example—to be resolved, by attempting to decode the key from the multimedia data.",
"That is, by watermarking multimedia data, the data owner can determine whether a suspect piece of multimedia data is his or hers by determining whether the watermark is present in the suspect data.",
"For example, a record company, prior to making its music selections available on the Internet for widespread purchase and use, can first watermark the data representing a music selection.",
"If a site on the Internet is providing bootleg copies of the music selections, but claims that the copies are not in fact owned by the record company, the company can prove that they are indeed owned by it by showing that the watermark is present in the bootleg copies.",
"Therefore, watermarking has applicability to audio multimedia, as well as other types of multimedia, such as image and video multimedia.",
"SUMMARY The invention provides methods for embedding and decoding data embedded in media signals and related software implementations.",
"One aspect of the invention is a method for embedding data into a media signal.",
"The method receives a media signal, divides the media signal into blocks of samples, and calculates a function of the samples in the blocks, including transformations of samples in the blocks to corresponding block values.",
"A processor uses the block value to determine a factor for samples in the blocks to be multiplied by the samples so that when a data embedding function is evaluated for the block, an output of the data embedding function corresponds to a data value representing desired digital data embedded in the block.",
"Another aspect of the invention is a method of decoding data embedded in a media signal.",
"Like the embedder, the decoder divides the media signal into blocks of samples and calculates a function of the samples in the blocks, including transformations of samples in the blocks to corresponding block values.",
"A processor processes the block value to evaluate a data embedding function to determine digital data embedded in the block.",
"In one digital watermark embodiment, a decoder projects a digitally watermarked signal into a direction according to a key.",
"It applies a weighting function to the projected signal to compute a projected signal in which parts of the digitally watermarked signal that are more robust to distortion are weighted more than parts that are less robust to the distortion.",
"The method recovers embedded auxiliary data symbols from the projected signal by quantizing the projected signal to determine a binary symbol associated with a quantization of the projected signal.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a flowchart of a computer-implemented embedding method according to an embodiment of the invention;",
"FIG. 2 shows a flowchart of a computer-implemented decoding method according to an embodiment of the invention;",
"FIG. 3 shows a diagram of a system according to an embodiment of the invention;",
"and, FIG. 4 shows a diagram of a computer in conjunction with which embodiments of the invention may be practiced.",
"DETAILED DESCRIPTION OF THE INVENTION In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced.",
"These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the spirit or scope of the present invention.",
"The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.",
"Some portions of the detailed descriptions which follow are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory.",
"These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art.",
"An algorithm is here, and generally, conceived to be a self-consistent sequence of steps leading to a desired result.",
"The steps are those requiring physical manipulations of physical quantities.",
"Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated.",
"It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.",
"It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities.",
"Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the present invention, discussions utilizing terms such as “processing”",
"or “computing”",
"or “calculating”",
"or “determining”",
"or “displaying”",
"or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.",
"Methods Referring first to FIG. 1 , a computer-implemented embedding method according to an embodiment of the invention is shown.",
"That is, the method of FIG. 1 embeds a key p into multimedia data x, to generate watermarked data x′.",
"The computer-implemented method is desirably realized at least in part as one or more programs running on a computer—that is, as a program executed from a machine-readable medium such as a memory by a processor of a computer.",
"The programs are desirably storable on a machine-readable medium such as a floppy disk or a CD-ROM, for distribution and installation and execution on another computer, for example, over the Internet.",
"In block 100 , a vector x is received that represents multimedia data, such as audio, image, or video data;",
"the invention is not so limited.",
"In block 100 , x=[x (0) x (1) .",
"x ( N− 1)] and denotes a vector of N data samples.",
"In block 102 , a vector p is received that represents a pseudo-random sequence.",
"The vector p is the key or watermark that is to be embedded in the vector x. More specifically, p=[p (0) p (1) .",
"p ( N− 1)] and represents a cryptographically secure pseudo-random sequence generated from a one-way function and a key, as known within the art.",
"In block 104 , a vector x′ is generated, in which the vector p is embedded into the vector x. The vector x′ is the watermarked data, or the data into which the key has been embedded.",
"More specifically, the new data vector x′=[x ′(0) x ′(1) .",
"x ′( N− 1)] is generated by adding a second vector to the data vector x producing the new data vector x′=x+aq (1) where a is a perception-based scaling factor and vector q is a perceptually weighted pseudo-random sequence.",
"Both components a and q are perception-based to insure that x and x′ are indistinguishable to the human audio or visual systems for audio and image/video data, respectively.",
"The computation of q and a depend on the pseudo-random sequence p and a weighting mechanism as described below.",
"Note that the new data vector in (1) may be represented by x ′ = x + ∑ n = 0 N - 1 a n q n where N orthogonal pseudo-random sequences q n are employed.",
"Each term a n q n is used to carry one bit of information.",
"Referring next to FIG. 2 , a flowchart of a computer-implemented decoding method is shown.",
"That is, the method of FIG. 2 generates a key vector p as embedded from a multimedia vector x′, as such a multimedia vector x′ has been generated in accordance with the method of FIG. 1 .",
"Like the method of FIG. 1 , the computer-implemented method of FIG. 2 is desirably realized at least in part as one or more programs running on a computer—that is, as a program executed from a machine-readable medium such as a memory by a processor of a computer.",
"The programs are desirably storable on a machine-readable medium such as a floppy disk or a CD-ROM, for distribution and installation and execution on another computer, for example, over the Internet.",
"In block 200 , a multimedia vector x′ is first received, from in which a key p has been embedded into a multimedia vector x. In block 202 , the key p is decoded from the vector x′.",
"To decode the embedded data, a scaled inner product between the new data vector x′ and the pseudo-random sequence p is computed 1 T ∑ i = 0 N - 1 p ( i ) x ′ ( i ) w ( i ) = 1 T ∑ i = 0 N - 1 p ( i ) x ( i ) + aq ( i ) w ( i ) = 1 T ∑ i = 0 N - 1 p ( i ) x ( i ) w ( i ) + a T ∑ i = 0 N - 1 p ( i ) q ( i ) w ( i ) ( 2 ) where w is a vector of weights as described below.",
"The value of T dictates the quantization step of the algorithm and is dependent on the weighting-mechanism employed.",
"The first term on the right hand side of (2) is referred to as the residual.",
"It represents the projection of the original data sequence x onto the pseudo-random direction p weighted by w. The second term on the right hand side of (2) is the projection of the shaped pseudo-random sequence q with the pseudo-random direction p weighted by w. As described in (1), the second term carries the embedded information.",
"The residual R R = 1 T ∑ i = 0 N - 1 p ( i ) x ( i ) w ( i ) ( 3 ) is known.",
"Using this knowledge, a variable d is defined where d=B−R and B = { 0 if b = 1 1 / 2 if b = 0 and R >",
"0 - 1 / 2 if b = 0 and R <",
"0 where b is the data bit to embed.",
"The variable a in (1) is computed as a = dT ∑ i = 0 N - 1 p ( i ) q ( i ) w ( i ) ( 4 ) Substituting (3) and (4) into (2), the embedded data can be recovered without error in an environment without distortion.",
"In at least some embodiments of the invention, factors to consider when embedding data in audio, the weighting function w, and the shaped pseudo-random sequence q are described below.",
"Audio Data Hiding Considerations The audio data hiding algorithm works by making perceptually insignificant modifications to the audio samples.",
"The audio signal is modified in blocks of size Nb, i.e., Nb consecutive samples of the audio are processed at the same time.",
"In one implementation, the blocks are non-overlapping.",
"However, overlapping blocks may be used.",
"The data embedding algorithm described above is computed in the discrete cosine transform (DCT) domain for audio signals.",
"Due to the presence of efficient Fast Fourier Transform methodologies known in the art, Nb is typically selected as a power of 2, e.g., Nb=1024.",
"The size of the block is controlled by several factors.",
"Since audio characteristics may change rapidly, the block size should be small to keep modifications localized in time.",
"Smaller block sizes are also preferred during the decoding process during synchronization.",
"However, the block size should be large enough to provide a high frequency resolution.",
"The DCT frequency resolution is computed as fd = fs 2 Nb where fs is the sampling frequency of the audio signal.",
"For Nb=1024 and fs=44100 Hz, the frequency resolution is fd=21.53 Hz.",
"A length Nb block of audio samples produces Nb DCT coefficients.",
"In the standard implementation, the DCT spectrum is generally segmented into smaller subbands.",
"In particular, a subset of length N<Nb of the DCT coefficients is used to embed each data bit as described in (1).",
"Each subband may consist of a different number of DCT coefficients.",
"For example, the spectrum may be segmented into three bands in the frequency ranges of 1000-4000 Hz, 4000-8000 Hz, and 8000-15000 Hz.",
"The audio data embedding procedure also includes the MPEG psychoacoustic masking model 1 or 2 , as known in the art, for checking tolerable error levels.",
"The MPEG masking model is used to verify the perceptual quality of (1).",
"Components of the embedded data signal may be scaled or clipped to meet the requirements of the masking model.",
"The Pseudo-Random Sequence In one embodiment, one or two random keys x 1 and x 2 (i.e., seeds) are used from which a pseudo-random sequence p can be generated, by using a suitable pseudo-random sequence generator, such as described in R. Rivest, “Cryptography,” pp. 717-755, in J. van Leeuwen (ed.), Handbook of Theoretical Computer Science, Vol. 1, Ch.",
"13, MIT Press, Cambridge, Mass.",
", 1990, which is hereby incorporated by reference.",
"Only the first key, x 1 , is used for most data embedding applications.",
"The second key, x 2 , is required for watermarking audio.",
"It is used to make counterfeiting very difficult.",
"Popular generators include RSA, Rabin, Blum/Micali, and Blum/Blum/Shub, as known in the art, and as described in S. Goldwasser, M. Bellare, “Lecture notes on cryptography”, preprint, July 1996: http://www-cse.",
"ucsd.edu/users/mihir/papers/crypto-papers.",
"html.",
"With the proper keys, the embedded data may be extracted.",
"Without the key(s), the data hidden in the signal is statistically undetectable and impossible to recover.",
"Note that classical maximal length pseudo noise sequence (i.e., m-sequence) generated by linear feedback shift registers are not used to generate a pseudo-random sequence.",
"Sequences generated by shift registers are cryptographically insecure: one can solve for the feedback pattern (i.e., the keys) given a small number of output bits p. The noise-like sequence p can be used to derive the actual watermark hidden into the audio signal or control the operation of the watermarking algorithm, e.g., determine the location of samples that may be modified.",
"The key x 1 is author dependent.",
"A second key, x 2 , is signal dependent.",
"The key x 1 is the key assigned to (or chosen by) the author.",
"Key x 2 is computed from the audio signal when the author wishes to watermark the audio signal.",
"It is computed from the signal using a one-way hash function.",
"For example, the tolerable error levels supplied by masking models are hashed to a key x 2 .",
"Any one of a number of well-known secure one way hash functions may be used to compute x 2 , including RSA, MD4, and SHA, as known in the art.",
"MD4 is specifically described in R. Rivest, “The MD4 message digest algorithm”, pp. 303-311 in Advances in Cryptology, CRYPTO 92, Springer, Tokyo, 1991, which is hereby incorporated by reference;",
"SHA is specifically described in National Institute of Standards and Technology (NIST), Secure Hash Standard, NIST FIPS Pub.",
"180-1, April 1995, which is also hereby incorporated by reference.",
"For example, the Blum/Blum/Shub pseudo-random generator uses the one way function y=g_n(x)=x^2 mod n where n=pq for primes p and q so that p=q=3 mod 4.",
"In at least some embodiments, generating x or y from partial knowledge of y is computationally infeasible for the Blum/Blum/Shub generator.",
"A QR orthogonal-triangular decomposition operation is performed on the pseudo-random sequences before they are employed by the data embedding algorithm.",
"A typical pseudo-random sequence generator creates a sequence of samples with values ranging from −1 to +1.",
"The relative magnitudes of samples in the sequence may be on the order of 10^6, leading to spiking and poor weighting characteristics.",
"A QR decomposition is employed to maintain a relative magnitude in the samples on the order of 0.9 to 1.1.",
"The Weighting Function A number of functions to weight the pseudo-random sequence p for robustness and perceptual quality can be been employed in accordance with different embodiments of the invention.",
"The weighting coefficients w are generally computed as a function of the data coefficients x. One method to generate the weighting values includes computing the average of the absolute value of the data coefficients about a length Nf interval w ( i ) = 1 Nf ∑ k = - * Nf - 1 ) / 2 ( Nf - 1 ) / 2 x ( i - k ) The value of Nf is kept small to keep the averaging localized, e.g., Nf=13.",
"Out-of-band DCT coefficients were used at the boundaries of the averaging interval.",
"In other embodiments of the invention, the DCT subband is segmented into critical bands as described by the MPEG psychoacoustic model 1 , known within the art.",
"Each subband consists of Nc critical bands.",
"The varying length critical bands increase in size with frequency.",
"Several techniques to compute the weight wi for each critical band were employed.",
"Note that each wi is a vector of the same length as each critical band.",
"In some embodiments, the weighting function is computed independently for each critical band.",
"These include the one-norm, w ( i ) = w 1 ( i ) = ∑ k ∈ CB x ( k ) two-norm, w ( i ) = w 2 ( i ) = ( ∑ k ∈ CB x ( k ) 2 ) 1 / 2 and infinity-norm w ( i )= w∞ ( i )=max| x ( k )| Each of the weights is constant over its corresponding critical band.",
"The purpose of the weighting function is to approximate the relative tolerable error level for each DCT component and the corresponding accuracy at the receiver.",
"For example, a weight for a tonal critical band may be large.",
"However, the weight relative to the tonal is small.",
"This is designed to emulate coding algorithms which generally introduce a smaller relative error in tonal components than in non-tonal components.",
"As the weight estimate is required at the receiver, the weighting function is required to be robust to many distortions.",
"The aforementioned weighting functions are designed to perform well in terms of relative error before and after distortions to the host audio signal.",
"In most cases the value of the weighting function wi depends on several data samples.",
"The Shaped Pseudo-Random Sequence The second term in the data embedding methodology (1) includes two components: a and q. The a term was defined in (4).",
"The shaped pseudo-random sequence, q, may be computed in a variety of manners from the secure pseudo-random sequence p. In one embodiment, the shaped pseudo-random sequence is defined as q=p*w where w consists of a weighting function defined in the previous section and * represents a component-by-component multiplication.",
"As a result, the modification to the original data sequence is a scaled version of the pseudo-random sequence shaped by the weights.",
"A second approach employs a finer resolution in the modification by defining the shaped pseudo-random sequence as q=p*|x| (5) In this case, the pseudo-random sequence is shaped by the absolute value of the data it is modifying.",
"The finer resolution in this case is due to the fact that the weights wi in the previous section are constant over multiple samples, i.e., the critical band.",
"The modification in is performed at an individual sample level.",
"The previously described shaping techniques for the pseudo-random sequence only take into account frequency shaping, in at least some embodiments of the invention.",
"To insure that the data embedding algorithm avoids pre- and post-echo distortions, a temporal shaping component is introduced.",
"Recall that the embedding methodology is computed in the frequency domain.",
"Let xt denote the data block in the time domain.",
"Note that the length of the time data vector is Nb, i.e., the same length as the DCT block.",
"To account for temporal shaping, the envelope of the data signal in the time domain is generated.",
"First the DCT of the absolute value of the data in the time domain is computed X=dct (| xt |) A second DCT signal X′ is generated by retaining only the first K low frequency coefficients of X X ′ = { X ( i ) if 0 ≤ i ≤ K 0 otherwise Typically, 6<K<10 depending on the desired amount of smoothing of the envelope.",
"An inverse DCT computation is performed on X′ generating a smoothed envelope m of the data signal.",
"To generate q, an intermediate signal q′ is computed as described in (5) q′=p*|x| The time-domain representation, qt′, of the pseudo-random sequence q′ is computed by qt′=idct ( q ′) and multiplied by the envelope m, generating a temporally-shaped pseudo-random sequence qt″=m*qt′ (6) The DCT of the temporally-shaped pseudo-random sequence is computed, resulting in the final shaped pseudo-random sequence q=dct ( qt ″) The value of a is then computed as described by (4).",
"Note that the pseudo-random sequence p is shaped in both the frequency and time domains to increase the perceptual quality of the embedded data.",
"In one particular embodiment, a window h is introduced in (6).",
"In particular, the window is introduced to generate a temporally-shaped and windowed pseudo-random sequence qt″=h*m*qt′ The other calculations are not affected.",
"A rectangular window introduces an audible blocking effect in some audio signals.",
"A shaped window h that tapers off near the beginning and ending of the block prevents the blocking noise.",
"Gaussian and trapeziodal windows, as known in the art, are employed by the data embedding methodology.",
"A different approach to compute q based on coding error is now described.",
"In this embodiment, the coded audio signal xc at the target bit rate and coding algorithm is generated and used to obtain the coding error e=x−xc The shaped pseudo-random sequence q is computed as q=p*e The approach exploits perceptual characteristics of most current audio coding algorithms.",
"In particular, the coding error e generated by popular algorithms, e.g., Dolby's AC-3 and MPEC, as known in the art, is typically perceptually shaped.",
"In a related embodiment, the value of a described in (4) is modified to take into account coding error.",
"Several different values of a are computed according to a = b dT ∑ i = 0 N - 1 p ( i ) q ( i ) w ( i ) where 0<<b<1 is employed to tweak to the value of a to the best value for the target bit rate.",
"Each is tested by coding the embedded audio algorithm and recovering the embedded data bit.",
"The best a is selected.",
"Tonal Detection Tonal (harmonic) and non-tonal (residue) components in an audio signal have different perceptual characteristics based on the masking properties of the human auditory system.",
"For example, the amplitude of non-tonal and low level noise components in an audio signal may be modified in the range of 50-100% without a perceptually significant change to the audio.",
"Perceptual changes in tonal components, however, may sometimes be detected after only a 10\\% change in amplitude.",
"The strength of embedded data may be limited by maximum allowable changes to the tonal components.",
"To enhance the audio data hiding algorithm, a tool to detect the tonal components in audio signals was developed.",
"By separating tonal and non-tonal components, the data embedding algorithm is able to maximize the strength of each component independently.",
"The tonal components in an audio signal are identified using a harmonic analysis technique as described in D. J. Thomson, “Spectrum estimation and harmonic analysis,” Proceedings of the IEEE, vol.",
"70, no. 9, pp. 1055-1096, September, 1982, which is hereby incorporated by reference.",
"The analysis provides an accurate estimate of the location (frequency), amplitude, and phase of harmonic components in the audio.",
"As described in the following section, this information may be used to change the weighting function.",
"It may also used in an alternative data hiding.",
"The technique described in Thomson analyzes harmonic components in an audio signal by expanding the audio signal in terms of a set of orthogonal windows called prolate sequences.",
"The expansion is followed by a statistical F-test to determine whether a tonal component exists at a particular frequency.",
"The harmonic analysis is performed on segments of Nb audio samples as described in the previous section.",
"The audio segment is multiplied (windowed) by a set of K prolate sequences.",
"A zero-padded discrete Fourier transform of each windowed data sequence is then computed.",
"The windowing provides K different estimates of the spectrum based on the K different prolate windows.",
"Zero-padding is used to prevent circular wrapping and provide a high level of frequency resolution.",
"Typically the sequence is zero-padded to 2 Nb or 4 Nb The harmonic mean at each frequency is then computed followed by an F-test statistic is then computed.",
"The F-value at each frequency is a measure of the ratio of the estimate of the magnitude of the harmonic at that frequency to that of the non-tonal part of the spectrum.",
"If a tonal exists at a particular frequency, the F-value will be large.",
"A small F-value indicates that the component is non-tonal.",
"The frequencies corresponding to tonals in the audio are obtained by finding peaks in the F-statistics.",
"The frequency, amplitude, and phase of each tonal component are then provided to the audio data embedding algorithm.",
"The process is repeated on each length Nb segment of the audio.",
"Tonal Weighting The tonal detection methodology provides the position (frequency) of each tonal component in a length Nb block of audio.",
"With the tonal detection and audio data embedding algorithms synchronized in time and employing the same number of audio samples Nb, the data embedding algorithm uses the detected tonals occurring in each frequency band to modify the weighting function.",
"Weights corresponding to tonal components (and frequency components near the tonal) are scaled differently than non-tonal components, let z denote the set of tonal indexes returned by the tonal detection algorithm.",
"A modified version x′ of the data x is generated such that x ′ ( k ) = { Bx ( k ) if k ∈ z x ( k ) otherwise where 0<B<1 is a scaling value for tonal components.",
"Parameter q is computed as described earlier using x′ in place of x, i.e., q′=p*|x′| As a result, the tonal and non-tonal components of the data have a different effect on the computation of q through the use of the parameter B. This allows the algorithm to modify the amplitude of tonal components, e.g., by +/−10%, differently than non-tonal components, e.g, by +/−50%.",
"The same tonal detection algorithm is employed by the receiver to generate the appropriate weights and recover the embedded information.",
"Tonal Shifting An alternative embedding scheme employing tonal detection is now described.",
"The embedding methodology first separates the original audio signal into a tonal component and a residual (non-tonal) component x=x r +x t This embodiment uses the frequency, amplitude, and phase information provided by the tonal detection procedure to extract the tonal components.",
"The data embedding methodology modifies each component in a different manner.",
"The residual component, xr, is modified using the standard embedding methodology described by (1) Information is embedded in the tonal components, xt, by shifting the relative position (frequency) of the tonals in an audio block.",
"The tonal may be shifted since the human ear is unable to detect a difference in frequency within 3.6 Hz for frequencies below 500 Hz, and within 0.007 f for frequencies f>500 Hz.",
"For frequencies in Layer 1, 1000 Hz to 4000 Hz, the frequencies may change from 7 to 28 Hz, respectively.",
"The modification is usually limited from 5 to 20 Hz to ensure perceptual quality.",
"The modifications to the length Nb block are generally performed on a 2 Nb or 4 Nb zero-padded FFT to guarantee a high frequency resolution.",
"The frequencies are shifted in accordance with a pseudo-random pattern.",
"Once the frequencies have been modified, the sinusoidal signal synthesis methodology described in R. J. McAulay, T. F. Quatieri, “Speech analysis/synthesis based on a sinusoidal representation,” IEEE Trans.",
"On Acoustics, Speech, and Signal Processing, vol.",
"34, no. 4, pp. 744-754, August, 1986, which is hereby incorporated by reference, is used to reconstruct the signal from the modified tonals.",
"The McAulay methodology tracks frequencies from block to block to avoid discontinuities in the amplitudes and phases.",
"The reconstruction algorithm locates a tonal in the next audio block closest to the tonal in the current block.",
"If the closest tonal in the next block is within a pre-defined frequency range, the difference is assumed to represent the varying nature of audio.",
"If the closest tonal in the next block is out of the frequency range, the tonal in the current block is assumed to have ceased.",
"If a tonal appears in the next block that does not occur in the current block, a new tonal is flagged for tracking.",
"The amplitudes of tracked tonal components from block to block are matched using linear interpolation.",
"A cubic interpolation function is used to match phases of tracked tonal components.",
"The tonal component of the audio signal is then reconstructed by taking the inverse Fourier transform of the modified tonal amplitudes and phases.",
"The residual component, modified by the original audio data embedding algorithm, is added to the tonal component.",
"The resulting signal has data embedded in both the tonal and non-tonal components.",
"The receiver recovers the embedded information by separating the tonal and residual components using the tonal detection algorithm.",
"Data embedded in the residual component is recovered using the original data detection procedure.",
"Information embedded in the tonal components is extracted by comparing the relative positions of the tonals with the pseudo-random patterns used by the data embedding algorithm.",
"In particular, the information bit stream recovered depends on the match of the relative positions with the appropriate set of tonal patterns.",
"System Referring now to FIG. 3 , a diagram of a system in accordance with an embodiment of the invention is shown.",
"The system of FIG. 3 can in one embodiment be implemented in accordance with a computer, as will be described.",
"The description of the system includes typical distortions and raw bit error rates at various points of the embedding, signal manipulation and data extraction chain.",
"The carrier signal 300 in the system is the audio or image host signal.",
"The data embedding algorithm already described modulates the embedded data 302 (that is, the key or the watermark) with the carrier signal, as represented by block 304 .",
"The raw embed rate for mono CD quality audio at this stage in the system is 252 bits/sec (504 bits/sec stereo audio).",
"The raw embed rate does not take into account any reduction in bit rate required for error correction or synchronization.",
"For a 512×512 grayscale image, the raw data rate at this point is 8192 bits.",
"The embedded bit rate may be up to 3 times higher for color images.",
"The next stage in the system consists of error correction and synchronization algorithms, as represented by block 306 .",
"Both are used for robustness under unknown channel conditions in one embodiment of the invention.",
"Synchronization consists of repeatedly embedding a random pattern of bits known to the receiver.",
"Much like the embedded data, the secure random pattern is based on encryption algorithms and may only be located by the appropriate audience.",
"The synchronization bits reduce the raw bit rate by approximately 16%.",
"Synchronization is essential to counteract the effects of the channel distortions that may delay, resize, rotate, crop, etc.",
", the host signal.",
"The receiver must be properly aligned with the embedded data for an accurate recovery of the information.",
"Two forms of error correction are employed by the data embedding system of FIG. 3 .",
"One error correction mechanism is an averaging function.",
"The raw data consists of binary values, i.e., 0's and 1's.",
"Each value is embedded in the host signal such that the receiver detects a value in the range of zero to 1.",
"Under lossless conditions, the receiver will detect a value exactly equal to 0 or 1 for each embedded data bit.",
"However, channel distortions (see below) will modify the audio and cause damage to the embedded bits.",
"The value of each bit will no longer be strictly 0 or 1.",
"For example, a value of 0 may increase to 0.2 or 0.4.",
"A value of 0.5 provides no information, as each bit is equally likely.",
"Error correction via averaging works by repeating a data bit in more than one location in the audio and averaging the corresponding values at the receiver to make a decision.",
"Averaging helps reduce errors introduced by the channel distortions.",
"The typical number of bits used in the averaging process ranges from 2 to 6 in one embodiment.",
"However, this reduces the bit rate from ½ to ⅙ the original rate, respectively.",
"Typical effective embed rates after bit repetition for audio are 7-21 bits/sec for each band-pass combination (see Progress Report #8).",
"This amounts to 7 to 105 bits/sec depending on channel conditions that are desired to survive.",
"Error correction via averaging works in conjunction with the second error correction mechanism: error control coding.",
"Error control codes use sophisticated functions to increase the reliability of digital data transmission.",
"Error control coding works most efficiently in environments with relatively low bit error rates.",
"Thus, error correction via averaging is an essential preprocessing step to keep the bit errors low prior to error control coding.",
"A commonly used error control code is a block code, e.g., Hamming and BCH, as described in S. Lin, D. J. Costello, Error Control Coding: Fundamentals and Applications, Prentice-Hall Inc., Englewood Cliffs, N.J., 1991, which is hereby incorporated by reference.",
"A block code breaks an information stream into message blocks of size k. The message block of length k is then represented by a length n codeword, where n>k.",
"A total of n-k redundant bits are added to each message to detect and correct errors in the message introduced by the noisy channel.",
"Once the embedding process is done, the audio or image passes through the communication channel, as represented by block 308 .",
"The channel consists of any medium that may hold the audio or image data.",
"The data may remain digital when transmitted through the channel, or may be converted to an analog form.",
"For audio, this may include analog tapes, telephones, broadcast etc.",
"For image media, the channel may include printer paper, newspapers, faxes, magazines, etc.",
"Furthermore, any number of enhancements, coding representations, cropping, scaling, etc.",
", may be applied to the host signal before reaching the receiver.",
"A number of the degradation and distortions, e.g., telephone, printing, faxing, scanning, taping, can occur.",
"When the receiver obtains the host signal, the detection algorithm first synchronizes the received signal, as represented by block 310 .",
"Synchronization may require a search over a range of delays, scales, and rotations, to properly align the received data.",
"Once synchronized, the embedded data is extracted and processed by the error correction mechanisms.",
"The values obtained for each repeated bit are combined and averaged to produce a bit estimate with reduced channel error.",
"The BCH error control code is then applied to further reduce any bit errors, as represented by block 312 .",
"This significantly decreases the chance of suffering stray bit errors.",
"The resulting extracted data 314 thus includes bits that are properly assembled into the proper ASCII text or binary representation to reform the embedded information.",
"Computer Referring finally to FIG. 4 , a diagram of a computer in conjunction with which embodiments of the invention may be practiced is shown.",
"The computer comprises bus 400 , keyboard interface 401 , external memory 402 , mass storage device 403 and processor 404 .",
"Bus 400 can be a single bus or a combination of multiple buses.",
"Bus 400 can also comprise combinations of any buses.",
"Bus 400 provides communication links between components in the computer.",
"Keyboard controller 401 can be a dedicated device or can reside in another device such as a bus controller or other controller.",
"Keyboard controller 401 allows coupling of a keyboard to the computer system and transmits signals from a keyboard to the computer system.",
"External memory 402 can comprise a dynamic random access memory (DRAM) device, a static random access memory (SRAM) device, or other memory devices.",
"External memory 402 stores information from mass storage device 403 and processor 404 for use by processor 404 .",
"Mass storage device 403 can be a hard disk drive, a floppy disk drive, a CD-ROM device, or a flash memory device.",
"Mass storage device 404 provides information to external memory 402 .",
"Processor 404 can be a microprocessor and is capable of decoding and executing a computer program such as an application program or operating system with instructions from multiple instruction sets.",
"Multimedia data embedding has been described.",
"Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown.",
"This application is intended to cover any adaptations or variations of the present invention.",
"Therefore, it is manifestly intended that this invention be limited only by the following claims and equivalents thereof."
] |
RELATED APPLICATION
[0001] This application is a divisional application of the U.S. patent application Ser. No. 11/303,408, filed on Dec. 16, 2005, which claims the benefit of Korean patent application number 10-2005-0024543, filed on Mar. 24, 2005, in the Korean Intellectual Property Office, the contents of which applications are incorporated herein in their entirety by reference.
FIELD OF THE INVENTION
[0002] The invention relates to field-effect transistors (FETs) on semiconductor substrates and manufacturing methods thereof, and, more particularly, to a FET having a round-shaped, i.e., circular, nano-wire channel and a fabricating method thereof.
DESCRIPTION OF THE RELATED ART
[0003] As applications for semiconductor devices expand, highly-integrated and/or high-speed semiconductor devices are increasingly in demand. As integration density of semiconductor devices increases, a design rule becomes smaller. As a result of the decreasing design rule, a channel length and a channel width of a field effect transistor (FET) similarly decrease. A decrease in channel length may result in a short channel effect. A decrease in channel width may result in a narrow channel effect. The short channel effect may significantly influence potential in a source/drain region upon a channel region. The narrow channel width effect may generally increase a threshold voltage. However, in the case of a device using a STI (Shallow Trench Isolation), a channel width that is too narrow may decrease a threshold voltage. This is referred to as an inverse narrow width effect. In an attempt to prevent generation of the short channel effect and/or the narrow channel effect, various FETs having new structures have been proposed.
[0004] Recently, efforts have been made, particularly in the area of nano-size technology in the semiconductor field, to increase drive current of a transistor and decrease the short channel effect. Conventionally, several methods have been used in an effort to achieve these results. Examples of these attempts include a recessed channel array transistor (RCAT), a fin-type FET (FinFET), and gate-all-around transistor (GAT) technologies.
[0005] Each of these conventional devices and the corresponding methods of fabricating these devices, suffer from one of more disadvantages. For example, these conventional devices are limited in an ability to perform fast operations. Moreover, the number of spaced channel layers in these conventional devices is limited due to fabrication limitations, e.g., with respect to an etching depth that can be achieved during dry etching.
SUMMARY OF THE INVENTION
[0006] The present invention is therefore directed to a FET having one or more nano-wire channels and a method of manufacturing the FET, which substantially overcome one or more of the drawbacks due to the limitations and disadvantages of the prior art.
[0007] According to a first aspect, the invention is directed to a method of fabricating a field effect transistor (FET). According to the method, source and drain regions are formed on a semiconductor substrate. A plurality of preliminary channel regions are formed coupled between the source and drain regions. The preliminary channel regions are etched, and the etched preliminary channel regions are annealed to form FET channel regions, the FET channel regions having a substantially circular cross-sectional shape.
[0008] In one embodiment, the preliminary channel regions have a substantially rectangular cross-sectional shape. In one embodiment, the preliminary channel regions have corners in cross-section.
[0009] In one embodiment, the etching is performed in an atmosphere containing one or both of HCl and H 2 . In one embodiment, a ratio of a flow rate of HCl to a flow rate of H 2 is from 3:7 to 1:1. In one particular embodiment, the ratio of flow rate of HCl to flow rate of H 2 is 3:5.
[0010] In one embodiment, the etching is performed at a temperature of 600 to 900 degrees C. The etching can be performed for a period of 1 to 120 seconds. The etching can be performed at a pressure of 10 to 100 Torr.
[0011] In one embodiment, the annealing is performed in an atmosphere containing H 2 . The annealing can be performed with H 2 introduced at a flow rate of 1 to 500 seem. The annealing can be performed at a temperature of 600 to 900 degrees C., and, more particularly, at a temperature of 810 degrees C. The annealing can be performed for a period of 10 to 800 seconds, and, more particularly, for a period of 500 seconds.
[0012] In one embodiment, the method further comprises, after forming the preliminary channel regions, cleaning the structure to remove oxide from the structure. The cleaning can be performed in an atmosphere containing at least one of H 2 , Ar and He. The cleaning can be performed at a temperature of 600 to 900 degrees C. The cleaning can be performed at a gas flow rate of 1 to 500 sccm. The cleaning can be performed for a period of 1 to 5 minutes. The cleaning can be performed at a pressure of 0.1 to 10 Torr. In one embodiment, forming the plurality of preliminary channel regions comprises forming a channel layer and a sacrificial layer vertically adjacent to the channel layer. In one embodiment, the channel layer and the sacrificial layer are formed epitaxially. In one embodiment, the channel layer is a silicon layer. In one embodiment, the sacrificial layer is a SiGe layer.
[0013] In one embodiment, forming the plurality of preliminary channel regions further comprises trimming the channel layer to a desired dimension such that a front surface of at least one of the preliminary channel regions is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions. The trimming can included etching the channel layer. Etching the channel layer can include a chemical dry etch.
[0014] In one embodiment, forming the plurality of preliminary channel regions further comprises forming a mask layer over the channel layer and sacrificial layer, the mask layer defining a region separating the FET channel regions.
[0015] In one embodiment, forming the plurality of preliminary channel regions comprises forming a plurality of sacrificial layers vertically adjacent to a channel layer. The sacrificial layers can comprise SiGe. An upper sacrificial layer can have a lower concentration of germanium than a lower sacrificial layer.
[0016] In one embodiment, the method further comprises purging a process chamber between etching the preliminary channel regions and annealing the etched preliminary channel regions.
[0017] In one embodiment, the etching and annealing steps are performed at least two times. In one embodiment, the method further comprises purging steps between a prior etching step and a next annealing step.
[0018] In one embodiment, the method further comprises forming a gate dielectric layer on the FET channel regions.
[0019] In one embodiment, the method further comprises forming a gate surrounding the FET channel regions. the gate can include polysilicon. Also, the gate comprises metal.
[0020] According to another aspect, the invention is directed to a method of fabricating a field effect transistor (FET). According to the method, at least one channel layer and at least one sacrificial layer are alternately stacked on a substrate. Source and drain regions are formed on the substrate coupled to the alternately stacked at least one channel layer and at least one sacrificial layer. The alternately stacked at least one channel layer and at least one sacrificial layer are patterned to form a plurality of preliminary channel regions coupled between the source and drain regions. A remaining portion of the at least one sacrificial layer is removed. The preliminary channel regions are etched, the etched preliminary channel regions are annealed to form FET channel regions, the FET channel regions having a substantially circular cross-sectional shape.
[0021] In one embodiment, the preliminary channel regions have a substantially rectangular cross-sectional shape. In one embodiment, the preliminary channel regions have corners in cross-section.
[0022] In one embodiment, the at least one channel layer and the at least one sacrificial layer are formed epitaxially.
[0023] In one embodiment, the at least one channel layer is a silicon layer. In one embodiment, the at least one sacrificial layer is a SiGe layer.
[0024] In one embodiment, forming the plurality of preliminary channel regions further comprises trimming the at least one channel layer to a desired dimension such that a front surface of at least one of the preliminary channel regions is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions. In one embodiment, the trimming comprises etching the at least one channel layer. Etching the at least one channel layer can include a chemical dry etch.
[0025] In one embodiment, forming the plurality of preliminary channel regions further comprises forming a mask layer over the at least one channel layer and at least one sacrificial layer, the mask layer defining a region separating the FET channel regions.
[0026] In one embodiment, forming the plurality of preliminary channel regions comprise forming a plurality of sacrificial layers vertically adjacent to the channel layer.
[0027] The sacrificial layers can comprise SiGe. In one embodiment, an upper sacrificial layer has a lower concentration of germanium than a lower sacrificial layer.
[0028] In one embodiment, the method further comprises purging a process chamber between etching the preliminary channel regions and annealing the etched preliminary channel regions.
[0029] In one embodiment, the method further comprises forming a gate dielectric layer on the FET channel regions.
[0030] In one embodiment, the method further comprises forming a gate surrounding the FET channel regions. The gate can include polysilicon. Also, the gate can include metal.
[0031] According to another aspect, the invention is directed to a method of fabricating a field effect transistor (FET). According to the method, source and drain regions are formed on a semiconductor substrate. A plurality of preliminary channel regions are formed coupled between the source and drain regions. Forming the plurality of preliminary channel regions comprises: (i) forming a channel layer and a sacrificial layer vertically adjacent to the channel layer, and (ii) trimming the channel layer to a desired dimension such that a front surface of at least one of the preliminary channel regions is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions. The preliminary channel regions are etched, and the etched preliminary channel regions are annealed to form FET channel regions, the FET channel regions having a substantially circular cross-sectional shape.
[0032] In one embodiment, the preliminary channel regions have a substantially rectangular cross-sectional shape. In one embodiment, the preliminary channel regions have corners in cross-section.
[0033] In one embodiment, the method further comprises, after forming the preliminary channel regions, cleaning the structure to remove oxide from the structure.
[0034] In one embodiment, the channel layer and the sacrificial layer are formed epitaxially.
[0035] The channel layer can be a silicon layer, and the sacrificial layer can be a SiGe layer.
[0036] In one embodiment, the trimming comprises etching the channel layer. Etching the channel layer can include a chemical dry etch.
[0037] In one embodiment, forming the plurality of preliminary channel regions comprises forming a plurality of sacrificial layers vertically adjacent to the channel layer. The sacrificial layers can include SiGe. An upper sacrificial layer can have a lower concentration of germanium than a lower sacrificial layer.
[0038] In one embodiment, the method further comprises purging a process chamber between etching the preliminary channel regions and annealing the etched preliminary channel regions.
[0039] In one embodiment, the method further comprises forming a gate dielectric layer on the FET channel regions.
[0040] In one embodiment, the method further comprises forming a gate surrounding the FET channel regions. In one embodiment, the gate comprises polysilicon. In one embodiment, the gate comprises metal.
[0041] According to another aspect, the invention is directed to a method of fabricating a field effect transistor (FET). According to the method, source and drain regions are formed on a semiconductor substrate. A preliminary channel region is formed coupled between the source and drain regions, forming the preliminary channel region comprising: (i) forming a channel layer and a sacrificial layer vertically adjacent to the channel layer, and (ii) trimming the channel layer to a desired dimension such that a front surface of the preliminary channel region is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions. A remaining portion of the sacrificial layer is removed. The trimmed channel layer is etched, and the etched channel layer is annealed to form a FET channel region, the FET channel region having a substantially circular cross-sectional shape.
[0042] According to another aspect, the invention is directed to a method of fabricating a field effect transistor (FET). According to the method, source and drain regions are formed on a semiconductor substrate. A preliminary channel region is formed coupled between the source and drain regions, forming the preliminary channel region comprising forming a channel layer and a sacrificial layer vertically adjacent to the channel layer. A remaining portion of the sacrificial layer is removed. The preliminary channel region is etched, and the etched preliminary channel region is annealed to form a FET channel region, the FET channel region having a substantially circular cross-sectional shape.
[0043] According to another aspect, the invention is directed to a method of fabricating a field effect transistor (FET). According to the method, source and drain regions are fainted on a semiconductor substrate. A plurality of preliminary channel regions are formed coupled between the source and drain regions. The preliminary channel regions are etched, and the etched preliminary channel regions are annealed to form FET channel regions, the FET channel regions having a substantially circular cross-sectional shape.
[0044] According to another aspect, the invention is directed to a field effect transistor (FET) having a semiconductor substrate and source and drain regions on the semiconductor substrate. A plurality of FET channel regions are coupled between the source and drain regions, the FET channel regions having a substantially circular cross-sectional shape, the FET channel regions being trimmed to a desired dimension such that a front surface of at least one of the FET channel regions is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions.
[0045] In one embodiment, the FET further comprises a gate dielectric layer on the FET channel regions.
[0046] In one embodiment, the FET further comprises a gate surrounding the FET channel regions.
[0047] In one embodiment, the FET further comprises the gate comprises polysilicon. In one embodiment, the FET further comprises the gate comprises metal.
[0048] According to another aspect, the invention is directed to a field effect transistor (FET) comprising a semiconductor substrate and source and drain regions on the semiconductor substrate. A FET channel region is coupled between the source and drain regions, the FET channel region having a substantially circular cross-sectional shape, the FET channel region being trimmed to a desired dimension such that a front surface of the FET channel region is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions.
[0049] According to the invention, a round-shaped (circular) nano-wire channel is produced in a FET using an etching process and an annealing process using H 2 . This process of manufacturing the FET reduces an electric field concentration phenomenon that occurs at the corner of a conventional FET having a square-shaped nano-wire channel. In producing the round-shaped nano-wire channel, the H2 annealing is done at relatively low temperature. Annealing at high temperature results in a nano-wire whose shape can result in the FET channel being cut or interrupted due to a silicon migration effect. Also, an uppermost silicon germanium layer used as a sacrificial layer can have a higher percentage of germanium than the other layers. This results in preventing the uppermost silicon channel layer from being consumed during etching. A damascene process can be used to form a self-aligned transistor gate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] The foregoing and other features and advantages of the invention will be apparent from the more particular description of preferred aspects of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the drawings, the thickness of layers and regions are exaggerated for clarity.
[0051] FIG. 1 is a schematic top plan view of a FET with a round or circular shaped nano-wire channel in accordance with an embodiment of the invention.
[0052] FIG. 2A is a schematic cross-sectional view of one embodiment of the FET of FIG. 1 , taken along line A-A′ of FIG. 1 .
[0053] FIG. 2B is a schematic cross-sectional view of the embodiment of the FET of FIG. 2A taken along line B-B′ of FIG. 1 .
[0054] FIG. 3 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 .
[0055] FIG. 4A is a schematic cross-sectional view of another embodiment of the FET in accordance with the invention corresponding to the line A-A′ of FIG. 1 .
[0056] FIG. 4B is a schematic cross-sectional view of the embodiment of the FET of FIG. 4A corresponding to the line B-B′ of FIG. 1 .
[0057] FIG. 5 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 .
[0058] FIG. 6A is a schematic cross-sectional view of another embodiment of a FET in accordance with the invention corresponding to the line A-A′ of FIG. 1 .
[0059] FIG. 6B is a schematic cross-sectional view of the FET of FIG. 6A corresponding to the line B-B′ of FIG. 1 .
[0060] FIG. 7 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 .
[0061] FIG. 8 is a logical flow diagram illustrating the process of forming the round-shaped nano-wire channels and gate of the FET according to the invention.
[0062] FIGS. 9A through 9D are schematic perspective views illustrating the steps in the process of forming the nano-wire channels and gate of the invention.
[0063] FIG. 10 is a detailed flow diagram illustrating the process of forming a round nano-wire channel from a square nano-wire channel, according to an embodiment of the invention.
[0064] FIGS. 11A through 11M are schematic perspective views illustrating steps in a process of manufacturing the FET of the invention, in accordance with an embodiment of the invention.
[0065] FIGS. 12A through 12K are views illustrating steps in a process of manufacturing the FET of the invention, in accordance with another embodiment of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0066] In the following detailed description, when a layer is described as being formed on another layer or on a substrate, the layer may be formed on the other layer or on the substrate, or a third layer may be interposed between the layer and the other layer or the substrate.
[0067] FIG. 1 is a schematic top plan view of a FET with a round or circular shaped nano-wire channel in accordance with an embodiment of the invention. FIG. 2A is a schematic cross-sectional view of one embodiment of the FET of FIG. 1 , taken along line A-A′ of FIG. 1 . FIG. 2B is a schematic cross-sectional view of the embodiment of the FET of FIG. 2A taken along line B-B′ of FIG. 1 .
[0068] Referring to FIGS. 1 , 2 A and 2 B, the FET structure of the invention includes a semiconductor substrate 110 . Source/drain regions 14 are formed on the substrate 110 . the source/drain regions 14 include a stacked structure of a first silicon germanium (SiGe) layer 14 a , a silicon layer 14 b and a second SiGe layer 14 c sequentially stacked as shown. The first and second SiGe layers and the silicon layers can be epitaxial layers. The silicon layer 14 b includes a round-shaped nano-wire channel region 12 extending across the structure along a longitudinal line X between the source/drain regions 14 . A portion of the substrate 110 protrudes above the surface of the substrate in the region beneath the nano-wire channel region 12 . As noted in FIG. 2B , the nano-wire channel 12 and the protruding portion of the substrate 110 are separated by a distance d. An isolation region 116 isolates the FET from other devices. A gate dielectric layer 30 made of a material such as silicon oxide surrounds the nano-wire channel region 12 . The gate dielectric layer 30 also surrounds the protruding portion of the substrate. A gate 20 made of a conductive material such as polysilicon, metal or a combination of polysilicon and metal surrounds the nano-wire channel region 12 . The gate 20 is insulated from the nano-wire channel 12 by the gate dielectric layer 30 .
[0069] FIG. 3 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 . The device 100 B of FIG. 3 differs from that of FIGS. 2A and 2B in that, instead of the multiple-layer stack having the first and second SiGe layers 14 a and 14 c and the Si layer 14 b , the device of FIG. 3 has only a single Si layer 14 d , which serves as the source/drain regions of the device and provides the round-shaped nano-wire channel 12 of the device.
[0070] FIG. 4A is a schematic cross-sectional view of another embodiment of the FET in accordance with the invention corresponding to the line A-A′ of FIG. 1 . FIG. 4B is a schematic cross-sectional view of the embodiment of the FET of FIG. 4A corresponding to the line B-B′ of FIG. 1 .
[0071] Referring to FIGS. 4A and 4B , the structure is different from that of the forgoing embodiments in that the FET 100 C includes multiple, i.e., two, round-shaped nano-wire channels 112 a and 112 b , instead of a single nano-wire channel 12 . The structure 100 C includes a semiconductor substrate 110 . Source/drain regions 114 are formed on the substrate 110 . The source/drain regions 114 are formed of a stacked structure of a first SiGe layer 114 a , a first Si layer 114 b , a second SiGe layer 114 c , a second Si layer 114 d and a third SiGe layer 114 e sequentially stacked as shown. The first, second and third SiGe layers 114 a , 114 c and 114 e and the first and second Si layers 114 b and 114 d can be epitaxial layers. The first Si layer 114 b includes a first round-shaped nano-wire channel region 112 a extending along a longitudinal line X 1 across the structure between the source/drain regions 114 . The second Si layer 114 d includes a second round-shaped nano-wire channel 112 b extending along a longitudinal line X 2 across the structure between the source/drain regions 114 . A portion of the substrate 110 protrudes above the surface of the substrate in the region beneath the nano-wire channel regions 112 a and 112 b . As noted in FIG. 4B , the first nano-wire channel 112 a and the protruding portion of the substrate 110 are separated by a distance d 1 . Also, the second nano-wire channel region 112 b and the protruding portion of the substrate 110 are separated by a distance d 2 . An isolation region 116 isolates the FET 100 C from other devices. A gate dielectric layer 30 made of a material such as silicon oxide surrounds the first and second nano-wire channel regions 112 a and 112 b . The gate dielectric layer 30 also surrounds the protruding portion of the substrate. A gate 20 made of a conductive material such as polysilicon, metal or a combination of polysilicon and metal surrounds the nano-wire channel regions 112 a and 112 b . The gate 20 is insulated from the nano-wire channels 112 a and 112 b by the gate dielectric layer 30 .
[0072] FIG. 5 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 . The device 100 D of FIG. 5 differs from that of FIGS. 4 a and 4 b in that, instead of the multiple-layer stack having the first, second and third SiGe layers 114 a , 114 c and 114 e and the first and second Si layers 114 b and 114 d , the device of FIG. 5 has only a single Si layer 114 f , which serves as the source/drain regions of the device and provides the round-shaped nano-wire channels 112 a and 112 b of the device.
[0073] FIG. 6A is a schematic cross-sectional view of another embodiment of a FET in accordance with the invention corresponding to the line A-A′ of FIG. 1 . FIG. 6B is a schematic cross-sectional view of the FET of FIG. 6A corresponding to the line B-B′ of FIG. 1 .
[0074] Referring to FIGS. 6A and 6B , the structure is different from that of the forgoing embodiments in that the FET 100 E includes multiple, i.e., three, round-shaped nano-wire channels 212 a , 212 b and 212 c , instead of the single nano-wire channel 12 or the two nano-wire channels 112 a and 112 b . The structure 100 E includes a semiconductor substrate 110 . Source/drain regions 214 are formed on the substrate 110 . The source/drain regions 214 are formed of a stacked structure of a first SiGe layer 214 a , a first Si layer 214 b , a second SiGe layer 214 c , a second Si layer 214 d , a third SiGe layer 214 e , a third Si layer 214 f and a fourth SiGe layer 214 g sequentially stacked as shown. The first, second, third and fourth SiGe layers 214 a , 214 c , 214 e and 214 g and the first, second and third Si layers 214 b , 214 d and 214 f can be epitaxial layers. The first Si layer 214 b includes a first round-shaped nano-wire channel region 212 a extending along a longitudinal line X 3 across the structure between the source/drain regions 214 . The second Si layer 214 d includes a second round-shaped nano-wire channel 212 b extending along a longitudinal line X 4 across the structure between the source/drain regions 214 . The third Si layer 214 f includes a third round-shaped nano-wire channel 212 c extending along a longitudinal line X 5 across the structure between the source/drain regions 214 . A portion of the substrate 110 protrudes above the surface of the substrate in the region beneath the nano-wire channel regions 212 a , 212 b and 212 c . As noted in FIG. 6B , the first nano-wire channel 212 a and the protruding portion of the substrate 110 are separated by a distance d 1 . Also, the second nano-wire channel region 212 b and the protruding portion of the substrate 110 are separated by a distance d 2 . Also, the third nano-wire channel 212 c and the protruding portion of the substrate 110 are separated by a distance d 3 . An isolation region 116 isolates the FET 100 E from other devices. A gate dielectric layer 30 made of a material such as silicon oxide surrounds the first, second and third nano-wire channel regions 212 a , 212 b and 212 c . The gate dielectric layer 30 also surrounds the protruding portion of the substrate. A gate 20 made of a conductive material such as polysilicon, metal or a combination of polysilicon and metal surrounds the nano-wire channel regions 212 a , 212 b and 212 c . The gate 20 is insulated from the nano-wire channels 212 a , 212 b and 212 c by the gate dielectric layer 30 .
[0075] FIG. 7 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 . The device 100 F of FIG. 7 differs from that of FIGS. 6A and 6B in that, instead of the multiple-layer stack having the first, second, third and fourth SiGe layers 214 a , 214 c , 214 e and 214 g and the first, second and third Si layers 214 b , 214 d and 214 f , the device of FIG. 7 has only a single Si layer 214 h , which serves as the source/drain regions of the device and provides the round-shaped nano-wire channels 212 a , 212 b and 212 c of the device.
[0076] FIG. 8 is a logical flow diagram illustrating the process of forming the round-shaped nano-wire channels and gate of the FET according to the invention. FIGS. 9A through 9D are schematic perspective views illustrating the steps in the process of forming the nano-wire channels and gate of the invention. The process of forming the nano-wire channels, the gate and the FET of the invention described herein is applicable to any of the embodiments of the FET described herein. Specifically, the formation process is applicable to a FET having any number of round-shaped nano-wire channels.
[0077] Referring to FIGS. 8 and 9A through 9 D, in step S 50 , an active Si pattern having a polygonal cross-sectional shape is formed. For example, referring specifically to FIG. 9A , the active Si pattern 402 can have flat exterior surfaces 402 b and a substantially square shape 402 a in cross section.
[0078] Next, in step S 60 , a cleaning process is performed to remove any oxide that may have formed on the active Si pattern 402 .
[0079] Next, in step S 70 , etching is performed to remove square corners from the active pattern 402 . An annealing step is performed to complete the round-shaped Si nano-wire channel 404 . As shown in FIG. 9B , the channel 404 has a substantially round shape 404 a in cross section.
[0080] Next, in step S 80 , a gate dielectric layer 406 is formed surrounding the round-shaped nano-wire channel region 404 , as shown in FIG. 9C .
[0081] Next, in step S 90 , a gate electrode 408 is formed surrounding the gate dielectric layer 406 and the round-shaped or cylindrical Si nano-wire channel 404 , as shown in FIG. 9D . The gate electrode 408 is made of a conductive material such as polysilicon, metal, or a combination of polysilicon and metal.
[0082] FIG. 10 is a detailed flow diagram illustrating the process of forming the round nano-wire channel 404 from the square nano-wire channel 402 . FIG. 10 will be described below in detail.
[0083] FIGS. 11A through 11M are schematic perspective views illustrating steps in a process of manufacturing the FET of the invention, in accordance with an embodiment of the invention. Referring to FIG. 11A , a silicon substrate 500 is provided. A first silicon germanium (SiGe) layer 512 is formed on top of the substrate 500 . The first SiGe layer 512 can have a thickness of 5-50 nm and can contain 15-20% germanium. An active silicon layer 514 is formed over the first SiGe layer. The silicon layer 514 is the layer of which the round-shaped nano-wire channel region of the FET will eventually be formed. A second SiGe layer 516 is formed on the silicon layer 514 . The second SiGe layer 516 can be formed to a thickness of 5-50 nm and can contain 5-10% germanium. The second SiGe layer 516 may have a lower concentration of germanium such that during a subsequent etching process, the rate at which the upper layer of SiGe is consumed is lower to prevent damage to the silicon layer 514 to ensure a good nano-wire channel. In one embodiment, the first and second SiGe layers 512 and 516 and the silicon layer 514 are grown epitaxially to the thickness of 5-50 nm.
[0084] A capping layer 518 is then formed over the second SiGe layer 516 . The capping layer may be a buffer oxide layer made of a material having a high etch selectivity with respect to silicon nitride (SiN), such as silicon oxide, for a subsequent etching process. Next, a hard mask layer, made of a material such as SiN, is formed on the buffer oxide layer 518 . The hard mask layer is patterned such as by photolithographic and etching processes to form a hard mask pattern 520 on the buffer oxide layer 518 .
[0085] Referring to FIG. 11B , the structure is etched using the hard mask pattern 520 as an etching mask to form a STI trench 522 . In one embodiment, the trench depth is 150-350 nm.
[0086] Referring to FIG. 11C , next, a shallow trench isolation (STI) 524 is formed in the trench 522 . The STI is formed by a high density plasma (HDP) process to deposit an oxide. After the HDP process, a chemical mechanical polishing (CMP) process is carried out to expose the top surface of the hard mask pattern 520 . As shown in the drawing, the slurry used during the CMP process has a higher polishing rate on the HDP oxide 524 than it has on the hard mask pattern 520 such that a step is created between the HDP oxide 524 and the hard mask pattern 520 .
[0087] Next, referring to FIG. 11D , the hard mask pattern 520 and a portion of the HDP oxide is removed using phosphoric acid, leaving the buffer oxide layer 518 and the top surface of the HDP oxide 524 exposed on the top of the structure.
[0088] Next, referring to FIG. 11E , a second hard mask pattern 530 is formed on the top surface of the structure by forming a hard mask layer made of SiN and then applying photolithographic and etching processes to pattern the hard mask layer.
[0089] Next, referring to FIG. 11F , the structure is etched using the second hard mask pattern 530 as an etching mask to form a STI recess 532 . The depth of the recess 532 is controlled to be deeper than the total thickness of the first and second SiGe layers 512 , 516 and the Si layer 514 . That is, the recess 532 extends down into the structure deeper than the bottom of the epitaxial SiGe and Si layers. The width of the remaining epitaxial SiGe and Si layers, as well as a portion of the substrate beneath the epitaxial layers is indicated in the figure as W 1 .
[0090] Next, referring to FIG. 11G , the remaining portion of the SiGe epitaxial layers 512 and 516 , the remaining portion of the active Si layer 514 a and the raised portion of the substrate beneath the epitaxial layers having the width W 1 are optionally trimmed by etching, such that the remaining portion of the epitaxial layers and the raised portion of the substrate beneath the epitaxial layers has a width W 2 . The etching is preferably a chemical dry etch (CDE), which can be carried out, for example, at 400 W, 225 mTorr, 250 degrees C. for 20 seconds, in an atmosphere containing CF 4 and O 2 at flow rates of 60 and 150 seem, respectively. The width W 2 is selected based on a desired size of the final nano-wire channel to be formed. The CDE is performed to reduce the channel width to W 2 and to make the channel square in cross-section. FIG. 11H is the structure of FIG. 11G rotated 90 degrees to clearly illustrate the resulting structure.
[0091] Next, referring to FIG. 11I , the sacrificial SiGe layers 512 and 516 on the top and bottom of the channel region 514 a are removed to completely expose the channel region 514 a . It is also noted that a rectangular portion of the substrate 500 also remains beneath the channel region 514 a following this step. This step is performed by a chemical wet etch using a chemical including CH 3 COOOH (or CH 3 COOH)+HF+DIW (deionized water) (+H2O2+surfactant, etc.).
[0092] Next, referring to FIG. 11J , the square cross-sectional channel region 514 a is formed into a nano-wire channel 514 b having a round or circular cross-section. This is performed by etching and annealing the square cross-sectional channel region 514 a until it becomes the round nano-wire channel 514 b.
[0093] FIG. 12 is a flow diagram illustrating the process of forming the round nano-wire channel 514 b from the square nano-wire channel 514 a . First, an optional cleaning step S 100 is performed in an atmosphere of H2. In one embodiment, the cleaning is performed in an atmosphere of 100% H2. Alternatively, the atmosphere can also contain Ar and/or He with or without the H2. In one embodiment, the cleaning is performed at a pressure of 0.1 to 10 Torr and a temperature of 600-900 degrees C. In one particular embodiment, the cleaning is performed at a temperature of 700-800 degrees C. The gas flow rate during the cleaning step can be 1-500 sccm, and the process time can be 1-5 minutes.
[0094] After the cleaning step, the four corners of the square nano-wire channel 514 a are etched in step 5200 . The etching is carried out by introducing a combination of HCl and H2 gas into the process chamber. In one particular embodiment, the gas flow rate of HCl during the etching is 100-2000 sccm, and the gas flow rate of the H2 is 100-2000 sccm. The flow rate ratio of HCl:H2 can be in a range of 5:5 to 3:7. In one particular embodiment, the flow rate ratio of HCl:H2 is 300 sccm: 500 sccm. The etch temperature can be in the range of 600-900 degrees C., and the pressure can be 10-100 Torr. The time of the etch can be in the range of 1-120 seconds.
[0095] The etch of step 5200 can be performed under one of at least three possible sets of conditions. For a relatively long-duration, low-temperature etch, the etch temperature can be in the range of 600-700 degrees C. For a relatively short-duration, high-temperature etch, the etch temperature can be in the range of 850-900 degrees C. Between the two process conditions above, the middle-duration, middle-temperature etch can be carried out at a temperature between 750 and 820 degrees C.
[0096] After the etching process, a low-temperature annealing is carried out in step S 300 to form the round-shaped nano-wire channel region 514 b . The annealing is performed in an atmosphere of H2 gas. In one embodiment, the annealing is performed at a pressure of 0.1-10 Torr. If the pressure is lowered, the process time can also be lowered. In one embodiment, the annealing is performed at a temperature of 600-900 degrees C. for a period of 10-800 seconds. In one embodiment, the H 2 gas flow rate is 1-500 sccm. In one particular embodiment, the annealing is carried out at a temperature of about 810 degrees C., at a pressure of 5 Torr and for a period of 500 seconds.
[0097] The etching and annealing steps can be repeated as many times as are needed to form the final round-shaped nano-wire channel 514 b . Between the annealing step S 300 and the next repeated etching step S 200 , a purging step S 400 can be performed to remove the remaining annealing H 2 gas from the process chamber. The purge can be performed using at least one of Ar, He and H 2 gas.
[0098] After the purging step S 400 , a determination is made in step S 500 as to whether the channel 514 b is the desired size and/or shape. If the channel 514 b is of the proper shape and size, the process ends. If not, the process returns to step S 200 to begin another cycle of etching, annealing (S 300 ) and optional purging (S 400 ).
[0099] Referring to FIG. 11K , after the round-shaped nano-wire channel 514 b is formed, a gate dielectric layer is formed on the structure, including surrounding the nano-wire channel 514 b . The gate dielectric can be formed by growing SiO2 on the structure using O2 gas. Next, a gate material such as polysilicon or a metal layer with polysilicon is formed surrounding the nano-wire channel 514 b . Then the gate material is planarized such as by chemical mechanical polishing (CMP) to form the gate 540 surrounding the nano-wire channel 514 b.
[0100] Next, referring to FIG. 11L , the second hard mask pattern 530 is removed. FIG. 11M illustrates the final structure with the gate pattern 540 shown in phantom. FIG. 11M shows the round-shaped nano-wire channel 514 b and the raised portion of the substrate 500 , which have both been formed into a round shape by the etching and annealing steps of the invention.
[0101] It is noted that this embodiment of manufacturing a FET is applicable to formation of any number of channel regions. Where more channel regions are to be formed, more alternating layers of SiGe and Si are initially formed.
[0102] It should be noted that FIG. 2A corresponds to a cross-sectional view of FIG. 11L , taken along line IIa-IIa′ of FIG. 11L . Likewise, FIG. 2B corresponds to a cross-sectional view of FIG. 11L , taken along line IIb-IIb′ of FIG. 11L .
[0103] FIGS. 12A through 12K are views illustrating steps in a process of manufacturing the FET of the invention, in accordance with another embodiment of the invention. The initial steps used in the embodiment of FIGS. 12A through 12K are the same as those illustrated in the previously described embodiment for steps 11 A through 11 D. For the remaining steps, where a step is analogous to a step described in connection with the embodiment of FIGS. 11A through 11M , the step is carried out in similar fashion. Therefore, description of those steps will not be repeated. FIG. 12A-12F are schematic cross-sectional views of the structure of FIG. 11D , taken along line XII-XII′ of FIG. 11D , illustrating steps in the process of manufacturing a FET according to the embodiment of the invention. FIGS. 12G-12K are schematic perspective views illustrating steps in the process of manufacturing a FET according to the embodiment of the invention. Referring to FIG. 12A , the structure resulting after performance of steps 11 A through 11 D is illustrated.
[0104] Next, referring to FIG. 12B , a hard mask pattern 630 is formed on the structure. The hard mask pattern 630 can be formed by patterning a layer of SiN.
[0105] Next, referring to FIG. 12C , recessed regions 632 are formed in the structure. This can be performed by etching a trench to a depth deeper than the first epitaxial SiGe layer 512 using the hard mask pattern 630 as an etching mask.
[0106] Next, referring to FIG. 12D , the recess 632 is partially filled by epitaxially growing a Si layer 640 in the recess. In one embodiment, the epitaxial Si layer 640 is grown to a depth higher than the second epitaxial SiGe layer 516 .
[0107] Next, referring to FIG. 12E , another hard mask pattern made of, for example, SiN is formed above the epitaxial Si layer 640 and adjacent to the hard mask pattern 630 .
[0108] Referring to FIGS. 12F and 12G , the hard mask pattern 630 is then removed, exposing the top or second epitaxial SiGe layer 516 and a portion of the top surface of the STI dielectric layer 524 .
[0109] Next, referring to FIG. 12H , the structure is etched to remove a portion of the STI dielectric layer 524 to form a damascene recessed region 532 to expose the sides of the stack of the first and second SiGe layers 512 and 516 , the Si layer 514 and a portion of the substrate 500 beneath the stacked epitaxial layers 512 , 514 and 516 .
[0110] Next, referring to FIG. 12I , the structure is etched, preferably by a chemical dry etch to trim the first and second sacrificial SiGe layers 512 and 516 , the Si layer 514 and the protruding portion of the substrate 500 . The trimming also exposes a portion of the epitaxial Si layer 640 as shown.
[0111] Next, referring to FIG. 12J , the sacrificial SiGe layers 512 and 516 on the top and bottom of the channel region 514 a are removed to completely expose the channel region 514 a . It is also noted that the rectangular protruding portion of the substrate 500 also remains beneath the channel region 514 a following this step. This step is performed by a chemical wet etch using a chemical including CH 3 COOOH (or CH 3 COOH)+HF+DIW (deionized water) (+H2O2+surfactant, etc.).
[0112] Next, referring to FIG. 12K , the channel region 514 a is cleaned, etched and annealed in accordance with the description of FIG. 10 to form the round-shaped nano-wire channel region 514 b . It is noted that in this embodiment, the source/drain regions of the FET are made from the single epitaxial Si layer 640 , as opposed to the stacked structure of epitaxial SiGe and Si layers. It is also noted that this embodiment, like the previously described embodiment, is applicable to formation of any number of channel regions. Where more channel regions are to be formed, more alternating layers of SiGe and Si are initially formed.
[0113] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. | A field-effect transistor (FET) with a round-shaped nano-wire channel and a method of manufacturing the FET are provided. According to the method, source and drain regions are formed on a semiconductor substrate. A plurality of preliminary channel regions is coupled between the source and drain regions. The preliminary channel regions are etched, and the etched preliminary channel regions are annealed to form FET channel regions, the FET channel regions having a substantially circular cross-sectional shape. | Briefly describe the main invention outlined in the provided context. | [
"RELATED APPLICATION [0001] This application is a divisional application of the U.S. patent application Ser.",
"No. 11/303,408, filed on Dec. 16, 2005, which claims the benefit of Korean patent application number 10-2005-0024543, filed on Mar. 24, 2005, in the Korean Intellectual Property Office, the contents of which applications are incorporated herein in their entirety by reference.",
"FIELD OF THE INVENTION [0002] The invention relates to field-effect transistors (FETs) on semiconductor substrates and manufacturing methods thereof, and, more particularly, to a FET having a round-shaped, i.e., circular, nano-wire channel and a fabricating method thereof.",
"DESCRIPTION OF THE RELATED ART [0003] As applications for semiconductor devices expand, highly-integrated and/or high-speed semiconductor devices are increasingly in demand.",
"As integration density of semiconductor devices increases, a design rule becomes smaller.",
"As a result of the decreasing design rule, a channel length and a channel width of a field effect transistor (FET) similarly decrease.",
"A decrease in channel length may result in a short channel effect.",
"A decrease in channel width may result in a narrow channel effect.",
"The short channel effect may significantly influence potential in a source/drain region upon a channel region.",
"The narrow channel width effect may generally increase a threshold voltage.",
"However, in the case of a device using a STI (Shallow Trench Isolation), a channel width that is too narrow may decrease a threshold voltage.",
"This is referred to as an inverse narrow width effect.",
"In an attempt to prevent generation of the short channel effect and/or the narrow channel effect, various FETs having new structures have been proposed.",
"[0004] Recently, efforts have been made, particularly in the area of nano-size technology in the semiconductor field, to increase drive current of a transistor and decrease the short channel effect.",
"Conventionally, several methods have been used in an effort to achieve these results.",
"Examples of these attempts include a recessed channel array transistor (RCAT), a fin-type FET (FinFET), and gate-all-around transistor (GAT) technologies.",
"[0005] Each of these conventional devices and the corresponding methods of fabricating these devices, suffer from one of more disadvantages.",
"For example, these conventional devices are limited in an ability to perform fast operations.",
"Moreover, the number of spaced channel layers in these conventional devices is limited due to fabrication limitations, e.g., with respect to an etching depth that can be achieved during dry etching.",
"SUMMARY OF THE INVENTION [0006] The present invention is therefore directed to a FET having one or more nano-wire channels and a method of manufacturing the FET, which substantially overcome one or more of the drawbacks due to the limitations and disadvantages of the prior art.",
"[0007] According to a first aspect, the invention is directed to a method of fabricating a field effect transistor (FET).",
"According to the method, source and drain regions are formed on a semiconductor substrate.",
"A plurality of preliminary channel regions are formed coupled between the source and drain regions.",
"The preliminary channel regions are etched, and the etched preliminary channel regions are annealed to form FET channel regions, the FET channel regions having a substantially circular cross-sectional shape.",
"[0008] In one embodiment, the preliminary channel regions have a substantially rectangular cross-sectional shape.",
"In one embodiment, the preliminary channel regions have corners in cross-section.",
"[0009] In one embodiment, the etching is performed in an atmosphere containing one or both of HCl and H 2 .",
"In one embodiment, a ratio of a flow rate of HCl to a flow rate of H 2 is from 3:7 to 1:1.",
"In one particular embodiment, the ratio of flow rate of HCl to flow rate of H 2 is 3:5.",
"[0010] In one embodiment, the etching is performed at a temperature of 600 to 900 degrees C. The etching can be performed for a period of 1 to 120 seconds.",
"The etching can be performed at a pressure of 10 to 100 Torr.",
"[0011] In one embodiment, the annealing is performed in an atmosphere containing H 2 .",
"The annealing can be performed with H 2 introduced at a flow rate of 1 to 500 seem.",
"The annealing can be performed at a temperature of 600 to 900 degrees C., and, more particularly, at a temperature of 810 degrees C. The annealing can be performed for a period of 10 to 800 seconds, and, more particularly, for a period of 500 seconds.",
"[0012] In one embodiment, the method further comprises, after forming the preliminary channel regions, cleaning the structure to remove oxide from the structure.",
"The cleaning can be performed in an atmosphere containing at least one of H 2 , Ar and He.",
"The cleaning can be performed at a temperature of 600 to 900 degrees C. The cleaning can be performed at a gas flow rate of 1 to 500 sccm.",
"The cleaning can be performed for a period of 1 to 5 minutes.",
"The cleaning can be performed at a pressure of 0.1 to 10 Torr.",
"In one embodiment, forming the plurality of preliminary channel regions comprises forming a channel layer and a sacrificial layer vertically adjacent to the channel layer.",
"In one embodiment, the channel layer and the sacrificial layer are formed epitaxially.",
"In one embodiment, the channel layer is a silicon layer.",
"In one embodiment, the sacrificial layer is a SiGe layer.",
"[0013] In one embodiment, forming the plurality of preliminary channel regions further comprises trimming the channel layer to a desired dimension such that a front surface of at least one of the preliminary channel regions is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions.",
"The trimming can included etching the channel layer.",
"Etching the channel layer can include a chemical dry etch.",
"[0014] In one embodiment, forming the plurality of preliminary channel regions further comprises forming a mask layer over the channel layer and sacrificial layer, the mask layer defining a region separating the FET channel regions.",
"[0015] In one embodiment, forming the plurality of preliminary channel regions comprises forming a plurality of sacrificial layers vertically adjacent to a channel layer.",
"The sacrificial layers can comprise SiGe.",
"An upper sacrificial layer can have a lower concentration of germanium than a lower sacrificial layer.",
"[0016] In one embodiment, the method further comprises purging a process chamber between etching the preliminary channel regions and annealing the etched preliminary channel regions.",
"[0017] In one embodiment, the etching and annealing steps are performed at least two times.",
"In one embodiment, the method further comprises purging steps between a prior etching step and a next annealing step.",
"[0018] In one embodiment, the method further comprises forming a gate dielectric layer on the FET channel regions.",
"[0019] In one embodiment, the method further comprises forming a gate surrounding the FET channel regions.",
"the gate can include polysilicon.",
"Also, the gate comprises metal.",
"[0020] According to another aspect, the invention is directed to a method of fabricating a field effect transistor (FET).",
"According to the method, at least one channel layer and at least one sacrificial layer are alternately stacked on a substrate.",
"Source and drain regions are formed on the substrate coupled to the alternately stacked at least one channel layer and at least one sacrificial layer.",
"The alternately stacked at least one channel layer and at least one sacrificial layer are patterned to form a plurality of preliminary channel regions coupled between the source and drain regions.",
"A remaining portion of the at least one sacrificial layer is removed.",
"The preliminary channel regions are etched, the etched preliminary channel regions are annealed to form FET channel regions, the FET channel regions having a substantially circular cross-sectional shape.",
"[0021] In one embodiment, the preliminary channel regions have a substantially rectangular cross-sectional shape.",
"In one embodiment, the preliminary channel regions have corners in cross-section.",
"[0022] In one embodiment, the at least one channel layer and the at least one sacrificial layer are formed epitaxially.",
"[0023] In one embodiment, the at least one channel layer is a silicon layer.",
"In one embodiment, the at least one sacrificial layer is a SiGe layer.",
"[0024] In one embodiment, forming the plurality of preliminary channel regions further comprises trimming the at least one channel layer to a desired dimension such that a front surface of at least one of the preliminary channel regions is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions.",
"In one embodiment, the trimming comprises etching the at least one channel layer.",
"Etching the at least one channel layer can include a chemical dry etch.",
"[0025] In one embodiment, forming the plurality of preliminary channel regions further comprises forming a mask layer over the at least one channel layer and at least one sacrificial layer, the mask layer defining a region separating the FET channel regions.",
"[0026] In one embodiment, forming the plurality of preliminary channel regions comprise forming a plurality of sacrificial layers vertically adjacent to the channel layer.",
"[0027] The sacrificial layers can comprise SiGe.",
"In one embodiment, an upper sacrificial layer has a lower concentration of germanium than a lower sacrificial layer.",
"[0028] In one embodiment, the method further comprises purging a process chamber between etching the preliminary channel regions and annealing the etched preliminary channel regions.",
"[0029] In one embodiment, the method further comprises forming a gate dielectric layer on the FET channel regions.",
"[0030] In one embodiment, the method further comprises forming a gate surrounding the FET channel regions.",
"The gate can include polysilicon.",
"Also, the gate can include metal.",
"[0031] According to another aspect, the invention is directed to a method of fabricating a field effect transistor (FET).",
"According to the method, source and drain regions are formed on a semiconductor substrate.",
"A plurality of preliminary channel regions are formed coupled between the source and drain regions.",
"Forming the plurality of preliminary channel regions comprises: (i) forming a channel layer and a sacrificial layer vertically adjacent to the channel layer, and (ii) trimming the channel layer to a desired dimension such that a front surface of at least one of the preliminary channel regions is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions.",
"The preliminary channel regions are etched, and the etched preliminary channel regions are annealed to form FET channel regions, the FET channel regions having a substantially circular cross-sectional shape.",
"[0032] In one embodiment, the preliminary channel regions have a substantially rectangular cross-sectional shape.",
"In one embodiment, the preliminary channel regions have corners in cross-section.",
"[0033] In one embodiment, the method further comprises, after forming the preliminary channel regions, cleaning the structure to remove oxide from the structure.",
"[0034] In one embodiment, the channel layer and the sacrificial layer are formed epitaxially.",
"[0035] The channel layer can be a silicon layer, and the sacrificial layer can be a SiGe layer.",
"[0036] In one embodiment, the trimming comprises etching the channel layer.",
"Etching the channel layer can include a chemical dry etch.",
"[0037] In one embodiment, forming the plurality of preliminary channel regions comprises forming a plurality of sacrificial layers vertically adjacent to the channel layer.",
"The sacrificial layers can include SiGe.",
"An upper sacrificial layer can have a lower concentration of germanium than a lower sacrificial layer.",
"[0038] In one embodiment, the method further comprises purging a process chamber between etching the preliminary channel regions and annealing the etched preliminary channel regions.",
"[0039] In one embodiment, the method further comprises forming a gate dielectric layer on the FET channel regions.",
"[0040] In one embodiment, the method further comprises forming a gate surrounding the FET channel regions.",
"In one embodiment, the gate comprises polysilicon.",
"In one embodiment, the gate comprises metal.",
"[0041] According to another aspect, the invention is directed to a method of fabricating a field effect transistor (FET).",
"According to the method, source and drain regions are formed on a semiconductor substrate.",
"A preliminary channel region is formed coupled between the source and drain regions, forming the preliminary channel region comprising: (i) forming a channel layer and a sacrificial layer vertically adjacent to the channel layer, and (ii) trimming the channel layer to a desired dimension such that a front surface of the preliminary channel region is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions.",
"A remaining portion of the sacrificial layer is removed.",
"The trimmed channel layer is etched, and the etched channel layer is annealed to form a FET channel region, the FET channel region having a substantially circular cross-sectional shape.",
"[0042] According to another aspect, the invention is directed to a method of fabricating a field effect transistor (FET).",
"According to the method, source and drain regions are formed on a semiconductor substrate.",
"A preliminary channel region is formed coupled between the source and drain regions, forming the preliminary channel region comprising forming a channel layer and a sacrificial layer vertically adjacent to the channel layer.",
"A remaining portion of the sacrificial layer is removed.",
"The preliminary channel region is etched, and the etched preliminary channel region is annealed to form a FET channel region, the FET channel region having a substantially circular cross-sectional shape.",
"[0043] According to another aspect, the invention is directed to a method of fabricating a field effect transistor (FET).",
"According to the method, source and drain regions are fainted on a semiconductor substrate.",
"A plurality of preliminary channel regions are formed coupled between the source and drain regions.",
"The preliminary channel regions are etched, and the etched preliminary channel regions are annealed to form FET channel regions, the FET channel regions having a substantially circular cross-sectional shape.",
"[0044] According to another aspect, the invention is directed to a field effect transistor (FET) having a semiconductor substrate and source and drain regions on the semiconductor substrate.",
"A plurality of FET channel regions are coupled between the source and drain regions, the FET channel regions having a substantially circular cross-sectional shape, the FET channel regions being trimmed to a desired dimension such that a front surface of at least one of the FET channel regions is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions.",
"[0045] In one embodiment, the FET further comprises a gate dielectric layer on the FET channel regions.",
"[0046] In one embodiment, the FET further comprises a gate surrounding the FET channel regions.",
"[0047] In one embodiment, the FET further comprises the gate comprises polysilicon.",
"In one embodiment, the FET further comprises the gate comprises metal.",
"[0048] According to another aspect, the invention is directed to a field effect transistor (FET) comprising a semiconductor substrate and source and drain regions on the semiconductor substrate.",
"A FET channel region is coupled between the source and drain regions, the FET channel region having a substantially circular cross-sectional shape, the FET channel region being trimmed to a desired dimension such that a front surface of the FET channel region is offset with respect to a front surface of the source and drain regions in a direction normal to the front surface of the source and drain regions.",
"[0049] According to the invention, a round-shaped (circular) nano-wire channel is produced in a FET using an etching process and an annealing process using H 2 .",
"This process of manufacturing the FET reduces an electric field concentration phenomenon that occurs at the corner of a conventional FET having a square-shaped nano-wire channel.",
"In producing the round-shaped nano-wire channel, the H2 annealing is done at relatively low temperature.",
"Annealing at high temperature results in a nano-wire whose shape can result in the FET channel being cut or interrupted due to a silicon migration effect.",
"Also, an uppermost silicon germanium layer used as a sacrificial layer can have a higher percentage of germanium than the other layers.",
"This results in preventing the uppermost silicon channel layer from being consumed during etching.",
"A damascene process can be used to form a self-aligned transistor gate.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0050] The foregoing and other features and advantages of the invention will be apparent from the more particular description of preferred aspects of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views.",
"The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.",
"In the drawings, the thickness of layers and regions are exaggerated for clarity.",
"[0051] FIG. 1 is a schematic top plan view of a FET with a round or circular shaped nano-wire channel in accordance with an embodiment of the invention.",
"[0052] FIG. 2A is a schematic cross-sectional view of one embodiment of the FET of FIG. 1 , taken along line A-A′ of FIG. 1 .",
"[0053] FIG. 2B is a schematic cross-sectional view of the embodiment of the FET of FIG. 2A taken along line B-B′ of FIG. 1 .",
"[0054] FIG. 3 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 .",
"[0055] FIG. 4A is a schematic cross-sectional view of another embodiment of the FET in accordance with the invention corresponding to the line A-A′ of FIG. 1 .",
"[0056] FIG. 4B is a schematic cross-sectional view of the embodiment of the FET of FIG. 4A corresponding to the line B-B′ of FIG. 1 .",
"[0057] FIG. 5 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 .",
"[0058] FIG. 6A is a schematic cross-sectional view of another embodiment of a FET in accordance with the invention corresponding to the line A-A′ of FIG. 1 .",
"[0059] FIG. 6B is a schematic cross-sectional view of the FET of FIG. 6A corresponding to the line B-B′ of FIG. 1 .",
"[0060] FIG. 7 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 .",
"[0061] FIG. 8 is a logical flow diagram illustrating the process of forming the round-shaped nano-wire channels and gate of the FET according to the invention.",
"[0062] FIGS. 9A through 9D are schematic perspective views illustrating the steps in the process of forming the nano-wire channels and gate of the invention.",
"[0063] FIG. 10 is a detailed flow diagram illustrating the process of forming a round nano-wire channel from a square nano-wire channel, according to an embodiment of the invention.",
"[0064] FIGS. 11A through 11M are schematic perspective views illustrating steps in a process of manufacturing the FET of the invention, in accordance with an embodiment of the invention.",
"[0065] FIGS. 12A through 12K are views illustrating steps in a process of manufacturing the FET of the invention, in accordance with another embodiment of the invention.",
"DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0066] In the following detailed description, when a layer is described as being formed on another layer or on a substrate, the layer may be formed on the other layer or on the substrate, or a third layer may be interposed between the layer and the other layer or the substrate.",
"[0067] FIG. 1 is a schematic top plan view of a FET with a round or circular shaped nano-wire channel in accordance with an embodiment of the invention.",
"FIG. 2A is a schematic cross-sectional view of one embodiment of the FET of FIG. 1 , taken along line A-A′ of FIG. 1 .",
"FIG. 2B is a schematic cross-sectional view of the embodiment of the FET of FIG. 2A taken along line B-B′ of FIG. 1 .",
"[0068] Referring to FIGS. 1 , 2 A and 2 B, the FET structure of the invention includes a semiconductor substrate 110 .",
"Source/drain regions 14 are formed on the substrate 110 .",
"the source/drain regions 14 include a stacked structure of a first silicon germanium (SiGe) layer 14 a , a silicon layer 14 b and a second SiGe layer 14 c sequentially stacked as shown.",
"The first and second SiGe layers and the silicon layers can be epitaxial layers.",
"The silicon layer 14 b includes a round-shaped nano-wire channel region 12 extending across the structure along a longitudinal line X between the source/drain regions 14 .",
"A portion of the substrate 110 protrudes above the surface of the substrate in the region beneath the nano-wire channel region 12 .",
"As noted in FIG. 2B , the nano-wire channel 12 and the protruding portion of the substrate 110 are separated by a distance d. An isolation region 116 isolates the FET from other devices.",
"A gate dielectric layer 30 made of a material such as silicon oxide surrounds the nano-wire channel region 12 .",
"The gate dielectric layer 30 also surrounds the protruding portion of the substrate.",
"A gate 20 made of a conductive material such as polysilicon, metal or a combination of polysilicon and metal surrounds the nano-wire channel region 12 .",
"The gate 20 is insulated from the nano-wire channel 12 by the gate dielectric layer 30 .",
"[0069] FIG. 3 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 .",
"The device 100 B of FIG. 3 differs from that of FIGS. 2A and 2B in that, instead of the multiple-layer stack having the first and second SiGe layers 14 a and 14 c and the Si layer 14 b , the device of FIG. 3 has only a single Si layer 14 d , which serves as the source/drain regions of the device and provides the round-shaped nano-wire channel 12 of the device.",
"[0070] FIG. 4A is a schematic cross-sectional view of another embodiment of the FET in accordance with the invention corresponding to the line A-A′ of FIG. 1 .",
"FIG. 4B is a schematic cross-sectional view of the embodiment of the FET of FIG. 4A corresponding to the line B-B′ of FIG. 1 .",
"[0071] Referring to FIGS. 4A and 4B , the structure is different from that of the forgoing embodiments in that the FET 100 C includes multiple, i.e., two, round-shaped nano-wire channels 112 a and 112 b , instead of a single nano-wire channel 12 .",
"The structure 100 C includes a semiconductor substrate 110 .",
"Source/drain regions 114 are formed on the substrate 110 .",
"The source/drain regions 114 are formed of a stacked structure of a first SiGe layer 114 a , a first Si layer 114 b , a second SiGe layer 114 c , a second Si layer 114 d and a third SiGe layer 114 e sequentially stacked as shown.",
"The first, second and third SiGe layers 114 a , 114 c and 114 e and the first and second Si layers 114 b and 114 d can be epitaxial layers.",
"The first Si layer 114 b includes a first round-shaped nano-wire channel region 112 a extending along a longitudinal line X 1 across the structure between the source/drain regions 114 .",
"The second Si layer 114 d includes a second round-shaped nano-wire channel 112 b extending along a longitudinal line X 2 across the structure between the source/drain regions 114 .",
"A portion of the substrate 110 protrudes above the surface of the substrate in the region beneath the nano-wire channel regions 112 a and 112 b .",
"As noted in FIG. 4B , the first nano-wire channel 112 a and the protruding portion of the substrate 110 are separated by a distance d 1 .",
"Also, the second nano-wire channel region 112 b and the protruding portion of the substrate 110 are separated by a distance d 2 .",
"An isolation region 116 isolates the FET 100 C from other devices.",
"A gate dielectric layer 30 made of a material such as silicon oxide surrounds the first and second nano-wire channel regions 112 a and 112 b .",
"The gate dielectric layer 30 also surrounds the protruding portion of the substrate.",
"A gate 20 made of a conductive material such as polysilicon, metal or a combination of polysilicon and metal surrounds the nano-wire channel regions 112 a and 112 b .",
"The gate 20 is insulated from the nano-wire channels 112 a and 112 b by the gate dielectric layer 30 .",
"[0072] FIG. 5 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 .",
"The device 100 D of FIG. 5 differs from that of FIGS. 4 a and 4 b in that, instead of the multiple-layer stack having the first, second and third SiGe layers 114 a , 114 c and 114 e and the first and second Si layers 114 b and 114 d , the device of FIG. 5 has only a single Si layer 114 f , which serves as the source/drain regions of the device and provides the round-shaped nano-wire channels 112 a and 112 b of the device.",
"[0073] FIG. 6A is a schematic cross-sectional view of another embodiment of a FET in accordance with the invention corresponding to the line A-A′ of FIG. 1 .",
"FIG. 6B is a schematic cross-sectional view of the FET of FIG. 6A corresponding to the line B-B′ of FIG. 1 .",
"[0074] Referring to FIGS. 6A and 6B , the structure is different from that of the forgoing embodiments in that the FET 100 E includes multiple, i.e., three, round-shaped nano-wire channels 212 a , 212 b and 212 c , instead of the single nano-wire channel 12 or the two nano-wire channels 112 a and 112 b .",
"The structure 100 E includes a semiconductor substrate 110 .",
"Source/drain regions 214 are formed on the substrate 110 .",
"The source/drain regions 214 are formed of a stacked structure of a first SiGe layer 214 a , a first Si layer 214 b , a second SiGe layer 214 c , a second Si layer 214 d , a third SiGe layer 214 e , a third Si layer 214 f and a fourth SiGe layer 214 g sequentially stacked as shown.",
"The first, second, third and fourth SiGe layers 214 a , 214 c , 214 e and 214 g and the first, second and third Si layers 214 b , 214 d and 214 f can be epitaxial layers.",
"The first Si layer 214 b includes a first round-shaped nano-wire channel region 212 a extending along a longitudinal line X 3 across the structure between the source/drain regions 214 .",
"The second Si layer 214 d includes a second round-shaped nano-wire channel 212 b extending along a longitudinal line X 4 across the structure between the source/drain regions 214 .",
"The third Si layer 214 f includes a third round-shaped nano-wire channel 212 c extending along a longitudinal line X 5 across the structure between the source/drain regions 214 .",
"A portion of the substrate 110 protrudes above the surface of the substrate in the region beneath the nano-wire channel regions 212 a , 212 b and 212 c .",
"As noted in FIG. 6B , the first nano-wire channel 212 a and the protruding portion of the substrate 110 are separated by a distance d 1 .",
"Also, the second nano-wire channel region 212 b and the protruding portion of the substrate 110 are separated by a distance d 2 .",
"Also, the third nano-wire channel 212 c and the protruding portion of the substrate 110 are separated by a distance d 3 .",
"An isolation region 116 isolates the FET 100 E from other devices.",
"A gate dielectric layer 30 made of a material such as silicon oxide surrounds the first, second and third nano-wire channel regions 212 a , 212 b and 212 c .",
"The gate dielectric layer 30 also surrounds the protruding portion of the substrate.",
"A gate 20 made of a conductive material such as polysilicon, metal or a combination of polysilicon and metal surrounds the nano-wire channel regions 212 a , 212 b and 212 c .",
"The gate 20 is insulated from the nano-wire channels 212 a , 212 b and 212 c by the gate dielectric layer 30 .",
"[0075] FIG. 7 is a schematic cross-sectional view of another embodiment of the FET of FIG. 1 , corresponding to line A-A′ of FIG. 1 .",
"The device 100 F of FIG. 7 differs from that of FIGS. 6A and 6B in that, instead of the multiple-layer stack having the first, second, third and fourth SiGe layers 214 a , 214 c , 214 e and 214 g and the first, second and third Si layers 214 b , 214 d and 214 f , the device of FIG. 7 has only a single Si layer 214 h , which serves as the source/drain regions of the device and provides the round-shaped nano-wire channels 212 a , 212 b and 212 c of the device.",
"[0076] FIG. 8 is a logical flow diagram illustrating the process of forming the round-shaped nano-wire channels and gate of the FET according to the invention.",
"FIGS. 9A through 9D are schematic perspective views illustrating the steps in the process of forming the nano-wire channels and gate of the invention.",
"The process of forming the nano-wire channels, the gate and the FET of the invention described herein is applicable to any of the embodiments of the FET described herein.",
"Specifically, the formation process is applicable to a FET having any number of round-shaped nano-wire channels.",
"[0077] Referring to FIGS. 8 and 9A through 9 D, in step S 50 , an active Si pattern having a polygonal cross-sectional shape is formed.",
"For example, referring specifically to FIG. 9A , the active Si pattern 402 can have flat exterior surfaces 402 b and a substantially square shape 402 a in cross section.",
"[0078] Next, in step S 60 , a cleaning process is performed to remove any oxide that may have formed on the active Si pattern 402 .",
"[0079] Next, in step S 70 , etching is performed to remove square corners from the active pattern 402 .",
"An annealing step is performed to complete the round-shaped Si nano-wire channel 404 .",
"As shown in FIG. 9B , the channel 404 has a substantially round shape 404 a in cross section.",
"[0080] Next, in step S 80 , a gate dielectric layer 406 is formed surrounding the round-shaped nano-wire channel region 404 , as shown in FIG. 9C .",
"[0081] Next, in step S 90 , a gate electrode 408 is formed surrounding the gate dielectric layer 406 and the round-shaped or cylindrical Si nano-wire channel 404 , as shown in FIG. 9D .",
"The gate electrode 408 is made of a conductive material such as polysilicon, metal, or a combination of polysilicon and metal.",
"[0082] FIG. 10 is a detailed flow diagram illustrating the process of forming the round nano-wire channel 404 from the square nano-wire channel 402 .",
"FIG. 10 will be described below in detail.",
"[0083] FIGS. 11A through 11M are schematic perspective views illustrating steps in a process of manufacturing the FET of the invention, in accordance with an embodiment of the invention.",
"Referring to FIG. 11A , a silicon substrate 500 is provided.",
"A first silicon germanium (SiGe) layer 512 is formed on top of the substrate 500 .",
"The first SiGe layer 512 can have a thickness of 5-50 nm and can contain 15-20% germanium.",
"An active silicon layer 514 is formed over the first SiGe layer.",
"The silicon layer 514 is the layer of which the round-shaped nano-wire channel region of the FET will eventually be formed.",
"A second SiGe layer 516 is formed on the silicon layer 514 .",
"The second SiGe layer 516 can be formed to a thickness of 5-50 nm and can contain 5-10% germanium.",
"The second SiGe layer 516 may have a lower concentration of germanium such that during a subsequent etching process, the rate at which the upper layer of SiGe is consumed is lower to prevent damage to the silicon layer 514 to ensure a good nano-wire channel.",
"In one embodiment, the first and second SiGe layers 512 and 516 and the silicon layer 514 are grown epitaxially to the thickness of 5-50 nm.",
"[0084] A capping layer 518 is then formed over the second SiGe layer 516 .",
"The capping layer may be a buffer oxide layer made of a material having a high etch selectivity with respect to silicon nitride (SiN), such as silicon oxide, for a subsequent etching process.",
"Next, a hard mask layer, made of a material such as SiN, is formed on the buffer oxide layer 518 .",
"The hard mask layer is patterned such as by photolithographic and etching processes to form a hard mask pattern 520 on the buffer oxide layer 518 .",
"[0085] Referring to FIG. 11B , the structure is etched using the hard mask pattern 520 as an etching mask to form a STI trench 522 .",
"In one embodiment, the trench depth is 150-350 nm.",
"[0086] Referring to FIG. 11C , next, a shallow trench isolation (STI) 524 is formed in the trench 522 .",
"The STI is formed by a high density plasma (HDP) process to deposit an oxide.",
"After the HDP process, a chemical mechanical polishing (CMP) process is carried out to expose the top surface of the hard mask pattern 520 .",
"As shown in the drawing, the slurry used during the CMP process has a higher polishing rate on the HDP oxide 524 than it has on the hard mask pattern 520 such that a step is created between the HDP oxide 524 and the hard mask pattern 520 .",
"[0087] Next, referring to FIG. 11D , the hard mask pattern 520 and a portion of the HDP oxide is removed using phosphoric acid, leaving the buffer oxide layer 518 and the top surface of the HDP oxide 524 exposed on the top of the structure.",
"[0088] Next, referring to FIG. 11E , a second hard mask pattern 530 is formed on the top surface of the structure by forming a hard mask layer made of SiN and then applying photolithographic and etching processes to pattern the hard mask layer.",
"[0089] Next, referring to FIG. 11F , the structure is etched using the second hard mask pattern 530 as an etching mask to form a STI recess 532 .",
"The depth of the recess 532 is controlled to be deeper than the total thickness of the first and second SiGe layers 512 , 516 and the Si layer 514 .",
"That is, the recess 532 extends down into the structure deeper than the bottom of the epitaxial SiGe and Si layers.",
"The width of the remaining epitaxial SiGe and Si layers, as well as a portion of the substrate beneath the epitaxial layers is indicated in the figure as W 1 .",
"[0090] Next, referring to FIG. 11G , the remaining portion of the SiGe epitaxial layers 512 and 516 , the remaining portion of the active Si layer 514 a and the raised portion of the substrate beneath the epitaxial layers having the width W 1 are optionally trimmed by etching, such that the remaining portion of the epitaxial layers and the raised portion of the substrate beneath the epitaxial layers has a width W 2 .",
"The etching is preferably a chemical dry etch (CDE), which can be carried out, for example, at 400 W, 225 mTorr, 250 degrees C. for 20 seconds, in an atmosphere containing CF 4 and O 2 at flow rates of 60 and 150 seem, respectively.",
"The width W 2 is selected based on a desired size of the final nano-wire channel to be formed.",
"The CDE is performed to reduce the channel width to W 2 and to make the channel square in cross-section.",
"FIG. 11H is the structure of FIG. 11G rotated 90 degrees to clearly illustrate the resulting structure.",
"[0091] Next, referring to FIG. 11I , the sacrificial SiGe layers 512 and 516 on the top and bottom of the channel region 514 a are removed to completely expose the channel region 514 a .",
"It is also noted that a rectangular portion of the substrate 500 also remains beneath the channel region 514 a following this step.",
"This step is performed by a chemical wet etch using a chemical including CH 3 COOOH (or CH 3 COOH)+HF+DIW (deionized water) (+H2O2+surfactant, etc.).",
"[0092] Next, referring to FIG. 11J , the square cross-sectional channel region 514 a is formed into a nano-wire channel 514 b having a round or circular cross-section.",
"This is performed by etching and annealing the square cross-sectional channel region 514 a until it becomes the round nano-wire channel 514 b. [0093] FIG. 12 is a flow diagram illustrating the process of forming the round nano-wire channel 514 b from the square nano-wire channel 514 a .",
"First, an optional cleaning step S 100 is performed in an atmosphere of H2.",
"In one embodiment, the cleaning is performed in an atmosphere of 100% H2.",
"Alternatively, the atmosphere can also contain Ar and/or He with or without the H2.",
"In one embodiment, the cleaning is performed at a pressure of 0.1 to 10 Torr and a temperature of 600-900 degrees C. In one particular embodiment, the cleaning is performed at a temperature of 700-800 degrees C. The gas flow rate during the cleaning step can be 1-500 sccm, and the process time can be 1-5 minutes.",
"[0094] After the cleaning step, the four corners of the square nano-wire channel 514 a are etched in step 5200 .",
"The etching is carried out by introducing a combination of HCl and H2 gas into the process chamber.",
"In one particular embodiment, the gas flow rate of HCl during the etching is 100-2000 sccm, and the gas flow rate of the H2 is 100-2000 sccm.",
"The flow rate ratio of HCl:H2 can be in a range of 5:5 to 3:7.",
"In one particular embodiment, the flow rate ratio of HCl:H2 is 300 sccm: 500 sccm.",
"The etch temperature can be in the range of 600-900 degrees C., and the pressure can be 10-100 Torr.",
"The time of the etch can be in the range of 1-120 seconds.",
"[0095] The etch of step 5200 can be performed under one of at least three possible sets of conditions.",
"For a relatively long-duration, low-temperature etch, the etch temperature can be in the range of 600-700 degrees C. For a relatively short-duration, high-temperature etch, the etch temperature can be in the range of 850-900 degrees C. Between the two process conditions above, the middle-duration, middle-temperature etch can be carried out at a temperature between 750 and 820 degrees C. [0096] After the etching process, a low-temperature annealing is carried out in step S 300 to form the round-shaped nano-wire channel region 514 b .",
"The annealing is performed in an atmosphere of H2 gas.",
"In one embodiment, the annealing is performed at a pressure of 0.1-10 Torr.",
"If the pressure is lowered, the process time can also be lowered.",
"In one embodiment, the annealing is performed at a temperature of 600-900 degrees C. for a period of 10-800 seconds.",
"In one embodiment, the H 2 gas flow rate is 1-500 sccm.",
"In one particular embodiment, the annealing is carried out at a temperature of about 810 degrees C., at a pressure of 5 Torr and for a period of 500 seconds.",
"[0097] The etching and annealing steps can be repeated as many times as are needed to form the final round-shaped nano-wire channel 514 b .",
"Between the annealing step S 300 and the next repeated etching step S 200 , a purging step S 400 can be performed to remove the remaining annealing H 2 gas from the process chamber.",
"The purge can be performed using at least one of Ar, He and H 2 gas.",
"[0098] After the purging step S 400 , a determination is made in step S 500 as to whether the channel 514 b is the desired size and/or shape.",
"If the channel 514 b is of the proper shape and size, the process ends.",
"If not, the process returns to step S 200 to begin another cycle of etching, annealing (S 300 ) and optional purging (S 400 ).",
"[0099] Referring to FIG. 11K , after the round-shaped nano-wire channel 514 b is formed, a gate dielectric layer is formed on the structure, including surrounding the nano-wire channel 514 b .",
"The gate dielectric can be formed by growing SiO2 on the structure using O2 gas.",
"Next, a gate material such as polysilicon or a metal layer with polysilicon is formed surrounding the nano-wire channel 514 b .",
"Then the gate material is planarized such as by chemical mechanical polishing (CMP) to form the gate 540 surrounding the nano-wire channel 514 b. [0100] Next, referring to FIG. 11L , the second hard mask pattern 530 is removed.",
"FIG. 11M illustrates the final structure with the gate pattern 540 shown in phantom.",
"FIG. 11M shows the round-shaped nano-wire channel 514 b and the raised portion of the substrate 500 , which have both been formed into a round shape by the etching and annealing steps of the invention.",
"[0101] It is noted that this embodiment of manufacturing a FET is applicable to formation of any number of channel regions.",
"Where more channel regions are to be formed, more alternating layers of SiGe and Si are initially formed.",
"[0102] It should be noted that FIG. 2A corresponds to a cross-sectional view of FIG. 11L , taken along line IIa-IIa′ of FIG. 11L .",
"Likewise, FIG. 2B corresponds to a cross-sectional view of FIG. 11L , taken along line IIb-IIb′ of FIG. 11L .",
"[0103] FIGS. 12A through 12K are views illustrating steps in a process of manufacturing the FET of the invention, in accordance with another embodiment of the invention.",
"The initial steps used in the embodiment of FIGS. 12A through 12K are the same as those illustrated in the previously described embodiment for steps 11 A through 11 D. For the remaining steps, where a step is analogous to a step described in connection with the embodiment of FIGS. 11A through 11M , the step is carried out in similar fashion.",
"Therefore, description of those steps will not be repeated.",
"FIG. 12A-12F are schematic cross-sectional views of the structure of FIG. 11D , taken along line XII-XII′ of FIG. 11D , illustrating steps in the process of manufacturing a FET according to the embodiment of the invention.",
"FIGS. 12G-12K are schematic perspective views illustrating steps in the process of manufacturing a FET according to the embodiment of the invention.",
"Referring to FIG. 12A , the structure resulting after performance of steps 11 A through 11 D is illustrated.",
"[0104] Next, referring to FIG. 12B , a hard mask pattern 630 is formed on the structure.",
"The hard mask pattern 630 can be formed by patterning a layer of SiN.",
"[0105] Next, referring to FIG. 12C , recessed regions 632 are formed in the structure.",
"This can be performed by etching a trench to a depth deeper than the first epitaxial SiGe layer 512 using the hard mask pattern 630 as an etching mask.",
"[0106] Next, referring to FIG. 12D , the recess 632 is partially filled by epitaxially growing a Si layer 640 in the recess.",
"In one embodiment, the epitaxial Si layer 640 is grown to a depth higher than the second epitaxial SiGe layer 516 .",
"[0107] Next, referring to FIG. 12E , another hard mask pattern made of, for example, SiN is formed above the epitaxial Si layer 640 and adjacent to the hard mask pattern 630 .",
"[0108] Referring to FIGS. 12F and 12G , the hard mask pattern 630 is then removed, exposing the top or second epitaxial SiGe layer 516 and a portion of the top surface of the STI dielectric layer 524 .",
"[0109] Next, referring to FIG. 12H , the structure is etched to remove a portion of the STI dielectric layer 524 to form a damascene recessed region 532 to expose the sides of the stack of the first and second SiGe layers 512 and 516 , the Si layer 514 and a portion of the substrate 500 beneath the stacked epitaxial layers 512 , 514 and 516 .",
"[0110] Next, referring to FIG. 12I , the structure is etched, preferably by a chemical dry etch to trim the first and second sacrificial SiGe layers 512 and 516 , the Si layer 514 and the protruding portion of the substrate 500 .",
"The trimming also exposes a portion of the epitaxial Si layer 640 as shown.",
"[0111] Next, referring to FIG. 12J , the sacrificial SiGe layers 512 and 516 on the top and bottom of the channel region 514 a are removed to completely expose the channel region 514 a .",
"It is also noted that the rectangular protruding portion of the substrate 500 also remains beneath the channel region 514 a following this step.",
"This step is performed by a chemical wet etch using a chemical including CH 3 COOOH (or CH 3 COOH)+HF+DIW (deionized water) (+H2O2+surfactant, etc.).",
"[0112] Next, referring to FIG. 12K , the channel region 514 a is cleaned, etched and annealed in accordance with the description of FIG. 10 to form the round-shaped nano-wire channel region 514 b .",
"It is noted that in this embodiment, the source/drain regions of the FET are made from the single epitaxial Si layer 640 , as opposed to the stacked structure of epitaxial SiGe and Si layers.",
"It is also noted that this embodiment, like the previously described embodiment, is applicable to formation of any number of channel regions.",
"Where more channel regions are to be formed, more alternating layers of SiGe and Si are initially formed.",
"[0113] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims."
] |
This application claims priority to U.S. Provisional Application No. 60/256,483, filed Dec. 20, 2000.
FIELD OF INVENTION
The present invention relates to an inclusion complex formed between cyclodextrin and drospirenone, to methods of providing such an inclusion complex, and to a method of increasing the water solubility of drospirenone by providing such an inclusion complex. Moreover, the present invention relates to the use of said inclusion complex in pharmaceutical compositions for use as a medicament in the treatment of symptoms associated with menopause and in female contraception.
BACKGROUND OF THE INVENTION
Drospirenone (6β,7β;15β,16β-dimethylene-3-oxo-17α-pregn-4-ene-21,17-carbolactone), which may be prepared substantially as described in e.g. U.S. Pat. No. 4,129,564 or WO 98/06738, is only sparingly soluble in aqueous media at various pH values.
The water solubility of a compound is extremely pertinent with regards to its utility in industry, particularly in the pharmaceutical industry where there is a strong link between water solubility and bioavailability. The therapeutic efficiency of drospirenone may be improved by increasing its overall water solubility, thus providing for routes of administration alternative to those proceeding via the gastrointestinal tract, where absorption is slow and then rapidly cleared from circulating blood by the liver.
Cyclodextrins are known to solubilize nonpolar compounds and improve the absorption of certain compounds by forming complexes with said compounds. The cyclodextrins are frequently derivatized in order to improve the solubility or to accommodate appropriately the compound of interest. However, certain compounds are not well accommodated by the cavity of the some of the cyclodextrin molecules.
Drospirenone, in its uncomplexed form, is known from DE 26 52 761 in which its use as a diuretic compound is disclosed.
U.S. Pat. No. 4,596,795 discloses a complex between α-, β- and γ-cyclodextrins and derivatives thereof with testosterone, progesterone, and estradiol and the solubility of said complexes.
U.S. Pat. No. 5,885,978 relates to a composition comprising an adrenal cortical steroid and cyclodextrin prepared by clathrating the adrenal cortical steroid in the cyclodextrin using a homomixer.
U.S. Pat. No. 5,376,641 discloses a method of making a steroid water soluble by mixing a steroid and a branched beta cyclodextrin together in water for a period of 4 to 24 hours under ambient conditions.
U.S. Pat. No. 5,376,641 discloses a method for making a steroid water soluble by complexing the steroid with branched β-cyclodextrin.
U.S. Pat. No. 4,727,064 discloses a method of improving the dissolution properties of a steroid by forming a solid comprising at least one of testosterone, progesterone and estradiol as an inclusion complex with a poly-β-cyclodextrin and /or hydroxypropyl-β-cyclodextrin adapted for administration by buccal route.
FR 2 515 187 discloses inclusion complexes between γ-cyclodextrines and various steroids, such as a spironolactone steroid.
WO 96/02277 discloses pharmaceutical compositions containing cyclodextrin-clathrate complexes of steroid sexual hormones for protection against oxidative degradation of steroids.
SUMMARY OF THE INVENTION
The invention relates to an inclusion complex between cyclodextrin and 6β,7β;15β,16β-dimethylene-3-oxo-17α-pregn-4-ene-21,17-carbolactone (drospirenone).
The invention also relates to methods for producing an inclusion complex between cyclodextrin and drospirenone comprising combining drospirenone and cyclodextrin at a molar ratio of from 0.3:1 to 20:1, preferably 1:1, 2:1, 3:1, 4:1 or 5:1, most preferably 2:1 or 3:1, particularly 3:1.
One object of the present invention is to increase the water-solubility of drospirenone. The present invention thus further relates to methods for improving the solubility of drospirenone, said method comprising forming an inclusion complex between drospirenone and cyclodextrin.
In a further aspect of the invention, pharmaceutical compositions comprising an inclusion complex of drospirenone and cyclodextrin are anticipated. Consequently, the use of the inclusion complex between drospirenone and cyclodextrin as a medicament and for the preparation of a composition for female contraception or for the treatment of menopausal symptoms are defined herein. Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.
DETAILED DESCRIPTION OF THE INVENTION
The term “inclusion complex” is intended to mean a complex wherein at least a moiety of drospirenone has inserted itself, at least partially, into the cavity of cyclodextrin.
In efforts to improve the functional utility of drospirenone, research has led to a new chemical entity, an inclusion complex between cyclodextrin and drospirenone. The cyclodextrin, may be selected from α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin or derivatives thereof. Preferred embodiments of the present invention are that of a complex between drospirenone and β-cyclodextrin or derivatives thereof or a complex between drospirenone and γ-cyclodextrin or derivatives thereof, most preferably a complex between drospirenone and β-cyclodextrin or γ-cyclodextrin, particularly β-cyclodextrin.
The cyclodextrin, as stated, may be selected from the group comprised of α-cyclodextrin, β-cyclodextrin or γ-cyclodextrin, i.e. the 6-, 7-, or 8-sugar unit macrocycle, respectively. The cyclodextrin may be modified such that some or all of the primary or secondary hydroxyls of the macrocyle, or both, may be alkylated or acylated. Methods of modifying these alcohols are well known to the person skilled in the art and many derivatives are commercially available. The cyclodextrin may be modified such that one or more of the primary or secondary hydroxyls of the macrocyle, or both, may be alkylated or acylated. Methods of modifying these alcohols are well known to the person skilled in the art and many are commercially available. Thus, some or all of the hydroxyls of cyclodextrin may be substituted with an O—R group or an O—C(O)—R, wherein R is an optionally substituted C 1-6 alkyl, an optionally substituted C 2-6 alkenyl, an optionally substituted C 2-6 alkynyl, an optionally substituted aryl or heteroaryl group. R may be methyl, ethyl, propyl, butyl, pentyl, or hexyl group. Consequently, O—C(O)—R may be an acetate. Furthermore, R may be such as to derivatize cyclodextrin with the commonly employed 2-hydroxyethyl group, or 2-hydroxypropyl group. Moreover, the cyclodextrin alcohols may be per-benzylated, per-benzoylated, or benzylated or benzoylated on just one face of the macrocycle, or wherein only 1, 2, 3, 4, 5, or 6 hydroxyls are benzylated or benzoylated. The hydroxyl groups of cyclodextrin may be per-alkylated or per-acylated such as per-methylated or per-acetylated, or alkylated or acylated, such as methylated or acetylated, on just one face of the macrocycle, or wherein only 1, 2, 3, 4, 5, or 6 hydroxyls are alkylated or acylated, such as methylated or acetylated.
In a preferred embodiment of the invention, the inclusion complex is between β-cyclodextrin or γ-cyclodextrin and drospirenone. Most preferably, the inclusion complex is between β-cyclodextrin and drospirenone and in a further interesting embodiment thereof, the β-cyclodextrin is unmodified.
One or more drospirenone molecules may be included into the cavity of the cyclodextrin molecule. Conversely, one molecule of drospirenone may be included into the cavity of one or more cyclodextrin molecules. The inclusion complex may exist in a variety of molar ratios. The molar ratio between drospirenone and the cyclodextrin is dependent on a variety of physical factors during the formation of the inclusion complex. Furthermore, the molar ratio of the inclusion complex may be transitional and vary during its preparation. Given the inclusion of drospirenone can result from a variety of interactions with any number of functional groups or moieties of drospirenone, the depth at which drospirenone is included within the cavity of a cyclodextrin may vary. Furthermore, the size of the cavity, which depends on the selection of cyclodextrin (α-cyclodextrin, β-cyclodextrin or γ-cyclodextrin) and on whether the numerous free hydroxyl groups present on the periphery of the cavity of a cyclodextrin molecule are partially or fully derivatized, will influence the ability for drospirenone to include itself into the cavity. These factors, amongst others, influence the molar ratio of the inclusion complex.
Without being limited to a particular manner in which the inclusion complex is formed, it is presumed that the inclusion complex is an inclusion complex wherein hydrophobic interactions favour the inclusion of hydrophobic moieties from drospirenone into the cavity of a cyclodextrin molecule, given the relative hydrophobicity of the numerous alkyl groups in the cavity of the cyclodextrin.
Given the above-stated factors, and that the moiety of the drospirenone molecule which may include itself into the cyclodextrin molecule may vary, the molar ratio between drospirenone and the cyclodextrin, respectively, may be 1:1, 2:1, 3:1, 3:2, 1:2, 2:2, 2:3 or 1:3. Preferably a 1:1 or 1:2 molar ratio exists between drospirenone and cyclodextrin; namely, one molecule of drospirenone, or a moiety thereof, is at least partially inserted into the cavity of one cyclodextrin molecule or one molecule of drospirenone, or moieties thereof, is at least partially inserted into the cavity of two molecules of cyclodextrin. Alternatively, a 2:1 molar ratio may exist between drospirenone and cyclodextrin; namely, two molecules of drospirenone, or moieties thereof, are at least partially inserted into the cavity of one cyclodextrin molecule.
The term “solubility” in connection with drospirenone is intended to mean the solubility of the inclusion complex between drospirenone and cyclodextrin in water. The term “total solubility” relates to the drospirenone concentration in a phase solubility isotherm, namely to the solubility of uncomplexed and complexed drospirenone. The “total solubility” is a function of the cyclodextrin concentration.
Given one of the objects of the present invention is to increase the solubility and total solubility of drospirenone, it is preferred that the inclusion complex is such that the total water solubility of drospirenone at 20° C. is increased by a factor of at least 2, such as at least 2.5, at least 3, at least 3.5, or at least 4 compared to drospirenone in an uncomplexed form.
Correspondingly, it is preferred that the total solubility of drospirenone in water at 20° C. is increased to at least 9×10 −5 mol/L, such as at least 1×10 −4 mol/L, 2×10 −4 mol/L, 3×10 −4 mol/L or 3.5×10 −4 mol/L.
The inclusion complex may exist in the form of a hydrate containing varying amounts of water, such as between about 1% and 25% water. The degree of hydration may vary according to, amongst other reasons, the degree of substitution of the hydroxyls, the method of preparation and the molar ratio of the inclusion complex. The water content of the inclusion complex may depend on the manner in which the inclusion complex is stored, the temperature, pressure and relative humidity. Thus, any discussion on the solid state form of the drospirenone-cyclodextrin inclusion complex comprises the range of hydrates. The hydrate water is part of the crystal lattice and thus modifying the water content may change the crystal lattice and possibly some of the physical properties of the inclusion complex.
As is known to the person skilled in the art, cyclodextrin itself forms an inclusion complex with water. Thus, the cyclodextrin used in the preparation of the drospirenone-cyclodextrin inclusion complex may be in a hydrated form or in an anhydrous form.
A further object of the invention is to provide a method for producing an inclusion complex comprising the step of combining cyclodextrin and drospirenone at a molar ratio of from 0.3:1 to 20:1, preferably 1:1, 2:1, 3:1, 4:1 or 5:1, most preferably 2:1 or 3:1, particularly 3:1.
The term “solution” in connection with cyclodextrin or drospirenone and in connection with the preparation of an inclusion complex is intended to comprise embodiments wherein the solute, namely cyclodextrin or drospirenone, is fully or partially dissolved in the solvent so as to form a homogenous solution, a saturated solution, a super-saturated solution, a slurry or a suspension.
In the preparation of the inclusion complex according to the present invention, the combining of the components may be done using a solution of cyclodextrin, comprising organic solvent or an aqueous solution such as water. In some embodiments of the invention, the solvent comprises a mixture of water and an organic solvent. The organic solvent may be selected from any of those commonly used in organic synthesis such as, but not limited to, THF, methylene chloride, diethyl ether, petroleum ether, ethyl acetate, dioxane, DMF, DMSO, acetone, acetonitrile, ethanol, methanol, pyridine, or combinations thereof. Preferably, the organic solvent is miscible with water. Polar solvents are preferred such as water, methanol, ethanol, DMSO, DMF, and pyridine, most preferably water or ethanol, particularly water.
A solution of cyclodextrin, as described supra, in any concentration or degree of homogeneity, may be combined with solid drospirenone. Alternatively, the cyclodextrin solution may be combined with a solution of drospirenone. In the embodiment where a solution of cyclodextrin is combined with solid drospirenone, drospirenone may be in its micronized form.
In the embodiment where a solution of cyclodextrin is combined with a solution of drospirenone, drospirenone may be fully or partly dissolved in an organic solvent or water. Organic solvents may be selected from any of those known to the person skilled in the art such as, but not limited to, THF; methylene chloride, diethyl ether, petroleum ether, ethyl acetate, dioxane, DMF, DMSO, acetone, acetonitrile, ethanol, methanol, pyridine, or combinations thereof.
It follows that a solution of drospirenone, as described supra, in any degree of homogeneity and in any concentration may be combined with solid cyclodextrin in the preparation of an inclusion complex between cyclodextrin and drospirenone.
Alternatively, solid drospirenone and solid cyclodextrin may be combined in their solid forms and then combined with water or an organic solvent.
In a preferred embodiment of the invention, a method of producing an inclusion complex comprises the steps of dissolving cyclodextrin in water, optionally with the aid of heating, to form a cyclodextrin solution; dissolving drospirenone in a solvent selected from the group comprising of water and ethanol or mixtures thereof, optionally with the aid of heating, to form a drospirenone solution; combining the cyclodextrin solution and the drospirenone solution to form a combined solution; stirring the combined solution, preferably while keeping the solution at or below 25° C.; filtering the resultant precipitate; washing the precipitate with a solvent selected from the group consisting of water, ethanol, ether and acetone, preferably wherein the solvent is cooled to below 25° C.; optionally suspending the resultant solid in a solvent, preferably acetone, and washing the suspended material with a solvent selected from the group consisting of water, ethanol, ether and acetone, preferably wherein the solvent is cooled to below 25° C.; removing substantially all of the solvent from the solid material. Preferably, the solvent is removed by spray drying or alternatively by lyophilization.
The method of preparation may further comprise mechanical mixing, agitation or shaking, or heating of the solutions or combined components.
In embodiments of the invention wherein an organic solvent is used in the combination of drospirenone or cyclodextrin, the inclusion complex formed may contain one or more molecules of said solvents, depending on the method of drying, precipitation or crystallisation. The complex may alternatively exist in the form of a hydrate containing varying amounts of water.
A typical preparation of the drospirenone-cyclodextrin inclusion complex may be as follows: Drospirenone is dissolved in a solvent such as acetone or ethanol. The cyclodextrin is dissolved in water between 20 and 100° C., such as between 30 and 90° C., such as between 40 and 80° C., preferably between 40 and 60° C., such as at or near 40° C., 45° C., 50° C., 55° C. or 60° C. The drospirenone solution is added to the cyclodextrin solution and the obtained suspension is stirred at 20-30° C. for some hours, such as about 0.5 to 48 hours, then stirred at 2° C. for some hours. The crystallised product is isolated and dried. In an alternative process, the drospirenone solution is added to the cyclodextrin solution and the obtained suspension is stirred at temperatures below 25° C.
The inclusion complex may be prepared by methods described in or similar to those described in Examples 2, 3, 4, and 5.
The crystallised product may be washed with water, acetone and/or any other solvent in order to wash off non-complexed material. The solvent used to wash the crystallised product may be pre-cooled to below 25° C. This crystallised product may be dried over a drying agent such as P 2 O 5 or any other known to the person skilled in the art in a vacuum dessicator or cabinet for several hours or days. It may also be cooled in the dessicator during drying, or undergo spray drying or lyophillization.
A further objective of the invention is to provide a pharmaceutical composition comprising an inclusion complex of drospirenone and cyclodextrin as described supra together with one or more pharmaceutically acceptable carriers or excipients. The pharmaceutical composition may be adapted to be administered by oral, parental, mucosal, or topical, vaginal, subcutaneous or nasal administration. The composition may comprise from 0.1 mg to 10 mg of drospirenone, depending on its therapeutic application.
The drospirenone cyclodextrin inclusion complex may be used as a medicament. The drospirenone cyclodextrin inclusion complex may be used for the preparation of a pharmaceutical composition for female contraception or for the treatment of menopausal symptoms.
In suitable embodiments of the present invention, a pharmaceutical composition may comprise an inclusion complex between drospirenone and cyclodextrin and further comprise one or more therapeutically active substances. The therapeutically active substance is preferable a steroid. The therapeutically active substance may be complexed with cyclodextrin. Moreover, it may form part of an inclusion complex further comprising drospirenone. For instance, in the embodiment wherein drospirenone and cyclodextrin form an inclusion complex with a 1:2 or 1:3 molar ratio, respectively, said inclusion complex may further comprise a therapeutically active substance to form an inclusion complex with a 1:2: 1 or 1:3:1. Alternatively, said therapeutically active substance may be provide not as part of an inclusion complex. The pharmaceutical composition may comprise a drospirenone cyclodextrin inclusion complex, a therapeutically active substance such as estrogen or progestogen or a gestagen together with one or more pharmaceutically acceptable carriers or excipients.
Thus, one embodiment of the present invention is a three-component inclusion complex comprising drospirenone, one or more therapeutically active substances and cyclodextrin. The three-component complex may, for example, comprise drospirenone, cyclodextrin and a therapeutically active substance in molar ratio of 1:1:1, 1:2:1, 1:3:1, 2:2:1, 2:3:1, 2:3:2, 1:3:2. The molar ratio is limited in part by the size cavity of the cyclodextrin, by the nature of the active substance and by the size of moieties included into the cavity.
Three component complexes may be prepared by combining the therapeutically active substance in solid or solution form with either a solid or solution form of drospirenone, a solid or solution form of cyclodextrin, a solid mixture of cyclodextrin and drospirenone, or with a solution of cyclodextrin and drospirenone, namely the combined solution.
The entire disclosures of all applications, patents and publications, cited herein, and of U.S. Provisional Application Serial No. 60/256,483, filed Dec. 20, 2000, and of EP Application No. 00610134.9, filed Dec. 20, 2000, are hereby incorporated by reference.
BRIEF DESCRIPTION OF THE EXAMPLES
Example 1 compares the solubility of drospirenone in water with the solubility of a sample of an inclusion complex substantially consisting of a 1:1 molar ratio between β-cyclodextrin and drospirenone and to a sample consisting substantially of a 2:1 molar ratio between β-cyclodextrin and drospirenone. The example illustrates the increase in solubility of drospirenone by complexation with β-cyclodextrin. The example further discloses the stability of the 1:1 complex.
Examples 2 and 5 disclose two alternative methods for the preparation of a complex between drospirenone and γ-CD.
Examples 3 and 4 disclose two alternative methods for the preparation of a complex between drospirenone and β-CD.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 represents the structure of drospirenone and an embodiment of another component of the inclusion complex, cyclodextrin, namely β-cyclodextrin. β-cyclodextrin is a macrocycle consisting of 7 sugar units, whereas γ-cyclodextrin is a macrocycle consisting of 8 sugar units.
EXAMPLES
The foregoing and in the following examples are not a limitation upon the invention. In the examples, all temperatures are set forth uncorrected in degrees Celsius; and, unless otherwise indicated, all parts and percentages are by weight.
Example 1
Solubility of Drospirenone
The following data were obtained with the phase solubility diagram technique (PSD) In aqueous solutions at 20° C. The stability constants of the inclusion compound from β-CD and drospirenone are given.
Stability constant of the 1:1 complex
K 11 = 2.2 × 10 −4 M −1
Solubility of Drospirenone
S DP = 4.14 × 10 −5 mol/L (1.51 × 10 −2 g/L)
Solubility of 1:1 complex
S 1:1 = 3.88 × 10 −4 mol/L (0.516 g/L)
Solubility of 1:2 complex
S 1:2 = 3.79 × 10 −5 mol/L (0.1 g/L)
Example 2
Preparation of a Complex Between Drospirenone and γ-CD
30 mmol of the cyclodextrin are dissolved in 900 mL of water at 45° C. and, over the course of 30 min., 10 mmol of drospirenone, dissolved in 130 mL of ethanol are added dropwise. After washing with a further 5 mL of ethanol, cooling to room temperature, stirring at room temperature for 24 h and stirring in an ice bath (2° C.) for 4 h, the precipitate was filtered off with suction on a G4 frit. The resulting complex was then washed twice with 100 mL of ice water each time and once with 50 mL of ice-cooled acetone. It is then dried in a dessicator over phosphorous pentoxide.
Example 3
Preparation of a Complex Between Drospirenone and β-CD
24 mmol of the cyclodextrin are dissolved in 970 mL of water at 45° C. and, over the course of 30 min, 8 mmol of drospirenone, dissolved in 90 mL of ethanol are added dropwise. After washing with a further 5 mL of ethanol, cooling to room temperature, stirring at room temperature for 22 h and stirring in an ice bath (4° C.) for 3 h, the precipitate was filtered off with suction on a G4 frit. The resulting complex was then washed twice with 100 mL of ice water each time and twice with 50 mL of ice-cooled acetone. It is then dried in a dessicator over phosphorous pentoxide.
Example 4
Preparation of a Complex Between Drospirenone and β-CD
15.5 g of β-CD are dissolved in 1000 mL of water, heating if necessary. 1.468 g of drospirenone are weighed into the aqueous cyclodextrin solution. The suspension is stirred at room temperature for 72 h. It is then stirred at +2° C. for 3 h. The solid is filtered off with suction on a G4 frit and washed twice with 100 mL of water each time. The crystals are twice suspended in 50 mL of acetone and filtered off with suction each time. They are then washed with 100 mL of water. The moist crystals are dried in vacuo over phosphorous pentoxide.
Example 5
Preparation of a Complex Between Drospirenone and γ-CD
21.38 g of γ-CD are dissolved in 1000 mL of water, heating if necessary. 1.83 g of drospirenone are weighed into the aqueous cyclodextrin solution. The suspension is stirred at room temperature for 72 h. It is then stirred at +2° C. for 3 h. The solid is filtered off with suction on a G4 frit and washed twice with 100 mL of water each time. The crystals are twice suspended in 50 mL of acetone and filtered off with suction each time. They are then washed with 100 mL of water. The moist crystal are dried in vacuo over phosphorous pentoxide.
The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.
From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. | Described are inclusion complexes formed between cyclodextrin and drospirenone. In a specific embodiment of the invention, the cyclodextrin is β-cyclodextrin. The invention further relates to methods of providing such an inclusion complex, and to the use of said inclusion complex for improving the solubility of drospirenone, for providing pharmaceutical compositions, for use as a medicament in the treatment of symptoms associated with menopause and in female contraception. | Concisely explain the essential features and purpose of the concept presented in the passage. | [
"This application claims priority to U.S. Provisional Application No. 60/256,483, filed Dec. 20, 2000.",
"FIELD OF INVENTION The present invention relates to an inclusion complex formed between cyclodextrin and drospirenone, to methods of providing such an inclusion complex, and to a method of increasing the water solubility of drospirenone by providing such an inclusion complex.",
"Moreover, the present invention relates to the use of said inclusion complex in pharmaceutical compositions for use as a medicament in the treatment of symptoms associated with menopause and in female contraception.",
"BACKGROUND OF THE INVENTION Drospirenone (6β,7β;15β,16β-dimethylene-3-oxo-17α-pregn-4-ene-21,17-carbolactone), which may be prepared substantially as described in e.g. U.S. Pat. No. 4,129,564 or WO 98/06738, is only sparingly soluble in aqueous media at various pH values.",
"The water solubility of a compound is extremely pertinent with regards to its utility in industry, particularly in the pharmaceutical industry where there is a strong link between water solubility and bioavailability.",
"The therapeutic efficiency of drospirenone may be improved by increasing its overall water solubility, thus providing for routes of administration alternative to those proceeding via the gastrointestinal tract, where absorption is slow and then rapidly cleared from circulating blood by the liver.",
"Cyclodextrins are known to solubilize nonpolar compounds and improve the absorption of certain compounds by forming complexes with said compounds.",
"The cyclodextrins are frequently derivatized in order to improve the solubility or to accommodate appropriately the compound of interest.",
"However, certain compounds are not well accommodated by the cavity of the some of the cyclodextrin molecules.",
"Drospirenone, in its uncomplexed form, is known from DE 26 52 761 in which its use as a diuretic compound is disclosed.",
"U.S. Pat. No. 4,596,795 discloses a complex between α-, β- and γ-cyclodextrins and derivatives thereof with testosterone, progesterone, and estradiol and the solubility of said complexes.",
"U.S. Pat. No. 5,885,978 relates to a composition comprising an adrenal cortical steroid and cyclodextrin prepared by clathrating the adrenal cortical steroid in the cyclodextrin using a homomixer.",
"U.S. Pat. No. 5,376,641 discloses a method of making a steroid water soluble by mixing a steroid and a branched beta cyclodextrin together in water for a period of 4 to 24 hours under ambient conditions.",
"U.S. Pat. No. 5,376,641 discloses a method for making a steroid water soluble by complexing the steroid with branched β-cyclodextrin.",
"U.S. Pat. No. 4,727,064 discloses a method of improving the dissolution properties of a steroid by forming a solid comprising at least one of testosterone, progesterone and estradiol as an inclusion complex with a poly-β-cyclodextrin and /or hydroxypropyl-β-cyclodextrin adapted for administration by buccal route.",
"FR 2 515 187 discloses inclusion complexes between γ-cyclodextrines and various steroids, such as a spironolactone steroid.",
"WO 96/02277 discloses pharmaceutical compositions containing cyclodextrin-clathrate complexes of steroid sexual hormones for protection against oxidative degradation of steroids.",
"SUMMARY OF THE INVENTION The invention relates to an inclusion complex between cyclodextrin and 6β,7β;15β,16β-dimethylene-3-oxo-17α-pregn-4-ene-21,17-carbolactone (drospirenone).",
"The invention also relates to methods for producing an inclusion complex between cyclodextrin and drospirenone comprising combining drospirenone and cyclodextrin at a molar ratio of from 0.3:1 to 20:1, preferably 1:1, 2:1, 3:1, 4:1 or 5:1, most preferably 2:1 or 3:1, particularly 3:1.",
"One object of the present invention is to increase the water-solubility of drospirenone.",
"The present invention thus further relates to methods for improving the solubility of drospirenone, said method comprising forming an inclusion complex between drospirenone and cyclodextrin.",
"In a further aspect of the invention, pharmaceutical compositions comprising an inclusion complex of drospirenone and cyclodextrin are anticipated.",
"Consequently, the use of the inclusion complex between drospirenone and cyclodextrin as a medicament and for the preparation of a composition for female contraception or for the treatment of menopausal symptoms are defined herein.",
"Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.",
"DETAILED DESCRIPTION OF THE INVENTION The term “inclusion complex”",
"is intended to mean a complex wherein at least a moiety of drospirenone has inserted itself, at least partially, into the cavity of cyclodextrin.",
"In efforts to improve the functional utility of drospirenone, research has led to a new chemical entity, an inclusion complex between cyclodextrin and drospirenone.",
"The cyclodextrin, may be selected from α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin or derivatives thereof.",
"Preferred embodiments of the present invention are that of a complex between drospirenone and β-cyclodextrin or derivatives thereof or a complex between drospirenone and γ-cyclodextrin or derivatives thereof, most preferably a complex between drospirenone and β-cyclodextrin or γ-cyclodextrin, particularly β-cyclodextrin.",
"The cyclodextrin, as stated, may be selected from the group comprised of α-cyclodextrin, β-cyclodextrin or γ-cyclodextrin, i.e. the 6-, 7-, or 8-sugar unit macrocycle, respectively.",
"The cyclodextrin may be modified such that some or all of the primary or secondary hydroxyls of the macrocyle, or both, may be alkylated or acylated.",
"Methods of modifying these alcohols are well known to the person skilled in the art and many derivatives are commercially available.",
"The cyclodextrin may be modified such that one or more of the primary or secondary hydroxyls of the macrocyle, or both, may be alkylated or acylated.",
"Methods of modifying these alcohols are well known to the person skilled in the art and many are commercially available.",
"Thus, some or all of the hydroxyls of cyclodextrin may be substituted with an O—R group or an O—C(O)—R, wherein R is an optionally substituted C 1-6 alkyl, an optionally substituted C 2-6 alkenyl, an optionally substituted C 2-6 alkynyl, an optionally substituted aryl or heteroaryl group.",
"R may be methyl, ethyl, propyl, butyl, pentyl, or hexyl group.",
"Consequently, O—C(O)—R may be an acetate.",
"Furthermore, R may be such as to derivatize cyclodextrin with the commonly employed 2-hydroxyethyl group, or 2-hydroxypropyl group.",
"Moreover, the cyclodextrin alcohols may be per-benzylated, per-benzoylated, or benzylated or benzoylated on just one face of the macrocycle, or wherein only 1, 2, 3, 4, 5, or 6 hydroxyls are benzylated or benzoylated.",
"The hydroxyl groups of cyclodextrin may be per-alkylated or per-acylated such as per-methylated or per-acetylated, or alkylated or acylated, such as methylated or acetylated, on just one face of the macrocycle, or wherein only 1, 2, 3, 4, 5, or 6 hydroxyls are alkylated or acylated, such as methylated or acetylated.",
"In a preferred embodiment of the invention, the inclusion complex is between β-cyclodextrin or γ-cyclodextrin and drospirenone.",
"Most preferably, the inclusion complex is between β-cyclodextrin and drospirenone and in a further interesting embodiment thereof, the β-cyclodextrin is unmodified.",
"One or more drospirenone molecules may be included into the cavity of the cyclodextrin molecule.",
"Conversely, one molecule of drospirenone may be included into the cavity of one or more cyclodextrin molecules.",
"The inclusion complex may exist in a variety of molar ratios.",
"The molar ratio between drospirenone and the cyclodextrin is dependent on a variety of physical factors during the formation of the inclusion complex.",
"Furthermore, the molar ratio of the inclusion complex may be transitional and vary during its preparation.",
"Given the inclusion of drospirenone can result from a variety of interactions with any number of functional groups or moieties of drospirenone, the depth at which drospirenone is included within the cavity of a cyclodextrin may vary.",
"Furthermore, the size of the cavity, which depends on the selection of cyclodextrin (α-cyclodextrin, β-cyclodextrin or γ-cyclodextrin) and on whether the numerous free hydroxyl groups present on the periphery of the cavity of a cyclodextrin molecule are partially or fully derivatized, will influence the ability for drospirenone to include itself into the cavity.",
"These factors, amongst others, influence the molar ratio of the inclusion complex.",
"Without being limited to a particular manner in which the inclusion complex is formed, it is presumed that the inclusion complex is an inclusion complex wherein hydrophobic interactions favour the inclusion of hydrophobic moieties from drospirenone into the cavity of a cyclodextrin molecule, given the relative hydrophobicity of the numerous alkyl groups in the cavity of the cyclodextrin.",
"Given the above-stated factors, and that the moiety of the drospirenone molecule which may include itself into the cyclodextrin molecule may vary, the molar ratio between drospirenone and the cyclodextrin, respectively, may be 1:1, 2:1, 3:1, 3:2, 1:2, 2:2, 2:3 or 1:3.",
"Preferably a 1:1 or 1:2 molar ratio exists between drospirenone and cyclodextrin;",
"namely, one molecule of drospirenone, or a moiety thereof, is at least partially inserted into the cavity of one cyclodextrin molecule or one molecule of drospirenone, or moieties thereof, is at least partially inserted into the cavity of two molecules of cyclodextrin.",
"Alternatively, a 2:1 molar ratio may exist between drospirenone and cyclodextrin;",
"namely, two molecules of drospirenone, or moieties thereof, are at least partially inserted into the cavity of one cyclodextrin molecule.",
"The term “solubility”",
"in connection with drospirenone is intended to mean the solubility of the inclusion complex between drospirenone and cyclodextrin in water.",
"The term “total solubility”",
"relates to the drospirenone concentration in a phase solubility isotherm, namely to the solubility of uncomplexed and complexed drospirenone.",
"The “total solubility”",
"is a function of the cyclodextrin concentration.",
"Given one of the objects of the present invention is to increase the solubility and total solubility of drospirenone, it is preferred that the inclusion complex is such that the total water solubility of drospirenone at 20° C. is increased by a factor of at least 2, such as at least 2.5, at least 3, at least 3.5, or at least 4 compared to drospirenone in an uncomplexed form.",
"Correspondingly, it is preferred that the total solubility of drospirenone in water at 20° C. is increased to at least 9×10 −5 mol/L, such as at least 1×10 −4 mol/L, 2×10 −4 mol/L, 3×10 −4 mol/L or 3.5×10 −4 mol/L.",
"The inclusion complex may exist in the form of a hydrate containing varying amounts of water, such as between about 1% and 25% water.",
"The degree of hydration may vary according to, amongst other reasons, the degree of substitution of the hydroxyls, the method of preparation and the molar ratio of the inclusion complex.",
"The water content of the inclusion complex may depend on the manner in which the inclusion complex is stored, the temperature, pressure and relative humidity.",
"Thus, any discussion on the solid state form of the drospirenone-cyclodextrin inclusion complex comprises the range of hydrates.",
"The hydrate water is part of the crystal lattice and thus modifying the water content may change the crystal lattice and possibly some of the physical properties of the inclusion complex.",
"As is known to the person skilled in the art, cyclodextrin itself forms an inclusion complex with water.",
"Thus, the cyclodextrin used in the preparation of the drospirenone-cyclodextrin inclusion complex may be in a hydrated form or in an anhydrous form.",
"A further object of the invention is to provide a method for producing an inclusion complex comprising the step of combining cyclodextrin and drospirenone at a molar ratio of from 0.3:1 to 20:1, preferably 1:1, 2:1, 3:1, 4:1 or 5:1, most preferably 2:1 or 3:1, particularly 3:1.",
"The term “solution”",
"in connection with cyclodextrin or drospirenone and in connection with the preparation of an inclusion complex is intended to comprise embodiments wherein the solute, namely cyclodextrin or drospirenone, is fully or partially dissolved in the solvent so as to form a homogenous solution, a saturated solution, a super-saturated solution, a slurry or a suspension.",
"In the preparation of the inclusion complex according to the present invention, the combining of the components may be done using a solution of cyclodextrin, comprising organic solvent or an aqueous solution such as water.",
"In some embodiments of the invention, the solvent comprises a mixture of water and an organic solvent.",
"The organic solvent may be selected from any of those commonly used in organic synthesis such as, but not limited to, THF, methylene chloride, diethyl ether, petroleum ether, ethyl acetate, dioxane, DMF, DMSO, acetone, acetonitrile, ethanol, methanol, pyridine, or combinations thereof.",
"Preferably, the organic solvent is miscible with water.",
"Polar solvents are preferred such as water, methanol, ethanol, DMSO, DMF, and pyridine, most preferably water or ethanol, particularly water.",
"A solution of cyclodextrin, as described supra, in any concentration or degree of homogeneity, may be combined with solid drospirenone.",
"Alternatively, the cyclodextrin solution may be combined with a solution of drospirenone.",
"In the embodiment where a solution of cyclodextrin is combined with solid drospirenone, drospirenone may be in its micronized form.",
"In the embodiment where a solution of cyclodextrin is combined with a solution of drospirenone, drospirenone may be fully or partly dissolved in an organic solvent or water.",
"Organic solvents may be selected from any of those known to the person skilled in the art such as, but not limited to, THF;",
"methylene chloride, diethyl ether, petroleum ether, ethyl acetate, dioxane, DMF, DMSO, acetone, acetonitrile, ethanol, methanol, pyridine, or combinations thereof.",
"It follows that a solution of drospirenone, as described supra, in any degree of homogeneity and in any concentration may be combined with solid cyclodextrin in the preparation of an inclusion complex between cyclodextrin and drospirenone.",
"Alternatively, solid drospirenone and solid cyclodextrin may be combined in their solid forms and then combined with water or an organic solvent.",
"In a preferred embodiment of the invention, a method of producing an inclusion complex comprises the steps of dissolving cyclodextrin in water, optionally with the aid of heating, to form a cyclodextrin solution;",
"dissolving drospirenone in a solvent selected from the group comprising of water and ethanol or mixtures thereof, optionally with the aid of heating, to form a drospirenone solution;",
"combining the cyclodextrin solution and the drospirenone solution to form a combined solution;",
"stirring the combined solution, preferably while keeping the solution at or below 25° C.;",
"filtering the resultant precipitate;",
"washing the precipitate with a solvent selected from the group consisting of water, ethanol, ether and acetone, preferably wherein the solvent is cooled to below 25° C.;",
"optionally suspending the resultant solid in a solvent, preferably acetone, and washing the suspended material with a solvent selected from the group consisting of water, ethanol, ether and acetone, preferably wherein the solvent is cooled to below 25° C.;",
"removing substantially all of the solvent from the solid material.",
"Preferably, the solvent is removed by spray drying or alternatively by lyophilization.",
"The method of preparation may further comprise mechanical mixing, agitation or shaking, or heating of the solutions or combined components.",
"In embodiments of the invention wherein an organic solvent is used in the combination of drospirenone or cyclodextrin, the inclusion complex formed may contain one or more molecules of said solvents, depending on the method of drying, precipitation or crystallisation.",
"The complex may alternatively exist in the form of a hydrate containing varying amounts of water.",
"A typical preparation of the drospirenone-cyclodextrin inclusion complex may be as follows: Drospirenone is dissolved in a solvent such as acetone or ethanol.",
"The cyclodextrin is dissolved in water between 20 and 100° C., such as between 30 and 90° C., such as between 40 and 80° C., preferably between 40 and 60° C., such as at or near 40° C., 45° C., 50° C., 55° C. or 60° C. The drospirenone solution is added to the cyclodextrin solution and the obtained suspension is stirred at 20-30° C. for some hours, such as about 0.5 to 48 hours, then stirred at 2° C. for some hours.",
"The crystallised product is isolated and dried.",
"In an alternative process, the drospirenone solution is added to the cyclodextrin solution and the obtained suspension is stirred at temperatures below 25° C. The inclusion complex may be prepared by methods described in or similar to those described in Examples 2, 3, 4, and 5.",
"The crystallised product may be washed with water, acetone and/or any other solvent in order to wash off non-complexed material.",
"The solvent used to wash the crystallised product may be pre-cooled to below 25° C. This crystallised product may be dried over a drying agent such as P 2 O 5 or any other known to the person skilled in the art in a vacuum dessicator or cabinet for several hours or days.",
"It may also be cooled in the dessicator during drying, or undergo spray drying or lyophillization.",
"A further objective of the invention is to provide a pharmaceutical composition comprising an inclusion complex of drospirenone and cyclodextrin as described supra together with one or more pharmaceutically acceptable carriers or excipients.",
"The pharmaceutical composition may be adapted to be administered by oral, parental, mucosal, or topical, vaginal, subcutaneous or nasal administration.",
"The composition may comprise from 0.1 mg to 10 mg of drospirenone, depending on its therapeutic application.",
"The drospirenone cyclodextrin inclusion complex may be used as a medicament.",
"The drospirenone cyclodextrin inclusion complex may be used for the preparation of a pharmaceutical composition for female contraception or for the treatment of menopausal symptoms.",
"In suitable embodiments of the present invention, a pharmaceutical composition may comprise an inclusion complex between drospirenone and cyclodextrin and further comprise one or more therapeutically active substances.",
"The therapeutically active substance is preferable a steroid.",
"The therapeutically active substance may be complexed with cyclodextrin.",
"Moreover, it may form part of an inclusion complex further comprising drospirenone.",
"For instance, in the embodiment wherein drospirenone and cyclodextrin form an inclusion complex with a 1:2 or 1:3 molar ratio, respectively, said inclusion complex may further comprise a therapeutically active substance to form an inclusion complex with a 1:2: 1 or 1:3:1.",
"Alternatively, said therapeutically active substance may be provide not as part of an inclusion complex.",
"The pharmaceutical composition may comprise a drospirenone cyclodextrin inclusion complex, a therapeutically active substance such as estrogen or progestogen or a gestagen together with one or more pharmaceutically acceptable carriers or excipients.",
"Thus, one embodiment of the present invention is a three-component inclusion complex comprising drospirenone, one or more therapeutically active substances and cyclodextrin.",
"The three-component complex may, for example, comprise drospirenone, cyclodextrin and a therapeutically active substance in molar ratio of 1:1:1, 1:2:1, 1:3:1, 2:2:1, 2:3:1, 2:3:2, 1:3:2.",
"The molar ratio is limited in part by the size cavity of the cyclodextrin, by the nature of the active substance and by the size of moieties included into the cavity.",
"Three component complexes may be prepared by combining the therapeutically active substance in solid or solution form with either a solid or solution form of drospirenone, a solid or solution form of cyclodextrin, a solid mixture of cyclodextrin and drospirenone, or with a solution of cyclodextrin and drospirenone, namely the combined solution.",
"The entire disclosures of all applications, patents and publications, cited herein, and of U.S. Provisional Application Serial No. 60/256,483, filed Dec. 20, 2000, and of EP Application No. 00610134.9, filed Dec. 20, 2000, are hereby incorporated by reference.",
"BRIEF DESCRIPTION OF THE EXAMPLES Example 1 compares the solubility of drospirenone in water with the solubility of a sample of an inclusion complex substantially consisting of a 1:1 molar ratio between β-cyclodextrin and drospirenone and to a sample consisting substantially of a 2:1 molar ratio between β-cyclodextrin and drospirenone.",
"The example illustrates the increase in solubility of drospirenone by complexation with β-cyclodextrin.",
"The example further discloses the stability of the 1:1 complex.",
"Examples 2 and 5 disclose two alternative methods for the preparation of a complex between drospirenone and γ-CD.",
"Examples 3 and 4 disclose two alternative methods for the preparation of a complex between drospirenone and β-CD.",
"BRIEF DESCRIPTION OF THE FIGURES FIG. 1 represents the structure of drospirenone and an embodiment of another component of the inclusion complex, cyclodextrin, namely β-cyclodextrin.",
"β-cyclodextrin is a macrocycle consisting of 7 sugar units, whereas γ-cyclodextrin is a macrocycle consisting of 8 sugar units.",
"EXAMPLES The foregoing and in the following examples are not a limitation upon the invention.",
"In the examples, all temperatures are set forth uncorrected in degrees Celsius;",
"and, unless otherwise indicated, all parts and percentages are by weight.",
"Example 1 Solubility of Drospirenone The following data were obtained with the phase solubility diagram technique (PSD) In aqueous solutions at 20° C. The stability constants of the inclusion compound from β-CD and drospirenone are given.",
"Stability constant of the 1:1 complex K 11 = 2.2 × 10 −4 M −1 Solubility of Drospirenone S DP = 4.14 × 10 −5 mol/L (1.51 × 10 −2 g/L) Solubility of 1:1 complex S 1:1 = 3.88 × 10 −4 mol/L (0.516 g/L) Solubility of 1:2 complex S 1:2 = 3.79 × 10 −5 mol/L (0.1 g/L) Example 2 Preparation of a Complex Between Drospirenone and γ-CD 30 mmol of the cyclodextrin are dissolved in 900 mL of water at 45° C. and, over the course of 30 min.",
", 10 mmol of drospirenone, dissolved in 130 mL of ethanol are added dropwise.",
"After washing with a further 5 mL of ethanol, cooling to room temperature, stirring at room temperature for 24 h and stirring in an ice bath (2° C.) for 4 h, the precipitate was filtered off with suction on a G4 frit.",
"The resulting complex was then washed twice with 100 mL of ice water each time and once with 50 mL of ice-cooled acetone.",
"It is then dried in a dessicator over phosphorous pentoxide.",
"Example 3 Preparation of a Complex Between Drospirenone and β-CD 24 mmol of the cyclodextrin are dissolved in 970 mL of water at 45° C. and, over the course of 30 min, 8 mmol of drospirenone, dissolved in 90 mL of ethanol are added dropwise.",
"After washing with a further 5 mL of ethanol, cooling to room temperature, stirring at room temperature for 22 h and stirring in an ice bath (4° C.) for 3 h, the precipitate was filtered off with suction on a G4 frit.",
"The resulting complex was then washed twice with 100 mL of ice water each time and twice with 50 mL of ice-cooled acetone.",
"It is then dried in a dessicator over phosphorous pentoxide.",
"Example 4 Preparation of a Complex Between Drospirenone and β-CD 15.5 g of β-CD are dissolved in 1000 mL of water, heating if necessary.",
"1.468 g of drospirenone are weighed into the aqueous cyclodextrin solution.",
"The suspension is stirred at room temperature for 72 h. It is then stirred at +2° C. for 3 h. The solid is filtered off with suction on a G4 frit and washed twice with 100 mL of water each time.",
"The crystals are twice suspended in 50 mL of acetone and filtered off with suction each time.",
"They are then washed with 100 mL of water.",
"The moist crystals are dried in vacuo over phosphorous pentoxide.",
"Example 5 Preparation of a Complex Between Drospirenone and γ-CD 21.38 g of γ-CD are dissolved in 1000 mL of water, heating if necessary.",
"1.83 g of drospirenone are weighed into the aqueous cyclodextrin solution.",
"The suspension is stirred at room temperature for 72 h. It is then stirred at +2° C. for 3 h. The solid is filtered off with suction on a G4 frit and washed twice with 100 mL of water each time.",
"The crystals are twice suspended in 50 mL of acetone and filtered off with suction each time.",
"They are then washed with 100 mL of water.",
"The moist crystal are dried in vacuo over phosphorous pentoxide.",
"The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.",
"From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions."
] |
RELATED APPLICATIONS
This application is a continuation-in-part of copending application Ser. No. 09/255,954 filed Feb. 23, 1999 now pending.
FIELD OF THE INVENTION
This invention relates to the removal of surface portions of dead or living tissue, sometimes termed microdermal abrasion and more specifically relates to an improved apparatus and process for the abrasion of surface portions of human tissue by the controlled flow of abrasive particles.
BACKGROUND OF THE INVENTION
Apparatus for the microdermal abrasion of the surface of tissue (living or dead) is well known. In these processes, a stream of abrasive particles such as sand is applied to the surface of the tissue or skin through an opening in a hand held tool (termed a handpiece) which is sealed against the skin. The tool and the particle stream is controllably scanned over the area to be abraded. The abrading particles and the removed tissue are then collected by vacuum in the handpiece and are passed through and collected by a filter to prevent the escape of the abraded tissue and sand into the vacuum pump and ambient atmosphere.
The handpiece has taken many forms in the past but usually provides a first passage for conducting abrasive particles from a reservoir to the area to be treated and a second parallel channel for conducting the particles and abraded skin away from the area treated and into a disposal vessel.
A typical prior art apparatus is shown in U.S. Pat. No. 5,037,432. The hand-held head of this patent is a long tubular structure having an off-center hole which permits the application of an abrasive particle jet to an area to be treated, and the subsequent removal of the particles and abraded skin. The off-center outlet hole is arranged to be on the same axis as the input abrasive particle jet which then reaches the area to be treated at a 45° angle. The outlet jet channel facing the opening has a nozzle restriction. The abraded skin and used particles are then withdrawn through a parallel return vacuum channel which is connected to a vacuum pump through a filter.
The above described hand held tool has a number of drawbacks. Thus, because it is relatively long (longer than about 5 inches) it is difficult to manipulate easily over a curved surface area to be abraded, for example, the surface of a human face. Further, the vacuum pressure within the hand tool is not easily changed by the operator when a weaker or more forceful jet of abrasive particles is desired at particular locations on the surface area being abraded. Further, the handpiece is subject to clogging at the restricted outlet nozzle, requiring the operator frequently to stop the treatment and clear the nozzle.
The above described handpiece is provided with a removable and disposable tip or bell section which contains the output hole. Thus, the tip can be removed and disposed of and replaced by a new tip after the treatment of each individual. The tip is normally press-fit onto the body of the handpiece and is tightly sealed thereto to prevent accidental escape of abraded skin and loss of vacuum. Therefore, the tip is very difficult to remove and replace.
It would be very desirable to provide a handpiece for abrasion of living tissue which avoids the above problems.
The abrasive particles and tissue which are removed in prior art devices are collected in a filter placed between the handpiece outlet channel and the vacuum pump. Such a filtration system is shown in U.S. Pat. Nos. 5,100,412 and 5,207,234 in the name of Rosso. The filter shown therein is an inverted cup at the outlet opening of a waste receiving chamber. The outlet opening is connected to the vacuum pump line and contaminated particles and debris flow from the cup exterior toward its interior thus building up on the cup exterior. This filter tends to become quickly clogged and becomes more and more impervious to the flow of air therethrough. Consequently, the system must be frequently turned off and the filter must be cleaned sometimes during and frequently after each use.
It would be very desirable to provide a filtration system which does not require frequent cleaning or emptying.
SUMMARY OF THE INVENTION
In accordance with the invention a novel apparatus and process is provided which avoids the problems with prior art devices as stated above, and which provides added improved operation as well.
In accordance with a first feature of the invention, a novel filtration system is provided in which a large area cylindrical filter is disposed coaxially within a large volume container with an annular air outlet chamber defined between the cylindrical filter and the container. The annular outlet channel is connected to the vacuum pump of the system.
In operation, abrasion particles and skin are conveyed from the outlet channel of the hand held instrument to the interior of the cylindrical filter and are then entrapped within the large surface area interior of the filter. Filtered air then passes through the filter and into the annular low pressure area surrounding the filter and then into the vacuum pump. Because of the large area of the filter, it need not be replaced frequently and will commonly not require replacement until after about 50 uses (or 50 patient treatments).
A back-up emergency filter is coupled between the annular filter volume and vacuum pump to prevent the flow of abrasion particles to the pump in the event of a failure or accidental bypass of the main filter.
The novel cylindrical filter may be mounted between top and bottom flexible disks or flanges which have a larger diameter than the cylindrical filter to permit the easy and rapid replacement of a new filter assembly after a given time or number of operations. The used sand and removed tissue will be trapped within the filter and between the gaskets during this operation. Note that the gaskets may have connection nipples or simple connection openings for input and output conduits which enter the filter interior and annular chamber respectively.
As an alternative to the above cylindrical filter which is rigid, it is also possible to employ a removable paper bag type of filter which is clamped around the inlet conduit, providing similar benefits to those described above at lower cost.
A novel hand-held head or handpiece is also provided with a novel modified design from that of the prior art.
As a first feature of the novel handpiece, a screw-on tip of clear plastic is used which makes threaded engagement with the body of the tool. Thus the tip is easily removed from and replaced on the handpiece body after a single use. The tip is hemispherical in shape and has a sand-blast opening on its central axis. Sand input and output channels in the body extend parallel to the central axis and the axis of the tip and are displaced toward opposite sides of the central axis. Thus, the opening in the tip is on the central axis of the tool body but is displaced from the input and output channels. The sand will then sweep past the opening (and skin adjacent thereto) in its travel within the tip to abrade the skin. Moreover, the diameter of the sand input channel to the tip interior is relatively smaller than the output vacuum channel (for example, {fraction (1/16)} inch versus ⅛ inch respectively). This enables the quicker and easier withdrawal of used sand and skin particles from the interior vacuum chamber formed between the end of the body and the tip and aids in prevention of leakage of sand from the skin area being treated if the tip is removed from the area having treated. Note that in use, the hole in the tip is sealed against the skin area to preserve the vacuum and sand flow within the tip.
As a further feature of the novel handpiece, the entire body is shortened to a length less than about 3 inches. This makes it much easier to manipulate the tip over the surface being treated.
As a still further feature of the new handpiece, a small opening is provided in the side of the tip which can be easily covered by the finger of the operator. Thus, the vacuum pressure within the tip can be immediately changed by the operator without having to reach for the main pressure control at the main housing to which the handpiece is attached. It should be noted that this opening can also be placed in the handpiece body and can communicate with either the inlet or the outlet channel and still accomplish the stated function.
As a still further feature of the handpiece, the end of the channel carrying sand to the tip is not restricted by a nozzle, but is of the same diameter as the input channel or even flared out to a larger diameter to prevent clogging of the input channel. The flare may also be used at the end of the output channel adjacent the tip. It has been found that the elimination of the nozzle does not adversely affect the operation of the system.
As a further feature of the present invention, a novel large volume particle supply reservoir is provided in which, for example, a five pound supply of an abrasive, such as, irregularly shaped aluminum oxide particles of a maximum dimension less than about 120 microns and with sharp irregular edges is stored. A nipple at the bottom of the container is connected to an outlet tube, which in turn is coupled to a particle flow control valve which permits air flow into the conduit to carry the sand around the system with a controlled mass flow. The container can be easily replaced or replenished.
In accordance with an improvement of the present application, the screw-on tip has a central elongated barrier or separator extending along the axis of the tip to its opening to define sand input and outlet chambers along the length of the tip to increase the volume of sand which reaches and abrades the area being treated.
BRIEF DESCRIPTION OF THE DRAWING(S)
FIG. 1 is a schematic diagram of the novel system of the invention.
FIG. 2 is a schematic cross-sectional view of the novel filter structure of FIG. 1 .
FIG. 3 is a top view of FIG. 2 .
FIG. 4 is a cross-sectional view of a prior art handpiece.
FIG. 5 is an end view of the handpiece of FIG. 4 as seen from line 5 — 5 in FIG. 4 .
FIG. 6 is a sectional view of the handpiece of FIG. 4 as seen from line 6 — 6 in FIG. 4 .
FIG. 7 is a cross-sectional view of a novel handpiece containing many of the features of the present invention.
FIG. 8 is a sectional view of the handpiece of FIG. 7 as seen from line 8 — 8 in FIG. 7 .
FIG. 9 is an end view of FIG. 7 as seen from the line 9 — 9 in FIG. 7 .
FIG. 10 schematically shows a novel handpiece which contains a sand velocity control aperture in the tool tip.
FIG. 11 schematically shows a handpiece which contains a sand input channel which extends into the tip interior.
FIG. 12 schematically shows flares at the ends of the input and output channels in the handpiece to prevent clogging.
FIG. 13 is a perspective view of a preferred embodiment of the tip portion 32/90/110 of the preceding figures.
FIG. 14 is a side view of the tip portion of FIG. 13 .
FIG. 15 is a cross-sectional view of FIG. 14 taken across section line 15 — 15 in FIG. 14 .
FIG. 16 is an end view of FIG. 14 .
FIG. 17 is a perspective view of a preferred handpiece for the replaceable tip of FIGS. 13 to 16 .
FIG. 18 is a side view of the handpiece of FIG. 17 .
FIG. 19 is an end view of the handpiece of FIG. 18 .
DETAILED DESCRIPTION OF THE INVENTION
Referring first to FIG. 1, there is shown a supply container 20 , which can, for example, contain about 5 pounds of a suitable abrasive sand 21 , for example, aluminum oxide particles with very sharp edges and a non-critical maximum dimension of about 120 microns. An output particle supply line 22 which may be a plastic conduit of about ¼ inch O.D. is connected to a suitable connection nipple (not shown) on the bottom of can 20 . A particle flow control valve 23 is provided to control the air flow from the atmosphere into supply line 22 to move abrasive particles in the input conduit 30 of handpiece 31 ; moving sand faster when the valve is closed.
Handpiece 31 further includes a hemispherical shaped tip 32 which is removably connected to body 33 . The body 33 contains input channel 30 and output channel 34 which will be later described in detail. Channel 30 conventionally has a diameter of about ⅛ inch and channel 34 is conventionally about 1 inch in diameter.
Removable tip 32 is a hollow hemispheric structure having a diameter of about 1 inch, a length of about 1½ inch, and has a central aperture 35 on its axis. Typically, aperture 35 has a non-critical diameter of ¼ to ⅜ inch. In use, the aperture 35 is sealed against the surface to be treated and particles from conduit 30 pass by and abrade the skin exposed through aperture 35 . The used sand particles and abraded tissue are then removed through channel 34 and are directed to a novel filter 40 .
Filter 40 consists of a cylindrical metal container 41 (FIGS. 2 and 3) which may have a 6 inch diameter and contains a cylindrical pleated filter 42 which may be over-wrapped with a flat filter paper. A standard 3 pound coffee container has been used for can 41 . The filters are sized to ensure trapping of the 120 micron sized particles and the abraded tissue. The cylindrical filter 42 is fixed as by cementing at top and bottom to rubber flange disks 43 and 44 respectively best shown in FIGS. 2 and 3. These may be formed of a silicone rubber about ¼ inch thick. The top disk 43 has openings 45 and 46 which receive air outlet conduit 47 and an air-plus-particle inlet conduit 48 . Conduits 47 and 48 are fused or otherwise sealably connected to openings in disk 43 . Conduits 47 and 48 may be flexible plastic tubes with O.D.'s of ⅜ and ¼ inch respectively.
The disks 43 and 44 are press-fitted into the inner diameter of container 41 and can be glued to the container interior. They form a sealed annular chamber 50 which surrounds filter 42 and communicates with conduit 47 .
While filter 42 is shown as a rigid filter fixed between rubber disks 43 and 44 , it can be replaced by a simple filter bag suitably clamped to input conduit 48 .
In operation, waste particles and tissue flow from the handpiece and into filter 42 and are collected therein. Filtered air passes through the filter 42 , into the low pressure annular volume 50 and out through conduit 47 toward vacuum pump 60 . This filtered air also flows through an secondary back-up filter 55 which prevents flow of abrasive particles into vacuum pump 60 (a ⅓ horse power pump) if filter 40 is accidentally bypassed. A ⅜ inch conduit 61 connects filter 55 to pump 60 .
A pressure gauge 62 monitors the pressure at the input to pump 60 (reading from 0 to 100 KPA vacuum). The exhaust air from pump 60 is exhausted to the exterior atmosphere through muffler 65 . A valve 66 controls the vacuum in line 61 .
It will be noted that valves 23 and 66 along with selected other elements of the system may be housed in a control box (not shown). The filters 40 and 55 and reservoir 20 are suitably mounted for greatest convenience. The handpiece 31 is connected to the particle supply by the elongated and flexible supply line 22 , and to the filter 40 by a similar elongated flexible line 70 . Lines 22 and 70 ensure that an operator can manipulate the handpiece 31 as necessary for its use.
FIG. 4, 5 and 6 show a prior art type of handpiece 80 which can be used with the novel filter and system of FIGS. 1, 2 and 3 . The handpiece 80 consists of a solid plastic body 81 having a large diameter channel 82 which is coaxial with the axis of body 81 and a smaller diameter outflow channel 83 . A restrictive nozzle is commonly placed at the end of channel 82 . Body 80 has a length of about 5 inches and a reduced diameter end section 84 , about 1 inch long. An O-ring gasket 85 is fixed around the diameter of section 84 , at a point removed from the shoulder 86 . A rigid transparent plastic tip is fitted over gasket 85 to form a chamber 91 leading to a central hole or aperture 92 .
In use, the hole 92 is pressed (or sealed) against the skin area to be treated. Abrading particles flowing along channel 82 and in line and coaxial with hole 92 impinge on the skin exposed through hole 92 and the used particles and abraded skin are reflected from the skin and are withdrawn through channel 83 .
FIGS. 7, 8 and 9 show a handpiece in accordance with several of the features of the invention. A body 100 of rigid plastic, for example Teflon, has a central axis 101 (FIGS. 8 and 9) and off-center inlet and outlet channels 102 and 103 respectively. Note that these channels are reversed in relative sizes from those of FIG. 4 and are ⅛ inch and ¼ inch respectively.
The body 100 has a very short length, less than about 3 inch and has a reduced diameter threaded end section 105 . A sealing O-ring 106 is placed against shoulder 107 between the large diameter and small diameter sections of body 100 . A transparent plastic tip 110 is then threaded onto the threaded portion of body extension 105 and compresses O-ring 106 against shoulder 107 to create a seal. The tip 110 forms a vacuum chamber 111 interior spaced from the end of body 100 and has a central aperture 112 (FIGS. 7 and 9) which is about {fraction (5/16)} inch in diameter and is laterally off-set from the axis of channels 102 and 103 .
The novel shortened length of handpiece 100 makes it easier for an operator to manipulate the opening 112 over the skin of a patient. Further, the large output diameter of channel 103 improves the operation of the device and makes it easier to quickly evacuate particles from chamber 111 to ensure against loss of particles to atmosphere if the handpiece is removed from the skin of a subject, breaking the vacuum in chamber 111 .
As a further advantage over prior handpieces, the tip 110 can be easily detached and replaced by a new tip after use on a given patient by simply unscrewing the tip and screwing on a new one for the next patient. In the prior art structure of FIGS. 4, 5 and 6 , the press fit of tip 90 over seal 85 formed a tight fit making it difficult to remove the used tip and replace it with a new one.
FIGS. 10, 11 and 12 schematically show several novel features for handpiece 31 of FIG. 1 which can be used with the handpieces of FIGS. 4 to 9 . In FIG. 10, the tip 32 is shown with a small control opening 119 therein which can be easily closed by the operator's finger to increase the vacuum to produce a more forceful stream of abrasive particles against the skin being abraded when such added force is required. This can be done directly at the handpiece, without requiring the operator to reach for the equipment housing valve 66 in FIG. 1 .
It should be further noted that the same result can be obtained by placing the control opening in the body of the handpiece and in communication with either the interior of the tip or the input channel or the output channel.
FIG. 11 shows a modification in which a tube 120 is added to channel 30 in body 33 to extend the point of exit of new abrading particles closer to opening 35 and the skin being treated.
FIG. 12 shows a variation in which the ends of channels 30 and 34 are flared outward at diffuser regions 122 and 123 respectively. It has been found that these diffuser flares tend to prevent clogging of the channels 30 and 34 at their ends entering vacuum chamber 130 formed by tip 31 . Note that in prior art handpieces a restriction nozzle has been used at the outlet of channel 30 which has been found to aggravate clogging of the handpiece after a short time.
FIGS. 13 to 16 show a preferred embodiment of a novel disposable plastic tip 200 which contains a central dividing barrier to define air/sand inlet and outlet chambers and FIGS. 17 to 19 describe a preferred handpiece 300 for holding the tip 200 .
Referring first to FIGS. 13 to 16 , the tip 200 is of clear molded plastic and comprises an outer cylindrical body 201 which extends from a knurled base 202 and having an opening 203 which is coaxial with the central axis of the tip 200 . A thread 204 is formed at the interior end of base 202 . In accordance with an important feature of the invention, a central barrier 210 extends from the end of chamber 211 (FIG. 15) which receives the handpiece to the apertured end 203 of the tip 200 . The end of barrier 210 has a cut-out 212 (FIG. 15) which defines a connection channel adjacent the end of the tip between the two air/sand chambers 213 , 214 formed on opposite sides of the barrier 210 (FIG. 14 ). This novel barrier 210 has been found to substantially increase the volume of airborne sand to the tissue being treated, and the volume being withdrawn therefrom, to and from the handpiece.
FIGS. 17 to 18 show the preferred handpiece body 300 for the tip 200 . Handpiece body 300 is a unitary molded body and has an enlarged diameter base 301 from which a smaller diameter integral body portion 302 extends. The base of body portion 302 carries threads 303 which thread into the threads 204 of tip 200 , with body portion 302 entering and being fixed within volume 211 (FIG. 15) of tip 200 . A gasket can be compressed between the end of tip 200 and the shoulder 304 on base 301 when the tip 200 is threadably fixed to handpiece 300 . As in the prior embodiments, a small diameter inlet channel nozzle 310 (0.89 mm diameter) and a large diameter outlet channel nozzle 311 (1.9 mm diameter) are provided. These lead to connection nipples 312 and 313 respectively. Note that when the tip 200 is screwed onto hand piece 300 , the barrier 210 should bisect the openings of nozzles 310 and 311 .
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims. | A novel handpiece and system for abrasion of skin is disclosed. A short handpiece with a threadably removable tip is used. The opening in the tip is centered on the handpiece axis and a small diameter particle inlet channel and larger diameter outlet channel are both offset from the handpiece axis. A central blade or barrier within the tip divides the tip into two volumes which each communicate with the opening and respective ones of the inlet and outlet passages. A vacuum control opening is formed in the tip for easy control by the operator. Abrasive particles and removed tissue are applied to the interior of a cylindrical filter supported within a supporting container. The annular area between the container and this filter is connected through a secondary emergency filter to a vacuum pump. The cylindrical filter can be a flexible filter bag. A large source of abrasive particles is coupled to the handpiece inlet and the filter is coupled to the handpiece outlet. | Briefly describe the main idea outlined in the provided context. | [
"RELATED APPLICATIONS This application is a continuation-in-part of copending application Ser.",
"No. 09/255,954 filed Feb. 23, 1999 now pending.",
"FIELD OF THE INVENTION This invention relates to the removal of surface portions of dead or living tissue, sometimes termed microdermal abrasion and more specifically relates to an improved apparatus and process for the abrasion of surface portions of human tissue by the controlled flow of abrasive particles.",
"BACKGROUND OF THE INVENTION Apparatus for the microdermal abrasion of the surface of tissue (living or dead) is well known.",
"In these processes, a stream of abrasive particles such as sand is applied to the surface of the tissue or skin through an opening in a hand held tool (termed a handpiece) which is sealed against the skin.",
"The tool and the particle stream is controllably scanned over the area to be abraded.",
"The abrading particles and the removed tissue are then collected by vacuum in the handpiece and are passed through and collected by a filter to prevent the escape of the abraded tissue and sand into the vacuum pump and ambient atmosphere.",
"The handpiece has taken many forms in the past but usually provides a first passage for conducting abrasive particles from a reservoir to the area to be treated and a second parallel channel for conducting the particles and abraded skin away from the area treated and into a disposal vessel.",
"A typical prior art apparatus is shown in U.S. Pat. No. 5,037,432.",
"The hand-held head of this patent is a long tubular structure having an off-center hole which permits the application of an abrasive particle jet to an area to be treated, and the subsequent removal of the particles and abraded skin.",
"The off-center outlet hole is arranged to be on the same axis as the input abrasive particle jet which then reaches the area to be treated at a 45° angle.",
"The outlet jet channel facing the opening has a nozzle restriction.",
"The abraded skin and used particles are then withdrawn through a parallel return vacuum channel which is connected to a vacuum pump through a filter.",
"The above described hand held tool has a number of drawbacks.",
"Thus, because it is relatively long (longer than about 5 inches) it is difficult to manipulate easily over a curved surface area to be abraded, for example, the surface of a human face.",
"Further, the vacuum pressure within the hand tool is not easily changed by the operator when a weaker or more forceful jet of abrasive particles is desired at particular locations on the surface area being abraded.",
"Further, the handpiece is subject to clogging at the restricted outlet nozzle, requiring the operator frequently to stop the treatment and clear the nozzle.",
"The above described handpiece is provided with a removable and disposable tip or bell section which contains the output hole.",
"Thus, the tip can be removed and disposed of and replaced by a new tip after the treatment of each individual.",
"The tip is normally press-fit onto the body of the handpiece and is tightly sealed thereto to prevent accidental escape of abraded skin and loss of vacuum.",
"Therefore, the tip is very difficult to remove and replace.",
"It would be very desirable to provide a handpiece for abrasion of living tissue which avoids the above problems.",
"The abrasive particles and tissue which are removed in prior art devices are collected in a filter placed between the handpiece outlet channel and the vacuum pump.",
"Such a filtration system is shown in U.S. Pat. Nos. 5,100,412 and 5,207,234 in the name of Rosso.",
"The filter shown therein is an inverted cup at the outlet opening of a waste receiving chamber.",
"The outlet opening is connected to the vacuum pump line and contaminated particles and debris flow from the cup exterior toward its interior thus building up on the cup exterior.",
"This filter tends to become quickly clogged and becomes more and more impervious to the flow of air therethrough.",
"Consequently, the system must be frequently turned off and the filter must be cleaned sometimes during and frequently after each use.",
"It would be very desirable to provide a filtration system which does not require frequent cleaning or emptying.",
"SUMMARY OF THE INVENTION In accordance with the invention a novel apparatus and process is provided which avoids the problems with prior art devices as stated above, and which provides added improved operation as well.",
"In accordance with a first feature of the invention, a novel filtration system is provided in which a large area cylindrical filter is disposed coaxially within a large volume container with an annular air outlet chamber defined between the cylindrical filter and the container.",
"The annular outlet channel is connected to the vacuum pump of the system.",
"In operation, abrasion particles and skin are conveyed from the outlet channel of the hand held instrument to the interior of the cylindrical filter and are then entrapped within the large surface area interior of the filter.",
"Filtered air then passes through the filter and into the annular low pressure area surrounding the filter and then into the vacuum pump.",
"Because of the large area of the filter, it need not be replaced frequently and will commonly not require replacement until after about 50 uses (or 50 patient treatments).",
"A back-up emergency filter is coupled between the annular filter volume and vacuum pump to prevent the flow of abrasion particles to the pump in the event of a failure or accidental bypass of the main filter.",
"The novel cylindrical filter may be mounted between top and bottom flexible disks or flanges which have a larger diameter than the cylindrical filter to permit the easy and rapid replacement of a new filter assembly after a given time or number of operations.",
"The used sand and removed tissue will be trapped within the filter and between the gaskets during this operation.",
"Note that the gaskets may have connection nipples or simple connection openings for input and output conduits which enter the filter interior and annular chamber respectively.",
"As an alternative to the above cylindrical filter which is rigid, it is also possible to employ a removable paper bag type of filter which is clamped around the inlet conduit, providing similar benefits to those described above at lower cost.",
"A novel hand-held head or handpiece is also provided with a novel modified design from that of the prior art.",
"As a first feature of the novel handpiece, a screw-on tip of clear plastic is used which makes threaded engagement with the body of the tool.",
"Thus the tip is easily removed from and replaced on the handpiece body after a single use.",
"The tip is hemispherical in shape and has a sand-blast opening on its central axis.",
"Sand input and output channels in the body extend parallel to the central axis and the axis of the tip and are displaced toward opposite sides of the central axis.",
"Thus, the opening in the tip is on the central axis of the tool body but is displaced from the input and output channels.",
"The sand will then sweep past the opening (and skin adjacent thereto) in its travel within the tip to abrade the skin.",
"Moreover, the diameter of the sand input channel to the tip interior is relatively smaller than the output vacuum channel (for example, {fraction (1/16)} inch versus ⅛ inch respectively).",
"This enables the quicker and easier withdrawal of used sand and skin particles from the interior vacuum chamber formed between the end of the body and the tip and aids in prevention of leakage of sand from the skin area being treated if the tip is removed from the area having treated.",
"Note that in use, the hole in the tip is sealed against the skin area to preserve the vacuum and sand flow within the tip.",
"As a further feature of the novel handpiece, the entire body is shortened to a length less than about 3 inches.",
"This makes it much easier to manipulate the tip over the surface being treated.",
"As a still further feature of the new handpiece, a small opening is provided in the side of the tip which can be easily covered by the finger of the operator.",
"Thus, the vacuum pressure within the tip can be immediately changed by the operator without having to reach for the main pressure control at the main housing to which the handpiece is attached.",
"It should be noted that this opening can also be placed in the handpiece body and can communicate with either the inlet or the outlet channel and still accomplish the stated function.",
"As a still further feature of the handpiece, the end of the channel carrying sand to the tip is not restricted by a nozzle, but is of the same diameter as the input channel or even flared out to a larger diameter to prevent clogging of the input channel.",
"The flare may also be used at the end of the output channel adjacent the tip.",
"It has been found that the elimination of the nozzle does not adversely affect the operation of the system.",
"As a further feature of the present invention, a novel large volume particle supply reservoir is provided in which, for example, a five pound supply of an abrasive, such as, irregularly shaped aluminum oxide particles of a maximum dimension less than about 120 microns and with sharp irregular edges is stored.",
"A nipple at the bottom of the container is connected to an outlet tube, which in turn is coupled to a particle flow control valve which permits air flow into the conduit to carry the sand around the system with a controlled mass flow.",
"The container can be easily replaced or replenished.",
"In accordance with an improvement of the present application, the screw-on tip has a central elongated barrier or separator extending along the axis of the tip to its opening to define sand input and outlet chambers along the length of the tip to increase the volume of sand which reaches and abrades the area being treated.",
"BRIEF DESCRIPTION OF THE DRAWING(S) FIG. 1 is a schematic diagram of the novel system of the invention.",
"FIG. 2 is a schematic cross-sectional view of the novel filter structure of FIG. 1 .",
"FIG. 3 is a top view of FIG. 2 .",
"FIG. 4 is a cross-sectional view of a prior art handpiece.",
"FIG. 5 is an end view of the handpiece of FIG. 4 as seen from line 5 — 5 in FIG. 4 .",
"FIG. 6 is a sectional view of the handpiece of FIG. 4 as seen from line 6 — 6 in FIG. 4 .",
"FIG. 7 is a cross-sectional view of a novel handpiece containing many of the features of the present invention.",
"FIG. 8 is a sectional view of the handpiece of FIG. 7 as seen from line 8 — 8 in FIG. 7 .",
"FIG. 9 is an end view of FIG. 7 as seen from the line 9 — 9 in FIG. 7 .",
"FIG. 10 schematically shows a novel handpiece which contains a sand velocity control aperture in the tool tip.",
"FIG. 11 schematically shows a handpiece which contains a sand input channel which extends into the tip interior.",
"FIG. 12 schematically shows flares at the ends of the input and output channels in the handpiece to prevent clogging.",
"FIG. 13 is a perspective view of a preferred embodiment of the tip portion 32/90/110 of the preceding figures.",
"FIG. 14 is a side view of the tip portion of FIG. 13 .",
"FIG. 15 is a cross-sectional view of FIG. 14 taken across section line 15 — 15 in FIG. 14 .",
"FIG. 16 is an end view of FIG. 14 .",
"FIG. 17 is a perspective view of a preferred handpiece for the replaceable tip of FIGS. 13 to 16 .",
"FIG. 18 is a side view of the handpiece of FIG. 17 .",
"FIG. 19 is an end view of the handpiece of FIG. 18 .",
"DETAILED DESCRIPTION OF THE INVENTION Referring first to FIG. 1, there is shown a supply container 20 , which can, for example, contain about 5 pounds of a suitable abrasive sand 21 , for example, aluminum oxide particles with very sharp edges and a non-critical maximum dimension of about 120 microns.",
"An output particle supply line 22 which may be a plastic conduit of about ¼ inch O.D. is connected to a suitable connection nipple (not shown) on the bottom of can 20 .",
"A particle flow control valve 23 is provided to control the air flow from the atmosphere into supply line 22 to move abrasive particles in the input conduit 30 of handpiece 31 ;",
"moving sand faster when the valve is closed.",
"Handpiece 31 further includes a hemispherical shaped tip 32 which is removably connected to body 33 .",
"The body 33 contains input channel 30 and output channel 34 which will be later described in detail.",
"Channel 30 conventionally has a diameter of about ⅛ inch and channel 34 is conventionally about 1 inch in diameter.",
"Removable tip 32 is a hollow hemispheric structure having a diameter of about 1 inch, a length of about 1½ inch, and has a central aperture 35 on its axis.",
"Typically, aperture 35 has a non-critical diameter of ¼ to ⅜ inch.",
"In use, the aperture 35 is sealed against the surface to be treated and particles from conduit 30 pass by and abrade the skin exposed through aperture 35 .",
"The used sand particles and abraded tissue are then removed through channel 34 and are directed to a novel filter 40 .",
"Filter 40 consists of a cylindrical metal container 41 (FIGS.",
"2 and 3) which may have a 6 inch diameter and contains a cylindrical pleated filter 42 which may be over-wrapped with a flat filter paper.",
"A standard 3 pound coffee container has been used for can 41 .",
"The filters are sized to ensure trapping of the 120 micron sized particles and the abraded tissue.",
"The cylindrical filter 42 is fixed as by cementing at top and bottom to rubber flange disks 43 and 44 respectively best shown in FIGS. 2 and 3.",
"These may be formed of a silicone rubber about ¼ inch thick.",
"The top disk 43 has openings 45 and 46 which receive air outlet conduit 47 and an air-plus-particle inlet conduit 48 .",
"Conduits 47 and 48 are fused or otherwise sealably connected to openings in disk 43 .",
"Conduits 47 and 48 may be flexible plastic tubes with O.D.'s of ⅜ and ¼ inch respectively.",
"The disks 43 and 44 are press-fitted into the inner diameter of container 41 and can be glued to the container interior.",
"They form a sealed annular chamber 50 which surrounds filter 42 and communicates with conduit 47 .",
"While filter 42 is shown as a rigid filter fixed between rubber disks 43 and 44 , it can be replaced by a simple filter bag suitably clamped to input conduit 48 .",
"In operation, waste particles and tissue flow from the handpiece and into filter 42 and are collected therein.",
"Filtered air passes through the filter 42 , into the low pressure annular volume 50 and out through conduit 47 toward vacuum pump 60 .",
"This filtered air also flows through an secondary back-up filter 55 which prevents flow of abrasive particles into vacuum pump 60 (a ⅓ horse power pump) if filter 40 is accidentally bypassed.",
"A ⅜ inch conduit 61 connects filter 55 to pump 60 .",
"A pressure gauge 62 monitors the pressure at the input to pump 60 (reading from 0 to 100 KPA vacuum).",
"The exhaust air from pump 60 is exhausted to the exterior atmosphere through muffler 65 .",
"A valve 66 controls the vacuum in line 61 .",
"It will be noted that valves 23 and 66 along with selected other elements of the system may be housed in a control box (not shown).",
"The filters 40 and 55 and reservoir 20 are suitably mounted for greatest convenience.",
"The handpiece 31 is connected to the particle supply by the elongated and flexible supply line 22 , and to the filter 40 by a similar elongated flexible line 70 .",
"Lines 22 and 70 ensure that an operator can manipulate the handpiece 31 as necessary for its use.",
"FIG. 4, 5 and 6 show a prior art type of handpiece 80 which can be used with the novel filter and system of FIGS. 1, 2 and 3 .",
"The handpiece 80 consists of a solid plastic body 81 having a large diameter channel 82 which is coaxial with the axis of body 81 and a smaller diameter outflow channel 83 .",
"A restrictive nozzle is commonly placed at the end of channel 82 .",
"Body 80 has a length of about 5 inches and a reduced diameter end section 84 , about 1 inch long.",
"An O-ring gasket 85 is fixed around the diameter of section 84 , at a point removed from the shoulder 86 .",
"A rigid transparent plastic tip is fitted over gasket 85 to form a chamber 91 leading to a central hole or aperture 92 .",
"In use, the hole 92 is pressed (or sealed) against the skin area to be treated.",
"Abrading particles flowing along channel 82 and in line and coaxial with hole 92 impinge on the skin exposed through hole 92 and the used particles and abraded skin are reflected from the skin and are withdrawn through channel 83 .",
"FIGS. 7, 8 and 9 show a handpiece in accordance with several of the features of the invention.",
"A body 100 of rigid plastic, for example Teflon, has a central axis 101 (FIGS.",
"8 and 9) and off-center inlet and outlet channels 102 and 103 respectively.",
"Note that these channels are reversed in relative sizes from those of FIG. 4 and are ⅛ inch and ¼ inch respectively.",
"The body 100 has a very short length, less than about 3 inch and has a reduced diameter threaded end section 105 .",
"A sealing O-ring 106 is placed against shoulder 107 between the large diameter and small diameter sections of body 100 .",
"A transparent plastic tip 110 is then threaded onto the threaded portion of body extension 105 and compresses O-ring 106 against shoulder 107 to create a seal.",
"The tip 110 forms a vacuum chamber 111 interior spaced from the end of body 100 and has a central aperture 112 (FIGS.",
"7 and 9) which is about {fraction (5/16)} inch in diameter and is laterally off-set from the axis of channels 102 and 103 .",
"The novel shortened length of handpiece 100 makes it easier for an operator to manipulate the opening 112 over the skin of a patient.",
"Further, the large output diameter of channel 103 improves the operation of the device and makes it easier to quickly evacuate particles from chamber 111 to ensure against loss of particles to atmosphere if the handpiece is removed from the skin of a subject, breaking the vacuum in chamber 111 .",
"As a further advantage over prior handpieces, the tip 110 can be easily detached and replaced by a new tip after use on a given patient by simply unscrewing the tip and screwing on a new one for the next patient.",
"In the prior art structure of FIGS. 4, 5 and 6 , the press fit of tip 90 over seal 85 formed a tight fit making it difficult to remove the used tip and replace it with a new one.",
"FIGS. 10, 11 and 12 schematically show several novel features for handpiece 31 of FIG. 1 which can be used with the handpieces of FIGS. 4 to 9 .",
"In FIG. 10, the tip 32 is shown with a small control opening 119 therein which can be easily closed by the operator's finger to increase the vacuum to produce a more forceful stream of abrasive particles against the skin being abraded when such added force is required.",
"This can be done directly at the handpiece, without requiring the operator to reach for the equipment housing valve 66 in FIG. 1 .",
"It should be further noted that the same result can be obtained by placing the control opening in the body of the handpiece and in communication with either the interior of the tip or the input channel or the output channel.",
"FIG. 11 shows a modification in which a tube 120 is added to channel 30 in body 33 to extend the point of exit of new abrading particles closer to opening 35 and the skin being treated.",
"FIG. 12 shows a variation in which the ends of channels 30 and 34 are flared outward at diffuser regions 122 and 123 respectively.",
"It has been found that these diffuser flares tend to prevent clogging of the channels 30 and 34 at their ends entering vacuum chamber 130 formed by tip 31 .",
"Note that in prior art handpieces a restriction nozzle has been used at the outlet of channel 30 which has been found to aggravate clogging of the handpiece after a short time.",
"FIGS. 13 to 16 show a preferred embodiment of a novel disposable plastic tip 200 which contains a central dividing barrier to define air/sand inlet and outlet chambers and FIGS. 17 to 19 describe a preferred handpiece 300 for holding the tip 200 .",
"Referring first to FIGS. 13 to 16 , the tip 200 is of clear molded plastic and comprises an outer cylindrical body 201 which extends from a knurled base 202 and having an opening 203 which is coaxial with the central axis of the tip 200 .",
"A thread 204 is formed at the interior end of base 202 .",
"In accordance with an important feature of the invention, a central barrier 210 extends from the end of chamber 211 (FIG.",
"15) which receives the handpiece to the apertured end 203 of the tip 200 .",
"The end of barrier 210 has a cut-out 212 (FIG.",
"15) which defines a connection channel adjacent the end of the tip between the two air/sand chambers 213 , 214 formed on opposite sides of the barrier 210 (FIG.",
"14 ).",
"This novel barrier 210 has been found to substantially increase the volume of airborne sand to the tissue being treated, and the volume being withdrawn therefrom, to and from the handpiece.",
"FIGS. 17 to 18 show the preferred handpiece body 300 for the tip 200 .",
"Handpiece body 300 is a unitary molded body and has an enlarged diameter base 301 from which a smaller diameter integral body portion 302 extends.",
"The base of body portion 302 carries threads 303 which thread into the threads 204 of tip 200 , with body portion 302 entering and being fixed within volume 211 (FIG.",
"15) of tip 200 .",
"A gasket can be compressed between the end of tip 200 and the shoulder 304 on base 301 when the tip 200 is threadably fixed to handpiece 300 .",
"As in the prior embodiments, a small diameter inlet channel nozzle 310 (0.89 mm diameter) and a large diameter outlet channel nozzle 311 (1.9 mm diameter) are provided.",
"These lead to connection nipples 312 and 313 respectively.",
"Note that when the tip 200 is screwed onto hand piece 300 , the barrier 210 should bisect the openings of nozzles 310 and 311 .",
"Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art.",
"It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims."
] |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based on Provisional Application Ser. No. 60/961,128, filed Jul. 18, 2007 to Van Lloyd hall, the disclosure of which is incorporated herein by reference and to which priority is claimed.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX
Not Applicable
FIELD OF THE INVENTION
The present invention relates to allowing a game hunter to find a downed game, or, at least, the blood trail, and, more particularly, to do so with accuracy, reducing the time searching for downed game.
BACKGROUND OF THE INVENTION
The hunting party has made all of the necessary preparations and plans. Camping, food, change of clothes, ammunition. You rise early, well before the sun. You eat breakfast while going over the logistics . . . who will drive the deer (elk, moose, boar, etc. . . . ) to you who will be sitting on the ridge, waiting to take the shot. With breakfast and plans in place, you leave to carry out this carefully laid plan for the hunt. Everything is going well. You climb to your spotting post and wait. Finally, your target is there. You raise your rifle (or bow), take aim, squeeze off a shot and watch your game falter. This is where the real hunt begins and time is of the essence. You must find the deer, make sure that there is no suffering and save the meat.
You leave your shooting post, climb down the hill and go right to the spot you are sure the game was standing when you shot it. You made notes about what to look for. The tall lodge pole pine. The three Aspens on the right of the big rock. You are sure this is the spot. You search and search for a blood tail, any sign. The rest of the hunting party finds you and join in the search. You all spread out. After many crucial hours searching, you have to call it a night. The hunting party returns to camp, worries about the animal being in pain, and all get a restless nights sleep, only to rise in the morning and head back out to search again.
The plan is, you will go back to the ridge where you shot from and guide the rest of the hunting party in the search. After another day of hunting, someone finally finds the blood trail. You follow this trail, which leads you several hundred yards to the fallen deer, a healthy four (4) point. Its been a warm Autumn. After this many hours dead, in the sun, the meat is already rotten. The animal is wasted because it took so long to locate, and signs there show a great deal of suffering before the animal finally died.
OR;
It snows. HARD. All night. You call off the search because there is too much snow to be hiking around looking for a fallen animal.
OR;
You are so excited to have finally been able to shoot at anything, you take off down the hill before remembering to find your identifying markers and you realized that you have no idea where to begin looking.
A search on the internet will take you to any number of articles on just how to track your game, once shot. The suggestions are widely subjective, and center on being able to identify the exact spot your game was standing when it was shot. In many situations, there is simply a lack of distinct identifying markers.
BRIEF SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a Fallen Game Locator to aid the hunter in locating the precise location that game was when shot. A cylindrical cone shaped device with fluorescent or brightly colored rings on the outside, a target sighting viewer tube through the center of the cone shaped device and the back plate, and, secured to a riser so as to enable being seen from multiple locations at a distance with the naked eye, a scope or binoculars.
An accessory for the hunter, which is light weight, virtually unnoticeable to pack or transport, simple to use and understand, and yet, extremely precise in pointing and guiding the hunter to the exact location game was when shot. By correctly pointing this device to the exact location game was when shot, and then simply following the markers or rings on the exterior of the apparatus as stated in the directions for use, will lead the hunter to the site where game was when shot, thus, enabling the hunter to retrieve the meat expeditiously and reduce spoilage of shot game due to inability to locate game after it has been shot. If made of biodegradable material, minute to no detectable environmental impact occurs with the use of this device.
It is therefore an object of the invention to be pointed or aimed directly to the site where game was when it was shot.
It is another object of the invention, through the application of exterior markers or rings, to direct the hunter directly to the site where game was when it was shot, according to the appearance of the markers or rings from any given view.
It is another object of the invention to reduce the time and effort in finding the site where game was when shot.
It is another object of the invention to assist the hunter in the prompt location of shot game, enabling a quick end to the suffering of the shot animal and the safe retrieval of the meat.
BRIEF DESCRIPTION OF THE DRAWINGS
A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when considered in conjunction with the subsequent, detailed description, in which:
FIG. 1 is an exploded view of a fallen game locator;
FIG. 2 is a side and front detail view of the sighting viewer tube of the fallen game locator;
FIG. 3 is a rear view of the back plate, showing placement of sighting viewer tube in the center of the back plate which is affixed at or in the large opening of the cone shaped object of the fallen game locator;
FIG. 4 is a side detail view of the fallen game locator, a cone shaped object, detailing different colored markers or rings, the number and/or color of rings not limited to depiction herein, encircling the exterior of the sight cone; and,
FIG. 5 is a side and front view of a fallen game locator sight cone showing an example of detail relating to the colored rings or markers on the exterior of said cone.
For purposes of clarity and brevity, like elements and components will bear the same designations and numbering throughout the FIGURES.
Throughout this Non-provisional patent application, the number of rings and the colors stated are suggestive in nature and used herein for suggested and visual purposes and in no way depict, or limit any set number of markers or rings nor any set measurement of any part of the subject of the invention, or, any set use of colors as the exterior markers or rings.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an exploded view of all essential elements of the fallen game locator. This consists of the sight cone 10 encircled with one (1) section each, of five (5) chosen fluorescent or very bright colors; color A 13 , color B 14 , color C 15 , color D 16 , and color E 17 , as well as the sighting viewer tube 11 and the back plate 12 .
The sight cone 10 should be of ample size in length and diameter to be seen from a distance with the naked eye, a scope, or binoculars. The sight cone 10 is placed or fastened on a riser or surface that will allow it to be seen from a distance with the naked eye, a scope, or binoculars. The sight cone 10 is divided evenly five (5) times, stated only to provide a visual reference and not to limit the invention in any way, from the front tip to the rear opening with colored rings. Each of the five (5) colored rings; color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , number of rings being used for example herein, is a different fluorescent or bright color that would be easily seen from a distance with the naked eye, a scope, or binoculars.
The sight cone 10 is capped off at the large opening with the back plate 12 . The back plate 12 has a hole in the center, similar in size to the exterior diameter of the sighting viewer tube 11 . The sighting viewer tube 11 is placed in and through the sight cone 10 from the front small tip to and through the back plate 12 , being inserted in the hole in the exact center of the back plate 12 .
FIG. 2 is a side and front view of a sighting viewer tube 11 . The sighting viewer tube 11 is inserted in and through the sight cone 10 , extending from beyond the back plate 12 to the front tip of the sight cone 10 . The sighting viewer tube 11 is small in diameter, but large enough that a person with normal eyesight can look through it to a point a distance away. The exterior dimension of the sighting viewer tube 11 is similar in size to the opening in the back plate 12 and the front tip of the sight cone 10 .
FIG. 3 is a back plate 12 detail of a fallen game locator showing placement of sighting viewer tube 11 in the center of the back plate 12 . The exterior dimension of the back plate 12 is slightly less than the interior dimension of the sight cone 10 . The hole in the center of the back plate 12 is similar in dimension as the exterior dimension of the sighting viewer tube 11 .
FIG. 4 is a side detail view of five (5) colored rings, which number and color of rings and suggested only for purpose of reference in this application, encircling the exterior of the sight cone 10 . Each of the colored rings; color A 13 , color B 14 , color C 15 , color D 16 , color E 17 , being suggestive in number, color and measurement for description purposes only, is a different fluorescent or bright color that could easily be seen from a distance with the naked eye, a scope, or binoculars. Each of the colored ring; color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , are one fifth the length (from the sight cone 10 tip to the sight cone 10 rear opening) of the sight cone 10 , measurements and distribution are suggestive for visual purposes only. The chosen illustration is the description of five (5) colored rings and is strictly for the purpose of describing the function of the colored rings in guiding the hunter to the site where game was standing when shot. This does not, in any way, limit or dictate the number of colored rings on the sight cone 10 .
FIG. 5 is a side and front view of a fallen game locator sight cone 10 .
The side view of the fallen game locator shows each of the chosen fluorescent or brightly colored bands or rings of colors; color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , as one fifth of the sight cone 10 from the large rear opening to the smaller front tip, number of colors and measurements are stated for reference only and do not depict an exacting description.
The front view of the fallen game locator shows the hole for the sighting viewer tube 11 in the center and each of the colored bands of fluorescent or bright color; color A 13 , color B 14 , color C 15 , color D 16 , and color E 17 , as one fifth of the length of the sight tube, colors and measurements stated only for reference and do not limit measurements or colors.
The function of the Fallen Game Locator is to direct the hunter to the exact site where game was when shot. This is accomplished by each of the listed elements in the Fallen Game Locator working in conjunction to point the hunter to the site where game was when shot. After shooting the game, the hunter places or fixes the Fallen Game Locator on to a riser. By looking through the sighting viewer tube 11 from the large opening back plate 12 , the hunter can point the small tip of the Fallen Game Locator sight cone 10 , by looking through the sighting viewer tube 11 from the back plate 12 , directly at the site where game was when shot.
The sight cone 10 , housing the sighting viewer tube 11 , has bands or rings of color; color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , number of colors being suggestive only. When the hunter looks through the sighting viewer tube 11 from the back plate 12 and points the Fallen Game Locator sight tube 10 , to the site where game was when shot, the bands of color: color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , number of listed colors are for reference only, act as a pointing device. When the hunter heads in the general direction where game was when shot, the bands of color; color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed only as a reference, are visible. The hunter can tell which direction to walk or hike towards based upon how the bands of color appear.
Standing in the exact position that the sighting viewer tube 11 is sighted on, the bands of color; color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed for reference only, encircling the sight cone 10 will appear as complete circles of each color; color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed as reference only, in correct proportion to each other, with the look of a circular target. If the hunter is to the right or left of the site, or above or below the site, the hunter will not see a complete circle of each color, but will see a semi-circle of colors; color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed as reference only, in a range of positions from a semi-circle pointing to the right, a semi-circle pointing up, or a semi-circle pointing to the left, or, a semi-circle pointing down. Depending on the direction of ends of the semi-circle, the hunter will know to travel in the direction the ends of the semi-circle of colors; color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed as reference only, are pointing. As the hunter moves in that direction, the position of the ends of the semi-circle of colors, color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed as reference only, will continue to change, continuing to point the hunter in the correct direction until the semi-circle of colors; color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed as reference only, evolves into a complete circle of colors, being: color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed only as reference. Ultimately, upon correct aim of the site cone and viewer tub at the site where game was when shot, the hunter would be able to see light through the sighting viewer tube 11 when standing at the exact site the sighting viewer tube 11 is pointed. At this point, the hunter may start to look for the blood trail, leading him directly to the downed animal, saving hours of searching.
Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention.
Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequently appended claims. | A fallen game locator to aid the hunter in locating the precise location game was when shot. A cylindrical, cone shaped device with unspecified fluorescent or brightly colored series of rings on the exterior, working in conjunction with a target site viewer tube, extending through the small center tip of the cone shaped device, through and beyond the larger opening of the cone shaped device with the back plate in place, and secured to a riser so as to enable the series of colored rings to be seen from multiple locations, at a distance, with the naked eye, a scope, or binoculars, thus economizing the length of time required to find shot game. | Summarize the patent information, clearly outlining the technical challenges and proposed solutions. | [
"CROSS-REFERENCE TO RELATED APPLICATIONS This application is based on Provisional Application Ser.",
"No. 60/961,128, filed Jul. 18, 2007 to Van Lloyd hall, the disclosure of which is incorporated herein by reference and to which priority is claimed.",
"STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not Applicable REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX Not Applicable FIELD OF THE INVENTION The present invention relates to allowing a game hunter to find a downed game, or, at least, the blood trail, and, more particularly, to do so with accuracy, reducing the time searching for downed game.",
"BACKGROUND OF THE INVENTION The hunting party has made all of the necessary preparations and plans.",
"Camping, food, change of clothes, ammunition.",
"You rise early, well before the sun.",
"You eat breakfast while going over the logistics .",
"who will drive the deer (elk, moose, boar, etc.",
") to you who will be sitting on the ridge, waiting to take the shot.",
"With breakfast and plans in place, you leave to carry out this carefully laid plan for the hunt.",
"Everything is going well.",
"You climb to your spotting post and wait.",
"Finally, your target is there.",
"You raise your rifle (or bow), take aim, squeeze off a shot and watch your game falter.",
"This is where the real hunt begins and time is of the essence.",
"You must find the deer, make sure that there is no suffering and save the meat.",
"You leave your shooting post, climb down the hill and go right to the spot you are sure the game was standing when you shot it.",
"You made notes about what to look for.",
"The tall lodge pole pine.",
"The three Aspens on the right of the big rock.",
"You are sure this is the spot.",
"You search and search for a blood tail, any sign.",
"The rest of the hunting party finds you and join in the search.",
"You all spread out.",
"After many crucial hours searching, you have to call it a night.",
"The hunting party returns to camp, worries about the animal being in pain, and all get a restless nights sleep, only to rise in the morning and head back out to search again.",
"The plan is, you will go back to the ridge where you shot from and guide the rest of the hunting party in the search.",
"After another day of hunting, someone finally finds the blood trail.",
"You follow this trail, which leads you several hundred yards to the fallen deer, a healthy four (4) point.",
"Its been a warm Autumn.",
"After this many hours dead, in the sun, the meat is already rotten.",
"The animal is wasted because it took so long to locate, and signs there show a great deal of suffering before the animal finally died.",
"OR;",
"It snows.",
"HARD.",
"All night.",
"You call off the search because there is too much snow to be hiking around looking for a fallen animal.",
"OR;",
"You are so excited to have finally been able to shoot at anything, you take off down the hill before remembering to find your identifying markers and you realized that you have no idea where to begin looking.",
"A search on the internet will take you to any number of articles on just how to track your game, once shot.",
"The suggestions are widely subjective, and center on being able to identify the exact spot your game was standing when it was shot.",
"In many situations, there is simply a lack of distinct identifying markers.",
"BRIEF SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a Fallen Game Locator to aid the hunter in locating the precise location that game was when shot.",
"A cylindrical cone shaped device with fluorescent or brightly colored rings on the outside, a target sighting viewer tube through the center of the cone shaped device and the back plate, and, secured to a riser so as to enable being seen from multiple locations at a distance with the naked eye, a scope or binoculars.",
"An accessory for the hunter, which is light weight, virtually unnoticeable to pack or transport, simple to use and understand, and yet, extremely precise in pointing and guiding the hunter to the exact location game was when shot.",
"By correctly pointing this device to the exact location game was when shot, and then simply following the markers or rings on the exterior of the apparatus as stated in the directions for use, will lead the hunter to the site where game was when shot, thus, enabling the hunter to retrieve the meat expeditiously and reduce spoilage of shot game due to inability to locate game after it has been shot.",
"If made of biodegradable material, minute to no detectable environmental impact occurs with the use of this device.",
"It is therefore an object of the invention to be pointed or aimed directly to the site where game was when it was shot.",
"It is another object of the invention, through the application of exterior markers or rings, to direct the hunter directly to the site where game was when it was shot, according to the appearance of the markers or rings from any given view.",
"It is another object of the invention to reduce the time and effort in finding the site where game was when shot.",
"It is another object of the invention to assist the hunter in the prompt location of shot game, enabling a quick end to the suffering of the shot animal and the safe retrieval of the meat.",
"BRIEF DESCRIPTION OF THE DRAWINGS A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when considered in conjunction with the subsequent, detailed description, in which: FIG. 1 is an exploded view of a fallen game locator;",
"FIG. 2 is a side and front detail view of the sighting viewer tube of the fallen game locator;",
"FIG. 3 is a rear view of the back plate, showing placement of sighting viewer tube in the center of the back plate which is affixed at or in the large opening of the cone shaped object of the fallen game locator;",
"FIG. 4 is a side detail view of the fallen game locator, a cone shaped object, detailing different colored markers or rings, the number and/or color of rings not limited to depiction herein, encircling the exterior of the sight cone;",
"and, FIG. 5 is a side and front view of a fallen game locator sight cone showing an example of detail relating to the colored rings or markers on the exterior of said cone.",
"For purposes of clarity and brevity, like elements and components will bear the same designations and numbering throughout the FIGURES.",
"Throughout this Non-provisional patent application, the number of rings and the colors stated are suggestive in nature and used herein for suggested and visual purposes and in no way depict, or limit any set number of markers or rings nor any set measurement of any part of the subject of the invention, or, any set use of colors as the exterior markers or rings.",
"DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is an exploded view of all essential elements of the fallen game locator.",
"This consists of the sight cone 10 encircled with one (1) section each, of five (5) chosen fluorescent or very bright colors;",
"color A 13 , color B 14 , color C 15 , color D 16 , and color E 17 , as well as the sighting viewer tube 11 and the back plate 12 .",
"The sight cone 10 should be of ample size in length and diameter to be seen from a distance with the naked eye, a scope, or binoculars.",
"The sight cone 10 is placed or fastened on a riser or surface that will allow it to be seen from a distance with the naked eye, a scope, or binoculars.",
"The sight cone 10 is divided evenly five (5) times, stated only to provide a visual reference and not to limit the invention in any way, from the front tip to the rear opening with colored rings.",
"Each of the five (5) colored rings;",
"color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , number of rings being used for example herein, is a different fluorescent or bright color that would be easily seen from a distance with the naked eye, a scope, or binoculars.",
"The sight cone 10 is capped off at the large opening with the back plate 12 .",
"The back plate 12 has a hole in the center, similar in size to the exterior diameter of the sighting viewer tube 11 .",
"The sighting viewer tube 11 is placed in and through the sight cone 10 from the front small tip to and through the back plate 12 , being inserted in the hole in the exact center of the back plate 12 .",
"FIG. 2 is a side and front view of a sighting viewer tube 11 .",
"The sighting viewer tube 11 is inserted in and through the sight cone 10 , extending from beyond the back plate 12 to the front tip of the sight cone 10 .",
"The sighting viewer tube 11 is small in diameter, but large enough that a person with normal eyesight can look through it to a point a distance away.",
"The exterior dimension of the sighting viewer tube 11 is similar in size to the opening in the back plate 12 and the front tip of the sight cone 10 .",
"FIG. 3 is a back plate 12 detail of a fallen game locator showing placement of sighting viewer tube 11 in the center of the back plate 12 .",
"The exterior dimension of the back plate 12 is slightly less than the interior dimension of the sight cone 10 .",
"The hole in the center of the back plate 12 is similar in dimension as the exterior dimension of the sighting viewer tube 11 .",
"FIG. 4 is a side detail view of five (5) colored rings, which number and color of rings and suggested only for purpose of reference in this application, encircling the exterior of the sight cone 10 .",
"Each of the colored rings;",
"color A 13 , color B 14 , color C 15 , color D 16 , color E 17 , being suggestive in number, color and measurement for description purposes only, is a different fluorescent or bright color that could easily be seen from a distance with the naked eye, a scope, or binoculars.",
"Each of the colored ring;",
"color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , are one fifth the length (from the sight cone 10 tip to the sight cone 10 rear opening) of the sight cone 10 , measurements and distribution are suggestive for visual purposes only.",
"The chosen illustration is the description of five (5) colored rings and is strictly for the purpose of describing the function of the colored rings in guiding the hunter to the site where game was standing when shot.",
"This does not, in any way, limit or dictate the number of colored rings on the sight cone 10 .",
"FIG. 5 is a side and front view of a fallen game locator sight cone 10 .",
"The side view of the fallen game locator shows each of the chosen fluorescent or brightly colored bands or rings of colors;",
"color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , as one fifth of the sight cone 10 from the large rear opening to the smaller front tip, number of colors and measurements are stated for reference only and do not depict an exacting description.",
"The front view of the fallen game locator shows the hole for the sighting viewer tube 11 in the center and each of the colored bands of fluorescent or bright color;",
"color A 13 , color B 14 , color C 15 , color D 16 , and color E 17 , as one fifth of the length of the sight tube, colors and measurements stated only for reference and do not limit measurements or colors.",
"The function of the Fallen Game Locator is to direct the hunter to the exact site where game was when shot.",
"This is accomplished by each of the listed elements in the Fallen Game Locator working in conjunction to point the hunter to the site where game was when shot.",
"After shooting the game, the hunter places or fixes the Fallen Game Locator on to a riser.",
"By looking through the sighting viewer tube 11 from the large opening back plate 12 , the hunter can point the small tip of the Fallen Game Locator sight cone 10 , by looking through the sighting viewer tube 11 from the back plate 12 , directly at the site where game was when shot.",
"The sight cone 10 , housing the sighting viewer tube 11 , has bands or rings of color;",
"color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , number of colors being suggestive only.",
"When the hunter looks through the sighting viewer tube 11 from the back plate 12 and points the Fallen Game Locator sight tube 10 , to the site where game was when shot, the bands of color: color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , number of listed colors are for reference only, act as a pointing device.",
"When the hunter heads in the general direction where game was when shot, the bands of color;",
"color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed only as a reference, are visible.",
"The hunter can tell which direction to walk or hike towards based upon how the bands of color appear.",
"Standing in the exact position that the sighting viewer tube 11 is sighted on, the bands of color;",
"color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed for reference only, encircling the sight cone 10 will appear as complete circles of each color;",
"color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed as reference only, in correct proportion to each other, with the look of a circular target.",
"If the hunter is to the right or left of the site, or above or below the site, the hunter will not see a complete circle of each color, but will see a semi-circle of colors;",
"color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed as reference only, in a range of positions from a semi-circle pointing to the right, a semi-circle pointing up, or a semi-circle pointing to the left, or, a semi-circle pointing down.",
"Depending on the direction of ends of the semi-circle, the hunter will know to travel in the direction the ends of the semi-circle of colors;",
"color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed as reference only, are pointing.",
"As the hunter moves in that direction, the position of the ends of the semi-circle of colors, color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed as reference only, will continue to change, continuing to point the hunter in the correct direction until the semi-circle of colors;",
"color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed as reference only, evolves into a complete circle of colors, being: color A 13 , color B 14 , color C 15 , color D 16 and color E 17 , listed only as reference.",
"Ultimately, upon correct aim of the site cone and viewer tub at the site where game was when shot, the hunter would be able to see light through the sighting viewer tube 11 when standing at the exact site the sighting viewer tube 11 is pointed.",
"At this point, the hunter may start to look for the blood trail, leading him directly to the downed animal, saving hours of searching.",
"Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention.",
"Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequently appended claims."
] |
BACKGROUND
The method and system disclosed herein, in general, relates to information analysis and specifically relates to a system and method for presenting the information of interest of an end user in the preferred writing style of the end user.
The world-wide web contains billions of web pages of information. In addition, a large amount of information is also stored on enterprise systems, public and commercial databases, etc. As the number of information sources increase, identifying or finding the information of interest is requiring more time and becoming increasingly difficult for a user. There is a market need to find and present the information of interest to a user from one or more of the aforementioned sources of information.
In order to provide to the user his/her information of interest, culled from a body of source information in an acceptable amount of time, co-pending patent application titled “Capturing reading style”, Patent application No. 1819/CHE/2005 filed in India on Dec. 13, 2005 illustrates a method of capturing the reading style of a user, wherein the reading style is a set of one or more declared patterns. A declared pattern contains a set of source components. The user declares patterns from source components. There are different kinds of source components such as sentences, paragraphs, etc. Co-pending patent application “Pattern Generation”, generates equivalent patterns that includes all the manifestations of the declared pattern of an end user's reading style, thereby providing the ability to comprehensively and accurately determine the information of interest from an information source.
When the information of interest has been determined using the method and system disclosed in patent application titled “Capturing Reading Styles”, the information of interest needs to be presented to the end user in the user's preferred style of presentation. There is an unmet market need to present the above information interest in the preferred presentation style of the end user.
SUMMARY OF THE INVENTION
The method and system disclosed herein presents the information of interest in the preferred presentation style of the end user. The presentation style comprises the writing style and the rendering style.
The method and system disclosed herein constructs reports from an information of interest. The writing style of a user is first generated. The writing style comprises a prose style and a report pattern style. The report is rendered to the user in the user's preferred rendering style. The writing style and the rendering style are applied to the information of interest to construct said reports. The information of interest was generated as a result of applying the reading style of a user to a plurality of information sources. The formal style is applicable in a formal business environment, and is inclusive of, but not restricted to business e-mail, business plans, presentations. The informal style is applicable for communication with friends and casual business settings, and is inclusive of but not restricted to e-mail and general informal correspondences.
The prose style of a user is derived from preferred equivalent name sets and preferred equivalent pattern specification sets. The equivalent name sets and the equivalent pattern sets are derived from the reading process. The preferred equivalent name set entries are derived from the equivalent name sets for the given context. Similarly, the preferred pattern specification set is derived from the equivalent pattern specification set for the given context.
The preferred pattern set further comprises embellishments that are words or phrase that the author characteristically uses to describe a subject, object or verb. The embellishments are selected from the equivalent name sets depending on the context of the information of interest.
The constructed report contains report sections that are arranged by a user specified method of sequencing the contents of the report. The sequence can either be fixed or computed. In a fixed sequence, either a specific hierarchy or an ordered list of semantic items is defined explicitly. In a computed sequence, a user defined method is applied to determine the sequence of semantic items. During the creation of a computed sequence by the user, the user provides a specific method for determining the sequence of the contents of the report. This method is typically based on the number, kinds, and values of the specific information of interest found, relative to their position in the hierarchy of semantic items.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings exemplary constructions of the invention; however, the invention is not limited to the specific methods and instrumentalities disclosed.
FIG. 1 illustrates the structure of a report.
FIG. 2 illustrates an overview of the method for constructing reports.
FIG. 3 illustrates the creation and application of the report pattern.
FIG. 4 illustrates the creation and application of the prose style.
FIG. 5 illustrates the creation and application of the report rendering style.
DETAILED DESCRIPTION OF THE INVENTION
The definitions of the technical terms used herein are provided below.
Declared pattern (DP): A pattern that matches words found in a sentence. Document: A document is an electronic file, comprising one or more of the following: text, pictures, audio and video. Embellishment patterns: An embellishments pattern prescribes a word or phrase that accompanies the subject, object or verb. Each writer has a specific embellishment pattern set that they typically use while writing. Equivalent pattern specification (EPS) sets: Sets of equivalent pattern specifications that for a given language represent different ways of saying the same thing. Equivalent name set (ENS): Set of words that have the same meaning. Information of interest: The relevant information desired in the language-specific LS information source. Information source: Information, for example, one or more source documents to be read. Private ontology: Comprises semantic items and their inter-relationships. The private ontology is structured specifically to the view of a user. A private ontology comprises definitions of semantic items in a domain of interest of the user and defines the relationship between the semantic items. Prose style: A prose style is a specific set of language patterns with a specific choice of vocabulary. The vocabulary includes equivalent name sets and embellishments Reader module: A system and process for scanning the LS information source to produce the information of interest (IOI) by using the generated LS reading pattern recognition rules (rules code), LS reading syntactic context processing rules (code), and LS ENS. Reading pattern generator: A method and system that generates a set of language-specific world view-specific sentence patterns that expand upon the declared sentence pattern, thereby recognizing a larger number of matching word patterns in an information source. Reading style: A set of one or more declared patterns. A declared pattern contains a set of source components. A pattern identifies a specific semantic item. The user declares patterns from source components and thereby captures the reading style. There are different kinds of source components such as sentences, paragraphs, etc. Reading plan: The reading plan is a set of steps defined by the user that identifies and controls the evaluation sequence of a source document. The reading plan allows for efficient processing of source documents by reducing the amount of data to be evaluated. Report pattern: A report pattern is composed of a plurality of report sections that are arranged in a predetermined information sequence. Semantic item: A semantic item is one of the following: a thing, a type of thing, a characteristic, or a relationship between things and types of things. Sentence patterns: Generated patterns that are able to recognize a large number of matching word patterns found in language specific information sources. Worldview: The worldview of the user comprises the reading style, reading plan and private ontology of the user. It reflects the logic and structure with which a user comprehends a document. World view acquisition (WVA): A process for interacting with a user to produce declared sentence patterns, reading plans, and private ontologies.
FIG. 1 illustrates the structure of a report. The constructed report 101 displays the desired information of the user in the user's preferred presentation structure. The user's preferred writing style 102 and rendering style 103 govern the preferred presentation structure. The report pattern 104 and prose style 105 define the user's preferred writing style 102 . The user may have a plurality of preferred writing styles 102 . For example, consider the case of a user who is a financial stockbroker by profession and a traveler by hobby. The user may desire to view economic information about India in his or her preferred writing style, for example, in the typical structure of a country economic report issued by Moody's. Whereas, the same user may desire to read travel information on India in a manner presented by the authors of the travelogue “Lonely Planet”.
FIG. 2 illustrates an overview of the method of constructing reports. The details of the reading process are described in detail in the co-pending patent applications “Capturing reading style” and “Patten generation”. However, in brief, the reading style 211 and the ontology 216 of the user are captured using the method described in the above two patent applications. The reading style 211 and the ontology 216 , along with equivalent pattern set (EPS) 203 and equivalent name sets (ENS) 202 , are fed into the reading style capture 213 to generate users reader data 214 . The reader 215 applies the reader data 214 to the writing style training documents 204 to generate the information of interest (IOI) 207 of the user.
The equivalent pattern set (EPS) 203 , equivalent name sets (ENS) 202 , the writing style training documents 204 along with the information of interest 207 are fed into the writing style capture 208 process to generate the user's writing style data 205 . The user's writing style data 205 comprises the users preferred prose style 105 and report pattern 104 . The user's writing style data 205 is applied 209 in conjunction with the report rendering style 206 to the information of interest 207 to construct the report.
The writing style 101 is perfected iteratively using training documents 204 . Writing style training documents 204 are referenced by the IOI 207 . For example, consider the annual reports of CocaCola Inc. Assume that CocaCola Inc. uses a similar annual report format every year. Consider the case of an annual report for CocaCola Inc. constructed for the year 2005. This report is constructed using raw data and the writing and rendering style derived from the annual reports of the previous years that were used as training documents. This constructed annual report for 2005 is then compared with the actual annual report of 2005 and manual or automated corrections to the writing and rendering style are appropriately made.
FIG. 3 illustrates the creation and application of a report pattern. A report pattern 104 is composed of a plurality of report sections 303 that are arranged in a predetermined information sequence 304 . The report section 303 may in turn, comprise one or more report sections 303 . Each report section 303 comprises one or more section components 308 . Each section component 308 may optionally contain a section header 306 , and optionally comprises chart or graph descriptors 310 and paragraph descriptors 311 . The information sequencing 304 , i.e. the sequence of the sections in the report may either be a fixed sequence 307 or a computed sequence 309 . The fixed sequencing 307 does not depend on the information of interest 207 .
The fixed sequence 307 is derived based on semantic items 305 in the ontology. In the case of the fixed sequence 307 , either the traversal can be based on hierarchy traversal 313 or the traversal can be based on a defined enumeration of semantic items 312 . There are various algorithms that can be used to traverse a graph, for example, a set of sibling nodes can be traversed, followed by traversing an adjoining set of sibling node; or the graph can be traversed by traversing from a node to its daughter node and traversing further down the graph. In the case of the fixed sequence 307 , the method of sequencing the traversal is based on the private ontology of the user 216 and not on the information of interest 207 . For example, consider the information of interest to be the accomplishments of the year for ABC Truck Company Ltd. The accomplishments will include the accomplishments of the truck division, engine division and engine parts division. The aforementioned three divisions presented in a sequence represent a fixed sequence. In the user's ontology, the three divisions are described in a certain fixed hierarchy, i.e., the truck division is first, followed by the engine division, and finally followed by the spare parts division. Hence, the hierarchy of these divisions is traversed in a fixed manner. Even if there is no information available on the spare parts division, the section header would still be presented, without any underlying content.
Consider the following example of a hierarchy traversal. Consider a monthly report with a list of projects, wherein the projects are of different types such as external client projects, internal client projects, government projects etc. The graph traversal algorithm that depends on the private ontology of the user will involve traversing to a project, then traversing to that project's children and then traversing further down to the children's children. An example of a child of an external project is the logistics activity, and an example of the child's child is the type of vehicle used, such as heavy trucks used in the logistics activity. In a sequence graph traversal, the information of interest is reorganized into lists based on chronology, such as oldest to newest, or based on complexity, for example from the simplest concept to the most complex concept etc.
There could be multiplicities of hierarchies. For example, the accomplishments could be arranged by the accomplishments of heavy trucks, light trucks, passenger trucks etc. In the alternative, the accomplishments could also be arranged on the basis of geographical regions, such as the accomplishments of the North American division, South American Division, Asian Division etc. However, in the case of the fixed sequence, for a single hierarchy under consideration, the hierarchy can only be traversed in one path.
In the case of the computed sequence 309 , the user states their sequence requirements in a customized fashion not necessarily following any hierarchy. For example, the user might require sales information first presented by quarter and then by financial year, followed by calendar year sales. The computed sequence 309 follows no fixed logic; it reflects the user's contextual requirements. For example, if a user requests information on Uganda, the user may prefer to chronologically have the information presented in the order of the latest information listed first. The computed sequence 309 is typically used in scenarios where the user is not exactly sure of what he or she wants, and the user discovers their needs as they are presented with new information.
The computed sequence 309 is captured based on the users observation of the information of interest (IOI) 207 , and is derived based on discrete semantic items or on a sequence graph traversal 315 . The sequence graph traversal 315 is based on traversing a graph wherein the user computes the nodes in the graph. In the case of discrete semantic items 314 traversal , the algorithm that operates on the IOI then selects the next IOI. Each concept has a defined level of precedence. The algorithm operates on the basis of the precedence levels or on the basis of complexity 318 . The algorithm selects one semantic item from one run of an IOI 207 .
The semantic items 305 within the discrete semantic items graph are derived from the semantic items 305 within the information of interest 207 of the user. The sequence graph traversal 315 is based on complexity 318 , chronology 319 or other 320 types of traversal paths.
FIG. 4 illustrates the creation and application of prose style. Prose is a specific language pattern with a specific choice of vocabulary. The specific language pattern is preferred equivalent pattern specifications sets 404 and preferred ENS entry sets 403 . A declared pattern is captured during the reading process and the equivalent pattern specification 407 and the equivalent pattern specification set 406 are identified for this declared pattern. A preferred pattern specification 405 is selected from the equivalent pattern specification 407 , and multiple such selections are populated into a preferred equivalent specification set 405 . A set of these selections includes multiple representations of a singular meaning.
For a given language, each semantic items 305 maps to a single ENS 202 . The equivalent name set 202 contains multiple items, i.e. multiple entries. A preferred ENS entry 403 is selected from the ENS entries 401 . Multiple such selections are populated into a preferred ENS entry set 403 .
The vocabulary is derived from the equivalent name sets (ENS) 202 , the ENS 202 is captured during the reading process. For the semantic items 305 in the information of interest 206 , corresponding ENS entries 401 are mapped and identified.
An embellishments pattern 409 is a word or phrase that accompany the subject, object or verb. Each writer has a specific embellishment pattern 409 that they typically use while writing. The embellishments are captured during the reading process. The embellishments are a subset of the ENS 202 . Natural language processing is used to determine the type of embellishment, such as if the embellishment is an adjective or adverb etc. If the embellishment uses a specific ENS 202 , then that specific ENS 202 is recorded. The condition of application 408 is the environment or conditions under which the embellishment is applied. Depending on the condition of application 408 , the appropriate embellishment is identified. Also, depending on the usage context, words or phrases can be inserted 410 in the embellishment pattern 409 , and other modifications 411 are performed for the identified embellishment pattern. For example, if a user would like the subject or the information of interest presented to him or her in the writing style of the novelist P. G. Wodehouse, the subject “snore” would be embellished with the words “snore that sounds like a fog horn”.
FIG. 5 illustrates the method and system used for rendering the report to the user. FIG. 5 is exemplary and not restrictive; in addition to the formal and informal style there are multiple other styles of presenting the report. The report rendering style 206 is classified in formal style 501 and informal style 502 . The formal style 501 is applicable in a formal business environment, and is inclusive of, but not restricted to business e-mail 504 , business plans 503 , presentations 507 (such as Microsoft Powerpoint® of Microsoft Inc.), etc. The informal style 502 is applicable for communication with friends and casual business settings, and is inclusive of but not restricted to e-mail 505 , articles 506 etc.
Consider an example of a formal report rendering style for an e-mail sent by a Joe Smith, Patent Attorney. The formal structure would include a confidentiality statement inserted at the end of the e-mail. The recipient of the e-mail would be addressed by “Mr” or “Ms.” Followed by the last name, and then followed by “:”. This would reflect Joe Smith's personal style of writing business e-mails.
Consider an example of an informal report rendering style for e-mail sent by Joe Smith to his friend Adam Wood. In this example, the recipient of the e-mail, i.e. Adam Wood would be addressed by “adam”, followed by “,”. Sentences in the body of the e-mail do not start with a capital letter. This would reflect Joe Smith's personal style of personal writing e-mails.
An example of the structure of a report and writing style is briefly outlined below. For a marketing monthly summary report provided for the marketing manager of a company, the structure of the report could comprise a first section on the new clients, a second section on new product introductions, followed by a third section on sales targets. The writing style, renders the report containing these three sections displayed in a cascaded form, surrounded by market share pie charts, and the prose with headings such as “target market”, “competitors”, etc.
The foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting the present invention. While the invention has been described with reference to various embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitations. Further, although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein; rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. Those skilled in the art, having the benefit of the teachings of this specification, may effect numerous modifications thereto and changes may be made without departing from the scope and spirit of the invention in its aspects. | A computer implemented method and system is disclosed herein for constructing reports, comprising the steps of providing the information of interest of a user and generating the writing style of a user. The step of generating the writing style further comprises the steps of generating a prose style and report pattern style, generating the rendering style of a user, and applying the writing style to the information of interest to provide the constructed report. The method of deriving the prose style comprises the steps of deriving preferred equivalent name set entry sets, preferred equivalent pattern specification sets; and embellishment patterns. | Condense the core contents of the given document. | [
"BACKGROUND The method and system disclosed herein, in general, relates to information analysis and specifically relates to a system and method for presenting the information of interest of an end user in the preferred writing style of the end user.",
"The world-wide web contains billions of web pages of information.",
"In addition, a large amount of information is also stored on enterprise systems, public and commercial databases, etc.",
"As the number of information sources increase, identifying or finding the information of interest is requiring more time and becoming increasingly difficult for a user.",
"There is a market need to find and present the information of interest to a user from one or more of the aforementioned sources of information.",
"In order to provide to the user his/her information of interest, culled from a body of source information in an acceptable amount of time, co-pending patent application titled “Capturing reading style”, Patent application No. 1819/CHE/2005 filed in India on Dec. 13, 2005 illustrates a method of capturing the reading style of a user, wherein the reading style is a set of one or more declared patterns.",
"A declared pattern contains a set of source components.",
"The user declares patterns from source components.",
"There are different kinds of source components such as sentences, paragraphs, etc.",
"Co-pending patent application “Pattern Generation”, generates equivalent patterns that includes all the manifestations of the declared pattern of an end user's reading style, thereby providing the ability to comprehensively and accurately determine the information of interest from an information source.",
"When the information of interest has been determined using the method and system disclosed in patent application titled “Capturing Reading Styles”, the information of interest needs to be presented to the end user in the user's preferred style of presentation.",
"There is an unmet market need to present the above information interest in the preferred presentation style of the end user.",
"SUMMARY OF THE INVENTION The method and system disclosed herein presents the information of interest in the preferred presentation style of the end user.",
"The presentation style comprises the writing style and the rendering style.",
"The method and system disclosed herein constructs reports from an information of interest.",
"The writing style of a user is first generated.",
"The writing style comprises a prose style and a report pattern style.",
"The report is rendered to the user in the user's preferred rendering style.",
"The writing style and the rendering style are applied to the information of interest to construct said reports.",
"The information of interest was generated as a result of applying the reading style of a user to a plurality of information sources.",
"The formal style is applicable in a formal business environment, and is inclusive of, but not restricted to business e-mail, business plans, presentations.",
"The informal style is applicable for communication with friends and casual business settings, and is inclusive of but not restricted to e-mail and general informal correspondences.",
"The prose style of a user is derived from preferred equivalent name sets and preferred equivalent pattern specification sets.",
"The equivalent name sets and the equivalent pattern sets are derived from the reading process.",
"The preferred equivalent name set entries are derived from the equivalent name sets for the given context.",
"Similarly, the preferred pattern specification set is derived from the equivalent pattern specification set for the given context.",
"The preferred pattern set further comprises embellishments that are words or phrase that the author characteristically uses to describe a subject, object or verb.",
"The embellishments are selected from the equivalent name sets depending on the context of the information of interest.",
"The constructed report contains report sections that are arranged by a user specified method of sequencing the contents of the report.",
"The sequence can either be fixed or computed.",
"In a fixed sequence, either a specific hierarchy or an ordered list of semantic items is defined explicitly.",
"In a computed sequence, a user defined method is applied to determine the sequence of semantic items.",
"During the creation of a computed sequence by the user, the user provides a specific method for determining the sequence of the contents of the report.",
"This method is typically based on the number, kinds, and values of the specific information of interest found, relative to their position in the hierarchy of semantic items.",
"BRIEF DESCRIPTION OF THE DRAWINGS The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawings.",
"For the purpose of illustrating the invention, there is shown in the drawings exemplary constructions of the invention;",
"however, the invention is not limited to the specific methods and instrumentalities disclosed.",
"FIG. 1 illustrates the structure of a report.",
"FIG. 2 illustrates an overview of the method for constructing reports.",
"FIG. 3 illustrates the creation and application of the report pattern.",
"FIG. 4 illustrates the creation and application of the prose style.",
"FIG. 5 illustrates the creation and application of the report rendering style.",
"DETAILED DESCRIPTION OF THE INVENTION The definitions of the technical terms used herein are provided below.",
"Declared pattern (DP): A pattern that matches words found in a sentence.",
"Document: A document is an electronic file, comprising one or more of the following: text, pictures, audio and video.",
"Embellishment patterns: An embellishments pattern prescribes a word or phrase that accompanies the subject, object or verb.",
"Each writer has a specific embellishment pattern set that they typically use while writing.",
"Equivalent pattern specification (EPS) sets: Sets of equivalent pattern specifications that for a given language represent different ways of saying the same thing.",
"Equivalent name set (ENS): Set of words that have the same meaning.",
"Information of interest: The relevant information desired in the language-specific LS information source.",
"Information source: Information, for example, one or more source documents to be read.",
"Private ontology: Comprises semantic items and their inter-relationships.",
"The private ontology is structured specifically to the view of a user.",
"A private ontology comprises definitions of semantic items in a domain of interest of the user and defines the relationship between the semantic items.",
"Prose style: A prose style is a specific set of language patterns with a specific choice of vocabulary.",
"The vocabulary includes equivalent name sets and embellishments Reader module: A system and process for scanning the LS information source to produce the information of interest (IOI) by using the generated LS reading pattern recognition rules (rules code), LS reading syntactic context processing rules (code), and LS ENS.",
"Reading pattern generator: A method and system that generates a set of language-specific world view-specific sentence patterns that expand upon the declared sentence pattern, thereby recognizing a larger number of matching word patterns in an information source.",
"Reading style: A set of one or more declared patterns.",
"A declared pattern contains a set of source components.",
"A pattern identifies a specific semantic item.",
"The user declares patterns from source components and thereby captures the reading style.",
"There are different kinds of source components such as sentences, paragraphs, etc.",
"Reading plan: The reading plan is a set of steps defined by the user that identifies and controls the evaluation sequence of a source document.",
"The reading plan allows for efficient processing of source documents by reducing the amount of data to be evaluated.",
"Report pattern: A report pattern is composed of a plurality of report sections that are arranged in a predetermined information sequence.",
"Semantic item: A semantic item is one of the following: a thing, a type of thing, a characteristic, or a relationship between things and types of things.",
"Sentence patterns: Generated patterns that are able to recognize a large number of matching word patterns found in language specific information sources.",
"Worldview: The worldview of the user comprises the reading style, reading plan and private ontology of the user.",
"It reflects the logic and structure with which a user comprehends a document.",
"World view acquisition (WVA): A process for interacting with a user to produce declared sentence patterns, reading plans, and private ontologies.",
"FIG. 1 illustrates the structure of a report.",
"The constructed report 101 displays the desired information of the user in the user's preferred presentation structure.",
"The user's preferred writing style 102 and rendering style 103 govern the preferred presentation structure.",
"The report pattern 104 and prose style 105 define the user's preferred writing style 102 .",
"The user may have a plurality of preferred writing styles 102 .",
"For example, consider the case of a user who is a financial stockbroker by profession and a traveler by hobby.",
"The user may desire to view economic information about India in his or her preferred writing style, for example, in the typical structure of a country economic report issued by Moody's.",
"Whereas, the same user may desire to read travel information on India in a manner presented by the authors of the travelogue “Lonely Planet.”",
"FIG. 2 illustrates an overview of the method of constructing reports.",
"The details of the reading process are described in detail in the co-pending patent applications “Capturing reading style”",
"and “Patten generation.”",
"However, in brief, the reading style 211 and the ontology 216 of the user are captured using the method described in the above two patent applications.",
"The reading style 211 and the ontology 216 , along with equivalent pattern set (EPS) 203 and equivalent name sets (ENS) 202 , are fed into the reading style capture 213 to generate users reader data 214 .",
"The reader 215 applies the reader data 214 to the writing style training documents 204 to generate the information of interest (IOI) 207 of the user.",
"The equivalent pattern set (EPS) 203 , equivalent name sets (ENS) 202 , the writing style training documents 204 along with the information of interest 207 are fed into the writing style capture 208 process to generate the user's writing style data 205 .",
"The user's writing style data 205 comprises the users preferred prose style 105 and report pattern 104 .",
"The user's writing style data 205 is applied 209 in conjunction with the report rendering style 206 to the information of interest 207 to construct the report.",
"The writing style 101 is perfected iteratively using training documents 204 .",
"Writing style training documents 204 are referenced by the IOI 207 .",
"For example, consider the annual reports of CocaCola Inc. Assume that CocaCola Inc. uses a similar annual report format every year.",
"Consider the case of an annual report for CocaCola Inc. constructed for the year 2005.",
"This report is constructed using raw data and the writing and rendering style derived from the annual reports of the previous years that were used as training documents.",
"This constructed annual report for 2005 is then compared with the actual annual report of 2005 and manual or automated corrections to the writing and rendering style are appropriately made.",
"FIG. 3 illustrates the creation and application of a report pattern.",
"A report pattern 104 is composed of a plurality of report sections 303 that are arranged in a predetermined information sequence 304 .",
"The report section 303 may in turn, comprise one or more report sections 303 .",
"Each report section 303 comprises one or more section components 308 .",
"Each section component 308 may optionally contain a section header 306 , and optionally comprises chart or graph descriptors 310 and paragraph descriptors 311 .",
"The information sequencing 304 , i.e. the sequence of the sections in the report may either be a fixed sequence 307 or a computed sequence 309 .",
"The fixed sequencing 307 does not depend on the information of interest 207 .",
"The fixed sequence 307 is derived based on semantic items 305 in the ontology.",
"In the case of the fixed sequence 307 , either the traversal can be based on hierarchy traversal 313 or the traversal can be based on a defined enumeration of semantic items 312 .",
"There are various algorithms that can be used to traverse a graph, for example, a set of sibling nodes can be traversed, followed by traversing an adjoining set of sibling node;",
"or the graph can be traversed by traversing from a node to its daughter node and traversing further down the graph.",
"In the case of the fixed sequence 307 , the method of sequencing the traversal is based on the private ontology of the user 216 and not on the information of interest 207 .",
"For example, consider the information of interest to be the accomplishments of the year for ABC Truck Company Ltd. The accomplishments will include the accomplishments of the truck division, engine division and engine parts division.",
"The aforementioned three divisions presented in a sequence represent a fixed sequence.",
"In the user's ontology, the three divisions are described in a certain fixed hierarchy, i.e., the truck division is first, followed by the engine division, and finally followed by the spare parts division.",
"Hence, the hierarchy of these divisions is traversed in a fixed manner.",
"Even if there is no information available on the spare parts division, the section header would still be presented, without any underlying content.",
"Consider the following example of a hierarchy traversal.",
"Consider a monthly report with a list of projects, wherein the projects are of different types such as external client projects, internal client projects, government projects etc.",
"The graph traversal algorithm that depends on the private ontology of the user will involve traversing to a project, then traversing to that project's children and then traversing further down to the children's children.",
"An example of a child of an external project is the logistics activity, and an example of the child's child is the type of vehicle used, such as heavy trucks used in the logistics activity.",
"In a sequence graph traversal, the information of interest is reorganized into lists based on chronology, such as oldest to newest, or based on complexity, for example from the simplest concept to the most complex concept etc.",
"There could be multiplicities of hierarchies.",
"For example, the accomplishments could be arranged by the accomplishments of heavy trucks, light trucks, passenger trucks etc.",
"In the alternative, the accomplishments could also be arranged on the basis of geographical regions, such as the accomplishments of the North American division, South American Division, Asian Division etc.",
"However, in the case of the fixed sequence, for a single hierarchy under consideration, the hierarchy can only be traversed in one path.",
"In the case of the computed sequence 309 , the user states their sequence requirements in a customized fashion not necessarily following any hierarchy.",
"For example, the user might require sales information first presented by quarter and then by financial year, followed by calendar year sales.",
"The computed sequence 309 follows no fixed logic;",
"it reflects the user's contextual requirements.",
"For example, if a user requests information on Uganda, the user may prefer to chronologically have the information presented in the order of the latest information listed first.",
"The computed sequence 309 is typically used in scenarios where the user is not exactly sure of what he or she wants, and the user discovers their needs as they are presented with new information.",
"The computed sequence 309 is captured based on the users observation of the information of interest (IOI) 207 , and is derived based on discrete semantic items or on a sequence graph traversal 315 .",
"The sequence graph traversal 315 is based on traversing a graph wherein the user computes the nodes in the graph.",
"In the case of discrete semantic items 314 traversal , the algorithm that operates on the IOI then selects the next IOI.",
"Each concept has a defined level of precedence.",
"The algorithm operates on the basis of the precedence levels or on the basis of complexity 318 .",
"The algorithm selects one semantic item from one run of an IOI 207 .",
"The semantic items 305 within the discrete semantic items graph are derived from the semantic items 305 within the information of interest 207 of the user.",
"The sequence graph traversal 315 is based on complexity 318 , chronology 319 or other 320 types of traversal paths.",
"FIG. 4 illustrates the creation and application of prose style.",
"Prose is a specific language pattern with a specific choice of vocabulary.",
"The specific language pattern is preferred equivalent pattern specifications sets 404 and preferred ENS entry sets 403 .",
"A declared pattern is captured during the reading process and the equivalent pattern specification 407 and the equivalent pattern specification set 406 are identified for this declared pattern.",
"A preferred pattern specification 405 is selected from the equivalent pattern specification 407 , and multiple such selections are populated into a preferred equivalent specification set 405 .",
"A set of these selections includes multiple representations of a singular meaning.",
"For a given language, each semantic items 305 maps to a single ENS 202 .",
"The equivalent name set 202 contains multiple items, i.e. multiple entries.",
"A preferred ENS entry 403 is selected from the ENS entries 401 .",
"Multiple such selections are populated into a preferred ENS entry set 403 .",
"The vocabulary is derived from the equivalent name sets (ENS) 202 , the ENS 202 is captured during the reading process.",
"For the semantic items 305 in the information of interest 206 , corresponding ENS entries 401 are mapped and identified.",
"An embellishments pattern 409 is a word or phrase that accompany the subject, object or verb.",
"Each writer has a specific embellishment pattern 409 that they typically use while writing.",
"The embellishments are captured during the reading process.",
"The embellishments are a subset of the ENS 202 .",
"Natural language processing is used to determine the type of embellishment, such as if the embellishment is an adjective or adverb etc.",
"If the embellishment uses a specific ENS 202 , then that specific ENS 202 is recorded.",
"The condition of application 408 is the environment or conditions under which the embellishment is applied.",
"Depending on the condition of application 408 , the appropriate embellishment is identified.",
"Also, depending on the usage context, words or phrases can be inserted 410 in the embellishment pattern 409 , and other modifications 411 are performed for the identified embellishment pattern.",
"For example, if a user would like the subject or the information of interest presented to him or her in the writing style of the novelist P. G. Wodehouse, the subject “snore”",
"would be embellished with the words “snore that sounds like a fog horn.”",
"FIG. 5 illustrates the method and system used for rendering the report to the user.",
"FIG. 5 is exemplary and not restrictive;",
"in addition to the formal and informal style there are multiple other styles of presenting the report.",
"The report rendering style 206 is classified in formal style 501 and informal style 502 .",
"The formal style 501 is applicable in a formal business environment, and is inclusive of, but not restricted to business e-mail 504 , business plans 503 , presentations 507 (such as Microsoft Powerpoint® of Microsoft Inc.), etc.",
"The informal style 502 is applicable for communication with friends and casual business settings, and is inclusive of but not restricted to e-mail 505 , articles 506 etc.",
"Consider an example of a formal report rendering style for an e-mail sent by a Joe Smith, Patent Attorney.",
"The formal structure would include a confidentiality statement inserted at the end of the e-mail.",
"The recipient of the e-mail would be addressed by “Mr”",
"or “Ms.”",
"Followed by the last name, and then followed by “:.”",
"This would reflect Joe Smith's personal style of writing business e-mails.",
"Consider an example of an informal report rendering style for e-mail sent by Joe Smith to his friend Adam Wood.",
"In this example, the recipient of the e-mail, i.e. Adam Wood would be addressed by “adam”, followed by “,”.",
"Sentences in the body of the e-mail do not start with a capital letter.",
"This would reflect Joe Smith's personal style of personal writing e-mails.",
"An example of the structure of a report and writing style is briefly outlined below.",
"For a marketing monthly summary report provided for the marketing manager of a company, the structure of the report could comprise a first section on the new clients, a second section on new product introductions, followed by a third section on sales targets.",
"The writing style, renders the report containing these three sections displayed in a cascaded form, surrounded by market share pie charts, and the prose with headings such as “target market”, “competitors”, etc.",
"The foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting the present invention.",
"While the invention has been described with reference to various embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitations.",
"Further, although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein;",
"rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.",
"Those skilled in the art, having the benefit of the teachings of this specification, may effect numerous modifications thereto and changes may be made without departing from the scope and spirit of the invention in its aspects."
] |
TECHNICAL FIELD
The present invention relates to a selective growth technique for Group III-nitride materials and, more particularly, to the use of masking technique to form both polycrystalline and single crystal Group III-nitride films that can be preferentially processed to form selected growth areas.
BACKGROUND OF THE INVENTION
Group III nitrides, in particular, GaN, are of interest for many electronic and optoelectronic applications, including high temperature electronic devices, high-power microwave circuits, blue lasers and LEDs, as well as solar-blind photodetectors. For these applications, the semiconductor layers are grown epitaxially on a crystalline substrate. After the epitaxial growth, a masking layer is typically deposited on the surface and lithographically patterned. The pattern can then be transferred to the underlying semiconductor material by etching. There are several reasons why this patterning is needed, including device isolation, contact to underlying layers, and the formation of waveguides and laser facets.
GaN etching is commonly performed using a reactive ion etching (RIE) technique. An article entitled “Dry and Wet Etching for Group III-nitrides” by I. Adesida et al. appearing in MRS Internet Journal of Nitride Semiconductor Research , Vol. 4S1, No. G1.4, 1999, discussed in detail various prior art RIE and wet chemical etching techniques for GaN. One of the drawbacks of reactive ion etching includes the generation of ion-induced damage on the surface of the GaN film. Wet chemical etching produces significantly less damage and is often less costly and complex than RIE systems, thus making wet chemical etching an attractive alternative. However, epitaxial GaN (or Group III-nitrides in general) has been found to be resistant to wet chemical etching. In particular, the etch rates have been too slow for efficient processing. Further, the wet etch techniques have generally not been directional enough to produce sidewalls that mirror the masking material. To circumvent this problem, photo-enhanced electrochemical PPEC) has been developed. U.S. Pat. No. 5,773,369 issued to E. L. Hu et al on Jun. 30, 1998 discussed an exemplary PEC process for Group III nitrides where an ultra-violet light source and a metal mask layer is used. A bias is applied to the metal mask to effect the etch process. In general, a PEC process is ineffective in etching p-type and semi-insulating materials since there are not enough holes at the surface to allow the wet chemistry to progress and etch the material. Regardless of the process used, the etch depth is controlled by several factors, including—among others—the etch time, etch composition and sample temperature.
In some applications, it is desirable to perform an additional growth over already patterned semiconductor layers. With existing etch processes, it is very difficult to pattern any new layer selectively without damaging the previously grown layers. A need remains in the prior art, therefore, for a more controllable method of selectively regrowing and patterning Group III-nitride layers. Selective regrowth would, for example, enable the integration of various GaN-based devices on a single wafer (e.g., electronic devices with lasers or LEDs).
Summary of the Invention
The need remaining in the prior art is addressed by the present invention, which relates to a selective growth technique for Group III-nitride materials and, more particularly, to the use of masking technique to form both polycrystalline and single crystal Group III-nitride (for example, GaN) films that can be preferentially processed to form selected growth areas.
In accordance with the technique of the present invention, a selective growth and etch process is obtained by first depositing, then patterning, a suitable masking layer on a substrate. An epitaxial GaN (for example) film is then grown, using an appropriate process, on the patterned substrate. A single crystal material will form on the exposed substrate, with polycrystalline material forming on the masking layer. An etchant that is selective between the single crystal and polycrystalline material can then be used to remove the polycrystalline film. The remaining masking layer is then removed, leaving only the single crystal GaN material in the selected areas.
In a preferred embodiment of the present invention, the GaN is plasma deposited using a reactive nitrogen species. This process results in the required vertical growth of the GaN film over both the substrate and masking layer. The polycrystalline GaN film will include both N-polar and Ga-polar surfaces, while the single crystal material will exhibit only Ga-polar faces. In order to etch away the polycrystalline material, an etchant such as potassium hydroxide can be used, which is known to etch only the N-polar surface. The single crystal material will remain intact, and the masking layer material can then be removed. The thickness of the patterned, single crystal Ga layer is thus determined precisely by the thickness of the epitaxial growth, and is therefore more controllable than other prior art processes.
Other and further aspects of the present invention will become apparent during the course of the following discussion and by reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings,
FIG. 1 illustrates an exemplary substrate that may be used in the selective growth process of the present invention;
FIG. 2 illustrates the first processing step of the present invention, where a patterned masking layer is formed on the substrate surface;
FIG. 3 illustrates a subsequent step in the process of the present invention, subsequent to the epitaxial growth of a Group III-nitride (such as GaN) over both the exposed substrate and masking layer; and
FIG. 4 illustrates the final selected growth structure formed in accordance with the present invention, where the polycrystalline material and associated masking layer have been removed.
DETAILED DESCRIPTION
FIG. 1 illustrates, in a cross-sectional view, an exemplary substrate 10 that can be processed in accordance with the present invention to provide selective growth of a Group III-nitride film. Substrate 10 can comprise a variety of materials, including but not limited to, Al 2 O 3 , SiC and GaN. Further, substrate 10 does not necessarily need to be planar. Indeed, as illustrated in FIG. 1, exemplary substrate 10 is formed to include a first region 12 that is raised above a second region 14 . In general, the process of the present invention relates to forming a selective Group III-nitride layer on the exposed surface of substrate 10 . For the purposes of the present discussion, the formation of a selective GaN film will be discussed, although it is to be understood that various other Group III-nitrides can similarly be formed.
Referring to FIG. 2, the initial step in the process of the present invention is to form a masking layer 16 that is patterned to leave exposed those areas to be covered with the GaN material. In the exemplary arrangement as shown in FIG. 2, masking layer 16 is patterned to leave exposed a first surface area 18 (in region 12 ) and a second surface area 20 (in region 14 ). Any other suitable pattern can be used. In accordance with the present invention, the material used to form masking layer 16 is very important. In particular, the mask material must be stable at the temperatures used for epitaxial growth (e.g., temperatures in the range of 600° C. to 900° C.), and should not decompose or contaminate the epitaxial growth chamber. A preferred embodiment of the present invention utilizes conventional silicon dioxide as the masking material (other materials, for example, silicon nitride, may be used in the formation of the masking layer). In a conventional method of applying the masking layer, a uniform film of silicon dioxide is first disposed to completely cover the surface 22 of substrate 10 . Silicon dioxide masking layer 16 is then patterned to expose regions 18 and 20 , as shown in FIG. 2 .
Subsequent to the patterning of masking layer 16 , an epitaxial layer of the Group III-nitride (for example, GaN) is grown to cover the exposed surface. In accordance with the present invention, the technique used to grow the epitaxial layer is extremely important. For example, some techniques, such as metal-organic chemical vapor deposition (MOCVD) and chemical beam epitaxy (CBE) rely on the substrate surface to help crack the nitrogen precursor so as to form the active nitrogen needed for growth. Therefore, depending on the growth conditions, GaN grown by these techniques may not deposit directly on the surface of masking layer 16 . Indeed, GaN may grow laterally from the sides of the mask and, while laterally grown material is often of high quality, it prevents the vertical transfer of the mask pattern to the substrate, a necessary requirement of the selective process of the present invention. In accordance with the present invention, therefore, vertical growth of the epitaxial film is required in order to replicate the mask dimensions onto the substrate surface. One exemplary way to accomplish vertical growth is to use a reactive nitrogen species, such as that provided by a plasma source. Therefore, in accordance with the present invention, a plasma-deposited GaN film is preferred. It is to be understood, however, that any GaN growth technique capable of providing the necessary vertical growth may be used in accordance with the present invention.
FIG. 3 illustrates the structure of the present invention subsequent to forming a GaN layer using a plasma process with a reactive nitrogen species. Referring to FIG. 3, the use of a reactive nitrogen species results in the formation of a single-crystalline GaN semiconductor growth 24 and 26 over substrate-exposed regions 18 and 20 , respectively. Importantly, the use of a reactive nitrogen species results in the growth of a polycrystalline GaN material 28 over masking layer 16 . Both regions, as a result of the plasma process, are vertical growth regions, allowing for the precise transfer of edges 30 , 32 of masking layer 16 onto underlying substrate 10 (as shown in FIG. 4 and discussed in detail below).
In accordance with the present invention, the formation of selected growth GaN regions is then accomplished by removing (by etching) both the polycrystalline GaN and the underlying masking layer. The results of this etch step are shown in FIG. 4, which illustrates the selected, single crystal GaN regions 24 and 26 on substrate 10 . An important step in the process of the present invention relates to the selection of an etchant that will preferentially etch polycrystalline GaN with respect to single crystal GaN. As is well known, the chemical resistance of GaN depends strongly on the crystallographic plane of the material. In particular, there are no known chemicals that will etch a defect-free Ga-polar GaN surface (unless assisted by ultraviolet light or reactive ions, as described above). The N-polar surface, which is the face opposite the Ga-polar plane, can be etched, for example, by solutions of potassium hydroxide (or other etchants, such as sodium hydroxide or ammonium hydroxide). Therefore, when the structure as shown in FIG. 3 is immersed in an etchant that etches only the N-polar surface (such as potassium hydroxide), only polycrystalline GaN 28 will be removed, since only this material has exposed N-polar surfaces. Single crystal GaN (having only Ga-polar surfaces) will remain intact during the etching operation. Subsequent to the etching of polycrystalline GaN 28 , masking layer 26 can then be removed using any conventional etch that is selective between GaN and the masking material (such as hydrofluoric acid). The remaining structure, as illustrated in FIG. 4, thus includes “selective”, single crystal GaN regions 24 , 26 , where the thickness “t” of each region is determined precisely by the thickness of the epitaxial growth, and is therefore more controllable than the prior art non-selective growth processes discussed above.
Although the present invention has been described in connection with preferred embodiments in terms of, for example, certain materials for each layer and certain etchants for each step, it should be noted that various changes and modifications can be made and are apparent to those skilled in the art. Accordingly, such changes and modifications so far as encompassed by the appended claims are to be understood as included within the scope of the present invention. | A method of forming selected Group III-nitride regions uses a masking layer to cause differential growth between single crystal Group III-nitride material and polycrystalline Group III-nitride material. The epitaxial process is chosen to provide vertical growth so as to allow for replication of the mask edges at the defined limits for the selected regions. By using an etchant that is selective between polycrystalline and single crystal Group III-nitride material, the polycrystalline material (that grew over the mask layer) can be removed, leaving only the single crystal Group III-nitride (that grew over the exposed substrate material). | Concisely explain the essential features and purpose of the invention. | [
"TECHNICAL FIELD The present invention relates to a selective growth technique for Group III-nitride materials and, more particularly, to the use of masking technique to form both polycrystalline and single crystal Group III-nitride films that can be preferentially processed to form selected growth areas.",
"BACKGROUND OF THE INVENTION Group III nitrides, in particular, GaN, are of interest for many electronic and optoelectronic applications, including high temperature electronic devices, high-power microwave circuits, blue lasers and LEDs, as well as solar-blind photodetectors.",
"For these applications, the semiconductor layers are grown epitaxially on a crystalline substrate.",
"After the epitaxial growth, a masking layer is typically deposited on the surface and lithographically patterned.",
"The pattern can then be transferred to the underlying semiconductor material by etching.",
"There are several reasons why this patterning is needed, including device isolation, contact to underlying layers, and the formation of waveguides and laser facets.",
"GaN etching is commonly performed using a reactive ion etching (RIE) technique.",
"An article entitled “Dry and Wet Etching for Group III-nitrides”",
"by I. Adesida et al.",
"appearing in MRS Internet Journal of Nitride Semiconductor Research , Vol. 4S1, No. G1.4, 1999, discussed in detail various prior art RIE and wet chemical etching techniques for GaN.",
"One of the drawbacks of reactive ion etching includes the generation of ion-induced damage on the surface of the GaN film.",
"Wet chemical etching produces significantly less damage and is often less costly and complex than RIE systems, thus making wet chemical etching an attractive alternative.",
"However, epitaxial GaN (or Group III-nitrides in general) has been found to be resistant to wet chemical etching.",
"In particular, the etch rates have been too slow for efficient processing.",
"Further, the wet etch techniques have generally not been directional enough to produce sidewalls that mirror the masking material.",
"To circumvent this problem, photo-enhanced electrochemical PPEC) has been developed.",
"U.S. Pat. No. 5,773,369 issued to E. L. Hu et al on Jun. 30, 1998 discussed an exemplary PEC process for Group III nitrides where an ultra-violet light source and a metal mask layer is used.",
"A bias is applied to the metal mask to effect the etch process.",
"In general, a PEC process is ineffective in etching p-type and semi-insulating materials since there are not enough holes at the surface to allow the wet chemistry to progress and etch the material.",
"Regardless of the process used, the etch depth is controlled by several factors, including—among others—the etch time, etch composition and sample temperature.",
"In some applications, it is desirable to perform an additional growth over already patterned semiconductor layers.",
"With existing etch processes, it is very difficult to pattern any new layer selectively without damaging the previously grown layers.",
"A need remains in the prior art, therefore, for a more controllable method of selectively regrowing and patterning Group III-nitride layers.",
"Selective regrowth would, for example, enable the integration of various GaN-based devices on a single wafer (e.g., electronic devices with lasers or LEDs).",
"Summary of the Invention The need remaining in the prior art is addressed by the present invention, which relates to a selective growth technique for Group III-nitride materials and, more particularly, to the use of masking technique to form both polycrystalline and single crystal Group III-nitride (for example, GaN) films that can be preferentially processed to form selected growth areas.",
"In accordance with the technique of the present invention, a selective growth and etch process is obtained by first depositing, then patterning, a suitable masking layer on a substrate.",
"An epitaxial GaN (for example) film is then grown, using an appropriate process, on the patterned substrate.",
"A single crystal material will form on the exposed substrate, with polycrystalline material forming on the masking layer.",
"An etchant that is selective between the single crystal and polycrystalline material can then be used to remove the polycrystalline film.",
"The remaining masking layer is then removed, leaving only the single crystal GaN material in the selected areas.",
"In a preferred embodiment of the present invention, the GaN is plasma deposited using a reactive nitrogen species.",
"This process results in the required vertical growth of the GaN film over both the substrate and masking layer.",
"The polycrystalline GaN film will include both N-polar and Ga-polar surfaces, while the single crystal material will exhibit only Ga-polar faces.",
"In order to etch away the polycrystalline material, an etchant such as potassium hydroxide can be used, which is known to etch only the N-polar surface.",
"The single crystal material will remain intact, and the masking layer material can then be removed.",
"The thickness of the patterned, single crystal Ga layer is thus determined precisely by the thickness of the epitaxial growth, and is therefore more controllable than other prior art processes.",
"Other and further aspects of the present invention will become apparent during the course of the following discussion and by reference to the accompanying drawings.",
"BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the drawings, FIG. 1 illustrates an exemplary substrate that may be used in the selective growth process of the present invention;",
"FIG. 2 illustrates the first processing step of the present invention, where a patterned masking layer is formed on the substrate surface;",
"FIG. 3 illustrates a subsequent step in the process of the present invention, subsequent to the epitaxial growth of a Group III-nitride (such as GaN) over both the exposed substrate and masking layer;",
"and FIG. 4 illustrates the final selected growth structure formed in accordance with the present invention, where the polycrystalline material and associated masking layer have been removed.",
"DETAILED DESCRIPTION FIG. 1 illustrates, in a cross-sectional view, an exemplary substrate 10 that can be processed in accordance with the present invention to provide selective growth of a Group III-nitride film.",
"Substrate 10 can comprise a variety of materials, including but not limited to, Al 2 O 3 , SiC and GaN.",
"Further, substrate 10 does not necessarily need to be planar.",
"Indeed, as illustrated in FIG. 1, exemplary substrate 10 is formed to include a first region 12 that is raised above a second region 14 .",
"In general, the process of the present invention relates to forming a selective Group III-nitride layer on the exposed surface of substrate 10 .",
"For the purposes of the present discussion, the formation of a selective GaN film will be discussed, although it is to be understood that various other Group III-nitrides can similarly be formed.",
"Referring to FIG. 2, the initial step in the process of the present invention is to form a masking layer 16 that is patterned to leave exposed those areas to be covered with the GaN material.",
"In the exemplary arrangement as shown in FIG. 2, masking layer 16 is patterned to leave exposed a first surface area 18 (in region 12 ) and a second surface area 20 (in region 14 ).",
"Any other suitable pattern can be used.",
"In accordance with the present invention, the material used to form masking layer 16 is very important.",
"In particular, the mask material must be stable at the temperatures used for epitaxial growth (e.g., temperatures in the range of 600° C. to 900° C.), and should not decompose or contaminate the epitaxial growth chamber.",
"A preferred embodiment of the present invention utilizes conventional silicon dioxide as the masking material (other materials, for example, silicon nitride, may be used in the formation of the masking layer).",
"In a conventional method of applying the masking layer, a uniform film of silicon dioxide is first disposed to completely cover the surface 22 of substrate 10 .",
"Silicon dioxide masking layer 16 is then patterned to expose regions 18 and 20 , as shown in FIG. 2 .",
"Subsequent to the patterning of masking layer 16 , an epitaxial layer of the Group III-nitride (for example, GaN) is grown to cover the exposed surface.",
"In accordance with the present invention, the technique used to grow the epitaxial layer is extremely important.",
"For example, some techniques, such as metal-organic chemical vapor deposition (MOCVD) and chemical beam epitaxy (CBE) rely on the substrate surface to help crack the nitrogen precursor so as to form the active nitrogen needed for growth.",
"Therefore, depending on the growth conditions, GaN grown by these techniques may not deposit directly on the surface of masking layer 16 .",
"Indeed, GaN may grow laterally from the sides of the mask and, while laterally grown material is often of high quality, it prevents the vertical transfer of the mask pattern to the substrate, a necessary requirement of the selective process of the present invention.",
"In accordance with the present invention, therefore, vertical growth of the epitaxial film is required in order to replicate the mask dimensions onto the substrate surface.",
"One exemplary way to accomplish vertical growth is to use a reactive nitrogen species, such as that provided by a plasma source.",
"Therefore, in accordance with the present invention, a plasma-deposited GaN film is preferred.",
"It is to be understood, however, that any GaN growth technique capable of providing the necessary vertical growth may be used in accordance with the present invention.",
"FIG. 3 illustrates the structure of the present invention subsequent to forming a GaN layer using a plasma process with a reactive nitrogen species.",
"Referring to FIG. 3, the use of a reactive nitrogen species results in the formation of a single-crystalline GaN semiconductor growth 24 and 26 over substrate-exposed regions 18 and 20 , respectively.",
"Importantly, the use of a reactive nitrogen species results in the growth of a polycrystalline GaN material 28 over masking layer 16 .",
"Both regions, as a result of the plasma process, are vertical growth regions, allowing for the precise transfer of edges 30 , 32 of masking layer 16 onto underlying substrate 10 (as shown in FIG. 4 and discussed in detail below).",
"In accordance with the present invention, the formation of selected growth GaN regions is then accomplished by removing (by etching) both the polycrystalline GaN and the underlying masking layer.",
"The results of this etch step are shown in FIG. 4, which illustrates the selected, single crystal GaN regions 24 and 26 on substrate 10 .",
"An important step in the process of the present invention relates to the selection of an etchant that will preferentially etch polycrystalline GaN with respect to single crystal GaN.",
"As is well known, the chemical resistance of GaN depends strongly on the crystallographic plane of the material.",
"In particular, there are no known chemicals that will etch a defect-free Ga-polar GaN surface (unless assisted by ultraviolet light or reactive ions, as described above).",
"The N-polar surface, which is the face opposite the Ga-polar plane, can be etched, for example, by solutions of potassium hydroxide (or other etchants, such as sodium hydroxide or ammonium hydroxide).",
"Therefore, when the structure as shown in FIG. 3 is immersed in an etchant that etches only the N-polar surface (such as potassium hydroxide), only polycrystalline GaN 28 will be removed, since only this material has exposed N-polar surfaces.",
"Single crystal GaN (having only Ga-polar surfaces) will remain intact during the etching operation.",
"Subsequent to the etching of polycrystalline GaN 28 , masking layer 26 can then be removed using any conventional etch that is selective between GaN and the masking material (such as hydrofluoric acid).",
"The remaining structure, as illustrated in FIG. 4, thus includes “selective”, single crystal GaN regions 24 , 26 , where the thickness “t”",
"of each region is determined precisely by the thickness of the epitaxial growth, and is therefore more controllable than the prior art non-selective growth processes discussed above.",
"Although the present invention has been described in connection with preferred embodiments in terms of, for example, certain materials for each layer and certain etchants for each step, it should be noted that various changes and modifications can be made and are apparent to those skilled in the art.",
"Accordingly, such changes and modifications so far as encompassed by the appended claims are to be understood as included within the scope of the present invention."
] |
BACKGROUND OF THE INVENTION
The present invention relates to a hinge mechanism, more particularly, but not exclusively, to a hinge mechanism for a portable radio communication apparatus.
Certain designs of portable radio communication apparatus, such as radio telephones, are provided in two pivoted parts consisting of a main body and a cover member (or flip) which is usually hinged at the top or bottom end of the body. The cover member can be moved between a closed position overlaying a portion of the face of the body, typically the keypad, and an open position pivoted away from the body, exposing the keypad and ready for use. The main body houses the majority of the electronic components of the radiotelephone, whilst the flip sometimes houses an earpiece, or microphone or LCD display. Such radio telephones are generally known as flip or folding phones, and as well as offering protection for the keypad from inadvertent activation, can also make for a more compact design of phone.
A wide variety of folding phones are currently available, employing many different hinge solutions. Known hinge mechanisms range from relatively simple pin/recess arrangements to more sophisticated assemblies comprising springs, cams, followers and latching mechanisms.
SUMMARY OF THE INVENTION
The challenge faced by the present inventors was to design an alternative improved hinge mechanism which met the main criteria of:
reliability, in terms of the number of opening/closing operations,
smooth motion and good action, offering a slight resistance to movement,
providing detent bias in the closed and open positions, and
a positive overideable flip stop in the open position
ease of assembly.
Accordingly, in one aspect the present invention provides a hinge mechanism for pivotally connecting first and second housings of a portable electronic device for movement between closed and open positions, the mechanism comprising a hinge shaft mounted for rotation with the first housing and providing a camming surface, and resilient means mounted for rotation with the second housing and arranged to cooperate with the camming surface so as respectively to load the resilient means corresponding to different orientations with respect to the camming surface for relative rotation therebetween
By means of the invention, the hinge mechanism provides a varying torque between the resilient means and the camming surface which causes relative rotation of the resilient means and the camming surface.
In a preferred embodiment, when the first and second housings are in the open position they are mutually biased towards the open position, and when the first and second housings are in the closed position they are mutually biased towards the closed position.
BRIEF DESCRIPTION OF THE DRAWINGS
Thus, the hinge mechanism provides a detent torque for the housings in the closed and open positions, and also offers some resistance to rotational movement which enhances the feel of the opening and closing motion.
It is preferred that the camming surface is shaped to define stable and unstable orientations for the resilient means, the resilient means tending towards the stable orientation in said open and closed positions. In this way, the resilient means indexes around the camming surface.
In a preferred embodiment the resilient means comprises a pair of spring arms acting on opposite sides of the camming surface.
Advantageously, the resilient means is carried in a retainer and the retainer is coupled to the second housing. This affords the hinge mechanism a modular design. The retainer conveniently comprises a longitudinally split tube, each half of the tube carrying respective resilient means.
It is preferred that the camming surface comprises opposing planar surfaces and that the planes defined by the planar surfaces are offset from the vertical axis of the hinge shaft. This conveniently provides for the detent torque.
In an advantageous embodiment, the hinge shaft carries a projection adapted to abut a corresponding projection provided on the second housing, whereby the abutment of the projections supports the second housing in relation to the first housing in said open position. Optionally, said projections are adapted to traverse one another if the housings are extended beyond said open position.
The invention extends to a radio telephone having first and second housings and including a hinge mechanism as hereinbefore defined for pivotally connecting said housings.
The invention will now be described by way of example with reference to the following drawings in which:
FIG. 1 is a front perspective view of a radiotelephone in a closed position and incorporating a hinge mechanism in accordance with the present invention;
FIG. 2 is front perspective view of a radiotelephone in an open position and incorporating a hinge mechanism in accordance with the present invention;
FIG. 3 a is an exploded isometric view of a hinge module of a preferred embodiment of the present invention;
FIG. 3 b is an isometric view an assembled hinge module of FIG. 3 a;
FIG. 4 is a schematic cross sectional view of a camming profile of the preferred embodiment;
FIGS. 5 a to 5 d are schematic cross sectional views of the interaction of the camming surface of FIG. 4 with a pair of leaf springs;
FIG. 6 a is an exploded isometric view of the hinge module of FIG. 3 b in a housing of the radiotelephone of FIGS. 1 and 2;
FIG. 6 b is a perspective view of a hinge knuckle of the preferred embodiment;
FIGS. 7 a and 7 b are schematic cross sectional views of the hinge with the housing of FIG. 6 in respective closed and open positions; and
FIG. 8 is an isometric view of the safety-stop support feature of the preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring initially to FIGS. 1 and 2, there is shown a portable radiotelephone 10 comprising a main body 12 pivotally connected to a flip 14 by a hinge 16 having an axis of rotation indicated by the line AB. FIGS. 1 and 2 show the flip 14 in respective closed and open positions in relation to the main body 12 .
The main body 12 comprises an upper casing 18 and lower casing 20 which together house the main internal control circuitry of the radiotelephone 10 . The upper casing 18 carries a keypad 22 and power button 24 , and forms, towards the front end, a chin 26 , below which is housed a microphone. The rear end of the upper casing upsweeps to a pair of knuckles 28 of the hinge 16 . A slidable antenna 30 is provided at the side of the main body 12 .
The flip 14 likewise comprises an upper casing 32 and the lower casing 34 which join together to house further electronic components such as an LCD display 36 , an earpiece 38 , and associated circuitry. The foot of the flip 14 is formed into a tube 39 and encases part of the hinge module.
The microphone and the earpiece 38 are positioned at opposite ends of the two parts of the radiotelephone to maximise the distance between them, such that this distance approximates the distance between the ear and the mouth of the user.
With the flip 14 in the closed position of FIG. 1 it covers the keypad 22 and its upper edge skirts the chin 26 . In the open position of the FIG. 2, the flip 14 is pivotally spaced from the main body 12 and the radiotelephone 10 is ready for use. It is notable that in the open position with the radiotelephone held up to a user's ear, the flip 14 at least partially screens the antenna 30 and this provides useful blocking against radio magnetic waves.
Turning to FIG. 3 a, a hinge module 40 is shown in the exploded isometric view as comprising a central hinge shaft 42 in part sandwiched by a pair of leaf springs 44 which in turn are encased by respective halves of a spring retainer tube 46 .
The hinge shaft 42 is a one-piece integral unit consisting of several distinguishable sections: a shank 48 and a cam section 50 separated by a raised collar 52 , the two ends of the shaft being provided with rectangular locating bosses 54 for mounting in the hinge knuckles 28 (to be described later).The shank 48 has a generally circular cross section and leads to the raised collar 52 which carries a radial lug 56 forming part of the stop feature of the hinge mechanism. Inward of the collar 52 is the cam section 50 which consists of two spaced apart camming surfaces 58 . Each camming surface 58 is formed from opposite pairs of regions where the surface of the hinge shaft 42 is substantially flat. A cross section of a camming surface 58 is illustrated in FIG. 4 and comprises two opposite substantially parallel flat major faces 60 connected by two opposite rounded minor faces 62 . Here, it should be explained that the planes of the flat major faces 60 are not parallel to the vertical axes of the locating bosses 54 . Rather, the planes of the flat major faces are offset by 10° from the vertical defined by the vertical axes of locating bosses 54 for a purpose which will become apparent later. The camming surfaces 58 are closed at their outer ends by a pair of shoulders formed by the flange walls of the distal locating boss 54 and the collar 52 .
Turning to the pair of leaf springs 44 , since these are identical, for clarity the description will relate to one of the pair. The leaf spring 44 is elongate and generally planar although it has a convex bow along its length. The spring 44 has a stem 64 joining its ends which are spatulate 66 and having a width greater than that of the stem 64 . The width of the spatulate ends 66 is selected to match or be slightly wider than the width of the major faces 60 of the camming surfaces 58 of the hinge shaft 42 so as to apply a more even force over the camming surfaces 58 . In a natural unstressed state the spring 44 has a bowed height of typically 1.85 mm.
Moving on to the spring retainer tube 46 , this consists of two halves of a longitudinally split cylindrical tube, each halve holding one of the pair of leaf spring 44 . Formed in the side wall of a retainer halve 46 is a pair of jaws 68 into which the leaf spring 44 is pressed clipped into position. Each of the retainer halves 46 is provided with corresponding lugs 70 and catches 72 so that the two halves can be latched together. It is advantageous that the spring retainer halves are “handed” in that the correspondence of the lugs 70 and catches 72 is such that any two halves can be assembled despite being mutually opposite; this obviates the need for separate left and right handed retainer halves. Whilst the side walls 74 of the retainer tubes are generally curved, the upper and lower walls are flat 76 .
In order to assemble the hinge module, the leaf springs 44 are first clip locked into respective halves of the retainers 46 . Next the spring retainer halves 46 are brought together lengthwise around the camming section 50 of the hinge shaft 42 and are latched to one another. This causes loading of the leaf springs 44 which press against camming surfaces 58 and flex outwards against the shoulders formed by the flange walls of the distal locating boss 54 and the collar 52 . The bowed height of the springs in this loaded state is approximately 1.7 mm. An assembled hinge module is shown in FIG. 3 b.
It is notable that it is only possible to latch the spring retainers 46 together once they are correctly aligned in relation to the hinge shaft 42 , because at other locations along the shaft 42 its diameter is too large for the retainer halves to fit together.
The hinge mechanism 40 operates as follows. Because in its natural condition the bow of the leaf springs 44 is greater than the space between the retainer 46 and the hinge shaft 42 camming surface, the leaf springs 44 are compressed slightly and pre-loads are introduced in the springs which give rise to spring forces on the camming surfaces. The spatulate ends 66 of the leaf springs 44 contact the camming surfaces 58 at tangents, thus the spring forces on the camming surfaces 58 are directed radially inwards. As the relative orientation of the leaf springs 44 with respect to the shaft 42 changes, so they adopt successive stable and unstable positions. At orientations when the spatulate ends 66 lie flat against the major faces 60 of the camming surface as in FIG. 5 a, the springs 44 are in a stable position and there is no net torque being applied to the hinge shaft 42 . In the orientation shown in FIG. 5 b, the springs have moved through 90° and the spatulate ends 66 press on the opposing tips of the minor faces 62 of the camming surface 58 and momentarily reach an equilibrium.
It will be understood with reference to FIGS. 5 c and 5 d that at other orientations around the camming surface 58 , ie. partway between the major faces 60 and the tips of the minor faces 62 , the leaf springs 44 are unstable inasmuch as the spatulate ends 66 apply spring forces against the camming surfaces 58 in such a manner as to induce a torque which causes the leaf springs 44 to bias towards the flat major faces 60 . If from this stable position, there is relative rotation between the leaf springs 44 and the shaft 42 , the springs 44 apply an opposing torque which acts to restore the leaf springs 44 to stable major faces. With appropriate spring loading and cam dimensions this action can be a snap action. Furthermore, it can seen that relative rotation of the leaf springs 44 and the camming surface 58 represents an indexing action.
Referring now to FIG. 6 a, the assembled hinge module is disposed in the hinge tube 39 of the flip 14 as illustrated. Inside the tube 39 the flat sides of the spring retainer are shaped to mate with opposing flat beds 78 provided by crosswise rails in the tube 39 and in this way prevent relative rotation between the hinge module 40 and the flip, effectively rotatably keying the two together. The step of assembling the hinge module 40 in the tube 39 requires that the hinge module 40 is inserted longitudinally from one end of the flip tube 39 having a square opening, until the inward edge of the spring retainer 46 abuts the final rail to stop it moving in any further.
With the hinge module inserted in the flip tube 39 , the flip 14 is joined to the upper casing 18 of the main body 12 . Circumferential projections 80 extending laterally from the ends of the flip tubes mate with corresponding recessed slots 82 in the inside edges of the knuckles 28 of the upper casing 18 (see FIG. 6 b ). This provides for the correct locating of the flip 14 and also ensures continuity of the hinge connection. The rectangular locating bosses 54 of the hinge shaft 42 are received in vertical slots 82 provided in each of the knuckles 28 of the upper casing 18 . Accordingly, the shaft 42 is fixed in relation to the knuckle 28 and the reaction force to the turning force of the hinge shaft 42 is provided by the knuckle 28 in the upper casing 18 .
The operation of the hinge and the pivoting of the flip relative to the main body is of course based on the mechanism of the hinge module already described above with reference to FIGS. 5 a and 5 b . The flip 14 having keyed into it the hinge module 40 containing leaf springs pivots 44 around the hinge shaft 42 which remains relatively static in the main body 12 . In the angular orientation associated with the flip 14 being in the closed position the configuration of the spatulate ends 66 of the leaf springs 44 in relation to the camming surfaces 58 is as shown in FIG. 7 a . Rather than lying squarely on major faces 60 of the camming surfaces 58 , the spatulate ends 66 press against opposite shoulders of the camming surface 58 . This is due to the offset of the planes of the major faces 60 from the vertical. Accordingly, the leaf springs 44 bias towards the major faces 60 and as a result together give rise to a net clockwise turning force which is transmitted to the flip 14 causing it to be urged towards the main body 12 . Since the upper edge of the flip 14 abuts the chin 26 of the radiotelephone 10 at a horizontal, a standing torque or detent torque is set up on the flip 14 . In this way, in the closed position the flip 14 offers a certain amount of in-built resistance to being opened and prevents it from having a sloppy feel.
Conversely, with the flip 14 in the open position the configuration of the leaf spring 44 and the hinge shaft 42 is as illustrated in FIG. 7 b . Opening of the flip 14 is facilitated by formations on the side edges and the rear of the flip. In this open position the flip 14 has travelled through 160° and the spatulate ends 66 of the leaf springs 44 have reversed orientation and press against the other pair of shoulders of the camming surface 58 . Again, the spatulate ends 66 do not lie on the major faces 60 and accordingly the leaf springs 44 now transmit an anti-clockwise turning force on the flip. The flip 14 however is prevented from moving to adopt this position by a stop feature 52 / 84 .
The stop feature is shown in FIG. 8 and comprises the raised lug 56 on the collar 52 of the hinge shaft which engages a short axial lip 84 spanning two adjacent rails extending from the internal wall of the flip hinge tube 39 . When the flip is moved to the open position, the axial lip 84 approaches the lug 56 and at 160° opening catches against it. Due to the in-built detent torque of the springs 44 and camming surface 58 in this position, the flip 14 is biased in the open position. The stop feature 52 / 84 is designed to be positive enough to provide sufficient support for the flip 14 when it is pressed against a user's ear during a call.
However, a combination of the tolerances of the components and the inherent elasticity of the hinge materials allows the lug 56 to ride over the lip 84 if excessive force is applied to the flip. For example, if the flip 14 is in the open condition and someone inadvertently sits on the phone 10 , the lug 56 overrides the axial lip 84 and the flip 14 can travel passed the 160° opening angle without breaking the flip 14 , hinge 40 or stop feature 52 / 84 . In this event, the leaf spring 44 indexes rounds to the stable major face 60 . To return the flip, the user holding the main body and flip manually snaps the lug 56 back over the axial lip 84 . As is apparent, this override property provides a beneficial safety feature for the radiotelephone 10 against damage.
It will be readily understood that alternative arrangements to those described above with reference to the specific embodiment can be made within the inventive concept as defined in the appended claims. For example the resilient means, instead of being a leaf spring could be an elastomeric composite.
Each feature disclosed in this specification (which term includes the claims) and/or shown in the drawings may be incorporated in the invention independently of other disclosed and/or illustrated features.
The appended abstract as filed herewith is included in the specification by reference. | A hinge mechanism for pivotally connecting first and second housings of a portable electronic device for movement between closed and open positions, the mechanism comprising a hinge shaft mounted for rotation with the first housing and providing a camming surface, and resilient means mounted for rotation with the second housing and arranged to cooperate with the camming surface so as to vary loading of the resilient means on the camming surface for relative rotation therebetween. | Summarize the patent information, clearly outlining the technical challenges and proposed solutions. | [
"BACKGROUND OF THE INVENTION The present invention relates to a hinge mechanism, more particularly, but not exclusively, to a hinge mechanism for a portable radio communication apparatus.",
"Certain designs of portable radio communication apparatus, such as radio telephones, are provided in two pivoted parts consisting of a main body and a cover member (or flip) which is usually hinged at the top or bottom end of the body.",
"The cover member can be moved between a closed position overlaying a portion of the face of the body, typically the keypad, and an open position pivoted away from the body, exposing the keypad and ready for use.",
"The main body houses the majority of the electronic components of the radiotelephone, whilst the flip sometimes houses an earpiece, or microphone or LCD display.",
"Such radio telephones are generally known as flip or folding phones, and as well as offering protection for the keypad from inadvertent activation, can also make for a more compact design of phone.",
"A wide variety of folding phones are currently available, employing many different hinge solutions.",
"Known hinge mechanisms range from relatively simple pin/recess arrangements to more sophisticated assemblies comprising springs, cams, followers and latching mechanisms.",
"SUMMARY OF THE INVENTION The challenge faced by the present inventors was to design an alternative improved hinge mechanism which met the main criteria of: reliability, in terms of the number of opening/closing operations, smooth motion and good action, offering a slight resistance to movement, providing detent bias in the closed and open positions, and a positive overideable flip stop in the open position ease of assembly.",
"Accordingly, in one aspect the present invention provides a hinge mechanism for pivotally connecting first and second housings of a portable electronic device for movement between closed and open positions, the mechanism comprising a hinge shaft mounted for rotation with the first housing and providing a camming surface, and resilient means mounted for rotation with the second housing and arranged to cooperate with the camming surface so as respectively to load the resilient means corresponding to different orientations with respect to the camming surface for relative rotation therebetween By means of the invention, the hinge mechanism provides a varying torque between the resilient means and the camming surface which causes relative rotation of the resilient means and the camming surface.",
"In a preferred embodiment, when the first and second housings are in the open position they are mutually biased towards the open position, and when the first and second housings are in the closed position they are mutually biased towards the closed position.",
"BRIEF DESCRIPTION OF THE DRAWINGS Thus, the hinge mechanism provides a detent torque for the housings in the closed and open positions, and also offers some resistance to rotational movement which enhances the feel of the opening and closing motion.",
"It is preferred that the camming surface is shaped to define stable and unstable orientations for the resilient means, the resilient means tending towards the stable orientation in said open and closed positions.",
"In this way, the resilient means indexes around the camming surface.",
"In a preferred embodiment the resilient means comprises a pair of spring arms acting on opposite sides of the camming surface.",
"Advantageously, the resilient means is carried in a retainer and the retainer is coupled to the second housing.",
"This affords the hinge mechanism a modular design.",
"The retainer conveniently comprises a longitudinally split tube, each half of the tube carrying respective resilient means.",
"It is preferred that the camming surface comprises opposing planar surfaces and that the planes defined by the planar surfaces are offset from the vertical axis of the hinge shaft.",
"This conveniently provides for the detent torque.",
"In an advantageous embodiment, the hinge shaft carries a projection adapted to abut a corresponding projection provided on the second housing, whereby the abutment of the projections supports the second housing in relation to the first housing in said open position.",
"Optionally, said projections are adapted to traverse one another if the housings are extended beyond said open position.",
"The invention extends to a radio telephone having first and second housings and including a hinge mechanism as hereinbefore defined for pivotally connecting said housings.",
"The invention will now be described by way of example with reference to the following drawings in which: FIG. 1 is a front perspective view of a radiotelephone in a closed position and incorporating a hinge mechanism in accordance with the present invention;",
"FIG. 2 is front perspective view of a radiotelephone in an open position and incorporating a hinge mechanism in accordance with the present invention;",
"FIG. 3 a is an exploded isometric view of a hinge module of a preferred embodiment of the present invention;",
"FIG. 3 b is an isometric view an assembled hinge module of FIG. 3 a;",
"FIG. 4 is a schematic cross sectional view of a camming profile of the preferred embodiment;",
"FIGS. 5 a to 5 d are schematic cross sectional views of the interaction of the camming surface of FIG. 4 with a pair of leaf springs;",
"FIG. 6 a is an exploded isometric view of the hinge module of FIG. 3 b in a housing of the radiotelephone of FIGS. 1 and 2;",
"FIG. 6 b is a perspective view of a hinge knuckle of the preferred embodiment;",
"FIGS. 7 a and 7 b are schematic cross sectional views of the hinge with the housing of FIG. 6 in respective closed and open positions;",
"and FIG. 8 is an isometric view of the safety-stop support feature of the preferred embodiment of the invention.",
"DETAILED DESCRIPTION OF THE INVENTION Referring initially to FIGS. 1 and 2, there is shown a portable radiotelephone 10 comprising a main body 12 pivotally connected to a flip 14 by a hinge 16 having an axis of rotation indicated by the line AB.",
"FIGS. 1 and 2 show the flip 14 in respective closed and open positions in relation to the main body 12 .",
"The main body 12 comprises an upper casing 18 and lower casing 20 which together house the main internal control circuitry of the radiotelephone 10 .",
"The upper casing 18 carries a keypad 22 and power button 24 , and forms, towards the front end, a chin 26 , below which is housed a microphone.",
"The rear end of the upper casing upsweeps to a pair of knuckles 28 of the hinge 16 .",
"A slidable antenna 30 is provided at the side of the main body 12 .",
"The flip 14 likewise comprises an upper casing 32 and the lower casing 34 which join together to house further electronic components such as an LCD display 36 , an earpiece 38 , and associated circuitry.",
"The foot of the flip 14 is formed into a tube 39 and encases part of the hinge module.",
"The microphone and the earpiece 38 are positioned at opposite ends of the two parts of the radiotelephone to maximise the distance between them, such that this distance approximates the distance between the ear and the mouth of the user.",
"With the flip 14 in the closed position of FIG. 1 it covers the keypad 22 and its upper edge skirts the chin 26 .",
"In the open position of the FIG. 2, the flip 14 is pivotally spaced from the main body 12 and the radiotelephone 10 is ready for use.",
"It is notable that in the open position with the radiotelephone held up to a user's ear, the flip 14 at least partially screens the antenna 30 and this provides useful blocking against radio magnetic waves.",
"Turning to FIG. 3 a, a hinge module 40 is shown in the exploded isometric view as comprising a central hinge shaft 42 in part sandwiched by a pair of leaf springs 44 which in turn are encased by respective halves of a spring retainer tube 46 .",
"The hinge shaft 42 is a one-piece integral unit consisting of several distinguishable sections: a shank 48 and a cam section 50 separated by a raised collar 52 , the two ends of the shaft being provided with rectangular locating bosses 54 for mounting in the hinge knuckles 28 (to be described later).",
"The shank 48 has a generally circular cross section and leads to the raised collar 52 which carries a radial lug 56 forming part of the stop feature of the hinge mechanism.",
"Inward of the collar 52 is the cam section 50 which consists of two spaced apart camming surfaces 58 .",
"Each camming surface 58 is formed from opposite pairs of regions where the surface of the hinge shaft 42 is substantially flat.",
"A cross section of a camming surface 58 is illustrated in FIG. 4 and comprises two opposite substantially parallel flat major faces 60 connected by two opposite rounded minor faces 62 .",
"Here, it should be explained that the planes of the flat major faces 60 are not parallel to the vertical axes of the locating bosses 54 .",
"Rather, the planes of the flat major faces are offset by 10° from the vertical defined by the vertical axes of locating bosses 54 for a purpose which will become apparent later.",
"The camming surfaces 58 are closed at their outer ends by a pair of shoulders formed by the flange walls of the distal locating boss 54 and the collar 52 .",
"Turning to the pair of leaf springs 44 , since these are identical, for clarity the description will relate to one of the pair.",
"The leaf spring 44 is elongate and generally planar although it has a convex bow along its length.",
"The spring 44 has a stem 64 joining its ends which are spatulate 66 and having a width greater than that of the stem 64 .",
"The width of the spatulate ends 66 is selected to match or be slightly wider than the width of the major faces 60 of the camming surfaces 58 of the hinge shaft 42 so as to apply a more even force over the camming surfaces 58 .",
"In a natural unstressed state the spring 44 has a bowed height of typically 1.85 mm.",
"Moving on to the spring retainer tube 46 , this consists of two halves of a longitudinally split cylindrical tube, each halve holding one of the pair of leaf spring 44 .",
"Formed in the side wall of a retainer halve 46 is a pair of jaws 68 into which the leaf spring 44 is pressed clipped into position.",
"Each of the retainer halves 46 is provided with corresponding lugs 70 and catches 72 so that the two halves can be latched together.",
"It is advantageous that the spring retainer halves are “handed”",
"in that the correspondence of the lugs 70 and catches 72 is such that any two halves can be assembled despite being mutually opposite;",
"this obviates the need for separate left and right handed retainer halves.",
"Whilst the side walls 74 of the retainer tubes are generally curved, the upper and lower walls are flat 76 .",
"In order to assemble the hinge module, the leaf springs 44 are first clip locked into respective halves of the retainers 46 .",
"Next the spring retainer halves 46 are brought together lengthwise around the camming section 50 of the hinge shaft 42 and are latched to one another.",
"This causes loading of the leaf springs 44 which press against camming surfaces 58 and flex outwards against the shoulders formed by the flange walls of the distal locating boss 54 and the collar 52 .",
"The bowed height of the springs in this loaded state is approximately 1.7 mm.",
"An assembled hinge module is shown in FIG. 3 b. It is notable that it is only possible to latch the spring retainers 46 together once they are correctly aligned in relation to the hinge shaft 42 , because at other locations along the shaft 42 its diameter is too large for the retainer halves to fit together.",
"The hinge mechanism 40 operates as follows.",
"Because in its natural condition the bow of the leaf springs 44 is greater than the space between the retainer 46 and the hinge shaft 42 camming surface, the leaf springs 44 are compressed slightly and pre-loads are introduced in the springs which give rise to spring forces on the camming surfaces.",
"The spatulate ends 66 of the leaf springs 44 contact the camming surfaces 58 at tangents, thus the spring forces on the camming surfaces 58 are directed radially inwards.",
"As the relative orientation of the leaf springs 44 with respect to the shaft 42 changes, so they adopt successive stable and unstable positions.",
"At orientations when the spatulate ends 66 lie flat against the major faces 60 of the camming surface as in FIG. 5 a, the springs 44 are in a stable position and there is no net torque being applied to the hinge shaft 42 .",
"In the orientation shown in FIG. 5 b, the springs have moved through 90° and the spatulate ends 66 press on the opposing tips of the minor faces 62 of the camming surface 58 and momentarily reach an equilibrium.",
"It will be understood with reference to FIGS. 5 c and 5 d that at other orientations around the camming surface 58 , ie.",
"partway between the major faces 60 and the tips of the minor faces 62 , the leaf springs 44 are unstable inasmuch as the spatulate ends 66 apply spring forces against the camming surfaces 58 in such a manner as to induce a torque which causes the leaf springs 44 to bias towards the flat major faces 60 .",
"If from this stable position, there is relative rotation between the leaf springs 44 and the shaft 42 , the springs 44 apply an opposing torque which acts to restore the leaf springs 44 to stable major faces.",
"With appropriate spring loading and cam dimensions this action can be a snap action.",
"Furthermore, it can seen that relative rotation of the leaf springs 44 and the camming surface 58 represents an indexing action.",
"Referring now to FIG. 6 a, the assembled hinge module is disposed in the hinge tube 39 of the flip 14 as illustrated.",
"Inside the tube 39 the flat sides of the spring retainer are shaped to mate with opposing flat beds 78 provided by crosswise rails in the tube 39 and in this way prevent relative rotation between the hinge module 40 and the flip, effectively rotatably keying the two together.",
"The step of assembling the hinge module 40 in the tube 39 requires that the hinge module 40 is inserted longitudinally from one end of the flip tube 39 having a square opening, until the inward edge of the spring retainer 46 abuts the final rail to stop it moving in any further.",
"With the hinge module inserted in the flip tube 39 , the flip 14 is joined to the upper casing 18 of the main body 12 .",
"Circumferential projections 80 extending laterally from the ends of the flip tubes mate with corresponding recessed slots 82 in the inside edges of the knuckles 28 of the upper casing 18 (see FIG. 6 b ).",
"This provides for the correct locating of the flip 14 and also ensures continuity of the hinge connection.",
"The rectangular locating bosses 54 of the hinge shaft 42 are received in vertical slots 82 provided in each of the knuckles 28 of the upper casing 18 .",
"Accordingly, the shaft 42 is fixed in relation to the knuckle 28 and the reaction force to the turning force of the hinge shaft 42 is provided by the knuckle 28 in the upper casing 18 .",
"The operation of the hinge and the pivoting of the flip relative to the main body is of course based on the mechanism of the hinge module already described above with reference to FIGS. 5 a and 5 b .",
"The flip 14 having keyed into it the hinge module 40 containing leaf springs pivots 44 around the hinge shaft 42 which remains relatively static in the main body 12 .",
"In the angular orientation associated with the flip 14 being in the closed position the configuration of the spatulate ends 66 of the leaf springs 44 in relation to the camming surfaces 58 is as shown in FIG. 7 a .",
"Rather than lying squarely on major faces 60 of the camming surfaces 58 , the spatulate ends 66 press against opposite shoulders of the camming surface 58 .",
"This is due to the offset of the planes of the major faces 60 from the vertical.",
"Accordingly, the leaf springs 44 bias towards the major faces 60 and as a result together give rise to a net clockwise turning force which is transmitted to the flip 14 causing it to be urged towards the main body 12 .",
"Since the upper edge of the flip 14 abuts the chin 26 of the radiotelephone 10 at a horizontal, a standing torque or detent torque is set up on the flip 14 .",
"In this way, in the closed position the flip 14 offers a certain amount of in-built resistance to being opened and prevents it from having a sloppy feel.",
"Conversely, with the flip 14 in the open position the configuration of the leaf spring 44 and the hinge shaft 42 is as illustrated in FIG. 7 b .",
"Opening of the flip 14 is facilitated by formations on the side edges and the rear of the flip.",
"In this open position the flip 14 has travelled through 160° and the spatulate ends 66 of the leaf springs 44 have reversed orientation and press against the other pair of shoulders of the camming surface 58 .",
"Again, the spatulate ends 66 do not lie on the major faces 60 and accordingly the leaf springs 44 now transmit an anti-clockwise turning force on the flip.",
"The flip 14 however is prevented from moving to adopt this position by a stop feature 52 / 84 .",
"The stop feature is shown in FIG. 8 and comprises the raised lug 56 on the collar 52 of the hinge shaft which engages a short axial lip 84 spanning two adjacent rails extending from the internal wall of the flip hinge tube 39 .",
"When the flip is moved to the open position, the axial lip 84 approaches the lug 56 and at 160° opening catches against it.",
"Due to the in-built detent torque of the springs 44 and camming surface 58 in this position, the flip 14 is biased in the open position.",
"The stop feature 52 / 84 is designed to be positive enough to provide sufficient support for the flip 14 when it is pressed against a user's ear during a call.",
"However, a combination of the tolerances of the components and the inherent elasticity of the hinge materials allows the lug 56 to ride over the lip 84 if excessive force is applied to the flip.",
"For example, if the flip 14 is in the open condition and someone inadvertently sits on the phone 10 , the lug 56 overrides the axial lip 84 and the flip 14 can travel passed the 160° opening angle without breaking the flip 14 , hinge 40 or stop feature 52 / 84 .",
"In this event, the leaf spring 44 indexes rounds to the stable major face 60 .",
"To return the flip, the user holding the main body and flip manually snaps the lug 56 back over the axial lip 84 .",
"As is apparent, this override property provides a beneficial safety feature for the radiotelephone 10 against damage.",
"It will be readily understood that alternative arrangements to those described above with reference to the specific embodiment can be made within the inventive concept as defined in the appended claims.",
"For example the resilient means, instead of being a leaf spring could be an elastomeric composite.",
"Each feature disclosed in this specification (which term includes the claims) and/or shown in the drawings may be incorporated in the invention independently of other disclosed and/or illustrated features.",
"The appended abstract as filed herewith is included in the specification by reference."
] |
BACKGROUND
[0001] Commercial food manufacturers strive to deliver improved food products to the consumer to meet a wide variety of consumer preferences. One such consumer preference is the desire to increase the nutritional value of regularly consumed food products such as breads, rolls, buns and other bakery products. The desire for highly nutritive food products must also be balanced by the consumer's preference for organoleptically appealing food products. The commercial food manufacturer is faced with the challenge of providing highly nutritive food products, such as bakery products, which retain acceptable organoleptic properties such as taste, texture, and appearance, and especially those products that can retain the desired organoleptic properties during the shelf life of the food product.
[0002] The nutritional value of a food product, therefore, is something that the commercial food manufacturer would want to promote to the consumer through labeling, advertising, and the like. As with other aspects of food labeling, the U.S. Food and Drug Administration (FDA) has issued regulations regarding the health claims that can be made regarding a food product. Among these regulations are regulations that are specific to the level of nutrients delivered by the food product in order to support the claimed health benefit. In other words, in order for a food product to carry an FDA-approved health claim on the product label or other promotional materials, the food product must consistently deliver a nutrient or a combination of nutrients at defined levels per serving.
[0003] Bread is a dietary staple to which many nutritional ingredients have been added. Currently, there are commercially available whole wheat breads meeting the FDA heart health claim requirements regarding whole grain content. Whole wheat contains wheat gluten, and therefore tends to have a less adverse effect on the quality of the bread, particularly on the specific volume and texture of the bread, than non-wheat ingredients. There are also 9- and 12-grain breads, and breads designed to deliver specific nutrients or supplements to meet specific dietary needs, and other similar breads. Although these breads contain nutritive ingredients, the level of a specific nutrient, such as protein or fiber, provided per serving generally falls short of the levels required by the FDA regulations for specific health claim labeling. This is because the high level of nutrients required for making an FDA health claim on a product typically has an adverse effect on the quality of the bakery product, particularly on the specific volume and texture of the bakery product.
[0004] Dietary fiber is a nutrient that food manufacturers strive to increase in food products, but which typically has deleterious effects on the food product. Dietary fiber is generally divided into two categories, soluble and insoluble, based on the solubility of the fiber in water at room temperature. Increasing soluble fiber intake improves digestion by providing nutrients to intestinal flora and/or lowering cholesterol. Insoluble fiber promotes overall health by providing indigestible bulk to food products.
[0005] However, the addition of high levels of fiber to food products is known to adversely affect the organoleptic properties of food products. High fiber food products can have a dry, tough, chewy, or dense texture, making them less appealing to consumers. In fact, the level of dietary fiber needed to meet an FDA fiber claim in a bakery product is often so high that a dough containing the requisite amount of fiber is simply unprocessable on a commercial manufacturing line, usually because the dough is either too stiff or too plastic as a result of the fiber ingredient added. Therefore, not only are high fiber products difficult to prepare from an organoleptic standpoint, they are difficult to prepare from a commercial manufacturing standpoint as well.
[0006] The commercial food manufacturer is therefore faced with the challenge of providing high fiber bakery products that retain acceptable organoleptic properties such as taste, texture, and appearance, and that can readily be made using conventional commercial manufacturing equipment and processes.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to a high fiber blend for making food products. The high fiber blend replaces part of the flour used to make a dough, thereby providing a high level of fiber to the food product made from the dough. The blend, which includes a stiffening agent and a plasticizing agent, provides a high level of fiber without substantially affecting the rheological properties of the dough. Therefore, the blend allows high fiber food products to be made using conventional commercial manufacturing equipment and processes. The blend can be used to produce organoleptically pleasing food products that contain sufficient amounts of fiber to meet FDA requirements for fiber-related health claims.
[0008] The present invention is also directed to a method of making a high fiber blend for food products. This method involves measuring a rheological property, such as peak resistance, of a stiffening agent and a plasticizing agent. The stiffening agent and plasticizing agent are then combined to create the high fiber blend. The relative amounts of stiffening agent and plasticizing agent are selected such that the resulting blend is able to provide a high level of fiber to a food product, without substantially affecting the theological properties of the dough from which the food product is made.
[0009] The present invention is also directed to a premix made of the high fiber blend and vital wheat gluten. The premix is suitable for use in a one-to-one replacement on a weight percent basis of some of the flour in the dough formula.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a Farinograph® curve of a control dough made with 100% flour at 65% absorption.
[0011] FIG. 2 is a Farinograph® curve of a dough made with 10% aleurone and 90% flour at 65% absorption.
[0012] FIG. 3 is a Farinograph® curve of a dough made with 10% inulin and 90% flour at 65% absorption.
[0013] FIG. 4 is a Farinograph® curve of a dough made with 25% premix and 75% flour at 65% absorption, where the premix was a rheologically balanced blend of aleurone, inulin, and VWG.
[0014] FIG. 5 is a Farinograph® curve of a dough made with 18% premix and 82% flour at 65% absorption, where the premix was a non-balanced blend of aleurone and VWG.
[0015] FIG. 6 is a Farinograph® curve of a dough made with 13% premix and 87% flour at 65% absorption, where the premix was a non-balanced blend of inulin and VWG.
[0016] FIG. 7 is a Farinograph® curve of a dough made with 10% premix and 90% flour at 65% absorption, where the premix was a theologically balanced blend of cottonseed fiber, inulin, and VWG.
[0017] FIG. 8 is a Farinograph® curve of a dough made with 9.2% premix and 90.8% flour at 65% absorption, where the premix was a non-balanced blend of cottonseed fiber and VWG.
[0018] FIG. 9 is a Farinograph® curve of a dough made with 10% polydextrose and 90% flour at 69% absorption.
[0019] FIG. 10 is a Farinograph® curve of a dough made with 10% psyllium husk powder and 90% flour at 69% absorption.
[0020] FIG. 11 is a Farinograph® curve of a dough made with 10% premix and 90% flour at 69% absorption, where the premix was a rheologically balanced blend of psyllium, polydextrose, and VWG.
[0021] FIG. 12 is a Farinograph® curve of a dough made with 22% premix and 78% flour at 69% absorption, where the premix was a rheologically balanced blend of psyllium, polydextrose, and VWG.
DETAILED DESCRIPTION
[0022] The present invention is directed to a high fiber blend that provides the desired level of dietary fiber to a food product, such as a bakery product, and that can be used in a commercial manufacturing process without requiring significant adjustment of the water content or other ingredients of the product because of the high fiber content. The bakery products made with the high fiber blend of the present invention have desirable organoleptic properties, such as specific volume and texture, similar to those properties of a conventional bakery product that does not contain added fiber.
[0023] It has been surprisingly discovered that by using a combination of dietary fiber ingredients, the typical adverse effects of having a high level of fiber can be alleviated, resulting in a product that is readily made using a conventional commercial manufacturing process. Products made in accordance with the present invention have specific volumes and textures that are similar to the specific volume and texture of a control product made without the added high fiber blend. Preferably, product made in accordance with the present invention have specific volumes of at least about 4.0 cc/g or higher, and include high levels of fiber, preferably about 5% by weight or higher.
[0024] In addition, the method of the present invention can be used to significantly increase the amount of fiber that can be added to a product formulation substantially without adverse effects on the processing of the product or the finished product attributes. The method of the present invention also enables the use of fiber ingredients that previously could not be used or could only be used in limited amounts due to their drastic adverse effects on dough rheology.
[0025] The addition of fiber to replace a portion of the flour content in a bakery product formula to achieve a certain fiber level in the product can have numerous deleterious effects on the dough and the final product. First, because the fiber is used to replace a portion of the flour, the total gluten level drops, since wheat flour naturally contains gluten. Second, since there are many different types of dietary fiber available for use in food products, it is difficult to predict the effects a certain type of fiber may have on the dough or on the final product.
[0026] These problems have to date required commercial manufacturers to make numerous significant changes in product formulations and processing in order to make bakery products that meet the FDA's current requirements for dietary fiber sources, and that are comparable to conventional bakery products. Even with these changes, there is a continuing need for fiber ingredients that can be added to a dough formulation at high levels to provide the FDA's current requirements for dietary fiber, but without substantial changes to the dough's rheological properties, and therefore, the processing parameters of the high-fiber containing dough.
[0027] When fiber ingredients are added to dough, major issues with processing and final product quality can arise. Due to the hygroscopic nature of fiber, mixing times often must be extended to assure the fibers are hydrated and incorporated into the dough. Additionally, since the fiber is usually non-functional with respect to gas holding ability, the dough will not be able to retain as much gas, so the final product specific volumes may be lower and product textures may be more dense as compared to control products. If the dough becomes significantly more stiff or more flowable upon the addition of one or more fiber ingredients, it may be difficult to sheet the dough and form it prior to baking. Processing equipment used to divide the dough into portions (i.e., dough dividers) is often affected by dough rheology, and weight changes may occur leading to improperly sized and weighed product. Bake times can also be affected since the water in the dough is bound differently due to the incorporation of the fiber ingredient. Since bake times can be affected, final product quality parameters such as browning can also be adversely affected.
[0028] Commercially, when a fiber ingredient is incorporated into a dough, it is often necessary to add back the functional protein (i.e., gluten) that is removed, as will be further described below, adding an additional expense and variation to the formulation. Additionally, to counteract the change in rheology caused by the addition of the fiber, water is either added or removed from the dough formula. With fibers that have radical effects on rheology or for those used at high levels (or both), a large change in water level is required. This water level adjustment is usually determined experimentally with a control formula dough on a commercial scale. In the case where excess water is added, it takes longer to bake the water out of the dough to convert it to bread during the baking process, necessitating changes in bake times and/or temperatures. Conversely, when water is removed, bake times may be reduced. However, for some systems, if the negative effects of the fiber on dough rheology and gas holding properties is too severe, even adjustments as described herein will be insufficient to produce a processable dough and hence a good quality final product.
[0029] By using the product and process of the present invention, it is now possible to utilize, on a commercial scale, a significant number of fiber sources, at relatively high levels, without significantly adversely impacting the theological properties of the dough. As such, commercial food manufacturers can attain the desired fiber levels in bakery products, without the serious adverse effects on dough rheology and processing as previously encountered. Preferably, commercial food manufacturers can use the present invention to make high fiber products without needing to change the water level in the products during manufacture, as compared to a control product.
[0030] There are numerous fiber sources suitable for use in food and bakery products. As those skilled in the art will understand, the teachings of the present invention can be used with virtually any fiber source that is suitable for consumption, at levels that meet or exceed current US FDA requirements for being a “good source of fiber” or an “excellent source of fiber” in a bakery product.
[0031] Suitable fibers include, but are not limited to, the following: saccharides, such as mono-, di-, oligo-, and polysaccharides in general; cottonseed, soy, sunflower and other oilseed fibers; wheat bran, oat bran, cereal aleurone and other cereal fibers; derivatized and native celluloses, xylans, pentosans, hemicelluloses, gums, such as gum Arabic, pectin, guar, carageenan, xanthan, and locust bean gum, and other non-starchy polysaccharides; alginates; inulin and fructooligosaccharides (FOS), including fungal FOS; polydextrose; arabinogalactan; arabinoxylan; barley beta fiber; psyllium; the USDA's “Z-trim” fat substitute and other fiber-based fat substitutes; retrograded, resistant, or slow degrading starches; glucans, such as beta-glucan and fungal beta glucan, and including encapsulated beta-glucan; chitin; chitosan; citrus fiber; corn fiber; seed based fibers; mannans; sugar beet fiber; malt flour; cocoa hull fiber; spent brewer's grains; malt sprouts, flax meal; canola meal; tapioca fiber, rice hull fiber; barley straw flour; fermented wheat fiber; and combinations thereof. The fiber sources can be in either powdered or particulate form.
[0032] As used herein, the expressions “control product” or “conventional product” shall be used to refer to products to which no additional fiber ingredients are added, so that the flour content of the control or conventional product is considered 100 Bakers' percent. All percentages are given as weight percent unless indicated otherwise.
[0033] As used herein, the term “bakery product” shall refer to any product incorporating flour, including, but not limited to, breads, rolls, buns, bagels, pretzels, pizza or similar crusts, tortillas, pita bread, foccacia, English muffins, donuts and “cakey” brownies, which are baked or otherwise processed with heat to set the finished product structure.
[0000] Dough Properties
[0034] The properties of bread and other bakery products are predominantly determined by the properties of the dough. The dough properties, in turn, are determined by the dough ingredients and by how the dough is processed. The most basic dough ingredients are wheat flour, water, salt, and a leavening system, such as yeast, chemical leavening agents, or a combination of both yeast and chemical leavening agents.
[0035] Upon mixing water with the flour and the leavening system, the flour particles become hydrated, and the shear forces applied by mixing cause wheat gluten protein fibrils from the flour particles to interact with each other and ultimately form a continuous gluten matrix.
[0036] Furthermore, as the dough is mixed, air is incorporated in the dough, creating air cells throughout the dough. When carbon dioxide gas is generated by the leavening reaction in the dough, the carbon dioxide first goes into solution. As the water in the dough becomes saturated with carbon dioxide, carbon dioxide being generated by the leavening migrates into the air cells in the dough. The number and stability of the air cells in the dough is determined by the quality of the gluten matrix and the number of air bubbles initially included.
[0037] A well-developed wheat gluten matrix results in a dough that can retain the carbon dioxide generated by the leavening system, and therefore deliver the desired specific volume in the final baked product.
[0038] Replacing some of the flour and adding non-glutenaceous ingredients, such as fiber, to the dough interferes with the ability of the gluten to form a continuous matrix during mixing. The non-glutenaceous ingredients may compete for the moisture in the dough, thereby hindering the formation of the gluten matrix. In addition, the non-glutenaceous ingredients may occupy space in the dough and physically limit the gluten-gluten interactions required to form the gluten matrix. Furthermore, the non-glutenaceous ingredients may serve as air cell nucleation sites and may cause large air pockets to form in the dough. Gas generated by the leavening action will preferentially migrate to the air pockets rather than remaining distributed in the smaller air cells that are more evenly dispersed through the dough, creating an undesirable texture in the final bakery product. Therefore, the advantages of adding non-glutenaceous ingredients to the bread, such as fiber ingredients, must be balanced with the deleterious effects such ingredients may have on the gluten matrix, the overall dough structure, and the resulting baked product quality.
[0039] Gluten is a naturally occurring protein in wheat flour. By reducing the flour content, the gluten content of the dough is also reduced. Adding gluten to the dough formula compensates for the loss of gluten from flour and provides the necessary structure and stiffness to the dough. However, adding too much gluten results in a highly elastic bakery product that does not demonstrate the desired properties. Generally, when wheat flour is replaced with a non-glutenaceous ingredient, vital wheat gluten must be added in quantities necessary to keep the total gluten content (i.e., the gluten native in the wheat flour and the added vital wheat gluten) of the product constant. In cases where the vital wheat gluten is not as functional (i.e., able to retain leavening gas) as the native gluten in wheat flour, it is necessary to add somewhat elevated levels of wheat gluten.
[0040] In accordance with the present invention, wheat gluten is added to the formula to compensate for the gluten reduction concomitant with the flour reduction. Preferably, for every 1% by weight reduction of flour-based protein in the formula, between about 1% to about 2% by weight of vital wheat gluten is added to the formula.
[0041] The amount of gluten added must be balanced with the amount of fiber added, due to the non-glutenaceous behavior of fiber. Typically, dietary fiber sources have a high water absorption capacity. Insoluble fibers absorb the limited amount of water in a dough system, which stiffens or hardens the dough. Some highly soluble fibers can go into solution in the limited amount of water in the dough, thereby plasticizing the dough by effectively increasing the solvent level in the dough system. Other soluble fibers cannot go into solution as readily, and may end up actually stiffening the dough, rather than plasticizing it. These varying effects of the fiber on the dough are also reflected in the final product, which can suffer from the less than optimal dough rheology due to the added fiber ingredient. These variations also make the dough difficult to process commercially without major adjustments to the formula, for example, by adding more water, or to the processing conditions, such as mixing or line processing speeds.
[0042] In accordance with the present invention, a dough stiffening fiber ingredient is combined with a dough plasticizing fiber ingredient to prepare a dough that has rheological properties substantially similar to a control dough that does not contain added fiber. In some embodiments, a plurality of dough stiffening agents and/or dough plasticizing agents can be used.
[0043] To optimize the use of these fiber ingredients, the effects of a particular fiber ingredient on the dough's rheological properties are monitored to ensure that the water relationships (i.e., absorption) of the dough remains constant and within a processable range. By balancing the types of fiber ingredient used, the dough can be made, processed, and baked using the same manufacturing equipment and parameters as a conventional bread.
[0044] Rheological properties of dough products are usually measured by evaluating the viscoelastic properties of the dough. One instrument used to measure the viscoelastic property is the Farinograph® instrument, available from C.W. Brabender Instruments, Inc., 50 East Wesley Street, South Hackensack, N.J. The Farinograph® instrument measures the resistance of the dough to mechanical mixing. The resistance is recorded as a curve on a graph. The Farinograph® curve provides the useful information regarding the dough strength, mixing tolerance, and absorption (water holding) characteristics of the product being evaluated. The resistance is measured in Brabender units (BU).
[0045] As will be appreciated by those of skill in the art of commercial dough and bakery product manufacturing, the rheological properties of the dough must be consistent and must fall within certain parameters in order to be able to be successfully processed on an industrial processing line. Changing processing parameters to adjust for product variations is a time- and resource-consuming endeavor, and often requires significant line down-times in order to adjust and correct for processing variations. For example, when the amount of water or moisture-containing ingredients needs to be adjusted, the manufacturer needs to ensure that microbial safety standards are met in the processing facility as well as in the products being made.
[0046] The dough made in accordance with the present invention, containing the high fiber blend of the present invention, does not require the addition of water or a significant adjustment of processing conditions as compared to a control dough in order to be made into a suitable dough and bakery product.
[0047] The high fiber blend product of the present invention is designed to enable a commercial manufacturer to use the fiber blend in a one-to-one replacement of some of the flour to make a high fiber bakery product without requiring the manufacturer to adjust the water, plasticizer or stiffener content, or to significantly alter the processing parameters typically associated with such replacement. As used herein, the expression “one-to-one replacement” shall be defined as reducing the flour in the dough formula by a certain amount and replacing it with the same amount, by weight percent, of the fiber blend. This permits the commercial bakery product manufacturer to make bakery products with any desired level of added fiber, preferably up to about 40%, more preferably between about 5% and 35%, and even more preferably between about 15% and 25%, without requiring significant changes in the manufacturing process or the product formula.
[0048] The high fiber blend product of the present invention utilizes a combination of water absorption characteristics of various fiber ingredients to balance out the overall effects of the fiber blend on the rheological properties of the dough. By balancing absorption characteristics, virtually any fiber ingredient can be used in a fiber blend product in accordance with the present invention.
[0049] To make a rheologically balanced high fiber blend product in accordance with the present invention, the water absorption characteristics of the desired fiber ingredients must be determined. The present invention is further directed to a method for determining the water absorption characteristics of the fiber ingredient and balancing those characteristics with another fiber ingredient having different water absorption characteristics. In accordance with the present invention, a method based on the Farinograph® instrument is used to determine the water absorption characteristics of the desired fiber ingredient. This method is described in Example 1 below.
EXAMPLE 1
[0050] To design a theologically balanced high fiber premix for breads and similar products, it is first necessary to measure the effects of the various fiber ingredients on dough rheology. This is accomplished with the Farinograph® instrument. By replacing 10% of the flour in a flour-water dough with the fiber ingredient and maintaining absorption at a constant level, it is possible to determine how much the rheology is affected by the various fibers relative to each other and relative to the Farinograph® curve of a reference flour ( FIG. 1 ). Some fibers will yield doughs with higher peak Brabender Unit (BU) values ( FIG. 2 ) than the reference flour and will hence stiffen the dough. Others yield lower peak BU values and hence plasticize the dough ( FIG. 3 ).
[0000] Farinograph® Instrument Method
[0051] The absorption of the flour is determined using 480 g of dough. The flour moisture is on an “as is” basis. The ingredients are dry blended for 1 minute with the water being added in its entirety within 30 seconds.
[0052] Farinograph® instrument conditions:
[0053] 300 gram bowl
[0054] Bowl temperature: 77° F.
[0055] Water temperature: 70° F.
[0056] Farinograph® instrument rpm: 63 rpm
[0057] Once the absorption has been established, as shown in FIG. 1 , where the curve is balanced on the 500 BU line, 10% of the flour is replaced with the fiber ingredient of interest. The amount of water is kept constant and the Farinograph(l instrument is run until a peak has been determined. The absorption of the flour in these examples was 65%.
Baker's Percent Control: Artisan bread flour 100 Water (65% abs) 65 Samples: Artisan bread flour 90 Sample Fiber Ingredient 10 Water 65
[0058] The theological effect information gathered by this method, as shown in Table 1, enables the formulation of theologically balanced high fiber premixes in accordance with the present invention. In general, high fiber blends and premixes made in accordance with the present invention will have peak resistance values of between about 100 BU greater than the control BU value and about 100 BU less than the control BU value. Preferably, high fiber blends and premixes made in accordance with the present invention will have peak resistance values of between about 50 BU greater than the control BU value and about 50 BU less than the control BU value. More preferably, high fiber blends and premixes made in accordance with the present invention will have peak resistance values of between about 25 BU greater than the control BU value and about 25 BU less than the control BU value.
TABLE 1 Farinograph ® Instrument Parameters for High Fiber Ingredients in Combination with Flour (10:90) Peak Width Peak Time Arrival Departure Stability MTI** Ingredient Peak BU (BU) (min) (min) (min) (Min) (BU) Arabinogalactan 1 230 50 70 53 94* 41 10 F97 Inulin 2 260 40 40.5 31.5 60 28.5 20 Inulin-Standard 3 270 50 38 29 45* 16 10 Polydextrose 4 270 50 40 30 54* 24 10 Sugar 5 330 60 8.5 3 30.5 27.5 20 Gum Arabic 6 430 60 26.5 22.5 37.5 15 20 Inulin-LCHT 7 450 100 16 11.5 27.5 16 30 Actistar ™ RT 8 500 120 8.5 1.5 20 18.5 40 Flour 9 (Control) 510 100 10.5 3 20 17 20 Cottonseed Fiber 10 550 100 8 1.5 24.5 23 20 Soy Fiber (SF) 11 590 110 8 1 22.5 21.5 20 Aleurone 12 630 100 5.5 2 12 10 40 Joshi (Corn Bran) 13 700 120 5.5 1.75 9.5 7.75 90 Oat fiber 14 740 160 7.5 2.25 20 17.75 60 Soy Cotyledon fiber 5 880 190 8 3 27 24 20 Psyllium 16 >1000 *Longer curves would be necessary to find the actual departure times. **Farinograph ® Instrument Mixing Tolerance Index 1 Larex Inc., MN 2 Oliggo-Fiber ™ F97, Cargill, Inc., MN 3 Oliggo-Fiber ™ standard, Cargill, Inc., MN 4 Sta-Lit ® III 7, Tate and Lyle, IL 5 Granulated sugar, Cargill, Inc., MN 6 Nutraloid Arabic Spray Powder, TIC, MD 7 Oliggo-Fiber ™ LCHT, Cargill, Inc., MN 8 C*Actistar Actistar ™ RT (resistant starch), Cargill, Inc., MN 9 Cargill “Progressive Baker Artisan Bread Flour”, Cargill, Inc., MN 10 I7C, Just Fiber, NY 11 Soybean Hull Fiber, Fibred, MD 12 GrainWise ™ , Cargill, Inc., MN 13 MaizeWise ™ , Cargill, Inc., MN 14 Hesco, SD 15 Ingredient in development, Cargill, Inc., MN 16 Psyllium blond seed husk powder 40 mesh, BI Nutraceuticals, CA
[0059] To effectively replace flour, however, it is also necessary to supplement the premix with an amount of vital wheat gluten equaling the amount of protein lost by replacing the flour with a fiber ingredient.
[0060] For example, if a flour contains 12% protein, for every 10% of the flour replaced by a fiber ingredient, 1.2% of flour protein has been removed from the system. Since vital wheat gluten (VWG) is normally only about half as functional as the native gluten it replaces, it is added as a component of the premix at about double the level required to replace the removed flour protein to maintain constant functionality. The amount of VWG added can vary significantly, however, depending on the functionality of the flour protein replaced and the vital wheat gluten itself. The fiber ingredients (stiffening and plasticizing) are added to the premix formula at a level of 100% minus the gluten percentage in a ratio required to balance the total formula rheology.
[0061] To make a premix using the rheologically balanced high fiber blend, the final step is to identify the right blend of gluten, stiffening fiber and plasticizing fiber to yield a high fiber premix that does not significantly affect dough rheology when it replaces a portion of the flour in the formula. The VWG percentage in the premix and the total level of fibers are determined as described above. An approximate desired total dietary fiber (TDF) content of the finished bread is then chosen. A practical TDF content is one between the low end of a desired fiber level range (e.g., 10% of the US FDA's Recommended Daily Allowance or Daily Reference Value, or RDA/DRV—a good source of fiber) and the high end of the range (e.g., 20% of the RDA/DRV—an excellent source of fiber), with the current RDA/DRV for fiber being 25 grams, in the finished product to assure replacement levels of both the gluten and the fiber blend are optimal. When the RDA/DRV level is set, the corresponding flour replacement level is used to determine the ratio of the stiffening and plasticizing fibers in the premix. This is determined experimentally using the Farinograph® instrument method so that the water requirement of the original flour is duplicated, as shown in FIG. 4 .
[0000] Aleurone-Inulin Premix
[0062] In this example, the following high fiber blend in a premix form was determined to be suitable for use on a commercial scale.
Premix 1 Composition VWG 20% Aleurone 52% Inulin-Standard 28%
[0063] The total dietary fiber content of this premix is about 42%. To produce a. “good source of fiber”-containing bread, the manufacturer would replace 16% of the flour in the formula with this premix. To produce an “excellent source of fiber”-containing bread, the manufacturer would replace 34% of the flour in the formula with this premix.
EXAMPLE 1A
[0064] This example demonstrates the effects on rheology and quality of removing inulin or aleurone from the rheologically balanced high fiber blend described in Example 1. These non-balanced premixes clearly demonstrate the effects of the single fiber ingredient on the rheological properties of the dough.
Premix 1 Composition with Inulin Removed: VWG 18% Aleurone 82%
[0065] The total dietary fiber content of this premix is about 42%. To produce a “good source of fiber”-containing bread, 18% of the flour in the formula was replaced with this premix. The results are shown in FIG. 5 , which shows that the Farinograph® curve is significantly higher than the reference line at 500 BU.
Premix 1 Composition with Aleurone Removed: VWG 18% Inulin-Standard 82%
[0066] The total dietary fiber content of this premix is about 59%. To produce a “good source of fiber”-containing bread, 13% of the flour in the formula was replaced with this premix. The results are shown in FIG. 6 , which shows that the Farinograph® curve is significantly lower than the reference line at 500 BU.
[0067] Breads were baked using the rheologically balanced high fiber premix of the present invention and were compared to the non-balanced fiber premixes using the bread formula in Table 2 and the following processing procedures.
TABLE 2 Formulas for High Fiber Breads Baker's Ingredient Percent Wheat flour, enriched 1 100-value in Table 3 Premix See Table 3 HFCS 2 10.0 Soybean oil 3 2.0 Panalite ® SV 4 0.5 Salt 5 2.0 Dough Conditioner 6 1.5 Compressed yeast 7 4.0 Water 60.0 Total 180.0 1 Cargill “Progressive Baker Artisan Bread Flour”, Cargill, Inc., MN 2 IsoClear ™, Cargill, Inc., MN 3 Cargill Soybean Salad Oil (soybean oil with citric acid as preservative), Cargill, Inc., MN 4 ADM Arkady Panalite ® 50 SVK emulsifier, ADM, IL 5 Evaporated food grade salt, United Salt Corp., TX 6 S-500 conditioner, Puratos Corp., NJ 7 Eagle, Lallemand, Inc., Montreal, Canada
[0068] An approximately 1200 gram batch of dough was mixed in a Hobart mixer equipped with a McDuffey bowl for 1 minute on low speed and 8 minutes on medium speed. 480 grams of dough were scaled and placed in a Farinograph® instrument. Brabender units of this dough were recorded. The remainder of the dough was then allowed to rest for 10 minutes and four 160 gram pieces of dough were scaled. The dough was then allowed another 10 minute rest before the dough was sheeted and rolled with a Moline Bread Molder (final gap setting=1.5, pressure board setting=6). The dough was allowed to proof for 50 minutes and then baked 16 minutes at 400° F. Specific volume was determined by dividing the volume of the loaves by their weight after cooling for 1 hour. The following results (shown in Table 3) were obtained:
TABLE 3 Dough Rheology and Bake Data for Rheologically Balanced and Unbalanced Dough Systems Brabender High Fiber Bread Flour Units of Specific Volume Premix Composition Replacement Bread Dough (cc/g) of (see formulas above) Level (%) After Mixing Finished Bread Control (no premix) 0 510 6.4 aleurone, inulin, VWG 1 16 500 5.5 aleurone, inulin, VWG 34 520 4.6 aleurone, VWG 18 700 5.4 aleurone, VWG 34 >700 <3.0 inulin,VWG 13 380 5.1 inulin, VWG >13 could not n.a. process 1 Vital Wheat Gluten (made in Poland), Cargill, Inc., MN
[0069] As can been seen from the data in Table 3, the rheologically balanced high fiber blend of the present invention resulted in a dough that had substantially the same rheology as a control dough and therefore did not require significant adjustments to the water content of the formula or to the processing parameters, and resulted in a baked product having a desirable specific volume even at the “excellent source of fiber” level (34% flour replacement). The individual fiber ingredients, used alone in the dough formulation, did not result in acceptable doughs. Rheology of these doughs was affected dramatically with Brabender units of mixed doughs changing more than 100 than the control in all cases. This led to severe processing issues in some cases and made processing of the dough into a finished product impossible in one case (i.e., the last data set in Table 3 for the composition containing only inulin and VWG at levels greater than 13% flour replacement).
EXAMPLE 2
Cottonseed Fiber-Inulin Premix Composition
[0070] Using the methodology described above, another premix composition in accordance with the present invention was formulated as follows:
Premix 2 Composition VWG 25% Cottonseed Fiber 47% Inulin-Standard 28%
[0071] The total dietary fiber content of this premix is about 61%. To produce a “good source of fiber”-containing bread, a manufacturer would replace 10% of the flour in the formula with this premix. To produce an “excellent source of fiber”-containing bread, the manufacturer would replace 20% of the flour in the formula with this premix. FIG. 7 shows the Farinograph® curve of a dough made with 10% of this premix and 90% flour at 65% absorption. As can be seen in FIG. 7 , the dough made with this rheologically balanced premix has the desired Farinograph® curve at 500 BU.
Premix 2 Composition with Inulin Removed VWG 28% Cottonseed 72%
[0072] The total dietary fiber of this premix is 61%. To produce a “good source of fiber”-containing bread, the manufacturer would replace 9.2% of the flour in the formula with this premix. To produce an “excellent source of fiber”-containing bread, the manufacturer would replace 18.4% of the flour in the formula with this premix. FIG. 8 shows the Farinograph® curve of a dough made with 9.2% of this premix and 90.8% at 65% absorption. As seen in FIG. 8 , the dough made with this non-balanced premix at a level needed to produce a “good source of fiber”-containing bread was not theologically acceptable.
[0073] The results for the premix composition with the cottonseed removed are shown in FIG. 6 described above.
[0074] Bread was prepared with these theologically balanced and non-balanced premixes using the general formula and procedures describes in Example 1A. Dough rheology and bake data for these evaluations is summarized in Table 4.
TABLE 4 Dough Rheology and Bake Data for Rheologically Balanced and Unbalanced Dough Systems (Cottonseed, inulin, VWG) Brabender High Fiber Bread Flour Units of Specific Volume Premix Composition Replacement Bread Dough (cc/g) of Finished (see formulas above) Level (%) After Mixing Bread Control (no premix) 0 480 6.3 Cottonseed fiber, 10 480 5.8 inulin, VWG Cottonseed fiber, 20 450 6.0 inulin, VWG Cottonseed fiber, 9.2 560 6.2 VWG Cottonseed fiber, 18.4 650 5.3 VWG Inulin, VWG 13 380 5.1 Inulin, VWG >13 could not n.a. process
[0075] As seen in Table 4, this rheologically balanced high fiber blend premix resulted in dough products that had nearly identical Farinograph® instrument data as the control product, and produced bread products with substantially similar specific volumes as that control product. The non-balanced premixes resulted in dough products that would require a substantial amount of processing adjustment in order to be commercially feasible.
EXAMPLE 3
Polydextrose-Psyllium Premix Composition
[0076] In this example, two fiber ingredients with radical effects on dough rheology were chosen to develop a theologically balanced high fiber premix. Polydextrose has a very strong plasticizing effect, while psyllium husk powder has a very strong stiffening effect, as shown in FIGS. 9 and 10 described below. In comparison, the Farinograph® curve of a control flour-water dough at 69% absorption would balance on the 500 BU line.
[0077] FIG. 9 shows a Farinograph(& curve of a dough made with 10% polydextrose and 90% flour at 69% absorption. As seen in this Figure, the use of polydextrose results in a Farinograph® curve that is substantially lower than the reference line at 500 BU. This dough was soup-like in consistency.
[0078] FIG. 10 shows a Farinograph® curve of a dough made with 10% psyllium husk powder and 90% flour at 69% absorption. As seen in this Figure, the use of psyllium husk powder results in a Farinograph(& curve that is significantly greater than the reference line at 500 BU. This dough was very hard and dry.
[0079] Consequently, using either of these fibers as the sole source of fiber in a high fiber bread formula would cause very significant rheology issues.
[0080] The following premix composed of psyllium, polydextrose and gluten was developed using the procedure described in Example 1.
Premix 3 Composition VWG 20% Psyllium Husk Powder 15% Polydextrose 65%
[0081] The total dietary fiber of the premix is about 72%. To produce a “good source of fiber”-containing bread, the manufacturer would replace 10% of the flour in the formula with this premix. To produce an “excellent source of fiber”-containing bread, the manufacturer would replace 22% of the flour in the formula with this premix.
[0082] FIG. 11 shows a Farinograph® curve of a dough made with 10% of the VWG/Psyllium/Polydextrose premix and 90% flour at 69% absorption. FIG. 12 shows a Farinograph® curve of a dough made with 22% of the VWG/Psyllium/Polydextrose premix and 78% flour at 69% absorption. As seen in these figures, despite the drastic adverse effects on dough rheology of the individual fiber components, by using the rheologically balanced high fiber blend premix of the present invention, a processable dough rheology can be achieved, with a Farinograph® curve near the 500 BU reference line.
[0083] Bread was produced with this premix using the general formula and procedures described in Example 1A. Dough rheology and bake data for these evaluations are contained in Table 5.
TABLE 5 Dough Rheology and Bake Data for Balanced Psyllium Husk Powder, Polydextrose, VWG Dough Systems High Fiber Bread Flour Brabender Units Specific Volume Premix Composition Replacement Of Bread Dough (cc/g) of Finished (see formula above) Level (%) After Mixing Bread Control (no premix) 0 460 6.45 Psyllium, 10 470 6.16 polydextrose, VWG Psyllium, 22 450 5.09 polydextrose, VWG
[0084] In this example, due to the drastic effects on dough rheology caused by each of psyllium and polydextrose individually, a bread dough was not prepared using just one of these ingredients as the fiber source due to anticipated damage to the processing equipment and overall lack of processability.
[0085] As can be seen in Table 5, even though psyllium and polydextrose, as individual fiber ingredients, have significant adverse effects on the dough rheology, when they are combined to make a rheologically balanced high fiber blend premix of the present invention, they can be used to make a dough product having processing attributes that are substantially the same as a control product, and final product attributes that are quite suitable for conventional bakery products.
[0086] Although the foregoing specification and examples fully disclose and enable the present invention, they are not intended to limit the scope of the invention, which is defined by the claims appended hereto. | The present invention is a high fiber blend which includes a stiffening agent and a plasiticizing agent. The blend replaces part of the flour in a dough without substantially affecting the dough's rheological properties. High fiber food products can then be made from the dough, using conventional commercial manufacturing equipment and processes. The blend can be used to produce food products that meet FDA requirements for fiber-related health claims. The present invention is also a method of making the high fiber blend. This method involves measuring a rheological property of the stiffening agent and the plasticizing agent. The stiffening agent and plasticizing agent are then combined, in amounts that will allow the resulting blend to provide a high level of fiber to a food product without substantially affecting the rheological properties of the dough. | Identify and summarize the most critical technical features from the given patent document. | [
"BACKGROUND [0001] Commercial food manufacturers strive to deliver improved food products to the consumer to meet a wide variety of consumer preferences.",
"One such consumer preference is the desire to increase the nutritional value of regularly consumed food products such as breads, rolls, buns and other bakery products.",
"The desire for highly nutritive food products must also be balanced by the consumer's preference for organoleptically appealing food products.",
"The commercial food manufacturer is faced with the challenge of providing highly nutritive food products, such as bakery products, which retain acceptable organoleptic properties such as taste, texture, and appearance, and especially those products that can retain the desired organoleptic properties during the shelf life of the food product.",
"[0002] The nutritional value of a food product, therefore, is something that the commercial food manufacturer would want to promote to the consumer through labeling, advertising, and the like.",
"As with other aspects of food labeling, the U.S. Food and Drug Administration (FDA) has issued regulations regarding the health claims that can be made regarding a food product.",
"Among these regulations are regulations that are specific to the level of nutrients delivered by the food product in order to support the claimed health benefit.",
"In other words, in order for a food product to carry an FDA-approved health claim on the product label or other promotional materials, the food product must consistently deliver a nutrient or a combination of nutrients at defined levels per serving.",
"[0003] Bread is a dietary staple to which many nutritional ingredients have been added.",
"Currently, there are commercially available whole wheat breads meeting the FDA heart health claim requirements regarding whole grain content.",
"Whole wheat contains wheat gluten, and therefore tends to have a less adverse effect on the quality of the bread, particularly on the specific volume and texture of the bread, than non-wheat ingredients.",
"There are also 9- and 12-grain breads, and breads designed to deliver specific nutrients or supplements to meet specific dietary needs, and other similar breads.",
"Although these breads contain nutritive ingredients, the level of a specific nutrient, such as protein or fiber, provided per serving generally falls short of the levels required by the FDA regulations for specific health claim labeling.",
"This is because the high level of nutrients required for making an FDA health claim on a product typically has an adverse effect on the quality of the bakery product, particularly on the specific volume and texture of the bakery product.",
"[0004] Dietary fiber is a nutrient that food manufacturers strive to increase in food products, but which typically has deleterious effects on the food product.",
"Dietary fiber is generally divided into two categories, soluble and insoluble, based on the solubility of the fiber in water at room temperature.",
"Increasing soluble fiber intake improves digestion by providing nutrients to intestinal flora and/or lowering cholesterol.",
"Insoluble fiber promotes overall health by providing indigestible bulk to food products.",
"[0005] However, the addition of high levels of fiber to food products is known to adversely affect the organoleptic properties of food products.",
"High fiber food products can have a dry, tough, chewy, or dense texture, making them less appealing to consumers.",
"In fact, the level of dietary fiber needed to meet an FDA fiber claim in a bakery product is often so high that a dough containing the requisite amount of fiber is simply unprocessable on a commercial manufacturing line, usually because the dough is either too stiff or too plastic as a result of the fiber ingredient added.",
"Therefore, not only are high fiber products difficult to prepare from an organoleptic standpoint, they are difficult to prepare from a commercial manufacturing standpoint as well.",
"[0006] The commercial food manufacturer is therefore faced with the challenge of providing high fiber bakery products that retain acceptable organoleptic properties such as taste, texture, and appearance, and that can readily be made using conventional commercial manufacturing equipment and processes.",
"SUMMARY OF THE INVENTION [0007] The present invention is directed to a high fiber blend for making food products.",
"The high fiber blend replaces part of the flour used to make a dough, thereby providing a high level of fiber to the food product made from the dough.",
"The blend, which includes a stiffening agent and a plasticizing agent, provides a high level of fiber without substantially affecting the rheological properties of the dough.",
"Therefore, the blend allows high fiber food products to be made using conventional commercial manufacturing equipment and processes.",
"The blend can be used to produce organoleptically pleasing food products that contain sufficient amounts of fiber to meet FDA requirements for fiber-related health claims.",
"[0008] The present invention is also directed to a method of making a high fiber blend for food products.",
"This method involves measuring a rheological property, such as peak resistance, of a stiffening agent and a plasticizing agent.",
"The stiffening agent and plasticizing agent are then combined to create the high fiber blend.",
"The relative amounts of stiffening agent and plasticizing agent are selected such that the resulting blend is able to provide a high level of fiber to a food product, without substantially affecting the theological properties of the dough from which the food product is made.",
"[0009] The present invention is also directed to a premix made of the high fiber blend and vital wheat gluten.",
"The premix is suitable for use in a one-to-one replacement on a weight percent basis of some of the flour in the dough formula.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0010] FIG. 1 is a Farinograph® curve of a control dough made with 100% flour at 65% absorption.",
"[0011] FIG. 2 is a Farinograph® curve of a dough made with 10% aleurone and 90% flour at 65% absorption.",
"[0012] FIG. 3 is a Farinograph® curve of a dough made with 10% inulin and 90% flour at 65% absorption.",
"[0013] FIG. 4 is a Farinograph® curve of a dough made with 25% premix and 75% flour at 65% absorption, where the premix was a rheologically balanced blend of aleurone, inulin, and VWG.",
"[0014] FIG. 5 is a Farinograph® curve of a dough made with 18% premix and 82% flour at 65% absorption, where the premix was a non-balanced blend of aleurone and VWG.",
"[0015] FIG. 6 is a Farinograph® curve of a dough made with 13% premix and 87% flour at 65% absorption, where the premix was a non-balanced blend of inulin and VWG.",
"[0016] FIG. 7 is a Farinograph® curve of a dough made with 10% premix and 90% flour at 65% absorption, where the premix was a theologically balanced blend of cottonseed fiber, inulin, and VWG.",
"[0017] FIG. 8 is a Farinograph® curve of a dough made with 9.2% premix and 90.8% flour at 65% absorption, where the premix was a non-balanced blend of cottonseed fiber and VWG.",
"[0018] FIG. 9 is a Farinograph® curve of a dough made with 10% polydextrose and 90% flour at 69% absorption.",
"[0019] FIG. 10 is a Farinograph® curve of a dough made with 10% psyllium husk powder and 90% flour at 69% absorption.",
"[0020] FIG. 11 is a Farinograph® curve of a dough made with 10% premix and 90% flour at 69% absorption, where the premix was a rheologically balanced blend of psyllium, polydextrose, and VWG.",
"[0021] FIG. 12 is a Farinograph® curve of a dough made with 22% premix and 78% flour at 69% absorption, where the premix was a rheologically balanced blend of psyllium, polydextrose, and VWG.",
"DETAILED DESCRIPTION [0022] The present invention is directed to a high fiber blend that provides the desired level of dietary fiber to a food product, such as a bakery product, and that can be used in a commercial manufacturing process without requiring significant adjustment of the water content or other ingredients of the product because of the high fiber content.",
"The bakery products made with the high fiber blend of the present invention have desirable organoleptic properties, such as specific volume and texture, similar to those properties of a conventional bakery product that does not contain added fiber.",
"[0023] It has been surprisingly discovered that by using a combination of dietary fiber ingredients, the typical adverse effects of having a high level of fiber can be alleviated, resulting in a product that is readily made using a conventional commercial manufacturing process.",
"Products made in accordance with the present invention have specific volumes and textures that are similar to the specific volume and texture of a control product made without the added high fiber blend.",
"Preferably, product made in accordance with the present invention have specific volumes of at least about 4.0 cc/g or higher, and include high levels of fiber, preferably about 5% by weight or higher.",
"[0024] In addition, the method of the present invention can be used to significantly increase the amount of fiber that can be added to a product formulation substantially without adverse effects on the processing of the product or the finished product attributes.",
"The method of the present invention also enables the use of fiber ingredients that previously could not be used or could only be used in limited amounts due to their drastic adverse effects on dough rheology.",
"[0025] The addition of fiber to replace a portion of the flour content in a bakery product formula to achieve a certain fiber level in the product can have numerous deleterious effects on the dough and the final product.",
"First, because the fiber is used to replace a portion of the flour, the total gluten level drops, since wheat flour naturally contains gluten.",
"Second, since there are many different types of dietary fiber available for use in food products, it is difficult to predict the effects a certain type of fiber may have on the dough or on the final product.",
"[0026] These problems have to date required commercial manufacturers to make numerous significant changes in product formulations and processing in order to make bakery products that meet the FDA's current requirements for dietary fiber sources, and that are comparable to conventional bakery products.",
"Even with these changes, there is a continuing need for fiber ingredients that can be added to a dough formulation at high levels to provide the FDA's current requirements for dietary fiber, but without substantial changes to the dough's rheological properties, and therefore, the processing parameters of the high-fiber containing dough.",
"[0027] When fiber ingredients are added to dough, major issues with processing and final product quality can arise.",
"Due to the hygroscopic nature of fiber, mixing times often must be extended to assure the fibers are hydrated and incorporated into the dough.",
"Additionally, since the fiber is usually non-functional with respect to gas holding ability, the dough will not be able to retain as much gas, so the final product specific volumes may be lower and product textures may be more dense as compared to control products.",
"If the dough becomes significantly more stiff or more flowable upon the addition of one or more fiber ingredients, it may be difficult to sheet the dough and form it prior to baking.",
"Processing equipment used to divide the dough into portions (i.e., dough dividers) is often affected by dough rheology, and weight changes may occur leading to improperly sized and weighed product.",
"Bake times can also be affected since the water in the dough is bound differently due to the incorporation of the fiber ingredient.",
"Since bake times can be affected, final product quality parameters such as browning can also be adversely affected.",
"[0028] Commercially, when a fiber ingredient is incorporated into a dough, it is often necessary to add back the functional protein (i.e., gluten) that is removed, as will be further described below, adding an additional expense and variation to the formulation.",
"Additionally, to counteract the change in rheology caused by the addition of the fiber, water is either added or removed from the dough formula.",
"With fibers that have radical effects on rheology or for those used at high levels (or both), a large change in water level is required.",
"This water level adjustment is usually determined experimentally with a control formula dough on a commercial scale.",
"In the case where excess water is added, it takes longer to bake the water out of the dough to convert it to bread during the baking process, necessitating changes in bake times and/or temperatures.",
"Conversely, when water is removed, bake times may be reduced.",
"However, for some systems, if the negative effects of the fiber on dough rheology and gas holding properties is too severe, even adjustments as described herein will be insufficient to produce a processable dough and hence a good quality final product.",
"[0029] By using the product and process of the present invention, it is now possible to utilize, on a commercial scale, a significant number of fiber sources, at relatively high levels, without significantly adversely impacting the theological properties of the dough.",
"As such, commercial food manufacturers can attain the desired fiber levels in bakery products, without the serious adverse effects on dough rheology and processing as previously encountered.",
"Preferably, commercial food manufacturers can use the present invention to make high fiber products without needing to change the water level in the products during manufacture, as compared to a control product.",
"[0030] There are numerous fiber sources suitable for use in food and bakery products.",
"As those skilled in the art will understand, the teachings of the present invention can be used with virtually any fiber source that is suitable for consumption, at levels that meet or exceed current US FDA requirements for being a “good source of fiber”",
"or an “excellent source of fiber”",
"in a bakery product.",
"[0031] Suitable fibers include, but are not limited to, the following: saccharides, such as mono-, di-, oligo-, and polysaccharides in general;",
"cottonseed, soy, sunflower and other oilseed fibers;",
"wheat bran, oat bran, cereal aleurone and other cereal fibers;",
"derivatized and native celluloses, xylans, pentosans, hemicelluloses, gums, such as gum Arabic, pectin, guar, carageenan, xanthan, and locust bean gum, and other non-starchy polysaccharides;",
"alginates;",
"inulin and fructooligosaccharides (FOS), including fungal FOS;",
"polydextrose;",
"arabinogalactan;",
"arabinoxylan;",
"barley beta fiber;",
"psyllium;",
"the USDA's “Z-trim”",
"fat substitute and other fiber-based fat substitutes;",
"retrograded, resistant, or slow degrading starches;",
"glucans, such as beta-glucan and fungal beta glucan, and including encapsulated beta-glucan;",
"chitin;",
"chitosan;",
"citrus fiber;",
"corn fiber;",
"seed based fibers;",
"mannans;",
"sugar beet fiber;",
"malt flour;",
"cocoa hull fiber;",
"spent brewer's grains;",
"malt sprouts, flax meal;",
"canola meal;",
"tapioca fiber, rice hull fiber;",
"barley straw flour;",
"fermented wheat fiber;",
"and combinations thereof.",
"The fiber sources can be in either powdered or particulate form.",
"[0032] As used herein, the expressions “control product”",
"or “conventional product”",
"shall be used to refer to products to which no additional fiber ingredients are added, so that the flour content of the control or conventional product is considered 100 Bakers'",
"percent.",
"All percentages are given as weight percent unless indicated otherwise.",
"[0033] As used herein, the term “bakery product”",
"shall refer to any product incorporating flour, including, but not limited to, breads, rolls, buns, bagels, pretzels, pizza or similar crusts, tortillas, pita bread, foccacia, English muffins, donuts and “cakey”",
"brownies, which are baked or otherwise processed with heat to set the finished product structure.",
"[0000] Dough Properties [0034] The properties of bread and other bakery products are predominantly determined by the properties of the dough.",
"The dough properties, in turn, are determined by the dough ingredients and by how the dough is processed.",
"The most basic dough ingredients are wheat flour, water, salt, and a leavening system, such as yeast, chemical leavening agents, or a combination of both yeast and chemical leavening agents.",
"[0035] Upon mixing water with the flour and the leavening system, the flour particles become hydrated, and the shear forces applied by mixing cause wheat gluten protein fibrils from the flour particles to interact with each other and ultimately form a continuous gluten matrix.",
"[0036] Furthermore, as the dough is mixed, air is incorporated in the dough, creating air cells throughout the dough.",
"When carbon dioxide gas is generated by the leavening reaction in the dough, the carbon dioxide first goes into solution.",
"As the water in the dough becomes saturated with carbon dioxide, carbon dioxide being generated by the leavening migrates into the air cells in the dough.",
"The number and stability of the air cells in the dough is determined by the quality of the gluten matrix and the number of air bubbles initially included.",
"[0037] A well-developed wheat gluten matrix results in a dough that can retain the carbon dioxide generated by the leavening system, and therefore deliver the desired specific volume in the final baked product.",
"[0038] Replacing some of the flour and adding non-glutenaceous ingredients, such as fiber, to the dough interferes with the ability of the gluten to form a continuous matrix during mixing.",
"The non-glutenaceous ingredients may compete for the moisture in the dough, thereby hindering the formation of the gluten matrix.",
"In addition, the non-glutenaceous ingredients may occupy space in the dough and physically limit the gluten-gluten interactions required to form the gluten matrix.",
"Furthermore, the non-glutenaceous ingredients may serve as air cell nucleation sites and may cause large air pockets to form in the dough.",
"Gas generated by the leavening action will preferentially migrate to the air pockets rather than remaining distributed in the smaller air cells that are more evenly dispersed through the dough, creating an undesirable texture in the final bakery product.",
"Therefore, the advantages of adding non-glutenaceous ingredients to the bread, such as fiber ingredients, must be balanced with the deleterious effects such ingredients may have on the gluten matrix, the overall dough structure, and the resulting baked product quality.",
"[0039] Gluten is a naturally occurring protein in wheat flour.",
"By reducing the flour content, the gluten content of the dough is also reduced.",
"Adding gluten to the dough formula compensates for the loss of gluten from flour and provides the necessary structure and stiffness to the dough.",
"However, adding too much gluten results in a highly elastic bakery product that does not demonstrate the desired properties.",
"Generally, when wheat flour is replaced with a non-glutenaceous ingredient, vital wheat gluten must be added in quantities necessary to keep the total gluten content (i.e., the gluten native in the wheat flour and the added vital wheat gluten) of the product constant.",
"In cases where the vital wheat gluten is not as functional (i.e., able to retain leavening gas) as the native gluten in wheat flour, it is necessary to add somewhat elevated levels of wheat gluten.",
"[0040] In accordance with the present invention, wheat gluten is added to the formula to compensate for the gluten reduction concomitant with the flour reduction.",
"Preferably, for every 1% by weight reduction of flour-based protein in the formula, between about 1% to about 2% by weight of vital wheat gluten is added to the formula.",
"[0041] The amount of gluten added must be balanced with the amount of fiber added, due to the non-glutenaceous behavior of fiber.",
"Typically, dietary fiber sources have a high water absorption capacity.",
"Insoluble fibers absorb the limited amount of water in a dough system, which stiffens or hardens the dough.",
"Some highly soluble fibers can go into solution in the limited amount of water in the dough, thereby plasticizing the dough by effectively increasing the solvent level in the dough system.",
"Other soluble fibers cannot go into solution as readily, and may end up actually stiffening the dough, rather than plasticizing it.",
"These varying effects of the fiber on the dough are also reflected in the final product, which can suffer from the less than optimal dough rheology due to the added fiber ingredient.",
"These variations also make the dough difficult to process commercially without major adjustments to the formula, for example, by adding more water, or to the processing conditions, such as mixing or line processing speeds.",
"[0042] In accordance with the present invention, a dough stiffening fiber ingredient is combined with a dough plasticizing fiber ingredient to prepare a dough that has rheological properties substantially similar to a control dough that does not contain added fiber.",
"In some embodiments, a plurality of dough stiffening agents and/or dough plasticizing agents can be used.",
"[0043] To optimize the use of these fiber ingredients, the effects of a particular fiber ingredient on the dough's rheological properties are monitored to ensure that the water relationships (i.e., absorption) of the dough remains constant and within a processable range.",
"By balancing the types of fiber ingredient used, the dough can be made, processed, and baked using the same manufacturing equipment and parameters as a conventional bread.",
"[0044] Rheological properties of dough products are usually measured by evaluating the viscoelastic properties of the dough.",
"One instrument used to measure the viscoelastic property is the Farinograph® instrument, available from C.W. Brabender Instruments, Inc., 50 East Wesley Street, South Hackensack, N.J. The Farinograph® instrument measures the resistance of the dough to mechanical mixing.",
"The resistance is recorded as a curve on a graph.",
"The Farinograph® curve provides the useful information regarding the dough strength, mixing tolerance, and absorption (water holding) characteristics of the product being evaluated.",
"The resistance is measured in Brabender units (BU).",
"[0045] As will be appreciated by those of skill in the art of commercial dough and bakery product manufacturing, the rheological properties of the dough must be consistent and must fall within certain parameters in order to be able to be successfully processed on an industrial processing line.",
"Changing processing parameters to adjust for product variations is a time- and resource-consuming endeavor, and often requires significant line down-times in order to adjust and correct for processing variations.",
"For example, when the amount of water or moisture-containing ingredients needs to be adjusted, the manufacturer needs to ensure that microbial safety standards are met in the processing facility as well as in the products being made.",
"[0046] The dough made in accordance with the present invention, containing the high fiber blend of the present invention, does not require the addition of water or a significant adjustment of processing conditions as compared to a control dough in order to be made into a suitable dough and bakery product.",
"[0047] The high fiber blend product of the present invention is designed to enable a commercial manufacturer to use the fiber blend in a one-to-one replacement of some of the flour to make a high fiber bakery product without requiring the manufacturer to adjust the water, plasticizer or stiffener content, or to significantly alter the processing parameters typically associated with such replacement.",
"As used herein, the expression “one-to-one replacement”",
"shall be defined as reducing the flour in the dough formula by a certain amount and replacing it with the same amount, by weight percent, of the fiber blend.",
"This permits the commercial bakery product manufacturer to make bakery products with any desired level of added fiber, preferably up to about 40%, more preferably between about 5% and 35%, and even more preferably between about 15% and 25%, without requiring significant changes in the manufacturing process or the product formula.",
"[0048] The high fiber blend product of the present invention utilizes a combination of water absorption characteristics of various fiber ingredients to balance out the overall effects of the fiber blend on the rheological properties of the dough.",
"By balancing absorption characteristics, virtually any fiber ingredient can be used in a fiber blend product in accordance with the present invention.",
"[0049] To make a rheologically balanced high fiber blend product in accordance with the present invention, the water absorption characteristics of the desired fiber ingredients must be determined.",
"The present invention is further directed to a method for determining the water absorption characteristics of the fiber ingredient and balancing those characteristics with another fiber ingredient having different water absorption characteristics.",
"In accordance with the present invention, a method based on the Farinograph® instrument is used to determine the water absorption characteristics of the desired fiber ingredient.",
"This method is described in Example 1 below.",
"EXAMPLE 1 [0050] To design a theologically balanced high fiber premix for breads and similar products, it is first necessary to measure the effects of the various fiber ingredients on dough rheology.",
"This is accomplished with the Farinograph® instrument.",
"By replacing 10% of the flour in a flour-water dough with the fiber ingredient and maintaining absorption at a constant level, it is possible to determine how much the rheology is affected by the various fibers relative to each other and relative to the Farinograph® curve of a reference flour ( FIG. 1 ).",
"Some fibers will yield doughs with higher peak Brabender Unit (BU) values ( FIG. 2 ) than the reference flour and will hence stiffen the dough.",
"Others yield lower peak BU values and hence plasticize the dough ( FIG. 3 ).",
"[0000] Farinograph® Instrument Method [0051] The absorption of the flour is determined using 480 g of dough.",
"The flour moisture is on an “as is”",
"basis.",
"The ingredients are dry blended for 1 minute with the water being added in its entirety within 30 seconds.",
"[0052] Farinograph® instrument conditions: [0053] 300 gram bowl [0054] Bowl temperature: 77° F. [0055] Water temperature: 70° F. [0056] Farinograph® instrument rpm: 63 rpm [0057] Once the absorption has been established, as shown in FIG. 1 , where the curve is balanced on the 500 BU line, 10% of the flour is replaced with the fiber ingredient of interest.",
"The amount of water is kept constant and the Farinograph(l instrument is run until a peak has been determined.",
"The absorption of the flour in these examples was 65%.",
"Baker's Percent Control: Artisan bread flour 100 Water (65% abs) 65 Samples: Artisan bread flour 90 Sample Fiber Ingredient 10 Water 65 [0058] The theological effect information gathered by this method, as shown in Table 1, enables the formulation of theologically balanced high fiber premixes in accordance with the present invention.",
"In general, high fiber blends and premixes made in accordance with the present invention will have peak resistance values of between about 100 BU greater than the control BU value and about 100 BU less than the control BU value.",
"Preferably, high fiber blends and premixes made in accordance with the present invention will have peak resistance values of between about 50 BU greater than the control BU value and about 50 BU less than the control BU value.",
"More preferably, high fiber blends and premixes made in accordance with the present invention will have peak resistance values of between about 25 BU greater than the control BU value and about 25 BU less than the control BU value.",
"TABLE 1 Farinograph ® Instrument Parameters for High Fiber Ingredients in Combination with Flour (10:90) Peak Width Peak Time Arrival Departure Stability MTI** Ingredient Peak BU (BU) (min) (min) (min) (Min) (BU) Arabinogalactan 1 230 50 70 53 94* 41 10 F97 Inulin 2 260 40 40.5 31.5 60 28.5 20 Inulin-Standard 3 270 50 38 29 45* 16 10 Polydextrose 4 270 50 40 30 54* 24 10 Sugar 5 330 60 8.5 3 30.5 27.5 20 Gum Arabic 6 430 60 26.5 22.5 37.5 15 20 Inulin-LCHT 7 450 100 16 11.5 27.5 16 30 Actistar ™ RT 8 500 120 8.5 1.5 20 18.5 40 Flour 9 (Control) 510 100 10.5 3 20 17 20 Cottonseed Fiber 10 550 100 8 1.5 24.5 23 20 Soy Fiber (SF) 11 590 110 8 1 22.5 21.5 20 Aleurone 12 630 100 5.5 2 12 10 40 Joshi (Corn Bran) 13 700 120 5.5 1.75 9.5 7.75 90 Oat fiber 14 740 160 7.5 2.25 20 17.75 60 Soy Cotyledon fiber 5 880 190 8 3 27 24 20 Psyllium 16 >1000 *Longer curves would be necessary to find the actual departure times.",
"**Farinograph ® Instrument Mixing Tolerance Index 1 Larex Inc., MN 2 Oliggo-Fiber ™ F97, Cargill, Inc., MN 3 Oliggo-Fiber ™ standard, Cargill, Inc., MN 4 Sta-Lit ® III 7, Tate and Lyle, IL 5 Granulated sugar, Cargill, Inc., MN 6 Nutraloid Arabic Spray Powder, TIC, MD 7 Oliggo-Fiber ™ LCHT, Cargill, Inc., MN 8 C*Actistar Actistar ™ RT (resistant starch), Cargill, Inc., MN 9 Cargill “Progressive Baker Artisan Bread Flour”, Cargill, Inc., MN 10 I7C, Just Fiber, NY 11 Soybean Hull Fiber, Fibred, MD 12 GrainWise ™ , Cargill, Inc., MN 13 MaizeWise ™ , Cargill, Inc., MN 14 Hesco, SD 15 Ingredient in development, Cargill, Inc., MN 16 Psyllium blond seed husk powder 40 mesh, BI Nutraceuticals, CA [0059] To effectively replace flour, however, it is also necessary to supplement the premix with an amount of vital wheat gluten equaling the amount of protein lost by replacing the flour with a fiber ingredient.",
"[0060] For example, if a flour contains 12% protein, for every 10% of the flour replaced by a fiber ingredient, 1.2% of flour protein has been removed from the system.",
"Since vital wheat gluten (VWG) is normally only about half as functional as the native gluten it replaces, it is added as a component of the premix at about double the level required to replace the removed flour protein to maintain constant functionality.",
"The amount of VWG added can vary significantly, however, depending on the functionality of the flour protein replaced and the vital wheat gluten itself.",
"The fiber ingredients (stiffening and plasticizing) are added to the premix formula at a level of 100% minus the gluten percentage in a ratio required to balance the total formula rheology.",
"[0061] To make a premix using the rheologically balanced high fiber blend, the final step is to identify the right blend of gluten, stiffening fiber and plasticizing fiber to yield a high fiber premix that does not significantly affect dough rheology when it replaces a portion of the flour in the formula.",
"The VWG percentage in the premix and the total level of fibers are determined as described above.",
"An approximate desired total dietary fiber (TDF) content of the finished bread is then chosen.",
"A practical TDF content is one between the low end of a desired fiber level range (e.g., 10% of the US FDA's Recommended Daily Allowance or Daily Reference Value, or RDA/DRV—a good source of fiber) and the high end of the range (e.g., 20% of the RDA/DRV—an excellent source of fiber), with the current RDA/DRV for fiber being 25 grams, in the finished product to assure replacement levels of both the gluten and the fiber blend are optimal.",
"When the RDA/DRV level is set, the corresponding flour replacement level is used to determine the ratio of the stiffening and plasticizing fibers in the premix.",
"This is determined experimentally using the Farinograph® instrument method so that the water requirement of the original flour is duplicated, as shown in FIG. 4 .",
"[0000] Aleurone-Inulin Premix [0062] In this example, the following high fiber blend in a premix form was determined to be suitable for use on a commercial scale.",
"Premix 1 Composition VWG 20% Aleurone 52% Inulin-Standard 28% [0063] The total dietary fiber content of this premix is about 42%.",
"To produce a. “good source of fiber”-containing bread, the manufacturer would replace 16% of the flour in the formula with this premix.",
"To produce an “excellent source of fiber”-containing bread, the manufacturer would replace 34% of the flour in the formula with this premix.",
"EXAMPLE 1A [0064] This example demonstrates the effects on rheology and quality of removing inulin or aleurone from the rheologically balanced high fiber blend described in Example 1.",
"These non-balanced premixes clearly demonstrate the effects of the single fiber ingredient on the rheological properties of the dough.",
"Premix 1 Composition with Inulin Removed: VWG 18% Aleurone 82% [0065] The total dietary fiber content of this premix is about 42%.",
"To produce a “good source of fiber”-containing bread, 18% of the flour in the formula was replaced with this premix.",
"The results are shown in FIG. 5 , which shows that the Farinograph® curve is significantly higher than the reference line at 500 BU.",
"Premix 1 Composition with Aleurone Removed: VWG 18% Inulin-Standard 82% [0066] The total dietary fiber content of this premix is about 59%.",
"To produce a “good source of fiber”-containing bread, 13% of the flour in the formula was replaced with this premix.",
"The results are shown in FIG. 6 , which shows that the Farinograph® curve is significantly lower than the reference line at 500 BU.",
"[0067] Breads were baked using the rheologically balanced high fiber premix of the present invention and were compared to the non-balanced fiber premixes using the bread formula in Table 2 and the following processing procedures.",
"TABLE 2 Formulas for High Fiber Breads Baker's Ingredient Percent Wheat flour, enriched 1 100-value in Table 3 Premix See Table 3 HFCS 2 10.0 Soybean oil 3 2.0 Panalite ® SV 4 0.5 Salt 5 2.0 Dough Conditioner 6 1.5 Compressed yeast 7 4.0 Water 60.0 Total 180.0 1 Cargill “Progressive Baker Artisan Bread Flour”, Cargill, Inc., MN 2 IsoClear ™, Cargill, Inc., MN 3 Cargill Soybean Salad Oil (soybean oil with citric acid as preservative), Cargill, Inc., MN 4 ADM Arkady Panalite ® 50 SVK emulsifier, ADM, IL 5 Evaporated food grade salt, United Salt Corp.",
", TX 6 S-500 conditioner, Puratos Corp.",
", NJ 7 Eagle, Lallemand, Inc., Montreal, Canada [0068] An approximately 1200 gram batch of dough was mixed in a Hobart mixer equipped with a McDuffey bowl for 1 minute on low speed and 8 minutes on medium speed.",
"480 grams of dough were scaled and placed in a Farinograph® instrument.",
"Brabender units of this dough were recorded.",
"The remainder of the dough was then allowed to rest for 10 minutes and four 160 gram pieces of dough were scaled.",
"The dough was then allowed another 10 minute rest before the dough was sheeted and rolled with a Moline Bread Molder (final gap setting=1.5, pressure board setting=6).",
"The dough was allowed to proof for 50 minutes and then baked 16 minutes at 400° F. Specific volume was determined by dividing the volume of the loaves by their weight after cooling for 1 hour.",
"The following results (shown in Table 3) were obtained: TABLE 3 Dough Rheology and Bake Data for Rheologically Balanced and Unbalanced Dough Systems Brabender High Fiber Bread Flour Units of Specific Volume Premix Composition Replacement Bread Dough (cc/g) of (see formulas above) Level (%) After Mixing Finished Bread Control (no premix) 0 510 6.4 aleurone, inulin, VWG 1 16 500 5.5 aleurone, inulin, VWG 34 520 4.6 aleurone, VWG 18 700 5.4 aleurone, VWG 34 >700 <3.0 inulin,VWG 13 380 5.1 inulin, VWG >13 could not n.a. process 1 Vital Wheat Gluten (made in Poland), Cargill, Inc., MN [0069] As can been seen from the data in Table 3, the rheologically balanced high fiber blend of the present invention resulted in a dough that had substantially the same rheology as a control dough and therefore did not require significant adjustments to the water content of the formula or to the processing parameters, and resulted in a baked product having a desirable specific volume even at the “excellent source of fiber”",
"level (34% flour replacement).",
"The individual fiber ingredients, used alone in the dough formulation, did not result in acceptable doughs.",
"Rheology of these doughs was affected dramatically with Brabender units of mixed doughs changing more than 100 than the control in all cases.",
"This led to severe processing issues in some cases and made processing of the dough into a finished product impossible in one case (i.e., the last data set in Table 3 for the composition containing only inulin and VWG at levels greater than 13% flour replacement).",
"EXAMPLE 2 Cottonseed Fiber-Inulin Premix Composition [0070] Using the methodology described above, another premix composition in accordance with the present invention was formulated as follows: Premix 2 Composition VWG 25% Cottonseed Fiber 47% Inulin-Standard 28% [0071] The total dietary fiber content of this premix is about 61%.",
"To produce a “good source of fiber”-containing bread, a manufacturer would replace 10% of the flour in the formula with this premix.",
"To produce an “excellent source of fiber”-containing bread, the manufacturer would replace 20% of the flour in the formula with this premix.",
"FIG. 7 shows the Farinograph® curve of a dough made with 10% of this premix and 90% flour at 65% absorption.",
"As can be seen in FIG. 7 , the dough made with this rheologically balanced premix has the desired Farinograph® curve at 500 BU.",
"Premix 2 Composition with Inulin Removed VWG 28% Cottonseed 72% [0072] The total dietary fiber of this premix is 61%.",
"To produce a “good source of fiber”-containing bread, the manufacturer would replace 9.2% of the flour in the formula with this premix.",
"To produce an “excellent source of fiber”-containing bread, the manufacturer would replace 18.4% of the flour in the formula with this premix.",
"FIG. 8 shows the Farinograph® curve of a dough made with 9.2% of this premix and 90.8% at 65% absorption.",
"As seen in FIG. 8 , the dough made with this non-balanced premix at a level needed to produce a “good source of fiber”-containing bread was not theologically acceptable.",
"[0073] The results for the premix composition with the cottonseed removed are shown in FIG. 6 described above.",
"[0074] Bread was prepared with these theologically balanced and non-balanced premixes using the general formula and procedures describes in Example 1A.",
"Dough rheology and bake data for these evaluations is summarized in Table 4.",
"TABLE 4 Dough Rheology and Bake Data for Rheologically Balanced and Unbalanced Dough Systems (Cottonseed, inulin, VWG) Brabender High Fiber Bread Flour Units of Specific Volume Premix Composition Replacement Bread Dough (cc/g) of Finished (see formulas above) Level (%) After Mixing Bread Control (no premix) 0 480 6.3 Cottonseed fiber, 10 480 5.8 inulin, VWG Cottonseed fiber, 20 450 6.0 inulin, VWG Cottonseed fiber, 9.2 560 6.2 VWG Cottonseed fiber, 18.4 650 5.3 VWG Inulin, VWG 13 380 5.1 Inulin, VWG >13 could not n.a. process [0075] As seen in Table 4, this rheologically balanced high fiber blend premix resulted in dough products that had nearly identical Farinograph® instrument data as the control product, and produced bread products with substantially similar specific volumes as that control product.",
"The non-balanced premixes resulted in dough products that would require a substantial amount of processing adjustment in order to be commercially feasible.",
"EXAMPLE 3 Polydextrose-Psyllium Premix Composition [0076] In this example, two fiber ingredients with radical effects on dough rheology were chosen to develop a theologically balanced high fiber premix.",
"Polydextrose has a very strong plasticizing effect, while psyllium husk powder has a very strong stiffening effect, as shown in FIGS. 9 and 10 described below.",
"In comparison, the Farinograph® curve of a control flour-water dough at 69% absorption would balance on the 500 BU line.",
"[0077] FIG. 9 shows a Farinograph(&",
"curve of a dough made with 10% polydextrose and 90% flour at 69% absorption.",
"As seen in this Figure, the use of polydextrose results in a Farinograph® curve that is substantially lower than the reference line at 500 BU.",
"This dough was soup-like in consistency.",
"[0078] FIG. 10 shows a Farinograph® curve of a dough made with 10% psyllium husk powder and 90% flour at 69% absorption.",
"As seen in this Figure, the use of psyllium husk powder results in a Farinograph(&",
"curve that is significantly greater than the reference line at 500 BU.",
"This dough was very hard and dry.",
"[0079] Consequently, using either of these fibers as the sole source of fiber in a high fiber bread formula would cause very significant rheology issues.",
"[0080] The following premix composed of psyllium, polydextrose and gluten was developed using the procedure described in Example 1.",
"Premix 3 Composition VWG 20% Psyllium Husk Powder 15% Polydextrose 65% [0081] The total dietary fiber of the premix is about 72%.",
"To produce a “good source of fiber”-containing bread, the manufacturer would replace 10% of the flour in the formula with this premix.",
"To produce an “excellent source of fiber”-containing bread, the manufacturer would replace 22% of the flour in the formula with this premix.",
"[0082] FIG. 11 shows a Farinograph® curve of a dough made with 10% of the VWG/Psyllium/Polydextrose premix and 90% flour at 69% absorption.",
"FIG. 12 shows a Farinograph® curve of a dough made with 22% of the VWG/Psyllium/Polydextrose premix and 78% flour at 69% absorption.",
"As seen in these figures, despite the drastic adverse effects on dough rheology of the individual fiber components, by using the rheologically balanced high fiber blend premix of the present invention, a processable dough rheology can be achieved, with a Farinograph® curve near the 500 BU reference line.",
"[0083] Bread was produced with this premix using the general formula and procedures described in Example 1A.",
"Dough rheology and bake data for these evaluations are contained in Table 5.",
"TABLE 5 Dough Rheology and Bake Data for Balanced Psyllium Husk Powder, Polydextrose, VWG Dough Systems High Fiber Bread Flour Brabender Units Specific Volume Premix Composition Replacement Of Bread Dough (cc/g) of Finished (see formula above) Level (%) After Mixing Bread Control (no premix) 0 460 6.45 Psyllium, 10 470 6.16 polydextrose, VWG Psyllium, 22 450 5.09 polydextrose, VWG [0084] In this example, due to the drastic effects on dough rheology caused by each of psyllium and polydextrose individually, a bread dough was not prepared using just one of these ingredients as the fiber source due to anticipated damage to the processing equipment and overall lack of processability.",
"[0085] As can be seen in Table 5, even though psyllium and polydextrose, as individual fiber ingredients, have significant adverse effects on the dough rheology, when they are combined to make a rheologically balanced high fiber blend premix of the present invention, they can be used to make a dough product having processing attributes that are substantially the same as a control product, and final product attributes that are quite suitable for conventional bakery products.",
"[0086] Although the foregoing specification and examples fully disclose and enable the present invention, they are not intended to limit the scope of the invention, which is defined by the claims appended hereto."
] |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-292298, filed Sep. 26, 2000, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an on-vehicle planar antenna device for receiving satellite broadcasting.
[0003] Conventionally, there has been no technique but decreasing an antenna element size when a planar antenna device is used for obtaining high electromagnetic field radiation characteristics within the range of a wide elevation angle.
[0004] [0004]FIG. 1 illustrates a structure of a general air patch antenna device. FIG. 1 shows a ground plane 11 , an antenna element 12 mounted on the ground plane 11 separated by a spacer 13 , and a feed point 14 to the antenna element 12 .
[0005] A microstrip antenna device stationed in the air (εr=1) has a high relative antenna device gain. On the other hand, however, the half-power angle generally becomes approximately 60° to 80° depending on antenna device shapes. Consequently, a gain remarkably decreases toward a low elevation angle.
[0006] To decrease the antenna element size for widening such a narrow elevation angle range, a dielectric must be used.
[0007] [0007]FIG. 2 illustrates an example structure of a dielectric patch antenna device using the dielectric. FIG. 2 shows a ground plane 21 , a dielectric plate 22 mounted on the ground plane 21 , an antenna element 23 provided on the dielectric plate 22 , and a feed point 24 to the antenna element 23 .
[0008] The size of the antenna element 23 is decreased by using the dielectric plate 22 . It becomes possible to obtain high electromagnetic field radiation characteristics within a wide elevation angle range.
[0009] However, the antenna element size is decreased for the dielectric patch antenna device in FIG. 2. Compared to the air patch antenna device in FIG. 1, the antenna device gain greatly decreases. In addition, a loss due to the dielectric plate 22 further decreases the antenna device gain. As a result, the dielectric patch antenna device in FIG. 2 does not provide so high a radiation level toward a low elevation angle.
BRIEF SUMMARY OF THE INVENTION
[0010] An object of the present invention is to provide a planar antenna device which satisfies both of electromagnetic field radiation characteristics over a wide elevation angle range including a low elevation angle direction and a high antenna device gain.
[0011] A planar antenna device according to the present invention comprises: a ground plane; a planar antenna element having a principal plane mounted above the ground plane; and a cavity, having an opening partially exposing the antenna element, placed on the ground plane in order to cover the entire antenna element contactlessly.
[0012] Preferred manners for the above-mentioned planar antenna device are as follows.
[0013] (1) A feed point for supplying power supply to the antenna element is further provided.
[0014] (2) An area of the opening is smaller than a size of the antenna element.
[0015] (3) The opening is placed substantially parallel to a principal plane of the antenna element.
[0016] (4) The antenna element is an air patch antenna element mounted above the ground plane separated by a spacer.
[0017] Another planar antenna device according to the present invention comprises a ground plane; a planar antenna element having a principal plane mounted above the ground plane; and a planar conductor placed substantially parallel to a principal plane of the antenna element and having an opening at substantially a center thereof.
[0018] According to the present invention, it is possible to provide excellent electromagnetic field radiation characteristics over a wide elevation angle range including a low elevation angle direction and a high antenna device gain only by adding a cavity to a conventional air patch antenna device without decreasing the antenna element size, thereby maintaining sufficiently high antenna device gain.
[0019] Further, the present invention eliminates the need to use a dielectric for obtaining a gain toward a low elevation angle. It is possible to maintain a high antenna device gain without decreasing an antenna device gain due to a dielectric loss.
[0020] Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0021] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention.
[0022] [0022]FIG. 1 is a perspective view exemplifying a structure of a conventional air patch antenna device;
[0023] [0023]FIG. 2 is a perspective view exemplifying a structure of a conventional dielectric patch antenna device;
[0024] [0024]FIG. 3 is a perspective view illustrating a structure of an antenna device according to an embodiment of the present invention for receiving BS digital broadcasting;
[0025] [0025]FIG. 4 is a sectional view of an antenna device structure taken along the line 4 - 4 of FIG. 3;
[0026] [0026]FIG. 5 shows VSWR characteristics of an antenna device according to an embodiment of the present invention;
[0027] [0027]FIG. 6 shows return loss characteristics of an antenna device according to an embodiment of the present invention;
[0028] [0028]FIG. 7 is a Smith chart for an antenna device according to an embodiment of the present invention;
[0029] [0029]FIG. 8 shows gain characteristics of an antenna device according to an embodiment of the present invention in comparison with conventional antenna devices corresponding to azimuth angles at a horizontal plane;
[0030] [0030]FIGS. 9A through 9C show directivities of an antenna device according to an embodiment of the present invention and conventional antenna devices; and
[0031] [0031]FIG. 10 is a modification of an antenna device according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] An embodiment of the planar antenna device according to the present invention will be described in further detail with reference to the accompanying drawings.
[0033] [0033]FIG. 3 is a perspective view illustrating a structure of a planar antenna device according to the present invention. FIG. 4 is a sectional view taken along the line 4 - 4 of FIG. 3.
[0034] In FIG. 3, an antenna element 33 is mounted above a ground plane 31 via a spacer 32 so that the antenna element 33 is separated from the ground plane 31 . This antenna element 33 is excited by power from the feed point 34 . The ground plane 31 is made of a metal plate such as brass, aluminum, stainless steel, and the like. The spacer 32 is made of synthetic resin such as polyacetal, polycarbonate, ABS, and the like. The antenna element 33 is made of a metal plate such as brass, aluminum, and the like.
[0035] A box-like cavity 35 is placed on the ground plane 31 so as to cover the entire antenna element 33 . The cavity 35 is made of a metal plate such as brass, aluminum, and the like.
[0036] The cavity 35 is provided so that it does not touch the antenna element 33 with a predetermined distance. A square opening 35 a , which is smaller than a size of the antenna element 33 , is formed at a surface a cavity 35 which is opposite to the antenna element 33 .
[0037] The opening 35 a of this cavity 35 is formed in order to provide high electromagnetic field radiation characteristics in a wide range of elevation angles, especially toward a low elevation angle without reducing the size of the antenna element 33 . It is possible to change electromagnetic field radiation characteristics especially toward a low elevation angle by adjusting the size of the opening 35 a with reference to the antenna element 33 and a distance between the opening 35 a and the antenna element 33 .
[0038] In the above-mentioned antenna device structure, various characteristics observed from experiments will be described as follows.
[0039] First, characteristics of the antenna device itself will be described with reference to FIGS. 6 through 7.
[0040] [0040]FIGS. 5 through 7 show an experimental voltage standing-wave ratio (VSWR), a return loss corresponding to the VSWR, and a Smith chart, respectively. Any of the characteristics FIGS. 5 through 7 indicates that an excellent performance is available at approximately 2.34 GHz with an input impedance of 50 Ω.
[0041] [0041]FIGS. 8 through 9C exemplify characteristics of the antenna device according to the embodiment of the present invention in comparison with the air patch antenna device in FIG. 1 and the dielectric patch antenna device in FIG. 2.
[0042] [0042]FIG. 8 shows gain characteristics corresponding to azimuth angles at a horizontal plane. A characteristic a indicated by a thin line corresponds to the air patch antenna device in FIG. 1. A characteristic β indicated by a broken line corresponds to the dielectric patch antenna device in FIG. 2. A characteristic γ indicated by thick lines corresponds to the antenna device with the cavity 35 in FIGS. 3 and 4 according to this embodiment.
[0043] As shown in FIG. 8, the air patch antenna device showing the characteristic α provides a high gain at around azimuth angle 0° , but causes large gain changes corresponding to azimuth angles. The air patch antenna device in FIG. 8 is found to be inappropriate for, especially, an on-vehicle antenna device which always changes antenna device angles according to directions of radio waves received.
[0044] The dielectric patch antenna device showing the characteristic β decreases the antenna element size and causes a dielectric loss, decreasing the total gain for the entire antenna device.
[0045] By contrast, the antenna device according to this embodiment showing the characteristic γ causes a little change in gains according to azimuth angles and is found to be suited for an antenna device which always changes antenna device angles in accordance with directions of radio waves received.
[0046] [0046]FIGS. 9A through 9C show directivities of the antenna devices explained in FIG. 8.
[0047] [0047]FIG. 9A exemplifies a directivity of the air patch antenna device. The directivity is valid only in a front direction and within a high elevation angle range. It is understood that the directive range is very narrow.
[0048] [0048]FIG. 9B exemplifies a directivity of the dielectric patch antenna device. Compared to the air patch antenna device in FIG. 9A, the dielectric patch antenna device in FIG. 9B increases a characteristic at the azimuth angle and toward a low elevation angle. However, it is understood that the directivity is unsatisfactory.
[0049] [0049]FIG. 9C exemplifies a directivity of the antenna device with the cavity 35 according to this embodiment. The antenna device in FIG. 9C provides the directivity in a very wide range not only at the azimuth angle on the horizontal plane, but also at elevation angles especially ranging from low to high elevation-angle directions.
[0050] As mentioned above, the antenna device structure with the cavity 35 according to this embodiment of the present invention can maintain high electromagnetic field radiation characteristics over a wide elevation angle range from a low elevation-angle direction. It is also possible to provide a sufficiently high total gain for the entire antenna device.
[0051] Compared to a quadrifilar helical antenna device, a cross di-pole antenna device, and the like having high efficiency and low elevation-angle radiation characteristics, the antenna device according to this embodiment of the present invention provides the following advantages.
[0052] (1) Simplifying a structure of the entire antenna device including a feed structure.
[0053] (2) Providing a mechanically solid structure having the rigid cavity for guarding the antenna element with no sharp projections.
[0054] (3) Easily manufacturing the antenna device.
[0055] (4) Easily thinning the entire antenna device structure.
[0056] The antenna device according to the present invention can be easily mass-produced and be suitably mounted on vehicles such as cars.
[0057] The above-mentioned embodiment provides an air patch antenna device with the cavity 35 . The present invention is not limited thereto.
[0058] For example, in the embodiment, an elevation radiation characteristic is improved by providing the cavity, but a rectangular conductor 36 having an opening (or may be a circular conductor, or a linear conductor like a wire etc.) as shown in FIG. 10 may be provided like the cavity 35 . That is, any conductor may be used to define an aperture of the antenna. With this configuration, the same advantage can be obtained as the above-mentioned embodiment.
[0059] The present invention is not limited to above-mentioned embodiment, and can be achieved in a scope of the invention.
[0060] Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. | A planar antenna device comprises a ground plane, a planar antenna element having a principal plane mounted above the ground plane, and a cavity, having an opening partially exposing the antenna element, placed on the ground plane in order to cover the entire antenna element contactlessly. | Concisely explain the essential features and purpose of the invention. | [
"CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-292298, filed Sep. 26, 2000, the entire contents of which are incorporated herein by reference.",
"BACKGROUND OF THE INVENTION [0002] The present invention relates to an on-vehicle planar antenna device for receiving satellite broadcasting.",
"[0003] Conventionally, there has been no technique but decreasing an antenna element size when a planar antenna device is used for obtaining high electromagnetic field radiation characteristics within the range of a wide elevation angle.",
"[0004] [0004 ]FIG. 1 illustrates a structure of a general air patch antenna device.",
"FIG. 1 shows a ground plane 11 , an antenna element 12 mounted on the ground plane 11 separated by a spacer 13 , and a feed point 14 to the antenna element 12 .",
"[0005] A microstrip antenna device stationed in the air (εr=1) has a high relative antenna device gain.",
"On the other hand, however, the half-power angle generally becomes approximately 60° to 80° depending on antenna device shapes.",
"Consequently, a gain remarkably decreases toward a low elevation angle.",
"[0006] To decrease the antenna element size for widening such a narrow elevation angle range, a dielectric must be used.",
"[0007] [0007 ]FIG. 2 illustrates an example structure of a dielectric patch antenna device using the dielectric.",
"FIG. 2 shows a ground plane 21 , a dielectric plate 22 mounted on the ground plane 21 , an antenna element 23 provided on the dielectric plate 22 , and a feed point 24 to the antenna element 23 .",
"[0008] The size of the antenna element 23 is decreased by using the dielectric plate 22 .",
"It becomes possible to obtain high electromagnetic field radiation characteristics within a wide elevation angle range.",
"[0009] However, the antenna element size is decreased for the dielectric patch antenna device in FIG. 2. Compared to the air patch antenna device in FIG. 1, the antenna device gain greatly decreases.",
"In addition, a loss due to the dielectric plate 22 further decreases the antenna device gain.",
"As a result, the dielectric patch antenna device in FIG. 2 does not provide so high a radiation level toward a low elevation angle.",
"BRIEF SUMMARY OF THE INVENTION [0010] An object of the present invention is to provide a planar antenna device which satisfies both of electromagnetic field radiation characteristics over a wide elevation angle range including a low elevation angle direction and a high antenna device gain.",
"[0011] A planar antenna device according to the present invention comprises: a ground plane;",
"a planar antenna element having a principal plane mounted above the ground plane;",
"and a cavity, having an opening partially exposing the antenna element, placed on the ground plane in order to cover the entire antenna element contactlessly.",
"[0012] Preferred manners for the above-mentioned planar antenna device are as follows.",
"[0013] (1) A feed point for supplying power supply to the antenna element is further provided.",
"[0014] (2) An area of the opening is smaller than a size of the antenna element.",
"[0015] (3) The opening is placed substantially parallel to a principal plane of the antenna element.",
"[0016] (4) The antenna element is an air patch antenna element mounted above the ground plane separated by a spacer.",
"[0017] Another planar antenna device according to the present invention comprises a ground plane;",
"a planar antenna element having a principal plane mounted above the ground plane;",
"and a planar conductor placed substantially parallel to a principal plane of the antenna element and having an opening at substantially a center thereof.",
"[0018] According to the present invention, it is possible to provide excellent electromagnetic field radiation characteristics over a wide elevation angle range including a low elevation angle direction and a high antenna device gain only by adding a cavity to a conventional air patch antenna device without decreasing the antenna element size, thereby maintaining sufficiently high antenna device gain.",
"[0019] Further, the present invention eliminates the need to use a dielectric for obtaining a gain toward a low elevation angle.",
"It is possible to maintain a high antenna device gain without decreasing an antenna device gain due to a dielectric loss.",
"[0020] Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.",
"The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.",
"BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING [0021] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention.",
"[0022] [0022 ]FIG. 1 is a perspective view exemplifying a structure of a conventional air patch antenna device;",
"[0023] [0023 ]FIG. 2 is a perspective view exemplifying a structure of a conventional dielectric patch antenna device;",
"[0024] [0024 ]FIG. 3 is a perspective view illustrating a structure of an antenna device according to an embodiment of the present invention for receiving BS digital broadcasting;",
"[0025] [0025 ]FIG. 4 is a sectional view of an antenna device structure taken along the line 4 - 4 of FIG. 3;",
"[0026] [0026 ]FIG. 5 shows VSWR characteristics of an antenna device according to an embodiment of the present invention;",
"[0027] [0027 ]FIG. 6 shows return loss characteristics of an antenna device according to an embodiment of the present invention;",
"[0028] [0028 ]FIG. 7 is a Smith chart for an antenna device according to an embodiment of the present invention;",
"[0029] [0029 ]FIG. 8 shows gain characteristics of an antenna device according to an embodiment of the present invention in comparison with conventional antenna devices corresponding to azimuth angles at a horizontal plane;",
"[0030] [0030 ]FIGS. 9A through 9C show directivities of an antenna device according to an embodiment of the present invention and conventional antenna devices;",
"and [0031] [0031 ]FIG. 10 is a modification of an antenna device according to the present invention.",
"DETAILED DESCRIPTION OF THE INVENTION [0032] An embodiment of the planar antenna device according to the present invention will be described in further detail with reference to the accompanying drawings.",
"[0033] [0033 ]FIG. 3 is a perspective view illustrating a structure of a planar antenna device according to the present invention.",
"FIG. 4 is a sectional view taken along the line 4 - 4 of FIG. 3. [0034] In FIG. 3, an antenna element 33 is mounted above a ground plane 31 via a spacer 32 so that the antenna element 33 is separated from the ground plane 31 .",
"This antenna element 33 is excited by power from the feed point 34 .",
"The ground plane 31 is made of a metal plate such as brass, aluminum, stainless steel, and the like.",
"The spacer 32 is made of synthetic resin such as polyacetal, polycarbonate, ABS, and the like.",
"The antenna element 33 is made of a metal plate such as brass, aluminum, and the like.",
"[0035] A box-like cavity 35 is placed on the ground plane 31 so as to cover the entire antenna element 33 .",
"The cavity 35 is made of a metal plate such as brass, aluminum, and the like.",
"[0036] The cavity 35 is provided so that it does not touch the antenna element 33 with a predetermined distance.",
"A square opening 35 a , which is smaller than a size of the antenna element 33 , is formed at a surface a cavity 35 which is opposite to the antenna element 33 .",
"[0037] The opening 35 a of this cavity 35 is formed in order to provide high electromagnetic field radiation characteristics in a wide range of elevation angles, especially toward a low elevation angle without reducing the size of the antenna element 33 .",
"It is possible to change electromagnetic field radiation characteristics especially toward a low elevation angle by adjusting the size of the opening 35 a with reference to the antenna element 33 and a distance between the opening 35 a and the antenna element 33 .",
"[0038] In the above-mentioned antenna device structure, various characteristics observed from experiments will be described as follows.",
"[0039] First, characteristics of the antenna device itself will be described with reference to FIGS. 6 through 7.",
"[0040] [0040 ]FIGS. 5 through 7 show an experimental voltage standing-wave ratio (VSWR), a return loss corresponding to the VSWR, and a Smith chart, respectively.",
"Any of the characteristics FIGS. 5 through 7 indicates that an excellent performance is available at approximately 2.34 GHz with an input impedance of 50 Ω.",
"[0041] [0041 ]FIGS. 8 through 9C exemplify characteristics of the antenna device according to the embodiment of the present invention in comparison with the air patch antenna device in FIG. 1 and the dielectric patch antenna device in FIG. 2. [0042] [0042 ]FIG. 8 shows gain characteristics corresponding to azimuth angles at a horizontal plane.",
"A characteristic a indicated by a thin line corresponds to the air patch antenna device in FIG. 1. A characteristic β indicated by a broken line corresponds to the dielectric patch antenna device in FIG. 2. A characteristic γ indicated by thick lines corresponds to the antenna device with the cavity 35 in FIGS. 3 and 4 according to this embodiment.",
"[0043] As shown in FIG. 8, the air patch antenna device showing the characteristic α provides a high gain at around azimuth angle 0° , but causes large gain changes corresponding to azimuth angles.",
"The air patch antenna device in FIG. 8 is found to be inappropriate for, especially, an on-vehicle antenna device which always changes antenna device angles according to directions of radio waves received.",
"[0044] The dielectric patch antenna device showing the characteristic β decreases the antenna element size and causes a dielectric loss, decreasing the total gain for the entire antenna device.",
"[0045] By contrast, the antenna device according to this embodiment showing the characteristic γ causes a little change in gains according to azimuth angles and is found to be suited for an antenna device which always changes antenna device angles in accordance with directions of radio waves received.",
"[0046] [0046 ]FIGS. 9A through 9C show directivities of the antenna devices explained in FIG. 8. [0047] [0047 ]FIG. 9A exemplifies a directivity of the air patch antenna device.",
"The directivity is valid only in a front direction and within a high elevation angle range.",
"It is understood that the directive range is very narrow.",
"[0048] [0048 ]FIG. 9B exemplifies a directivity of the dielectric patch antenna device.",
"Compared to the air patch antenna device in FIG. 9A, the dielectric patch antenna device in FIG. 9B increases a characteristic at the azimuth angle and toward a low elevation angle.",
"However, it is understood that the directivity is unsatisfactory.",
"[0049] [0049 ]FIG. 9C exemplifies a directivity of the antenna device with the cavity 35 according to this embodiment.",
"The antenna device in FIG. 9C provides the directivity in a very wide range not only at the azimuth angle on the horizontal plane, but also at elevation angles especially ranging from low to high elevation-angle directions.",
"[0050] As mentioned above, the antenna device structure with the cavity 35 according to this embodiment of the present invention can maintain high electromagnetic field radiation characteristics over a wide elevation angle range from a low elevation-angle direction.",
"It is also possible to provide a sufficiently high total gain for the entire antenna device.",
"[0051] Compared to a quadrifilar helical antenna device, a cross di-pole antenna device, and the like having high efficiency and low elevation-angle radiation characteristics, the antenna device according to this embodiment of the present invention provides the following advantages.",
"[0052] (1) Simplifying a structure of the entire antenna device including a feed structure.",
"[0053] (2) Providing a mechanically solid structure having the rigid cavity for guarding the antenna element with no sharp projections.",
"[0054] (3) Easily manufacturing the antenna device.",
"[0055] (4) Easily thinning the entire antenna device structure.",
"[0056] The antenna device according to the present invention can be easily mass-produced and be suitably mounted on vehicles such as cars.",
"[0057] The above-mentioned embodiment provides an air patch antenna device with the cavity 35 .",
"The present invention is not limited thereto.",
"[0058] For example, in the embodiment, an elevation radiation characteristic is improved by providing the cavity, but a rectangular conductor 36 having an opening (or may be a circular conductor, or a linear conductor like a wire etc.) as shown in FIG. 10 may be provided like the cavity 35 .",
"That is, any conductor may be used to define an aperture of the antenna.",
"With this configuration, the same advantage can be obtained as the above-mentioned embodiment.",
"[0059] The present invention is not limited to above-mentioned embodiment, and can be achieved in a scope of the invention.",
"[0060] Additional advantages and modifications will readily occur to those skilled in the art.",
"Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein.",
"Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents."
] |
This is a division, of application Ser. No. 692,339, filed June 3, 1976 now U.S. Pat. No. 4,135,870.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to an improvement in the art of forming foamed and unfoamed molded plastic articles.
2. Description of the Prior Art
"Additives" throughout this Specification and Claims are defined to mean substances or materials added to thermoplastic resins. Examples of such additives are flame retardants, U.V. stabilizers, blowing agents, colorants, etc. Examples of thermoplastic resins useful in this invention are polyethylene, polypropylene, polystyrene, polyvinyl chloride, copolymers thereof and the like. In general, any injection moldable thermoplastic resin can be used. The following, for purposes of discussion, considers prior art relating to blowing agent additives.
Prior methods and apparatus for adding blowing agents to a plastic resin to form solid skin and foamed core (SSFC) articles are exemplified in the patents to De Vita, U.S. Pat. No. 3,746,492 (1973), D. F. Oxley, U.S. Pat. No. 3,751,534 (1973), P. J. Garner and D. F. Oxley, U.K. Pat. No. 1,156,217 (1969), and R. G. Angell, Jr. U.S. Pat. No. 3,436,446 (1969). In each of the above cited art, a blowing agent is introduced into a thermoplastic material to form a foamable plastic mixture. This mixture is then accumulated under pressure in an accumulator or an injector. An injector is used throughout this Specification and Claims to mean a device capable of both accumulating and injecting under pressure molten plastic into a mold. Some examples of injectors are the accumulators disclosed in the above cited art and reciprocating screw or plunger injection molding machines such as sold by Cincinnati Milacron.
One known method for injecting foamable and unfoamable plastic material alternately into a mold involves the use of two coupled injection systems, one for foamable and the other for unfoamable plastic materials. These systems are arranged to inject alternately through a single nozzle. Another known method uses a single injection system containing discrete layers of foamable and unfoamable plastic material. Upon injection, each discrete layer enters the mold separately, thereby injecting alternately in a single injection stroke foamable and unfoamable plastic into a mold.
There are several disadvantages inherent to these known methods. In the case where two injection systems are required, there are the substantial equipment costs and the need during filling for back-pressures in one of the injector systems to prevent premature foaming. Similarly, in the case where a single injection system employs discrete layers of foamable and unfoamable plastic, back-pressures on the foamable plastic material is required prior to injection in order to prevent premature foaming. In general, process control is more difficult where back-pressures are necessary. Further where an additive other than a blowing agent is added to a molten plastic before the molten plastic material is accumulated in an accumulator, degradation of said material often occurs to such a degree as to preclude the use of many otherwise useful additives.
H. L. Maiocco, U.S. Pat. No. 3,817,675 (1974) discloses an apparatus for introducing a measured quantity of colorants into a plasticized plastic stream just downstream of an extruder and just upstream of a mixer. This apparatus is similar to De Vita ('492) in that in De Vita a blowing agent instead of a colorant is introduced just downstream of an extruder and just upstream of a mixer.
Maiocco ('675) as disclosed has several limitations. There is no provision for selectively adding colorants to a plasticized plastic. There is no discussion concerning the addition of blowing agents, U.V. stabilizers or flame retardants. There is not disclosed the substitution of an injector for an extruder. That there is no means disclosed for selectively adding colorants makes a process of selectively introducing additives either into the skin or core of a molded plastic article very difficult to achieve. Since the substitution of an injector with its accumulation zone for an extruder is not disclosed, there is not taught a practical means for injecting in a periodic flow the quantities of a plasticized plastic often required during an injection molding cycle.
BRIEF DESCRIPTION OF THE INVENTION
In one embodiment, the invention comprises the utilization of a machine for producing foamed core and foamed or unfoamed solid skin molded plastic articles. A unique feature of this machine over that disclosed in the above cited prior art resides in the time and location of introducing an additive into a molten plastic. The time for the introduction of the additive in this invention is during the injection of molten plastic, and the location is downstream of an injector. The steps for introducing molten plastic material into a mold is as follows: (1) ejecting a molten plastic from an injector to form a stream, (2) introducing selectively an additive into said stream, (3) mixing the product of step (2), and (4) flushing out any additive-containing plastic between the point of introducing said additive and the mold entrance. The details of the step of flushing will be discussed later. This sequence of events is determined by a series of switches activated as a piston of an accumulator or an injector moves through "activation points" or "activation positions" during the emptying of said accumulator or injector. The timing and duration of each of the above events is determined by the rate of motion of said piston and distance between these activation points. The total time for steps (1) to (4) requires a maximum of approximately 30 seconds. The total cycle time depends upon several factors known to a man of skill in the art.
In another embodiment, the sequence of steps for introducing a material into a molded plastic article is (1) melting a thermoplastic resin, (2) transferring said thermoplastic resin to any accumulation zone where it is maintained in a molten state, (3) ejecting said resin from said accumulation zone to form a molten plastic stream, (4) introducing into said stream an additive, (5) mixing said additive and said stream to form a mixture thereof, and (6) channelling said mixture into a mold.
One or more mixers downstream from the accumulation zone of an injector insure uniform dispersion of the additive throughout the molten plastic. A measure of the efficiency of a mixer can be determined based upon the cell structure of the foamed plastic. Further, since the rate at which a molten plastic will fill a mold is dependent in part upon the pressure imposed upon said plastic, and since a pressure drop necessarily will result from the plastic flowing through one or more mixers prior to entering the mold, care must be exercised so that the pressure on the plastic at the point of injection into the mold is sufficient to insure rapid transfer of the plastic from the accumulator or injector into the mold.
In the above discussion, additive was used generically, but for purposes of clarity an example dealing with a blowing agent as an additive will be considered. One of the machines in this case can produce SSFC articles. To understand the operation of this machine, a discussion of four switches contained therein is necessary. A first switch signals that the injector is full and ready to begin filling the mold with plastic and a last switch closes a nozzle or gate to a mold. A second switch opens and a third closes a valve in a means for introducing a blowing agent into the ejected molten plastic. The distance between activation points for the first and second switches influences the amount by weight of unfoamable plastic which is injected into the mold before a blowing agent is introduced into the molten plastic. This initial shot of unfoamable plastic will influence the amount by weight of unfoamed skin on a finished part. The distance between the activation points for the second and third switches determines the amount by weight of foamed core formed in a resulting plastic part. The distance between the activation points for the third and fourth switches controls the process of flushing. The distance between the activation points of the third and fourth switches is adjusted to insure that sufficient unfoamable plastic is injected through the mixer and nozzle manifold so that all feed channels between the point of blowing agent introduction and the mold entrances are filled with unfoamable plastic and optionally, so that a final portion of plastic introduced into the mold is unfoamable. If flushing is complete, then the initial injection into the mold for the next part will be only unfoamable plastic. It is to be noted that pairwise the first and second, and the third and fourth switches can be combined. The result of combining switches is to provide a machine capable of uniformly distributing an additive throughout both the core and skin of a molded plastic article.
The blowing agent introduced into the molten plastic material may be either chemical or physical. Examples of physical blowing agents are compounds which are or become gaseous due to a change in physical state. Examples of such compounds are compressed air, nitrogen, pentane, hexane, etc. Examples of chemical blowing agents are substances which decompose giving rise to gases. Examples of such substances are azo compounds, semicarbazides, azides, diazoamino compounds, etc. In the case of a chemical blowing agent dispersion, the most efficient mixing occurs when the viscosity of the chemical blowing agent dispersion is comparable to that of the molten plastic material.
The quantity of chemical blowing agent dispersion introduced for a given period of time is determined by the pressure imposed upon and the resistance to flow of the chemical blowing agent dispersion. The flow rate of chemical blowing agent from a reservoir through a tube into a molten plastic material is controlled by two valves one a precision needle valve or other flow controlling means and the other an on-off valve such as an electrically controlled solenoid.
In a more generalized form, the invention comprises a method for introducing an additive into a molten plastic. Previously, the introducing of a blowing agent into a portion of injected molten plastic was considered. In a similar manner, additives such as U.V. stabilizers, flame retardants, and colorants can be introduced selectively so that they become part of either the skin and/or the core of a finished molded article. There are several reasons for introducing additives downstream of the injector in the manner disclosed; for example, the location of the additive in the core and/or in the skin of the finished molded article can be readily controlled; the length of time said additive is subjected to high temperatures and pressures is considerably reduced over cited art methods; and back-pressures such as discussed in the patent to De Vita ('492) during the filling of an accumulator or injector can be avoided. In general, colorants', flame retardants', and U.V. stabilizers' effectiveness is directly proportional to their concentration at or near the surface. Therefore, greater effectiveness for a given weight of such additives will occur if it is concentrated at or close to the surface rather than uniformly distributed throughout the molded plastic article. Further, as an additional advantage, the use of pigments selectively at the surface of a thick structural foam article permits the use of less pigment with a resulting savings in pigment costs.
It is an object of this invention to provide the utilization of a machine for introducing additives downstream of an injector.
It is an object of this invention to provide the utilization of a machine capable with minor adjustments of producing either swirl or swirl-free foamed core molded plastic articles.
It is an object of this invention to provide a method for using many additives which cannot otherwise be used in producing injection molded plastic articles.
It is an object of this invention to provide a method for selectively introducing additives either into the skin or core of a molded plastic article.
Other objects of this invention will be clear to a man of average skill in the art once the teachings of this Application are disclosed.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic diagram of an apparatus to add an additive such as a blowing agent to a molded plastic article.
FIG. 2 is the apparatus used to introduce a chemical blowing agent in the form of a dispersion into the molten plastic stream downstream of an injector and upstream of a mixer as viewed along line 2--2 of FIGS. 1 and 8.
FIG. 3 is the apparatus used to introduce a chemical or gaseous blowing agent at a wall downstream of an injector and upstream of a mixer.
FIG. 4 is a view along section line 4--4 of FIGS. 1 and 8.
FIG. 5 is a cross-section of a swirl-free SSFC thermoplastic article.
FIGS. 6 and 7 are cross-sectional views of molded plastic articles wherein an additive has been selectively added to the skin and core of each, respectively.
FIG. 8 is a schematic view of a portion of the machine of FIG. 1 wherein the extruder and accumulator have been replaced by a reciprocating screw injection molding machine.
The elements comprising the apparatus disclosed in FIG. 1 are an extruder 1, a passageway 24 between extruder 1 and an accumulator 12, a dump valve 2, a piston-activating means comprising a cylinder 5 having inlets and outlets 4 and 6, a conduit 13 for introducing an additive, a mixer 14, an injection nozzle manifold 15 and a series of microswitches 7, 8, 9, and 10.
Thermoplastic material (not shown) at the upstream end is fed into hopper 3 at a rate dependent upon cycle time. This material is melted and leaves the extruder at a temperature of about 325°-800° F. The amount of pressure by which the pressure on the plastic at the extruder head exceeds the back-pressure of the accumulator 12 can vary depending upon the plastic being processed. For example, if high shear is required either for mechanical heating or mixing then the amount of the excess pressure is above 500 psi. If on the other hand low shear is required to prevent undesirable mechanical heating then the amount of the excess pressure is below 500 psi. The extruded thermoplastic material moves through passageway 24 to an accumulator 12.
The accumulator 12 of FIG. 1 is in its emptied configuration so that as thermoplastic material moves from the extruder 1 to the accumulator 12 piston arm 25 moves to the left and accumulator 12 becomes filled with molten thermoplastic material. During filling of the accumulator 12, a back-pressure is maintained on the piston.
The injection cycle beginning with the emptying of accumulator 12 involves the following sequence: (1) just as accumulator 12 is completely filled, cam 11 activates a first microswitch 7 which signals that the accumulator is full and ready to begin filling the mold with plastic. In the event that a longer time than usual is required to ready the mold for the next injection of plastic, then either excess plastic from extruder 1 exits out through dump valve 2 or in the absence of dump valve 2, the screw of extruder 1 is stopped. When the mold is ready a valve (not shown) in the manifold 15 opens and molten plastic is injected from accumulator 12 past a point for introducing an additive, through mixer 14 containing mixer elements 52, into manifold 15 and then into a mold means 17-23; (2) cam 11 activates a second microswitch 8 which opens valve 45, thereby introducing into said injected molten plastic an additive prior to mixer 14 and downstream of accumulator 12; (3) cam 11 activates a third micro switch 9 which closes valve 45 thereby stopping the introduction of any more additive; and (4) cam 11 activates a fourth microswitch 10 which closes manifold 15 and the accumulator 12 begins to fill for the next cycle. It is to be noted that the on-off periods for the valve in the means for introducing an additive can be changed as in EXAMPLES 4 and 5 so that the additive is introduced into an exterior portion of the stream of molten plastic ejected from an injector, i.e., selectively introduced into the skin of a finished molded article. It is further to be noted that pairwise the first and second, and the third and fourth microswitches can be combined into two switches when it is desired to have the additive introduced both into the skin and core of the finished molded article.
The portion of the injection process which will hereinafter be referred to as the step of flushing is determined by the distance between microswitches 9 and 10. The step of flushing insures that all thermoplastic material containing any additive between the point of injection for such additives and the mold entrance points 31 and 32 is replaced by additive-free thermoplastic material. Optionally, additive-free molten plastic can be introduced as the last portion of plastic to enter the mold at the end of the injection cycle to "seal" the gate area. If the flushing is not complete, then during the next injection cycle there will be some additive in the thermoplastic material in a portion of the skin of the molded plastic article formed. If the additive being considered is a blowing agent, then a swirly surface will result.
Where there is a division point 30 which has several paths therefrom to a mold, care must be exercised as to the step of flushing because generally a different rate of flow of the thermoplastic material will occur within the different paths available. The difference in flow rate along these various paths to the mold cavity is a function of (1) the differences in resistance to flow caused by variations in diameter, and/or length of each path to the mold and (2) the differences in resistance to flow from each path through a particular mold gate as a result of the geometry of the mold. As a general rule of thumb, to insure roughly equivalent flow rates through the various paths, the pressure drop between the division point 30 to each of the injection points 31 and 32 should be substantially the same. Another way to insure complete removal of additive containing plastic material is to have a separate injector for each injection point.
Mixer 14 having a plurality of variously oriented mixer blades 52 provides very efficient mixing of injected thermoplastic material and an added blowing agent or other additive and does not decrease the pressure at the injection points 31 and 32 below about 200 psi. We have found that a static mixer by Kenics Corporation of Danvers, Massachusetts affords sufficient mixing and a pressure drop between the accumulator head and distribution point 30 of approximately 3-5 times that pressure drop caused by a tube of the same length and diameter as that enclosing the mixer but without any mixer elements or blades 52.
Several modifications to FIGS. 1 and 8 in keeping with this invention are: that dump valve 2 may be eliminated if microswitch 7 when activated will stop either the screw of extruder 1 or the reciprocating screw of the injection molding machine 1', that additional microswitches can be added, and that one or more additional means for introducing an additive can be attached to a passageway connecting accumulator 12 or reciprocating screw injector 1' (see FIG. 8) and mixer 14. In the disclosed machines of FIGS. 1 and 8 only one additive at a time can be selectively added. However, with additional microswitches and one or more additional means for introducing an additive, which means is attached downstream of the injector and upstream of the mixer, a molded plastic article can be made having a foamed core without a colorant, a U.V. stabilizer, or the like, and an unfoamed skin containing a colorant or U.V. stabilizer, or the like.
In FIG. 2, there is disclosed a means for introducing a chemical blowing agent or other additive which is in the form of a dispersion. In pressure vessel 40, a dispersion 41 is forced under nitrogen pressure through tube 42 in which there are two valves 43 and 45. Valve 43 is a flow control valve and valve 45 is an on-off electrically controlled valve. There are two kinds of devices for introducing an additive into the molten thermoplastic material. The first is one which injects the blowing agent at the wall 44 of the tube just before the static mixer 14. This form of injection device is shown in FIG. 3. FIG. 2 discloses an in-stream injector comprising a ball valve 49 which prevents the molten thermoplastic material from passing into line 42, and a lower extension 47 which passes through the wall 44 of tube 46. To avoid plugging, holes 50 cause the exit direction of the additive to be in the downstream flow direction of the molten thermoplastic material. The holes 50 are arranged in two parallel rows each of five holes. Each pair of adjacent holes within a row are spaced apart by about 1/4 of an inch, and the rows are spaced apart by about 1/16 of an inch. The length of the in-stream injector 47 within tube 46 is about 11/4 inches. To aid mixing, the rows of holes 50 are positioned as shown in FIGS. 2 and 4 on either side of the leading edge of the first of a series of static mixer blades 52.
A measure of the amount of blowing agent added to a SSFC plastic article is the percent reduction in weight of the article which is equal to 100 TIMES (1-weight of the article with a foamed core/weight of the same article with a solid core). A percent reduction in weight between about 5-40% is typical for a plastic article of FIG. 5 having a solid skin 64 and a foamed core 62 with voids 60.
The quantity of blowing agent dispersion that is introduced into injected molten thermoplastic is determined by the pressure in vessel 40, the viscosity of the blowing agent dispersion 41, the diameter of tube 42, the flow permitted by control valve 43 and finally the length of time that on-off valve 45 is maintained in the open configuration. The nitrogen pressure must create sufficient pressure on the blowing agent dispersion so as to maintain the dispersion at a pressure greater than the pressure of the molten thermoplastic material at the point of introduction of the blowing agent into the molten thermoplastic material.
In FIG. 5, there is a swirl-free or unfoamed solid skin foamed core article having voids 60 in a core 62 and solid skin 64 as stated above. The presence or absence of swirl depends upon the thickness of the solid skin 64. The overall thickness of the solid skin depends upon the quantity of non-foamable thermoplastic resin injected at the beginning of the injection cycle.
In FIGS. 6 and 7, there is disclosed an additive 61 selectively added to the skin 64 and core 62, respectively.
EXAMPLE 1
A solid skin foamed core (SSFC) plastic article is injection molded in a step chip mold. The step chip mold is in the form of a series of equally long but increasingly wider steps of increasing thicknesses, i.e., 1/4"×10"×12", 3/8"×12"×12" and 1/2"×17"×12". The overall area of the flat bottom surface is 39"×12". The mold is cooled to a temperature of about 42° F. On the flat side, there are two gates adapted to receive standard 5/8 inch nozzles. One is located in the 1/4 inch thick section 11/2 inches from a 12 inch end side and 3 inches in from a 39 inch side. The other is in the 1/2 inch thick section 251/2 inches from said 12 inch end side and 3 inches in from said 39 inch side. The thickness of the foamed core and solid skin are approximately 9/64 and about 3/64 inch (opposite gate) or 4/64 inch (gate side) for the 1/4 inch section, 17/64 and 3/64 inch (opposite gate) or 4/64 inch (gate side) for the 3/8 inch section, and 22/64 inch and 3/64 inch (opposite gate) or 7/64 inch (gate side) for the 1/2 inch section, respectively.
Polystyrene having a flow rate of about 6.5 g/10 min. is extruded at a rate of 60 lbs./hr. The extruder has a two-stage screw size 31/2 inches in diameter rotating at a rate of 20 revolutions per minute. The temperature of the extruder is set for 450° F. The head pressure and temperature of the polystyrene is 2,700 psi and 500° F., respectively.
The polystyrene from the extruder moves under a pressure of about 2,700 psi through a pipe to an accumulator having an inside diameter of 7 inches. The barrel temperature of the accumulator is 500° F. Polystyrene is transferred to the accumulator until a cam on a piston arm of the accumulator activates a first microswitch. This indicates that the accumulator is full. If the mold is not ready the dump valve opens to remove excess plastic which cannot be injected into the mold. When the mold is ready then the valves or gates in a manifold are opened and polystyrene is injected into the step chip mold.
The speed of the injection shot is about 1 lb./second with a shot weight of 6 lbs. As the accumulator empties, molten polystyrene is ejected in a stream from the accumulator. The amount by weight of this molten stream plus that amount left in the system from the previous cycle determines the total amount by weight of N 2 -free polystyrene that forms the skin of the finished SSFC article. The distance between the first and second switches is set at 2.75 inches. This molten stream of polystyrene moves past the point for N 2 introduction (see FIG. 3) through the Kenics static mixer through a manifold and into a mold. While the proceeding is occurring a cam contacts a second microswitch thereby activating it. A signal is sent opening the valve to the means for introducing N 2 . With this valve open, N 2 under a pressure of about 3,000 psi is introduced into the molten stream of polystyrene which continues to be ejected from the accumulator. That portion of polystyrene passing the point of N 2 introduction when the valve is open has N 2 introduced therein. A static mixer downstream mixes or disperses the N 2 throughout said portion of polystyrene. This portion of polystyrene and N 2 exits from the mixer and flows through a manifold and into a mold. Introduction of N 2 into the molten polystyrene continues until the cam contacts a third microswitch which sends a signal closing the valve to the means for introducing N 2 . The distance between the second and third switches is set at 2.00 inches. This distance given the particular speed of the injection shot controls the amount by weight of the foamed core formed in the finished part.
After the third switch is activated, the subsequent stream of ejected polystyrene from the accumulator remains N 2 -free. It flows past the point of blowing agent introduction and through both the static mixer, and the manifold. A small portion thereof enters the mold "sealing" the gate area. As this subsequent stream moves toward the mold it pushes (flushes) all the polystyrene containing N 2 into the mold leaving only N 2 -free polystyrene between the point of N 2 introduction and the entrances to the mold. This flushing continues until the cam contacts a fourth microswitch which closes the gate to the mold. The distance between the third and fourth switches is set at 4.00 inches. The closing of the gate begins the refilling of the accumulator as molten polystyrene from the extruder flows into the accumulator. When the part has cooled sufficiently to be stable and handleable, it is removed from the mold. The empty mold is made ready for the next cycle of N 2 -free polystyrene to be injected into the mold.
A summary of the process conditions for this example is given in TABLE 1
TABLE 1______________________________________CONDITIONS TO FORM A FOAM CORE AND SOLIDSKIN ARTICLE USING POLYSTYRENE AND NITROGENWHERE NITROGEN IS INJECTED AT THE WALL______________________________________RESIN: PolystyreneFEED RATE: 60 lbs./hr.MOLD: Step Chip* Temperature: 42° F.EXTRUDER: Screw: two stage size 31/2" in diameter Rotation Rate of screw: 20 rpm Head pressure of plastic: 2700 psi Head temperature of plastic: 500° F. Temperature of extruder: 450° F.ACCUMULATOR: Barrel temperature: 500° F. Plastic pressure: 2700 psi Diameter: 7 inchesADDITIVE FEED: Pressure of N.sub.2 at point of feed: 3000 psiSWITCH SETTINGS: Switches Distances between switches 7-8 2.75" 8-9 2.00" 9-10 4.00"______________________________________ *Dimensions of mold are 39" × 12" with portions of 1/4" × 10" × 12", 3/8" × 12" × 12", and 1/2" × 17" × 12".
EXAMPLE 2
The same procedure as EXAMPLE 1, except that instead of N 2 , an azodicarbonamide dispersion is introduced at the wall. The finished part is about the same as EXAMPLE 1. The process conditions are given in TABLE 2.
The viscosity of the azodicarbonamide, in a 50% tris nonylphenyl phosphite dispersion, decreases with increasing temperature. During use, it is heated to about 180° F. Much below 180° F. the dispersion becomes too viscous to transfer. However, with decreasing viscosity the blowing agent has a significant tendency to settle out. Care must be exercised not to allow the dispersion to remain either unused or unstirred for more than one to two hours.
TABLE 2______________________________________CONDITIONS TO FORM A SOLID SKIN FOAM COREARTICLE USING POLYSTYRENE AND A CHEMICALBLOWING AGENT INJECTED AT THE WALL______________________________________RESIN: PolystyreneFEED RATE: 60 lbs/hr.MOLD: Step Chip (see TABLE 1) Temperature: 42° F.EXTRUDER: Screw: two stage size 31/2" in diameter Rotation Rate of screw: 20 rpm Head pressure of plastic: 2700 psi Head temperature of plastic: 500° F. Temperature of extruder: 450° F.ACCUMULATOR: Barrel temperature: 500° F. Plastic pressure: 2700 psi Diameter: 7 inchesADDITIVE FEED: *Blowing Agent: Azodicarbonamide dispersion Vessel pressure: 3000 psi Vessel temperature: 180° F.SWITCH SETTINGS: - See Table 1.______________________________________ *Azodicarbonamide, Celogen AZ, obtainable from Uniroyal Chemical, Naugatuck, Conn., is in a 50% dispersion of tris nonylphenyl phosphite, Wytox 312, obtainable from Stephen Chemicals.
EXAMPLE 3
The same procedure as followed in EXAMPLE 1, except that instead of injecting the N 2 at the wall an in-stream injector (see FIG. 2) is used, and instead of polystyrene, polyethylene having a melt index of about 5.5 g/10 minutes is used. The results are about the same as EXAMPLE 1. The process conditions for this Example are given in TABLE 3.
TABLE 3______________________________________CONDITIONS TO FORM A SOLID SKIN FOAM COREARTICLE USING POLYETHYLENE AND A BLOWINGAGENT INTRODUCED BY MEANS OF AN INSTREAMINJECTOR______________________________________RESIN: PolyethyleneFEED RATE: 54 lbs/hr.MOLD: Step Chip (see TABLE 1) Temperature: 42° F.EXTRUDER: Screw: two stage size 31/2" in diameter Rotation Rate of Screw: 21 rpm Head pressure of plastic: 2800 psi Head temperature of plastic: 500° F. Temperature of extruder: 450° F.ACCUMULATOR: Barrel temperature: 500° F. Plastic pressure: 2700 psi Diameter: 7 inchesBLOWING AGENTFEED: Blowing Agent: N.sub.2 N.sub.2 pressure: 3000 psi. -SWITCH SETTINGS: See Table 1______________________________________
EXAMPLE 4
In this example a molded plastic step chip is formed wherein a dye dispersion of blue Liqui-kolor, obtainable from Inmont Corporation, Chicago, Ill., is selectively introduced only into the skin.
About 10 lbs. of a dye dispersion of blue Liqui-Kolor is introduced into a pressurizable vessel. The viscosity is adjusted by the addition of tris nonylphenyl phosphite, Wytox 312. A pressure of about 3,000 psi is applied by compressed N 2 . The pressure vessel is connected to an in-stream injector. A single on-off solenoid valve and one way valve control the flow of the dye dispersion from the vessel into the in-stream injector.
The same mold and mold temperatures as EXAMPLE 1 are used.
Polyethylene having a melt index of about 5.5 g/10 minutes is extruded at a rate of 54 lbs./hr. under a pressure and temperature at the head of the extruder of 2,800 psi and 500° F., respectively, from an extruder having a two stage screw with a diameter of about 31/2 inches rotating 21 revolutions per minute and set to have a barrel temperature of 450° F.
The polyethylene from the above extruder is fed into an accumulator having a barrel temperature of 500° F. with a diameter of 7 inches wherein a back-pressure of about 2,700 psi is maintained.
When a cam on the piston of said accumulator activates a first microswitch this signals that the accumulator is full and if the mold is ready, three valves are opened simultaneously. These are the two valves to the gates of the step chip mold and the on-off valve between the pressure vessel and the in-stream injector.
A molten polyethylene is ejected in a stream at a rate of about 1 lb./sec. As said stream passes the in-stream injector, the dye dispersion is introduced therein, and as said stream with dye therein passes through a Kenics static mixer, the dye is dispersed uniformly throughout. Said on-off valve is closed when said cam activates a second microswitch 2.75 inches from said first microswitch. The subsequent molten polyethylene ejected in a stream from the accumulator, which passes the in-stream injector after the on-off valve is closed, does not have dye introduced therein. This subsequent stream continues past the in-stream injector through the Kenics mixer and into the mold. All polyethylene having dye within is thereby flushed from the system into the mold. The amount by weight of dye-free polyethylene in said subsequent stream will determine the weight of the core formed in the finished molded article. The on-off valve remains closed until a third microswitch is activated. This third microswitch is set 2.00 inches from said second microswitch. The final portion in a stream of ejected polyethylene which passes the in-stream injector while the on-off valve is open has dye introduced therein. As this final portion passes through the Kenics mixer toward the mold gates it replaces all dye-free polyethylene from between the point of dye introduction to these mold gates. A small amount of this final portion containing dye enters the mold to "seal" the gate area. Finally, a fourth microswitch is activated which simultaneously closes the two gate valves and the on-off valve to the dye dispersion. The distance between said third and fourth microswitches is set at 4.00 inches. With the mold gates closed the accumulator begins to fill for the next injection cycle.
When the molded article has sufficiently cooled, it is removed from the mold and the mold is made ready for the next cycle. The total time for one complete cycle is about 12 seconds.
EXAMPLE 5
In this example, the procedure of EXAMPLE 4 and the process conditions shown in TABLE 2 are used except that in place of a blowing agent dispersion, a 25% flame retardant additive consisting of 2 parts decabromodiphenyl oxide to 1 part Sb 2 O 3 in tris nonylphenyl phosphite, Wytox 312 is used.
It is to be noted that the usual latitude as to temperature and time is made possible with the disclosed process. However, when prior art processes were employed, the molding temperature of the plastic had to be held to about 470° F. and time consuming purging is required to avoid degradation of the fire retardant additive.
The examples disclosed are intended to be illustrative only and variations are readily apparent to those skilled in the art based upon the teachings herein and are within the scope of the intended invention. | A method for injection molding an article wherein additives are selectively introduced into the polymer melt downstream of an accumulation device and upstream of a static mixer just prior to its introduction into the mold cavity. The additives include U.V. stabilizers, flame retardant materials, colorants and blowing agents. The method produces injection molded articles with selective amounts of additives in either the skin or core portions of the articles. | Briefly describe the main invention outlined in the provided context. | [
"This is a division, of application Ser.",
"No. 692,339, filed June 3, 1976 now U.S. Pat. No. 4,135,870.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention This invention is directed to an improvement in the art of forming foamed and unfoamed molded plastic articles.",
"Description of the Prior Art "Additives"",
"throughout this Specification and Claims are defined to mean substances or materials added to thermoplastic resins.",
"Examples of such additives are flame retardants, U.V. stabilizers, blowing agents, colorants, etc.",
"Examples of thermoplastic resins useful in this invention are polyethylene, polypropylene, polystyrene, polyvinyl chloride, copolymers thereof and the like.",
"In general, any injection moldable thermoplastic resin can be used.",
"The following, for purposes of discussion, considers prior art relating to blowing agent additives.",
"Prior methods and apparatus for adding blowing agents to a plastic resin to form solid skin and foamed core (SSFC) articles are exemplified in the patents to De Vita, U.S. Pat. No. 3,746,492 (1973), D. F. Oxley, U.S. Pat. No. 3,751,534 (1973), P. J. Garner and D. F. Oxley, U.K. Pat. No. 1,156,217 (1969), and R. G. Angell, Jr. U.S. Pat. No. 3,436,446 (1969).",
"In each of the above cited art, a blowing agent is introduced into a thermoplastic material to form a foamable plastic mixture.",
"This mixture is then accumulated under pressure in an accumulator or an injector.",
"An injector is used throughout this Specification and Claims to mean a device capable of both accumulating and injecting under pressure molten plastic into a mold.",
"Some examples of injectors are the accumulators disclosed in the above cited art and reciprocating screw or plunger injection molding machines such as sold by Cincinnati Milacron.",
"One known method for injecting foamable and unfoamable plastic material alternately into a mold involves the use of two coupled injection systems, one for foamable and the other for unfoamable plastic materials.",
"These systems are arranged to inject alternately through a single nozzle.",
"Another known method uses a single injection system containing discrete layers of foamable and unfoamable plastic material.",
"Upon injection, each discrete layer enters the mold separately, thereby injecting alternately in a single injection stroke foamable and unfoamable plastic into a mold.",
"There are several disadvantages inherent to these known methods.",
"In the case where two injection systems are required, there are the substantial equipment costs and the need during filling for back-pressures in one of the injector systems to prevent premature foaming.",
"Similarly, in the case where a single injection system employs discrete layers of foamable and unfoamable plastic, back-pressures on the foamable plastic material is required prior to injection in order to prevent premature foaming.",
"In general, process control is more difficult where back-pressures are necessary.",
"Further where an additive other than a blowing agent is added to a molten plastic before the molten plastic material is accumulated in an accumulator, degradation of said material often occurs to such a degree as to preclude the use of many otherwise useful additives.",
"H. L. Maiocco, U.S. Pat. No. 3,817,675 (1974) discloses an apparatus for introducing a measured quantity of colorants into a plasticized plastic stream just downstream of an extruder and just upstream of a mixer.",
"This apparatus is similar to De Vita ('492) in that in De Vita a blowing agent instead of a colorant is introduced just downstream of an extruder and just upstream of a mixer.",
"Maiocco ('675) as disclosed has several limitations.",
"There is no provision for selectively adding colorants to a plasticized plastic.",
"There is no discussion concerning the addition of blowing agents, U.V. stabilizers or flame retardants.",
"There is not disclosed the substitution of an injector for an extruder.",
"That there is no means disclosed for selectively adding colorants makes a process of selectively introducing additives either into the skin or core of a molded plastic article very difficult to achieve.",
"Since the substitution of an injector with its accumulation zone for an extruder is not disclosed, there is not taught a practical means for injecting in a periodic flow the quantities of a plasticized plastic often required during an injection molding cycle.",
"BRIEF DESCRIPTION OF THE INVENTION In one embodiment, the invention comprises the utilization of a machine for producing foamed core and foamed or unfoamed solid skin molded plastic articles.",
"A unique feature of this machine over that disclosed in the above cited prior art resides in the time and location of introducing an additive into a molten plastic.",
"The time for the introduction of the additive in this invention is during the injection of molten plastic, and the location is downstream of an injector.",
"The steps for introducing molten plastic material into a mold is as follows: (1) ejecting a molten plastic from an injector to form a stream, (2) introducing selectively an additive into said stream, (3) mixing the product of step (2), and (4) flushing out any additive-containing plastic between the point of introducing said additive and the mold entrance.",
"The details of the step of flushing will be discussed later.",
"This sequence of events is determined by a series of switches activated as a piston of an accumulator or an injector moves through "activation points"",
"or "activation positions"",
"during the emptying of said accumulator or injector.",
"The timing and duration of each of the above events is determined by the rate of motion of said piston and distance between these activation points.",
"The total time for steps (1) to (4) requires a maximum of approximately 30 seconds.",
"The total cycle time depends upon several factors known to a man of skill in the art.",
"In another embodiment, the sequence of steps for introducing a material into a molded plastic article is (1) melting a thermoplastic resin, (2) transferring said thermoplastic resin to any accumulation zone where it is maintained in a molten state, (3) ejecting said resin from said accumulation zone to form a molten plastic stream, (4) introducing into said stream an additive, (5) mixing said additive and said stream to form a mixture thereof, and (6) channelling said mixture into a mold.",
"One or more mixers downstream from the accumulation zone of an injector insure uniform dispersion of the additive throughout the molten plastic.",
"A measure of the efficiency of a mixer can be determined based upon the cell structure of the foamed plastic.",
"Further, since the rate at which a molten plastic will fill a mold is dependent in part upon the pressure imposed upon said plastic, and since a pressure drop necessarily will result from the plastic flowing through one or more mixers prior to entering the mold, care must be exercised so that the pressure on the plastic at the point of injection into the mold is sufficient to insure rapid transfer of the plastic from the accumulator or injector into the mold.",
"In the above discussion, additive was used generically, but for purposes of clarity an example dealing with a blowing agent as an additive will be considered.",
"One of the machines in this case can produce SSFC articles.",
"To understand the operation of this machine, a discussion of four switches contained therein is necessary.",
"A first switch signals that the injector is full and ready to begin filling the mold with plastic and a last switch closes a nozzle or gate to a mold.",
"A second switch opens and a third closes a valve in a means for introducing a blowing agent into the ejected molten plastic.",
"The distance between activation points for the first and second switches influences the amount by weight of unfoamable plastic which is injected into the mold before a blowing agent is introduced into the molten plastic.",
"This initial shot of unfoamable plastic will influence the amount by weight of unfoamed skin on a finished part.",
"The distance between the activation points for the second and third switches determines the amount by weight of foamed core formed in a resulting plastic part.",
"The distance between the activation points for the third and fourth switches controls the process of flushing.",
"The distance between the activation points of the third and fourth switches is adjusted to insure that sufficient unfoamable plastic is injected through the mixer and nozzle manifold so that all feed channels between the point of blowing agent introduction and the mold entrances are filled with unfoamable plastic and optionally, so that a final portion of plastic introduced into the mold is unfoamable.",
"If flushing is complete, then the initial injection into the mold for the next part will be only unfoamable plastic.",
"It is to be noted that pairwise the first and second, and the third and fourth switches can be combined.",
"The result of combining switches is to provide a machine capable of uniformly distributing an additive throughout both the core and skin of a molded plastic article.",
"The blowing agent introduced into the molten plastic material may be either chemical or physical.",
"Examples of physical blowing agents are compounds which are or become gaseous due to a change in physical state.",
"Examples of such compounds are compressed air, nitrogen, pentane, hexane, etc.",
"Examples of chemical blowing agents are substances which decompose giving rise to gases.",
"Examples of such substances are azo compounds, semicarbazides, azides, diazoamino compounds, etc.",
"In the case of a chemical blowing agent dispersion, the most efficient mixing occurs when the viscosity of the chemical blowing agent dispersion is comparable to that of the molten plastic material.",
"The quantity of chemical blowing agent dispersion introduced for a given period of time is determined by the pressure imposed upon and the resistance to flow of the chemical blowing agent dispersion.",
"The flow rate of chemical blowing agent from a reservoir through a tube into a molten plastic material is controlled by two valves one a precision needle valve or other flow controlling means and the other an on-off valve such as an electrically controlled solenoid.",
"In a more generalized form, the invention comprises a method for introducing an additive into a molten plastic.",
"Previously, the introducing of a blowing agent into a portion of injected molten plastic was considered.",
"In a similar manner, additives such as U.V. stabilizers, flame retardants, and colorants can be introduced selectively so that they become part of either the skin and/or the core of a finished molded article.",
"There are several reasons for introducing additives downstream of the injector in the manner disclosed;",
"for example, the location of the additive in the core and/or in the skin of the finished molded article can be readily controlled;",
"the length of time said additive is subjected to high temperatures and pressures is considerably reduced over cited art methods;",
"and back-pressures such as discussed in the patent to De Vita ('492) during the filling of an accumulator or injector can be avoided.",
"In general, colorants', flame retardants', and U.V. stabilizers'",
"effectiveness is directly proportional to their concentration at or near the surface.",
"Therefore, greater effectiveness for a given weight of such additives will occur if it is concentrated at or close to the surface rather than uniformly distributed throughout the molded plastic article.",
"Further, as an additional advantage, the use of pigments selectively at the surface of a thick structural foam article permits the use of less pigment with a resulting savings in pigment costs.",
"It is an object of this invention to provide the utilization of a machine for introducing additives downstream of an injector.",
"It is an object of this invention to provide the utilization of a machine capable with minor adjustments of producing either swirl or swirl-free foamed core molded plastic articles.",
"It is an object of this invention to provide a method for using many additives which cannot otherwise be used in producing injection molded plastic articles.",
"It is an object of this invention to provide a method for selectively introducing additives either into the skin or core of a molded plastic article.",
"Other objects of this invention will be clear to a man of average skill in the art once the teachings of this Application are disclosed.",
"DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a schematic diagram of an apparatus to add an additive such as a blowing agent to a molded plastic article.",
"FIG. 2 is the apparatus used to introduce a chemical blowing agent in the form of a dispersion into the molten plastic stream downstream of an injector and upstream of a mixer as viewed along line 2--2 of FIGS. 1 and 8.",
"FIG. 3 is the apparatus used to introduce a chemical or gaseous blowing agent at a wall downstream of an injector and upstream of a mixer.",
"FIG. 4 is a view along section line 4--4 of FIGS. 1 and 8.",
"FIG. 5 is a cross-section of a swirl-free SSFC thermoplastic article.",
"FIGS. 6 and 7 are cross-sectional views of molded plastic articles wherein an additive has been selectively added to the skin and core of each, respectively.",
"FIG. 8 is a schematic view of a portion of the machine of FIG. 1 wherein the extruder and accumulator have been replaced by a reciprocating screw injection molding machine.",
"The elements comprising the apparatus disclosed in FIG. 1 are an extruder 1, a passageway 24 between extruder 1 and an accumulator 12, a dump valve 2, a piston-activating means comprising a cylinder 5 having inlets and outlets 4 and 6, a conduit 13 for introducing an additive, a mixer 14, an injection nozzle manifold 15 and a series of microswitches 7, 8, 9, and 10.",
"Thermoplastic material (not shown) at the upstream end is fed into hopper 3 at a rate dependent upon cycle time.",
"This material is melted and leaves the extruder at a temperature of about 325°-800° F. The amount of pressure by which the pressure on the plastic at the extruder head exceeds the back-pressure of the accumulator 12 can vary depending upon the plastic being processed.",
"For example, if high shear is required either for mechanical heating or mixing then the amount of the excess pressure is above 500 psi.",
"If on the other hand low shear is required to prevent undesirable mechanical heating then the amount of the excess pressure is below 500 psi.",
"The extruded thermoplastic material moves through passageway 24 to an accumulator 12.",
"The accumulator 12 of FIG. 1 is in its emptied configuration so that as thermoplastic material moves from the extruder 1 to the accumulator 12 piston arm 25 moves to the left and accumulator 12 becomes filled with molten thermoplastic material.",
"During filling of the accumulator 12, a back-pressure is maintained on the piston.",
"The injection cycle beginning with the emptying of accumulator 12 involves the following sequence: (1) just as accumulator 12 is completely filled, cam 11 activates a first microswitch 7 which signals that the accumulator is full and ready to begin filling the mold with plastic.",
"In the event that a longer time than usual is required to ready the mold for the next injection of plastic, then either excess plastic from extruder 1 exits out through dump valve 2 or in the absence of dump valve 2, the screw of extruder 1 is stopped.",
"When the mold is ready a valve (not shown) in the manifold 15 opens and molten plastic is injected from accumulator 12 past a point for introducing an additive, through mixer 14 containing mixer elements 52, into manifold 15 and then into a mold means 17-23;",
"(2) cam 11 activates a second microswitch 8 which opens valve 45, thereby introducing into said injected molten plastic an additive prior to mixer 14 and downstream of accumulator 12;",
"(3) cam 11 activates a third micro switch 9 which closes valve 45 thereby stopping the introduction of any more additive;",
"and (4) cam 11 activates a fourth microswitch 10 which closes manifold 15 and the accumulator 12 begins to fill for the next cycle.",
"It is to be noted that the on-off periods for the valve in the means for introducing an additive can be changed as in EXAMPLES 4 and 5 so that the additive is introduced into an exterior portion of the stream of molten plastic ejected from an injector, i.e., selectively introduced into the skin of a finished molded article.",
"It is further to be noted that pairwise the first and second, and the third and fourth microswitches can be combined into two switches when it is desired to have the additive introduced both into the skin and core of the finished molded article.",
"The portion of the injection process which will hereinafter be referred to as the step of flushing is determined by the distance between microswitches 9 and 10.",
"The step of flushing insures that all thermoplastic material containing any additive between the point of injection for such additives and the mold entrance points 31 and 32 is replaced by additive-free thermoplastic material.",
"Optionally, additive-free molten plastic can be introduced as the last portion of plastic to enter the mold at the end of the injection cycle to "seal"",
"the gate area.",
"If the flushing is not complete, then during the next injection cycle there will be some additive in the thermoplastic material in a portion of the skin of the molded plastic article formed.",
"If the additive being considered is a blowing agent, then a swirly surface will result.",
"Where there is a division point 30 which has several paths therefrom to a mold, care must be exercised as to the step of flushing because generally a different rate of flow of the thermoplastic material will occur within the different paths available.",
"The difference in flow rate along these various paths to the mold cavity is a function of (1) the differences in resistance to flow caused by variations in diameter, and/or length of each path to the mold and (2) the differences in resistance to flow from each path through a particular mold gate as a result of the geometry of the mold.",
"As a general rule of thumb, to insure roughly equivalent flow rates through the various paths, the pressure drop between the division point 30 to each of the injection points 31 and 32 should be substantially the same.",
"Another way to insure complete removal of additive containing plastic material is to have a separate injector for each injection point.",
"Mixer 14 having a plurality of variously oriented mixer blades 52 provides very efficient mixing of injected thermoplastic material and an added blowing agent or other additive and does not decrease the pressure at the injection points 31 and 32 below about 200 psi.",
"We have found that a static mixer by Kenics Corporation of Danvers, Massachusetts affords sufficient mixing and a pressure drop between the accumulator head and distribution point 30 of approximately 3-5 times that pressure drop caused by a tube of the same length and diameter as that enclosing the mixer but without any mixer elements or blades 52.",
"Several modifications to FIGS. 1 and 8 in keeping with this invention are: that dump valve 2 may be eliminated if microswitch 7 when activated will stop either the screw of extruder 1 or the reciprocating screw of the injection molding machine 1', that additional microswitches can be added, and that one or more additional means for introducing an additive can be attached to a passageway connecting accumulator 12 or reciprocating screw injector 1'",
"(see FIG. 8) and mixer 14.",
"In the disclosed machines of FIGS. 1 and 8 only one additive at a time can be selectively added.",
"However, with additional microswitches and one or more additional means for introducing an additive, which means is attached downstream of the injector and upstream of the mixer, a molded plastic article can be made having a foamed core without a colorant, a U.V. stabilizer, or the like, and an unfoamed skin containing a colorant or U.V. stabilizer, or the like.",
"In FIG. 2, there is disclosed a means for introducing a chemical blowing agent or other additive which is in the form of a dispersion.",
"In pressure vessel 40, a dispersion 41 is forced under nitrogen pressure through tube 42 in which there are two valves 43 and 45.",
"Valve 43 is a flow control valve and valve 45 is an on-off electrically controlled valve.",
"There are two kinds of devices for introducing an additive into the molten thermoplastic material.",
"The first is one which injects the blowing agent at the wall 44 of the tube just before the static mixer 14.",
"This form of injection device is shown in FIG. 3. FIG. 2 discloses an in-stream injector comprising a ball valve 49 which prevents the molten thermoplastic material from passing into line 42, and a lower extension 47 which passes through the wall 44 of tube 46.",
"To avoid plugging, holes 50 cause the exit direction of the additive to be in the downstream flow direction of the molten thermoplastic material.",
"The holes 50 are arranged in two parallel rows each of five holes.",
"Each pair of adjacent holes within a row are spaced apart by about 1/4 of an inch, and the rows are spaced apart by about 1/16 of an inch.",
"The length of the in-stream injector 47 within tube 46 is about 11/4 inches.",
"To aid mixing, the rows of holes 50 are positioned as shown in FIGS. 2 and 4 on either side of the leading edge of the first of a series of static mixer blades 52.",
"A measure of the amount of blowing agent added to a SSFC plastic article is the percent reduction in weight of the article which is equal to 100 TIMES (1-weight of the article with a foamed core/weight of the same article with a solid core).",
"A percent reduction in weight between about 5-40% is typical for a plastic article of FIG. 5 having a solid skin 64 and a foamed core 62 with voids 60.",
"The quantity of blowing agent dispersion that is introduced into injected molten thermoplastic is determined by the pressure in vessel 40, the viscosity of the blowing agent dispersion 41, the diameter of tube 42, the flow permitted by control valve 43 and finally the length of time that on-off valve 45 is maintained in the open configuration.",
"The nitrogen pressure must create sufficient pressure on the blowing agent dispersion so as to maintain the dispersion at a pressure greater than the pressure of the molten thermoplastic material at the point of introduction of the blowing agent into the molten thermoplastic material.",
"In FIG. 5, there is a swirl-free or unfoamed solid skin foamed core article having voids 60 in a core 62 and solid skin 64 as stated above.",
"The presence or absence of swirl depends upon the thickness of the solid skin 64.",
"The overall thickness of the solid skin depends upon the quantity of non-foamable thermoplastic resin injected at the beginning of the injection cycle.",
"In FIGS. 6 and 7, there is disclosed an additive 61 selectively added to the skin 64 and core 62, respectively.",
"EXAMPLE 1 A solid skin foamed core (SSFC) plastic article is injection molded in a step chip mold.",
"The step chip mold is in the form of a series of equally long but increasingly wider steps of increasing thicknesses, i.e., 1/4"×10"×12", 3/8"×12"×12"",
"and 1/2"×17"×12".",
"The overall area of the flat bottom surface is 39"×12".",
"The mold is cooled to a temperature of about 42° F. On the flat side, there are two gates adapted to receive standard 5/8 inch nozzles.",
"One is located in the 1/4 inch thick section 11/2 inches from a 12 inch end side and 3 inches in from a 39 inch side.",
"The other is in the 1/2 inch thick section 251/2 inches from said 12 inch end side and 3 inches in from said 39 inch side.",
"The thickness of the foamed core and solid skin are approximately 9/64 and about 3/64 inch (opposite gate) or 4/64 inch (gate side) for the 1/4 inch section, 17/64 and 3/64 inch (opposite gate) or 4/64 inch (gate side) for the 3/8 inch section, and 22/64 inch and 3/64 inch (opposite gate) or 7/64 inch (gate side) for the 1/2 inch section, respectively.",
"Polystyrene having a flow rate of about 6.5 g/10 min.",
"is extruded at a rate of 60 lbs.",
"/hr.",
"The extruder has a two-stage screw size 31/2 inches in diameter rotating at a rate of 20 revolutions per minute.",
"The temperature of the extruder is set for 450° F. The head pressure and temperature of the polystyrene is 2,700 psi and 500° F., respectively.",
"The polystyrene from the extruder moves under a pressure of about 2,700 psi through a pipe to an accumulator having an inside diameter of 7 inches.",
"The barrel temperature of the accumulator is 500° F. Polystyrene is transferred to the accumulator until a cam on a piston arm of the accumulator activates a first microswitch.",
"This indicates that the accumulator is full.",
"If the mold is not ready the dump valve opens to remove excess plastic which cannot be injected into the mold.",
"When the mold is ready then the valves or gates in a manifold are opened and polystyrene is injected into the step chip mold.",
"The speed of the injection shot is about 1 lb.",
"/second with a shot weight of 6 lbs.",
"As the accumulator empties, molten polystyrene is ejected in a stream from the accumulator.",
"The amount by weight of this molten stream plus that amount left in the system from the previous cycle determines the total amount by weight of N 2 -free polystyrene that forms the skin of the finished SSFC article.",
"The distance between the first and second switches is set at 2.75 inches.",
"This molten stream of polystyrene moves past the point for N 2 introduction (see FIG. 3) through the Kenics static mixer through a manifold and into a mold.",
"While the proceeding is occurring a cam contacts a second microswitch thereby activating it.",
"A signal is sent opening the valve to the means for introducing N 2 .",
"With this valve open, N 2 under a pressure of about 3,000 psi is introduced into the molten stream of polystyrene which continues to be ejected from the accumulator.",
"That portion of polystyrene passing the point of N 2 introduction when the valve is open has N 2 introduced therein.",
"A static mixer downstream mixes or disperses the N 2 throughout said portion of polystyrene.",
"This portion of polystyrene and N 2 exits from the mixer and flows through a manifold and into a mold.",
"Introduction of N 2 into the molten polystyrene continues until the cam contacts a third microswitch which sends a signal closing the valve to the means for introducing N 2 .",
"The distance between the second and third switches is set at 2.00 inches.",
"This distance given the particular speed of the injection shot controls the amount by weight of the foamed core formed in the finished part.",
"After the third switch is activated, the subsequent stream of ejected polystyrene from the accumulator remains N 2 -free.",
"It flows past the point of blowing agent introduction and through both the static mixer, and the manifold.",
"A small portion thereof enters the mold "sealing"",
"the gate area.",
"As this subsequent stream moves toward the mold it pushes (flushes) all the polystyrene containing N 2 into the mold leaving only N 2 -free polystyrene between the point of N 2 introduction and the entrances to the mold.",
"This flushing continues until the cam contacts a fourth microswitch which closes the gate to the mold.",
"The distance between the third and fourth switches is set at 4.00 inches.",
"The closing of the gate begins the refilling of the accumulator as molten polystyrene from the extruder flows into the accumulator.",
"When the part has cooled sufficiently to be stable and handleable, it is removed from the mold.",
"The empty mold is made ready for the next cycle of N 2 -free polystyrene to be injected into the mold.",
"A summary of the process conditions for this example is given in TABLE 1 TABLE 1______________________________________CONDITIONS TO FORM A FOAM CORE AND SOLIDSKIN ARTICLE USING POLYSTYRENE AND NITROGENWHERE NITROGEN IS INJECTED AT THE WALL______________________________________RESIN: PolystyreneFEED RATE: 60 lbs.",
"/hr.",
"MOLD: Step Chip* Temperature: 42° F.EXTRUDER: Screw: two stage size 31/2"",
"in diameter Rotation Rate of screw: 20 rpm Head pressure of plastic: 2700 psi Head temperature of plastic: 500° F. Temperature of extruder: 450° F.ACCUMULATOR: Barrel temperature: 500° F. Plastic pressure: 2700 psi Diameter: 7 inchesADDITIVE FEED: Pressure of N.sub[.",
"].2 at point of feed: 3000 psiSWITCH SETTINGS: Switches Distances between switches 7-8 2.75"",
"8-9 2.00"",
"9-10 4.00"______________________________________ *Dimensions of mold are 39"",
"× 12"",
"with portions of 1/4"",
"× 10"",
"× 12", 3/8"",
"× 12"",
"× 12", and 1/2"",
"× 17"",
"× 12".",
"EXAMPLE 2 The same procedure as EXAMPLE 1, except that instead of N 2 , an azodicarbonamide dispersion is introduced at the wall.",
"The finished part is about the same as EXAMPLE 1.",
"The process conditions are given in TABLE 2.",
"The viscosity of the azodicarbonamide, in a 50% tris nonylphenyl phosphite dispersion, decreases with increasing temperature.",
"During use, it is heated to about 180° F. Much below 180° F. the dispersion becomes too viscous to transfer.",
"However, with decreasing viscosity the blowing agent has a significant tendency to settle out.",
"Care must be exercised not to allow the dispersion to remain either unused or unstirred for more than one to two hours.",
"TABLE 2______________________________________CONDITIONS TO FORM A SOLID SKIN FOAM COREARTICLE USING POLYSTYRENE AND A CHEMICALBLOWING AGENT INJECTED AT THE WALL______________________________________RESIN: PolystyreneFEED RATE: 60 lbs/hr.",
"MOLD: Step Chip (see TABLE 1) Temperature: 42° F.EXTRUDER: Screw: two stage size 31/2"",
"in diameter Rotation Rate of screw: 20 rpm Head pressure of plastic: 2700 psi Head temperature of plastic: 500° F. Temperature of extruder: 450° F.ACCUMULATOR: Barrel temperature: 500° F. Plastic pressure: 2700 psi Diameter: 7 inchesADDITIVE FEED: *Blowing Agent: Azodicarbonamide dispersion Vessel pressure: 3000 psi Vessel temperature: 180° F.SWITCH SETTINGS: - See Table 1.",
"______________________________________ *Azodicarbonamide, Celogen AZ, obtainable from Uniroyal Chemical, Naugatuck, Conn.",
", is in a 50% dispersion of tris nonylphenyl phosphite, Wytox 312, obtainable from Stephen Chemicals.",
"EXAMPLE 3 The same procedure as followed in EXAMPLE 1, except that instead of injecting the N 2 at the wall an in-stream injector (see FIG. 2) is used, and instead of polystyrene, polyethylene having a melt index of about 5.5 g/10 minutes is used.",
"The results are about the same as EXAMPLE 1.",
"The process conditions for this Example are given in TABLE 3.",
"TABLE 3______________________________________CONDITIONS TO FORM A SOLID SKIN FOAM COREARTICLE USING POLYETHYLENE AND A BLOWINGAGENT INTRODUCED BY MEANS OF AN INSTREAMINJECTOR______________________________________RESIN: PolyethyleneFEED RATE: 54 lbs/hr.",
"MOLD: Step Chip (see TABLE 1) Temperature: 42° F.EXTRUDER: Screw: two stage size 31/2"",
"in diameter Rotation Rate of Screw: 21 rpm Head pressure of plastic: 2800 psi Head temperature of plastic: 500° F. Temperature of extruder: 450° F.ACCUMULATOR: Barrel temperature: 500° F. Plastic pressure: 2700 psi Diameter: 7 inchesBLOWING AGENTFEED: Blowing Agent: N.sub[.",
"].2 N.sub[.",
"].2 pressure: 3000 psi.",
"-SWITCH SETTINGS: See Table 1______________________________________ EXAMPLE 4 In this example a molded plastic step chip is formed wherein a dye dispersion of blue Liqui-kolor, obtainable from Inmont Corporation, Chicago, Ill.",
", is selectively introduced only into the skin.",
"About 10 lbs.",
"of a dye dispersion of blue Liqui-Kolor is introduced into a pressurizable vessel.",
"The viscosity is adjusted by the addition of tris nonylphenyl phosphite, Wytox 312.",
"A pressure of about 3,000 psi is applied by compressed N 2 .",
"The pressure vessel is connected to an in-stream injector.",
"A single on-off solenoid valve and one way valve control the flow of the dye dispersion from the vessel into the in-stream injector.",
"The same mold and mold temperatures as EXAMPLE 1 are used.",
"Polyethylene having a melt index of about 5.5 g/10 minutes is extruded at a rate of 54 lbs.",
"/hr.",
"under a pressure and temperature at the head of the extruder of 2,800 psi and 500° F., respectively, from an extruder having a two stage screw with a diameter of about 31/2 inches rotating 21 revolutions per minute and set to have a barrel temperature of 450° F. The polyethylene from the above extruder is fed into an accumulator having a barrel temperature of 500° F. with a diameter of 7 inches wherein a back-pressure of about 2,700 psi is maintained.",
"When a cam on the piston of said accumulator activates a first microswitch this signals that the accumulator is full and if the mold is ready, three valves are opened simultaneously.",
"These are the two valves to the gates of the step chip mold and the on-off valve between the pressure vessel and the in-stream injector.",
"A molten polyethylene is ejected in a stream at a rate of about 1 lb.",
"/sec.",
"As said stream passes the in-stream injector, the dye dispersion is introduced therein, and as said stream with dye therein passes through a Kenics static mixer, the dye is dispersed uniformly throughout.",
"Said on-off valve is closed when said cam activates a second microswitch 2.75 inches from said first microswitch.",
"The subsequent molten polyethylene ejected in a stream from the accumulator, which passes the in-stream injector after the on-off valve is closed, does not have dye introduced therein.",
"This subsequent stream continues past the in-stream injector through the Kenics mixer and into the mold.",
"All polyethylene having dye within is thereby flushed from the system into the mold.",
"The amount by weight of dye-free polyethylene in said subsequent stream will determine the weight of the core formed in the finished molded article.",
"The on-off valve remains closed until a third microswitch is activated.",
"This third microswitch is set 2.00 inches from said second microswitch.",
"The final portion in a stream of ejected polyethylene which passes the in-stream injector while the on-off valve is open has dye introduced therein.",
"As this final portion passes through the Kenics mixer toward the mold gates it replaces all dye-free polyethylene from between the point of dye introduction to these mold gates.",
"A small amount of this final portion containing dye enters the mold to "seal"",
"the gate area.",
"Finally, a fourth microswitch is activated which simultaneously closes the two gate valves and the on-off valve to the dye dispersion.",
"The distance between said third and fourth microswitches is set at 4.00 inches.",
"With the mold gates closed the accumulator begins to fill for the next injection cycle.",
"When the molded article has sufficiently cooled, it is removed from the mold and the mold is made ready for the next cycle.",
"The total time for one complete cycle is about 12 seconds.",
"EXAMPLE 5 In this example, the procedure of EXAMPLE 4 and the process conditions shown in TABLE 2 are used except that in place of a blowing agent dispersion, a 25% flame retardant additive consisting of 2 parts decabromodiphenyl oxide to 1 part Sb 2 O 3 in tris nonylphenyl phosphite, Wytox 312 is used.",
"It is to be noted that the usual latitude as to temperature and time is made possible with the disclosed process.",
"However, when prior art processes were employed, the molding temperature of the plastic had to be held to about 470° F. and time consuming purging is required to avoid degradation of the fire retardant additive.",
"The examples disclosed are intended to be illustrative only and variations are readily apparent to those skilled in the art based upon the teachings herein and are within the scope of the intended invention."
] |
FIELD OF THE INVENTION
[0001] The invention relates to the field of microbial enhanced oil recovery and bioremediation of subterranean contaminated sites. Specifically, it relates to methods of treating the toxic chemicals accumulated in subterranean sites adjacent to the water injection wells prior to introduction of microbial inocula for microbial enhanced oil recovery or bioremediation of these sites.
BACKGROUND OF THE INVENTION
[0002] Traditional oil recovery techniques which utilize only the natural forces present at an oil well site, allow recovery of only a minor portion of the crude oil present in an oil reservoir. Oil well site generally refers to any location where wells have been drilled into a subterranean rock containing oil with the intent to produce oil from that subterranean rock. An oil reservoir typically refers a deposit of subterranean oil. Supplemental recovery methods such as water flooding have been used to force oil through the subterranean location toward the production well and thus improve recovery of the crude oil (Hyne, N.J., 2001, “Non-technical guide to petroleum geology, exploration, drilling, and production”, 2nd edition, Pen Well Corp., Tulsa, Okla., USA).
[0003] To meet the rising global demand on energy, there is a need to further increase production of crude oil from oil reservoirs. An additional supplemental technique used for enhancing oil recovery from oil reservoirs is known as Microbial Enhanced Oil Recovery (MEOR) as described in U.S. Pat. No. 7,484,560. MEOR, which has the potential to be a cost-effective method for enhanced oil recovery, involves either stimulating the indigenous oil reservoir microorganisms or injecting specifically selected microorganisms into the oil reservoir to produce metabolic effects that lead to improved oil recovery.
[0004] The production of oil and gas from subterranean oil reservoirs requires installing various equipment and pipelines on the surface or the subterranean sites of the oil reservoir which come in contact with corrosive fluids in gas- and oil-field applications. Thus, oil recovery is facilitated by preserving the integrity of the equipment needed to provide water for water injection wells and to convey oil and water from the production wells. As a result, corrosion can be a significant problem in the petroleum industry because of the cost and downtime associated with replacement of corroded equipment.
[0005] Sulfate reducing bacteria (SRB) microorganisms, which produce hydrogen sulfide (H 2 S), are amongst the major contributors to corrosion of ferrous metal surfaces and oil recovery equipment. These microorganisms can cause souring, corrosion and, plugging and thus can have negative impact on a MEOR or a bioremediation process. Bioremediation refers to processes that use microorganisms to cleanup oil spills or other contaminants from either the surface or the subterranean sites of soil.
[0006] To combat corrosion, corrosion inhibitors—which are chemicals or agents that decrease the corrosion rate of a metal or an alloy and are often toxic to microorganisms—are used to preserve the water injection and oil recovery equipment in such wells. In the practice of the present invention a water injection well is a well through which water is pumped down into an oil producing reservoir for pressure maintenance, water flooding, or enhanced oil recovery. The significant classes of corrosion inhibitors include compounds such as: inorganic and organic corrosion inhibitors. For example, organic phosphonates, organic nitrogen compounds, organic acids and their salts and esters (Chang, R. J. et al., Corrosion Inhibitors, 2006, Specialty Chemicals, SRI Consulting).
[0007] US2006/0013798 describes using bis-quaternary ammonium salts as corrosion inhibitors to preserve metal surfaces in contact with the fluids to extend the life of these capital assets.
[0008] U.S. Pat. No. 6,984,610 describes methods to clean up oil sludge and drilling mud residues from well cuttings, surface oil well drilling and production equipment through application of acids, pressure fracturing and acid-based microemulation for enhanced oil recovery.
[0009] WO2008/070990 describes preconditioning of oil wells using preconditioning agents such as methyl ethyl ketone, methyl propyl ketone and methyl tertiary-butyl ether in the injection water to improve oil recovery. Mechanisms such as modifying the viscosity of the oil in the reservoir and enlivening the heavy oil were attributed to this method.
[0010] US2009/0071653 describes using surfactants, caustic agents, anti-caking agents and abrasive agents to prevent or remove the build-up of fluid films on the processing equipment to increase the well's capacity.
[0011] Studies indicate that long-term addition of chemicals or agents used to control undesirable events such as corrosion, scale, microbial activities, and foam formation in the water supply of a water injection well does not lead to their accumulation in high enough concentrations to adversely affect the microorganisms used in MEOR (Carolet, J-L. in: Ollivier and Magot ed., “Petroleum Microbiology”, chapter 8, pages 164-165, 2005, ASM press, Washington, D.C.).
[0012] However, viability of microorganisms used in MEOR or bioremediation processes is a concern. It can be desirable to modify MEOR or bioremediation treatments such that the viability of microorganisms used during MEOR is maintained throughout the oil recovery process such that MEOR or bioremediation processes become more effective.
SUMMARY OF THE INVENTION
[0013] The present disclosure relates to a method for improving the effectiveness of a MEOR or bioremediation process by detoxifying subterranean sites adjacent to oil wells, wherein the wells have been previously treated with corrosion inhibitors prior to inoculation of the microorganisms required for MEOR or bioremediation.
[0014] In one aspect the present invention is an oil recovery method comprising the steps of:
a) treating a subterranean site in a zone adjacent to a water injection well with a detoxifying agent wherein, prior to the treatment, corrosion inhibitors and their degradation products have been adsorbed into the zone and have accumulated to concentrations that are toxic to microorganisms used in microbial enhanced oil recovery and/or bioremediation processes, and thereby have formed a toxic zone, and b) adding an inoculum of microorganisms wherein the microorganisms comprise one or more species of: Comamonas, Fusibacter, Marinobacterium, Petrotoga, Shewanella, Pseudomonas, Vibrio, Petrotoga, Thauera , and Microbulbifer useful in microbial enhanced oil recovery to the water injection well;
wherein the corrosion inhibitor comprises an organic compound selected from the group consisting of organic phosphonates, organic nitrogen compounds such as amines, organic acids and their salts and esters, carboxylic acids and their salts and esters, sulfonic acids and their salts.
BRIEF DESCRIPTION OF THE FIGURES
[0017] FIG. 1 is the schematic representation of a water injection well and the subterranean sites adjacent to the water injection well. ( 1 ) is the flow of injection water into the well casing ( 7 ), ( 2 and 3 ) are rock layers, ( 4 ) is the perforations in the casing, ( 5 ) is the well bore, ( 6 ) is the face of the rock layer made by the well bore, ( 7 ) is the well casing, ( 8 ) is one side of the watered zone that is axis-symmetric with the injection well, shown by a dotted box in the rock layer ( 3 ).
[0018] FIG. 2 is the schematic of a model system used to simulate formation of a toxic zone. ( 9 ) is a long slim tube; ( 10 ) is a pressure vessel to constrain the slim tube; ( 11 and 12 ) are the opposite ends of the pressurized vessel; ( 13 ) is a pump; ( 14 ) is the feed reservoir; ( 15 ) is the water inlet for the pressure vessel; ( 16 ) is the back pressure regulator; ( 17 ) is the high pressure air supply; ( 18 ) is an inlet fitting connecting the slim tube inside the pressure vessel to the pump and pressure transducers; ( 21 ) is an outlet fitting connecting the slim tube inside the pressure vessel to the back pressure regulator and the low side of the differential pressure transducer; ( 19 ) is a differential pressure transducer; and ( 20 ) is an absolute pressure transducer.
[0019] FIG. 3 depicts titration of amine coated core sand; ♦ represent amine coated sand and □ represent first derivative of the titration curve (central differences).
[0020] FIG. 4 depicts titration of brine and core sand with 1N HCl; ▪ represent brine #1 with 10 grams of core sand; diamonds ♦ represent brine #1 only; represents the slope of brine #1 with 10 grams of core sand; and Δ represents the slope of brine #1 only.
[0021] FIG. 5 depicts titration of brine and core sand with 10% nitric acid; ♦ represent the concentration of amine observed in solution for a given pH.
[0022] FIG. 6 depicts titration of brine and core sand with 10% acetic acid; ♦ represent the concentration of amine observed in solution for a given pH.
DETAILED DESCRIPTION OF THE INVENTION
[0023] In one aspect, the present invention is a method for detoxifying the corrosion inhibitors and their degradation products in a subterranean site adjacent to a water injection well of an oil well site. Applicants have found that oil recovery processing aids—such as corrosion inhibitors, for example—can accumulate in the area adjacent to the water injection well and build to concentrations that are toxic to microorganisms used in MEOR or bioremediation. As the term is used herein, “detoxifying” or “detoxification of” a water injection site means removing or reducing the toxicity caused by corrosion inhibitors and their degradation products to microorganisms to allow their growth and activity of said microorganisms, used in MEOR or bioremediation.
[0024] For the purposes of the present invention, the term “toxic zone” refers to a subterranean site adjacent to the water injection well comprising toxic concentrations of agents such as corrosion inhibitors or their degraded products which have adverse effects on growth and metabolic activities of microorganisms used in MEOR and/or bioremediation. A toxic agent, as the term is used herein, is any chemical or biological agent that adversely affects growth and metabolic functions of microorganisms used in MEOR and/or bioremediation.
[0025] FIG. 1 is a schematic of a subterranean site adjacent to a water injection well. The injection water ( 1 ) flows into the well casing ( 7 ) which is inside the well bore ( 5 ) drilled through rock layers ( 2 and 3 ). A gap exists between the well casing ( 7 ) and the face ( 6 ) of the rock layer made by the well bore ( 5 ). Rock layer ( 2 ) represents impermeable rock above and below a permeable rock ( 3 ) that holds or traps the oil. The injection water ( 1 ) flows down the well casing ( 7 ) and passes through perforations in the casing ( 5 ) and into fractures ( 4 ) in the permeable rock ( 3 ). This injection water then flows through the permeable rock layer ( 3 ) and displaces oil from a watered zone ( 8 ) adjacent to the well bore. This zone extends radially out from the well bore ( 5 ) in all directions in the permeable rock layer ( 3 ). While the volume of permeable rock ( 3 ) encompassed by the dash line ( 8 ) is illustrated only on one side of the well bore it actually exists on all sides of the well bore. This watered zone represents the subterranean site adjacent to the water injection well.
[0026] Corrosion inhibitors that can accumulate to levels that are toxic to microorganisms used in MEOR are, for example: inorganic corrosion inhibitors such as chlorine, hypochlorite, bromine, hypobromide and chlorine dioxide. Those used to combat corrosion caused by SRB microorganisms include, but are not limited to: nitrates (e.g., calcium or sodium salts), nitrite, molybdate, (or a combination of nitrate, nitrite and molybdate), anthraquinone, phosphates, salts containing chrome and zinc and other inorganics, including hydrazine and sodium sulfite (Sanders and Sturman, chapter 9, page 191, in: “Petroleum microbiology” page 191, supra and Schwermer, C. U., et al., Appl. Environ. Microbiol., 74: 2841-2851, 2008).
[0027] Organic compounds used as corrosion inhibitors include: acetylenic alcohols, organic azoles, gluteraldehyde, tetrahydroxymethyl phophonium sulfate (THPS), bisthiocyanate acrolein, dodecylguanine hydrochloride, formaldehyde, chlorophenols, organic oxygen scavengers and various nonionic surfactants.
[0028] Other organic corrosion inhibitors include, but are not limited to: organic phosphonates, organic nitrogen compounds including primary, secondary, tertiary or quaternary ammonium compounds (hereinafter referred to generically as “amines”), organic acids and their salts and esters, carboxylic acids and their salts and esters, sulfonic acids and their salts.
[0029] Applicants have determined that corrosion inhibitors can accumulate by adsorption into or on the subterranean site (e.g., sand stone, unconsolidated sand or limestone) or into the oil that has been trapped in the oil reservoir subterranean site. Long-term addition of these chemicals results in their accumulation and formation of a toxic zone in subterranean sites adjacent to the water well with adverse effects on microbial inocula intended for MEOR and/or bioremediation applications.
[0030] A model system to simulate formation of a toxic zone can be used to study its effects on the survival of microorganisms. For example, a model system called a slim tube can be set up and packed with core sand from an oil well site. The model system as described herein can be set up using tubing, valves and fittings compatible with the crude oil or the hydraulic solution used that can withstand the range of applied pressure during the process. An absolute pressure transducer, differential pressure transducer and back pressure regulator for Example made by (Cole Plamer, Vernon hill, IL and Serta, Boxborough, Mass) are required and are commercially available to those skilled in the art.
[0031] The model toxic zone can be established using solutions of amines and/or amine mixtures and flushing them through a tube packed with core sand from an oil reservoir. Other corrosion inhibitors suitable for use in constructing a model can comprise organic phosphonates or anthraquinone or phosphates. The concentration of the corrosion inhibitors used to create the model toxic zone may be from 0.01 to 100 parts per million.
[0032] Detoxification of the toxic zone involves degradation, desorption or dispersion of the accumulated toxic chemicals or agents using detoxifying agents. The term “detoxifying agent” therefore refers to any chemical that either disperses or destroys the toxic chemicals and agents described herein and renders them non-toxic to microorganisms.
[0033] Detoxification of the chemicals accumulated in the toxic zone may be achieved using a degradation agent. A degradation agent, as the term is used herein, is an agent that destroys or assists in the destruction of toxic agents found in the toxic zone. Degradation agents can include, for example, strong oxidizers that chemically react with corrosion inhibitors when added to the injection water and degrade them into less toxic or non-toxic products. Degradation agents include strong oxidizing agents such as, for example, nitrates, nitrites, chlorates, percholorates and chlorites.
[0034] Detoxification of the chemicals accumulated at the toxic zone may also be achieved using a dispersing agent. A “dispersing agent” as the term is used herein includes any chemical that lowers the pH of the solution, ionizes the amines and solubilizes them into the water during water flooding and allows for natural dispersion and diffusion to lower the concentration where it is no longer toxic to MEOR or bioremediation microorganisms. For example, amines are fairly non-reactive under mild conditions, however, they become ionized at lower pH. Thus treatment of the amines with an acid increases their solubility and releases them from oil and/or from rocks and disperses them from the toxic zone. The solubilized amines may therefore enter into the water flowing through the well. A combination of radial flow, dispersion and desorption may allow the solubilized amines to be diluted and dispersed over a large area (from at least 10 to about 200 feet (from at least 3 meters to about 7 meters)) of the oil well. Following dilution and dispersion of the amines over a much larger area, their concentrations within the subterranean site of the well would have been consequently reduced to non-toxic levels for MEOR or bioremediation microorganisms. However, even if the amines concentrations were still at toxic levels, the toxic zone in the subterranean site adjacent to the injector well will have become non-toxic to microorganisms. Thus, the microbial inoculum may pass through the subterranean site adjacent to the water injection well without encountering toxic levels of the amines.
[0035] In another embodiment, hydrogen peroxide may be added to the toxic zone, as both a degradation and a dispersing agent, from about 1,000 parts per million to 70,000 parts per million by volume of water. In another embodiment, perchlorates may be added, as both a degradation and a dispersing agent, from about 1 parts per million to about 10,000 parts per million.
[0036] In another embodiment, any acid capable of lowering the pH at least 1 unit less than the equivalence point of the amine (as measured in the Examples below) may be used. The acid used to ionize the amines may include, but is not limited to, nitric acid, acetic acid, oxalic acid, hydrofluoric acid, and hydrochloric acid. Acid may be added from about 0.1 weight % to about 20 weight % to the water that is being pumped into the toxic zone.
[0037] In a MEOR process, viable microorganisms are added to the water being injected into the water injection well. The term “inoculum of microorganisms” refers to the concentration of viable microorganisms added. These microorganisms colonize, that is to grow and propagate, at the subterranean sites adjacent to the water injection well to perform their MEOR.
[0038] Microorganisms useful for this application may comprise classes of facultative aerobes, obligate anaerobes and denitrifiers. The inoculum may comprise of only one particular species or may comprise two or more species of the same genera or a combination of different genera of microorganisms.
[0039] The inoculum may be produced under aerobic or anaerobic conditions depending on the particular microorganism(s) used. Techniques and various suitable growth media for growth and maintenance of aerobic and anaerobic cultures are well known in the art and have been described in “Manual of Industrial Microbiology and Biotechnology” (A. L. Demain and N. A. Solomon, ASM Press, Washington, D.C., 1986) and “Isolation of Biotechnological Organisms from Nature”, (Labeda, D. P. ed. p 117-140, McGraw-Hill Publishers, 1990).
[0040] Examples of microorganisms useful in MEOR in this application include, but are not limited to: Comamonas terrigena, Fusibacter paucivorans, Marinobacterium georgiense, Petrotoga miotherma, Shewanella putrefaciens, Pseudomonas stutzeri, Vibrio alginolyticus, Thauera aromatica, Thauera chlorobenzoica and Microbulbifer hydrolyticus.
[0041] In one embodiment an inoculum of Shewanella putrefaciens (ATCC PTA-8822) may be used to inoculate the slim tube test. In another embodiment Pseudomonas stutzeri (ATCC PTA8823) may be used to inoculate the slim tube. In another embodiment Thauera aromatica (ATCC9497) may be used to inoculate the slim tube.
[0042] The inoculum of microorganisms useful for bioremediation may comprise, but are not limited to, various species of: Corynebacteria, Pseudomonas, Achromobacter, Acinetobacter, Arthrobacter, Bacillus, Nocardia, Vibrio , etc. Additional useful microorganisms for bioremediation are known and have been cited, for example, in Table 1 of U.S. Pat. No. 5,756,304, columns 30 and 31.
[0043] The inoculum for injecting into the water well injection site may comprise one or more of the microorganisms listed above.
EXAMPLES
[0044] The present invention is further defined in the following Examples. It should be understood that these Examples, while indicating preferred embodiments of the invention, are given by way of illustration only. From the above discussion and these Examples, one skilled in the art can ascertain the essential characteristics of this invention, and make various changes and modifications to the invention to adapt it to various uses and conditions.
General Methods
Chemicals and Materials
[0045] All reagents, and materials used for the growth and maintenance of microbial cells were obtained from Aldrich Chemicals (Milwaukee, Wis.), DIFCO Laboratories (Detroit, Mich.), GIBCO/BRL (Gaithersburg, Md.), or Sigma Chemical Company (St. Louis, Mo.), unless otherwise specified.
Amines Analysis
[0046] Concentration of amines, in media and water, were analyzed by gas chromatography (GC). An Agilent Model 5890 (Agilent, Wilmington, Del.), GC equipped with a flame photoionization detector and a split/splitless injector, a DB-FFAP column (30 meter length×0.32 millimeter (mm) depth×0.25 micrometer particle size). The equipment had an Agilent ALS Autoinjector, 6890 Model Series with a 10 milliliter (ml) syringe. The system was calibrated using a sample of N,N-Dimethyl-1-Dodecaneamine (Aldrich). Helium was used as the carrier gas. A temperature gradient of 50 degrees Celsius (° C.) to 250° C. at 30° C. increase per minute (min) was used. Retention times (in minutes, min) for various chemicals of interest included: N,N-Dimethyl-1-Dodecaneamine (8.08 min); N,N-Dimethyl-1-Tetradecaneamine (8.85 min); N,N-Dimethyl-1-Hexadecane-amine (9.90 min); N,N-Dimethyl-1-Octadecaneamine (10.26 min) and N-Methyl,N-Benzyl)-1-Tetradecaneamine (11.40 min).
Example 1
Establishing a Toxic Zone in Core Sand from an Oil Well Using a Mixture of Amines in a Model System
[0047] A sample of the sand obtained from the Schrader Bluff formation at the Milne Point Unit of the Alaska North Slope was cleaned by washing with a solvent made up of a 50/50 (volume/volume) mixture of methanol and toluene. The solvent was subsequently drained and then evaporated off the core sand to produce clean, dry, flow able core sand. This core sand was sieved to remove particles with less than one micrometer in size and was then packed tightly into a four foot (121.92 cm) long flexible slim tube ( 9 ) and compacted by vibration using a laboratory engraver. Both ends of the slim tubes were capped to keep the core sand in it. The complete apparatus is shown in FIG. 2 . Tubing that can sustain the amount of pressures used in the slim tube, was connected to the end caps. The slim tube ( 9 ) was mounted into the pressure vessel ( 10 ) with tubing passing through the ends ( 11 and 12 ) of the pressure vessel using pressure fittings ( 18 and 21 ). Additional fittings and tubing were used to connect the inlet of the slim tube ( 11 ) to a pressure pump ( 13 ) and a feed reservoir ( 14 ).
[0048] Additional fittings and tubing connected the inlet of the slim tube to an absolute pressure transducer ( 20 ) and the high pressure side of a differential pressure transducer ( 19 ). Fittings and tubing connected the outlet of the slim tube ( 12 ) to the low pressure side of a differential pressure transducer ( 19 ) and to a back pressure regulator ( 16 ). The signals from the differential pressure and the absolute pressure transducer were ported to a computer and the pressure readings were monitored and periodically recorded. The pressure vessel ( 10 ) around the slim tube was filled with water through a water port ( 15 ). This water was then slowly pressurized with air ( 17 ) to a pressure of about 105 per square inch (psi) (0.72 mega Pascal) while brine #1 from the feed reservoir ( 14 ) (Table 1) flowed through the slim tube and left the slim tube through the back pressure regulator ( 16 ). This operation was performed such that the pressure in the slim tube was always 5 to 20 psi (0.034-0.137 mega Pascal) below the pressure in the pressure vessel ( 10 ).
[0000]
TABLE 1
Ingredients of Brine #1
(no nutrient brine - gram per liter (gr/L) of tap water
NaHCO 3
1.38
grams (gr)
CaCl 2 *6H 2 O
0.39
gr
MgCl 2 *6H 2 O
0.220
gr
KCl
0.090
gr
NaCl
11.60
gr
NaHCO 3
1.38
gr
Trace metals
1
ml
Trace vitamins
1
ml
Na 3 (PO 4 )
0.017
gr (=10 parts per million (ppm) PO 4 )
NH4Cl
0.029
gr (=10 ppm NH 4 )
Acetate
0.2
gr (200 ppm acetate)
The pH of brine #1 was adjusted to 7.0 with either HCl or NaOH and the solution was filter sterilized.
[0000]
TABLE 2
Concentration of the amines added to Brine #1
Minor
other
NN-Dimethyl-1-
NN-Dimethyl-1-
NN-Dimethyl-
N-methylN-
amine
amine
Dodecaneamine
tetradecaneamine
Methanethioamide ??
Caprolactam
Benzyl-1-tetradecaneamine
Sample
PPM
PPM
PPM
PPM
PPM
PPM
PPM
Brine #1 w/
25
124
23
1
0
0
2
amine
[0049] Once the pressure inside and outside the slim tube was established, one pore volume of the crude oil from an oil reservoir of the Milne Point Unit of the Alaskan North Slope was pumped into the slim tube. This process was performed in several hours (h). Once the crude oil had saturated the core sand in the slim tube and was observed in the effluent, the flow was stopped and the oil was allowed to age in the core sand for 3 weeks. At the end of this time, brine #1 was pumped through the slim tube at a rate of ˜1.5-3.5 milliliter per hour (ml/h) (˜1 pore volume every 20 h). Samples were taken from the effluent and the concentration of natural microflora in them was determined.
[0050] After 51 pore volumes of flow through the slim tube the concentration of natural microflora in the system was about 1×10 7 colony forming units per milliliter (CFU/ml). At this point, a mixture of amines (hereafter amines/brine mixture) was added at 150 ppm concentration to brine #1. The approximate composition of the mixture of amines (Table 2) consisted of 7 different amine components that were identified. Five were identified by Mass Spectrometry (Agilent Technologies, Inc. Santa Clara, Calif.) as N-N-dimethyl-1-dodecaneamine, N-N-dimethyl-1-tetradecane-amine, N-N-dimethyl-methane-thioamide, caprolactam and N-methyl-N-benzyl-1-tetradecaneamine. Two of the components were identified as amines but specific chemical formulas could not be assigned to them because the Mass Spectral Fragmentation patterns could not be deciphered. These are labeled in Table 2 as “minor amine” and “other amine”. Analysis of the effluent from the slim tube did not indicate presence of any amines in it. The experiment was continued by pumping 150 ppm of the mixture of amines in brine #1 through the slim tube.
[0051] After 77 pore volumes of the mixture of brine #1 with 150 ppm of mixture of amines was pumped into the slim tube no amines were observed in the effluent.
[0052] After 80 pore volumes of the mixture of brine #1 with 150 ppm of mixture of amines was pumped into the slim tube a total of about 1 gr of the mixture of amines had flowed through the slim tube. At this point, 80 ppm of amines was finally observed in the effluent of the slim tube. This very long delay in seeing the amines in the effluent means that virtually all the amines had been trapped in the slim tube. In addition, at this time, no natural microflora could be seen in the effluent indicating that the slim tube had become toxic enough to kill all existing microflora. At this point, pumping the amines-free brine#1 was started in an attempt to flush the amines out of the slim tube and to make it less toxic.
[0053] After 24 pore volumes of the amines-free brine#1 had been pumped through the slim tube, 51 ppm of amines was detected in the effluent. The slim tube was then inoculated with one pore volume of Shewanella putrefaciens (ATCC PTA-8822) at a concentration of approximately 1×10 9 CFU/ml. This inoculation was not allowed to remain in the slim tube. Instead, amines-free brine#1 was flushed through the slim tube immediately after the inoculation. Consequently the microbes resided in the slim tube for only a few hours during the transit through it. Thus, it was anticipated that the microorganisms' concentration in the effluent could be measured in the effluent eluting the slim tube. However, remarkably no microorganisms (representing about a 9 log kill) were detected in the slim tube effluent despite the short residence time of the inoculum in the slim tube. This experiment confirmed that a toxic zone had been established in the slim tube. In a continued attempt to detoxify the slim tube, brine #1 alone was continuously pumped through it.
[0054] After 79 pore volumes of the amines-free brine #1 had been pumped through the slim tube, the amines concentration in the effluent of the slim tube was measured at 30 ppm. The slim tube was inoculated with another pore volume of Shewanella putrefaciens (at 1×10 9 CFU/ml). The CFU/ml in an effluent sample was about 1×10 4 showing more than a 5 log kill of this microorganism had occurred immediately following inoculation. This experiment underlined the continued toxic effect of the amines despite extended washing of the tube with the amines-free brine#1 solution.
[0055] After 108 pore volumes of the amines-free brine #1 had been pumped through the slim tube, the amine concentration in the effluent was measured at 5 ppm. The slim tube was inoculated with an additional one pore volume of Shewanella putrefaciens containing 1×10 9 CFU/ml. The CFU/ml in the effluent sample of the slim tube immediately following inoculation indicated a 4-5 log kill of this microorganism despite the extended washing with the amines-free brine#1 and the decrease in the amines concentration in the effluent. These results further confirmed the continued toxic effect of the mixture of amines accumulated in the slim tube.
[0056] After 143 pore volumes of the amines-free brine #1 had been pumped through the slim tube one pore volume of an inexpensive odorless mineral spirits (OMS)(Parks OMS, Zinsser Co., Inc., Somerset Jew Jersey #2035 CAS #8052-41-3) was pumped through the slim tube in an attempt to remove the remaining mixture of amines. After this flush of OMS, pumping of amines-free brine #1 through the slim tube was continued.
[0057] After 149 pore volumes of amines-free brine #1 had been pumped through the slim tube, the amines concentration in the effluent was measured at 4 ppm and the slim tube was inoculated with an additional one pore volume of Shewanella putrefaciens (1×10 9 CFU/ml). A count of microorganisms in the sample of the slim tube's effluent showed a 2-3 log kill (99 to 99.9%) despite the OMS flush and the extended washing with the amines-free brine#1. These results confirmed that the toxic zone in the slim tube was still killing virtually all the microorganisms added to the tube.
[0058] After 168 pore volumes of the amines-free brine #1 had been pumped through the slim tube, one pore volume of a solution of 10% HCl in water was pumped through the slim tube to remove the amines. After this acid wash, the amines-free brine #1 was continuously pumped through the slim tube.
[0059] Following the acid wash treatment, an additional 2 pore volumes of the amines-free brine #1 was pumped through the slim tube and the amines concentration in the effluent was measured at 0.5 ppm. The slim tube was then inoculated with an additional one pore volume of Shewanella putrefaciens (1×10 9 CFU/ml). The CFU/ml in the effluent showed about a 0.4 log kill of this microorganism. These results underlined survival of more microorganisms following the acid wash of the slim tube and the effectiveness of using an acid to detoxify the toxic zone in the slim tube. Table 3 below summarizes results of the various tests described above.
[0000]
TABLE 3
Summary of the amount of amine observed in the slim tube's effluent and
the fraction of the microorganisms killed (log kill) during residence in the
slim tube.
Total Pore
volume of fluid
ppm
pumped
amines
log kill
through slim
in the
after
tube
effluent
inoculating
51
0
0
131
80.5
nd
amines flood
stopped
155
51.1
9.6
210
29.5
5.3
(at least)
239
4.7
4.5
(at least)
274
OMS flooded
~1 pore volume
280
4.2
2.4
299
10% HCL flooded
for 1 PV
301
0.5
0.4
PV = pore volume;
nd = not detected
Example 2
Removal of N N-Dimethyl-1-Dodecanamine from Core Sand Through their Ionization at Low pH Using Hydrochloric Acid
[0060] 38 milligrams (mg) of N N-Dimethyl-1-Dodecanamine (hereafter referred to as “the amine”) was added to 10.210 gr of Pentane. This solution was added to 10.1845 gr of specific sand layers (Oa and Ob) obtained from the Schrader Bluff formation of the Milne Point Unit of the Alaskan North slope. The oil content of the sand was first removed using a mixture of methanol and toluene (50/50, volume/volume) as solvent washes. The solvent mixture was subsequently evaporated off the core sand to produce clean, dry, flowable core sand. This sand was mixed with the amine and pentane solution to produce a slurry. This slurry was thoroughly mixed and the pentane was evaporated off leaving the amine on the sand (hereafter referred to as sand/amine mixture). 100 ml of brine #2 (Table 3) was added to the sand/amine mixture to create the sand/amine/brine mixture. The initial pH of the sand/amine/brine mixture was 8.4. The concentration of the amine in the water should have been 380 ppm if all the amine were dissolved in brine #2. Analysis of a sample of sand/amine/brine mixture by GC did not reveal the presence of any amines in the test sample (i.e., the amine conc. was ˜<1 ppm). The fact that the amine was not detected underlined its strong binding to the sand particles. 0.1 ml of 1 normal (N) HCl was added to this solution, and the pH and the amine concentration was measured again. This step was repeated several times and the analyses results are shown in both Table 4 and in FIG. 3 . Complete ionization and solubilization of the amine in the water was observed at pH below ˜6.0. This is a surprising finding since the pKa of HCl is −6.2 (Langes Handbook of Chemistry, 14 th edition, page 8.14, 1992, McGraw-Hill, Inc., New York). Therefore, the concentration of the HCl required for this step to completely ionize the amine and removed it from the toxic core sand may be further reduced several orders of magnitude from the 10% concentration used in this example. The data underlines the remarkable efficiency of an acid at ionizing and removing the amine from the sand.
[0000]
TABLE 3
Composition of brine #2 (gr/L of deionized water)
NaHCO 3
1.38 gr
CaCl 2 *6H 2 O
0.39 gr
MgCl 2 *6H 2 O
0.220 gr
KCl
0.090 gr
NaCl
11.60 gr
[0000]
TABLE 4
Amine concentration measured in Example 2
N-N-
First
dimethyl-1-
derivative
dodeanamine
(change in
(ppm) in slim
amine/change
1N HCl
sample
tube effluent
in pH)
pH
(ml)
Amine titrate st
0.00
8.14
0.00
Amine titrate 1
46.41
63.75
7.37
0.10
Amine titrate 2
59.29
63.42
7.21
0.10
Amine titrate 3
67.97
24.34
7.03
0.10
Amine titrate 4
74.38
160.35
6.59
0.10
Amine titrate 5
212.28
412.18
6.13
0.10
Amine titrate 6
288.72
679.86
6.07
0.10
Amine titrate 7
273.47
−148.78
6.04
0.05
Amine titrate 8
275.33
119.35
5.98
0.05
Amine titrate 9
303.31
65.90
5.79
0.05
Amine titrate 10
314.21
15.17
5.39
0.05
Amine titrate 11
328.48
3.24
4.13
0.05
Amine titrate 12
321.33
11.80
3.19
0.05
Amine titrate 13
342.88
47.42
2.91
0.05
Amine titrate 14
342.67
−6.52
2.74
0.05
Amine titrate 15
340.92
79.86
2.61
0.05
Amine titrate 16
369.02
80.22
2.41
0.10
Amine titrate 17
368.19
2.25
2.27
0.10
Amine titrate 18
369.54
7.51
2.18
0.10
Amine titrate 19
369.47
0.12
2.10
0.10
Amine titrate 20
369.56
2.04
0.10
Example 3
Capacity of Core Sand to Neutralize Acid
A. Titration of Brine #2 in the Absence of Core Sand
[0061] The intent of this experiment was to determine the capacity of the core sand described in Example 2 to neutralize the HCl intended to ionize the amine accumulated in the sand.
[0062] To set up a control test, 100 ml of brine #2 was titrated with 1 N HCl to initial pH of 8.1. An aliquot (0.1 ml) of 1N HCl was added to the brine #2 and the pH was measured. The HCl addition was repeated several times and the pH was measured after each addition. Results of these analyses are shown in both Table 5 and in FIG. 4 . The data indicated that about 2.25 milliequivalents of HCl were needed to achieve the equivalence point of about pH 4 corresponding to about 100% recovery of the carbonate present in brine #2.
[0000] TABLE 5 Titration of synthetic injection brine #2 in the absence of the amine First derivative of 1N HCl sample pH pH (ml) Addition 1 8.10 0.00 Addition 2 7.67 0.73 0.10 Addition 3 7.37 0.49 0.10 Addition 4 7.18 0.35 0.10 Addition 5 7.02 0.29 0.10 Addition 6 6.89 0.23 0.10 Addition 7 6.79 0.21 0.10 Addition 8 6.68 0.19 0.10 Addition 9 6.60 0.17 0.10 Addition 10 6.51 0.15 0.10 Addition 11 6.45 0.15 0.10 Addition 12 6.36 0.18 0.10 Addition 13 6.27 0.18 0.10 Addition 14 6.18 0.18 0.10 Addition 15 6.09 0.17 0.10 Addition 16 6.01 0.17 0.10 Addition 17 5.92 0.18 0.10 Addition 18 5.83 0.19 0.10 Addition 19 5.73 0.33 0.10 Addition 20 5.50 0.32 0.10 Addition 21 5.41 0.33 0.10 Addition 22 5.17 0.74 0.10 Addition 23 4.67 1.94 0.10 Addition 24 3.23 1.86 0.10 Addition 25 2.81 0.62 0.10 Addition 26 2.61 0.36 0.10 Addition 27 2.45 0.25 0.10 Addition 28 2.36 0.17 0.10 Addition 29 2.28 0.10
B. Titration of Brine #2 with Core Sand
[0063] 100 ml of brine #2 plus 10 gr of the same core sand (brine/sand mixture) used in Example 2, was titrated with 1N HCl. The initial pH of the brine/sand mixture was 7.88. 0.1 ml aliquots of 1N HCl were added to this mixture repeatedly, and the pH was measured after each HCl addition. The results shown in both Table 6 and in FIG. 4 indicated that addition of 0.3 milliequivalents of HCl was needed to achieve the equivalence point with 10 gr of sand present. The data obtained in this experiment underlines the slight capacity of the core sand to neutralize the added HCl. Consequently a small concentration of an acid, such as HCl, ionized the amine associated with the core sand without getting neutralized by reaction with the sand.
[0000]
TABLE 6
Titration of brine #2 and 10 gr of core sand
Brine contained
1.87 gr NaHCO 3
2.60 ml of 1N
Used 10.103 gr of core sand
Sample
HCL at pH
Slope of pH (first derivative)
ml 1N HCl
1
7.88
0.00
2
7.55
0.53
0.10
3
7.35
0.36
0.10
4
7.19
0.30
0.10
5
7.05
0.24
0.10
6
6.95
0.20
0.10
7
6.85
0.18
0.10
8
6.77
0.18
0.10
9
6.67
0.17
0.10
10
6.60
0.14
0.10
11
6.53
0.14
0.10
12
6.46
0.13
0.10
13
6.40
0.12
0.10
14
6.34
0.13
0.10
15
6.27
0.13
0.10
16
6.21
0.13
0.10
17
6.14
0.15
0.10
18
6.06
0.16
0.10
19
5.98
0.16
0.10
20
5.90
0.17
0.10
21
5.81
0.21
0.10
22
5.69
0.29
0.10
23
5.52
0.34
0.10
24
5.35
0.45
0.10
25
5.07
0.80
0.10
26
4.55
1.14
0.10
27
3.93
1.13
0.10
28
3.42
0.86
0.10
29
3.07
0.52
0.10
30
2.90
0.33
0.10
31
2.74
0.24
0.10
32
2.66
0.29
0.10
33
2.45
0.34
0.20
34
2.32
0.23
0.20
35
2.22
0.18
0.20
36
2.14
0.20
Example 4
Removal of N—N-Dimethyl-1-Dodecanamine from Core Sand Through their Ionization at Low pH Using 10% Nitric Acid
[0064] The procedure outlined in Example 2 was used to produce the sand/amine mixture except that 519 mg of the amine, 10 gr of Pentane. and 60.062 gr of sand from the Oa and Ob layers were used. 29.065 gr of this sand/amine mixture was added to 100 ml of brine #2 (Table 3) to create the sand/amine/brine mixture. The initial pH of the sand/amine/brine mixture was 8.28. The concentration of the amine in the water should have been about 2000 ppm if all the amine was dissolved in brine #2. Instead, analysis of a sample of brine #2 in contact with the sand/amine/brine mixture as described above showed that the amine concentration was ˜85 ppm, i.e., far less than what was expected. The fact that only a small amount of the amine was detected in brine #2 underlined the strong binding of the amine to the sand particles. 0.1 ml of 10 weight percent (wt %) nitric acid in water was added to this solution, and the pH and the amine concentration were measured again. This step was repeated several times and the analyses results are shown in both Table 7 and in FIG. 5 . Complete ionization and solubilization in the water of the amine was observed at a pH below ˜6.7. This is a surprising finding since the pKa of nitric acid is −1.37 (Langes Handbook of Chemistry, 14 th edition, page 8.15, 1992, McGraw-Hill, Inc., New York), the concentration of the nitric acid required for this step may be further reduced several orders of magnitude from the 10 wt % used in this experiment without any negative impact on removal of the amines from the core sand.
[0000]
TABLE 7
Amine concentration measured in Example 4
ppm N-N-
dimethyl-1-
sample
dodeanamine
pH
ml 10% HNO 3
start
85
8.28
0
1
110
8.13
0.1
2
211
7.72
0.1
3
216
7.42
0.1
4
235
7.25
0.1
5
540
7.2
0.1
6
745
7.29
0.1
7
1153
7.33
0.1
8
1210
7.29
0.1
9
1327
7.18
0.1
10
1315
7.11
0.1
11
1413
6.99
0.1
12
1667
6.85
0.1
13
1897
6.73
0.1
14
1853
6.64
0.1
15
1858
6.59
0.1
16
1788
6.28
0.2
17
1822
5.8
0.2
18
1975
3.46
0.2
Example 5
Removal of N—N-Dimethyl-1-Dodecanamine from Core Sand Through its Ionization at Low pH Using 10% Acetic Acid
[0065] The same procedure outlined in Example 4 was repeated here to produce the sand/amine mixture. 30.85 grams (gr) of the sand/amine mixture was added to 100 ml of brine #2 (Table 3) to create the sand/amine/brine mixture. The initial pH of the sand/amine/brine mixture was 8.52. The concentration of the amine in the water should have been about 2000 ppm if all the amine were dissolved in brine #2. Instead, analysis of brine #2 in contact with the sand/amine/brine mixture, as described above, showed that the amine concentration was ˜67 ppm, i.e., far less than what was expected. The fact that only a small amount of the amine was detected in the brine #2 underlined the strong binding of the amine to the sand particles. 0.1 ml of 10 wt % acetic acid was added to this solution, and the pH and the amine concentration were measured again. This step was repeated several times and the analyses results are shown in both Table 8 and in FIG. 6 . Complete ionization and solubilization in the water of the amine was observed at pH below ˜6.7. This is a surprising finding since the pKa of acetic acid is 4.756 (Langes Handbook of Chemistry, 14 th edition, page 8.19, 1992, McGraw-Hill, Inc., New York). Consequently, the concentration of the acetic acid required for this step may be further reduced significantly from what was used in this example without any negative impact on removal of the amine from the core sand.
[0066] The observations described above illustrate that a weak organic acid, like acetic acid can be as effective as a strong inorganic acid, like hydrochloric acid, at ionizing and separating the amines from the toxic core sand. It can therefore be concluded that to remove the toxic zone from a subterranean site, any acid that decreases the pH of a solution below about 6.7 can be used.
[0000]
TABLE 8
Amine concentration measured in Example
ppm N-N-
dimethyl-1-
sample
dodeanamine
pH
ml 10% acetic acid
start
67
8.52
0
1
63
8.01
0.1
2
107
7.41
0.1
3
215
7.4
0.1
4
497
7.37
0.1
5
512
7.23
0.1
6
969
7.12
0.1
7
1239
6.98
0.1
8
1453
6.89
0.1
9
1583
6.75
0.1
10
1579
6.56
0.1
11
1616
6.39
0.1
12
1759
6.4
0.1
13
1736
6.02
0.2
14
1718
5.4
0.2
15
1743
5.04
0.2
16
1931
4.86
0.2
17
1995
4.73
0.2
18
1913
4.61
0.2
19
1881
4.52
0.2
20
1837
4.43
0.2
21
1885
4.36
0.3 | A method to improve the effectiveness of MEOR or bioremediation processes has been disclosed. In this method toxic chemicals accumulated in subterranean sites adjacent to the water injection wells are either dispersed or removed prior to introduction of microbial inocula for enhanced microbial oil recovery or bioremediation of these sites. | Summarize the patent information, clearly outlining the technical challenges and proposed solutions. | [
"FIELD OF THE INVENTION [0001] The invention relates to the field of microbial enhanced oil recovery and bioremediation of subterranean contaminated sites.",
"Specifically, it relates to methods of treating the toxic chemicals accumulated in subterranean sites adjacent to the water injection wells prior to introduction of microbial inocula for microbial enhanced oil recovery or bioremediation of these sites.",
"BACKGROUND OF THE INVENTION [0002] Traditional oil recovery techniques which utilize only the natural forces present at an oil well site, allow recovery of only a minor portion of the crude oil present in an oil reservoir.",
"Oil well site generally refers to any location where wells have been drilled into a subterranean rock containing oil with the intent to produce oil from that subterranean rock.",
"An oil reservoir typically refers a deposit of subterranean oil.",
"Supplemental recovery methods such as water flooding have been used to force oil through the subterranean location toward the production well and thus improve recovery of the crude oil (Hyne, N.J., 2001, “Non-technical guide to petroleum geology, exploration, drilling, and production”, 2nd edition, Pen Well Corp.",
", Tulsa, Okla.",
", USA).",
"[0003] To meet the rising global demand on energy, there is a need to further increase production of crude oil from oil reservoirs.",
"An additional supplemental technique used for enhancing oil recovery from oil reservoirs is known as Microbial Enhanced Oil Recovery (MEOR) as described in U.S. Pat. No. 7,484,560.",
"MEOR, which has the potential to be a cost-effective method for enhanced oil recovery, involves either stimulating the indigenous oil reservoir microorganisms or injecting specifically selected microorganisms into the oil reservoir to produce metabolic effects that lead to improved oil recovery.",
"[0004] The production of oil and gas from subterranean oil reservoirs requires installing various equipment and pipelines on the surface or the subterranean sites of the oil reservoir which come in contact with corrosive fluids in gas- and oil-field applications.",
"Thus, oil recovery is facilitated by preserving the integrity of the equipment needed to provide water for water injection wells and to convey oil and water from the production wells.",
"As a result, corrosion can be a significant problem in the petroleum industry because of the cost and downtime associated with replacement of corroded equipment.",
"[0005] Sulfate reducing bacteria (SRB) microorganisms, which produce hydrogen sulfide (H 2 S), are amongst the major contributors to corrosion of ferrous metal surfaces and oil recovery equipment.",
"These microorganisms can cause souring, corrosion and, plugging and thus can have negative impact on a MEOR or a bioremediation process.",
"Bioremediation refers to processes that use microorganisms to cleanup oil spills or other contaminants from either the surface or the subterranean sites of soil.",
"[0006] To combat corrosion, corrosion inhibitors—which are chemicals or agents that decrease the corrosion rate of a metal or an alloy and are often toxic to microorganisms—are used to preserve the water injection and oil recovery equipment in such wells.",
"In the practice of the present invention a water injection well is a well through which water is pumped down into an oil producing reservoir for pressure maintenance, water flooding, or enhanced oil recovery.",
"The significant classes of corrosion inhibitors include compounds such as: inorganic and organic corrosion inhibitors.",
"For example, organic phosphonates, organic nitrogen compounds, organic acids and their salts and esters (Chang, R. J. et al.",
", Corrosion Inhibitors, 2006, Specialty Chemicals, SRI Consulting).",
"[0007] US2006/0013798 describes using bis-quaternary ammonium salts as corrosion inhibitors to preserve metal surfaces in contact with the fluids to extend the life of these capital assets.",
"[0008] U.S. Pat. No. 6,984,610 describes methods to clean up oil sludge and drilling mud residues from well cuttings, surface oil well drilling and production equipment through application of acids, pressure fracturing and acid-based microemulation for enhanced oil recovery.",
"[0009] WO2008/070990 describes preconditioning of oil wells using preconditioning agents such as methyl ethyl ketone, methyl propyl ketone and methyl tertiary-butyl ether in the injection water to improve oil recovery.",
"Mechanisms such as modifying the viscosity of the oil in the reservoir and enlivening the heavy oil were attributed to this method.",
"[0010] US2009/0071653 describes using surfactants, caustic agents, anti-caking agents and abrasive agents to prevent or remove the build-up of fluid films on the processing equipment to increase the well's capacity.",
"[0011] Studies indicate that long-term addition of chemicals or agents used to control undesirable events such as corrosion, scale, microbial activities, and foam formation in the water supply of a water injection well does not lead to their accumulation in high enough concentrations to adversely affect the microorganisms used in MEOR (Carolet, J-L.",
"in: Ollivier and Magot ed.",
", “Petroleum Microbiology”, chapter 8, pages 164-165, 2005, ASM press, Washington, D.C.).",
"[0012] However, viability of microorganisms used in MEOR or bioremediation processes is a concern.",
"It can be desirable to modify MEOR or bioremediation treatments such that the viability of microorganisms used during MEOR is maintained throughout the oil recovery process such that MEOR or bioremediation processes become more effective.",
"SUMMARY OF THE INVENTION [0013] The present disclosure relates to a method for improving the effectiveness of a MEOR or bioremediation process by detoxifying subterranean sites adjacent to oil wells, wherein the wells have been previously treated with corrosion inhibitors prior to inoculation of the microorganisms required for MEOR or bioremediation.",
"[0014] In one aspect the present invention is an oil recovery method comprising the steps of: a) treating a subterranean site in a zone adjacent to a water injection well with a detoxifying agent wherein, prior to the treatment, corrosion inhibitors and their degradation products have been adsorbed into the zone and have accumulated to concentrations that are toxic to microorganisms used in microbial enhanced oil recovery and/or bioremediation processes, and thereby have formed a toxic zone, and b) adding an inoculum of microorganisms wherein the microorganisms comprise one or more species of: Comamonas, Fusibacter, Marinobacterium, Petrotoga, Shewanella, Pseudomonas, Vibrio, Petrotoga, Thauera , and Microbulbifer useful in microbial enhanced oil recovery to the water injection well;",
"wherein the corrosion inhibitor comprises an organic compound selected from the group consisting of organic phosphonates, organic nitrogen compounds such as amines, organic acids and their salts and esters, carboxylic acids and their salts and esters, sulfonic acids and their salts.",
"BRIEF DESCRIPTION OF THE FIGURES [0017] FIG. 1 is the schematic representation of a water injection well and the subterranean sites adjacent to the water injection well.",
"( 1 ) is the flow of injection water into the well casing ( 7 ), ( 2 and 3 ) are rock layers, ( 4 ) is the perforations in the casing, ( 5 ) is the well bore, ( 6 ) is the face of the rock layer made by the well bore, ( 7 ) is the well casing, ( 8 ) is one side of the watered zone that is axis-symmetric with the injection well, shown by a dotted box in the rock layer ( 3 ).",
"[0018] FIG. 2 is the schematic of a model system used to simulate formation of a toxic zone.",
"( 9 ) is a long slim tube;",
"( 10 ) is a pressure vessel to constrain the slim tube;",
"( 11 and 12 ) are the opposite ends of the pressurized vessel;",
"( 13 ) is a pump;",
"( 14 ) is the feed reservoir;",
"( 15 ) is the water inlet for the pressure vessel;",
"( 16 ) is the back pressure regulator;",
"( 17 ) is the high pressure air supply;",
"( 18 ) is an inlet fitting connecting the slim tube inside the pressure vessel to the pump and pressure transducers;",
"( 21 ) is an outlet fitting connecting the slim tube inside the pressure vessel to the back pressure regulator and the low side of the differential pressure transducer;",
"( 19 ) is a differential pressure transducer;",
"and ( 20 ) is an absolute pressure transducer.",
"[0019] FIG. 3 depicts titration of amine coated core sand;",
"♦ represent amine coated sand and □ represent first derivative of the titration curve (central differences).",
"[0020] FIG. 4 depicts titration of brine and core sand with 1N HCl;",
"▪ represent brine #1 with 10 grams of core sand;",
"diamonds ♦ represent brine #1 only;",
"represents the slope of brine #1 with 10 grams of core sand;",
"and Δ represents the slope of brine #1 only.",
"[0021] FIG. 5 depicts titration of brine and core sand with 10% nitric acid;",
"♦ represent the concentration of amine observed in solution for a given pH.",
"[0022] FIG. 6 depicts titration of brine and core sand with 10% acetic acid;",
"♦ represent the concentration of amine observed in solution for a given pH.",
"DETAILED DESCRIPTION OF THE INVENTION [0023] In one aspect, the present invention is a method for detoxifying the corrosion inhibitors and their degradation products in a subterranean site adjacent to a water injection well of an oil well site.",
"Applicants have found that oil recovery processing aids—such as corrosion inhibitors, for example—can accumulate in the area adjacent to the water injection well and build to concentrations that are toxic to microorganisms used in MEOR or bioremediation.",
"As the term is used herein, “detoxifying”",
"or “detoxification of”",
"a water injection site means removing or reducing the toxicity caused by corrosion inhibitors and their degradation products to microorganisms to allow their growth and activity of said microorganisms, used in MEOR or bioremediation.",
"[0024] For the purposes of the present invention, the term “toxic zone”",
"refers to a subterranean site adjacent to the water injection well comprising toxic concentrations of agents such as corrosion inhibitors or their degraded products which have adverse effects on growth and metabolic activities of microorganisms used in MEOR and/or bioremediation.",
"A toxic agent, as the term is used herein, is any chemical or biological agent that adversely affects growth and metabolic functions of microorganisms used in MEOR and/or bioremediation.",
"[0025] FIG. 1 is a schematic of a subterranean site adjacent to a water injection well.",
"The injection water ( 1 ) flows into the well casing ( 7 ) which is inside the well bore ( 5 ) drilled through rock layers ( 2 and 3 ).",
"A gap exists between the well casing ( 7 ) and the face ( 6 ) of the rock layer made by the well bore ( 5 ).",
"Rock layer ( 2 ) represents impermeable rock above and below a permeable rock ( 3 ) that holds or traps the oil.",
"The injection water ( 1 ) flows down the well casing ( 7 ) and passes through perforations in the casing ( 5 ) and into fractures ( 4 ) in the permeable rock ( 3 ).",
"This injection water then flows through the permeable rock layer ( 3 ) and displaces oil from a watered zone ( 8 ) adjacent to the well bore.",
"This zone extends radially out from the well bore ( 5 ) in all directions in the permeable rock layer ( 3 ).",
"While the volume of permeable rock ( 3 ) encompassed by the dash line ( 8 ) is illustrated only on one side of the well bore it actually exists on all sides of the well bore.",
"This watered zone represents the subterranean site adjacent to the water injection well.",
"[0026] Corrosion inhibitors that can accumulate to levels that are toxic to microorganisms used in MEOR are, for example: inorganic corrosion inhibitors such as chlorine, hypochlorite, bromine, hypobromide and chlorine dioxide.",
"Those used to combat corrosion caused by SRB microorganisms include, but are not limited to: nitrates (e.g., calcium or sodium salts), nitrite, molybdate, (or a combination of nitrate, nitrite and molybdate), anthraquinone, phosphates, salts containing chrome and zinc and other inorganics, including hydrazine and sodium sulfite (Sanders and Sturman, chapter 9, page 191, in: “Petroleum microbiology”",
"page 191, supra and Schwermer, C. U., et al.",
", Appl.",
"Environ.",
"Microbiol.",
", 74: 2841-2851, 2008).",
"[0027] Organic compounds used as corrosion inhibitors include: acetylenic alcohols, organic azoles, gluteraldehyde, tetrahydroxymethyl phophonium sulfate (THPS), bisthiocyanate acrolein, dodecylguanine hydrochloride, formaldehyde, chlorophenols, organic oxygen scavengers and various nonionic surfactants.",
"[0028] Other organic corrosion inhibitors include, but are not limited to: organic phosphonates, organic nitrogen compounds including primary, secondary, tertiary or quaternary ammonium compounds (hereinafter referred to generically as “amines”), organic acids and their salts and esters, carboxylic acids and their salts and esters, sulfonic acids and their salts.",
"[0029] Applicants have determined that corrosion inhibitors can accumulate by adsorption into or on the subterranean site (e.g., sand stone, unconsolidated sand or limestone) or into the oil that has been trapped in the oil reservoir subterranean site.",
"Long-term addition of these chemicals results in their accumulation and formation of a toxic zone in subterranean sites adjacent to the water well with adverse effects on microbial inocula intended for MEOR and/or bioremediation applications.",
"[0030] A model system to simulate formation of a toxic zone can be used to study its effects on the survival of microorganisms.",
"For example, a model system called a slim tube can be set up and packed with core sand from an oil well site.",
"The model system as described herein can be set up using tubing, valves and fittings compatible with the crude oil or the hydraulic solution used that can withstand the range of applied pressure during the process.",
"An absolute pressure transducer, differential pressure transducer and back pressure regulator for Example made by (Cole Plamer, Vernon hill, IL and Serta, Boxborough, Mass) are required and are commercially available to those skilled in the art.",
"[0031] The model toxic zone can be established using solutions of amines and/or amine mixtures and flushing them through a tube packed with core sand from an oil reservoir.",
"Other corrosion inhibitors suitable for use in constructing a model can comprise organic phosphonates or anthraquinone or phosphates.",
"The concentration of the corrosion inhibitors used to create the model toxic zone may be from 0.01 to 100 parts per million.",
"[0032] Detoxification of the toxic zone involves degradation, desorption or dispersion of the accumulated toxic chemicals or agents using detoxifying agents.",
"The term “detoxifying agent”",
"therefore refers to any chemical that either disperses or destroys the toxic chemicals and agents described herein and renders them non-toxic to microorganisms.",
"[0033] Detoxification of the chemicals accumulated in the toxic zone may be achieved using a degradation agent.",
"A degradation agent, as the term is used herein, is an agent that destroys or assists in the destruction of toxic agents found in the toxic zone.",
"Degradation agents can include, for example, strong oxidizers that chemically react with corrosion inhibitors when added to the injection water and degrade them into less toxic or non-toxic products.",
"Degradation agents include strong oxidizing agents such as, for example, nitrates, nitrites, chlorates, percholorates and chlorites.",
"[0034] Detoxification of the chemicals accumulated at the toxic zone may also be achieved using a dispersing agent.",
"A “dispersing agent”",
"as the term is used herein includes any chemical that lowers the pH of the solution, ionizes the amines and solubilizes them into the water during water flooding and allows for natural dispersion and diffusion to lower the concentration where it is no longer toxic to MEOR or bioremediation microorganisms.",
"For example, amines are fairly non-reactive under mild conditions, however, they become ionized at lower pH.",
"Thus treatment of the amines with an acid increases their solubility and releases them from oil and/or from rocks and disperses them from the toxic zone.",
"The solubilized amines may therefore enter into the water flowing through the well.",
"A combination of radial flow, dispersion and desorption may allow the solubilized amines to be diluted and dispersed over a large area (from at least 10 to about 200 feet (from at least 3 meters to about 7 meters)) of the oil well.",
"Following dilution and dispersion of the amines over a much larger area, their concentrations within the subterranean site of the well would have been consequently reduced to non-toxic levels for MEOR or bioremediation microorganisms.",
"However, even if the amines concentrations were still at toxic levels, the toxic zone in the subterranean site adjacent to the injector well will have become non-toxic to microorganisms.",
"Thus, the microbial inoculum may pass through the subterranean site adjacent to the water injection well without encountering toxic levels of the amines.",
"[0035] In another embodiment, hydrogen peroxide may be added to the toxic zone, as both a degradation and a dispersing agent, from about 1,000 parts per million to 70,000 parts per million by volume of water.",
"In another embodiment, perchlorates may be added, as both a degradation and a dispersing agent, from about 1 parts per million to about 10,000 parts per million.",
"[0036] In another embodiment, any acid capable of lowering the pH at least 1 unit less than the equivalence point of the amine (as measured in the Examples below) may be used.",
"The acid used to ionize the amines may include, but is not limited to, nitric acid, acetic acid, oxalic acid, hydrofluoric acid, and hydrochloric acid.",
"Acid may be added from about 0.1 weight % to about 20 weight % to the water that is being pumped into the toxic zone.",
"[0037] In a MEOR process, viable microorganisms are added to the water being injected into the water injection well.",
"The term “inoculum of microorganisms”",
"refers to the concentration of viable microorganisms added.",
"These microorganisms colonize, that is to grow and propagate, at the subterranean sites adjacent to the water injection well to perform their MEOR.",
"[0038] Microorganisms useful for this application may comprise classes of facultative aerobes, obligate anaerobes and denitrifiers.",
"The inoculum may comprise of only one particular species or may comprise two or more species of the same genera or a combination of different genera of microorganisms.",
"[0039] The inoculum may be produced under aerobic or anaerobic conditions depending on the particular microorganism(s) used.",
"Techniques and various suitable growth media for growth and maintenance of aerobic and anaerobic cultures are well known in the art and have been described in “Manual of Industrial Microbiology and Biotechnology”",
"(A.",
"L. Demain and N. A. Solomon, ASM Press, Washington, D.C., 1986) and “Isolation of Biotechnological Organisms from Nature”, (Labeda, D. P. ed.",
"p 117-140, McGraw-Hill Publishers, 1990).",
"[0040] Examples of microorganisms useful in MEOR in this application include, but are not limited to: Comamonas terrigena, Fusibacter paucivorans, Marinobacterium georgiense, Petrotoga miotherma, Shewanella putrefaciens, Pseudomonas stutzeri, Vibrio alginolyticus, Thauera aromatica, Thauera chlorobenzoica and Microbulbifer hydrolyticus.",
"[0041] In one embodiment an inoculum of Shewanella putrefaciens (ATCC PTA-8822) may be used to inoculate the slim tube test.",
"In another embodiment Pseudomonas stutzeri (ATCC PTA8823) may be used to inoculate the slim tube.",
"In another embodiment Thauera aromatica (ATCC9497) may be used to inoculate the slim tube.",
"[0042] The inoculum of microorganisms useful for bioremediation may comprise, but are not limited to, various species of: Corynebacteria, Pseudomonas, Achromobacter, Acinetobacter, Arthrobacter, Bacillus, Nocardia, Vibrio , etc.",
"Additional useful microorganisms for bioremediation are known and have been cited, for example, in Table 1 of U.S. Pat. No. 5,756,304, columns 30 and 31.",
"[0043] The inoculum for injecting into the water well injection site may comprise one or more of the microorganisms listed above.",
"EXAMPLES [0044] The present invention is further defined in the following Examples.",
"It should be understood that these Examples, while indicating preferred embodiments of the invention, are given by way of illustration only.",
"From the above discussion and these Examples, one skilled in the art can ascertain the essential characteristics of this invention, and make various changes and modifications to the invention to adapt it to various uses and conditions.",
"General Methods Chemicals and Materials [0045] All reagents, and materials used for the growth and maintenance of microbial cells were obtained from Aldrich Chemicals (Milwaukee, Wis.), DIFCO Laboratories (Detroit, Mich.), GIBCO/BRL (Gaithersburg, Md.), or Sigma Chemical Company (St. Louis, Mo.), unless otherwise specified.",
"Amines Analysis [0046] Concentration of amines, in media and water, were analyzed by gas chromatography (GC).",
"An Agilent Model 5890 (Agilent, Wilmington, Del.), GC equipped with a flame photoionization detector and a split/splitless injector, a DB-FFAP column (30 meter length×0.32 millimeter (mm) depth×0.25 micrometer particle size).",
"The equipment had an Agilent ALS Autoinjector, 6890 Model Series with a 10 milliliter (ml) syringe.",
"The system was calibrated using a sample of N,N-Dimethyl-1-Dodecaneamine (Aldrich).",
"Helium was used as the carrier gas.",
"A temperature gradient of 50 degrees Celsius (° C.) to 250° C. at 30° C. increase per minute (min) was used.",
"Retention times (in minutes, min) for various chemicals of interest included: N,N-Dimethyl-1-Dodecaneamine (8.08 min);",
"N,N-Dimethyl-1-Tetradecaneamine (8.85 min);",
"N,N-Dimethyl-1-Hexadecane-amine (9.90 min);",
"N,N-Dimethyl-1-Octadecaneamine (10.26 min) and N-Methyl,N-Benzyl)-1-Tetradecaneamine (11.40 min).",
"Example 1 Establishing a Toxic Zone in Core Sand from an Oil Well Using a Mixture of Amines in a Model System [0047] A sample of the sand obtained from the Schrader Bluff formation at the Milne Point Unit of the Alaska North Slope was cleaned by washing with a solvent made up of a 50/50 (volume/volume) mixture of methanol and toluene.",
"The solvent was subsequently drained and then evaporated off the core sand to produce clean, dry, flow able core sand.",
"This core sand was sieved to remove particles with less than one micrometer in size and was then packed tightly into a four foot (121.92 cm) long flexible slim tube ( 9 ) and compacted by vibration using a laboratory engraver.",
"Both ends of the slim tubes were capped to keep the core sand in it.",
"The complete apparatus is shown in FIG. 2 .",
"Tubing that can sustain the amount of pressures used in the slim tube, was connected to the end caps.",
"The slim tube ( 9 ) was mounted into the pressure vessel ( 10 ) with tubing passing through the ends ( 11 and 12 ) of the pressure vessel using pressure fittings ( 18 and 21 ).",
"Additional fittings and tubing were used to connect the inlet of the slim tube ( 11 ) to a pressure pump ( 13 ) and a feed reservoir ( 14 ).",
"[0048] Additional fittings and tubing connected the inlet of the slim tube to an absolute pressure transducer ( 20 ) and the high pressure side of a differential pressure transducer ( 19 ).",
"Fittings and tubing connected the outlet of the slim tube ( 12 ) to the low pressure side of a differential pressure transducer ( 19 ) and to a back pressure regulator ( 16 ).",
"The signals from the differential pressure and the absolute pressure transducer were ported to a computer and the pressure readings were monitored and periodically recorded.",
"The pressure vessel ( 10 ) around the slim tube was filled with water through a water port ( 15 ).",
"This water was then slowly pressurized with air ( 17 ) to a pressure of about 105 per square inch (psi) (0.72 mega Pascal) while brine #1 from the feed reservoir ( 14 ) (Table 1) flowed through the slim tube and left the slim tube through the back pressure regulator ( 16 ).",
"This operation was performed such that the pressure in the slim tube was always 5 to 20 psi (0.034-0.137 mega Pascal) below the pressure in the pressure vessel ( 10 ).",
"[0000] TABLE 1 Ingredients of Brine #1 (no nutrient brine - gram per liter (gr/L) of tap water NaHCO 3 1.38 grams (gr) CaCl 2 *6H 2 O 0.39 gr MgCl 2 *6H 2 O 0.220 gr KCl 0.090 gr NaCl 11.60 gr NaHCO 3 1.38 gr Trace metals 1 ml Trace vitamins 1 ml Na 3 (PO 4 ) 0.017 gr (=10 parts per million (ppm) PO 4 ) NH4Cl 0.029 gr (=10 ppm NH 4 ) Acetate 0.2 gr (200 ppm acetate) The pH of brine #1 was adjusted to 7.0 with either HCl or NaOH and the solution was filter sterilized.",
"[0000] TABLE 2 Concentration of the amines added to Brine #1 Minor other NN-Dimethyl-1- NN-Dimethyl-1- NN-Dimethyl- N-methylN- amine amine Dodecaneamine tetradecaneamine Methanethioamide ??",
"Caprolactam Benzyl-1-tetradecaneamine Sample PPM PPM PPM PPM PPM PPM PPM Brine #1 w/ 25 124 23 1 0 0 2 amine [0049] Once the pressure inside and outside the slim tube was established, one pore volume of the crude oil from an oil reservoir of the Milne Point Unit of the Alaskan North Slope was pumped into the slim tube.",
"This process was performed in several hours (h).",
"Once the crude oil had saturated the core sand in the slim tube and was observed in the effluent, the flow was stopped and the oil was allowed to age in the core sand for 3 weeks.",
"At the end of this time, brine #1 was pumped through the slim tube at a rate of ˜1.5-3.5 milliliter per hour (ml/h) (˜1 pore volume every 20 h).",
"Samples were taken from the effluent and the concentration of natural microflora in them was determined.",
"[0050] After 51 pore volumes of flow through the slim tube the concentration of natural microflora in the system was about 1×10 7 colony forming units per milliliter (CFU/ml).",
"At this point, a mixture of amines (hereafter amines/brine mixture) was added at 150 ppm concentration to brine #1.",
"The approximate composition of the mixture of amines (Table 2) consisted of 7 different amine components that were identified.",
"Five were identified by Mass Spectrometry (Agilent Technologies, Inc. Santa Clara, Calif.) as N-N-dimethyl-1-dodecaneamine, N-N-dimethyl-1-tetradecane-amine, N-N-dimethyl-methane-thioamide, caprolactam and N-methyl-N-benzyl-1-tetradecaneamine.",
"Two of the components were identified as amines but specific chemical formulas could not be assigned to them because the Mass Spectral Fragmentation patterns could not be deciphered.",
"These are labeled in Table 2 as “minor amine”",
"and “other amine.”",
"Analysis of the effluent from the slim tube did not indicate presence of any amines in it.",
"The experiment was continued by pumping 150 ppm of the mixture of amines in brine #1 through the slim tube.",
"[0051] After 77 pore volumes of the mixture of brine #1 with 150 ppm of mixture of amines was pumped into the slim tube no amines were observed in the effluent.",
"[0052] After 80 pore volumes of the mixture of brine #1 with 150 ppm of mixture of amines was pumped into the slim tube a total of about 1 gr of the mixture of amines had flowed through the slim tube.",
"At this point, 80 ppm of amines was finally observed in the effluent of the slim tube.",
"This very long delay in seeing the amines in the effluent means that virtually all the amines had been trapped in the slim tube.",
"In addition, at this time, no natural microflora could be seen in the effluent indicating that the slim tube had become toxic enough to kill all existing microflora.",
"At this point, pumping the amines-free brine#1 was started in an attempt to flush the amines out of the slim tube and to make it less toxic.",
"[0053] After 24 pore volumes of the amines-free brine#1 had been pumped through the slim tube, 51 ppm of amines was detected in the effluent.",
"The slim tube was then inoculated with one pore volume of Shewanella putrefaciens (ATCC PTA-8822) at a concentration of approximately 1×10 9 CFU/ml.",
"This inoculation was not allowed to remain in the slim tube.",
"Instead, amines-free brine#1 was flushed through the slim tube immediately after the inoculation.",
"Consequently the microbes resided in the slim tube for only a few hours during the transit through it.",
"Thus, it was anticipated that the microorganisms'",
"concentration in the effluent could be measured in the effluent eluting the slim tube.",
"However, remarkably no microorganisms (representing about a 9 log kill) were detected in the slim tube effluent despite the short residence time of the inoculum in the slim tube.",
"This experiment confirmed that a toxic zone had been established in the slim tube.",
"In a continued attempt to detoxify the slim tube, brine #1 alone was continuously pumped through it.",
"[0054] After 79 pore volumes of the amines-free brine #1 had been pumped through the slim tube, the amines concentration in the effluent of the slim tube was measured at 30 ppm.",
"The slim tube was inoculated with another pore volume of Shewanella putrefaciens (at 1×10 9 CFU/ml).",
"The CFU/ml in an effluent sample was about 1×10 4 showing more than a 5 log kill of this microorganism had occurred immediately following inoculation.",
"This experiment underlined the continued toxic effect of the amines despite extended washing of the tube with the amines-free brine#1 solution.",
"[0055] After 108 pore volumes of the amines-free brine #1 had been pumped through the slim tube, the amine concentration in the effluent was measured at 5 ppm.",
"The slim tube was inoculated with an additional one pore volume of Shewanella putrefaciens containing 1×10 9 CFU/ml.",
"The CFU/ml in the effluent sample of the slim tube immediately following inoculation indicated a 4-5 log kill of this microorganism despite the extended washing with the amines-free brine#1 and the decrease in the amines concentration in the effluent.",
"These results further confirmed the continued toxic effect of the mixture of amines accumulated in the slim tube.",
"[0056] After 143 pore volumes of the amines-free brine #1 had been pumped through the slim tube one pore volume of an inexpensive odorless mineral spirits (OMS)(Parks OMS, Zinsser Co., Inc., Somerset Jew Jersey #2035 CAS #8052-41-3) was pumped through the slim tube in an attempt to remove the remaining mixture of amines.",
"After this flush of OMS, pumping of amines-free brine #1 through the slim tube was continued.",
"[0057] After 149 pore volumes of amines-free brine #1 had been pumped through the slim tube, the amines concentration in the effluent was measured at 4 ppm and the slim tube was inoculated with an additional one pore volume of Shewanella putrefaciens (1×10 9 CFU/ml).",
"A count of microorganisms in the sample of the slim tube's effluent showed a 2-3 log kill (99 to 99.9%) despite the OMS flush and the extended washing with the amines-free brine#1.",
"These results confirmed that the toxic zone in the slim tube was still killing virtually all the microorganisms added to the tube.",
"[0058] After 168 pore volumes of the amines-free brine #1 had been pumped through the slim tube, one pore volume of a solution of 10% HCl in water was pumped through the slim tube to remove the amines.",
"After this acid wash, the amines-free brine #1 was continuously pumped through the slim tube.",
"[0059] Following the acid wash treatment, an additional 2 pore volumes of the amines-free brine #1 was pumped through the slim tube and the amines concentration in the effluent was measured at 0.5 ppm.",
"The slim tube was then inoculated with an additional one pore volume of Shewanella putrefaciens (1×10 9 CFU/ml).",
"The CFU/ml in the effluent showed about a 0.4 log kill of this microorganism.",
"These results underlined survival of more microorganisms following the acid wash of the slim tube and the effectiveness of using an acid to detoxify the toxic zone in the slim tube.",
"Table 3 below summarizes results of the various tests described above.",
"[0000] TABLE 3 Summary of the amount of amine observed in the slim tube's effluent and the fraction of the microorganisms killed (log kill) during residence in the slim tube.",
"Total Pore volume of fluid ppm pumped amines log kill through slim in the after tube effluent inoculating 51 0 0 131 80.5 nd amines flood stopped 155 51.1 9.6 210 29.5 5.3 (at least) 239 4.7 4.5 (at least) 274 OMS flooded ~1 pore volume 280 4.2 2.4 299 10% HCL flooded for 1 PV 301 0.5 0.4 PV = pore volume;",
"nd = not detected Example 2 Removal of N N-Dimethyl-1-Dodecanamine from Core Sand Through their Ionization at Low pH Using Hydrochloric Acid [0060] 38 milligrams (mg) of N N-Dimethyl-1-Dodecanamine (hereafter referred to as “the amine”) was added to 10.210 gr of Pentane.",
"This solution was added to 10.1845 gr of specific sand layers (Oa and Ob) obtained from the Schrader Bluff formation of the Milne Point Unit of the Alaskan North slope.",
"The oil content of the sand was first removed using a mixture of methanol and toluene (50/50, volume/volume) as solvent washes.",
"The solvent mixture was subsequently evaporated off the core sand to produce clean, dry, flowable core sand.",
"This sand was mixed with the amine and pentane solution to produce a slurry.",
"This slurry was thoroughly mixed and the pentane was evaporated off leaving the amine on the sand (hereafter referred to as sand/amine mixture).",
"100 ml of brine #2 (Table 3) was added to the sand/amine mixture to create the sand/amine/brine mixture.",
"The initial pH of the sand/amine/brine mixture was 8.4.",
"The concentration of the amine in the water should have been 380 ppm if all the amine were dissolved in brine #2.",
"Analysis of a sample of sand/amine/brine mixture by GC did not reveal the presence of any amines in the test sample (i.e., the amine conc.",
"was ˜<1 ppm).",
"The fact that the amine was not detected underlined its strong binding to the sand particles.",
"0.1 ml of 1 normal (N) HCl was added to this solution, and the pH and the amine concentration was measured again.",
"This step was repeated several times and the analyses results are shown in both Table 4 and in FIG. 3 .",
"Complete ionization and solubilization of the amine in the water was observed at pH below ˜6.0.",
"This is a surprising finding since the pKa of HCl is −6.2 (Langes Handbook of Chemistry, 14 th edition, page 8.14, 1992, McGraw-Hill, Inc., New York).",
"Therefore, the concentration of the HCl required for this step to completely ionize the amine and removed it from the toxic core sand may be further reduced several orders of magnitude from the 10% concentration used in this example.",
"The data underlines the remarkable efficiency of an acid at ionizing and removing the amine from the sand.",
"[0000] TABLE 3 Composition of brine #2 (gr/L of deionized water) NaHCO 3 1.38 gr CaCl 2 *6H 2 O 0.39 gr MgCl 2 *6H 2 O 0.220 gr KCl 0.090 gr NaCl 11.60 gr [0000] TABLE 4 Amine concentration measured in Example 2 N-N- First dimethyl-1- derivative dodeanamine (change in (ppm) in slim amine/change 1N HCl sample tube effluent in pH) pH (ml) Amine titrate st 0.00 8.14 0.00 Amine titrate 1 46.41 63.75 7.37 0.10 Amine titrate 2 59.29 63.42 7.21 0.10 Amine titrate 3 67.97 24.34 7.03 0.10 Amine titrate 4 74.38 160.35 6.59 0.10 Amine titrate 5 212.28 412.18 6.13 0.10 Amine titrate 6 288.72 679.86 6.07 0.10 Amine titrate 7 273.47 −148.78 6.04 0.05 Amine titrate 8 275.33 119.35 5.98 0.05 Amine titrate 9 303.31 65.90 5.79 0.05 Amine titrate 10 314.21 15.17 5.39 0.05 Amine titrate 11 328.48 3.24 4.13 0.05 Amine titrate 12 321.33 11.80 3.19 0.05 Amine titrate 13 342.88 47.42 2.91 0.05 Amine titrate 14 342.67 −6.52 2.74 0.05 Amine titrate 15 340.92 79.86 2.61 0.05 Amine titrate 16 369.02 80.22 2.41 0.10 Amine titrate 17 368.19 2.25 2.27 0.10 Amine titrate 18 369.54 7.51 2.18 0.10 Amine titrate 19 369.47 0.12 2.10 0.10 Amine titrate 20 369.56 2.04 0.10 Example 3 Capacity of Core Sand to Neutralize Acid A. Titration of Brine #2 in the Absence of Core Sand [0061] The intent of this experiment was to determine the capacity of the core sand described in Example 2 to neutralize the HCl intended to ionize the amine accumulated in the sand.",
"[0062] To set up a control test, 100 ml of brine #2 was titrated with 1 N HCl to initial pH of 8.1.",
"An aliquot (0.1 ml) of 1N HCl was added to the brine #2 and the pH was measured.",
"The HCl addition was repeated several times and the pH was measured after each addition.",
"Results of these analyses are shown in both Table 5 and in FIG. 4 .",
"The data indicated that about 2.25 milliequivalents of HCl were needed to achieve the equivalence point of about pH 4 corresponding to about 100% recovery of the carbonate present in brine #2.",
"[0000] TABLE 5 Titration of synthetic injection brine #2 in the absence of the amine First derivative of 1N HCl sample pH pH (ml) Addition 1 8.10 0.00 Addition 2 7.67 0.73 0.10 Addition 3 7.37 0.49 0.10 Addition 4 7.18 0.35 0.10 Addition 5 7.02 0.29 0.10 Addition 6 6.89 0.23 0.10 Addition 7 6.79 0.21 0.10 Addition 8 6.68 0.19 0.10 Addition 9 6.60 0.17 0.10 Addition 10 6.51 0.15 0.10 Addition 11 6.45 0.15 0.10 Addition 12 6.36 0.18 0.10 Addition 13 6.27 0.18 0.10 Addition 14 6.18 0.18 0.10 Addition 15 6.09 0.17 0.10 Addition 16 6.01 0.17 0.10 Addition 17 5.92 0.18 0.10 Addition 18 5.83 0.19 0.10 Addition 19 5.73 0.33 0.10 Addition 20 5.50 0.32 0.10 Addition 21 5.41 0.33 0.10 Addition 22 5.17 0.74 0.10 Addition 23 4.67 1.94 0.10 Addition 24 3.23 1.86 0.10 Addition 25 2.81 0.62 0.10 Addition 26 2.61 0.36 0.10 Addition 27 2.45 0.25 0.10 Addition 28 2.36 0.17 0.10 Addition 29 2.28 0.10 B. Titration of Brine #2 with Core Sand [0063] 100 ml of brine #2 plus 10 gr of the same core sand (brine/sand mixture) used in Example 2, was titrated with 1N HCl.",
"The initial pH of the brine/sand mixture was 7.88.",
"0.1 ml aliquots of 1N HCl were added to this mixture repeatedly, and the pH was measured after each HCl addition.",
"The results shown in both Table 6 and in FIG. 4 indicated that addition of 0.3 milliequivalents of HCl was needed to achieve the equivalence point with 10 gr of sand present.",
"The data obtained in this experiment underlines the slight capacity of the core sand to neutralize the added HCl.",
"Consequently a small concentration of an acid, such as HCl, ionized the amine associated with the core sand without getting neutralized by reaction with the sand.",
"[0000] TABLE 6 Titration of brine #2 and 10 gr of core sand Brine contained 1.87 gr NaHCO 3 2.60 ml of 1N Used 10.103 gr of core sand Sample HCL at pH Slope of pH (first derivative) ml 1N HCl 1 7.88 0.00 2 7.55 0.53 0.10 3 7.35 0.36 0.10 4 7.19 0.30 0.10 5 7.05 0.24 0.10 6 6.95 0.20 0.10 7 6.85 0.18 0.10 8 6.77 0.18 0.10 9 6.67 0.17 0.10 10 6.60 0.14 0.10 11 6.53 0.14 0.10 12 6.46 0.13 0.10 13 6.40 0.12 0.10 14 6.34 0.13 0.10 15 6.27 0.13 0.10 16 6.21 0.13 0.10 17 6.14 0.15 0.10 18 6.06 0.16 0.10 19 5.98 0.16 0.10 20 5.90 0.17 0.10 21 5.81 0.21 0.10 22 5.69 0.29 0.10 23 5.52 0.34 0.10 24 5.35 0.45 0.10 25 5.07 0.80 0.10 26 4.55 1.14 0.10 27 3.93 1.13 0.10 28 3.42 0.86 0.10 29 3.07 0.52 0.10 30 2.90 0.33 0.10 31 2.74 0.24 0.10 32 2.66 0.29 0.10 33 2.45 0.34 0.20 34 2.32 0.23 0.20 35 2.22 0.18 0.20 36 2.14 0.20 Example 4 Removal of N—N-Dimethyl-1-Dodecanamine from Core Sand Through their Ionization at Low pH Using 10% Nitric Acid [0064] The procedure outlined in Example 2 was used to produce the sand/amine mixture except that 519 mg of the amine, 10 gr of Pentane.",
"and 60.062 gr of sand from the Oa and Ob layers were used.",
"29.065 gr of this sand/amine mixture was added to 100 ml of brine #2 (Table 3) to create the sand/amine/brine mixture.",
"The initial pH of the sand/amine/brine mixture was 8.28.",
"The concentration of the amine in the water should have been about 2000 ppm if all the amine was dissolved in brine #2.",
"Instead, analysis of a sample of brine #2 in contact with the sand/amine/brine mixture as described above showed that the amine concentration was ˜85 ppm, i.e., far less than what was expected.",
"The fact that only a small amount of the amine was detected in brine #2 underlined the strong binding of the amine to the sand particles.",
"0.1 ml of 10 weight percent (wt %) nitric acid in water was added to this solution, and the pH and the amine concentration were measured again.",
"This step was repeated several times and the analyses results are shown in both Table 7 and in FIG. 5 .",
"Complete ionization and solubilization in the water of the amine was observed at a pH below ˜6.7.",
"This is a surprising finding since the pKa of nitric acid is −1.37 (Langes Handbook of Chemistry, 14 th edition, page 8.15, 1992, McGraw-Hill, Inc., New York), the concentration of the nitric acid required for this step may be further reduced several orders of magnitude from the 10 wt % used in this experiment without any negative impact on removal of the amines from the core sand.",
"[0000] TABLE 7 Amine concentration measured in Example 4 ppm N-N- dimethyl-1- sample dodeanamine pH ml 10% HNO 3 start 85 8.28 0 1 110 8.13 0.1 2 211 7.72 0.1 3 216 7.42 0.1 4 235 7.25 0.1 5 540 7.2 0.1 6 745 7.29 0.1 7 1153 7.33 0.1 8 1210 7.29 0.1 9 1327 7.18 0.1 10 1315 7.11 0.1 11 1413 6.99 0.1 12 1667 6.85 0.1 13 1897 6.73 0.1 14 1853 6.64 0.1 15 1858 6.59 0.1 16 1788 6.28 0.2 17 1822 5.8 0.2 18 1975 3.46 0.2 Example 5 Removal of N—N-Dimethyl-1-Dodecanamine from Core Sand Through its Ionization at Low pH Using 10% Acetic Acid [0065] The same procedure outlined in Example 4 was repeated here to produce the sand/amine mixture.",
"30.85 grams (gr) of the sand/amine mixture was added to 100 ml of brine #2 (Table 3) to create the sand/amine/brine mixture.",
"The initial pH of the sand/amine/brine mixture was 8.52.",
"The concentration of the amine in the water should have been about 2000 ppm if all the amine were dissolved in brine #2.",
"Instead, analysis of brine #2 in contact with the sand/amine/brine mixture, as described above, showed that the amine concentration was ˜67 ppm, i.e., far less than what was expected.",
"The fact that only a small amount of the amine was detected in the brine #2 underlined the strong binding of the amine to the sand particles.",
"0.1 ml of 10 wt % acetic acid was added to this solution, and the pH and the amine concentration were measured again.",
"This step was repeated several times and the analyses results are shown in both Table 8 and in FIG. 6 .",
"Complete ionization and solubilization in the water of the amine was observed at pH below ˜6.7.",
"This is a surprising finding since the pKa of acetic acid is 4.756 (Langes Handbook of Chemistry, 14 th edition, page 8.19, 1992, McGraw-Hill, Inc., New York).",
"Consequently, the concentration of the acetic acid required for this step may be further reduced significantly from what was used in this example without any negative impact on removal of the amine from the core sand.",
"[0066] The observations described above illustrate that a weak organic acid, like acetic acid can be as effective as a strong inorganic acid, like hydrochloric acid, at ionizing and separating the amines from the toxic core sand.",
"It can therefore be concluded that to remove the toxic zone from a subterranean site, any acid that decreases the pH of a solution below about 6.7 can be used.",
"[0000] TABLE 8 Amine concentration measured in Example ppm N-N- dimethyl-1- sample dodeanamine pH ml 10% acetic acid start 67 8.52 0 1 63 8.01 0.1 2 107 7.41 0.1 3 215 7.4 0.1 4 497 7.37 0.1 5 512 7.23 0.1 6 969 7.12 0.1 7 1239 6.98 0.1 8 1453 6.89 0.1 9 1583 6.75 0.1 10 1579 6.56 0.1 11 1616 6.39 0.1 12 1759 6.4 0.1 13 1736 6.02 0.2 14 1718 5.4 0.2 15 1743 5.04 0.2 16 1931 4.86 0.2 17 1995 4.73 0.2 18 1913 4.61 0.2 19 1881 4.52 0.2 20 1837 4.43 0.2 21 1885 4.36 0.3"
] |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for dispensing liquids and more particularly to a dispensing valve assembly for use with pressurized and non-pressurized beverages in disposable containers.
2. Description of the Prior Art
It has become common to supply disposable beverage containers for carbonated beverages and the like which are formed from thin plastic and are available in two and three liter sizes. Once a larger container is opened, carbonation tends to be lost. In many instances, difficulty is experienced in removing and replacing the sealing cap sufficiently tightly to prevent gradual loss of carbonation during storage. These problems result in waste of beverages and reluctance of consumers to purchase the larger sizes.
Thus, there is a need for a simple, low cost dispensing system which can easily dispense carbonated beverages from large containers and will permit storage of the beverages for long periods of time without loss of carbonation.
SUMMARY OF THE INVENTION
My invention incorporates a simple dual function valve disposed in a dispensing valve assembly which is attached to the container after removal of the original cap. To draw beverage from the container, it is installed in a stand in a tilted or inverted attitude to produce a gravity feed with the dispensing valve at the lowest point. The dispensing valve includes a first passage having a vent tube projecting therefrom into the container such that the distal end of the tube projects into the ullage volume during use and a vent valve between the passage and a spout. A second passage in the valve communicates with the beverage fluid and includes a fluid valve connecting the second passage to the spout. A dispensing handle included in the valve assembly is arranged such that movement of the handle first opens the vent valve to the ullage tube and thereafter opens the fluid valve to the beverage fluid permitting fluid to flow through the spout into a glass or other desired container.
The ullage tube serves two functions. First, where escaped carbon dioxide gas has collected in the ullage volume, the ullage tube allows this gas to be vented to the outside air to prevent forceful ejection of the fluid from the spout which could cause splashing or spillage of the beverage. Secondly, the ullage tube vents makeup air to the ullage volume to prevent a thin plastic container from collapsing. When the lever is not depressed, both valves are closed and the container may be removed from the stand and stored vertically with the container in the refrigerator or other storage means without further escape of the carbon dioxide gases from the beverage.
The holder or stand with which the dispensing valve assembly is to be used includes a slot which matches the flange on the disposable beverage containers presently available and into which the container is installed. The container and dispensing valve is thereafter held rigidly in the slot, but can be easily removed for storage.
It is therefore a principal object of my invention to provide apparatus for dispensing carbonated beverages from disposable plastic containers and for permitting storage of such beverages without further loss of carbonation.
It is another object of my invention to provide a dispensing valve assembly having sequential operation of a first valve to vent the ullage volume of the container to the outside air and a second valve to dispense the liquid beverage from the container.
It is still another object of my invention to provide an apparatus for dispensing liquids which includes a stand for holding a disposable container of liquid in an inverted or slanted position to permit gravity feed of the liquid.
It is a further object of my invention to provide an apparatus for dispensing liquids which will accommodate containers of varying size.
These and other objects and advantages of my invention will become apparent from the following detailed description when read in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a dispensing valve assembly in accordance with my invention installed on a container of a carbonated beverage;
FIG. 2 is a perspective view of a typical large beverage container having the dispensing valve assembly of my invention installed thereon and the container installed on a stand;
FIG. 3 is a partial view of the stand of FIG. 2 showing the container holding slots;
FIG. 4 is a view of the valve assembly of my invention showing the body thereof in a vertical cross-sectional view;
FIG. 5 is a view of the face of the coupling portion of the valve assembly of FIG. 4;
FIG. 6 is a horizontal cross-sectional view of the valve assemblies of FIG. 4;
FIG. 7 shows the vent valve stem and the liquid valve stem of the invention; and
FIG. 8 shows an alternative stand for use with my dispenser valve assembly which is especially suited for use in a refrigerator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, I have shown a schematic diagram illustrating the operation of my dispenser valve assembly 10. Valve assembly 10 is attached to a bottle or container of a carbonated beverage 6 in which the original container cap has been removed. A ullage vent tube 8 extends from a vent chamber 26 into the ullage volume 7 of container 5. A liquid chamber 37 is connected by a channel 9 to communicate with the liquid 6. Vent chamber 26 is maintained in a closed condition by a vent valve element 52 and compression spring 40. Similarly, fluid chamber 37 is maintained in a closed position by fluid valve element 42 and compression spring 41.
As will be understood, in the positions shown in FIG. 1, both the vent valve and fluid valve are closed and no flow of fluid will occur. An operating handle 46 is pivoted by pivot 48 such that movement of handle 46 in the direction shown by arrow A will first cause vent valve element 52 to move in the direction shown by arrow B, venting vent chamber 26 to the atmosphere via vent passage 31 and spout 15. Any carbon dioxide gas which has escaped from fluid 6 into ullage volume 7 will therefore be vented and the pressure in volume 7 will be relieved.
As handle 46 continues to move, it will contact fluid valve element 42, compressing spring 41 and opening fluid chamber 37 to the fluid passage 33. As this occurs, it will be recognized that atmospheric air is vented to ullage volume 7 permitting fluid 6 to flow by gravity through channel 9, fluid chamber 37, and out through passage 33 and spout 15 to a container. The rate of flow of the fluid can be controlled by the pressure on handle 46. When handle 46 is released, valve elements 42 and 52 will be closed by springs 40 and 41, sealing container 5 to prevent any escape of carbonation to the atmosphere.
FIG. 2 show a preferred embodiment of my invention having dispensing valve assembly 10 installed on the neck of a container 5 and installed on a stand 60 having a receiving slot assembly 62 attached thereto. Conventional containers of carbonated beverage such as container 5 are provided with heavy flange 9 between the neck and the cap threads. Advantageously, mounting slot assembly 62 permits flange 9 to be inserted therein for holding the container in place. The stand 60 is proportioned such that the center of gravity of container 5 when full is sufficiently forward such that the assembly is stable.
FIG. 3 shows a partial view of stand 60 with details of the mounting slot assembly 62. Stand 60 has a first semi-circular cutout 67 therein which matches the neck diameter of the larger disposable containers, such as container 5 of FIG. 2, and a second semi-circular cutout 69 which matches the diameter of the smaller disposable containers. A plate 62 is provided having matching cutouts 64 and 66 and is attached to stand 60 by spacer 63 thus defining a groove 65 between plate 62 and stand 60 into which flange 9 of a container will fit. As will be recognized, the smaller containers will be supported by the area formed between cutouts 66 and 69 while the larger containers will be supported by the area between cutouts 64 and 67.
Turning now to FIG. 4, a cross-sectional view of the dispensing valve assembly 10 is shown. A dual thread arrangement is provided in body portion 11 having inner threads 16 and outer threads 14 for attaching assembly 10 to a container. As will be understood, threads 16 will fit the small necked bottle cap threads while threads 14 fit the large necked bottle cap threads. An O-ring 20 provides a seal for use with the small necked bottle and O-ring 18 provides the seal for the large necked bottles, as also seen from the end view of body 11 in FIG. 5.
FIG. 4 shows the vent valve arrangement having a bore 24 for receiving the ullage vent tube 8, a vent chamber 26 and a vent valve element 52 having a valve stem 30, a valve head 34 and an O-ring 32. It will be noted that valve assembly 52 includes compression spring 40 in recess 38 coupled to valve stem 30 by D-ring 36. Spring 40 is placed under tension so as to keep valve head 34 and O-ring 32 tightly closed against the shoulders of vent chamber 26. Vent chamber 26 communicates with vent passage 31 to spout 15.
Operating handle 46 is attached to body 11 and disposed in a slot 13 in body 11. Handle 46 is pivoted by pivot 48 and contacts the end of valve stem 30 in cutout 51. Slot 13 is formed so as to act as a stop for handle 46 in the position shown. Handle 64 includes a thumb tab portion 58 and body 11 includes a finger grip portion 12. The user may thus grasp handle 46 and body 11 with the thumb and fingers, causing handle lever 50 to move forward as indicated by arrow D moving valve stem 30 in the direction as shown by arrow E thereby opening vent chamber 26 to vent passage 31. As indicated by the dashed lines, handle lever 50 will move until it contacts the bottom of slot 13. Although not shown in FIG. 4, chambers 26 and 37 are arranged side by side horizontally as best seen in FIGS. 5 and 6. As noted in the cross-sectional view of body 11 of FIG. 6 through a horizontal plane, fluid chamber 37 is essentially parallel to chamber 26 and communicates with fluid passage 33 parallel to vent passage 31 which also connects to spout 15. As may be noted from FIG. 6, spout 15 as shown in the dashed lines is elliptical in shape while passages 31 and 33 are circular.
In FIG. 6, ullage vent tube 8 is shown installed in bore 24 and communicates with chamber 26.
Details of the vent valve element 52 and fluid valve element 42 are shown in FIG. 7. Valve 52 includes a tapered head assembly 34 with O-ring 32 disposed in a groove therein. A groove 39 is provided at the other end of valve stem 30 for accepting a spring retaining D-washer as shown in FIG. 4. As previously shown, valve head 34 is installed in vent chamber 26. Tapered head 34 of valve 52 permits the user to control the flow of gas under pressure in ullage volume 7 by the degree of pressure on valve stem 30.
Fluid valve element 42 is seen to be slightly shorter than vent valve element 52 and includes a head portion 45 having an O-ring 43 disposed thereon, a stem 42 and a groove 45 for accepting a D-washer for retaining spring 41. Head 41 is installed in fluid chamber 37 with stem 47 parallel with vent valve stem 30. Lever portion 50 of handle 46 is sufficiently wide so as to contact both valve stem 30 and valve stem 47 when handle 46 is moved in the direction shown by arrow D in FIG. 4. Since stem 47 is slightly shorter than stem 40, it will be understood that lever portion 50 will open vent valve 52 before contacting the end of liquid valve stem 47. Thus, venting or escape of pressurized gas occurs before opening of the fluid valve 42.
When handle 46 is FIG. 4 is fully depressed and in the position indicated by the dashed lines, both valves will be opened and the fluid in the attached container will flow through fluid passage 33 and spout 15 to a glass or other container. Handle 46 may be temporarily locked in the unoperated position by means of a locking arm 56 pivotally attached to handle 46. Arm 56 is shown in the retracted position in FIG. 4. When extended, as indicated by the dashed lines, arm 56 contacts a concave area 57 of body 11 thereby preventing handle 46 from being depressed.
After use of the dispensing valve assembly 10, the container with the assembly in place is removed from the stand 60 and stored with the dispensing valve assembly 10 remaining on the neck of the container, ready for subsequent use. The tightly closed valves and the cap thread O-ring prevents any loss of carbonation by leakage around a cap.
Although I have disclosed a preferred stand 60 for holding the container and dispensing valve assembly of my invention in FIG. 2, an alternative design for a stand is shown in FIG. 8. Stand 70 may be noted to have the supporting sides thereof oppositely disposed from those of the stand of FIG. 2. The angle of the front portion of the stand 70 with the vertical shown as in FIG. 3 may be varied as desired to form a more compact arrangement which can be installed within a refrigerator yet would not require excessive space. In such instance, a beverage may be dispensed by simply opening a refrigerator door and filling a glass or other container without removing the beverage container and stand from the refrigerator.
Although I have shown specific embodiments of my invention for illustrative purposes, I consider that various changes can be made therein by those of skill in the art without departing from the spirit and scope of my invention. | An apparatus for dispensing carbonated beverages and the like from a container has a body portion adapted to replace a screw top cap of the container. The body portion includes a tube which will project into the ullage volume of the container and will vent to the atmosphere via a normally closed vent valve. A normally closed fluid valve is disposed in the body portion between a fluid chamber and a spout. In use the container having the body portion attached thereto is essentially inverted and supported in a stand. A dispensing lever attached to the body is depressed and sequentially opens the vent valve and the fluid valve permitting the beverage to flow through the fluid chamber, the fluid valve and the spout by gravity. | Concisely explain the essential features and purpose of the concept presented in the passage. | [
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present invention relates to an apparatus for dispensing liquids and more particularly to a dispensing valve assembly for use with pressurized and non-pressurized beverages in disposable containers.",
"Description of the Prior Art It has become common to supply disposable beverage containers for carbonated beverages and the like which are formed from thin plastic and are available in two and three liter sizes.",
"Once a larger container is opened, carbonation tends to be lost.",
"In many instances, difficulty is experienced in removing and replacing the sealing cap sufficiently tightly to prevent gradual loss of carbonation during storage.",
"These problems result in waste of beverages and reluctance of consumers to purchase the larger sizes.",
"Thus, there is a need for a simple, low cost dispensing system which can easily dispense carbonated beverages from large containers and will permit storage of the beverages for long periods of time without loss of carbonation.",
"SUMMARY OF THE INVENTION My invention incorporates a simple dual function valve disposed in a dispensing valve assembly which is attached to the container after removal of the original cap.",
"To draw beverage from the container, it is installed in a stand in a tilted or inverted attitude to produce a gravity feed with the dispensing valve at the lowest point.",
"The dispensing valve includes a first passage having a vent tube projecting therefrom into the container such that the distal end of the tube projects into the ullage volume during use and a vent valve between the passage and a spout.",
"A second passage in the valve communicates with the beverage fluid and includes a fluid valve connecting the second passage to the spout.",
"A dispensing handle included in the valve assembly is arranged such that movement of the handle first opens the vent valve to the ullage tube and thereafter opens the fluid valve to the beverage fluid permitting fluid to flow through the spout into a glass or other desired container.",
"The ullage tube serves two functions.",
"First, where escaped carbon dioxide gas has collected in the ullage volume, the ullage tube allows this gas to be vented to the outside air to prevent forceful ejection of the fluid from the spout which could cause splashing or spillage of the beverage.",
"Secondly, the ullage tube vents makeup air to the ullage volume to prevent a thin plastic container from collapsing.",
"When the lever is not depressed, both valves are closed and the container may be removed from the stand and stored vertically with the container in the refrigerator or other storage means without further escape of the carbon dioxide gases from the beverage.",
"The holder or stand with which the dispensing valve assembly is to be used includes a slot which matches the flange on the disposable beverage containers presently available and into which the container is installed.",
"The container and dispensing valve is thereafter held rigidly in the slot, but can be easily removed for storage.",
"It is therefore a principal object of my invention to provide apparatus for dispensing carbonated beverages from disposable plastic containers and for permitting storage of such beverages without further loss of carbonation.",
"It is another object of my invention to provide a dispensing valve assembly having sequential operation of a first valve to vent the ullage volume of the container to the outside air and a second valve to dispense the liquid beverage from the container.",
"It is still another object of my invention to provide an apparatus for dispensing liquids which includes a stand for holding a disposable container of liquid in an inverted or slanted position to permit gravity feed of the liquid.",
"It is a further object of my invention to provide an apparatus for dispensing liquids which will accommodate containers of varying size.",
"These and other objects and advantages of my invention will become apparent from the following detailed description when read in conjunction with the drawings.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a dispensing valve assembly in accordance with my invention installed on a container of a carbonated beverage;",
"FIG. 2 is a perspective view of a typical large beverage container having the dispensing valve assembly of my invention installed thereon and the container installed on a stand;",
"FIG. 3 is a partial view of the stand of FIG. 2 showing the container holding slots;",
"FIG. 4 is a view of the valve assembly of my invention showing the body thereof in a vertical cross-sectional view;",
"FIG. 5 is a view of the face of the coupling portion of the valve assembly of FIG. 4;",
"FIG. 6 is a horizontal cross-sectional view of the valve assemblies of FIG. 4;",
"FIG. 7 shows the vent valve stem and the liquid valve stem of the invention;",
"and FIG. 8 shows an alternative stand for use with my dispenser valve assembly which is especially suited for use in a refrigerator.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, I have shown a schematic diagram illustrating the operation of my dispenser valve assembly 10.",
"Valve assembly 10 is attached to a bottle or container of a carbonated beverage 6 in which the original container cap has been removed.",
"A ullage vent tube 8 extends from a vent chamber 26 into the ullage volume 7 of container 5.",
"A liquid chamber 37 is connected by a channel 9 to communicate with the liquid 6.",
"Vent chamber 26 is maintained in a closed condition by a vent valve element 52 and compression spring 40.",
"Similarly, fluid chamber 37 is maintained in a closed position by fluid valve element 42 and compression spring 41.",
"As will be understood, in the positions shown in FIG. 1, both the vent valve and fluid valve are closed and no flow of fluid will occur.",
"An operating handle 46 is pivoted by pivot 48 such that movement of handle 46 in the direction shown by arrow A will first cause vent valve element 52 to move in the direction shown by arrow B, venting vent chamber 26 to the atmosphere via vent passage 31 and spout 15.",
"Any carbon dioxide gas which has escaped from fluid 6 into ullage volume 7 will therefore be vented and the pressure in volume 7 will be relieved.",
"As handle 46 continues to move, it will contact fluid valve element 42, compressing spring 41 and opening fluid chamber 37 to the fluid passage 33.",
"As this occurs, it will be recognized that atmospheric air is vented to ullage volume 7 permitting fluid 6 to flow by gravity through channel 9, fluid chamber 37, and out through passage 33 and spout 15 to a container.",
"The rate of flow of the fluid can be controlled by the pressure on handle 46.",
"When handle 46 is released, valve elements 42 and 52 will be closed by springs 40 and 41, sealing container 5 to prevent any escape of carbonation to the atmosphere.",
"FIG. 2 show a preferred embodiment of my invention having dispensing valve assembly 10 installed on the neck of a container 5 and installed on a stand 60 having a receiving slot assembly 62 attached thereto.",
"Conventional containers of carbonated beverage such as container 5 are provided with heavy flange 9 between the neck and the cap threads.",
"Advantageously, mounting slot assembly 62 permits flange 9 to be inserted therein for holding the container in place.",
"The stand 60 is proportioned such that the center of gravity of container 5 when full is sufficiently forward such that the assembly is stable.",
"FIG. 3 shows a partial view of stand 60 with details of the mounting slot assembly 62.",
"Stand 60 has a first semi-circular cutout 67 therein which matches the neck diameter of the larger disposable containers, such as container 5 of FIG. 2, and a second semi-circular cutout 69 which matches the diameter of the smaller disposable containers.",
"A plate 62 is provided having matching cutouts 64 and 66 and is attached to stand 60 by spacer 63 thus defining a groove 65 between plate 62 and stand 60 into which flange 9 of a container will fit.",
"As will be recognized, the smaller containers will be supported by the area formed between cutouts 66 and 69 while the larger containers will be supported by the area between cutouts 64 and 67.",
"Turning now to FIG. 4, a cross-sectional view of the dispensing valve assembly 10 is shown.",
"A dual thread arrangement is provided in body portion 11 having inner threads 16 and outer threads 14 for attaching assembly 10 to a container.",
"As will be understood, threads 16 will fit the small necked bottle cap threads while threads 14 fit the large necked bottle cap threads.",
"An O-ring 20 provides a seal for use with the small necked bottle and O-ring 18 provides the seal for the large necked bottles, as also seen from the end view of body 11 in FIG. 5. FIG. 4 shows the vent valve arrangement having a bore 24 for receiving the ullage vent tube 8, a vent chamber 26 and a vent valve element 52 having a valve stem 30, a valve head 34 and an O-ring 32.",
"It will be noted that valve assembly 52 includes compression spring 40 in recess 38 coupled to valve stem 30 by D-ring 36.",
"Spring 40 is placed under tension so as to keep valve head 34 and O-ring 32 tightly closed against the shoulders of vent chamber 26.",
"Vent chamber 26 communicates with vent passage 31 to spout 15.",
"Operating handle 46 is attached to body 11 and disposed in a slot 13 in body 11.",
"Handle 46 is pivoted by pivot 48 and contacts the end of valve stem 30 in cutout 51.",
"Slot 13 is formed so as to act as a stop for handle 46 in the position shown.",
"Handle 64 includes a thumb tab portion 58 and body 11 includes a finger grip portion 12.",
"The user may thus grasp handle 46 and body 11 with the thumb and fingers, causing handle lever 50 to move forward as indicated by arrow D moving valve stem 30 in the direction as shown by arrow E thereby opening vent chamber 26 to vent passage 31.",
"As indicated by the dashed lines, handle lever 50 will move until it contacts the bottom of slot 13.",
"Although not shown in FIG. 4, chambers 26 and 37 are arranged side by side horizontally as best seen in FIGS. 5 and 6.",
"As noted in the cross-sectional view of body 11 of FIG. 6 through a horizontal plane, fluid chamber 37 is essentially parallel to chamber 26 and communicates with fluid passage 33 parallel to vent passage 31 which also connects to spout 15.",
"As may be noted from FIG. 6, spout 15 as shown in the dashed lines is elliptical in shape while passages 31 and 33 are circular.",
"In FIG. 6, ullage vent tube 8 is shown installed in bore 24 and communicates with chamber 26.",
"Details of the vent valve element 52 and fluid valve element 42 are shown in FIG. 7. Valve 52 includes a tapered head assembly 34 with O-ring 32 disposed in a groove therein.",
"A groove 39 is provided at the other end of valve stem 30 for accepting a spring retaining D-washer as shown in FIG. 4. As previously shown, valve head 34 is installed in vent chamber 26.",
"Tapered head 34 of valve 52 permits the user to control the flow of gas under pressure in ullage volume 7 by the degree of pressure on valve stem 30.",
"Fluid valve element 42 is seen to be slightly shorter than vent valve element 52 and includes a head portion 45 having an O-ring 43 disposed thereon, a stem 42 and a groove 45 for accepting a D-washer for retaining spring 41.",
"Head 41 is installed in fluid chamber 37 with stem 47 parallel with vent valve stem 30.",
"Lever portion 50 of handle 46 is sufficiently wide so as to contact both valve stem 30 and valve stem 47 when handle 46 is moved in the direction shown by arrow D in FIG. 4. Since stem 47 is slightly shorter than stem 40, it will be understood that lever portion 50 will open vent valve 52 before contacting the end of liquid valve stem 47.",
"Thus, venting or escape of pressurized gas occurs before opening of the fluid valve 42.",
"When handle 46 is FIG. 4 is fully depressed and in the position indicated by the dashed lines, both valves will be opened and the fluid in the attached container will flow through fluid passage 33 and spout 15 to a glass or other container.",
"Handle 46 may be temporarily locked in the unoperated position by means of a locking arm 56 pivotally attached to handle 46.",
"Arm 56 is shown in the retracted position in FIG. 4. When extended, as indicated by the dashed lines, arm 56 contacts a concave area 57 of body 11 thereby preventing handle 46 from being depressed.",
"After use of the dispensing valve assembly 10, the container with the assembly in place is removed from the stand 60 and stored with the dispensing valve assembly 10 remaining on the neck of the container, ready for subsequent use.",
"The tightly closed valves and the cap thread O-ring prevents any loss of carbonation by leakage around a cap.",
"Although I have disclosed a preferred stand 60 for holding the container and dispensing valve assembly of my invention in FIG. 2, an alternative design for a stand is shown in FIG. 8. Stand 70 may be noted to have the supporting sides thereof oppositely disposed from those of the stand of FIG. 2. The angle of the front portion of the stand 70 with the vertical shown as in FIG. 3 may be varied as desired to form a more compact arrangement which can be installed within a refrigerator yet would not require excessive space.",
"In such instance, a beverage may be dispensed by simply opening a refrigerator door and filling a glass or other container without removing the beverage container and stand from the refrigerator.",
"Although I have shown specific embodiments of my invention for illustrative purposes, I consider that various changes can be made therein by those of skill in the art without departing from the spirit and scope of my invention."
] |
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/574,445 filed May 26, 2004.
FIELD OF THE INVENTION
[0002] The present invention is directed to a method of machining gears, particularly grinding of spur and helical gears, to enhance operating characteristics, such as the reduction of mesh noise.
BACKGROUND OF THE INVENTION
[0003] The reduction of mesh noise is an ongoing objective in the manufacture of gears of all types (e.g. spur, helical, bevel, hypoid, crown). It has been proposed to reduce the noise of gears running in mesh by including a honing process subsequent to heat treating as disclosed in U.S. Pat. No. 2,942,389 to Praeg et al. A further polishing step subsequent to honing for enhancing the surface finish is discussed in U.S. Pat. No. 3,909,990 to Tersch.
[0004] Finishing each member of a gear pair with a different finishing process to reduce gear noise is disclosed by U.S. Pat. No. 6,481,307 to Klingelnberg wherein one member is finished by honing and the other member is finished by grinding in an effort to create scratch-like machining marks or microstriations having different orientations on the tooth surfaces of respective gear pair members. German Patent No. DE 3826029 similarly discloses the avoidance of identical surface structures in an effort to reduce mesh noise by grinding one member of a gear pair and skiving the other member.
SUMMARY OF THE INVENTION
[0005] The present invention is directed to a method of machining gears or other toothed articles wherein the workpiece feed rate and/or the tool shifting is varied so as to produce an irregular surface pattern on tooth surfaces with a resulting reduction in mesh noise.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 schematically illustrates one type of grinding machine on which the inventive method may be carried out.
[0007] FIG. 2 is a graphical representation of a variable feed rate.
[0008] FIG. 3 shows a stroke length divided into a plurality of segments.
[0009] FIG. 4 illustrates an example of providing a different feed rate in successive segments of the grinding stroke length shown in FIG. 3 .
[0010] FIG. 5 illustrates varying the feed rate in each segment of FIG. 3 wherein the varying is described by a sine wave.
[0011] FIG. 6 illustrates varying the feed rate in each segment of FIG. 3 wherein the varying is described by a ramped function.
[0012] FIG. 7 illustrates varying the feed rate in each segment of FIG. 3 wherein the varying is described by a step function.
[0013] FIG. 8 illustrates varying the feed rate in each segment of FIG. 3 wherein the varying is described by a different function in each segment.
[0014] FIG. 9 shows a graphical representation of a variable shift rate.
[0015] FIG. 10 illustrates an example of varying the shift rate in each segment of a grinding wheel shifting region.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] The present invention will now be discussed with reference to preferred embodiments which represent the invention by way of example only. The inventive process will be discussed in light of the preferred embodiment of grinding spur and helical gears with a grinding worm, although other machining methods may be utilized and other types of types of gears may be processed in accordance with the described aspects of the invention.
[0017] The process of machining gears, in particular grinding, has a tendency to produce a microscopic precise regular surface pattern on the gear tooth flanks, generally in the lengthwise direction, that under certain operating conditions is believed to be the cause of noise when such gears are run in mesh. The inventive method may be carried out on any machine capable of controlling the relative feeding of a tool (e.g. a threaded grinding wheel also known as a grinding worm) across the tooth surface of a workpiece and/or the relative shifting of a workpiece along the grinding wheel. Machines of this type are commercially available from The Gleason Works, Rochester, N.Y. as well as other suppliers. A machine of this type is illustrated in FIG. 1 .
[0018] FIG. 1 represents a machine for grinding spur and helical gears and comprises a bed 1 on which a radial slide 2 displaceable in direction X and a tangential slide 3 displaceable in direction Y are arranged.
[0019] An axial slide 4 is displaceable in direction Z. The axial slide 4 is connected by its linear guides with a swivel slide 5 . The axial slide 4 can be swiveled in direction A with the help of this swivel slide and can, because the swivel slide 5 is connected with the tangential slide 3 , be displaced in direction Y.
[0020] The workpiece spindle 6 and its drive are housed inside of the axial slide 4 . Workpiece spindle 6 holds a workpiece (not illustrated).
[0021] The radial slide 2 carries the tool spindle (not illustrated), the tool 7 embodied as a cylindrical grinding worm, and the tool drive 8 . Radial slide 2 further carries the base for receiving a conventional dressing device. Such a dressing device is comprised, for example, of one or more diamond-coated dressings discs (not illustrated) with bearings and drives. Advantageously, the axis of the dressing disc(s) runs parallel to the rotational axis of the grinding worm 7 .
[0022] The dressing device is displaceable in direction U (parallel to X) by a U slide 9 and in direction V (parallel to Y) by a V slide 10 .
[0023] The machine of FIG. 1 includes a computer control system which governs the operation of the above components in accordance with instructions input to the machine controller, for example a computer numerical control (CNC) system such as the Fanuc model 160i-B or Siemens model 840D (not shown).
[0024] FIG. 2 illustrates an embodiment of the present invention wherein the feed rate of the grinding wheel relative to the workpiece (feed direction along the Z-axis in FIG. 1 ) is varied along the stroke length of the grinding wheel as it passes along the face width of the tooth surface. FIG. 2 illustrates a sinusoidal depiction of a feed rate along the stroke length wherein it can be seen that in comparison to a normal (constant) feed rate (horizontal line) for a given gear, the varied feed rate first increases at varying amounts and then decreases at varying amounts. The amplitude and frequency of the sine wave may vary along the stroke length. A single wave is shown in FIG. 2 . The effect of such a feed rate is that the spacing of grinding micro scratches will be irregular along the face width of the tooth surface. It should be understood that the feed rate is not to be limited to being described by a sinusoidal wave but may be described by any line that varies in orientation along the stroke length with respect to the horizontal Normal Feed Rate line shown in FIG. 2 .
[0025] Another embodiment of the present invention comprises dividing the stroke length of the grinding wheel relative to the face width into a predetermined number of segments (1 to n) and adjusting or varying the feed rate (FR) in each segment. For example, in FIG. 3 , the stroke length has been divided into six segments (FR 1 -FR 6 ). FIG. 4 illustrates a process wherein the feed rate in each segment (FR 1 -FR 6 ) is varied by an amount different from that of the previous segment. For example, the feed rate of segment FR 1 may be +5% with respect to a normal constant feed rate FR c for the particular job. The feed rate in segment FR 2 may be adjusted to −5% of FR c . The pattern may be repeated for the remaining segments. However, the adjusted feed rate need not follow a regular pattern of change. Instead, the feed rate may be increased or decreased from one segment to another by any percentage.
[0026] A more preferred embodiment is shown in FIG. 5 wherein the feed rate in each segment FR is described by a sine wave. Although sine waves having constant amplitudes are shown (e.g. ±5% with respect to FR c in each segment), the amplitudes of the sine wave in each segment need not be equal. As with the above discussion with respect to the entire tooth face width ( FIG. 2 ), the feed rate in each segment is not to be limited to being described by a sinusoidal wave but may be described by any line that varies in orientation along the stroke length in each segment with respect to the horizontal Normal Feed Rate line FR c .
[0027] FIGS. 6, 7 and 8 illustrate additional examples of varying feed rates within each segment. FIG. 6 shows a feed rate within each segment described by a ramped function with a maximum/minimum of, for example, ±5% with respect to FR c in each segment. FIG. 7 illustrates a feed rate within each segment described by a step function (e.g. ±5% with respect to FR c in each segment) and FIG. 8 describes a process wherein a different type of varying feed rate is applied in each segment. In the illustrated example of FIG. 8 , a step function, sine wave and ramped function are applied to respective successive segments and the pattern is repeated for additional segments. Also, a varied feed rate described by, for example, one or more of a step function, sine wave and ramped function may be applied across the entire tooth surface width as a whole, i.e. no segments are utilized.
[0028] The present invention also contemplates varying the shift rate of the grinding wheel (shift direction along the Y-axis in FIG. 1 ) relative to the workpiece during grinding of a workpiece. Shifting is utilized in order to expose a workpiece to new or lesser used portions of a grinding wheel thereby enabling higher metal removal rates that, consequently, allow for faster machine cycle times. During shifting, the rate of shifting can be adjusted in accordance with those changes discussed above with respect to varying the feed rate. FIG. 9 illustrates a sinusoidal depiction of a shift rate along a wheel shift portion wherein it can be seen that in comparison to a normal (constant) shift rate (horizontal line), the varied shift rate first increases at varying amounts and then decreases at varying amounts. The amplitude and frequency of the sine wave may vary along a designated wheel shift portion. A single wave is shown in FIG. 9 . As described above, the effect of such a shift rate is that the spacing of grinding micro scratches will be irregular along the face width of the tooth surface. Again, it should be understood that the shift rate is not to be limited to being described by a sinusoidal wave but may be described by any line that varies in orientation along the total amount of shift with respect to the horizontal Normal Shift Rate line shown in FIG. 9 .
[0029] Further embodiments of the present invention comprises dividing a shift portion length of the grinding wheel into a predetermined number of segments (1 to n) and adjusting or varying the shift rate (SR) in each segment. FIG. 10 shows a grinding wheel W wherein portions P 1 , P 2 and P 3 have been identified as illustrating shifting regions of the grinding wheel. A shifting region is a portion of the wheel width along which shifting occurs while a workpiece is being ground. The shift rate within each portion may be varied. Looking at the exploded view of wheel portion P 1 it can be seen that P 1 has been divided into four segments (although any number of segments, 1 to n, are contemplated) and the shift rate within each segment (SR 1 -SR 4 ) may be varied.
[0030] In a like manner with respect to FIGS. 4-8 , the varied shift rate within particular segments may also be described by any line that varies in orientation along the length of the shift portion with respect to the horizontal Shift Rate line, SR c , shown in FIG. 9 or 10 . Preferably, for example, the shift rate may be described by a sine wave as illustrated in FIG. 10 . Alternatively, the shift rate may be varied by an amount different from that of the previous segment. For example, the shift rate of segment SR 1 may be +5% with respect to a normal constant shift rate SR c for the particular gear. The shift rate in segment FR 2 may be adjusted to −5% of SR c . The pattern may be repeated, if desired, for the remaining segments although no specific pattern need be followed. The shift rate may also be described by a ramped function or a step function. A combination of the above may also be utilized wherein a different type of varying feed rate is applied in each segment. Also, a varied shift rate described by, for example, one or more of a step function, sine wave and ramped function may be applied across the entire tooth surface width as a whole, i.e. no segments are utilized.
[0031] It should be understood that varying the feed rate and varying the shift rate may be utilize separately and in combination with one another. Also, for example, a varying feed rate may be described in a sinusoidal manner while a varying shift rate may be described by a varying percentage of a constant shift rate. The opposite is also contemplated. It is further intended that regardless of the manner by which varying occurs, the amount of time required to perform a machining process will not exceed that amount of time necessary to machine by the known constant feed rate and/or shift rate processes.
[0032] Although the present invention has been discussed with reference to the preferred embodiment of grinding spur and helical gears with a grinding worm, the invention is not limited thereto. The inventive method is applicable to other finishing processes for spur and helical gears such as hobbing (either pre-heat treatment or post-heat treatment) as well as hard skiving which utilizes a hob-type tool. The method of varying the feed rate is also applicable to grinding bevel, hypoid and crown gears such as by grinding with a flared-cup type grinding wheel or by a generated method utilizing a cup-shaped grinding wheel.
[0033] While the invention has been described with reference to preferred embodiments it is to be understood that the invention is not limited to the particulars thereof. The present invention is intended to include modifications which would be apparent to those skilled in the art to which the subject matter pertains without deviating from the spirit and scope of the appended claims. | A method of machining gears or other toothed articles wherein the workpiece feed rate and/or the tool shifting is varied so as to produce an irregular surface pattern on tooth surfaces with a resulting reduction in mesh noise. The method is particularly applicable to grinding spur and/or helical gears with a grinding worm. | Briefly outline the background technology and the problem the invention aims to solve. | [
"[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/574,445 filed May 26, 2004.",
"FIELD OF THE INVENTION [0002] The present invention is directed to a method of machining gears, particularly grinding of spur and helical gears, to enhance operating characteristics, such as the reduction of mesh noise.",
"BACKGROUND OF THE INVENTION [0003] The reduction of mesh noise is an ongoing objective in the manufacture of gears of all types (e.g. spur, helical, bevel, hypoid, crown).",
"It has been proposed to reduce the noise of gears running in mesh by including a honing process subsequent to heat treating as disclosed in U.S. Pat. No. 2,942,389 to Praeg et al.",
"A further polishing step subsequent to honing for enhancing the surface finish is discussed in U.S. Pat. No. 3,909,990 to Tersch.",
"[0004] Finishing each member of a gear pair with a different finishing process to reduce gear noise is disclosed by U.S. Pat. No. 6,481,307 to Klingelnberg wherein one member is finished by honing and the other member is finished by grinding in an effort to create scratch-like machining marks or microstriations having different orientations on the tooth surfaces of respective gear pair members.",
"German Patent No. DE 3826029 similarly discloses the avoidance of identical surface structures in an effort to reduce mesh noise by grinding one member of a gear pair and skiving the other member.",
"SUMMARY OF THE INVENTION [0005] The present invention is directed to a method of machining gears or other toothed articles wherein the workpiece feed rate and/or the tool shifting is varied so as to produce an irregular surface pattern on tooth surfaces with a resulting reduction in mesh noise.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0006] FIG. 1 schematically illustrates one type of grinding machine on which the inventive method may be carried out.",
"[0007] FIG. 2 is a graphical representation of a variable feed rate.",
"[0008] FIG. 3 shows a stroke length divided into a plurality of segments.",
"[0009] FIG. 4 illustrates an example of providing a different feed rate in successive segments of the grinding stroke length shown in FIG. 3 .",
"[0010] FIG. 5 illustrates varying the feed rate in each segment of FIG. 3 wherein the varying is described by a sine wave.",
"[0011] FIG. 6 illustrates varying the feed rate in each segment of FIG. 3 wherein the varying is described by a ramped function.",
"[0012] FIG. 7 illustrates varying the feed rate in each segment of FIG. 3 wherein the varying is described by a step function.",
"[0013] FIG. 8 illustrates varying the feed rate in each segment of FIG. 3 wherein the varying is described by a different function in each segment.",
"[0014] FIG. 9 shows a graphical representation of a variable shift rate.",
"[0015] FIG. 10 illustrates an example of varying the shift rate in each segment of a grinding wheel shifting region.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0016] The present invention will now be discussed with reference to preferred embodiments which represent the invention by way of example only.",
"The inventive process will be discussed in light of the preferred embodiment of grinding spur and helical gears with a grinding worm, although other machining methods may be utilized and other types of types of gears may be processed in accordance with the described aspects of the invention.",
"[0017] The process of machining gears, in particular grinding, has a tendency to produce a microscopic precise regular surface pattern on the gear tooth flanks, generally in the lengthwise direction, that under certain operating conditions is believed to be the cause of noise when such gears are run in mesh.",
"The inventive method may be carried out on any machine capable of controlling the relative feeding of a tool (e.g. a threaded grinding wheel also known as a grinding worm) across the tooth surface of a workpiece and/or the relative shifting of a workpiece along the grinding wheel.",
"Machines of this type are commercially available from The Gleason Works, Rochester, N.Y. as well as other suppliers.",
"A machine of this type is illustrated in FIG. 1 .",
"[0018] FIG. 1 represents a machine for grinding spur and helical gears and comprises a bed 1 on which a radial slide 2 displaceable in direction X and a tangential slide 3 displaceable in direction Y are arranged.",
"[0019] An axial slide 4 is displaceable in direction Z. The axial slide 4 is connected by its linear guides with a swivel slide 5 .",
"The axial slide 4 can be swiveled in direction A with the help of this swivel slide and can, because the swivel slide 5 is connected with the tangential slide 3 , be displaced in direction Y. [0020] The workpiece spindle 6 and its drive are housed inside of the axial slide 4 .",
"Workpiece spindle 6 holds a workpiece (not illustrated).",
"[0021] The radial slide 2 carries the tool spindle (not illustrated), the tool 7 embodied as a cylindrical grinding worm, and the tool drive 8 .",
"Radial slide 2 further carries the base for receiving a conventional dressing device.",
"Such a dressing device is comprised, for example, of one or more diamond-coated dressings discs (not illustrated) with bearings and drives.",
"Advantageously, the axis of the dressing disc(s) runs parallel to the rotational axis of the grinding worm 7 .",
"[0022] The dressing device is displaceable in direction U (parallel to X) by a U slide 9 and in direction V (parallel to Y) by a V slide 10 .",
"[0023] The machine of FIG. 1 includes a computer control system which governs the operation of the above components in accordance with instructions input to the machine controller, for example a computer numerical control (CNC) system such as the Fanuc model 160i-B or Siemens model 840D (not shown).",
"[0024] FIG. 2 illustrates an embodiment of the present invention wherein the feed rate of the grinding wheel relative to the workpiece (feed direction along the Z-axis in FIG. 1 ) is varied along the stroke length of the grinding wheel as it passes along the face width of the tooth surface.",
"FIG. 2 illustrates a sinusoidal depiction of a feed rate along the stroke length wherein it can be seen that in comparison to a normal (constant) feed rate (horizontal line) for a given gear, the varied feed rate first increases at varying amounts and then decreases at varying amounts.",
"The amplitude and frequency of the sine wave may vary along the stroke length.",
"A single wave is shown in FIG. 2 .",
"The effect of such a feed rate is that the spacing of grinding micro scratches will be irregular along the face width of the tooth surface.",
"It should be understood that the feed rate is not to be limited to being described by a sinusoidal wave but may be described by any line that varies in orientation along the stroke length with respect to the horizontal Normal Feed Rate line shown in FIG. 2 .",
"[0025] Another embodiment of the present invention comprises dividing the stroke length of the grinding wheel relative to the face width into a predetermined number of segments (1 to n) and adjusting or varying the feed rate (FR) in each segment.",
"For example, in FIG. 3 , the stroke length has been divided into six segments (FR 1 -FR 6 ).",
"FIG. 4 illustrates a process wherein the feed rate in each segment (FR 1 -FR 6 ) is varied by an amount different from that of the previous segment.",
"For example, the feed rate of segment FR 1 may be +5% with respect to a normal constant feed rate FR c for the particular job.",
"The feed rate in segment FR 2 may be adjusted to −5% of FR c .",
"The pattern may be repeated for the remaining segments.",
"However, the adjusted feed rate need not follow a regular pattern of change.",
"Instead, the feed rate may be increased or decreased from one segment to another by any percentage.",
"[0026] A more preferred embodiment is shown in FIG. 5 wherein the feed rate in each segment FR is described by a sine wave.",
"Although sine waves having constant amplitudes are shown (e.g. ±5% with respect to FR c in each segment), the amplitudes of the sine wave in each segment need not be equal.",
"As with the above discussion with respect to the entire tooth face width ( FIG. 2 ), the feed rate in each segment is not to be limited to being described by a sinusoidal wave but may be described by any line that varies in orientation along the stroke length in each segment with respect to the horizontal Normal Feed Rate line FR c .",
"[0027] FIGS. 6, 7 and 8 illustrate additional examples of varying feed rates within each segment.",
"FIG. 6 shows a feed rate within each segment described by a ramped function with a maximum/minimum of, for example, ±5% with respect to FR c in each segment.",
"FIG. 7 illustrates a feed rate within each segment described by a step function (e.g. ±5% with respect to FR c in each segment) and FIG. 8 describes a process wherein a different type of varying feed rate is applied in each segment.",
"In the illustrated example of FIG. 8 , a step function, sine wave and ramped function are applied to respective successive segments and the pattern is repeated for additional segments.",
"Also, a varied feed rate described by, for example, one or more of a step function, sine wave and ramped function may be applied across the entire tooth surface width as a whole, i.e. no segments are utilized.",
"[0028] The present invention also contemplates varying the shift rate of the grinding wheel (shift direction along the Y-axis in FIG. 1 ) relative to the workpiece during grinding of a workpiece.",
"Shifting is utilized in order to expose a workpiece to new or lesser used portions of a grinding wheel thereby enabling higher metal removal rates that, consequently, allow for faster machine cycle times.",
"During shifting, the rate of shifting can be adjusted in accordance with those changes discussed above with respect to varying the feed rate.",
"FIG. 9 illustrates a sinusoidal depiction of a shift rate along a wheel shift portion wherein it can be seen that in comparison to a normal (constant) shift rate (horizontal line), the varied shift rate first increases at varying amounts and then decreases at varying amounts.",
"The amplitude and frequency of the sine wave may vary along a designated wheel shift portion.",
"A single wave is shown in FIG. 9 .",
"As described above, the effect of such a shift rate is that the spacing of grinding micro scratches will be irregular along the face width of the tooth surface.",
"Again, it should be understood that the shift rate is not to be limited to being described by a sinusoidal wave but may be described by any line that varies in orientation along the total amount of shift with respect to the horizontal Normal Shift Rate line shown in FIG. 9 .",
"[0029] Further embodiments of the present invention comprises dividing a shift portion length of the grinding wheel into a predetermined number of segments (1 to n) and adjusting or varying the shift rate (SR) in each segment.",
"FIG. 10 shows a grinding wheel W wherein portions P 1 , P 2 and P 3 have been identified as illustrating shifting regions of the grinding wheel.",
"A shifting region is a portion of the wheel width along which shifting occurs while a workpiece is being ground.",
"The shift rate within each portion may be varied.",
"Looking at the exploded view of wheel portion P 1 it can be seen that P 1 has been divided into four segments (although any number of segments, 1 to n, are contemplated) and the shift rate within each segment (SR 1 -SR 4 ) may be varied.",
"[0030] In a like manner with respect to FIGS. 4-8 , the varied shift rate within particular segments may also be described by any line that varies in orientation along the length of the shift portion with respect to the horizontal Shift Rate line, SR c , shown in FIG. 9 or 10 .",
"Preferably, for example, the shift rate may be described by a sine wave as illustrated in FIG. 10 .",
"Alternatively, the shift rate may be varied by an amount different from that of the previous segment.",
"For example, the shift rate of segment SR 1 may be +5% with respect to a normal constant shift rate SR c for the particular gear.",
"The shift rate in segment FR 2 may be adjusted to −5% of SR c .",
"The pattern may be repeated, if desired, for the remaining segments although no specific pattern need be followed.",
"The shift rate may also be described by a ramped function or a step function.",
"A combination of the above may also be utilized wherein a different type of varying feed rate is applied in each segment.",
"Also, a varied shift rate described by, for example, one or more of a step function, sine wave and ramped function may be applied across the entire tooth surface width as a whole, i.e. no segments are utilized.",
"[0031] It should be understood that varying the feed rate and varying the shift rate may be utilize separately and in combination with one another.",
"Also, for example, a varying feed rate may be described in a sinusoidal manner while a varying shift rate may be described by a varying percentage of a constant shift rate.",
"The opposite is also contemplated.",
"It is further intended that regardless of the manner by which varying occurs, the amount of time required to perform a machining process will not exceed that amount of time necessary to machine by the known constant feed rate and/or shift rate processes.",
"[0032] Although the present invention has been discussed with reference to the preferred embodiment of grinding spur and helical gears with a grinding worm, the invention is not limited thereto.",
"The inventive method is applicable to other finishing processes for spur and helical gears such as hobbing (either pre-heat treatment or post-heat treatment) as well as hard skiving which utilizes a hob-type tool.",
"The method of varying the feed rate is also applicable to grinding bevel, hypoid and crown gears such as by grinding with a flared-cup type grinding wheel or by a generated method utilizing a cup-shaped grinding wheel.",
"[0033] While the invention has been described with reference to preferred embodiments it is to be understood that the invention is not limited to the particulars thereof.",
"The present invention is intended to include modifications which would be apparent to those skilled in the art to which the subject matter pertains without deviating from the spirit and scope of the appended claims."
] |
[0001] The invention relates to a rib waveguide device with a mode filter section and particularly to a silicon rib waveguide device.
BACKGROUND OF THE INVENTION
[0002] Silicon rib waveguide devices may conduct light in single mode or multimode. The dimensions of the rib are important parameters determining the mode of light transmission. The vertical depth of the rib is such that the transmission is normally single moded in the vertical direction and references in this application to variation between single and multimode transmission relate to variations across the width of the rib.
[0003] When constructing waveguide devices on a single integrated silicon chip, some optically transmissive paths may be multimode across the transmission path and others may be single moded. Junctions between multimoded and single moded transmission paths may be required. Furthermore, rib waveguides may need to have straight sections or curved sections. Circuit components on the chip may themselves incorporate curved waveguides such as multiplexing and demultiplexing array waveguides and other parts of the chip may require curved waveguides in order to form compact interconnections between components on the chip. The radius of curvature that can be accepted for a curved waveguide will depend on the rib waveguide width as light losses from the waveguide will vary with radius of curvature. It has been found for example that with a 4 μm wide silicon rib waveguide the minimum radius of curvature without unacceptable losses is 20 mm. However if the waveguide has an increased width to 6 μm then the radius of curvature may be reduced to 12 mm with approximately the same light loss in passing through the curved section. In order to make compact devices it is desirable to be able to reduce the radius of curvature of curved sections but the use of greater width for the waveguides means using a waveguide width which in a straight section would be multimoded across its width. On passing around a curved waveguide any higher modes above the fundamental would suffer some loss from scattering on passing around the curve but some may remain when the curved waveguide joins a serially connected straight waveguide section.
[0004] It is an object of the present invention to provide a mode filter for use in combination with curved and straight silicon rib waveguides so that multimode propagation is filtered out by a narrower straight waveguide rib following a wider curved waveguide rib.
SUMMARY OF THE INVENTION
[0005] The invention provides a silicon rib waveguide device including a mode filter section serially connected to a curved rib waveguide section, said curved waveguide section having a first rib width large enough to support multimode transmission, said filter section having a straight waveguide section with a second rib width smaller than said first rib width and supporting only single mode transmission, said straight waveguide section having a first taper section connecting the curved waveguide section to a straight waveguide section and tapering in towards one end of said straight section, and a second taper section connected to an opposite end of the straight section and tapering outwardly from the straight section for connection to an optical transmission device having an optical path width greater than said second rib width.
[0006] The waveguide device may include a plurality of curved rib waveguides formed on a common silicon planar device, each connected to a similar respective mode filter section.
[0007] The first rib width may be at least 50% greater than said second rib width.
[0008] The straight section may have a length between the taper regions of at least 200 times the said second rib width.
[0009] The length of each taper section may be at least 80 times the said second rib width.
[0010] The second rib width may be approximately 4 μm and the second rib width approximately 6 μm.
[0011] The radius of curvature of the curved section may be less than 20 mm.
[0012] The radius of curvature of the curved section may be approximately 12 mm.
[0013] Said second taper section may be connected to a multimode interference (MMI) device.
[0014] The mode filter section may be optically connected with a multiplexer or demultiplexer device using a curved array of waveguides.
[0015] The waveguide device is preferably formed as an integrated silicon chip device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] [0016]FIG. 1 is a schematic view of an integrated silicon waveguide chip in accordance with the present invention,
[0017] [0017]FIG. 2 shows a prior art construction of the type of silicon rib waveguide used on the chip of FIG. 1,
[0018] [0018]FIG. 3 illustrates a prior art multiplexer and/or demultiplexer using an array of waveguides which may be incorporated on the chip of FIG. 1,
[0019] [0019]FIG. 4 illustrates a prior art use of a multimode interference (MMI) device which may be used on the chip of FIG. 1,
[0020] [0020]FIG. 5 is a perspective view of a mode filter which is incorporated in the device of FIG. 1,
[0021] [0021]FIG. 6 shows a transmission mode in the prior art device shown in FIG. 2, and
[0022] [0022]FIG. 7 illustrates a modified transmission mode in the output of a mode filter of the type shown in FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] [0023]FIG. 1 illustrates schematically an integrated silicon chip forming a waveguide device using silicon on insulator rib waveguides of the type illustrated in FIG. 2. Such waveguides are of a known type of ridge waveguide formed from silicon insulator. An upstanding rib 11 is formed on a silicon layer 12 . A silicon substrate 13 is covered with a silicon dioxide layer 14 immediately below the silicon layer 12 . A silicon dioxide coating 15 is formed over the upper surface of the silicon 12 and over the rib 11 . Optical signals are transmitted in a single mode through the silicon layer and each rib 30 as shown in FIG. 6. The mode pattern is illustrated at 16 and is in this example single moded in the vertical and horizontal directions.
[0024] In FIG. 1 the integrated silicon chip is indicated at 17 and has connected at its boundaries one or more input optical fibres 18 and a plurality of optical fibre outputs 19 and 20 . On the chip are integrally formed a plurality of optical circuitry components 21 and 22 which may be in the form of prior art optical components such as are shown in FIGS. 3 and 4. In multiplexing and demultiplexing optical circuitry it may be desirable to use an array of curved waveguide paths arranged in parallel with each other as shown in the prior art arrangement of FIG. 3. Such an array waveguide device 22 consists of a plurality of curved rib waveguides 23 arranged side by side with straight input ends focussed at one end 25 of an input waveguide 26 . The array has a plurality of straight output waveguides 27 focussed at 28 at one end of a plurality of output waveguides 29 . The optical circuitry 21 and 22 in FIG. 1 may include an array of the type that is shown in FIG. 3.
[0025] A multimode interference device (MMI) of the type shown in FIG. 4 and already known in the art may be included on the chip as part of the circuitry 21 or 22 in FIG. 1. As shown in FIG. 4, light which is being conducted on chip may have a field distribution of the type shown at 30 in FIG. 4 and pass through an input guide 31 to an MMI coupler 33 such that the output field of the MMI coupler has the double peaked field distribution shown at 34 . Such MMI couplers may be of use in providing input light to the input end of an array such as that shown in FIG. 3. The input to the MMI coupler should be single mode and symmetrical with respect to the body of silicon forming the coupler.
[0026] In the arrangement of FIG. 1 various circuitry of the type shown in FIGS. 3 and 4 together with a plurality of straight and curved rib waveguide sections may be formed to provide the most compact arrangement of circuitry on a single integrated silicon chip. In the example of FIG. 1 a plurality of waveguide mode filter sections are provided as indicated at 40 , 41 , 42 , 43 and 44 . Each of these consists of a straight narrow rib waveguide located between tapered sections at opposite ends flared outwardly from the narrow straight waveguide section and connected to adjacent optical paths of greater transverse width than the narrow rib waveguide and incorporating one or more curved rib waveguide sections as indicated at 45 and 46 .
[0027] In this example the curved rib waveguide 45 and mode filter 40 will be described with more detail with reference to FIGS. 1 and 5.
[0028] In this particular example the straight narrow rib waveguides have a narrow rib width such as 4 μm which supports only single mode transmission across its width. When forming a curved waveguide on such a silicon chip, losses occur in transmission around a curved section and the losses increase with smaller radius of curvature. For a 4 μm rib width the radius should not less than 2 omm. In order to produce a compact arrangement, it may be desirable to increase the rib width to 6 μm around the curve thereby enabling the radius to be reduced to 12 mm with approximately the same light loss as 20 mm radius for a 4 μm rib width. However, for a silicon rib width of 6 μm it is possible for multimode propagation to occur across the width of the rib in a straight waveguide section. Consequently the present embodiment includes a mode filter 40 following the curved waveguide section 45 . The structure of this is shown more clearly in FIG. 5. The curved section 45 has in this example a rib width W 1 of 6 μm and this is joined by an inwardly tapered section 50 to the narrow straight rib waveguide 51 of uniform width along its length. The straight region 51 is then connected by an outwardly flared tapered region 52 into the optical circuitry 21 which in this example is a planar slab of silicon forming an MMI coupler of the type shown at 33 in FIG. 4. It will be understood that in FIG. 5 the curved rib 45 , straight rib 51 and the planar slab 21 are all formed on a silicon substrate 53 so as to form upstanding regions from that planar substrate. In the particular example shown, the transverse width W 2 of the straight waveguide 51 is 4 μm. The length of the straight waveguide section 51 is shown at L 1 and this example is 1000 μm, that is at least 200 times the width W 2 of the straight rib section. The radius of curvature of the curved section 45 is less than 20 mm and in this example is approximately 12 mm. The length L 2 of the tapered section 50 is in this example 340 μm which is at least 80 times the width W 2 of the straight waveguide section. The length of the tapered section 52 is in this preferred example the same as the length of the tapered section 50 .
[0029] It will however be understood that other dimensions may be used. The angle of taper of the outer walls of the tapered sections 50 and 52 in relation to the axis of the straight rib waveguide 51 may for example be 0.17°.
[0030] In use of the device shown in FIGS. 1 and 5, light which is input from the input fibre 18 may include multimodes across the fibre and these will enter the chip waveguides and pass through the filter section 44 which will transmit only a single fundamental mode. Light which passes into the wider curved waveguide section 45 may include multimode transmission with some scattering on passing around the curved waveguide 45 . Any modes other than the fundamental which are output by the wider waveguide 45 will be filtered by the mode filter 40 such that only the single fundamental mode across the width of the waveguide is transmitted into the optical circuitry 21 . In the case of coupling the filter 40 to an MMI coupler providing the circuitry 21 of FIGS. 1 and 5, the symmetry of that single mode will be improved by the outwardly tapered section 52 . The normal single mode pattern shown in FIG. 6 is modified by the widening tapered section 52 so as to change into a pattern substantially as shown in FIG. 7 thereby giving greater symmetry both transversely and vertically on passing through the multimode interference device 21 . Such field patterns may be multimoded in depth as well as transversely on forming the output of the MMI device 21 .
[0031] It will be understood that the device of FIG. 1 may incorporate a variety of optical components interconnected by curved and straight rib waveguide sections. The width of the curved sections may be increased to allow the compact formation obtainable by using wider waveguide sections and the mode control may be effected by incorporating mode filter sections having straight rib waveguides with end tapered sections as described above.
[0032] The invention is not limited to the details of the foregoing example. | A silicon rib waveguide device includes a mode filter section serially connected to a curved rib section. The curved section has a width large enough to support multimode transmission while the filter section has a straight waveguide of smaller rib width supporting only single mode transmission. A tapered section connects the curved section to the straight section and an outwardly tapered waveguide is connected to the opposite end of the straight section. | Summarize the patent document, focusing on the invention's functionality and advantages. | [
"[0001] The invention relates to a rib waveguide device with a mode filter section and particularly to a silicon rib waveguide device.",
"BACKGROUND OF THE INVENTION [0002] Silicon rib waveguide devices may conduct light in single mode or multimode.",
"The dimensions of the rib are important parameters determining the mode of light transmission.",
"The vertical depth of the rib is such that the transmission is normally single moded in the vertical direction and references in this application to variation between single and multimode transmission relate to variations across the width of the rib.",
"[0003] When constructing waveguide devices on a single integrated silicon chip, some optically transmissive paths may be multimode across the transmission path and others may be single moded.",
"Junctions between multimoded and single moded transmission paths may be required.",
"Furthermore, rib waveguides may need to have straight sections or curved sections.",
"Circuit components on the chip may themselves incorporate curved waveguides such as multiplexing and demultiplexing array waveguides and other parts of the chip may require curved waveguides in order to form compact interconnections between components on the chip.",
"The radius of curvature that can be accepted for a curved waveguide will depend on the rib waveguide width as light losses from the waveguide will vary with radius of curvature.",
"It has been found for example that with a 4 μm wide silicon rib waveguide the minimum radius of curvature without unacceptable losses is 20 mm.",
"However if the waveguide has an increased width to 6 μm then the radius of curvature may be reduced to 12 mm with approximately the same light loss in passing through the curved section.",
"In order to make compact devices it is desirable to be able to reduce the radius of curvature of curved sections but the use of greater width for the waveguides means using a waveguide width which in a straight section would be multimoded across its width.",
"On passing around a curved waveguide any higher modes above the fundamental would suffer some loss from scattering on passing around the curve but some may remain when the curved waveguide joins a serially connected straight waveguide section.",
"[0004] It is an object of the present invention to provide a mode filter for use in combination with curved and straight silicon rib waveguides so that multimode propagation is filtered out by a narrower straight waveguide rib following a wider curved waveguide rib.",
"SUMMARY OF THE INVENTION [0005] The invention provides a silicon rib waveguide device including a mode filter section serially connected to a curved rib waveguide section, said curved waveguide section having a first rib width large enough to support multimode transmission, said filter section having a straight waveguide section with a second rib width smaller than said first rib width and supporting only single mode transmission, said straight waveguide section having a first taper section connecting the curved waveguide section to a straight waveguide section and tapering in towards one end of said straight section, and a second taper section connected to an opposite end of the straight section and tapering outwardly from the straight section for connection to an optical transmission device having an optical path width greater than said second rib width.",
"[0006] The waveguide device may include a plurality of curved rib waveguides formed on a common silicon planar device, each connected to a similar respective mode filter section.",
"[0007] The first rib width may be at least 50% greater than said second rib width.",
"[0008] The straight section may have a length between the taper regions of at least 200 times the said second rib width.",
"[0009] The length of each taper section may be at least 80 times the said second rib width.",
"[0010] The second rib width may be approximately 4 μm and the second rib width approximately 6 μm.",
"[0011] The radius of curvature of the curved section may be less than 20 mm.",
"[0012] The radius of curvature of the curved section may be approximately 12 mm.",
"[0013] Said second taper section may be connected to a multimode interference (MMI) device.",
"[0014] The mode filter section may be optically connected with a multiplexer or demultiplexer device using a curved array of waveguides.",
"[0015] The waveguide device is preferably formed as an integrated silicon chip device.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0016] [0016 ]FIG. 1 is a schematic view of an integrated silicon waveguide chip in accordance with the present invention, [0017] [0017 ]FIG. 2 shows a prior art construction of the type of silicon rib waveguide used on the chip of FIG. 1, [0018] [0018 ]FIG. 3 illustrates a prior art multiplexer and/or demultiplexer using an array of waveguides which may be incorporated on the chip of FIG. 1, [0019] [0019 ]FIG. 4 illustrates a prior art use of a multimode interference (MMI) device which may be used on the chip of FIG. 1, [0020] [0020 ]FIG. 5 is a perspective view of a mode filter which is incorporated in the device of FIG. 1, [0021] [0021 ]FIG. 6 shows a transmission mode in the prior art device shown in FIG. 2, and [0022] [0022 ]FIG. 7 illustrates a modified transmission mode in the output of a mode filter of the type shown in FIG. 5. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0023] [0023 ]FIG. 1 illustrates schematically an integrated silicon chip forming a waveguide device using silicon on insulator rib waveguides of the type illustrated in FIG. 2. Such waveguides are of a known type of ridge waveguide formed from silicon insulator.",
"An upstanding rib 11 is formed on a silicon layer 12 .",
"A silicon substrate 13 is covered with a silicon dioxide layer 14 immediately below the silicon layer 12 .",
"A silicon dioxide coating 15 is formed over the upper surface of the silicon 12 and over the rib 11 .",
"Optical signals are transmitted in a single mode through the silicon layer and each rib 30 as shown in FIG. 6. The mode pattern is illustrated at 16 and is in this example single moded in the vertical and horizontal directions.",
"[0024] In FIG. 1 the integrated silicon chip is indicated at 17 and has connected at its boundaries one or more input optical fibres 18 and a plurality of optical fibre outputs 19 and 20 .",
"On the chip are integrally formed a plurality of optical circuitry components 21 and 22 which may be in the form of prior art optical components such as are shown in FIGS. 3 and 4.",
"In multiplexing and demultiplexing optical circuitry it may be desirable to use an array of curved waveguide paths arranged in parallel with each other as shown in the prior art arrangement of FIG. 3. Such an array waveguide device 22 consists of a plurality of curved rib waveguides 23 arranged side by side with straight input ends focussed at one end 25 of an input waveguide 26 .",
"The array has a plurality of straight output waveguides 27 focussed at 28 at one end of a plurality of output waveguides 29 .",
"The optical circuitry 21 and 22 in FIG. 1 may include an array of the type that is shown in FIG. 3. [0025] A multimode interference device (MMI) of the type shown in FIG. 4 and already known in the art may be included on the chip as part of the circuitry 21 or 22 in FIG. 1. As shown in FIG. 4, light which is being conducted on chip may have a field distribution of the type shown at 30 in FIG. 4 and pass through an input guide 31 to an MMI coupler 33 such that the output field of the MMI coupler has the double peaked field distribution shown at 34 .",
"Such MMI couplers may be of use in providing input light to the input end of an array such as that shown in FIG. 3. The input to the MMI coupler should be single mode and symmetrical with respect to the body of silicon forming the coupler.",
"[0026] In the arrangement of FIG. 1 various circuitry of the type shown in FIGS. 3 and 4 together with a plurality of straight and curved rib waveguide sections may be formed to provide the most compact arrangement of circuitry on a single integrated silicon chip.",
"In the example of FIG. 1 a plurality of waveguide mode filter sections are provided as indicated at 40 , 41 , 42 , 43 and 44 .",
"Each of these consists of a straight narrow rib waveguide located between tapered sections at opposite ends flared outwardly from the narrow straight waveguide section and connected to adjacent optical paths of greater transverse width than the narrow rib waveguide and incorporating one or more curved rib waveguide sections as indicated at 45 and 46 .",
"[0027] In this example the curved rib waveguide 45 and mode filter 40 will be described with more detail with reference to FIGS. 1 and 5.",
"[0028] In this particular example the straight narrow rib waveguides have a narrow rib width such as 4 μm which supports only single mode transmission across its width.",
"When forming a curved waveguide on such a silicon chip, losses occur in transmission around a curved section and the losses increase with smaller radius of curvature.",
"For a 4 μm rib width the radius should not less than 2 omm.",
"In order to produce a compact arrangement, it may be desirable to increase the rib width to 6 μm around the curve thereby enabling the radius to be reduced to 12 mm with approximately the same light loss as 20 mm radius for a 4 μm rib width.",
"However, for a silicon rib width of 6 μm it is possible for multimode propagation to occur across the width of the rib in a straight waveguide section.",
"Consequently the present embodiment includes a mode filter 40 following the curved waveguide section 45 .",
"The structure of this is shown more clearly in FIG. 5. The curved section 45 has in this example a rib width W 1 of 6 μm and this is joined by an inwardly tapered section 50 to the narrow straight rib waveguide 51 of uniform width along its length.",
"The straight region 51 is then connected by an outwardly flared tapered region 52 into the optical circuitry 21 which in this example is a planar slab of silicon forming an MMI coupler of the type shown at 33 in FIG. 4. It will be understood that in FIG. 5 the curved rib 45 , straight rib 51 and the planar slab 21 are all formed on a silicon substrate 53 so as to form upstanding regions from that planar substrate.",
"In the particular example shown, the transverse width W 2 of the straight waveguide 51 is 4 μm.",
"The length of the straight waveguide section 51 is shown at L 1 and this example is 1000 μm, that is at least 200 times the width W 2 of the straight rib section.",
"The radius of curvature of the curved section 45 is less than 20 mm and in this example is approximately 12 mm.",
"The length L 2 of the tapered section 50 is in this example 340 μm which is at least 80 times the width W 2 of the straight waveguide section.",
"The length of the tapered section 52 is in this preferred example the same as the length of the tapered section 50 .",
"[0029] It will however be understood that other dimensions may be used.",
"The angle of taper of the outer walls of the tapered sections 50 and 52 in relation to the axis of the straight rib waveguide 51 may for example be 0.17°.",
"[0030] In use of the device shown in FIGS. 1 and 5, light which is input from the input fibre 18 may include multimodes across the fibre and these will enter the chip waveguides and pass through the filter section 44 which will transmit only a single fundamental mode.",
"Light which passes into the wider curved waveguide section 45 may include multimode transmission with some scattering on passing around the curved waveguide 45 .",
"Any modes other than the fundamental which are output by the wider waveguide 45 will be filtered by the mode filter 40 such that only the single fundamental mode across the width of the waveguide is transmitted into the optical circuitry 21 .",
"In the case of coupling the filter 40 to an MMI coupler providing the circuitry 21 of FIGS. 1 and 5, the symmetry of that single mode will be improved by the outwardly tapered section 52 .",
"The normal single mode pattern shown in FIG. 6 is modified by the widening tapered section 52 so as to change into a pattern substantially as shown in FIG. 7 thereby giving greater symmetry both transversely and vertically on passing through the multimode interference device 21 .",
"Such field patterns may be multimoded in depth as well as transversely on forming the output of the MMI device 21 .",
"[0031] It will be understood that the device of FIG. 1 may incorporate a variety of optical components interconnected by curved and straight rib waveguide sections.",
"The width of the curved sections may be increased to allow the compact formation obtainable by using wider waveguide sections and the mode control may be effected by incorporating mode filter sections having straight rib waveguides with end tapered sections as described above.",
"[0032] The invention is not limited to the details of the foregoing example."
] |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a multilayer directional coupler used in a mobile communication apparatus such as a cellular phone or the like.
[0003] 2. Description of the Related Art
[0004] Multilayer directional couplers include, for example, the technologies disclosed in Japanese Unexamined Patent Application Publication No. 05-152814 and Japanese Unexamined Patent Application Publication No. 05-160614. These directional couplers have a structure in which strip-line transmission lines, each having a length of a quarter wavelength or not greater than a quarter wavelength, are laminated and formed in a dielectric substrate. On the basis of this structure, these directional couplers can be easily mass-produced and reduced in size. Accordingly, these multilayer directional couplers are widely used in mobile communication apparatuses, etc.
[0005] However, in these directional couplers, a bandwidth at which a stable degree of electromagnetic coupling can be obtained is represented by a bandwidth ratio of 50% or less. Therefore, these multilayer directional couplers cannot be used in apparatuses that need a signal having a bandwidth ratio of 90% or greater, such as a television signal.
[0006] Conversely, a directional coupler capable of realizing a band with ratio of 99% or greater is disclosed in Michael G. Ellis, “RF Directional Couplers”, Electronic System Products, Searched on May 20, 2005, Internet, http://members.tripod.com/michaelgellis/direct.html.
[0007] As shown in FIG. 14 , this directional coupler 100 is constructed by winding an electrode 102 around a binocular-shaped magnetic core 101 , and its circuit configuration is as shown in FIG. 15 .
[0008] In this configuration, by appropriately setting a winding ratio (a ratio of the numbers of turns) N 1 of a coil 112 to coil 111 of a transformer 110 , and appropriately setting a winding ratio (a ratio of the numbers of turns) N 2 of a coil 121 to coil 122 of a transformer 120 , for example, a main signal input from a port 110 a (port 110 b ) of the transformer 110 can be output to a port 110 b (port 110 a ) and a port 120 a (port 120 b ) of the transformer 120 at a distribution ratio corresponding to the winding ratios.
[0009] However, since, as shown in FIG. 14 , for the directional coupler 100 , an operation of manually winding the electrode 102 around the magnetic core 101 is needed, mass productivity is low compared with the above multilayer directional couplers. In addition, this type of directional coupler needs at least a volume of 80 mm 3 , and is accordingly not suitable in terms of size reduction. In addition, with the directional coupler 100 , it is difficult to finely and accurately set the degree of electromagnetic coupling between the transformers because the degree of electromagnetic coupling between the transformers must be set on the basis of a winding ratio (a ratio of the numbers of turns) of the electrode 102 . Accordingly, a main signal input to the port 110 a (the port 110 b ) may not be output to the port 110 b (the port 110 a ) and the port 120 a (the port 120 b ) of the transformer 120 at a desired distribution ratio.
SUMMARY OF THE INVENTION
[0010] In order to overcome the problems described above, preferred embodiments of the present invention provide a multilayer directional coupler that is easy to mass-produce and reduce in size, in which fine setting of the degree of electromagnetic coupling is facilitated, and which has a large bandwidth ratio.
[0011] A multilayer directional coupler according to a preferred embodiment of the present invention includes a first magnetic substrate, a laminate laminated on the first magnetic substrate, first and second transformers provided in the laminate, and a second magnetic substrate provided on the laminate. Two ends of a primary coil of the first transformer defines input and output terminals for a main signal, one end of a secondary coil of the first transformer defines a ground terminal, and the other end of the secondary coil is connected to one terminal of a secondary coil of the second transformer. One end of a primary coil of the second transformer is connected to one terminal of the first transformer, the other end of the primary coil of the second transformer is connected to the ground terminal, and one terminal of the secondary coil of the second transformer is used as an output terminal for outputting a sub-signal. The winding length ratio N 1 of the secondary coil to primary coil of the first transformer and the winding length ratio N 2 of the primary coil to secondary coil of the second transformer are each preferably set to a value that is greater than 1 and not greater than 10.
[0012] The above-described configuration allows the multilayer directional coupler to have a multilayer structure including the first magnetic substrate, the laminate having the first and second transformers located therein, and the second magnetic substrate. Thus, by using a known production technology such as photolithography, micro-multilayer directional couplers can be mass-produced.
[0013] When the main signal is input to the input terminal of the primary coil of the first transformer, the main signal is distributed and output from the output terminal of the primary coil and the output terminal of the secondary coil of the second transformer. In this case, the distribution ratio is determined depending on the degree of electromagnetic coupling between the first and second transformers. The degree of electromagnetic coupling is determined on the basis of a winding length ratio N 1 of the secondary coil to first coil of the first transformer and a winding length ratio N 2 of the primary coil to secondary coil of the second transformer. Accordingly, in a preferred embodiment of the present invention, the winding length ratios N 1 and N 2 are each set to a value that is greater than about 1 and not greater than about 10.
[0014] In addition, since the first and second transformers can be formed by a known technology such as photolithography, the lengths of the coils of the first and second transformers can be pattern-formed so as to have preferable values. Accordingly, differently from the directional coupler 100 of the related art, the winding length ratios N 1 and N 2 of the first and second transformers can be finely and accurately set, thus enabling fine setting of the degree of electromagnetic coupling.
[0015] Further, the two ends of the primary coil of the first transformer define the input and output terminals for the main signal, one end of the secondary coil of the first transformer defines the ground terminal, and the other end of the secondary coil is connected to one terminal of the secondary coil of the second transformer. One end of a primary coil of the second transformer is connected to one terminal of the first transformer, the other end of the primary coil of the second transformer is connected to the ground terminal, and one terminal of the secondary coil of the second transformer defines the output terminal for outputting the sub-signal. Thus, the multilayer directional coupler can be used even for an apparatus that needs a signal having a bandwidth ratio equal to or greater than 90%, such as a television signal.
[0016] The ratio of the winding length ratio N 2 to the winding length ratio N 1 is preferably set to a value that is greater than about 0.5 and less than about 2.0.
[0017] The laminate is preferably formed by covering the first and second transformers with a non-magnetic body.
[0018] As described above in detail, preferred embodiments of the present invention provide a multilayer directional coupler which is easy to mass-produce and reduce in size, in which fine setting of the degree of electromagnetic coupling between the first and second transformers is facilitated, and which has a large bandwidth ratio.
[0019] Since the ratio of the winding length ratio N 2 to the winding length ratio N 1 is preferably set to a value that is greater than about 0.5 and less than about 2.0, an advantage is obtained in that a multilayer directional coupler in which the degree of electromagnetic coupling and directionality between the first and second transformers can be finely and accurately adjusted.
[0020] Other features, elements, processes, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is an exploded perspective view of a multilayer directional coupler according to a preferred embodiment of the present invention.
[0022] FIG. 2 is an exterior view of the multilayer directional coupler.
[0023] FIG. 3 is a plan view of a conductor pattern of a bottom layer.
[0024] FIG. 4 is a plan view of a non-magnetic layer.
[0025] FIG. 5 is a plan view of a conductor pattern of the second layer from the bottom.
[0026] FIG. 6 is an exploded perspective view showing a connection structure of the conductor pattern of the bottom layer and the conductor pattern of the second layer.
[0027] FIG. 7 is a plan view of a conductor pattern of the third layer from the bottom.
[0028] FIG. 8 is a plan view of a non-magnetic layer.
[0029] FIG. 9 is a plan view of a conductor pattern of a top layer.
[0030] FIG. 10 is an exploded perspective view showing a connection structure of the conductor pattern of the third layer and the conductor pattern of the top layer.
[0031] FIG. 11 is a schematic diagram showing an electrical structure of first and second transformers.
[0032] FIG. 12 is a graph showing a winging length ratio of coils and the degree of coupling between the first and second transformers.
[0033] FIG. 13 is a perspective view showing a mounting state of a multilayer directional coupler.
[0034] FIG. 14 is a perspective view showing an example of a directional coupler of the related art.
[0035] FIG. 15 is an equivalent circuit diagram of the directional coupler in FIG. 14 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] Preferred embodiments of the present invention are described below with reference to the drawings.
[0037] FIG. 1 is an exploded view of a multilayer directional coupler according to a preferred embodiment of the present invention. FIG. 2 is an exterior view of the multilayer directional coupler.
[0038] As shown in FIG. 2 , a multilayer directional coupler 1 according to the present preferred embodiment preferably includes a magnetic substrate 2 - 1 as a first magnetic substrate, a laminate 3 laminated on the magnetic substrate 2 - 1 , a magnetic substrate 2 - 2 bonded as a second magnetic substrate to the laminate 3 , and external electrodes 4 - 1 to 4 - 6 .
[0039] As shown in FIG. 1 , the laminate 3 includes a first transformer 5 , a second transformer 6 , and a non-magnetic body 7 (see FIG. 2 ) that externally, completely covers the first and second transformers 5 and 6 .
[0040] The non-magnetic body 7 preferably is, for example, formed of a dielectric, and formed by laminating non-magnetic layers 71 to 75 . The first and second transformers 5 and 6 are pattern-formed on the non-magnetic layers 71 to 74 .
[0041] Specifically, the first transformer 5 includes a primary coil 5 - 1 and a secondary coil 5 - 2 above it. The primary coil 5 - 1 is defined by conductor patterns 51 and 52 , and the secondary coil 5 - 2 is defined by conductor patterns 53 and 54 .
[0042] In addition, the second transformer 6 includes a primary coil 6 - 1 and a secondary coil 6 - 2 above it. The primary coil 6 - 1 is defined by conductor patterns 63 and 64 , and a secondary coil 6 - 2 is defined by conductor patterns 61 and 62 .
[0043] Here, structures of the first and second transformers 5 and 6 are specifically described.
[0044] The conductor patterns 51 and 64 are pattern-formed on the non-magnetic layer 71 laminated on the magnetic substrate 2 - 1 by a photolithography method or the like. After the non-magnetic layer 72 is laminated on the conductor patterns 51 and 64 , the conductor patterns 52 and 63 are pattern-formed on the non-magnetic layer 72 .
[0045] FIG. 3 is a plan view of the conductor patterns 51 and 64 . FIG. 4 is a plan view of the non-magnetic layer 72 . FIG. 5 is a plan view of the conductor patterns 52 and 63 . FIG. 6 is an exploded perspective view showing a connection structure of the conductor patterns 51 and 64 , and the conductor patterns 52 and 63 .
[0046] As shown in FIG. 3 , the conductor pattern 51 includes an internal electrode 51 a leading from the inside and an end portion 51 b inside the pattern. As shown in FIG. 5 , the conductor pattern 52 includes an internal electrode 52 a leading to the outside and an inside end portion 52 b.
[0047] As shown in FIG. 6 , the end portion 51 b of the conductor pattern 51 is connected to the end portion 52 b of the conductor pattern 52 by a through hole 72 b in the non-magnetic layer 72 , which is shown also in FIG. 4 . This defines the primary coil 5 - 1 , which is spiral, and which uses the internal electrodes 51 a and 52 a as two ends of the primary coil 5 - 1 .
[0048] In addition, as shown in FIG. 3 , the conductor pattern 64 includes an internal electrode 64 a leading to an outside central portion (a position corresponding to the internal electrode 52 a ) of the conductor pattern 51 , which is next to the conductor pattern 64 . Left-pointing end portions 64 b to 64 d and right-pointing end portions 64 e to 64 h are alternately arranged on a side opposite to a side on which the internal electrode 64 a leads. As shown in FIG. 5 , the conductor pattern 63 includes an internal electrode 63 a leading from the inside up to the center between the conductor patterns 52 and 63 . Pattern end portions 63 b to 63 d are arranged to the left of a lead of the internal electrode 63 a , and end portions 63 e to 63 h are arranged to the right of the lead. As shown in FIG. 6 , end portions 64 b to 64 d of the conductor pattern 64 are respectively connected to end portions 63 b to 63 d of the conductor pattern 63 by through holes 72 b ′ to 72 d ′ of the non-magnetic layer 72 , which are shown also in FIG. 4 . Also, end portions 64 e to 64 h of the conductor pattern 64 are respectively connected to end portions 63 e to 63 h of the conductor pattern 63 by through holes 72 e ′ to 72 h ′. This defines the primary coil 6 - 1 , which is spiral, and which uses the internal electrodes 64 a and 63 a as two ends of the primary coil 6 - 1 .
[0049] Two leads of the internal electrodes 52 a and 64 a are connected by a through hole 72 j in the non-magnetic layer 72 .
[0050] In addition, as shown in FIG. 1 , the conductor patterns 53 and 62 are pattern-formed on the non-magnetic layer 73 , which is laminated on the conductor patterns 52 and 63 . After the non-magnetic layer 74 is laminated on the conductor patterns 53 and 62 , the conductor patterns 54 and 61 are pattern-formed on the non-magnetic layer 74 .
[0051] FIG. 7 is a plan view of the conductor patterns 53 and 62 . FIG. 8 is a plan view of the non-magnetic layer 74 . FIG. 9 is a plan view of the conductor patterns 54 and 61 . FIG. 10 is an exploded perspective view showing a connection structure of the conductor patterns 53 and 62 , and the conductor patterns 54 and 61 .
[0052] As shown in FIG. 7 , the conductor pattern 53 includes an internal electrode 53 a leading from the inside up to the center between the conductor patterns 53 and 62 . End portions 53 b to 53 d are arranged to the right of a lead of the internal electrode 53 a , and end portions 53 e to 53 h are arranged to the left of the lead. In addition, as shown in FIG. 9 , the conductor pattern 54 includes an internal electrode 54 a leading to an outside central portion (a position corresponding to an internal electrode 62 a ) of the conductor pattern 61 , which is next to the internal electrode 54 . Right-pointing end portions 54 b to 54 d and left-pointing end portions 54 e to 54 h are alternately arranged on a side opposite to a side on which the internal electrode 54 a leads.
[0053] As shown in FIG. 10 , the end portions 53 b to 53 d of the conductor pattern 53 are respectively connected to the end portions 54 b to 54 d by through holes 74 b to 74 d in the non-magnetic layer 74 , which is shown also in FIG. 8 . Also, the end portions 53 e to 53 h of the conductor pattern 53 are respectively connected to the end portions 54 e to 54 h of the conductor pattern 54 by through holes 74 e to 74 h . This defines the secondary coil 5 - 2 , which is spiral, and which uses the internal electrodes 53 a and 54 a as two ends of the secondary coil 5 - 2 .
[0054] In addition, as shown in FIG. 7 , the conductor pattern 62 includes an internal electrode 62 a leading to the outside and an end portion 62 b that is inwardly positioned. Also, as shown in FIG. 9 , the conductor pattern 61 includes an internal electrode 61 a leading from the inside and an inward end portion 61 b . As shown in FIG. 10 , the end portion 62 b of the conductor pattern 62 is connected to the end portion 61 b of the conductor pattern 61 by a through hole 74 b ′ in the non-magnetic layer 74 , which is shown also in FIG. 8 . This defines the secondary coil 6 - 2 , which is spiral, and which uses the internal electrodes 62 a and 61 a as two ends of the secondary coil 6 - 2 .
[0055] In addition, two leads of the internal electrodes 54 a and 62 a are connected by a through hole 74 j in the non-magnetic layer 72 .
[0056] As shown in FIG. 1 , the non-magnetic layer 75 is laminated on the conductor patterns 54 and 61 , and the magnetic substrate 2 - 2 is bonded to the non-magnetic layer 75 .
[0057] External electrodes 4 - 1 to 4 - 6 are disposed outside the laminate 3 having the above-described structure.
[0058] This allows the external electrode 4 - 1 to electrically connect to both the internal electrodes 52 a and 64 a of the conductor patterns 52 and 64 , and allows the external electrode 4 - 2 to electrically connect to the internal electrode 51 a of the conductor pattern 51 . Also, the external electrode 4 - 3 electrically connects to the internal electrode 61 a of the conductor pattern 61 . The external electrode 4 - 4 electrically connects to both the internal electrodes 53 a and 63 a of the conductor patterns 53 and 63 . The external electrode 4 - 5 electrically connects to both the internal electrodes 54 a and 62 a of the conductor patterns 54 and 62 .
[0059] FIG. 11 is a schematic diagram showing an electrical structure of the first and second transformers 5 and 6 .
[0060] On the basis of the above connections between the conductor patterns and the above connections between the external electrodes 4 - 1 to 4 - 6 and the internal electrodes, the electrical structure has the circuit structure shown in FIG. 11 .
[0061] In other words, the external electrode 4 - 2 connected to the internal electrode 51 a of the primary coil 5 - 1 of the first transformer 5 can be used as an input terminal for a main signal, and the external electrode 4 - 1 connected to the internal electrode 52 a can be used as an output terminal for the main signal. The external electrode 4 - 4 connected to the internal electrode 53 a of the secondary coil 5 - 2 can be used as a ground terminal. The internal electrode 64 a of the primary coil 6 - 1 of the second transformer 6 is connected to the internal electrode 52 a of the primary coil, and the internal electrode 63 a is connected to the internal electrode 53 a of the secondary coil 5 - 2 of the first transformer 5 . The internal electrode 62 a of the secondary coil 6 - 2 is connected to the internal electrode 54 a of the secondary coil 5 - 2 of the first transformer 5 . Accordingly, the external electrode 4 - 3 connected to the internal electrode 61 a of the secondary coil 6 - 2 can be used as an output terminal for a sub-signal, and the external electrode 4 - 5 connected to both the internal electrodes 54 a and 62 a can be used as a terminating end by a terminating resistor or the like, which is not shown.
[0062] This circuit structure is preferably identical to a circuit structure of the directional coupler 100 shown in FIG. 15 . This multilayer directional coupler has a function of distributing and outputting the main signal input from the external electrode 4 - 2 to the external electrode 4 - 1 and 4 - 3 . Needless to say, when inputting the main signal from the external electrode 4 - 3 , the multilayer directional coupler has a function of distributing and outputting the input main signal to the external electrodes 4 - 5 and 4 - 2 .
[0063] As described above, the multilayer directional coupler has a function of distributing and outputting the main signal. The distribution ratios are determined according to the degree of electromagnetic coupling occurring between the first and second transformers, such as electromagnetic coupling between the primary and secondary coils 5 - 1 and 5 - 2 of the first transformer 5 , and electromagnetic coupling between the primary and secondary coils 6 - 1 and 6 - 2 of the second transformer 6 . The degree of electromagnetic coupling is dependent on the winding length ratio N 1 of the secondary coil 5 - 2 to the primary coil 5 - 1 of the first transformer 5 and the winding length ratio N 2 of the primary coil 6 - 1 to the secondary coil 6 - 2 of the second transformer 6 .
[0064] FIG. 12 is a graph showing the winding length ratios (N 1 , N 2 ) and the degree of coupling of the multilayer directional coupler. As a result of performing simulation in order to identify a range of the winding length ratios (N 1 , N 2 ) at which the first and second transformers have a good degree of coupling therebetween, the present inventors obtained the results shown in FIG. 12 . Specifically, it was discovered that, as indicated by curve S in FIG. 12 , the degree of coupling between the first and second transformers 5 and 6 had good values of approximately 2 dB to 20 dB in a range in which a winding length ratio (1N 2 ) was not less than about 1 and not greater than about 10. Accordingly, the winding length ratios N 1 and N 2 are preferably set so that 1<N 1 ≦10 and 1<N 2 ≦10.
[0065] Specifically, in this example of preferred embodiments of the present invention, the primary coil 5 - 1 , whose winding length was about “4.2 mm” was pattern-formed, and the secondary coil 5 - 2 , whose winding length was about “10.5 mm” was pattern-formed, with the winding length ratio N 1 set to about “2.5”. Also, the primary coil 6 - 1 , whose winding length was about “4.2 mm”, was pattern-formed, and the secondary coil 6 - 2 , whose winding length was about “10.5 mm”, was pattern-formed, with the winding length ratio N 2 set to about “2.5”. In addition, by setting a ratio (N 2 /N 1 ) of the winding length ratio N 2 to the winding length ratio N 1 so that 0.5<N 2 /N 1 <2.0, an impedance of each port can be improved. Accordingly, in this example of the preferred embodiments, the ratio N 2 /N 1 was set to approximately “1”.
[0066] In this example of the preferred embodiments, since the first and second transformers 5 and 6 are formed by a known laminating technology such as photolithography, the primary and secondary coils 5 - 1 and 5 - 2 of the first transformer 5 and the primary and secondary coils 6 - 1 and 6 - 2 of the second transformer 6 can be pattern-formed so as to have preferable winding lengths. Accordingly, the winding length ratios N 1 and N 2 of the first and second transformers can be finely and accurately set.
[0067] Next, the operation and advantages exhibited by the multilayer directional coupler according to the preferred embodiments are described.
[0068] As shown in FIG. 13 , the external electrodes 4 - 1 and 4 - 2 are connected to end portions of a main line 200 , with the external electrode 4 - 2 used as an input terminal for main signal S, and the external electrode 4 - 1 used as an output terminal. The external electrode 4 - 4 is set to a ground state. The external electrode 4 - 5 is grounded via a terminating resistor or the like, and the external electrode 4 - 3 is connected to a sub-line 201 and is used as an output terminal for sub-signal S 2 .
[0069] Accordingly, by transmitting main signal S through the main line 200 , main signal S is input from the external electrode 4 - 2 to the multilayer directional coupler 1 . Then, main signal S 1 is output from the external electrode 4 - 1 to the main line 200 , and sub-signal S 2 is output from the external electrode 4 - 3 to the sub-line 201 . In other words, main signal S input to the multilayer directional coupler 1 is distributed and output to the main line 200 and the sub-line 201 at an optimal distribution ratio corresponding to the winding length ratios N 1 and N 2 of the first and second transformers 5 and 6 and the ratio N 2 /N 1 .
[0070] With the first and second transformers 5 and 6 that are identical in circuit structure to the multilayer directional coupler 100 having the circuit structure in FIG. 15 , main signal S can be distributed as main signal S 1 and sub-signal S 2 in a wide band. Thus, the multilayer directional coupler 1 can be used even for an apparatus that needs a signal having a bandwidth ratio equal to or greater than 90%, such as a television signal.
[0071] The present invention is not limited to the above-described preferred embodiments and may be variously modified and altered within the sprit of the present invention.
[0072] For example, although, in the foregoing preferred embodiments, the winding length ratio N 1 (winding length ratio N 2 ) of the secondary coil 5 - 2 (the primary coil 6 - 1 ) to the primary coil 5 - 1 (the secondary coil 6 - 2 ) of the first transformer 5 (the second transformer 6 ) is preferably set to about “2.5”, each of the winding length ratios N 1 and N 2 may be a value that is greater than about 1 and not greater than about 10, and is not limited the value set in the foregoing preferred embodiments. In addition, although N 2 /N 1 is preferably set to about “1”, this ratio is not limited to this value since this ratio may be a value that is greater than about 0.5 and less than about 2.0.
[0073] While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims. | A multilayer directional coupler which is easy to mass-produce and reduce in size, in which fine setting of the degree of electromagnetic coupling is facilitated, and which has a large bandwidth ratio, includes magnetic substrates, a laminate including first and second transformers, and external electrodes. One external electrode, which is connected to two ends of a primary coil of the first transformer, defines an input end for a main signal, and another external electrode defines an output end. A further external electrode, which is connected to two ends of a secondary coil of the second transformer, defines an output end for a sub-signal. A winding length ratio N 1 of the secondary coil to primary coil of the first transformer and a winding length ratio N 2 of the primary coil to secondary coil of the second transformer are each set to a value that is greater than about 1 and not greater than about 10. A ratio of the winding length ratio N 2 to the winding length ratio N 1 is greater than about 0.5 and less than about 2.0. | Analyze the document's illustrations and descriptions to summarize the main idea's core structure and function. | [
"BACKGROUND OF THE INVENTION [0001] 1.",
"Field of the Invention [0002] The present invention relates to a multilayer directional coupler used in a mobile communication apparatus such as a cellular phone or the like.",
"[0003] 2.",
"Description of the Related Art [0004] Multilayer directional couplers include, for example, the technologies disclosed in Japanese Unexamined Patent Application Publication No. 05-152814 and Japanese Unexamined Patent Application Publication No. 05-160614.",
"These directional couplers have a structure in which strip-line transmission lines, each having a length of a quarter wavelength or not greater than a quarter wavelength, are laminated and formed in a dielectric substrate.",
"On the basis of this structure, these directional couplers can be easily mass-produced and reduced in size.",
"Accordingly, these multilayer directional couplers are widely used in mobile communication apparatuses, etc.",
"[0005] However, in these directional couplers, a bandwidth at which a stable degree of electromagnetic coupling can be obtained is represented by a bandwidth ratio of 50% or less.",
"Therefore, these multilayer directional couplers cannot be used in apparatuses that need a signal having a bandwidth ratio of 90% or greater, such as a television signal.",
"[0006] Conversely, a directional coupler capable of realizing a band with ratio of 99% or greater is disclosed in Michael G. Ellis, “RF Directional Couplers”, Electronic System Products, Searched on May 20, 2005, Internet, http://members.",
"tripod.com/michaelgellis/direct.",
"html.",
"[0007] As shown in FIG. 14 , this directional coupler 100 is constructed by winding an electrode 102 around a binocular-shaped magnetic core 101 , and its circuit configuration is as shown in FIG. 15 .",
"[0008] In this configuration, by appropriately setting a winding ratio (a ratio of the numbers of turns) N 1 of a coil 112 to coil 111 of a transformer 110 , and appropriately setting a winding ratio (a ratio of the numbers of turns) N 2 of a coil 121 to coil 122 of a transformer 120 , for example, a main signal input from a port 110 a (port 110 b ) of the transformer 110 can be output to a port 110 b (port 110 a ) and a port 120 a (port 120 b ) of the transformer 120 at a distribution ratio corresponding to the winding ratios.",
"[0009] However, since, as shown in FIG. 14 , for the directional coupler 100 , an operation of manually winding the electrode 102 around the magnetic core 101 is needed, mass productivity is low compared with the above multilayer directional couplers.",
"In addition, this type of directional coupler needs at least a volume of 80 mm 3 , and is accordingly not suitable in terms of size reduction.",
"In addition, with the directional coupler 100 , it is difficult to finely and accurately set the degree of electromagnetic coupling between the transformers because the degree of electromagnetic coupling between the transformers must be set on the basis of a winding ratio (a ratio of the numbers of turns) of the electrode 102 .",
"Accordingly, a main signal input to the port 110 a (the port 110 b ) may not be output to the port 110 b (the port 110 a ) and the port 120 a (the port 120 b ) of the transformer 120 at a desired distribution ratio.",
"SUMMARY OF THE INVENTION [0010] In order to overcome the problems described above, preferred embodiments of the present invention provide a multilayer directional coupler that is easy to mass-produce and reduce in size, in which fine setting of the degree of electromagnetic coupling is facilitated, and which has a large bandwidth ratio.",
"[0011] A multilayer directional coupler according to a preferred embodiment of the present invention includes a first magnetic substrate, a laminate laminated on the first magnetic substrate, first and second transformers provided in the laminate, and a second magnetic substrate provided on the laminate.",
"Two ends of a primary coil of the first transformer defines input and output terminals for a main signal, one end of a secondary coil of the first transformer defines a ground terminal, and the other end of the secondary coil is connected to one terminal of a secondary coil of the second transformer.",
"One end of a primary coil of the second transformer is connected to one terminal of the first transformer, the other end of the primary coil of the second transformer is connected to the ground terminal, and one terminal of the secondary coil of the second transformer is used as an output terminal for outputting a sub-signal.",
"The winding length ratio N 1 of the secondary coil to primary coil of the first transformer and the winding length ratio N 2 of the primary coil to secondary coil of the second transformer are each preferably set to a value that is greater than 1 and not greater than 10.",
"[0012] The above-described configuration allows the multilayer directional coupler to have a multilayer structure including the first magnetic substrate, the laminate having the first and second transformers located therein, and the second magnetic substrate.",
"Thus, by using a known production technology such as photolithography, micro-multilayer directional couplers can be mass-produced.",
"[0013] When the main signal is input to the input terminal of the primary coil of the first transformer, the main signal is distributed and output from the output terminal of the primary coil and the output terminal of the secondary coil of the second transformer.",
"In this case, the distribution ratio is determined depending on the degree of electromagnetic coupling between the first and second transformers.",
"The degree of electromagnetic coupling is determined on the basis of a winding length ratio N 1 of the secondary coil to first coil of the first transformer and a winding length ratio N 2 of the primary coil to secondary coil of the second transformer.",
"Accordingly, in a preferred embodiment of the present invention, the winding length ratios N 1 and N 2 are each set to a value that is greater than about 1 and not greater than about 10.",
"[0014] In addition, since the first and second transformers can be formed by a known technology such as photolithography, the lengths of the coils of the first and second transformers can be pattern-formed so as to have preferable values.",
"Accordingly, differently from the directional coupler 100 of the related art, the winding length ratios N 1 and N 2 of the first and second transformers can be finely and accurately set, thus enabling fine setting of the degree of electromagnetic coupling.",
"[0015] Further, the two ends of the primary coil of the first transformer define the input and output terminals for the main signal, one end of the secondary coil of the first transformer defines the ground terminal, and the other end of the secondary coil is connected to one terminal of the secondary coil of the second transformer.",
"One end of a primary coil of the second transformer is connected to one terminal of the first transformer, the other end of the primary coil of the second transformer is connected to the ground terminal, and one terminal of the secondary coil of the second transformer defines the output terminal for outputting the sub-signal.",
"Thus, the multilayer directional coupler can be used even for an apparatus that needs a signal having a bandwidth ratio equal to or greater than 90%, such as a television signal.",
"[0016] The ratio of the winding length ratio N 2 to the winding length ratio N 1 is preferably set to a value that is greater than about 0.5 and less than about 2.0.",
"[0017] The laminate is preferably formed by covering the first and second transformers with a non-magnetic body.",
"[0018] As described above in detail, preferred embodiments of the present invention provide a multilayer directional coupler which is easy to mass-produce and reduce in size, in which fine setting of the degree of electromagnetic coupling between the first and second transformers is facilitated, and which has a large bandwidth ratio.",
"[0019] Since the ratio of the winding length ratio N 2 to the winding length ratio N 1 is preferably set to a value that is greater than about 0.5 and less than about 2.0, an advantage is obtained in that a multilayer directional coupler in which the degree of electromagnetic coupling and directionality between the first and second transformers can be finely and accurately adjusted.",
"[0020] Other features, elements, processes, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0021] FIG. 1 is an exploded perspective view of a multilayer directional coupler according to a preferred embodiment of the present invention.",
"[0022] FIG. 2 is an exterior view of the multilayer directional coupler.",
"[0023] FIG. 3 is a plan view of a conductor pattern of a bottom layer.",
"[0024] FIG. 4 is a plan view of a non-magnetic layer.",
"[0025] FIG. 5 is a plan view of a conductor pattern of the second layer from the bottom.",
"[0026] FIG. 6 is an exploded perspective view showing a connection structure of the conductor pattern of the bottom layer and the conductor pattern of the second layer.",
"[0027] FIG. 7 is a plan view of a conductor pattern of the third layer from the bottom.",
"[0028] FIG. 8 is a plan view of a non-magnetic layer.",
"[0029] FIG. 9 is a plan view of a conductor pattern of a top layer.",
"[0030] FIG. 10 is an exploded perspective view showing a connection structure of the conductor pattern of the third layer and the conductor pattern of the top layer.",
"[0031] FIG. 11 is a schematic diagram showing an electrical structure of first and second transformers.",
"[0032] FIG. 12 is a graph showing a winging length ratio of coils and the degree of coupling between the first and second transformers.",
"[0033] FIG. 13 is a perspective view showing a mounting state of a multilayer directional coupler.",
"[0034] FIG. 14 is a perspective view showing an example of a directional coupler of the related art.",
"[0035] FIG. 15 is an equivalent circuit diagram of the directional coupler in FIG. 14 .",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0036] Preferred embodiments of the present invention are described below with reference to the drawings.",
"[0037] FIG. 1 is an exploded view of a multilayer directional coupler according to a preferred embodiment of the present invention.",
"FIG. 2 is an exterior view of the multilayer directional coupler.",
"[0038] As shown in FIG. 2 , a multilayer directional coupler 1 according to the present preferred embodiment preferably includes a magnetic substrate 2 - 1 as a first magnetic substrate, a laminate 3 laminated on the magnetic substrate 2 - 1 , a magnetic substrate 2 - 2 bonded as a second magnetic substrate to the laminate 3 , and external electrodes 4 - 1 to 4 - 6 .",
"[0039] As shown in FIG. 1 , the laminate 3 includes a first transformer 5 , a second transformer 6 , and a non-magnetic body 7 (see FIG. 2 ) that externally, completely covers the first and second transformers 5 and 6 .",
"[0040] The non-magnetic body 7 preferably is, for example, formed of a dielectric, and formed by laminating non-magnetic layers 71 to 75 .",
"The first and second transformers 5 and 6 are pattern-formed on the non-magnetic layers 71 to 74 .",
"[0041] Specifically, the first transformer 5 includes a primary coil 5 - 1 and a secondary coil 5 - 2 above it.",
"The primary coil 5 - 1 is defined by conductor patterns 51 and 52 , and the secondary coil 5 - 2 is defined by conductor patterns 53 and 54 .",
"[0042] In addition, the second transformer 6 includes a primary coil 6 - 1 and a secondary coil 6 - 2 above it.",
"The primary coil 6 - 1 is defined by conductor patterns 63 and 64 , and a secondary coil 6 - 2 is defined by conductor patterns 61 and 62 .",
"[0043] Here, structures of the first and second transformers 5 and 6 are specifically described.",
"[0044] The conductor patterns 51 and 64 are pattern-formed on the non-magnetic layer 71 laminated on the magnetic substrate 2 - 1 by a photolithography method or the like.",
"After the non-magnetic layer 72 is laminated on the conductor patterns 51 and 64 , the conductor patterns 52 and 63 are pattern-formed on the non-magnetic layer 72 .",
"[0045] FIG. 3 is a plan view of the conductor patterns 51 and 64 .",
"FIG. 4 is a plan view of the non-magnetic layer 72 .",
"FIG. 5 is a plan view of the conductor patterns 52 and 63 .",
"FIG. 6 is an exploded perspective view showing a connection structure of the conductor patterns 51 and 64 , and the conductor patterns 52 and 63 .",
"[0046] As shown in FIG. 3 , the conductor pattern 51 includes an internal electrode 51 a leading from the inside and an end portion 51 b inside the pattern.",
"As shown in FIG. 5 , the conductor pattern 52 includes an internal electrode 52 a leading to the outside and an inside end portion 52 b. [0047] As shown in FIG. 6 , the end portion 51 b of the conductor pattern 51 is connected to the end portion 52 b of the conductor pattern 52 by a through hole 72 b in the non-magnetic layer 72 , which is shown also in FIG. 4 .",
"This defines the primary coil 5 - 1 , which is spiral, and which uses the internal electrodes 51 a and 52 a as two ends of the primary coil 5 - 1 .",
"[0048] In addition, as shown in FIG. 3 , the conductor pattern 64 includes an internal electrode 64 a leading to an outside central portion (a position corresponding to the internal electrode 52 a ) of the conductor pattern 51 , which is next to the conductor pattern 64 .",
"Left-pointing end portions 64 b to 64 d and right-pointing end portions 64 e to 64 h are alternately arranged on a side opposite to a side on which the internal electrode 64 a leads.",
"As shown in FIG. 5 , the conductor pattern 63 includes an internal electrode 63 a leading from the inside up to the center between the conductor patterns 52 and 63 .",
"Pattern end portions 63 b to 63 d are arranged to the left of a lead of the internal electrode 63 a , and end portions 63 e to 63 h are arranged to the right of the lead.",
"As shown in FIG. 6 , end portions 64 b to 64 d of the conductor pattern 64 are respectively connected to end portions 63 b to 63 d of the conductor pattern 63 by through holes 72 b ′ to 72 d ′ of the non-magnetic layer 72 , which are shown also in FIG. 4 .",
"Also, end portions 64 e to 64 h of the conductor pattern 64 are respectively connected to end portions 63 e to 63 h of the conductor pattern 63 by through holes 72 e ′ to 72 h ′.",
"This defines the primary coil 6 - 1 , which is spiral, and which uses the internal electrodes 64 a and 63 a as two ends of the primary coil 6 - 1 .",
"[0049] Two leads of the internal electrodes 52 a and 64 a are connected by a through hole 72 j in the non-magnetic layer 72 .",
"[0050] In addition, as shown in FIG. 1 , the conductor patterns 53 and 62 are pattern-formed on the non-magnetic layer 73 , which is laminated on the conductor patterns 52 and 63 .",
"After the non-magnetic layer 74 is laminated on the conductor patterns 53 and 62 , the conductor patterns 54 and 61 are pattern-formed on the non-magnetic layer 74 .",
"[0051] FIG. 7 is a plan view of the conductor patterns 53 and 62 .",
"FIG. 8 is a plan view of the non-magnetic layer 74 .",
"FIG. 9 is a plan view of the conductor patterns 54 and 61 .",
"FIG. 10 is an exploded perspective view showing a connection structure of the conductor patterns 53 and 62 , and the conductor patterns 54 and 61 .",
"[0052] As shown in FIG. 7 , the conductor pattern 53 includes an internal electrode 53 a leading from the inside up to the center between the conductor patterns 53 and 62 .",
"End portions 53 b to 53 d are arranged to the right of a lead of the internal electrode 53 a , and end portions 53 e to 53 h are arranged to the left of the lead.",
"In addition, as shown in FIG. 9 , the conductor pattern 54 includes an internal electrode 54 a leading to an outside central portion (a position corresponding to an internal electrode 62 a ) of the conductor pattern 61 , which is next to the internal electrode 54 .",
"Right-pointing end portions 54 b to 54 d and left-pointing end portions 54 e to 54 h are alternately arranged on a side opposite to a side on which the internal electrode 54 a leads.",
"[0053] As shown in FIG. 10 , the end portions 53 b to 53 d of the conductor pattern 53 are respectively connected to the end portions 54 b to 54 d by through holes 74 b to 74 d in the non-magnetic layer 74 , which is shown also in FIG. 8 .",
"Also, the end portions 53 e to 53 h of the conductor pattern 53 are respectively connected to the end portions 54 e to 54 h of the conductor pattern 54 by through holes 74 e to 74 h .",
"This defines the secondary coil 5 - 2 , which is spiral, and which uses the internal electrodes 53 a and 54 a as two ends of the secondary coil 5 - 2 .",
"[0054] In addition, as shown in FIG. 7 , the conductor pattern 62 includes an internal electrode 62 a leading to the outside and an end portion 62 b that is inwardly positioned.",
"Also, as shown in FIG. 9 , the conductor pattern 61 includes an internal electrode 61 a leading from the inside and an inward end portion 61 b .",
"As shown in FIG. 10 , the end portion 62 b of the conductor pattern 62 is connected to the end portion 61 b of the conductor pattern 61 by a through hole 74 b ′ in the non-magnetic layer 74 , which is shown also in FIG. 8 .",
"This defines the secondary coil 6 - 2 , which is spiral, and which uses the internal electrodes 62 a and 61 a as two ends of the secondary coil 6 - 2 .",
"[0055] In addition, two leads of the internal electrodes 54 a and 62 a are connected by a through hole 74 j in the non-magnetic layer 72 .",
"[0056] As shown in FIG. 1 , the non-magnetic layer 75 is laminated on the conductor patterns 54 and 61 , and the magnetic substrate 2 - 2 is bonded to the non-magnetic layer 75 .",
"[0057] External electrodes 4 - 1 to 4 - 6 are disposed outside the laminate 3 having the above-described structure.",
"[0058] This allows the external electrode 4 - 1 to electrically connect to both the internal electrodes 52 a and 64 a of the conductor patterns 52 and 64 , and allows the external electrode 4 - 2 to electrically connect to the internal electrode 51 a of the conductor pattern 51 .",
"Also, the external electrode 4 - 3 electrically connects to the internal electrode 61 a of the conductor pattern 61 .",
"The external electrode 4 - 4 electrically connects to both the internal electrodes 53 a and 63 a of the conductor patterns 53 and 63 .",
"The external electrode 4 - 5 electrically connects to both the internal electrodes 54 a and 62 a of the conductor patterns 54 and 62 .",
"[0059] FIG. 11 is a schematic diagram showing an electrical structure of the first and second transformers 5 and 6 .",
"[0060] On the basis of the above connections between the conductor patterns and the above connections between the external electrodes 4 - 1 to 4 - 6 and the internal electrodes, the electrical structure has the circuit structure shown in FIG. 11 .",
"[0061] In other words, the external electrode 4 - 2 connected to the internal electrode 51 a of the primary coil 5 - 1 of the first transformer 5 can be used as an input terminal for a main signal, and the external electrode 4 - 1 connected to the internal electrode 52 a can be used as an output terminal for the main signal.",
"The external electrode 4 - 4 connected to the internal electrode 53 a of the secondary coil 5 - 2 can be used as a ground terminal.",
"The internal electrode 64 a of the primary coil 6 - 1 of the second transformer 6 is connected to the internal electrode 52 a of the primary coil, and the internal electrode 63 a is connected to the internal electrode 53 a of the secondary coil 5 - 2 of the first transformer 5 .",
"The internal electrode 62 a of the secondary coil 6 - 2 is connected to the internal electrode 54 a of the secondary coil 5 - 2 of the first transformer 5 .",
"Accordingly, the external electrode 4 - 3 connected to the internal electrode 61 a of the secondary coil 6 - 2 can be used as an output terminal for a sub-signal, and the external electrode 4 - 5 connected to both the internal electrodes 54 a and 62 a can be used as a terminating end by a terminating resistor or the like, which is not shown.",
"[0062] This circuit structure is preferably identical to a circuit structure of the directional coupler 100 shown in FIG. 15 .",
"This multilayer directional coupler has a function of distributing and outputting the main signal input from the external electrode 4 - 2 to the external electrode 4 - 1 and 4 - 3 .",
"Needless to say, when inputting the main signal from the external electrode 4 - 3 , the multilayer directional coupler has a function of distributing and outputting the input main signal to the external electrodes 4 - 5 and 4 - 2 .",
"[0063] As described above, the multilayer directional coupler has a function of distributing and outputting the main signal.",
"The distribution ratios are determined according to the degree of electromagnetic coupling occurring between the first and second transformers, such as electromagnetic coupling between the primary and secondary coils 5 - 1 and 5 - 2 of the first transformer 5 , and electromagnetic coupling between the primary and secondary coils 6 - 1 and 6 - 2 of the second transformer 6 .",
"The degree of electromagnetic coupling is dependent on the winding length ratio N 1 of the secondary coil 5 - 2 to the primary coil 5 - 1 of the first transformer 5 and the winding length ratio N 2 of the primary coil 6 - 1 to the secondary coil 6 - 2 of the second transformer 6 .",
"[0064] FIG. 12 is a graph showing the winding length ratios (N 1 , N 2 ) and the degree of coupling of the multilayer directional coupler.",
"As a result of performing simulation in order to identify a range of the winding length ratios (N 1 , N 2 ) at which the first and second transformers have a good degree of coupling therebetween, the present inventors obtained the results shown in FIG. 12 .",
"Specifically, it was discovered that, as indicated by curve S in FIG. 12 , the degree of coupling between the first and second transformers 5 and 6 had good values of approximately 2 dB to 20 dB in a range in which a winding length ratio (1N 2 ) was not less than about 1 and not greater than about 10.",
"Accordingly, the winding length ratios N 1 and N 2 are preferably set so that 1<N 1 ≦10 and 1<N 2 ≦10.",
"[0065] Specifically, in this example of preferred embodiments of the present invention, the primary coil 5 - 1 , whose winding length was about “4.2 mm”",
"was pattern-formed, and the secondary coil 5 - 2 , whose winding length was about “10.5 mm”",
"was pattern-formed, with the winding length ratio N 1 set to about “2.5.”",
"Also, the primary coil 6 - 1 , whose winding length was about “4.2 mm”, was pattern-formed, and the secondary coil 6 - 2 , whose winding length was about “10.5 mm”, was pattern-formed, with the winding length ratio N 2 set to about “2.5.”",
"In addition, by setting a ratio (N 2 /N 1 ) of the winding length ratio N 2 to the winding length ratio N 1 so that 0.5<N 2 /N 1 <2.0, an impedance of each port can be improved.",
"Accordingly, in this example of the preferred embodiments, the ratio N 2 /N 1 was set to approximately “1.”",
"[0066] In this example of the preferred embodiments, since the first and second transformers 5 and 6 are formed by a known laminating technology such as photolithography, the primary and secondary coils 5 - 1 and 5 - 2 of the first transformer 5 and the primary and secondary coils 6 - 1 and 6 - 2 of the second transformer 6 can be pattern-formed so as to have preferable winding lengths.",
"Accordingly, the winding length ratios N 1 and N 2 of the first and second transformers can be finely and accurately set.",
"[0067] Next, the operation and advantages exhibited by the multilayer directional coupler according to the preferred embodiments are described.",
"[0068] As shown in FIG. 13 , the external electrodes 4 - 1 and 4 - 2 are connected to end portions of a main line 200 , with the external electrode 4 - 2 used as an input terminal for main signal S, and the external electrode 4 - 1 used as an output terminal.",
"The external electrode 4 - 4 is set to a ground state.",
"The external electrode 4 - 5 is grounded via a terminating resistor or the like, and the external electrode 4 - 3 is connected to a sub-line 201 and is used as an output terminal for sub-signal S 2 .",
"[0069] Accordingly, by transmitting main signal S through the main line 200 , main signal S is input from the external electrode 4 - 2 to the multilayer directional coupler 1 .",
"Then, main signal S 1 is output from the external electrode 4 - 1 to the main line 200 , and sub-signal S 2 is output from the external electrode 4 - 3 to the sub-line 201 .",
"In other words, main signal S input to the multilayer directional coupler 1 is distributed and output to the main line 200 and the sub-line 201 at an optimal distribution ratio corresponding to the winding length ratios N 1 and N 2 of the first and second transformers 5 and 6 and the ratio N 2 /N 1 .",
"[0070] With the first and second transformers 5 and 6 that are identical in circuit structure to the multilayer directional coupler 100 having the circuit structure in FIG. 15 , main signal S can be distributed as main signal S 1 and sub-signal S 2 in a wide band.",
"Thus, the multilayer directional coupler 1 can be used even for an apparatus that needs a signal having a bandwidth ratio equal to or greater than 90%, such as a television signal.",
"[0071] The present invention is not limited to the above-described preferred embodiments and may be variously modified and altered within the sprit of the present invention.",
"[0072] For example, although, in the foregoing preferred embodiments, the winding length ratio N 1 (winding length ratio N 2 ) of the secondary coil 5 - 2 (the primary coil 6 - 1 ) to the primary coil 5 - 1 (the secondary coil 6 - 2 ) of the first transformer 5 (the second transformer 6 ) is preferably set to about “2.5”, each of the winding length ratios N 1 and N 2 may be a value that is greater than about 1 and not greater than about 10, and is not limited the value set in the foregoing preferred embodiments.",
"In addition, although N 2 /N 1 is preferably set to about “1”, this ratio is not limited to this value since this ratio may be a value that is greater than about 0.5 and less than about 2.0.",
"[0073] While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention.",
"The scope of the present invention, therefore, is to be determined solely by the following claims."
] |
This application claims the benefit of U.S. Provisional Application No. 60/788,714 filed Apr. 4, 2006, which is hereby incorporated by reference in its entirety.
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to the field of treatment of wastewater and process water, more specifically, to the reduction in the level of ammonia and organic ammonia compounds in wastewater and process water, regardless of source.
BACKGROUND OF THE INVENTION
Human and animal waste is the primary source of nitrogen in most wastewater discharges. In addition, certain process waters, including but not limited to industrial process waters, contain significant amounts of nitrogen compounds. Wastewater containing nitrogen compounds such as ammonia; organic nitrogen, nitrates, and nitrites that contaminate ground and surface water resources are a major concern in a world facing potable water shortages. Traditional wastewater systems do little or nothing to reduce the level of nitrogen in the released wastewater. No low-cost technology is available to directly remove ammonia from wastewater. Release of these nitrogen compounds to environmental surface water, or especially ground water, is to be avoided. In addition, the removal of nitrogen compounds from certain processes using this method may be advantageous.
Existing systems of wastewater treatment are limited to treating wastewater with bacterial digestion, oxidation, settling, and disinfection (usually using chlorination). More advanced methods, such as ozone and ultraviolet radiation, also are used to treat water and wastewater. There are no existing systems in which wastewater containing ammonia is treated to directly remove ammonia from the water. Existing systems discuss sterilization, oxidation, and biological systems but not electro-chemical technologies.
It is known to use of ozone alone to sterilize water and/or treat the organic content water. For example, U.S. Pat. No. 4,007,120 issued to Bowen, and entitled “Oxidation and ozonation chamber”, describes the use of ozone to treat and disinfect water. U.S. Pat. No. 4,053,399 issued to Donnelly, et al. and entitled “Method and system for waste treatment”, describes the use of ozone to oxidize and disinfect wastewater. U.S. Pat. No. 4,176,061 issued to Stopka, and entitled “Apparatus and method for treatment of fluid with ozone”, describes the use of ozone in the form of micro-bubbles to oxidize and to disinfect wastewater. U.S. Pat. No. 4,255,257 issued to Greiner, et al. and entitled “Process for the treatment of water”, describes the use of pressurized ozone to treat water. U.S. Pat. No. 4,545,716 issued to Boeve, and entitled “Method of producing ultrapure, pyrogen-free water”, describes the use of highly-concentrated, substantially-pure ozone to treat deionized water. U.S. Pat. No. 4,572,821 issued to Brodard, et al. and entitled “Apparatus for dissolving ozone in a fluid”, describes the use of pressurized ozone to treat water. U.S. Pat. No. 5,130,032 issued to Sartori, and entitled “Method for treating a liquid medium”, describes the use of ultrasound to disperse ozone in water and the use of ultrasound to aid in the cleanup of ozonated water. U.S. Pat. No. 5,207,993 issued to Burris, and entitled “Batch liquid purifier”, describes the use of ozone in water with recirculation of the water through the ozone injection region to purify water. U.S. Pat. No. 5,868,945 issued to Morrow, et al. and entitled “Process of treating produced water with ozone”, describes the use of ozone to treat water, containing hydrocarbons, at elevated temperatures. U.S. Pat. No. 6,006,387 issued to Cooper, et al. and entitled “Cold water ozone disinfection”, describes the use of ozone dissolved in water to disinfect mechanical assemblies. U.S. Pat. No. 6,115,862 issued to Cooper, et al. and entitled “Cold water ozone disinfection”, describes the use of ozone dissolved in water to disinfect mechanical assemblies. The disclosures of each of these references are herein incorporated by reference to the extent that they are not inconsistent with this application.
There also are disclosures relating to the use of oxidation, singly, to treat wastewater or water. For example, U.S. Pat. No. 3,992,295 issued to Box Jr., et al. and entitled “Polluted water purification”, describes a process of catalyzed oxidation. U.S. Pat. No. 4,141,829 issued to Thiel, et al. and entitled “Process for wet oxidation of organic substances”, describes a process of oxidation occurring at elevated temperatures. U.S. Pat. No. 4,604,215 issued to McCorquodale, and entitled “Wet oxidation”, describes a process of oxidation occurring at elevated temperatures. U.S. Pat. No. 4,699,720 issued to Harada, et al. and entitled “Process for treating waste water by wet oxidations”, describes a process of oxidation using catalysts. U.S. Pat. No. 4,793,919 issued to McCorquodale, and entitled “Wet oxidation system”, describes a process of oxidation occurring with mixing or stirring of the fluid. U.S. Pat. No. 5,053,142 issued to Sorensen, et al. and entitled “Method for treating polluted material”, describes a process of oxidation occurring in a fluid. U.S. Pat. No. 5,057,220 issued to Harada, et al. and entitled “Process for treating waste water”, describes a process of oxidation using catalysts. U.S. Pat. No. 5,145,587 issued to Ishii, et al. and entitled “Method for treatment of waste water”, describes a process of oxidation at elevated temperatures. U.S. Pat. No. 5,158,689 issued to Ishii, et al. and entitled “Method for purification of waste water”, describes a process of oxidation at elevated temperatures.
Additionally, U.S. Pat. No. 5,370,801 issued to Sorensen, et al. and entitled “Method for treating polluted material”, describes a process of oxidation occurring in a fluid. U.S. Pat. No. 5,614,087 issued to Le, and entitled “Wet oxidation system”, describes a process of oxidation occurring in a stirred or mixed fluid. U.S. Pat. No. 5,807,484 issued to Couture, et al. and entitled “Waste water treatment”, describes a process of oxidation using trickle filters. U.S. Pat. No. 5,888,389 issued to Griffith, et al. and entitled “Apparatus for oxidizing undigested wastewater sludges”, describes a process of supercritical oxidation occurring in a fluid at elevated temperatures and pressures.
No systems exist in the field of electrolytic removal of ammonia by direct electrolysis or by high pH chemical conversion at an electrolytic electrode. Needs exist for new systems of electrolytic removal of ammonia by direct electrolysis or by high pH chemical conversion at an electrolytic electrode.
SUMMARY OF THE INVENTION
A method is disclosed that directly removes ammonia (ammonium) from clarified wastewater. Further a system is disclosed that applies this method to treat and to remove specified levels of ammonia from wastewater and other process waters.
Human and animal waste can be treated by physical, chemical, or biological means such as: aerobic digestion, anaerobic digestion, advanced oxidation, chemical action, filtration, and solids separation. While major reductions in solids can be expected using these conventional processes, there is little reduction in nitrogen containing compounds, particularly ammonia.
A primary result of this invention is to directly remove ammonia in its aqueous form from wastewater or other process waters. Ammonia in water is typically in the form of ammonium ion —NH 4 . This is a form that is readily used by plants and is one major cause of algae and plant growth in the environment where wastewater is discharged.
This invention provides a simple and direct method to remove aqueous ammonia by electro-chemistry and electrolysis. Metallic electrodes are placed into the wastewater stream. A direct current voltage is applied to the plate electrodes; and current flows from the anode to the cathode. Electrolysis of the water occurs, generating oxygen at the anode and hydrogen at the cathode. This electrolysis has another important effect. The pH at the cathode is increased. We find that the pH at or near the cathode can exceed 9. At this pH aqueous ammonia is converted to ammonia gas. The addition of air at or below the cathode sparges the ammonia from the water and removes it from the system. The ionic polarity of the ammonium has an important secondary effect. Ammonium is directly attracted to the anode, and, in some conditions, electrolysis of the ammonium into ammonia occurs. Again, the addition of air at the anode sparges the ammonia, removing it from the system.
Approximately up to 98%, or more, of ammonia is removed from the overall wastewater stream using a system based on this inventive method.
The configuration described has a number of advantages. The ammonia is removed from the system with the application of electrical energy. There are no waste products. The ammonia that is removed from the wastewater can be recovered using standard refrigeration techniques and can result in a valuable byproduct fertilizer. Unlike biological solutions, our invention does not rely on living organisms for the success of the process. The process described herein is unlikely to be upset or interrupted by the presence of materials that are toxic to the organisms necessary for biological systems to operate.
It is therefore an object of the invention to describe a method and to provide a system and an apparatus for the treatment and/or removal of ammonia-containing compounds from wastewater or process waters that greatly reduces the level of ammonia reaching the environment.
These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram of the method of the invention.
FIG. 2 is a schematic of one embodiment of the invention wherein the electrodes have a defined physical separation.
FIG. 3 is a schematic a second embodiment of the invention wherein closely spaced electrodes are mechanically separated by a thin porous membrane.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Two embodiments of a method of ammonia removal are disclosed herein. The embodiments differ in their potential electrical efficiency, but otherwise operate similarly. Those skilled in the art may recognize that other embodiments are possible but we decline to list all possible combinations herein.
The ammonia removal from the waste or process stream can reach approximately 90% to 98%, or higher, using the inventive system described below.
One embodiment of the system consists of one or more pairs of electrode plates arranged in a substantially planar fashion. The effectiveness of this or other embodiments is not impacted by the use of other geometries such as cylindrical geometries. The electrodes must be fabricated from corrosion resistant materials such as, but not limited to, titanium, platinum, or gold. Coatings may be placed on the titanium. These coatings may retard corrosion of the substrate and may aid in the efficiency of the electrolysis process. These coatings may consist of, but are not limited to, thin layers of such oxides as rhenium oxide, zirconium oxide, and rhodium oxide.
The embodiment uses, but is not limited to, electrodes whose width is 30 centimeters (cm) and whose length is 100 cm. This results in an electrode area of ˜3000 square centimeters (cm 2 ). Electrode dimensions can range from a few cm to hundreds of cm and are limited only by the physical constraints of the application and the engineering required to hold the electrode spacing to adequate tolerances. The electrodes are held in position using insulating spacers located at arbitrary points, but ideally near the edges of the plates where the flow of wastewater is not impeded. The sole purpose of the insulating spacers is to provide for the positive location of the electrodes, thus preventing the accidental shorting of the electrodes.
A voltage, typically, but not limited to, 4.5 V, is placed between the electrodes. The applied voltage can span the range of between 3.0 V and 50 V depending in the spacing of the electrodes and the conductivity (salinity) of the water. It is advantageous to keep the current density on the electrodes below 0.15 amperes (A) per cm 2 in order to maximize the electrode lifetime. In any case the successful operation of this embodiment is not significantly impacted by the absolute magnitude of the current on the electrodes.
In operation, electrical current flows uniformly through the water between the plates. This current heats the water and is a parasitic loss and has no beneficial action. It is therefore advantageous to operate with the electrode spacing as small as is mechanically possible. The spacing is typically limited by the flatness of the electrodes, particle content of the wastewater, and the operational safety margin desired for the system. The first embodiment uses, but is not limited to, a spacing of 3 millimeters (3 mm). Smaller electrode spacings permit lower operational voltages for the system. Voltage regulation provides no added performance to the system. During electrolytic cell operation, the pH of the water near the cathode increases to level>9. At or above a pH of 9, aqueous ammonium (NH 4 ) is converted to gaseous ammonia (NH 3 ).
Wastewater flows through the space between the plates. In this embodiment the water flows from the bottom of the electrodes to the top. Other water flow patterns are possible but upward flow assists in the removal of gaseous ammonia from the volume between the plates.
Fine bubbles of air are injected into the volume of water at the bottom of the electrode plates. The air flows upwards along and between the electrodes. This air carries with it gases generated at the electrodes including the ammonia released by the electro-chemical and electrolytic process. This gas can be released directly to the air if regulations permit or the ammonia in the gas stream can be captured using standard condensation techniques.
Under normal operation this embodiment at a voltage of 4.5 V will conduct a total current of ˜100 A per electrode pair. An embodiment consisting of multiple electrode pairs will draw a total current in multiples of the base 100 A per electrode pair. Someone skilled in the art will recognize that multiple electrodes can be electrically connected either in series or in parallel depending on the necessities of a particular installation. At an operational voltage of 4.5 V the embodiment as described will consume a peak electrical power of 450 watts (W) per electrode pair.
A second embodiment of the system consists of one or more pairs of porous electrodes arranged in a substantially planar fashion. The effectiveness of this or other embodiments is not impacted by the use of other geometries such as cylindrical geometries. The porosity of the electrodes is needed in order to maintain a flow of wastewater through the cell. The electrodes are fabricated from corrosion resistant materials such as but not limited to titanium. Other coatings may be placed on the titanium. These coatings may consist of, but are not limited to, thin layers of such oxides as rhenium oxide, zirconium oxide, and rhodium oxide.
The embodiment uses, but is not limited to, electrodes whose width is 30 cm and whose length is 100 cm. This results in an electrode area of ˜3000 cm 2 . Electrode dimensions can range from a few cm to hundreds of cm and are limited only by the physical constraints of the application and the engineering required to hold the electrode spacing to adequate tolerances.
The electrodes are positioned closely together using an insulating membrane with a thickness of 1 mm. The membrane materials are such as but not limited to Nafion 450™ to separate the anode from the cathode. The anode is typically on the effluent side and is used to protect the membrane from fouling with organics. The sole purpose of the thin membrane is to provide for the smallest possible spacing of the electrodes, thus minimizing the operational voltage and, hence, power. A voltage, typically, but not limited to, 1.5 V, is placed between the electrodes. The applied voltage can span the range of between 1.0 V and 50 V depending in the thickness of the membrane and the conductivity (salinity) of the water.
In operation current flows through the water saturated membrane between the plates. This current heats the water and is a parasitic loss and has no beneficial action. It is therefore advantageous to operate with thinnest membrane possible. The spacing is typically limited by the uniformity of the membrane and the operational safety margin desired for the system. The second embodiment uses, but is not limited to, a membrane thickness of 1 mm. During electrolytic cell operation, the pH of the water near the cathode increases to level>pH 9. At or above a pH of 9, aqueous ammonium (NH 4 ) is converted to gaseous ammonia (NH 3 ).
Wastewater flows through the electrodes and the membrane. In this embodiment the water flows from the bottom of the electrodes to the top. But the flow is arranged to move through the anode, the membrane, and out the cathode. Other water flow patterns are possible but flow through the anode refreshes the water in the membrane and the upward flow assists in the removal of gaseous ammonia from the volume between the plates.
Fine bubbles of air are injected into the volume of water at the bottom of the cathode. The air flows upwards along and between the cathodes. This air carries with it gases generated at the electrodes including the ammonia released by the electro-chemical and electrolytic process. This gas can be released directly to the air if regulations permit or the ammonia in the gas stream can be captured using standard condensation techniques.
Under normal operation at a voltage of 1.5 V the second embodiment will conduct a total current of ˜100 A per electrode pair. An embodiment consisting of multiple electrode pairs will draw a total current in multiples of 100-A per electrode pair. Someone skilled in the art will quickly recognize that the electrodes can be electrically connected either in series or in parallel depending on the necessities of a particular installation. At an operational voltage of 1.5 V the embodiment as described will consume a peak electrical power of 150 W per electrode pair. Note the power consumption of the second embodiment is 33% of that used by the first embodiment.
All embodiments of this invention suffer from the accumulation of mineral deposits on the cathode. The most common of these deposits is calcium carbonate. Calcium and other metal anions move to the cathode where the high pH of the water takes the carbonates from solution. If left unchecked this would eventually completely cover the electrode and prevent the successful operation of the system. Three methods for preventing the build up of carbonates are possible. First, reversing the polarity of the plates on a regular basis removes the built up deposits. If the cathode becomes the anode the acidic environment will dissolve the carbonate buildup. Second, the application of a moderate level of ultrasonic acoustic energy prevents the build up of mineral deposits. Third, frequent abrasion of the surface with a mechanical scrubber prevents the excessive buildup of minerals. In the case of the membrane used in embodiment two, an occasional detergent wash may be necessary to remove greases and oils that may accumulate in the membrane. The oxygen generated from the anode side assists membrane cleanliness.
The preferred method to keep the surface clean is an engineering decision based on the many tradeoffs that must be made for any particular implementation. In principle, the formation of mineral deposits can be totally eliminated by having a waste stream consisting of softened water. For large volumes of water this is impractical.
Reference is made to FIGS. 1-3 . FIG. 1 is a flow diagram of the method of the invention. The cell electrodes, electrical systems, wastewater flow, an air/ammonia components found in the invention are described. The ammoniated waste water inputs at the bottom of the electrodes and exits at the top. Air containing ammonia is vented at the top of the system. FIG. 2 provides a detailed schematic view of the components and arrangement of the first embodiment. A schematic of a second embodiment using porous membranes is seen in FIG. 3 .
FIG. 1 shows the block diagram of the method for ammonia removal. Wastewater 1 flows into the lower portion of the treatment tank 2 . An assembly of planar electrodes 3 is suspended in the treatment tank 2 . Voltage is applied to the electrode with a direct current power supply 4 . Air 5 is supplied with a low pressure bubbling system 6 (e.g. venturi air injection). Ammonia gas 7 is released below the electrode assembly 3 . The injected air 5 sparges the released ammonia 7 and the resulting gas mixture 8 is exhausted from the treatment tank 2 . The treated wastewater 9 leaves the treatment tank 2 near the top of the tank.
FIG. 2 shows a detailed schematic of the first embodiment. Wastewater 11 flows into a canister filter 12 (or equivalent) to ensure that the water has no significant particle content. The filtered wastewater 13 flows in the treatment unit 14 . The treatment unit 14 contains an electrical series configuration of electrolysis electrodes 16 . The treatment unit 14 consists of a sandwich of hollow insulating plastic plates 15 and electrolysis electrodes 16 . The insulating plates can be composed of any suitable plastic such as but not limited to acrylic, polycarbonate, Teflon, or PVC. The insulating plastic plates 15 serve to precisely space the electrodes 16 and electrically isolate them. Water is fed into a series of distribution holes 17 located at the bottom of each cell (between the electrodes 16 ). The number, size, and length of the holes are determined by the need to minimize the leakage electrical current flowing around the plates. In the water distribution manifold sparging air 18 is injected. This sparging air 18 rises between the electrodes. A direct current power supply 19 applies voltage to the electrodes 16 at the first electrode plate 20 and the last electrode plate 21 . The applied voltage per cell is the total applied voltage divided by the number of electrolysis cells 15 in the treatment unit 14 . Ammonia gas 22 is formed on the electrodes 16 . The sparging air 18 to the exhaust 24 carries gaseous ammonia 22 away. The resultant gas mixture flows from the treatment unit 14 where it is exhausted or potentially recovered. An ultrasonic transducer 23 applies sonic energy to the electrolysis cells 15 to prevent the build up of carbonate on the electrodes 16 . The treated wastewater 25 exits the treatment unit 14 .
FIG. 3 shows a close up detailed schematic of the second embodiment. The schematic for FIG. 3 is similar to that of FIG. 2 except that the space between electrodes of opposite polarity is filled with a porous membrane and the spacing is reduced. Wastewater 30 flows into a canister filter 31 (or equivalent) to ensure that the water has no significant particle content. The filtered wastewater 32 flows in the treatment unit 33 . The treatment unit 33 contains an electrical series configuration of electrolysis electrodes 34 consisting of a sandwich of hollow insulating plastic positioning plates 35 and hollow porous electrolysis electrodes 34 . The insulating plates can be composed of any suitable plastic such as but not limited to acrylic, polycarbonate, Teflon, or PVC. The insulating plastic plates 35 serve to precisely position the electrodes 34 together, to clamp the electrodes onto the 1-mm thick membrane 36 , and electrically isolate the electrodes 34 . Water is fed through holes 42 in the bottom plastic positioning plates 35 into one set of electrodes and is exhausted at the top of adjacent porous electrodes of opposite polarity. Sparging air 37 is injected into the hollow electrodes 34 as needed. A direct current power supply 38 applies voltage to the electrodes 34 at the first electrode plate 39 and the last electrode plate 40 . The applied voltage per electrode pair (a cell) is the total applied voltage divided by the total number of electrolysis cells. Ammonia gas 41 is formed on the surface of the electrodes 34 . Gaseous ammonia 41 migrates into the hollow electrodes and is carried away by the sparging air 37 and water. The treated wastewater 43 , having passed through the electrolysis system, exits the treatment unit 33 .
While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention. | A method and system are described to treat ammonia-containing wastewater or process waters. Sewage containing human or animal waste and certain process liquids, typically water, contains high levels of nitrogen in the form of ammonia. An electro-chemical method to extract the ammonia from the wastewater is also described. The system described is one implementation of this method. One or more electrolysis cells convert ammonium to ammonia where the generated ammonia gas can readily be extracted for disposal or reuse. Such a system can involve electrolysis cells of numerous types as described herein. | Summarize the patent document, focusing on the invention's functionality and advantages. | [
"This application claims the benefit of U.S. Provisional Application No. 60/788,714 filed Apr. 4, 2006, which is hereby incorporated by reference in its entirety.",
"TECHNICAL FIELD OF THE INVENTION The present invention relates generally to the field of treatment of wastewater and process water, more specifically, to the reduction in the level of ammonia and organic ammonia compounds in wastewater and process water, regardless of source.",
"BACKGROUND OF THE INVENTION Human and animal waste is the primary source of nitrogen in most wastewater discharges.",
"In addition, certain process waters, including but not limited to industrial process waters, contain significant amounts of nitrogen compounds.",
"Wastewater containing nitrogen compounds such as ammonia;",
"organic nitrogen, nitrates, and nitrites that contaminate ground and surface water resources are a major concern in a world facing potable water shortages.",
"Traditional wastewater systems do little or nothing to reduce the level of nitrogen in the released wastewater.",
"No low-cost technology is available to directly remove ammonia from wastewater.",
"Release of these nitrogen compounds to environmental surface water, or especially ground water, is to be avoided.",
"In addition, the removal of nitrogen compounds from certain processes using this method may be advantageous.",
"Existing systems of wastewater treatment are limited to treating wastewater with bacterial digestion, oxidation, settling, and disinfection (usually using chlorination).",
"More advanced methods, such as ozone and ultraviolet radiation, also are used to treat water and wastewater.",
"There are no existing systems in which wastewater containing ammonia is treated to directly remove ammonia from the water.",
"Existing systems discuss sterilization, oxidation, and biological systems but not electro-chemical technologies.",
"It is known to use of ozone alone to sterilize water and/or treat the organic content water.",
"For example, U.S. Pat. No. 4,007,120 issued to Bowen, and entitled “Oxidation and ozonation chamber”, describes the use of ozone to treat and disinfect water.",
"U.S. Pat. No. 4,053,399 issued to Donnelly, et al.",
"and entitled “Method and system for waste treatment”, describes the use of ozone to oxidize and disinfect wastewater.",
"U.S. Pat. No. 4,176,061 issued to Stopka, and entitled “Apparatus and method for treatment of fluid with ozone”, describes the use of ozone in the form of micro-bubbles to oxidize and to disinfect wastewater.",
"U.S. Pat. No. 4,255,257 issued to Greiner, et al.",
"and entitled “Process for the treatment of water”, describes the use of pressurized ozone to treat water.",
"U.S. Pat. No. 4,545,716 issued to Boeve, and entitled “Method of producing ultrapure, pyrogen-free water”, describes the use of highly-concentrated, substantially-pure ozone to treat deionized water.",
"U.S. Pat. No. 4,572,821 issued to Brodard, et al.",
"and entitled “Apparatus for dissolving ozone in a fluid”, describes the use of pressurized ozone to treat water.",
"U.S. Pat. No. 5,130,032 issued to Sartori, and entitled “Method for treating a liquid medium”, describes the use of ultrasound to disperse ozone in water and the use of ultrasound to aid in the cleanup of ozonated water.",
"U.S. Pat. No. 5,207,993 issued to Burris, and entitled “Batch liquid purifier”, describes the use of ozone in water with recirculation of the water through the ozone injection region to purify water.",
"U.S. Pat. No. 5,868,945 issued to Morrow, et al.",
"and entitled “Process of treating produced water with ozone”, describes the use of ozone to treat water, containing hydrocarbons, at elevated temperatures.",
"U.S. Pat. No. 6,006,387 issued to Cooper, et al.",
"and entitled “Cold water ozone disinfection”, describes the use of ozone dissolved in water to disinfect mechanical assemblies.",
"U.S. Pat. No. 6,115,862 issued to Cooper, et al.",
"and entitled “Cold water ozone disinfection”, describes the use of ozone dissolved in water to disinfect mechanical assemblies.",
"The disclosures of each of these references are herein incorporated by reference to the extent that they are not inconsistent with this application.",
"There also are disclosures relating to the use of oxidation, singly, to treat wastewater or water.",
"For example, U.S. Pat. No. 3,992,295 issued to Box Jr., et al.",
"and entitled “Polluted water purification”, describes a process of catalyzed oxidation.",
"U.S. Pat. No. 4,141,829 issued to Thiel, et al.",
"and entitled “Process for wet oxidation of organic substances”, describes a process of oxidation occurring at elevated temperatures.",
"U.S. Pat. No. 4,604,215 issued to McCorquodale, and entitled “Wet oxidation”, describes a process of oxidation occurring at elevated temperatures.",
"U.S. Pat. No. 4,699,720 issued to Harada, et al.",
"and entitled “Process for treating waste water by wet oxidations”, describes a process of oxidation using catalysts.",
"U.S. Pat. No. 4,793,919 issued to McCorquodale, and entitled “Wet oxidation system”, describes a process of oxidation occurring with mixing or stirring of the fluid.",
"U.S. Pat. No. 5,053,142 issued to Sorensen, et al.",
"and entitled “Method for treating polluted material”, describes a process of oxidation occurring in a fluid.",
"U.S. Pat. No. 5,057,220 issued to Harada, et al.",
"and entitled “Process for treating waste water”, describes a process of oxidation using catalysts.",
"U.S. Pat. No. 5,145,587 issued to Ishii, et al.",
"and entitled “Method for treatment of waste water”, describes a process of oxidation at elevated temperatures.",
"U.S. Pat. No. 5,158,689 issued to Ishii, et al.",
"and entitled “Method for purification of waste water”, describes a process of oxidation at elevated temperatures.",
"Additionally, U.S. Pat. No. 5,370,801 issued to Sorensen, et al.",
"and entitled “Method for treating polluted material”, describes a process of oxidation occurring in a fluid.",
"U.S. Pat. No. 5,614,087 issued to Le, and entitled “Wet oxidation system”, describes a process of oxidation occurring in a stirred or mixed fluid.",
"U.S. Pat. No. 5,807,484 issued to Couture, et al.",
"and entitled “Waste water treatment”, describes a process of oxidation using trickle filters.",
"U.S. Pat. No. 5,888,389 issued to Griffith, et al.",
"and entitled “Apparatus for oxidizing undigested wastewater sludges”, describes a process of supercritical oxidation occurring in a fluid at elevated temperatures and pressures.",
"No systems exist in the field of electrolytic removal of ammonia by direct electrolysis or by high pH chemical conversion at an electrolytic electrode.",
"Needs exist for new systems of electrolytic removal of ammonia by direct electrolysis or by high pH chemical conversion at an electrolytic electrode.",
"SUMMARY OF THE INVENTION A method is disclosed that directly removes ammonia (ammonium) from clarified wastewater.",
"Further a system is disclosed that applies this method to treat and to remove specified levels of ammonia from wastewater and other process waters.",
"Human and animal waste can be treated by physical, chemical, or biological means such as: aerobic digestion, anaerobic digestion, advanced oxidation, chemical action, filtration, and solids separation.",
"While major reductions in solids can be expected using these conventional processes, there is little reduction in nitrogen containing compounds, particularly ammonia.",
"A primary result of this invention is to directly remove ammonia in its aqueous form from wastewater or other process waters.",
"Ammonia in water is typically in the form of ammonium ion —NH 4 .",
"This is a form that is readily used by plants and is one major cause of algae and plant growth in the environment where wastewater is discharged.",
"This invention provides a simple and direct method to remove aqueous ammonia by electro-chemistry and electrolysis.",
"Metallic electrodes are placed into the wastewater stream.",
"A direct current voltage is applied to the plate electrodes;",
"and current flows from the anode to the cathode.",
"Electrolysis of the water occurs, generating oxygen at the anode and hydrogen at the cathode.",
"This electrolysis has another important effect.",
"The pH at the cathode is increased.",
"We find that the pH at or near the cathode can exceed 9.",
"At this pH aqueous ammonia is converted to ammonia gas.",
"The addition of air at or below the cathode sparges the ammonia from the water and removes it from the system.",
"The ionic polarity of the ammonium has an important secondary effect.",
"Ammonium is directly attracted to the anode, and, in some conditions, electrolysis of the ammonium into ammonia occurs.",
"Again, the addition of air at the anode sparges the ammonia, removing it from the system.",
"Approximately up to 98%, or more, of ammonia is removed from the overall wastewater stream using a system based on this inventive method.",
"The configuration described has a number of advantages.",
"The ammonia is removed from the system with the application of electrical energy.",
"There are no waste products.",
"The ammonia that is removed from the wastewater can be recovered using standard refrigeration techniques and can result in a valuable byproduct fertilizer.",
"Unlike biological solutions, our invention does not rely on living organisms for the success of the process.",
"The process described herein is unlikely to be upset or interrupted by the presence of materials that are toxic to the organisms necessary for biological systems to operate.",
"It is therefore an object of the invention to describe a method and to provide a system and an apparatus for the treatment and/or removal of ammonia-containing compounds from wastewater or process waters that greatly reduces the level of ammonia reaching the environment.",
"These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the drawings.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of the method of the invention.",
"FIG. 2 is a schematic of one embodiment of the invention wherein the electrodes have a defined physical separation.",
"FIG. 3 is a schematic a second embodiment of the invention wherein closely spaced electrodes are mechanically separated by a thin porous membrane.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Two embodiments of a method of ammonia removal are disclosed herein.",
"The embodiments differ in their potential electrical efficiency, but otherwise operate similarly.",
"Those skilled in the art may recognize that other embodiments are possible but we decline to list all possible combinations herein.",
"The ammonia removal from the waste or process stream can reach approximately 90% to 98%, or higher, using the inventive system described below.",
"One embodiment of the system consists of one or more pairs of electrode plates arranged in a substantially planar fashion.",
"The effectiveness of this or other embodiments is not impacted by the use of other geometries such as cylindrical geometries.",
"The electrodes must be fabricated from corrosion resistant materials such as, but not limited to, titanium, platinum, or gold.",
"Coatings may be placed on the titanium.",
"These coatings may retard corrosion of the substrate and may aid in the efficiency of the electrolysis process.",
"These coatings may consist of, but are not limited to, thin layers of such oxides as rhenium oxide, zirconium oxide, and rhodium oxide.",
"The embodiment uses, but is not limited to, electrodes whose width is 30 centimeters (cm) and whose length is 100 cm.",
"This results in an electrode area of ˜3000 square centimeters (cm 2 ).",
"Electrode dimensions can range from a few cm to hundreds of cm and are limited only by the physical constraints of the application and the engineering required to hold the electrode spacing to adequate tolerances.",
"The electrodes are held in position using insulating spacers located at arbitrary points, but ideally near the edges of the plates where the flow of wastewater is not impeded.",
"The sole purpose of the insulating spacers is to provide for the positive location of the electrodes, thus preventing the accidental shorting of the electrodes.",
"A voltage, typically, but not limited to, 4.5 V, is placed between the electrodes.",
"The applied voltage can span the range of between 3.0 V and 50 V depending in the spacing of the electrodes and the conductivity (salinity) of the water.",
"It is advantageous to keep the current density on the electrodes below 0.15 amperes (A) per cm 2 in order to maximize the electrode lifetime.",
"In any case the successful operation of this embodiment is not significantly impacted by the absolute magnitude of the current on the electrodes.",
"In operation, electrical current flows uniformly through the water between the plates.",
"This current heats the water and is a parasitic loss and has no beneficial action.",
"It is therefore advantageous to operate with the electrode spacing as small as is mechanically possible.",
"The spacing is typically limited by the flatness of the electrodes, particle content of the wastewater, and the operational safety margin desired for the system.",
"The first embodiment uses, but is not limited to, a spacing of 3 millimeters (3 mm).",
"Smaller electrode spacings permit lower operational voltages for the system.",
"Voltage regulation provides no added performance to the system.",
"During electrolytic cell operation, the pH of the water near the cathode increases to level>9.",
"At or above a pH of 9, aqueous ammonium (NH 4 ) is converted to gaseous ammonia (NH 3 ).",
"Wastewater flows through the space between the plates.",
"In this embodiment the water flows from the bottom of the electrodes to the top.",
"Other water flow patterns are possible but upward flow assists in the removal of gaseous ammonia from the volume between the plates.",
"Fine bubbles of air are injected into the volume of water at the bottom of the electrode plates.",
"The air flows upwards along and between the electrodes.",
"This air carries with it gases generated at the electrodes including the ammonia released by the electro-chemical and electrolytic process.",
"This gas can be released directly to the air if regulations permit or the ammonia in the gas stream can be captured using standard condensation techniques.",
"Under normal operation this embodiment at a voltage of 4.5 V will conduct a total current of ˜100 A per electrode pair.",
"An embodiment consisting of multiple electrode pairs will draw a total current in multiples of the base 100 A per electrode pair.",
"Someone skilled in the art will recognize that multiple electrodes can be electrically connected either in series or in parallel depending on the necessities of a particular installation.",
"At an operational voltage of 4.5 V the embodiment as described will consume a peak electrical power of 450 watts (W) per electrode pair.",
"A second embodiment of the system consists of one or more pairs of porous electrodes arranged in a substantially planar fashion.",
"The effectiveness of this or other embodiments is not impacted by the use of other geometries such as cylindrical geometries.",
"The porosity of the electrodes is needed in order to maintain a flow of wastewater through the cell.",
"The electrodes are fabricated from corrosion resistant materials such as but not limited to titanium.",
"Other coatings may be placed on the titanium.",
"These coatings may consist of, but are not limited to, thin layers of such oxides as rhenium oxide, zirconium oxide, and rhodium oxide.",
"The embodiment uses, but is not limited to, electrodes whose width is 30 cm and whose length is 100 cm.",
"This results in an electrode area of ˜3000 cm 2 .",
"Electrode dimensions can range from a few cm to hundreds of cm and are limited only by the physical constraints of the application and the engineering required to hold the electrode spacing to adequate tolerances.",
"The electrodes are positioned closely together using an insulating membrane with a thickness of 1 mm.",
"The membrane materials are such as but not limited to Nafion 450™ to separate the anode from the cathode.",
"The anode is typically on the effluent side and is used to protect the membrane from fouling with organics.",
"The sole purpose of the thin membrane is to provide for the smallest possible spacing of the electrodes, thus minimizing the operational voltage and, hence, power.",
"A voltage, typically, but not limited to, 1.5 V, is placed between the electrodes.",
"The applied voltage can span the range of between 1.0 V and 50 V depending in the thickness of the membrane and the conductivity (salinity) of the water.",
"In operation current flows through the water saturated membrane between the plates.",
"This current heats the water and is a parasitic loss and has no beneficial action.",
"It is therefore advantageous to operate with thinnest membrane possible.",
"The spacing is typically limited by the uniformity of the membrane and the operational safety margin desired for the system.",
"The second embodiment uses, but is not limited to, a membrane thickness of 1 mm.",
"During electrolytic cell operation, the pH of the water near the cathode increases to level>pH 9.",
"At or above a pH of 9, aqueous ammonium (NH 4 ) is converted to gaseous ammonia (NH 3 ).",
"Wastewater flows through the electrodes and the membrane.",
"In this embodiment the water flows from the bottom of the electrodes to the top.",
"But the flow is arranged to move through the anode, the membrane, and out the cathode.",
"Other water flow patterns are possible but flow through the anode refreshes the water in the membrane and the upward flow assists in the removal of gaseous ammonia from the volume between the plates.",
"Fine bubbles of air are injected into the volume of water at the bottom of the cathode.",
"The air flows upwards along and between the cathodes.",
"This air carries with it gases generated at the electrodes including the ammonia released by the electro-chemical and electrolytic process.",
"This gas can be released directly to the air if regulations permit or the ammonia in the gas stream can be captured using standard condensation techniques.",
"Under normal operation at a voltage of 1.5 V the second embodiment will conduct a total current of ˜100 A per electrode pair.",
"An embodiment consisting of multiple electrode pairs will draw a total current in multiples of 100-A per electrode pair.",
"Someone skilled in the art will quickly recognize that the electrodes can be electrically connected either in series or in parallel depending on the necessities of a particular installation.",
"At an operational voltage of 1.5 V the embodiment as described will consume a peak electrical power of 150 W per electrode pair.",
"Note the power consumption of the second embodiment is 33% of that used by the first embodiment.",
"All embodiments of this invention suffer from the accumulation of mineral deposits on the cathode.",
"The most common of these deposits is calcium carbonate.",
"Calcium and other metal anions move to the cathode where the high pH of the water takes the carbonates from solution.",
"If left unchecked this would eventually completely cover the electrode and prevent the successful operation of the system.",
"Three methods for preventing the build up of carbonates are possible.",
"First, reversing the polarity of the plates on a regular basis removes the built up deposits.",
"If the cathode becomes the anode the acidic environment will dissolve the carbonate buildup.",
"Second, the application of a moderate level of ultrasonic acoustic energy prevents the build up of mineral deposits.",
"Third, frequent abrasion of the surface with a mechanical scrubber prevents the excessive buildup of minerals.",
"In the case of the membrane used in embodiment two, an occasional detergent wash may be necessary to remove greases and oils that may accumulate in the membrane.",
"The oxygen generated from the anode side assists membrane cleanliness.",
"The preferred method to keep the surface clean is an engineering decision based on the many tradeoffs that must be made for any particular implementation.",
"In principle, the formation of mineral deposits can be totally eliminated by having a waste stream consisting of softened water.",
"For large volumes of water this is impractical.",
"Reference is made to FIGS. 1-3 .",
"FIG. 1 is a flow diagram of the method of the invention.",
"The cell electrodes, electrical systems, wastewater flow, an air/ammonia components found in the invention are described.",
"The ammoniated waste water inputs at the bottom of the electrodes and exits at the top.",
"Air containing ammonia is vented at the top of the system.",
"FIG. 2 provides a detailed schematic view of the components and arrangement of the first embodiment.",
"A schematic of a second embodiment using porous membranes is seen in FIG. 3 .",
"FIG. 1 shows the block diagram of the method for ammonia removal.",
"Wastewater 1 flows into the lower portion of the treatment tank 2 .",
"An assembly of planar electrodes 3 is suspended in the treatment tank 2 .",
"Voltage is applied to the electrode with a direct current power supply 4 .",
"Air 5 is supplied with a low pressure bubbling system 6 (e.g. venturi air injection).",
"Ammonia gas 7 is released below the electrode assembly 3 .",
"The injected air 5 sparges the released ammonia 7 and the resulting gas mixture 8 is exhausted from the treatment tank 2 .",
"The treated wastewater 9 leaves the treatment tank 2 near the top of the tank.",
"FIG. 2 shows a detailed schematic of the first embodiment.",
"Wastewater 11 flows into a canister filter 12 (or equivalent) to ensure that the water has no significant particle content.",
"The filtered wastewater 13 flows in the treatment unit 14 .",
"The treatment unit 14 contains an electrical series configuration of electrolysis electrodes 16 .",
"The treatment unit 14 consists of a sandwich of hollow insulating plastic plates 15 and electrolysis electrodes 16 .",
"The insulating plates can be composed of any suitable plastic such as but not limited to acrylic, polycarbonate, Teflon, or PVC.",
"The insulating plastic plates 15 serve to precisely space the electrodes 16 and electrically isolate them.",
"Water is fed into a series of distribution holes 17 located at the bottom of each cell (between the electrodes 16 ).",
"The number, size, and length of the holes are determined by the need to minimize the leakage electrical current flowing around the plates.",
"In the water distribution manifold sparging air 18 is injected.",
"This sparging air 18 rises between the electrodes.",
"A direct current power supply 19 applies voltage to the electrodes 16 at the first electrode plate 20 and the last electrode plate 21 .",
"The applied voltage per cell is the total applied voltage divided by the number of electrolysis cells 15 in the treatment unit 14 .",
"Ammonia gas 22 is formed on the electrodes 16 .",
"The sparging air 18 to the exhaust 24 carries gaseous ammonia 22 away.",
"The resultant gas mixture flows from the treatment unit 14 where it is exhausted or potentially recovered.",
"An ultrasonic transducer 23 applies sonic energy to the electrolysis cells 15 to prevent the build up of carbonate on the electrodes 16 .",
"The treated wastewater 25 exits the treatment unit 14 .",
"FIG. 3 shows a close up detailed schematic of the second embodiment.",
"The schematic for FIG. 3 is similar to that of FIG. 2 except that the space between electrodes of opposite polarity is filled with a porous membrane and the spacing is reduced.",
"Wastewater 30 flows into a canister filter 31 (or equivalent) to ensure that the water has no significant particle content.",
"The filtered wastewater 32 flows in the treatment unit 33 .",
"The treatment unit 33 contains an electrical series configuration of electrolysis electrodes 34 consisting of a sandwich of hollow insulating plastic positioning plates 35 and hollow porous electrolysis electrodes 34 .",
"The insulating plates can be composed of any suitable plastic such as but not limited to acrylic, polycarbonate, Teflon, or PVC.",
"The insulating plastic plates 35 serve to precisely position the electrodes 34 together, to clamp the electrodes onto the 1-mm thick membrane 36 , and electrically isolate the electrodes 34 .",
"Water is fed through holes 42 in the bottom plastic positioning plates 35 into one set of electrodes and is exhausted at the top of adjacent porous electrodes of opposite polarity.",
"Sparging air 37 is injected into the hollow electrodes 34 as needed.",
"A direct current power supply 38 applies voltage to the electrodes 34 at the first electrode plate 39 and the last electrode plate 40 .",
"The applied voltage per electrode pair (a cell) is the total applied voltage divided by the total number of electrolysis cells.",
"Ammonia gas 41 is formed on the surface of the electrodes 34 .",
"Gaseous ammonia 41 migrates into the hollow electrodes and is carried away by the sparging air 37 and water.",
"The treated wastewater 43 , having passed through the electrolysis system, exits the treatment unit 33 .",
"While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention."
] |
This application is a continuation of application Ser. No. 09/036,194, filed on Mar. 6, 1998, U.S. Pat. No. 6,096,800.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for the preparation of antimicrobial polymers by polymerization of tert-butylaminoethyl methacrylate, and the use of the antimicrobial polymers. More particularly, the invention relates to a process for the preparation of antimicrobial polymers by graft polymerization of tert-butylaminoethyl methacrylate on a substrate, and the use of the antimicrobial polymers.
2. Description of the Background
The colonization and spread of bacteria on surfaces of pipelines, containers or packaging is highly undesirable. Layers of slime often form, which allow the microbe populations to rise to extreme levels, lastingly impairing the quality of water, drinks and foodstuffs, and can even lead to decay of the goods and damage to the health of consumers.
Bacteria are to be kept away from all areas of life where hygiene is of importance. Since textiles directly contact the body, and, in particular the genital area, and are used for the care of the sick and elderly, textiles should be freed of bacteria. Bacteria should also be kept away from the surfaces of furniture and equipment in nursing wards, in particular in the intensive care and infant care sector, in hospitals, especially in rooms for medical operations, and in isolation wards for critical cases of infection, as well as in toilets.
Equipment, and surfaces of furniture and textiles are currently treated to ward against bacteria as required or also preventively with chemicals or solutions and mixtures thereof which act as disinfectants, such having a more or less broad and powerful antimicrobial action. Such chemical compositions have a nonspecific action, are often themselves toxic or irritating, or form degradation products which are unacceptable to health. Intolerances are often also found in appropriately sensitized persons. Another procedure which is used to inhibit the spread of bacteria on surfaces is to incorporate antimicrobially active substances into a matrix.
Tert-butylaminoethyl methacrylate is a commercially available monomer of methacrylate chemistry and is employed in particular as a hydrophilic monomer in copolymerizations. Thus, EP 0 290 676 describes the use of various polyacrylates and polymethacrylates as a matrix for immobilization of bactericidal quaternary ammonium compounds.
U.S. Pat. No. 3,592,805 discloses the preparation of systemic fungicides in which per halogenated acetone derivatives are reacted with methacrylate esters, such as, for example, tert-butylaminoethyl methacrylate.
U.S. Pat. No. 4,515,910 describes the use of polymers of hydrogen fluoride salts of aminomethacrylates in dental medicine. The hydrogen fluoride bonded in the polymers emerges slowly from the polymer matrix and is said to be effective against caries.
In another technical field, U.S. Pat. No. 4,532,269 discloses a terpolymer of butyl methacrylate, tributyltin methacrylate and tert-butylaminoethyl methacrylate. This polymer is used as an antimicrobial paint for ships, the hydrophilic tert-butylaminoethyl methacrylate promoting slow erosion of the polymer and in this way liberating the highly toxic tributyltin methacrylate as an antimicrobially active compound.
In these applications, the copolymer prepared with aminomethacrylates is only a matrix or carrier substance for added microbicidal active compounds, which can diffuse or migrate out of the carrier. Polymers of this type lose their action at a faster or slower rate when the necessary “minimum inhibitory concentration” (MIC) is no longer achieved on the surface.
EP 0 204 312 describes a process for the preparation of antimicrobially treated acrylonitrile fibers. The antimicrobial action is based on a protonated amine as a comonomer unit, dimethylaminoethyl methacrylate and tertbutylaminoethyl methacrylate, inter alia, being used as protonated species. However, the antimicrobial action of protonated surfaces is severely reduced after loss of the H(+) ions. A need continues to exist for an effective method of providing surfaces of objects with antimicrobial properties.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide materials which have antimicrobial properties, which contain no active compounds which can be washed out, and in which the antimicrobial action is pH-independent.
Another object of the present invention is to provide surfaces of objects and apparatus with a permanently microbicidal polymeric coating which is not attacked by solvents and physical stress and which shows no migration, and by which it is not necessary to employ additional biocidally active compounds.
Briefly, these objects and other objects of the present invention as hereinafter will become more readily apparent can be attained by a method of imparting antimicrobial activity to the surface(s) of an apparatus or article, which comprises polymerizing tert-butylaminoethyl methacrylate in the presence of the apparatus or article by which adhesion of the polymer to said surface(s) is achieved. In a preferred embodiment of the invention the tert-butylaminoethyl methacrylate monomer is graft polymerized onto the surface.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The antimicrobial polymers of the invention can be obtained by grafting polymerizing tert-butylaminoethyl methacrylate on a surface of an article or apparatus.
Suitable substrate materials include, above all, all polymeric plastics, such as, for example, polyurethanes, polyamides, polyesters, polyethers, polyether-block amides, polystyrene, polyvinyl chloride, polycarbonates, polyorganosiloxanes, polyolefins, polysulfones, polyisoprene, polychloroprene, polytetrafluoroethylene (PTFE), corresponding copolymers and blends, as well as natural and synthetic rubbers, with or without radiation-sensitive groups. The process of the invention can also be applied on the surfaces of metal, glass or wooden bodies which are painted or are otherwise coated with plastic.
The surfaces of the substrates can be activated by a number of methods before the grafting polymerization. They are expediently freed from oils, greases or other impurities beforehand in a known manner by means of a solvent.
The standard polymers can be activated by UV radiation. A suitable source of radiation is, for example, a UV-Excimer apparatus HERAEUS Noblelight, Hanau, Germany. However, mercury vapor lamps are also suitable for activation of the substrate if they emit considerable proportions of radiation in the ranges mentioned. The exposure time generally ranges from 0.1 second to 20 minutes, preferably 1 second to 10 minutes.
The activation of the standard polymers with UV radiation can furthermore be carried out with an additional photosensitizer. Suitable such photosensitizers include, for example, benzophenone, as such are applied to the surface of the substrate and irradiated. In this context, irradiation can be conducted with a mercury vapor lamp using exposure times of 0.1 second to 20 minutes, preferably 1 second to 10 minutes.
According to the invention, the activation can also be achieved by a high frequency or microwave plasma (Hexagon, Technics Plasma, 85551 Kirchheim, Germany) in air or a nitrogen or argon atmosphere. The exposure times generally range from 30 seconds to 30 minutes, preferably 2 to 10 minutes.
The energy output of laboratory apparatus is between 100 and 500 W, preferably between 200 and 300 W.
Corona apparatus (SOFTAL, Hamburg, Germany) can furthermore be used for the activation. In this case, the exposure times are, as a rule, 1 to 10 minutes, preferably 1 to 60 seconds.
Activation by electron beams or y-rays, for example, from a cobalt-60 source) and ozonization allow short exposure times which are generally range from 0.1 to 60 seconds.
The flaming of surfaces likewise leads to activation of the surfaces. Suitable apparatus, in particular those having a barrier flame front, can be constructed in a simple manner or obtained, for example, from ARCOTEC, 71297 M{umlaut over (n)}sheim, Germany. The apparatus can employ hydrocarbons or hydrogen as the combustible gas. In all cases, harmful overheating of the substrates must be avoided, which is easily achieved by intimate contact with a cooled metal surface on the substrate surface facing away from the flaming side. Activation by flaming is accordingly limited to relatively thin, flat substrates. The exposure times generally range from 0.1 second to 1 minute, preferably 0.5 to 2 seconds. The flames without exception are nonluminous and the distances between the substrate surfaces and the outer flame front ranges from 0.2 to 5 cm, preferably 0.5 to 2 cm.
The substrate surfaces activated in this way are coated with tertbutylaminoethyl methacrylate, if appropriate in solution, by known methods, such as by dipping, spraying or brushing. Suitable solvents have proved to be water and water/ethanol mixtures, although other solvents can also be used if they have a sufficient dissolving power for tert-butylaminoethyl methacrylate and wet the substrate surfaces thoroughly. Solutions having monomer contents of 1 to 10% by weight, for example about 5% by weight, have proved suitable in practice and in general give continuous coatings which cover the substrate surface and have coating thicknesses which can be more than 0.1 μm in one pass.
The grafting copolymerization of the monomer applied to the activated surfaces is expediently effected by short wavelength radiation in the visible range or in the long wavelength segment of the UV range of electromagnetic radiation. The radiation of a UV-Excimer of wavelengths 250 to 500 nm, preferably 290 to 320 nm, for example, is particularly suitable. Mercury vapor lamps are also suitable here if they emit considerable amounts of radiation in the ranges mentioned. The exposure times generally range from 10 seconds to 30 minutes, preferably 2 to 15 minutes.
Poly-tert-butylaminoethyl methacrylate also shows intrinsic microbicidal properties without grafting to a substrate surface.
One possible embodiment of the present invention comprises a procedure in which the polymerization of tert-butylaminoethyl methacrylate can be carried out on a substrate.
An antimicrobial polymer can furthermore be prepared by polymerization of tert-butylaminoethyl methacrylate by known processes.
In the process of the invention, the polymer of tert-butylaminoethyl methacrylate can also be applied to the substrate in solution.
Suitable solvents include, for example, water, ethanol, methanol, methyl ethyl ketone, diethyl ether, dioxane, hexane, heptane, benzene, toluene, chloroform, methylene chloride, tetrahydrofuran and acetonitrile.
The solution of the polymer obtained by polymerization of tert-butylaminoethyl methacrylate is applied to the standard polymers, for example, by dipping, spraying or painting.
If the polymer is produced directly on the substrate surface without grafting, suitable initiators are added in order to promote polymerization. Initiators which can be used include, inter alia, azonitriles, alkyl peroxides, hydroperoxides, acyl peroxides, peroxoketones, peresters, peroxocarbonates, peroxodisulfate, persulfate and all the customary photoinitiators, such as, for example, acetophenones and benzophenone.
The initiation of the polymerization can be carried out by means of heat or by electromagnetic radiation, such as, for example, UV light or γ-radiation.
The present antimicrobial polymers can be used for the production of products such as medical articles or hygienic articles.
Medical articles produced by the process of the invention include, for example, catheters, blood bags, drainages, guide wires and surgical instruments.
The process according to the invention can furthermore be employed for the production of hygienic articles, such as, for example, toothbrushes, toilet seats, combs and packaging materials.
Having now generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.
EXAMPLE 1
A 27 g amount of tert-butylaminoethyl methacrylate and 150 ml of ethanol is heated to 65° C. under an inert gas. When the temperature is reached, 0.37 g of azobisisobutyronitrile, dissolved in 10 ml of methyl ethyl ketone, is added. At the end of 24 hours, the reaction is ended by stirring the mixture into 11 of a water/ice mixture. The reaction product is removed by filtration and washed with 300 ml of n-hexane. The product is then distributed over several Soxhlets and extracted with water for 24 hours, and is then dried at 50° C. in vacuo for 12 hours.
Example 2
A 4 g amount of poly-tert-butylaminoethyl methacrylate from Example 1 is dissolved in 40 ml of tetrahydrofuran. A polyamide 12 film is immersed in this solution for 5 seconds, removed from the solution for 10 seconds and them immersed again for 5 seconds, so that a uniform film of poly-tert-butylaminoethyl methacrylate has formed on the polyamide film after subsequent drying at room temperature under normal pressure. The film is then dried at 50° C. in vacuo for 24 hours. The film is subsequently extracted in water at 30° C. 5 times for 6 hours and then dried at 50° C. for 12 hours.
Example 3
A 4 g amount of poly-tert-butylaminoethyl methacrylate from Example 1 is dissolved in 40 ml of tetrahydrofuran. A polyvinyl chloride film is immersed in this solution for 2 seconds, removed from the solution for 10 seconds and then immersed again for 2 seconds, so that a uniform film of poly-tert-butylaminoethyl methacrylate has formed on the polyvinyl chloride film after subsequent drying at room temperature under normal pressure. The film is then dried at 50° C. in vacuo for 24 hours. The film is subsequently extracted in water at 30° C. 5 times for 6 hours and then dried at 50° C. for 12 hours.
Example 4
A polyamide 12 film is exposed to the 172 nm radiation of an Excimer radiation source manufactured by Heraeus for 2 minutes under a pressure of 1 mbar. The film activated in this way is laid and fixed in an irradiation reactor under an inert gas. The film is then covered with a layer of 20 ml of a mixture of 3 g of tert-butylaminoethyl methacrylate and 97 g of methanol in a countercurrent flow of inert gas. The irradiation chamber is closed and placed at a distance of 10 cm underneath an Excimer radiation unit manufactured by Heraeus, which has an emission of wavelength 308 nm. The irradiation is started, and the exposure time is 15 minutes. The film is removed and rinsed off with 30 ml of methanol. The film is then dried at 50° C. in vacuo for 12 hours. The film is subsequently extracted in water at 30° C. 5 times for 6 hours and then dried at 50° C. for 12 hours.
Measurement of Bactericidal Action
The bactericidal action of coated plastics was measured as follows:
A 100 μl of a cell suspension of Klebsiella pneumoniae was placed on a piece of film 2×2 cm in size. The bacteria were suspended in PBS buffer (phosphate-buffered saline); the cell concentration was 10 5 cells per ml of buffer solution. This drop was incubated for up to 3 hours. In order to prevent any drying out of the applied drop, the piece of film was laid in a polystyrene Petri dish wetted with 1 ml of water. After the end of the contact time, the 100 μl were taken up with an Eppendorf tip and diluted in 1.9 ml of sterile PBS. A 0.2 ml amount of this solution was plated out on nutrient agar. The rate of inactivation was calculated from the number of colonies which had grown.
Checking the Resistance of the Coatings
Before the measurement of the bactericidal action, the coated films were subjected to the following pretreatments:
A: Washing in boiling water for 10 minutes
B: Washing in 96% strength ethanolic solution for 10 minutes
C: Washing in warm water at 25° C. under ultrasonic treatment for 10 minutes
D: No pretreatment
The results of the measurements, taking into account the particular pretreatment are listed in Table 1.
TABLE 1
Rate of Inactivation
Example
A
B
C
D
2
4%
<10%
56%
99.9%
3
5%
<10%
54%
99.9%
4
99.9%
99.9%
99.9%
99.9%
After thermal, chemical or mechanical pretreatment, the antimicrobial layers produced by grafting of a substrate surface continue to show virtually complete inactivation of the bacteria applied. The physically adhered layers are less stable to the pretreatment of methods A, B and C.
In addition to the microbicidal activity against cells of Klebsiella pneumoniae which has been described above, all the coated films also showed a microbicidal action against cells of Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Rhizopus oryzae, Candida tropicalis and Tetrahymena pyriformis. The rate of inactivation after treatment method D was also more than 99% in these cases.
The disclosure of priority German Application No. 197 09 076.1 having a filing date of Mar. 6, 1997 is hereby incorporated by reference into the application.
Obviously, numerous modifications and variations of the present invention are permissible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. | Antimicrobial activity is imparted to the surface(s) of an apparatus or article by polymerizing tert-butylaminoethyl methacrylate in the presence of the apparatus or article by which adhesion of the polymer to the surface(s) is achieved. In a preferred embodiment of the invention the antimicrobial monomer is graft polymerized on the surface(s). | Summarize the patent document, focusing on the invention's functionality and advantages. | [
"This application is a continuation of application Ser.",
"No. 09/036,194, filed on Mar. 6, 1998, U.S. Pat. No. 6,096,800.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present invention relates to a process for the preparation of antimicrobial polymers by polymerization of tert-butylaminoethyl methacrylate, and the use of the antimicrobial polymers.",
"More particularly, the invention relates to a process for the preparation of antimicrobial polymers by graft polymerization of tert-butylaminoethyl methacrylate on a substrate, and the use of the antimicrobial polymers.",
"Description of the Background The colonization and spread of bacteria on surfaces of pipelines, containers or packaging is highly undesirable.",
"Layers of slime often form, which allow the microbe populations to rise to extreme levels, lastingly impairing the quality of water, drinks and foodstuffs, and can even lead to decay of the goods and damage to the health of consumers.",
"Bacteria are to be kept away from all areas of life where hygiene is of importance.",
"Since textiles directly contact the body, and, in particular the genital area, and are used for the care of the sick and elderly, textiles should be freed of bacteria.",
"Bacteria should also be kept away from the surfaces of furniture and equipment in nursing wards, in particular in the intensive care and infant care sector, in hospitals, especially in rooms for medical operations, and in isolation wards for critical cases of infection, as well as in toilets.",
"Equipment, and surfaces of furniture and textiles are currently treated to ward against bacteria as required or also preventively with chemicals or solutions and mixtures thereof which act as disinfectants, such having a more or less broad and powerful antimicrobial action.",
"Such chemical compositions have a nonspecific action, are often themselves toxic or irritating, or form degradation products which are unacceptable to health.",
"Intolerances are often also found in appropriately sensitized persons.",
"Another procedure which is used to inhibit the spread of bacteria on surfaces is to incorporate antimicrobially active substances into a matrix.",
"Tert-butylaminoethyl methacrylate is a commercially available monomer of methacrylate chemistry and is employed in particular as a hydrophilic monomer in copolymerizations.",
"Thus, EP 0 290 676 describes the use of various polyacrylates and polymethacrylates as a matrix for immobilization of bactericidal quaternary ammonium compounds.",
"U.S. Pat. No. 3,592,805 discloses the preparation of systemic fungicides in which per halogenated acetone derivatives are reacted with methacrylate esters, such as, for example, tert-butylaminoethyl methacrylate.",
"U.S. Pat. No. 4,515,910 describes the use of polymers of hydrogen fluoride salts of aminomethacrylates in dental medicine.",
"The hydrogen fluoride bonded in the polymers emerges slowly from the polymer matrix and is said to be effective against caries.",
"In another technical field, U.S. Pat. No. 4,532,269 discloses a terpolymer of butyl methacrylate, tributyltin methacrylate and tert-butylaminoethyl methacrylate.",
"This polymer is used as an antimicrobial paint for ships, the hydrophilic tert-butylaminoethyl methacrylate promoting slow erosion of the polymer and in this way liberating the highly toxic tributyltin methacrylate as an antimicrobially active compound.",
"In these applications, the copolymer prepared with aminomethacrylates is only a matrix or carrier substance for added microbicidal active compounds, which can diffuse or migrate out of the carrier.",
"Polymers of this type lose their action at a faster or slower rate when the necessary “minimum inhibitory concentration”",
"(MIC) is no longer achieved on the surface.",
"EP 0 204 312 describes a process for the preparation of antimicrobially treated acrylonitrile fibers.",
"The antimicrobial action is based on a protonated amine as a comonomer unit, dimethylaminoethyl methacrylate and tertbutylaminoethyl methacrylate, inter alia, being used as protonated species.",
"However, the antimicrobial action of protonated surfaces is severely reduced after loss of the H(+) ions.",
"A need continues to exist for an effective method of providing surfaces of objects with antimicrobial properties.",
"SUMMARY OF THE INVENTION Accordingly, one object of the present invention is to provide materials which have antimicrobial properties, which contain no active compounds which can be washed out, and in which the antimicrobial action is pH-independent.",
"Another object of the present invention is to provide surfaces of objects and apparatus with a permanently microbicidal polymeric coating which is not attacked by solvents and physical stress and which shows no migration, and by which it is not necessary to employ additional biocidally active compounds.",
"Briefly, these objects and other objects of the present invention as hereinafter will become more readily apparent can be attained by a method of imparting antimicrobial activity to the surface(s) of an apparatus or article, which comprises polymerizing tert-butylaminoethyl methacrylate in the presence of the apparatus or article by which adhesion of the polymer to said surface(s) is achieved.",
"In a preferred embodiment of the invention the tert-butylaminoethyl methacrylate monomer is graft polymerized onto the surface.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The antimicrobial polymers of the invention can be obtained by grafting polymerizing tert-butylaminoethyl methacrylate on a surface of an article or apparatus.",
"Suitable substrate materials include, above all, all polymeric plastics, such as, for example, polyurethanes, polyamides, polyesters, polyethers, polyether-block amides, polystyrene, polyvinyl chloride, polycarbonates, polyorganosiloxanes, polyolefins, polysulfones, polyisoprene, polychloroprene, polytetrafluoroethylene (PTFE), corresponding copolymers and blends, as well as natural and synthetic rubbers, with or without radiation-sensitive groups.",
"The process of the invention can also be applied on the surfaces of metal, glass or wooden bodies which are painted or are otherwise coated with plastic.",
"The surfaces of the substrates can be activated by a number of methods before the grafting polymerization.",
"They are expediently freed from oils, greases or other impurities beforehand in a known manner by means of a solvent.",
"The standard polymers can be activated by UV radiation.",
"A suitable source of radiation is, for example, a UV-Excimer apparatus HERAEUS Noblelight, Hanau, Germany.",
"However, mercury vapor lamps are also suitable for activation of the substrate if they emit considerable proportions of radiation in the ranges mentioned.",
"The exposure time generally ranges from 0.1 second to 20 minutes, preferably 1 second to 10 minutes.",
"The activation of the standard polymers with UV radiation can furthermore be carried out with an additional photosensitizer.",
"Suitable such photosensitizers include, for example, benzophenone, as such are applied to the surface of the substrate and irradiated.",
"In this context, irradiation can be conducted with a mercury vapor lamp using exposure times of 0.1 second to 20 minutes, preferably 1 second to 10 minutes.",
"According to the invention, the activation can also be achieved by a high frequency or microwave plasma (Hexagon, Technics Plasma, 85551 Kirchheim, Germany) in air or a nitrogen or argon atmosphere.",
"The exposure times generally range from 30 seconds to 30 minutes, preferably 2 to 10 minutes.",
"The energy output of laboratory apparatus is between 100 and 500 W, preferably between 200 and 300 W. Corona apparatus (SOFTAL, Hamburg, Germany) can furthermore be used for the activation.",
"In this case, the exposure times are, as a rule, 1 to 10 minutes, preferably 1 to 60 seconds.",
"Activation by electron beams or y-rays, for example, from a cobalt-60 source) and ozonization allow short exposure times which are generally range from 0.1 to 60 seconds.",
"The flaming of surfaces likewise leads to activation of the surfaces.",
"Suitable apparatus, in particular those having a barrier flame front, can be constructed in a simple manner or obtained, for example, from ARCOTEC, 71297 M{umlaut over (n)}sheim, Germany.",
"The apparatus can employ hydrocarbons or hydrogen as the combustible gas.",
"In all cases, harmful overheating of the substrates must be avoided, which is easily achieved by intimate contact with a cooled metal surface on the substrate surface facing away from the flaming side.",
"Activation by flaming is accordingly limited to relatively thin, flat substrates.",
"The exposure times generally range from 0.1 second to 1 minute, preferably 0.5 to 2 seconds.",
"The flames without exception are nonluminous and the distances between the substrate surfaces and the outer flame front ranges from 0.2 to 5 cm, preferably 0.5 to 2 cm.",
"The substrate surfaces activated in this way are coated with tertbutylaminoethyl methacrylate, if appropriate in solution, by known methods, such as by dipping, spraying or brushing.",
"Suitable solvents have proved to be water and water/ethanol mixtures, although other solvents can also be used if they have a sufficient dissolving power for tert-butylaminoethyl methacrylate and wet the substrate surfaces thoroughly.",
"Solutions having monomer contents of 1 to 10% by weight, for example about 5% by weight, have proved suitable in practice and in general give continuous coatings which cover the substrate surface and have coating thicknesses which can be more than 0.1 μm in one pass.",
"The grafting copolymerization of the monomer applied to the activated surfaces is expediently effected by short wavelength radiation in the visible range or in the long wavelength segment of the UV range of electromagnetic radiation.",
"The radiation of a UV-Excimer of wavelengths 250 to 500 nm, preferably 290 to 320 nm, for example, is particularly suitable.",
"Mercury vapor lamps are also suitable here if they emit considerable amounts of radiation in the ranges mentioned.",
"The exposure times generally range from 10 seconds to 30 minutes, preferably 2 to 15 minutes.",
"Poly-tert-butylaminoethyl methacrylate also shows intrinsic microbicidal properties without grafting to a substrate surface.",
"One possible embodiment of the present invention comprises a procedure in which the polymerization of tert-butylaminoethyl methacrylate can be carried out on a substrate.",
"An antimicrobial polymer can furthermore be prepared by polymerization of tert-butylaminoethyl methacrylate by known processes.",
"In the process of the invention, the polymer of tert-butylaminoethyl methacrylate can also be applied to the substrate in solution.",
"Suitable solvents include, for example, water, ethanol, methanol, methyl ethyl ketone, diethyl ether, dioxane, hexane, heptane, benzene, toluene, chloroform, methylene chloride, tetrahydrofuran and acetonitrile.",
"The solution of the polymer obtained by polymerization of tert-butylaminoethyl methacrylate is applied to the standard polymers, for example, by dipping, spraying or painting.",
"If the polymer is produced directly on the substrate surface without grafting, suitable initiators are added in order to promote polymerization.",
"Initiators which can be used include, inter alia, azonitriles, alkyl peroxides, hydroperoxides, acyl peroxides, peroxoketones, peresters, peroxocarbonates, peroxodisulfate, persulfate and all the customary photoinitiators, such as, for example, acetophenones and benzophenone.",
"The initiation of the polymerization can be carried out by means of heat or by electromagnetic radiation, such as, for example, UV light or γ-radiation.",
"The present antimicrobial polymers can be used for the production of products such as medical articles or hygienic articles.",
"Medical articles produced by the process of the invention include, for example, catheters, blood bags, drainages, guide wires and surgical instruments.",
"The process according to the invention can furthermore be employed for the production of hygienic articles, such as, for example, toothbrushes, toilet seats, combs and packaging materials.",
"Having now generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.",
"EXAMPLE 1 A 27 g amount of tert-butylaminoethyl methacrylate and 150 ml of ethanol is heated to 65° C. under an inert gas.",
"When the temperature is reached, 0.37 g of azobisisobutyronitrile, dissolved in 10 ml of methyl ethyl ketone, is added.",
"At the end of 24 hours, the reaction is ended by stirring the mixture into 11 of a water/ice mixture.",
"The reaction product is removed by filtration and washed with 300 ml of n-hexane.",
"The product is then distributed over several Soxhlets and extracted with water for 24 hours, and is then dried at 50° C. in vacuo for 12 hours.",
"Example 2 A 4 g amount of poly-tert-butylaminoethyl methacrylate from Example 1 is dissolved in 40 ml of tetrahydrofuran.",
"A polyamide 12 film is immersed in this solution for 5 seconds, removed from the solution for 10 seconds and them immersed again for 5 seconds, so that a uniform film of poly-tert-butylaminoethyl methacrylate has formed on the polyamide film after subsequent drying at room temperature under normal pressure.",
"The film is then dried at 50° C. in vacuo for 24 hours.",
"The film is subsequently extracted in water at 30° C. 5 times for 6 hours and then dried at 50° C. for 12 hours.",
"Example 3 A 4 g amount of poly-tert-butylaminoethyl methacrylate from Example 1 is dissolved in 40 ml of tetrahydrofuran.",
"A polyvinyl chloride film is immersed in this solution for 2 seconds, removed from the solution for 10 seconds and then immersed again for 2 seconds, so that a uniform film of poly-tert-butylaminoethyl methacrylate has formed on the polyvinyl chloride film after subsequent drying at room temperature under normal pressure.",
"The film is then dried at 50° C. in vacuo for 24 hours.",
"The film is subsequently extracted in water at 30° C. 5 times for 6 hours and then dried at 50° C. for 12 hours.",
"Example 4 A polyamide 12 film is exposed to the 172 nm radiation of an Excimer radiation source manufactured by Heraeus for 2 minutes under a pressure of 1 mbar.",
"The film activated in this way is laid and fixed in an irradiation reactor under an inert gas.",
"The film is then covered with a layer of 20 ml of a mixture of 3 g of tert-butylaminoethyl methacrylate and 97 g of methanol in a countercurrent flow of inert gas.",
"The irradiation chamber is closed and placed at a distance of 10 cm underneath an Excimer radiation unit manufactured by Heraeus, which has an emission of wavelength 308 nm.",
"The irradiation is started, and the exposure time is 15 minutes.",
"The film is removed and rinsed off with 30 ml of methanol.",
"The film is then dried at 50° C. in vacuo for 12 hours.",
"The film is subsequently extracted in water at 30° C. 5 times for 6 hours and then dried at 50° C. for 12 hours.",
"Measurement of Bactericidal Action The bactericidal action of coated plastics was measured as follows: A 100 μl of a cell suspension of Klebsiella pneumoniae was placed on a piece of film 2×2 cm in size.",
"The bacteria were suspended in PBS buffer (phosphate-buffered saline);",
"the cell concentration was 10 5 cells per ml of buffer solution.",
"This drop was incubated for up to 3 hours.",
"In order to prevent any drying out of the applied drop, the piece of film was laid in a polystyrene Petri dish wetted with 1 ml of water.",
"After the end of the contact time, the 100 μl were taken up with an Eppendorf tip and diluted in 1.9 ml of sterile PBS.",
"A 0.2 ml amount of this solution was plated out on nutrient agar.",
"The rate of inactivation was calculated from the number of colonies which had grown.",
"Checking the Resistance of the Coatings Before the measurement of the bactericidal action, the coated films were subjected to the following pretreatments: A: Washing in boiling water for 10 minutes B: Washing in 96% strength ethanolic solution for 10 minutes C: Washing in warm water at 25° C. under ultrasonic treatment for 10 minutes D: No pretreatment The results of the measurements, taking into account the particular pretreatment are listed in Table 1.",
"TABLE 1 Rate of Inactivation Example A B C D 2 4% <10% 56% 99.9% 3 5% <10% 54% 99.9% 4 99.9% 99.9% 99.9% 99.9% After thermal, chemical or mechanical pretreatment, the antimicrobial layers produced by grafting of a substrate surface continue to show virtually complete inactivation of the bacteria applied.",
"The physically adhered layers are less stable to the pretreatment of methods A, B and C. In addition to the microbicidal activity against cells of Klebsiella pneumoniae which has been described above, all the coated films also showed a microbicidal action against cells of Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Rhizopus oryzae, Candida tropicalis and Tetrahymena pyriformis.",
"The rate of inactivation after treatment method D was also more than 99% in these cases.",
"The disclosure of priority German Application No. 197 09 076.1 having a filing date of Mar. 6, 1997 is hereby incorporated by reference into the application.",
"Obviously, numerous modifications and variations of the present invention are permissible in light of the above teachings.",
"It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein."
] |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of Applicant's co-pending U.S. patent application Ser. No. 14/076,288 filed Nov. 11, 2013, which claims the benefit of priority from U.S. Provisional Patent Application No. 61/724,992, filed Nov. 11, 2012, the contents of which are incorporated by reference in their entirety.
FIELD OF THE INVENTION
[0002] The disclosure herein relates to providing personalized settings for sharing viewed channels of a social media user. In particular, the disclosure relates to the ability of providing members of a social group, the functionality to decide if usage of a specific channel is recorded and/or accessible to other online social network members.
BACKGROUND OF THE INVENTION
[0003] Television sets have become commonplace in homes, businesses and institutions offering diversified digital content, with viewing considered as a passive and relaxing experience, limited to the place itself.
[0004] During the last few years, with advancement of technology, various developments have been made to provide television services on a social basis taking advantage of the relationship between individuals, connecting users watching public television content in different locations. The vast amount of new electronic display devices adds to social television the concept of shared-viewing trends in creating a shift in television viewing from passive to active experience.
[0005] Social television introduced advanced technology which combines communication and social environment in the context of watching digital content, enabling the most common social television activity of watching digital content with others, allowing instant sharing of favorite digital media content with a social group. Such systems may, for example, provide text chat, indicating the presence and context consciousness, integrate voice communication, viewing of recommendations, ratings or video-conferencing related to viewing digital content either directly on screen or by using supplementary devices.
[0006] Furthermore, the media viewing experience is turning richer with video content becoming available on increasingly diverse devices such as television, personal computers, tablets, mobile communication devices, telephones, hand held devices and the like. In parallel, the social environment is changing, taking advantage of new emerging technologies and yielding a whole new world of experiences. Television broadcasting networks continue to deliver digital content in diverse areas of interest, answering different tastes and flavors. Combining the digital media, specifically the television as a platform, with the social environment increases the demand for sharing digital content and views.
[0007] Television is a wide reaching vehicle and a highly significant player in the digital media content domain. Recent studies of consumer behavior and television measurements (eMarketer—Digital Intelligence, Nielsen) claim that 99% of American households watch television on a regular basis, with the average adult spending more time watching television than surfing the interest. The report reveals that in 2010, the average adult spent about four and half hours per day watching television, compared to an average of just two and a half hours per day spent online.
[0008] Additionally, the percentage of American homes having at least one television set is reaching 99%, with two thirds of them owning at least three sets. These numbers highlight the fact that television is still a most widespread and premier entertainment platform.
SUMMARY OF THE INVENTION
[0009] It is an advantage of the current disclosure that an additional mode of operation is provided to allow controlling the exposure of media channel information, specifically limiting access to current usage or recorded history data, with minimal impact on user privacy.
[0010] While social television becomes more popular the exposure of media channel information may go beyond user expectations. Users may want to control what is exposed to others and to what extent, specifically related to information of the channel currently viewed and more generally, control the exposure of the current usage or recorded data history of accessing all or specific media channels. Such user control may provide functionality of blocking others completely or partially from accessing such recorded data.
[0011] Additionally, such control functionality may provide abilities of blocking access to currently viewed channels, removing the existing recorded data history, ceasing recording of such data or providing functionality of setting permissions for specific users or user groups of different social spaces.
[0012] In various embodiments of the disclosure, one or more tasks as described herein may be performed by a data processor, such as a computing platform or distributed computing system for executing a plurality of instructions. Optionally, the data processor includes or accesses a volatile memory for storing instructions, data or the like. Additionally or alternatively, the data processor may access a non-volatile storage, for example, a magnetic hard-disk, flash-drive, removable media or the like, for storing instructions and/or data.
[0013] Optionally, a network connection may additionally or alternatively be provided. User interface devices may be provided such as visual displays, audio output devices, tactile outputs and the like. Furthermore, as required, user input devices may be provided such as keyboards, cameras, microphones, accelerometers, motion detectors or pointing devices such as mice, roller balls, touch pads, touch sensitive screens or the like.
[0014] Optionally, a system may include a client terminal such as a set-top-box, mobile communication device or the like, which is operable to receive user defined preferences, monitor available media content and to control the input media renderer accordingly.
[0015] A set-top box (STB), referred to herein, may comprise an information appliance that connects to a television set and an external source of signal, decoding that signal into content that can be presented on a television unit or other display device.
[0016] Optionally, the media renderer may be selected from a group consisting of: televisions, media players, tablet computers, computers, digital picture frames, hand held devices and the like. Where required, the client terminal may be selected from a group consisting of: set-top-boxes, mobile communication devices, remote control devices and telephones and the like.
[0017] The interaction with the user may be applied via a friendly user interface that may be driven by a management module. Additionally, it may work in different possible architectures, for example using a network based approach to allow remote activities, or a locally managed approach.
[0018] In any of the above possible system architectures, the interests of a viewer in such a media socializing environment, may be reflected through a user preference profile, for example. User preference profile may serve for storing user preferences, privacy data, social groups, social spaces and the like.
[0019] User groups and social spaces may be classified, for example, according to various preferences, tastes or interests of the user interacting and communicating in such a social environment. Any member of a user space, may be authorized, by assigning permission to view shared recorded content. This open access to shared data may be limited or narrowed by user profile definitions or may partially exclude specific user classified groups from viewing a part of the user social space data, by limiting access to current usage or recorded data history of media channels accessed.
[0020] Optionally, the user preference profile may be created and configured manually or automatically. Manual configuration may designate categories of interests and the like, while automatic configuration may require machine learning algorithms or statistical analysis tools to deal with its complexity and high dimensionality.
[0021] According to one aspect of the presently disclosed subject matter, there is provided a method of sharing usage data of multimedia content, the method comprising:
[0022] providing a set of media channels;
[0023] providing access, to one or more pre-selected remote users, to usage data regarding consumption of the multimedia content; and
[0024] selectively restricting access of at least a portion of the usage data to at least a portion of the remote users.
[0025] The method may further comprise:
[0026] defining one or more remote user categories;
[0027] assigning at least some of the pre-selected remote users to the remote user categories; and
[0028] defining, for at least one or more of the remote user categories, access restrictions of at least a portion of the usage data for remote users assigned to the one or more remote user categories.
[0029] The method may further comprise:
[0030] defining one or more media categories;
[0031] assigning at least some of the media channels to the media categories; and
[0032] defining, for at least one or more of the media categories, access restrictions of at least a portion of the usage data for media channels assigned to the one or more media categories.
[0033] The method may further comprise:
[0034] defining one or more remote user categories and one or more media categories;
[0035] assigning at least some of the pre-selected remote users to the remote user categories, and at least some of the media channels to the media categories; and
[0036] defining, for at least one or more combinations of one of the remote user categories and one of the media categories, access restrictions of at least a portion of the usage data relating to media channels assigned to the media category, for remote users assigned to the remote user category.
[0037] The usage data may be selected from at least one of the group consisting of viewing history, recording history, user comments, and combinations thereof.
[0038] The selectively restricting access may be based on at least one of a time schedule and programming. For example, a user may selectively restrict access to at least some usage data for viewing and/or recording during a predefined time, irrespective of programming, channel, etc., thereby basing it on a time schedule. Additionally or alternatively, a user may selectively restrict access to at least some usage data relating to a particular program, irrespective of scheduling or of which media channel it appears on, thereby basing it on programming.
[0039] According to another aspect of the presently disclosed subject matter, there is provided a computer implemented method for sharing usage data of multimedia content, the method comprising at least one processor executing instructions to perform the following operations:
[0040] providing a set of media channels;
[0041] providing access, to one or more pre-selected remote users, to usage data regarding consumption of the multimedia content; and
[0042] selectively restricting access of at least a portion of the usage data to at least a portion of the remote users.
[0043] The computer implemented method may further comprise:
[0044] defining one or more remote user categories;
[0045] assigning at least some of the pre-selected remote users to the remote user categories; and
[0046] defining, for at least one or more of the remote user categories, access restrictions of at least a portion of the usage data for remote users assigned to the one or more remote user categories.
[0047] The computer implemented method may further comprise:
[0048] defining one or more media categories;
[0049] assigning at least some of the media channels to the media categories; and
[0050] defining, for at least one or more of the media categories, access restrictions of at least a portion of the usage data for media channels assigned to the one or more media categories.
[0051] The computer implemented method may further comprise:
[0052] defining one or more remote user categories and one or more media categories;
[0053] assigning at least some of the pre-selected remote users to the remote user categories, and at least some of the media channels to the media categories; and
[0054] defining, for at least one or more combinations of one of the remote user categories and one of the media categories, access restrictions of at least a portion of the usage data relating to media channels assigned to the media category, for remote users assigned to the remote user category.
[0055] The usage data may be selected from at least one of the group consisting of: viewing history, recording history, user comments and combinations thereof.
[0056] The selectively restricting access may be based on at least one of a time schedule and programming.
[0057] According to a further aspect of the presently disclosed subject matter, there is provided a system for sharing usage data of multimedia content comprising a communication network in communication with a plurality of client terminals, the communication network comprising at least one central unit processor operable to:
[0058] provide access, to one or more client terminals, to usage data regarding consumption of the multimedia content; and
[0059] selectively restrict access of at least a portion of the usage data to at least a portion of the client terminals.
[0060] The central processing unit may be further operable to:
[0061] define one or more remote user categories;
[0062] assign at least some of the pre-selected remote users to the remote user categories; and
[0063] define, for at least one or more of the remote user categories, access restrictions of at least a portion of the usage data for remote users assigned to the one or more remote user categories.
[0064] The central processing unit may be further operable to:
[0065] define one or more media categories;
[0066] assign at least some of the media channels to the media categories; and
[0067] define, for at least one or more of the media categories, access restrictions of at least a portion of the usage data for media channels assigned to the one or more media categories.
[0068] The central processing unit may be further operable to:
[0069] define one or more remote user categories and one or more media categories;
[0070] assign at least some of the pre-selected remote users to the remote user categories, and at least some of the media channels to the media categories; and
[0071] define, for at least one or more combinations of one of the remote user categories and one of the media categories, access restrictions of at least a portion of the usage data relating to media channels assigned to the media category, for remote users assigned to the remote user category.
[0072] The usage data may be selected from at least one of the group consisting of: viewing history, recording history, user comments and combinations thereof.
[0073] The selectively restricting access may be based on one or more of a time schedule and programming.
BRIEF DESCRIPTION OF THE DRAWINGS
[0074] For a better understanding of the embodiments and to show how it may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings.
[0075] With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of selected embodiments only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects. In this regard, no attempt is made to show structural details in more detail than is necessary for a fundamental understanding; the description taken with the drawings making apparent to those skilled in the art how the various selected embodiments may be put into practice. In the accompanying drawings:
[0076] FIG. 1 is a block diagram representing one possible configuration of selected elements of a system for content based control of a media renderer with local processing;
[0077] FIG. 2 is a block diagram representing another possible configuration of a network-based distributed system for content based control of a media renderer with central processing and
[0078] FIG. 3 is a flowchart representing possible selected actions of a method for limiting access to current usage or recorded history data of a media channel in a social TV or other media environment.
[0079] FIG. 4 is a flowchart representing possible selected actions of a method for limiting access to current usage or recorded history data of an assigned media channel category in a social TV or other media environment.
[0080] FIGS. 5A-5C are a set of tables representing a possible assignment of privacy settings to media channels in the context of limiting access to media channel data in a social TV or other media environment.
[0081] FIG. 6 is a table representing a possible assignment of privacy settings to media channels for providing personalized access permission to media channel data in a social TV or other media environment.
DETAILED DESCRIPTION OF THE INVENTION
[0082] With reference to FIG. 1 , a block diagram is shown representing the major components of one possible configuration of selected elements of a system 100 for content based control of a media renderer 200 , with functionality of managing social interactivity in media viewing environment, locally processed and managed. The system 100 includes a client terminal 120 in communication with a media content provider 140 and connected to the media renderer 200 via a communication channel 160 . The client terminal 120 includes a processor 126 and may include additional components such as a controller 128 , a user interface 122 , and a media monitor 124 .
[0083] Optionally the user interface 122 of the client terminal 120 may be configured to allow a media consumer 110 to set preferences used by the system 100 to select control signals sent to the media renderer 200 . Various user interfaces 122 configured to facilitate inputting data to the client terminal 120 by the user 110 are known in the art, such as keyboards, touch screens, remote controls, pointing devices, etc. Optionally, the media renderer 200 may serve as at least part of the user interface 122 , for example by providing an output screen and/or an input device.
[0084] The processor 126 of the content-based control system 100 is operable to receive media content data from the media monitor 124 , and to record a user profile. The user profile may contain data related, .e.g, to media content accessed, and/or other relevant information.
[0085] The controller 128 may select control signals which it sends to the media renderer 200 .
[0086] It is noted that the media renderer may comprise a plurality of connector ports 220 a, 220 b, 220 c which may be connected to a number of media sources. For example, a first port 220 a may be connected to the client terminal 120 ; a second port 220 b may be connected to the media content provider 140 and a third port 220 c may be connected to a secondary media content provider 240 .
[0087] The management of privacy data, categorization of media channels or user groups, and current usage or recorded history data of accessing a media channel, may be controlled by the user viewing profile, for example, generated by a software package running on the client terminal processor 126 . Such a profile may reflect the categories and preferences of viewing throughout the day or over longer time periods. This viewing profile may be stored locally or may be sent to the media content provider for remote storage.
[0088] In some embodiments, a media stream may be accessed directly by the media renderer 220 , for example via the second input port 220 b. It will be appreciated that where the client terminal 120 is connected to the media renderer 200 via the first port 220 a, it will not have control over content accessed via the second input port 220 b.
[0089] By way of illustration only, control signals may use the Consumer Electronics Control (CEC) feature available for example with HDMI connections or the like. The CEC feature may allow a controller 128 to command and control the media renderer 200 by sending control signals via the client terminal 120 . For example, CEC Routing Control allows a user to control the switching of signal sources between input channels.
[0090] Where required, the controller 128 may be operable to send control signals switching the input channel of the media renderer 200 to the first input port 220 a as required. Accordingly, a personalized advert stream may be sent from the client terminal 120 to the media renderer 200 via the first input port 220 a for the duration of the advertising break in the media content stream. Optionally the system may be further operable to switch access back to the second port 220 b at the end of the advertising break, alternatively, the media content stream may be provided to the media renderer 200 via the client terminal 120 .
[0091] The user's profile of viewing preferences may use categorized context based on the nature of the media channels, social groups and social spaces. For example, sport related media channels may be categorized under a ‘SPORT CHANNELS’ category of social space. User group members may also be clustered into categories, groups, circles or the like. For example, a user may select members interested in leisure activities and group them in a ‘LEISURE USER GROUP’ user's category, or categorize them according to his social relationship therewith, such as “WORK”, “FRIENDS”, “FANTASY SPORTS LEAGUE”, etc.
[0092] Additionally, privacy data and access to current usage or recorded history data for any of the available media channels or their categorization may be stored in the user's preference profile. This may allow the limiting of exposure or access to this information to any other group member of any social space.
[0093] Optionally, limiting access may be effected by blocking access to current usage or recorded access history data for a specific media channel.
[0094] Optionally, limiting access may be effected by preventing the recording of usage data of a specific media channel or removing the channel altogether.
[0095] Optionally, the aforementioned limitations may be applied for at least one media channel or a set of media channels either selected manually or applied to a category encapsulating a group of media channels.
[0096] Optionally, the aforementioned limitations may be applied for at least one user group of social space specified by its group name, for example, or be applied to all members of all social spaces.
[0097] Referring now to FIG. 2 , showing another possible block diagram configuration for a network-based distributed system 100 ′ for content based control of a media renderer 200 with added functionality of hybrid advertising, centrally processed and managed. The network-based distributed system 100 ′ includes a client terminal 120 ′ and a central unit 130 ′ in communication with a network 150 , such as the World Wide Web, or a local area network or other such networked computing system.
[0098] The central unit 130 ′ may allow certain functionality of advertising processing of the system 100 ′ to be performed remotely and communicated to the client terminal 120 ′ via a modem 123 ′ providing a connection to the network 150 . For example, the central unit 130 ′ may be operable to receive media content data from a media monitor 124 ′, and to record a user profile related to media content accessed. The central unit 130 ′ may further have a processor 126 ′ receiving information, such as the current viewer preferences profile (with targeting characteristics) created locally on the client terminal 120 ′ or TV associated events from the client terminal 120 ′ to process and update viewer preference profile (with targeting characteristics) on the central unit 130 ′, controlling advertising content sent to this client terminal.
[0099] It is further noted that the central unit 130 ′ may communicate with other client terminals 121 . Accordingly, media data may be shared among multiple client terminals 120 ′, 121 . Where such data sharing is enabled, a social network may be established, for example, allowing users to form social contacts. Where appropriate, a user's social contacts may be provided with permission to access, e.g., in real time, usage data relating to the user's currently viewed channels, which may include, but it not limited to, the user's channel usage history, future usage schedule, preferences, and/or other relevant information. Such channel usage data may be selectively blocked from social contacts.
[0100] Although two different architectures are described herein, those skilled in the art will understand that other technologies may be used to implement the disclosed method of controlling advertising content.
[0101] As illustrated in FIG. 3 , an example of a method 300 is provided for limiting access to usage data. The usage data may include, but is not limited to, information related to current usage, future schedule, recorded history data, preferences, etc., of a specific media channel in a social TV or other media environment. The method 300 may be used in content based control of a media renderer management system, such as described hereinabove.
[0102] In step 302 , a user viewing profile is generated for collecting user behavior data and for storing user preferences. This behavior data may include, but is not limited to, one or more of viewing preferences, availability of media channels preferences, current usage and/or recorded history data preferences for media channel access, and user space categorization.
[0103] In step 304 , a set of media channels available for viewing on the client terminal is obtained. The set may be determined, for example, by a content provider in accordance with a package of channels purchased in advance.
[0104] In step 306 , a specific channel is selected from the set obtained in step 304 . In step 308 , the selected channel is assigned a limiting access setting for usage data. The usage data may include, but is not limited to, current usage, future schedule, and recorded history data. The limiting access setting may be selected from a group including, but not limited to, blocking access to history data, stopping recording of access data, removing the recorded data, etc.
[0105] In step 310 , a decision is made based on whether or not more channels remain to be assigned a limited access setting. If so (i.e., the decision for step 310 is “yes”), a further channel is selected, as described above with respect to step 306 , and the selected channel is assigned a limiting access setting as described above with respect to step 308 .
[0106] When the decision is reached in step 310 (e.g., after sufficient iterations of the steps 306 and 308 as described above are carried out) that no more channels remain to be assigned a limiting access setting, i.e., the decision for step 10 is “no”, the method 300 may optionally proceed to step 312 , wherein a menu is displayed providing additional functionality of limiting access.
[0107] Optionally, the content of the limiting access settings data may be stored locally, for example, in a memory of the STB, additionally or alternatively, the data may be transmitted to the central unit for storage.
[0108] The content based control of a media renderer management system may be configured to run locally on a processor of a client terminal, as indicated in FIG. 1 , or may run on a remote processor of a central unit of a network based system, as indicated in FIG. 2 . Applying access limitation is applicable to any of the system architectures brought as examples hereinabove.
[0109] It may be noted that for network based architecture such as indicated in FIG. 2 , some of the analytics may be performed on the controller of the terminal client. This may, for example, generate and maintain a local viewer preference profile.
[0110] Alternatively or additionally the system may send data pertaining to usage such as a viewer's watching behavior to the central unit and a viewer preference profile may be generated and maintained remotely.
[0111] As illustrated in FIG. 4 , another example of a method 400 for limiting access to usage data is provided. The usage data may include, but is not limited to, information related to current usage, future schedule, recorded history data, preferences, etc., of an assigned media channel category in a social TV or other media environment. The method 400 may be used in a content based control of a media renderer management system, such as described hereinabove.
[0112] In step 402 , a set of media channels available for viewing on the client terminal is obtained, for example based on an existing user viewing profile.
[0113] In step 404 , one or more media privacy categories are defined. Such categories may be given titles selected by the user, for example representing a desired social space, such as ‘SPORTS’, ‘HISTORY’, ‘FASHION’, ‘LEISURE’, etc.
[0114] In step 406 , a channel is selected from the available set of media channels obtained in step 402 . In step 408 , the selected media channel is assigned to one of the categories created in step 404 .
[0115] In step 410 , a decision is made based on whether or not more media channels are to be assigned to the media privacy category created in step 404 . If so (i.e., the decision for step 410 is “yes”), another media channel is selected as described above with reference to step 406 , and, as described above with reference to step 408 , the selected channel is assigned to one of the categories as described with reference to step 404 .
[0116] When the decision is reached in step 410 (e.g., after sufficient iterations of the steps 406 and 408 as described above are carried out) that no more channels remain to be assigned to one of the categories, i.e., the decision for step 10 is “no”, the method 400 proceeds to step 412 , wherein a limiting access attribute is assigned to all media channels in one or more of the media privacy categories.
[0117] In step 414 , a menu is optionally displayed providing additional available functionality related to limiting access.
[0118] FIG. 5A illustrates an example of a table 500 a for assignment of privacy settings to media channels in the context of limiting access to usage data. The usage data may include, but is not limited to, current usage, future schedule, recorded history data, etc., relating to a media channel in a social TV or other media environment.
[0119] The table 500 a includes a title bar 502 a, a media channel column 504 a, and a privacy attribute column 506 a. The table 500 a may, for example, be presented to a user as part of the graphical user interface allowing the user to assign privacy settings for selected channels.
[0120] The title bar 502 a comprises column headings 501 a, 501 a ′ and a ‘select-all’ box 503 a. The column headings indicate, for each media channel, its current privacy attribute setting. The ‘select-all’ box 503 a facilitates assigning ‘HIDE’ privacy attribute to all available media channels, by indicating a single box.
[0121] The media channel column 504 a may list all accessible media channels on the client terminal of the user, or a subset thereof.
[0122] The privacy attribute column 506 a may list, for each accessible media channel, the privacy attribute. Available privacy attributes may include, but are not limited to, ‘HIDE’, ‘NO-HIDE’, and attributes which social groups are granted/denied access.
[0123] The two columns of the table 500 a represent the set of available media channels 504 a and the settings 506 a of an attribute representing the privacy setting or accessibility to usage data relating to the associated media channel. A ‘HIDE’ setting may prevent usage data from being accessible, for example the usage history may not be recorded. A ‘NO-HIDE’ setting may determine that no limitation is placed upon the accessibility of usage data. A title bar 502 a may further include a ‘HIDE ALL’ box 503 a. Selecting the ‘select-all’ box 503 a may set all media channels of the set to the ‘HIDE’ setting thereby limiting access to usage data. Other privacy settings may be provided such as a CLOAK setting, for example, which may deliberately provide a false trail of usage data, such as recording a false history for the time during which a selected channel is accessed. Still further privacy settings will be readily apparent to those skilled in the art.
[0124] FIG. 5B illustrates an example of table 500 b for media channel classification of social-space categories for assignment of privacy settings in the context of limiting access to media channel usage data of all media channels associated with the social-space category in a social TV or other media environment.
[0125] The table 500 b comprises a title bar 502 b, several social-space category columns 506 b (it will be appreciated that although two social-space category columns 506 b are illustrated in FIG. 5B , the table 500 b may include as many as are required), and a set of channels 504 b not assigned to any social-space category. The table 500 b may be presented to a user as part of the graphical user interface allowing the user to assign privacy settings to a social-space category, e.g., to all associated media channels.
[0126] Each title bar 502 b comprises a column heading 501 b, e.g., indicating the relevant social-space category and associated media channels, and a ‘select-all’ box 503 b.
[0127] The social-space category columns 506 b may list all accessible media channels on the client terminal of the user associated with a social-space category. The unassigned category column may list all media channels not assigned yet to any social space category.
[0128] Optionally, it is noted that a media channel may be assigned to more than a single social space category.
[0129] The table 500 b may be presented to a user as part of the graphical user interface allowing the user to assign privacy attributes to a social space category. Such categories may be given titles selected by the user, for example, representing the desired social space category, such as ‘SPORTS’, ‘HISTORY’, ‘FASHION’, ‘LEISURE’, etc.
[0130] Selecting the ‘select-all’ box 503 b in the title of the setting attribute of a specific social-space category, may be used, for example, to set all media channels of the set to block viewing to the recorded usage data.
[0131] It is noted that additional social-space category columns 506 b may be created by the user for each new social space category.
[0132] FIG. 5C illustrates an additional interface for providing a similar functionality of assigning privacy an attribute to a classified set of media channels.
[0133] The table 500 c comprises a title bar 502 c, a separate social-space category column 504 c and a privacy attribute column 506 c.
[0134] The title bar 502 c comprises column headings 501 c and 501 c ′ for the social space category and for the privacy attribute, respectively.
[0135] The column of privacy attribute settings 506 c includes a ‘select-all’ box 503 c for each social space category entry in column 504 c. The column headings indicate a social space category and the associated privacy attribute settings.
[0136] The table 500 c may be presented to a user as part of the graphical user interface allowing the user to assign privacy attributes to a social space category. Such categories may be given titles selected by the user, for example, representing the desired social space category, such as ‘SPORTS’, ‘HISTORY’, ‘FASHION’, ‘LEISURE’, etc.
[0137] Selecting the ‘select-all’ box 503 c in the column of privacy attribute 506 c, for a specific social space category may be used to blocking access to recorded usage data of all media channels associated with the social space category selected, for example.
[0138] Optionally, it is noted that a media channel may be assigned to more than a single social space category.
[0139] FIG. 6 illustrates a further example of a table 600 which may be used as a graphical user interface. The table 600 presents selected actions of a method for providing personalized access permissions to media channel usage data, such as current usage, future schedule, recorded history data, preferences or the like, in a social TV or other media environment.
[0140] The table 600 includes a title bar 602 , a media channel column 604 , and a permission attribute column 606 . The table 600 may be presented to a user as part of the graphical user interface for assigning permission settings to selected users, lists of users or user groups to allow or to disallow access to recorded usage data, for example.
[0141] The title bar 602 consists of column headings 601 for available media channels and 601 ′ for specifying associated permission, and a ‘permit-all’ box 603 . The column headings indicate for each media channel its current permission settings. The ‘permit-all’ box 603 may allow assigning ‘ALL’ permission, to all media channels, allowing access to recorded usage data to all available media channels.
[0142] The media channel column 604 may list all accessible media channels on the client terminal of the user.
[0143] The permission attribute column 606 may list for each accessible media channel, the appropriate permission, including, but not limited to, ‘ALL’, ‘NONE’, a specific user, and a list of users or a specific user group.
[0144] The two columns of table 600 of represent a column of available media channels set 604 and a column of permission attributes settings 606 , for each media channel, representing allowed or disallowed accessibility to usage data of the associated media channel. A ‘NONE’ setting may disable accessibility to media channel usage data, for example. An ‘ALL’ setting may determine that no limitation is placed upon the accessibility of usage data, for example. A title bar 602 may further include a ‘permit-all’ box 603 . Selecting the ‘permit-all’ box 603 may set all media channels permission attribute to ‘ALL’ setting thereby allowing access to the usage data to all. Other permission settings may be provided such as allowing specific user/users, identified possibly by their system ID or name, to view specific history usage data of media channels or allow accessibility to users of a specific social group, identified by its assigned group ID or group name. Still further permission settings will be readily apparent to those skilled in the art.
[0145] Technical and scientific terms used herein should have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure pertains. Nevertheless, it is expected that during the life of a patent maturing from this application many relevant systems and methods will be developed. Accordingly, the scope of the terms such as computing unit, network, display, memory, server and the like are intended to include all such new technologies a priori.
[0146] As used herein the term “about” refers to at least ±10%.
[0147] The terms “comprises”, “comprising”, “includes”, “including”, “having” and their conjugates mean “including but not limited to” and indicate that the components listed are included, but not generally to the exclusion of other components. Such terms encompass the terms “consisting of” and “consisting essentially of”.
[0148] The phrase “consisting essentially of” means that the composition or method may include additional ingredients and/or steps, but only if the additional ingredients and/or steps do not materially alter the basic and novel characteristics of the claimed composition or method.
[0149] As used herein, the singular form “a”, “an” and “the” may include plural references unless the context clearly dictates otherwise. For example, the term “a compound” or “at least one compound” may include a plurality of compounds, including mixtures thereof.
[0150] The word “exemplary” is used herein to mean “serving as an example, instance or illustration”. Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or to exclude the incorporation of features from other embodiments.
[0151] The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments”. Any particular embodiment of the disclosure may include a plurality of “optional” features unless such features conflict.
[0152] Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween. It should be understood, therefore, that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6 as well as non-integral intermediate values. This applies regardless of the breadth of the range.
[0153] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the disclosure. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.
[0154] Although the disclosure has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
[0155] All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present disclosure. To the extent that section headings are used, they should not be construed as necessarily limiting.
[0156] The scope of the disclosed subject matter is defined by the appended claims and includes both combinations and sub combinations of the various features described hereinabove as well as variations and modifications thereof, which would occur to persons skilled in the art upon reading the foregoing description. | A method of sharing usage data of multimedia content is provided. The method comprises providing a set of media channels, providing access, to one or more pre-selected remote users, to usage data regarding consumption of the multimedia content, and selectively restricting access of at least a portion of the usage data to at least a portion of the remote users. | Identify the most important aspect in the document and summarize the concept accordingly. | [
"CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a Continuation of Applicant's co-pending U.S. patent application Ser.",
"No. 14/076,288 filed Nov. 11, 2013, which claims the benefit of priority from U.S. Provisional Patent Application No. 61/724,992, filed Nov. 11, 2012, the contents of which are incorporated by reference in their entirety.",
"FIELD OF THE INVENTION [0002] The disclosure herein relates to providing personalized settings for sharing viewed channels of a social media user.",
"In particular, the disclosure relates to the ability of providing members of a social group, the functionality to decide if usage of a specific channel is recorded and/or accessible to other online social network members.",
"BACKGROUND OF THE INVENTION [0003] Television sets have become commonplace in homes, businesses and institutions offering diversified digital content, with viewing considered as a passive and relaxing experience, limited to the place itself.",
"[0004] During the last few years, with advancement of technology, various developments have been made to provide television services on a social basis taking advantage of the relationship between individuals, connecting users watching public television content in different locations.",
"The vast amount of new electronic display devices adds to social television the concept of shared-viewing trends in creating a shift in television viewing from passive to active experience.",
"[0005] Social television introduced advanced technology which combines communication and social environment in the context of watching digital content, enabling the most common social television activity of watching digital content with others, allowing instant sharing of favorite digital media content with a social group.",
"Such systems may, for example, provide text chat, indicating the presence and context consciousness, integrate voice communication, viewing of recommendations, ratings or video-conferencing related to viewing digital content either directly on screen or by using supplementary devices.",
"[0006] Furthermore, the media viewing experience is turning richer with video content becoming available on increasingly diverse devices such as television, personal computers, tablets, mobile communication devices, telephones, hand held devices and the like.",
"In parallel, the social environment is changing, taking advantage of new emerging technologies and yielding a whole new world of experiences.",
"Television broadcasting networks continue to deliver digital content in diverse areas of interest, answering different tastes and flavors.",
"Combining the digital media, specifically the television as a platform, with the social environment increases the demand for sharing digital content and views.",
"[0007] Television is a wide reaching vehicle and a highly significant player in the digital media content domain.",
"Recent studies of consumer behavior and television measurements (eMarketer—Digital Intelligence, Nielsen) claim that 99% of American households watch television on a regular basis, with the average adult spending more time watching television than surfing the interest.",
"The report reveals that in 2010, the average adult spent about four and half hours per day watching television, compared to an average of just two and a half hours per day spent online.",
"[0008] Additionally, the percentage of American homes having at least one television set is reaching 99%, with two thirds of them owning at least three sets.",
"These numbers highlight the fact that television is still a most widespread and premier entertainment platform.",
"SUMMARY OF THE INVENTION [0009] It is an advantage of the current disclosure that an additional mode of operation is provided to allow controlling the exposure of media channel information, specifically limiting access to current usage or recorded history data, with minimal impact on user privacy.",
"[0010] While social television becomes more popular the exposure of media channel information may go beyond user expectations.",
"Users may want to control what is exposed to others and to what extent, specifically related to information of the channel currently viewed and more generally, control the exposure of the current usage or recorded data history of accessing all or specific media channels.",
"Such user control may provide functionality of blocking others completely or partially from accessing such recorded data.",
"[0011] Additionally, such control functionality may provide abilities of blocking access to currently viewed channels, removing the existing recorded data history, ceasing recording of such data or providing functionality of setting permissions for specific users or user groups of different social spaces.",
"[0012] In various embodiments of the disclosure, one or more tasks as described herein may be performed by a data processor, such as a computing platform or distributed computing system for executing a plurality of instructions.",
"Optionally, the data processor includes or accesses a volatile memory for storing instructions, data or the like.",
"Additionally or alternatively, the data processor may access a non-volatile storage, for example, a magnetic hard-disk, flash-drive, removable media or the like, for storing instructions and/or data.",
"[0013] Optionally, a network connection may additionally or alternatively be provided.",
"User interface devices may be provided such as visual displays, audio output devices, tactile outputs and the like.",
"Furthermore, as required, user input devices may be provided such as keyboards, cameras, microphones, accelerometers, motion detectors or pointing devices such as mice, roller balls, touch pads, touch sensitive screens or the like.",
"[0014] Optionally, a system may include a client terminal such as a set-top-box, mobile communication device or the like, which is operable to receive user defined preferences, monitor available media content and to control the input media renderer accordingly.",
"[0015] A set-top box (STB), referred to herein, may comprise an information appliance that connects to a television set and an external source of signal, decoding that signal into content that can be presented on a television unit or other display device.",
"[0016] Optionally, the media renderer may be selected from a group consisting of: televisions, media players, tablet computers, computers, digital picture frames, hand held devices and the like.",
"Where required, the client terminal may be selected from a group consisting of: set-top-boxes, mobile communication devices, remote control devices and telephones and the like.",
"[0017] The interaction with the user may be applied via a friendly user interface that may be driven by a management module.",
"Additionally, it may work in different possible architectures, for example using a network based approach to allow remote activities, or a locally managed approach.",
"[0018] In any of the above possible system architectures, the interests of a viewer in such a media socializing environment, may be reflected through a user preference profile, for example.",
"User preference profile may serve for storing user preferences, privacy data, social groups, social spaces and the like.",
"[0019] User groups and social spaces may be classified, for example, according to various preferences, tastes or interests of the user interacting and communicating in such a social environment.",
"Any member of a user space, may be authorized, by assigning permission to view shared recorded content.",
"This open access to shared data may be limited or narrowed by user profile definitions or may partially exclude specific user classified groups from viewing a part of the user social space data, by limiting access to current usage or recorded data history of media channels accessed.",
"[0020] Optionally, the user preference profile may be created and configured manually or automatically.",
"Manual configuration may designate categories of interests and the like, while automatic configuration may require machine learning algorithms or statistical analysis tools to deal with its complexity and high dimensionality.",
"[0021] According to one aspect of the presently disclosed subject matter, there is provided a method of sharing usage data of multimedia content, the method comprising: [0022] providing a set of media channels;",
"[0023] providing access, to one or more pre-selected remote users, to usage data regarding consumption of the multimedia content;",
"and [0024] selectively restricting access of at least a portion of the usage data to at least a portion of the remote users.",
"[0025] The method may further comprise: [0026] defining one or more remote user categories;",
"[0027] assigning at least some of the pre-selected remote users to the remote user categories;",
"and [0028] defining, for at least one or more of the remote user categories, access restrictions of at least a portion of the usage data for remote users assigned to the one or more remote user categories.",
"[0029] The method may further comprise: [0030] defining one or more media categories;",
"[0031] assigning at least some of the media channels to the media categories;",
"and [0032] defining, for at least one or more of the media categories, access restrictions of at least a portion of the usage data for media channels assigned to the one or more media categories.",
"[0033] The method may further comprise: [0034] defining one or more remote user categories and one or more media categories;",
"[0035] assigning at least some of the pre-selected remote users to the remote user categories, and at least some of the media channels to the media categories;",
"and [0036] defining, for at least one or more combinations of one of the remote user categories and one of the media categories, access restrictions of at least a portion of the usage data relating to media channels assigned to the media category, for remote users assigned to the remote user category.",
"[0037] The usage data may be selected from at least one of the group consisting of viewing history, recording history, user comments, and combinations thereof.",
"[0038] The selectively restricting access may be based on at least one of a time schedule and programming.",
"For example, a user may selectively restrict access to at least some usage data for viewing and/or recording during a predefined time, irrespective of programming, channel, etc.",
", thereby basing it on a time schedule.",
"Additionally or alternatively, a user may selectively restrict access to at least some usage data relating to a particular program, irrespective of scheduling or of which media channel it appears on, thereby basing it on programming.",
"[0039] According to another aspect of the presently disclosed subject matter, there is provided a computer implemented method for sharing usage data of multimedia content, the method comprising at least one processor executing instructions to perform the following operations: [0040] providing a set of media channels;",
"[0041] providing access, to one or more pre-selected remote users, to usage data regarding consumption of the multimedia content;",
"and [0042] selectively restricting access of at least a portion of the usage data to at least a portion of the remote users.",
"[0043] The computer implemented method may further comprise: [0044] defining one or more remote user categories;",
"[0045] assigning at least some of the pre-selected remote users to the remote user categories;",
"and [0046] defining, for at least one or more of the remote user categories, access restrictions of at least a portion of the usage data for remote users assigned to the one or more remote user categories.",
"[0047] The computer implemented method may further comprise: [0048] defining one or more media categories;",
"[0049] assigning at least some of the media channels to the media categories;",
"and [0050] defining, for at least one or more of the media categories, access restrictions of at least a portion of the usage data for media channels assigned to the one or more media categories.",
"[0051] The computer implemented method may further comprise: [0052] defining one or more remote user categories and one or more media categories;",
"[0053] assigning at least some of the pre-selected remote users to the remote user categories, and at least some of the media channels to the media categories;",
"and [0054] defining, for at least one or more combinations of one of the remote user categories and one of the media categories, access restrictions of at least a portion of the usage data relating to media channels assigned to the media category, for remote users assigned to the remote user category.",
"[0055] The usage data may be selected from at least one of the group consisting of: viewing history, recording history, user comments and combinations thereof.",
"[0056] The selectively restricting access may be based on at least one of a time schedule and programming.",
"[0057] According to a further aspect of the presently disclosed subject matter, there is provided a system for sharing usage data of multimedia content comprising a communication network in communication with a plurality of client terminals, the communication network comprising at least one central unit processor operable to: [0058] provide access, to one or more client terminals, to usage data regarding consumption of the multimedia content;",
"and [0059] selectively restrict access of at least a portion of the usage data to at least a portion of the client terminals.",
"[0060] The central processing unit may be further operable to: [0061] define one or more remote user categories;",
"[0062] assign at least some of the pre-selected remote users to the remote user categories;",
"and [0063] define, for at least one or more of the remote user categories, access restrictions of at least a portion of the usage data for remote users assigned to the one or more remote user categories.",
"[0064] The central processing unit may be further operable to: [0065] define one or more media categories;",
"[0066] assign at least some of the media channels to the media categories;",
"and [0067] define, for at least one or more of the media categories, access restrictions of at least a portion of the usage data for media channels assigned to the one or more media categories.",
"[0068] The central processing unit may be further operable to: [0069] define one or more remote user categories and one or more media categories;",
"[0070] assign at least some of the pre-selected remote users to the remote user categories, and at least some of the media channels to the media categories;",
"and [0071] define, for at least one or more combinations of one of the remote user categories and one of the media categories, access restrictions of at least a portion of the usage data relating to media channels assigned to the media category, for remote users assigned to the remote user category.",
"[0072] The usage data may be selected from at least one of the group consisting of: viewing history, recording history, user comments and combinations thereof.",
"[0073] The selectively restricting access may be based on one or more of a time schedule and programming.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0074] For a better understanding of the embodiments and to show how it may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings.",
"[0075] With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of selected embodiments only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects.",
"In this regard, no attempt is made to show structural details in more detail than is necessary for a fundamental understanding;",
"the description taken with the drawings making apparent to those skilled in the art how the various selected embodiments may be put into practice.",
"In the accompanying drawings: [0076] FIG. 1 is a block diagram representing one possible configuration of selected elements of a system for content based control of a media renderer with local processing;",
"[0077] FIG. 2 is a block diagram representing another possible configuration of a network-based distributed system for content based control of a media renderer with central processing and [0078] FIG. 3 is a flowchart representing possible selected actions of a method for limiting access to current usage or recorded history data of a media channel in a social TV or other media environment.",
"[0079] FIG. 4 is a flowchart representing possible selected actions of a method for limiting access to current usage or recorded history data of an assigned media channel category in a social TV or other media environment.",
"[0080] FIGS. 5A-5C are a set of tables representing a possible assignment of privacy settings to media channels in the context of limiting access to media channel data in a social TV or other media environment.",
"[0081] FIG. 6 is a table representing a possible assignment of privacy settings to media channels for providing personalized access permission to media channel data in a social TV or other media environment.",
"DETAILED DESCRIPTION OF THE INVENTION [0082] With reference to FIG. 1 , a block diagram is shown representing the major components of one possible configuration of selected elements of a system 100 for content based control of a media renderer 200 , with functionality of managing social interactivity in media viewing environment, locally processed and managed.",
"The system 100 includes a client terminal 120 in communication with a media content provider 140 and connected to the media renderer 200 via a communication channel 160 .",
"The client terminal 120 includes a processor 126 and may include additional components such as a controller 128 , a user interface 122 , and a media monitor 124 .",
"[0083] Optionally the user interface 122 of the client terminal 120 may be configured to allow a media consumer 110 to set preferences used by the system 100 to select control signals sent to the media renderer 200 .",
"Various user interfaces 122 configured to facilitate inputting data to the client terminal 120 by the user 110 are known in the art, such as keyboards, touch screens, remote controls, pointing devices, etc.",
"Optionally, the media renderer 200 may serve as at least part of the user interface 122 , for example by providing an output screen and/or an input device.",
"[0084] The processor 126 of the content-based control system 100 is operable to receive media content data from the media monitor 124 , and to record a user profile.",
"The user profile may contain data related, .",
"g, to media content accessed, and/or other relevant information.",
"[0085] The controller 128 may select control signals which it sends to the media renderer 200 .",
"[0086] It is noted that the media renderer may comprise a plurality of connector ports 220 a, 220 b, 220 c which may be connected to a number of media sources.",
"For example, a first port 220 a may be connected to the client terminal 120 ;",
"a second port 220 b may be connected to the media content provider 140 and a third port 220 c may be connected to a secondary media content provider 240 .",
"[0087] The management of privacy data, categorization of media channels or user groups, and current usage or recorded history data of accessing a media channel, may be controlled by the user viewing profile, for example, generated by a software package running on the client terminal processor 126 .",
"Such a profile may reflect the categories and preferences of viewing throughout the day or over longer time periods.",
"This viewing profile may be stored locally or may be sent to the media content provider for remote storage.",
"[0088] In some embodiments, a media stream may be accessed directly by the media renderer 220 , for example via the second input port 220 b. It will be appreciated that where the client terminal 120 is connected to the media renderer 200 via the first port 220 a, it will not have control over content accessed via the second input port 220 b. [0089] By way of illustration only, control signals may use the Consumer Electronics Control (CEC) feature available for example with HDMI connections or the like.",
"The CEC feature may allow a controller 128 to command and control the media renderer 200 by sending control signals via the client terminal 120 .",
"For example, CEC Routing Control allows a user to control the switching of signal sources between input channels.",
"[0090] Where required, the controller 128 may be operable to send control signals switching the input channel of the media renderer 200 to the first input port 220 a as required.",
"Accordingly, a personalized advert stream may be sent from the client terminal 120 to the media renderer 200 via the first input port 220 a for the duration of the advertising break in the media content stream.",
"Optionally the system may be further operable to switch access back to the second port 220 b at the end of the advertising break, alternatively, the media content stream may be provided to the media renderer 200 via the client terminal 120 .",
"[0091] The user's profile of viewing preferences may use categorized context based on the nature of the media channels, social groups and social spaces.",
"For example, sport related media channels may be categorized under a ‘SPORT CHANNELS’ category of social space.",
"User group members may also be clustered into categories, groups, circles or the like.",
"For example, a user may select members interested in leisure activities and group them in a ‘LEISURE USER GROUP’ user's category, or categorize them according to his social relationship therewith, such as “WORK”, “FRIENDS”, “FANTASY SPORTS LEAGUE”, etc.",
"[0092] Additionally, privacy data and access to current usage or recorded history data for any of the available media channels or their categorization may be stored in the user's preference profile.",
"This may allow the limiting of exposure or access to this information to any other group member of any social space.",
"[0093] Optionally, limiting access may be effected by blocking access to current usage or recorded access history data for a specific media channel.",
"[0094] Optionally, limiting access may be effected by preventing the recording of usage data of a specific media channel or removing the channel altogether.",
"[0095] Optionally, the aforementioned limitations may be applied for at least one media channel or a set of media channels either selected manually or applied to a category encapsulating a group of media channels.",
"[0096] Optionally, the aforementioned limitations may be applied for at least one user group of social space specified by its group name, for example, or be applied to all members of all social spaces.",
"[0097] Referring now to FIG. 2 , showing another possible block diagram configuration for a network-based distributed system 100 ′ for content based control of a media renderer 200 with added functionality of hybrid advertising, centrally processed and managed.",
"The network-based distributed system 100 ′ includes a client terminal 120 ′ and a central unit 130 ′ in communication with a network 150 , such as the World Wide Web, or a local area network or other such networked computing system.",
"[0098] The central unit 130 ′ may allow certain functionality of advertising processing of the system 100 ′ to be performed remotely and communicated to the client terminal 120 ′ via a modem 123 ′ providing a connection to the network 150 .",
"For example, the central unit 130 ′ may be operable to receive media content data from a media monitor 124 ′, and to record a user profile related to media content accessed.",
"The central unit 130 ′ may further have a processor 126 ′ receiving information, such as the current viewer preferences profile (with targeting characteristics) created locally on the client terminal 120 ′ or TV associated events from the client terminal 120 ′ to process and update viewer preference profile (with targeting characteristics) on the central unit 130 ′, controlling advertising content sent to this client terminal.",
"[0099] It is further noted that the central unit 130 ′ may communicate with other client terminals 121 .",
"Accordingly, media data may be shared among multiple client terminals 120 ′, 121 .",
"Where such data sharing is enabled, a social network may be established, for example, allowing users to form social contacts.",
"Where appropriate, a user's social contacts may be provided with permission to access, e.g., in real time, usage data relating to the user's currently viewed channels, which may include, but it not limited to, the user's channel usage history, future usage schedule, preferences, and/or other relevant information.",
"Such channel usage data may be selectively blocked from social contacts.",
"[0100] Although two different architectures are described herein, those skilled in the art will understand that other technologies may be used to implement the disclosed method of controlling advertising content.",
"[0101] As illustrated in FIG. 3 , an example of a method 300 is provided for limiting access to usage data.",
"The usage data may include, but is not limited to, information related to current usage, future schedule, recorded history data, preferences, etc.",
", of a specific media channel in a social TV or other media environment.",
"The method 300 may be used in content based control of a media renderer management system, such as described hereinabove.",
"[0102] In step 302 , a user viewing profile is generated for collecting user behavior data and for storing user preferences.",
"This behavior data may include, but is not limited to, one or more of viewing preferences, availability of media channels preferences, current usage and/or recorded history data preferences for media channel access, and user space categorization.",
"[0103] In step 304 , a set of media channels available for viewing on the client terminal is obtained.",
"The set may be determined, for example, by a content provider in accordance with a package of channels purchased in advance.",
"[0104] In step 306 , a specific channel is selected from the set obtained in step 304 .",
"In step 308 , the selected channel is assigned a limiting access setting for usage data.",
"The usage data may include, but is not limited to, current usage, future schedule, and recorded history data.",
"The limiting access setting may be selected from a group including, but not limited to, blocking access to history data, stopping recording of access data, removing the recorded data, etc.",
"[0105] In step 310 , a decision is made based on whether or not more channels remain to be assigned a limited access setting.",
"If so (i.e., the decision for step 310 is “yes”), a further channel is selected, as described above with respect to step 306 , and the selected channel is assigned a limiting access setting as described above with respect to step 308 .",
"[0106] When the decision is reached in step 310 (e.g., after sufficient iterations of the steps 306 and 308 as described above are carried out) that no more channels remain to be assigned a limiting access setting, i.e., the decision for step 10 is “no”, the method 300 may optionally proceed to step 312 , wherein a menu is displayed providing additional functionality of limiting access.",
"[0107] Optionally, the content of the limiting access settings data may be stored locally, for example, in a memory of the STB, additionally or alternatively, the data may be transmitted to the central unit for storage.",
"[0108] The content based control of a media renderer management system may be configured to run locally on a processor of a client terminal, as indicated in FIG. 1 , or may run on a remote processor of a central unit of a network based system, as indicated in FIG. 2 .",
"Applying access limitation is applicable to any of the system architectures brought as examples hereinabove.",
"[0109] It may be noted that for network based architecture such as indicated in FIG. 2 , some of the analytics may be performed on the controller of the terminal client.",
"This may, for example, generate and maintain a local viewer preference profile.",
"[0110] Alternatively or additionally the system may send data pertaining to usage such as a viewer's watching behavior to the central unit and a viewer preference profile may be generated and maintained remotely.",
"[0111] As illustrated in FIG. 4 , another example of a method 400 for limiting access to usage data is provided.",
"The usage data may include, but is not limited to, information related to current usage, future schedule, recorded history data, preferences, etc.",
", of an assigned media channel category in a social TV or other media environment.",
"The method 400 may be used in a content based control of a media renderer management system, such as described hereinabove.",
"[0112] In step 402 , a set of media channels available for viewing on the client terminal is obtained, for example based on an existing user viewing profile.",
"[0113] In step 404 , one or more media privacy categories are defined.",
"Such categories may be given titles selected by the user, for example representing a desired social space, such as ‘SPORTS’, ‘HISTORY’, ‘FASHION’, ‘LEISURE’, etc.",
"[0114] In step 406 , a channel is selected from the available set of media channels obtained in step 402 .",
"In step 408 , the selected media channel is assigned to one of the categories created in step 404 .",
"[0115] In step 410 , a decision is made based on whether or not more media channels are to be assigned to the media privacy category created in step 404 .",
"If so (i.e., the decision for step 410 is “yes”), another media channel is selected as described above with reference to step 406 , and, as described above with reference to step 408 , the selected channel is assigned to one of the categories as described with reference to step 404 .",
"[0116] When the decision is reached in step 410 (e.g., after sufficient iterations of the steps 406 and 408 as described above are carried out) that no more channels remain to be assigned to one of the categories, i.e., the decision for step 10 is “no”, the method 400 proceeds to step 412 , wherein a limiting access attribute is assigned to all media channels in one or more of the media privacy categories.",
"[0117] In step 414 , a menu is optionally displayed providing additional available functionality related to limiting access.",
"[0118] FIG. 5A illustrates an example of a table 500 a for assignment of privacy settings to media channels in the context of limiting access to usage data.",
"The usage data may include, but is not limited to, current usage, future schedule, recorded history data, etc.",
", relating to a media channel in a social TV or other media environment.",
"[0119] The table 500 a includes a title bar 502 a, a media channel column 504 a, and a privacy attribute column 506 a. The table 500 a may, for example, be presented to a user as part of the graphical user interface allowing the user to assign privacy settings for selected channels.",
"[0120] The title bar 502 a comprises column headings 501 a, 501 a ′ and a ‘select-all’ box 503 a. The column headings indicate, for each media channel, its current privacy attribute setting.",
"The ‘select-all’ box 503 a facilitates assigning ‘HIDE’ privacy attribute to all available media channels, by indicating a single box.",
"[0121] The media channel column 504 a may list all accessible media channels on the client terminal of the user, or a subset thereof.",
"[0122] The privacy attribute column 506 a may list, for each accessible media channel, the privacy attribute.",
"Available privacy attributes may include, but are not limited to, ‘HIDE’, ‘NO-HIDE’, and attributes which social groups are granted/denied access.",
"[0123] The two columns of the table 500 a represent the set of available media channels 504 a and the settings 506 a of an attribute representing the privacy setting or accessibility to usage data relating to the associated media channel.",
"A ‘HIDE’ setting may prevent usage data from being accessible, for example the usage history may not be recorded.",
"A ‘NO-HIDE’ setting may determine that no limitation is placed upon the accessibility of usage data.",
"A title bar 502 a may further include a ‘HIDE ALL’ box 503 a. Selecting the ‘select-all’ box 503 a may set all media channels of the set to the ‘HIDE’ setting thereby limiting access to usage data.",
"Other privacy settings may be provided such as a CLOAK setting, for example, which may deliberately provide a false trail of usage data, such as recording a false history for the time during which a selected channel is accessed.",
"Still further privacy settings will be readily apparent to those skilled in the art.",
"[0124] FIG. 5B illustrates an example of table 500 b for media channel classification of social-space categories for assignment of privacy settings in the context of limiting access to media channel usage data of all media channels associated with the social-space category in a social TV or other media environment.",
"[0125] The table 500 b comprises a title bar 502 b, several social-space category columns 506 b (it will be appreciated that although two social-space category columns 506 b are illustrated in FIG. 5B , the table 500 b may include as many as are required), and a set of channels 504 b not assigned to any social-space category.",
"The table 500 b may be presented to a user as part of the graphical user interface allowing the user to assign privacy settings to a social-space category, e.g., to all associated media channels.",
"[0126] Each title bar 502 b comprises a column heading 501 b, e.g., indicating the relevant social-space category and associated media channels, and a ‘select-all’ box 503 b. [0127] The social-space category columns 506 b may list all accessible media channels on the client terminal of the user associated with a social-space category.",
"The unassigned category column may list all media channels not assigned yet to any social space category.",
"[0128] Optionally, it is noted that a media channel may be assigned to more than a single social space category.",
"[0129] The table 500 b may be presented to a user as part of the graphical user interface allowing the user to assign privacy attributes to a social space category.",
"Such categories may be given titles selected by the user, for example, representing the desired social space category, such as ‘SPORTS’, ‘HISTORY’, ‘FASHION’, ‘LEISURE’, etc.",
"[0130] Selecting the ‘select-all’ box 503 b in the title of the setting attribute of a specific social-space category, may be used, for example, to set all media channels of the set to block viewing to the recorded usage data.",
"[0131] It is noted that additional social-space category columns 506 b may be created by the user for each new social space category.",
"[0132] FIG. 5C illustrates an additional interface for providing a similar functionality of assigning privacy an attribute to a classified set of media channels.",
"[0133] The table 500 c comprises a title bar 502 c, a separate social-space category column 504 c and a privacy attribute column 506 c. [0134] The title bar 502 c comprises column headings 501 c and 501 c ′ for the social space category and for the privacy attribute, respectively.",
"[0135] The column of privacy attribute settings 506 c includes a ‘select-all’ box 503 c for each social space category entry in column 504 c. The column headings indicate a social space category and the associated privacy attribute settings.",
"[0136] The table 500 c may be presented to a user as part of the graphical user interface allowing the user to assign privacy attributes to a social space category.",
"Such categories may be given titles selected by the user, for example, representing the desired social space category, such as ‘SPORTS’, ‘HISTORY’, ‘FASHION’, ‘LEISURE’, etc.",
"[0137] Selecting the ‘select-all’ box 503 c in the column of privacy attribute 506 c, for a specific social space category may be used to blocking access to recorded usage data of all media channels associated with the social space category selected, for example.",
"[0138] Optionally, it is noted that a media channel may be assigned to more than a single social space category.",
"[0139] FIG. 6 illustrates a further example of a table 600 which may be used as a graphical user interface.",
"The table 600 presents selected actions of a method for providing personalized access permissions to media channel usage data, such as current usage, future schedule, recorded history data, preferences or the like, in a social TV or other media environment.",
"[0140] The table 600 includes a title bar 602 , a media channel column 604 , and a permission attribute column 606 .",
"The table 600 may be presented to a user as part of the graphical user interface for assigning permission settings to selected users, lists of users or user groups to allow or to disallow access to recorded usage data, for example.",
"[0141] The title bar 602 consists of column headings 601 for available media channels and 601 ′ for specifying associated permission, and a ‘permit-all’ box 603 .",
"The column headings indicate for each media channel its current permission settings.",
"The ‘permit-all’ box 603 may allow assigning ‘ALL’ permission, to all media channels, allowing access to recorded usage data to all available media channels.",
"[0142] The media channel column 604 may list all accessible media channels on the client terminal of the user.",
"[0143] The permission attribute column 606 may list for each accessible media channel, the appropriate permission, including, but not limited to, ‘ALL’, ‘NONE’, a specific user, and a list of users or a specific user group.",
"[0144] The two columns of table 600 of represent a column of available media channels set 604 and a column of permission attributes settings 606 , for each media channel, representing allowed or disallowed accessibility to usage data of the associated media channel.",
"A ‘NONE’ setting may disable accessibility to media channel usage data, for example.",
"An ‘ALL’ setting may determine that no limitation is placed upon the accessibility of usage data, for example.",
"A title bar 602 may further include a ‘permit-all’ box 603 .",
"Selecting the ‘permit-all’ box 603 may set all media channels permission attribute to ‘ALL’ setting thereby allowing access to the usage data to all.",
"Other permission settings may be provided such as allowing specific user/users, identified possibly by their system ID or name, to view specific history usage data of media channels or allow accessibility to users of a specific social group, identified by its assigned group ID or group name.",
"Still further permission settings will be readily apparent to those skilled in the art.",
"[0145] Technical and scientific terms used herein should have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure pertains.",
"Nevertheless, it is expected that during the life of a patent maturing from this application many relevant systems and methods will be developed.",
"Accordingly, the scope of the terms such as computing unit, network, display, memory, server and the like are intended to include all such new technologies a priori.",
"[0146] As used herein the term “about”",
"refers to at least ±10%.",
"[0147] The terms “comprises”, “comprising”, “includes”, “including”, “having”",
"and their conjugates mean “including but not limited to”",
"and indicate that the components listed are included, but not generally to the exclusion of other components.",
"Such terms encompass the terms “consisting of”",
"and “consisting essentially of.”",
"[0148] The phrase “consisting essentially of”",
"means that the composition or method may include additional ingredients and/or steps, but only if the additional ingredients and/or steps do not materially alter the basic and novel characteristics of the claimed composition or method.",
"[0149] As used herein, the singular form “a”, “an”",
"and “the”",
"may include plural references unless the context clearly dictates otherwise.",
"For example, the term “a compound”",
"or “at least one compound”",
"may include a plurality of compounds, including mixtures thereof.",
"[0150] The word “exemplary”",
"is used herein to mean “serving as an example, instance or illustration.”",
"Any embodiment described as “exemplary”",
"is not necessarily to be construed as preferred or advantageous over other embodiments or to exclude the incorporation of features from other embodiments.",
"[0151] The word “optionally”",
"is used herein to mean “is provided in some embodiments and not provided in other embodiments.”",
"Any particular embodiment of the disclosure may include a plurality of “optional”",
"features unless such features conflict.",
"[0152] Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range.",
"The phrases “ranging/ranges between”",
"a first indicate number and a second indicate number and “ranging/ranges from”",
"a first indicate number “to”",
"a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.",
"It should be understood, therefore, that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure.",
"Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range.",
"For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc.",
", as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6 as well as non-integral intermediate values.",
"This applies regardless of the breadth of the range.",
"[0153] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment.",
"Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the disclosure.",
"Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.",
"[0154] Although the disclosure has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art.",
"Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.",
"[0155] All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference.",
"In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present disclosure.",
"To the extent that section headings are used, they should not be construed as necessarily limiting.",
"[0156] The scope of the disclosed subject matter is defined by the appended claims and includes both combinations and sub combinations of the various features described hereinabove as well as variations and modifications thereof, which would occur to persons skilled in the art upon reading the foregoing description."
] |
[0001] Cross-reference is made to U.S. Utility patent application Ser. No. 12/437,576 entitled “Li-ion Battery with Selective Moderating Material” by John F. Christensen et al., which was filed on May 8, 2009; U.S. Utility patent application Ser. No. 12/437,592 entitled “Li-ion Battery with Blended Electrode” by John F. Christensen et al., which was filed on May 8, 2009; U.S. Utility patent application Ser. No. 12/437,606 entitled “Li-ion Battery with Variable Volume Reservoir” by John F. Christensen et al., which was filed on May 8, 2009; U.S. Utility patent application Ser. No. 12/437,622 entitled “Li-ion Battery with Over-charge/Over-discharge Failsafe” by John F. Christensen et al., which was filed on May 8, 2009; U.S. Utility patent application Ser. No. 12/437,643 entitled “System and Method for Pressure Determination in a Li-ion Battery” by John F. Christensen et al., which was filed on May 8, 2009; U.S. Utility patent application Ser. No. 12/437,745 entitled “Li-ion Battery with Load Leveler” by John F. Christensen et al., which was filed on May 8, 2009; U.S. Utility Patent Application Serial No. [Attorney Docket No. 1576-0304] entitled “Li-ion Battery with Anode Expansion Area” by Boris Kozinsky et al., which was filed on May 8, 2009; U.S. Utility Patent Application Serial No. [Attorney Docket No. 1576-0305] entitled “Li-ion Battery with Porous Silicon Anode” by Boris Kozinsky et al., which was filed on May 8, 2009; U.S. Utility Patent Application Serial No. [Attorney Docket No. 1576-0306] entitled “Li-ion Battery with Rigid Anode Framework” by Boris Kozinsky et al., which was filed on May 8, 2009; U.S. Utility Patent Application Serial No. [Attorney Docket No. 1576-0308] entitled “System and Method for Charging and Discharging a Li-ion Battery” by Nalin Chaturvedi et al., which was filed on May 8, 2009; and U.S. Utility Patent Application Serial No. [Attorney Docket No. 1576-0310] entitled “System and Method for Charging and Discharging a Li-ion Battery Pack” by Nalin Chaturvedi et al., which was filed on May 8, 2009, the entirety of each of which is incorporated herein by reference. The principles of the present invention may be combined with features disclosed in those patent applications.
FIELD OF THE INVENTION
[0002] This invention relates to batteries and more particularly to lithium-ion batteries.
BACKGROUND
[0003] Batteries are a useful source of stored energy that can be incorporated into a number of systems. Rechargeable lithium-ion batteries are attractive energy storage systems for portable electronics and electric and hybrid-electric vehicles because of their high specific energy compared to other electrochemical energy storage devices. In particular, batteries with a form of lithium metal incorporated into the negative electrode afford exceptionally high specific energy (in Wh/kg) and energy density (in Wh/L) compared to batteries with conventional carbonaceous negative electrodes.
[0004] When high-specific-capacity negative electrodes such as lithium are used in a battery, the maximum benefit of the capacity increase over conventional systems is realized when a high-capacity positive electrode active material is also used. Conventional lithium-intercalating oxides (e.g., LiCoO 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , Li 1.1 Ni 0.3 Co 0.3 Mn 0.3 O 2 ) are typically limited to a theoretical capacity of ˜280 mAh/g (based on the mass of the lithiated oxide) and a practical capacity of 180 to 250 mAh/g. In comparison, the specific capacity of lithium metal is about 3863 mAh/g. The highest theoretical capacity achievable for a lithium-ion positive electrode is 1168 mAh/g (based on the mass of the lithiated material), which is shared by Li 2 S and Li 2 O 2 . Other high-capacity materials including BiF 3 (303 mAh/g, lithiated) and FeF 3 (712 mAh/g, lithiated) are identified in Amatucci, G. G. and N. Pereira, Fluoride based electrode materials for advanced energy storage devices. Journal of Fluorine Chemistry, 2007. 128(4): p. 243-262. All of the foregoing materials, however, react with lithium at a lower voltage compared to conventional oxide positive electrodes, hence limiting the theoretical specific energy. The theoretical specific energies of the foregoing materials, however, are very high (>800 Wh/kg, compared to a maximum of ˜500 Wh/kg for a cell with lithium negative and conventional oxide positive electrodes).
[0005] Lithium/sulfur (Li/S) batteries are particularly attractive because of the balance between high specific energy (i.e., >350 Wh/kg has been demonstrated), rate capability, and cycle life (>50 cycles). Only lithium/air batteries have a higher theoretical specific energy. Lithium/air batteries, however, have very limited rechargeability and are still considered primary batteries.
[0006] While generally safe, the amount of energy stored within a battery as well as the materials used to manufacture the battery can present safety issues under different scenarios. Safety is particularly an issue when a battery is subjected to increased temperatures either as a result of internal processes or as a result of the environment in which the battery is located.
[0007] By way of example, when batteries are charged or discharged, they typically generate heat due to a finite internal resistance that includes ohmic, mass-transfer, and kinetic contributions. Exothermic side reactions can also generate heat within the battery. This heat generation can pose a safety risk if it is large and rapid. For instance, commercial Li-ion cells generally go into thermal runaway if the internal cell temperature climbs above the decomposition temperature of the cathode (˜180 to 220° C., depending upon the chemistry and the state of charge). Often the events that lead to a temperature rise above this critical temperature are triggered at much lower temperatures. For example, exothermic anode film decomposition can occur at ˜120° C., providing enough energy to raise the battery temperature above 180° C. Excessive temperature in a battery may lead to venting of gases, smoke, flames, and, in rare cases, explosion.
[0008] Undesired amounts of heat may also be generated in a battery due to undesired physical changes in the battery. By way of example, formation of an electronically conducting phase between the two electrodes (i.e., internal shorting) of the battery can lead to excessive internal discharge. Internal shorting may be caused by dendrite formation, separator melting, separator cracking, separator tearing, pinholes, or growth of some conductive material through the separator. Thus, in addition to safety concerns, dendrite formation can significantly shorten the lifespan o an electrochemical cell.
[0009] What is needed therefore is a battery that is less susceptible to dendrite formation.
SUMMARY
[0010] In accordance with one embodiment, an electrochemical cell includes a negative electrode including a form of lithium, a positive electrode spaced apart from the negative electrode, an electrolyte, a separator positioned between the negative electrode and the positive electrode, and a current collector in the negative electrode, the current collector including a substrate material and a coating material on the surface of the substrate material, wherein the coating material does not include a form of lithium.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 depicts a schematic of an electrochemical cell with one electrode including a form of lithium and having a coating applied to the current collector to assist in forming a smooth lithium layer.
DESCRIPTION
[0012] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the invention is thereby intended. It is further understood that the present invention includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the invention as would normally occur to one skilled in the art to which this invention pertains.
[0013] FIG. 1 depicts a lithium-ion cell 100 , which includes a negative electrode 102 , a positive electrode 104 , and a separator region 106 between the negative electrode 102 and the positive electrode 104 . The negative electrode 102 includes electrolyte 112 and a current collector 114 . A coating 116 is provided on the current collector 114 .
[0014] The negative electrode 102 may be provided in various alternative forms. The negative electrode 102 may incorporate a dense form of Li metal or a in a porous composite electrode. Incorporation of Li metal is desired since the Li metal affords a higher specific energy than graphite.
[0015] The separator region 106 includes an electrolyte with a lithium cation and serves as a physical and electrical barrier between the negative electrode 102 and the positive electrode 104 so that the electrodes are not electronically connected within the cell 100 while allowing transfer of lithium ions between the negative electrode 102 and the positive electrode 104 .
[0016] The positive electrode 104 includes active material 120 into which lithium can be inserted, inert materials 124 , the electrolyte 112 and a current collector 126 . The active material 120 may include a form of sulfur and may be entirely sulfur. The active material 120 may incorporate a form of lithium such as a Li—SI alloy or a Li—Sn alloy.
[0017] The lithium-ion cell 100 operates in a manner similar to the lithium-ion battery cell disclosed in U.S. patent application Ser. No. 11/477,404, filed on Jun. 28, 2006, the contents of which are herein incorporated in their entirety by reference. In general, electrons are generated at the negative electrode 102 during discharging and an equal amount of electrons are consumed at the positive electrode 104 as lithium and electrons move in the direction of the arrow 130 of FIG. 1 .
[0018] In the ideal discharging of the cell 100 , the electrons are generated at the negative electrode 102 because there is extraction via oxidation of lithium ions as lithium is plated on the coating 116 of the negative electrode 102 , and the electrons are consumed at the positive electrode 104 because metal cations or sulfur ions change oxidation state in the positive electrode 104 . During charging, the reactions are reversed, with lithium and electrons moving in the direction of the arrow 132 .
[0019] The physical characteristics of the lithium layer that is formed on the current collector 114 is influenced by the coating 116 . Specifically, use of pure forms of Li can result in shortened lifespan of a cell because Li is highly reactive. Accordingly, upon repeated cycling of a Li-anode cell, the anode undergoes significant morphology changes. For example, the initially dense metal, after a number of cycles, develops surface roughness and a sponge-like morphology. This morphology is dangerous due to increased surface area which increases the chance and severity of runaway reactions, and due to growth of metallic dendrites that can puncture the separator and cause an internal short of the cell.
[0020] The inventors believe that surface roughness develops partly because Li deposition onto the current collector during cell charging happens non-uniformly. This non-uniformity is caused in part by roughness and defects on the atomic level of the anodic current collector 114 (typically Cu metal). Li metal plating nucleates at these defect sites and the subsequent growth pattern of Li is determined by these initial sites.
[0021] The coating 116 , however, encourages the growth of a smooth layer of lithium on the collector 114 regardless of surface imperfections in the substrate material. In one embodiment, this is accomplished by providing a coating 116 that exhibits a smoother surface for lithium adherence as compared to the substrate material. Accordingly, the lithium coats more uniformly onto the current collector 114 .
[0022] Thus, by making the surface of the coating 116 very smooth, the anode morphology is improved thereby extending the cycle life and safety of the cell. The coating 116 may be provided in the form of pure metals and alloys, conducting oxides such as indium oxide or zinc oxide, or sulfides, etc. The coating 116 can be applied by a sputtering process or chemical deposition onto the current collector 114 during the assembly of the cell 100 .
[0023] Preferably, the coating 116 is very thin to reduce cost and effects on electronic conductivity. The coating 116 need only be sufficiently thick to provide a very smooth surface on which Li metal can be electrochemically deposited with minimal initial development of roughness.
[0024] In another embodiment, the coating 116 is in the form of a thin electronically conductive coating that it has high chemical affinity for Li metal. Accordingly, the coating 116 functions as a wetting agent so that during cell charge Li does not form isolated islands or beads but rather spreads uniformly, “wetting” the entire surface of the current collector. By selecting a material with a sufficiently high affinity for Li, such as tin, magnesium, aluminum, or graphite, Li will form a uniform layer even if the coating 116 exhibits a surface roughness similar to the surface roughness of a Cu anode.
[0025] While the invention has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the invention are desired to be protected. | An electrochemical cell in one embodiment includes a negative electrode including a form of lithium, a positive electrode spaced apart from the negative electrode, an electrolyte, a separator positioned between the negative electrode and the positive electrode, and a current collector in the negative electrode, the current collector including a substrate material and a coating material on the surface of the substrate material, wherein the coating material does not include a form of lithium. | Summarize the document in concise, focusing on the main idea's functionality and advantages. | [
"[0001] Cross-reference is made to U.S. Utility patent application Ser.",
"No. 12/437,576 entitled “Li-ion Battery with Selective Moderating Material”",
"by John F. Christensen et al.",
", which was filed on May 8, 2009;",
"U.S. Utility patent application Ser.",
"No. 12/437,592 entitled “Li-ion Battery with Blended Electrode”",
"by John F. Christensen et al.",
", which was filed on May 8, 2009;",
"U.S. Utility patent application Ser.",
"No. 12/437,606 entitled “Li-ion Battery with Variable Volume Reservoir”",
"by John F. Christensen et al.",
", which was filed on May 8, 2009;",
"U.S. Utility patent application Ser.",
"No. 12/437,622 entitled “Li-ion Battery with Over-charge/Over-discharge Failsafe”",
"by John F. Christensen et al.",
", which was filed on May 8, 2009;",
"U.S. Utility patent application Ser.",
"No. 12/437,643 entitled “System and Method for Pressure Determination in a Li-ion Battery”",
"by John F. Christensen et al.",
", which was filed on May 8, 2009;",
"U.S. Utility patent application Ser.",
"No. 12/437,745 entitled “Li-ion Battery with Load Leveler”",
"by John F. Christensen et al.",
", which was filed on May 8, 2009;",
"U.S. Utility Patent Application Serial No. [Attorney Docket No. 1576-0304] entitled “Li-ion Battery with Anode Expansion Area”",
"by Boris Kozinsky et al.",
", which was filed on May 8, 2009;",
"U.S. Utility Patent Application Serial No. [Attorney Docket No. 1576-0305] entitled “Li-ion Battery with Porous Silicon Anode”",
"by Boris Kozinsky et al.",
", which was filed on May 8, 2009;",
"U.S. Utility Patent Application Serial No. [Attorney Docket No. 1576-0306] entitled “Li-ion Battery with Rigid Anode Framework”",
"by Boris Kozinsky et al.",
", which was filed on May 8, 2009;",
"U.S. Utility Patent Application Serial No. [Attorney Docket No. 1576-0308] entitled “System and Method for Charging and Discharging a Li-ion Battery”",
"by Nalin Chaturvedi et al.",
", which was filed on May 8, 2009;",
"and U.S. Utility Patent Application Serial No. [Attorney Docket No. 1576-0310] entitled “System and Method for Charging and Discharging a Li-ion Battery Pack”",
"by Nalin Chaturvedi et al.",
", which was filed on May 8, 2009, the entirety of each of which is incorporated herein by reference.",
"The principles of the present invention may be combined with features disclosed in those patent applications.",
"FIELD OF THE INVENTION [0002] This invention relates to batteries and more particularly to lithium-ion batteries.",
"BACKGROUND [0003] Batteries are a useful source of stored energy that can be incorporated into a number of systems.",
"Rechargeable lithium-ion batteries are attractive energy storage systems for portable electronics and electric and hybrid-electric vehicles because of their high specific energy compared to other electrochemical energy storage devices.",
"In particular, batteries with a form of lithium metal incorporated into the negative electrode afford exceptionally high specific energy (in Wh/kg) and energy density (in Wh/L) compared to batteries with conventional carbonaceous negative electrodes.",
"[0004] When high-specific-capacity negative electrodes such as lithium are used in a battery, the maximum benefit of the capacity increase over conventional systems is realized when a high-capacity positive electrode active material is also used.",
"Conventional lithium-intercalating oxides (e.g., LiCoO 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , Li 1.1 Ni 0.3 Co 0.3 Mn 0.3 O 2 ) are typically limited to a theoretical capacity of ˜280 mAh/g (based on the mass of the lithiated oxide) and a practical capacity of 180 to 250 mAh/g.",
"In comparison, the specific capacity of lithium metal is about 3863 mAh/g.",
"The highest theoretical capacity achievable for a lithium-ion positive electrode is 1168 mAh/g (based on the mass of the lithiated material), which is shared by Li 2 S and Li 2 O 2 .",
"Other high-capacity materials including BiF 3 (303 mAh/g, lithiated) and FeF 3 (712 mAh/g, lithiated) are identified in Amatucci, G. G. and N. Pereira, Fluoride based electrode materials for advanced energy storage devices.",
"Journal of Fluorine Chemistry, 2007.",
"128(4): p. 243-262.",
"All of the foregoing materials, however, react with lithium at a lower voltage compared to conventional oxide positive electrodes, hence limiting the theoretical specific energy.",
"The theoretical specific energies of the foregoing materials, however, are very high (>800 Wh/kg, compared to a maximum of ˜500 Wh/kg for a cell with lithium negative and conventional oxide positive electrodes).",
"[0005] Lithium/sulfur (Li/S) batteries are particularly attractive because of the balance between high specific energy (i.e., >350 Wh/kg has been demonstrated), rate capability, and cycle life (>50 cycles).",
"Only lithium/air batteries have a higher theoretical specific energy.",
"Lithium/air batteries, however, have very limited rechargeability and are still considered primary batteries.",
"[0006] While generally safe, the amount of energy stored within a battery as well as the materials used to manufacture the battery can present safety issues under different scenarios.",
"Safety is particularly an issue when a battery is subjected to increased temperatures either as a result of internal processes or as a result of the environment in which the battery is located.",
"[0007] By way of example, when batteries are charged or discharged, they typically generate heat due to a finite internal resistance that includes ohmic, mass-transfer, and kinetic contributions.",
"Exothermic side reactions can also generate heat within the battery.",
"This heat generation can pose a safety risk if it is large and rapid.",
"For instance, commercial Li-ion cells generally go into thermal runaway if the internal cell temperature climbs above the decomposition temperature of the cathode (˜180 to 220° C., depending upon the chemistry and the state of charge).",
"Often the events that lead to a temperature rise above this critical temperature are triggered at much lower temperatures.",
"For example, exothermic anode film decomposition can occur at ˜120° C., providing enough energy to raise the battery temperature above 180° C. Excessive temperature in a battery may lead to venting of gases, smoke, flames, and, in rare cases, explosion.",
"[0008] Undesired amounts of heat may also be generated in a battery due to undesired physical changes in the battery.",
"By way of example, formation of an electronically conducting phase between the two electrodes (i.e., internal shorting) of the battery can lead to excessive internal discharge.",
"Internal shorting may be caused by dendrite formation, separator melting, separator cracking, separator tearing, pinholes, or growth of some conductive material through the separator.",
"Thus, in addition to safety concerns, dendrite formation can significantly shorten the lifespan o an electrochemical cell.",
"[0009] What is needed therefore is a battery that is less susceptible to dendrite formation.",
"SUMMARY [0010] In accordance with one embodiment, an electrochemical cell includes a negative electrode including a form of lithium, a positive electrode spaced apart from the negative electrode, an electrolyte, a separator positioned between the negative electrode and the positive electrode, and a current collector in the negative electrode, the current collector including a substrate material and a coating material on the surface of the substrate material, wherein the coating material does not include a form of lithium.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIG. 1 depicts a schematic of an electrochemical cell with one electrode including a form of lithium and having a coating applied to the current collector to assist in forming a smooth lithium layer.",
"DESCRIPTION [0012] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification.",
"It is understood that no limitation to the scope of the invention is thereby intended.",
"It is further understood that the present invention includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the invention as would normally occur to one skilled in the art to which this invention pertains.",
"[0013] FIG. 1 depicts a lithium-ion cell 100 , which includes a negative electrode 102 , a positive electrode 104 , and a separator region 106 between the negative electrode 102 and the positive electrode 104 .",
"The negative electrode 102 includes electrolyte 112 and a current collector 114 .",
"A coating 116 is provided on the current collector 114 .",
"[0014] The negative electrode 102 may be provided in various alternative forms.",
"The negative electrode 102 may incorporate a dense form of Li metal or a in a porous composite electrode.",
"Incorporation of Li metal is desired since the Li metal affords a higher specific energy than graphite.",
"[0015] The separator region 106 includes an electrolyte with a lithium cation and serves as a physical and electrical barrier between the negative electrode 102 and the positive electrode 104 so that the electrodes are not electronically connected within the cell 100 while allowing transfer of lithium ions between the negative electrode 102 and the positive electrode 104 .",
"[0016] The positive electrode 104 includes active material 120 into which lithium can be inserted, inert materials 124 , the electrolyte 112 and a current collector 126 .",
"The active material 120 may include a form of sulfur and may be entirely sulfur.",
"The active material 120 may incorporate a form of lithium such as a Li—SI alloy or a Li—Sn alloy.",
"[0017] The lithium-ion cell 100 operates in a manner similar to the lithium-ion battery cell disclosed in U.S. patent application Ser.",
"No. 11/477,404, filed on Jun. 28, 2006, the contents of which are herein incorporated in their entirety by reference.",
"In general, electrons are generated at the negative electrode 102 during discharging and an equal amount of electrons are consumed at the positive electrode 104 as lithium and electrons move in the direction of the arrow 130 of FIG. 1 .",
"[0018] In the ideal discharging of the cell 100 , the electrons are generated at the negative electrode 102 because there is extraction via oxidation of lithium ions as lithium is plated on the coating 116 of the negative electrode 102 , and the electrons are consumed at the positive electrode 104 because metal cations or sulfur ions change oxidation state in the positive electrode 104 .",
"During charging, the reactions are reversed, with lithium and electrons moving in the direction of the arrow 132 .",
"[0019] The physical characteristics of the lithium layer that is formed on the current collector 114 is influenced by the coating 116 .",
"Specifically, use of pure forms of Li can result in shortened lifespan of a cell because Li is highly reactive.",
"Accordingly, upon repeated cycling of a Li-anode cell, the anode undergoes significant morphology changes.",
"For example, the initially dense metal, after a number of cycles, develops surface roughness and a sponge-like morphology.",
"This morphology is dangerous due to increased surface area which increases the chance and severity of runaway reactions, and due to growth of metallic dendrites that can puncture the separator and cause an internal short of the cell.",
"[0020] The inventors believe that surface roughness develops partly because Li deposition onto the current collector during cell charging happens non-uniformly.",
"This non-uniformity is caused in part by roughness and defects on the atomic level of the anodic current collector 114 (typically Cu metal).",
"Li metal plating nucleates at these defect sites and the subsequent growth pattern of Li is determined by these initial sites.",
"[0021] The coating 116 , however, encourages the growth of a smooth layer of lithium on the collector 114 regardless of surface imperfections in the substrate material.",
"In one embodiment, this is accomplished by providing a coating 116 that exhibits a smoother surface for lithium adherence as compared to the substrate material.",
"Accordingly, the lithium coats more uniformly onto the current collector 114 .",
"[0022] Thus, by making the surface of the coating 116 very smooth, the anode morphology is improved thereby extending the cycle life and safety of the cell.",
"The coating 116 may be provided in the form of pure metals and alloys, conducting oxides such as indium oxide or zinc oxide, or sulfides, etc.",
"The coating 116 can be applied by a sputtering process or chemical deposition onto the current collector 114 during the assembly of the cell 100 .",
"[0023] Preferably, the coating 116 is very thin to reduce cost and effects on electronic conductivity.",
"The coating 116 need only be sufficiently thick to provide a very smooth surface on which Li metal can be electrochemically deposited with minimal initial development of roughness.",
"[0024] In another embodiment, the coating 116 is in the form of a thin electronically conductive coating that it has high chemical affinity for Li metal.",
"Accordingly, the coating 116 functions as a wetting agent so that during cell charge Li does not form isolated islands or beads but rather spreads uniformly, “wetting”",
"the entire surface of the current collector.",
"By selecting a material with a sufficiently high affinity for Li, such as tin, magnesium, aluminum, or graphite, Li will form a uniform layer even if the coating 116 exhibits a surface roughness similar to the surface roughness of a Cu anode.",
"[0025] While the invention has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character.",
"It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the invention are desired to be protected."
] |
This application is a continuation of application Ser. No. 08/389,296, filed Feb. 16, 1995, now abandoned.
FIELD OF THE INVENTION
This invention relates to methods for detecting the existence of harmful levels of bacterial growth in packaged foods.
BACKGROUND OF THE INVENTION
The presence of undesirable bacteria, for example, Botulism sp., among others, in food products intended for human consumption has recently caused increased concern among food product manufacturers. This is due to the potential that contaminated food has for serious illness or even death as a consequence of its ingestion by the consumer. While it would be desirable to monitor contamination in every sample of food, in most cases, it is simply not possible to detect the presence of contaminating bacteria by visual or other inspection. Consequently, chemical means must be used to facilitate such detection.
Although food is generally inspected prior to its being canned, it is presently not practical to inspect each can of food for contamination.
OBJECTS OF THE INVENTION
It is an object of the invention to provide a method for detecting the presence of contaminating bacteria in a food sample, especially a food sample which has been stored in cans or other packages.
It is also an object of the present invention to provide new food storage cans which have been adapted to detect the presence of contaminating bacteria in food stored in cans.
It is also an object of the present invention to provide new polymeric compositions which can be incorporated onto the lining of a food can and used to detect contaminating bacteria in canned food.
These and other objects of the present invention may be readily gleaned from the description of the invention which follows.
SUMMARY OF THE INVENTION
The present invention relates to a method for determining the presence or absence of contaminating bacteria in a canned food sample comprising storing food in a can having as a lining a polymeric composition, said composition preferably being permeable to at least one gas selected from the group consisting of carbon dioxide, sulfur dioxide and ammonia gas and containing an indicator for detecting the presence or abscence of said gas; said indicator being polymerized or dispersed throughout said polymeric composition. Alternatively, the indicator may be coated onto the polymeric composition and used directly without further modification or coated in combination with or coated by a permeable polymer which helps the indicator to adhere to the first coating either in combination with the permeable polymer or underneath the permeable polymer.
The present invention also relates to novel food cans which have been lined with polymeric compositions containing an indicator which has been polymerized or dispersed throughout or coated onto the polymeric composition, the food cans being capable of storing food and detecting the presence of gas released by contaminating bacteria present in the food which is stored in the cans.
The present invention is useful for detecting bacterial contamination in food which has been stored after canning or packaging for extended periods of time. Although virtually any microorganism which produces a gas during growth and/or metabolism may be detected by the present invention, particularly important microorganisms which may be detected by the present invention include bacteria such as Salmonella sp, Streptococcus sp., Shigella sp., Botulism sp., Escherichia coli and Coliform bacteria. A number of types of E. coli may be detected by the instant invention including enterotoxigenic (ETEC), enteroinvasive (EIEC), enterohemorrhagic (EHEC), enteropathogenic (EPEC) and enteradherent (EAEC), among others.
Numerous polymeric compositions for lining the food storage package may be used, with preferred compositions including polymeric compositions which are sufficiently permeable to allow gas produced by contaminating bacteria to diffuse through the composition to a reactive site on an indicator dispersed or polymerized throughout the composition without allowing the food stored within the package to leak or come into contact with a package lining to be avoided, such as the steel lining of a food can.
Indicators include those which are well known in the art. The indicators which find use in the present invention are those which provide a calorimetric reaction upon exposure to the gases produced by contaminating microorganisms. Gases which are produced by contaminating microorganisms include, for example, carbon dioxide, sulfur dioxide and ammonia. Each of these gases in water produces an acid (carbonic, sulfuric) or a base (ammonia) which reacts with the chosen indicator to produce a calorimetric reaction, thus indicating the presence or absence (in the case where no reaction occurs) of contaminating bacteria.
DETAILED DESCRIPTION OF THE INVENTION
The following terms will be used throughout the specification to describe the present invention.
The term "polymeric composition" is used to describe the chemical lining of the food storage containers or plastic wrap according the present invention which contains indicator, whether polymerized or dispersed within the composition or coated onto the composition. Polymeric compositions for use in the present invention include those which are typically used to line cans or make food wrap, for example, polyvinyl acetate, polyvinylchloride copolymers of polyvinylacetate and polyvinylchloride and hydroxyl-modified vinyl chloride/vinyl acetate copolymers (for example, vinyl VAGH and VyHH copolymers available from Union Carbide). Additional, preferred polymers include those which are permeable to one or more of carbon dioxide, sulfur dioxide or ammonia gas produced by the contaminating bacteria. Additional exemplary polymeric compositions for use in the present invention include for example, polyethylene, polystyrene, polytertiarybutylstyrene, cellulose acetate butyrate, polytetrafluoroethylene, polytetrafluoroethylene/hexafluoropropene copolymers (Teflon FEP), butadiene/styrene copolymers, butadiene/methylstyrene copolymers, poly(meth)acrylates, butadiene/acrylonitrile copolymers, ethylene/propylene copolymers, polybutadiene, polyisoprene, polyester resins, poly(imino(1-oxohexamethylene) (Nylon 6), poly(imino(l-oxoundecamethylene) (Nylon 11), poly(oxy2,6-dimethyl-1,4-phenylene), poly(oxycarbonyloxy-1,4- 1,4phenyleneisopropylidene-1,4-phenylene) (Lexan), cellulose acetate, ethyl cellulose, polyethylene terephthalate and mixtures, thereof, among others.
The polymeric compositions may be hydrophilic or hydrophobic, but preferably, are hydrophobic in order to minimize the likelihood that the food or water in the food will come into contact with the metal lining of the storage can or the composition will absorb significant quantities of water from the food. In certain cases, for example, when carbon dioxide or sulfur dioxide is to be analyzed, it may be advantageous to have the polymeric composition accommodate or contain small amounts of water, in order to allow the formation of carbonic acid or sulfuric acid, which will be directly detected by the indicators included in the polymeric compositions.
The polymeric composition may line a food package, e.g., a steel can, in a manner to form a "tight coating", i.e., a coating which is designed to preclude any part of the stored food from coming into contact with the underlying can. The polymeric composition may be chosen so as to allow gases to pass through and come into contact with an indicator which has been polymerized or dispersed throughout the polymeric composition. Alternatively, the indicator may be coated onto the polymeric composition and used directly or coated onto the underlying polymeric composition in combination with or underneath a gas permeable polymer which holds the indicator in place for analysis.
One of ordinary skill in the art, simply relying on readily available information regarding the permeability data (for individual gases such as carbon dioxide, sulfur dioxide and ammonia) for the various polymeric compositions and the relative degree of hydrophobicity or hydrophilicity may easily determine the appropriate polymeric composition to use in a particular manner with a particular foodstuff. Thus, one of ordinary skill in the art may choose the appropriate polymeric composition to line the food container, or accommodate an effective amount of indicator based upon the food to be stored as well as a microorganism or bacteria to be detected. For example, in the case of detecting E. coli contamination in cans, one of ordinary skill in the art will recognize that it is appropriate to choose polymers containing an indicator which detects trace quantities of carbon dioxide produced by the bacteria. In the case of other bacteria and foodstuffs, the polymeric composition will be modified to accommodate the appropriate indicator and food.
The term "gas" is used to describe gaseous products of metabolism or growth of contaminating bacteria in food which is stored in the storage cans according to the present invention. Exemplary gases which are detected in the present invention include carbon dioxide, sulfur dioxide and ammonia, among others.
The term "permeable" is used to describe polymeric compositions according to the present invention which allow sufficient quantities of gases to flow through the composition and interact or react with the indicator.
The term "package" is used to describe any container, can, pail, bottle, drum, packing material or wrap in which food may be stored. In the present invention the food package is lined with a polymeric composition which contains or is coated by an indicator. The indicator, where it is coated onto a composition may be further coated with an additional polymeric composition, preferably permeable to the gas or gases to be detected.
The term "contaminating bacteria" is used to describe microorganisms such as bacteria which, if present in food, create a potential health hazard for the consumer. Life-threatening sickness, even death, may result from the consumption of food contaminated with any number of deleterious microorganisms such as bacteria. Although numerous contaminating microoraganisms including bacteria may be detected using the present invention, the most common bacteria which create health problems in food include Salmonella sp., Streptococcus sp., Shigella sp., Botulism sp., Escherichia coli and other Coliform bacteria. In the case of Escherichia coli, a number of types may be problematic, but are detected by the present invention including, for example, enterotoxigenic (ETEC), enteroinvasive (EIEC), enterohemorrhagic (EHEC), enteropathogenic (EPEC) and enteradherent (EAEC), among others. Numerous E. coli of O-serogroups may be problematic including for example, (EPEC) 026:K60, 055:K59, 0111:L58, 0127:K63, 086:K61, 0119:K69, 0124:K72, 0125:K70, 0126:K71, 0128:K67, 018:K77, 020:K61, 020:K84, 028:K73, 044:K74, 0112:K66; (ETEC) 06, 08, 011, 078; (EIEC) 028:K73, 0112:K66, 0124:K72, 0143:K b , 0144:K c ; and (EHEC) 0157:H7, among others. A particularly onerous serogroup of E. coli is (EHEC) 0157:H7.
The above-referenced bacteria, among others, as a consequence of growth and/or metabolism, produce significant quantities of gas including carbon dioxide, sulfur dioxide or ammonia gas, among others. The gases produced by these deleterious microorganisms may be readily detected using the present invention, thus alerting the consumer to the potential dangers of consuming contaminated food.
The bacteria generally remain dormant as spores in the food product until certain conditions exist. The most prevalent condition is a constant exposure to ambient temperatures of about 45.5° C.+2° C. outside the can, which promotes growth and germination of the bacterial spore. As the bacterial spore grows it releases an effervescent gas, which migrates toward the indicator and produces a chemical reaction.
The term "indicator" is used to describe chemical compounds which may be added to or coated onto polymeric compositions according to the present invention in amounts effective to detect gases which are produced by contaminating bacteria in food. Indicators are chemical compounds which undergo a chemical reaction in the presence of a gas or an acid or base conjugate of a gas and produce a calorimetric species in response to the acid or base produced. The chemical response of the indicator is generally concentration dependent. Indicators for use in the present invention may be solids or liquids. In the present invention, gases which are produced by contaminating bacteria including carbon dioxide, sulfur dioxide and ammonia gas, among others, react with the chosen indicator which has been polymerized or dispersed throughout the polymeric composition. The indicator produces a calorimetric reaction upon exposure to the gas or an acid or base conjugate of the gas, thus evidencing the presence of contaminating bacteria in the analyzed food sample. In certain preferred versions of the present invention, the indicator will produce an irreversible calorimetric reaction upon exposure to the gas produced by the contaminating bacteria, thus minimizing the possibility that leakage of the gas from the food storage container will result in a failure to detect contamination.
Exemplary indicators for the detection of carbon dioxide or sulfur dioxide include, for example, xylenol blue (p-Xylenolsulfonephthalein), bromocresol purple (5',55"-Dibromo-o-cresolsulfonephthalein), bromocresol green (Tetrabromo-m-cresolsulfonephthalein), cresol red (o-Cresolsulfonephthalein), phenolphthalein, bromothymol blue (3',3"-Dibromothymolsulfonephthalein), p-naphtholbenzein (4- alpha-(4-Hydroxy-1-naphthyl)benzylidene!-1(4H)-naphthalenone) and neutral red (3-Amino-7-dimethylamino-2-methylphenazine Chloride), among others. These indicators all provide calorimetric responses to the addition of quanities of acid, in the form of carbonic acid or sulfuric acid (from CO 2 or H 2 SO 4 production by contaminating bacteria). An exemplary indicator for the detection of ammonia produced by contaminating bacteria comprises a mixture of potassium iodide, mercuric (III) iodide, sodium borate, sodium hydroxide and water (in the ratio of 1.5:2.5:2.5:3.5:90 parts by weight).
Indicators which are advantageouusly employed in the present invention may be dispersed or polymerized throughout the polymeric composition or alternatively, simply coated onto the polymeric composition (lining of the food package). In the case of indicators which are polymerized throughout the polymeric composition, the indicators may be modified and placed in monomeric form in order to participate in the polymerization reaction and become part of a backbone or sidechain of the polymeric composition.
The present invention may be used in standard food cans or alternatively, may be used in other packing materials, such as plastic bags (especially in the case of sea food), saran wrap or cellophane or moisture barrier packing (in the case of storing meats, cheese, poultry, etc.).
In one aspect, the present invention is essentially a warning system for the presence of certain contaminants within containers of processed or non-processed comestibles. A positive analysis will alert a consumer to avoid eating contaminated food.
The uniqueness of this invention is manifest in the following exemplary manner:
1) The capability of ascertaining the presence or absence of contaminants within a container while the contents are in a closed and sealed atmosphere by way of an on-going, and continuous analysis procedure. 2) The container is prepared for the continuing analysis procedure during the manufacturing process where the polymeric composition containing indicator may be applied, directly onto the package or over a standard package (can) coating with a clear USDA or FDA approved indicator solution suspended or dispersed in the polymeric composition and applied by various methods to the package, e.g., sprayed, roller coated, printed, stamped, etc. The polymeric composition containing the indicator will dry, polymerize, convert or cross-link at the specification of the container fill line.
During the container manufacture procedure, the indicator solution, being clear when applied, may be printed or otherwise applied, over standard internal can coatings so as to convey a message to whomever opens the container. Exemplary messages may read:
WARNING| DO NOT EAT THE CONTENTS OF THIS CAN, or
WARNING| BEFORE EATING, THE CONTENTS OF THIS CAN MUST BE HEATED TO 150° F. FOR FIVE MINUTES, or
WARNING| DO NOT EAT, RETURN TO STORE FOR REFUND.
When applied, the indicator is still clear or a particular color which evidences that no reaction or contamination has occurred. When the food package is filled, closed and sealed, the continuing chemical analysis begins. If the food package contains contaminated toxic organic materials, these will begin to grow and multiply within the closed and sealed atmosphere, producing any one or more of carbon dioxide, sulfur dioxide or ammonia, among others during metabolic processes.
The microrganism growth particles may be spores or bacteria which produce gas as they grow and multiply. As the gas accumulates, it migrates in an upward direction to accumulate in a top end area. As the gas contacts the indicator, the indicator ink and gas react, thus causing the indicator to change from a clear or original color to a predetermined color, thus making the warning legible. If no gas is produced, there will be no reaction.
This invention may also be employed in additional applications. Employing the polymeric composition containing an indicator on the inside of a container, i.e., a can, jar lid, bottle cap, 5 gallon pail cover or 55 gallon drum lid, among other packages, the indicator or polymeric composition containing indicator may be deposited on either or both sides of "plastic wrap" sheets or rolls. With both sides of the plastic material printed, when used as a wrapper for table ready comestibles, the user applying the wrap to the food product will not be confused as to which side of the plastic wrap has been printed because the indicator is applied to both sides of the plastic wrap.
As in the instance of comestibles packaged in cans for sale to the general public or for temporary storage in large open containers in processing plants or retail markets, the organisms generate gases as they grow and multiply. The gases will migrate to the indicator and produce a calorimetric reaction, thus, preferably causing a warning to appear.
The following examples are provided to illustrate the present invention and should not be misunderstood to limit the scope of the present invention in any way.
EXAMPLE
The following is a description of the manufacturing process of a standard can that can be used in the packaging of vegetables such as corn, various kinds of beans, fruit, fruit sald, puddings, etc.
The raw material generally is a mild steel in large rolls delivered to the manufacturing site. A large roll is fed into the "slitter." The roll is then "slit" (cut), then rerolled in to various rolls, the width of which is equal to the exact height of the can in its finished state. A roll of the desired width is then painted with a vinyl paint (polyvinyl acetate or polyvinylchloride), the formula of which is compatible with the food product which is to be packaged in the finished can.
The roll is thereafter straightened and cut. The pieces are the exact size of the finsished can body. The pieces are stacked and portions of the stacks are introduced into a feeding device which is a gravity feeder inserting one body piece a time into a machine which forms the flat piece (blank) into a cylinder and passes the now cyclical "body" past an electrical resistance welder, joining the two edges together with an electrical resistance weld. The welded section is then coated with a "side seam enamel" which can tolerate the very high temperature of the welding process.
The welded cyclinder (body) moves along with the conveyer at the speed of of 400-600 can bodies per minute. The conveyor by design changes the direction of the "lie" of the can body. To this point, the can bodies have been in a horizontal position, following each other along the conveyor. They are now turned in a manner to create a side by side relationship, and then fed into a large platen with wide holes. The platen is turning in the same direction as the conveyor. As the platen turns, it takes the cans out of the conveyor line, the inside of the can is sprayed with a vinyl coating, and then the can is returned to the conveyor, the can body now moves along the conveyor a short distance. The solvent formula of the coating is adjusted to the speed of the conveyor and the distance traveled to the oven.
The body is then made. There are generally two and three piece can assemblies. Various formulas are used in the internal finish of the cans. Some have 100% solids and need no "flash off time." Other coatings may employ thermal conversion, chemical reactions or ultra violet light to ensure complete polymerization.
A two piece can involves a body made by deep draw. This method of manufacture would have a single piece deep drawn in the center of the flat stock resulting in a body with the bottom intact in a single impact referred to as a "deep draw." This can be accomplished singularly or by a multiple impact changing tools as the draw is deepened to a desired depth or height of the can. Three piece cans, the most widely-used design, involves a body, a bottom and a top.
The top and bottom of the can are both refrred to as lids, and are made from a single sheet of steel which is die cut to obtain a maximum number of lids per piece of sheet stock. Tops and bottoms are separated from the flash and they are printed with the indicator directly or along with the polymeric composition containing the indicator on the inside portion of the lids. The indicator applied will be specific for the product canned or may be formulated to be sensitive to several contaminating microorganisms.
The indicator used for a particular canning run must be compatible with the internal can coating and maintain acceptable adhesion whether the product is going to be frozen or cooked at a high temperature. Because the food product inside the can comes in contact with the food, the indicator is classified as a food additive and must meet all standards, as set forth by the FDA for food additives.
In the case of a three part can, there is a bottom, a body and a top. The bottom is attached in one of several methods to the body. The cans are filled with food product and the lid is fastened using an approved method. Some cans containing certain food products may be further processed (cooked) at this point. Other cans have fully processed food filled at the start. The filled can is now ready for labeling, packing and shipping.
During storage, if contaminant bacteria are present in the stored food, the gas produced by the bacteria will produce a reaction in the indicator in the lid (top or bottom) of the can. A color reaction will indicate the presence of deleterious quantities of bacteria, no reaction indicates the food product is safe for consumption.
Food Wrap
Generally, two types of vinyl compounds are used in food wrap, e.g., polyvinyl acetate and polyvinyl chloride. The treatment of either of these vinyl solutions is the same. The indicator, dispersed in a compatible carrier, is blended into the vinyl wrap mixture while the ingredients are in a liquid state. Both solutions together will be further processed until the liquid vinyl compound is processed into sheets, then into rolls.
When the wrap is used to cover food products and contaminant bacteria, if present, commence to grow and generate gases. When the gases reach the food wrap and contact the indicator bearing cover, the indicator will react by changing color. The absence of toxin is evidenced by no reaction.
It is to be understood that the embodiments described hereinabove are for the purposes of providing a description of the present invention by way of example and are not to be viewed as limiting the present invention in any way. Various modifications or changes that may be made to that described hereinabove by those of ordinary skill in the art are also contemplated by the present invention and are to be included within the spirit and purview of this application and the following claims. | A method for determining the presence or absence of contaminating bacteria in a packaged food sample includes storing food in a package having as a lining a polymeric composition, said composition preferably being permeable to at least one gas selected from the group consisting of carbon dioxide and sulfur dioxide and containing an indicator for detecting the presence or abscence of the gas; the indicator being polymerized or dispersed throughout the polymeric composition or coated onto the polymeric composition. | Briefly describe the main invention outlined in the provided context. | [
"This application is a continuation of application Ser.",
"No. 08/389,296, filed Feb. 16, 1995, now abandoned.",
"FIELD OF THE INVENTION This invention relates to methods for detecting the existence of harmful levels of bacterial growth in packaged foods.",
"BACKGROUND OF THE INVENTION The presence of undesirable bacteria, for example, Botulism sp.",
", among others, in food products intended for human consumption has recently caused increased concern among food product manufacturers.",
"This is due to the potential that contaminated food has for serious illness or even death as a consequence of its ingestion by the consumer.",
"While it would be desirable to monitor contamination in every sample of food, in most cases, it is simply not possible to detect the presence of contaminating bacteria by visual or other inspection.",
"Consequently, chemical means must be used to facilitate such detection.",
"Although food is generally inspected prior to its being canned, it is presently not practical to inspect each can of food for contamination.",
"OBJECTS OF THE INVENTION It is an object of the invention to provide a method for detecting the presence of contaminating bacteria in a food sample, especially a food sample which has been stored in cans or other packages.",
"It is also an object of the present invention to provide new food storage cans which have been adapted to detect the presence of contaminating bacteria in food stored in cans.",
"It is also an object of the present invention to provide new polymeric compositions which can be incorporated onto the lining of a food can and used to detect contaminating bacteria in canned food.",
"These and other objects of the present invention may be readily gleaned from the description of the invention which follows.",
"SUMMARY OF THE INVENTION The present invention relates to a method for determining the presence or absence of contaminating bacteria in a canned food sample comprising storing food in a can having as a lining a polymeric composition, said composition preferably being permeable to at least one gas selected from the group consisting of carbon dioxide, sulfur dioxide and ammonia gas and containing an indicator for detecting the presence or abscence of said gas;",
"said indicator being polymerized or dispersed throughout said polymeric composition.",
"Alternatively, the indicator may be coated onto the polymeric composition and used directly without further modification or coated in combination with or coated by a permeable polymer which helps the indicator to adhere to the first coating either in combination with the permeable polymer or underneath the permeable polymer.",
"The present invention also relates to novel food cans which have been lined with polymeric compositions containing an indicator which has been polymerized or dispersed throughout or coated onto the polymeric composition, the food cans being capable of storing food and detecting the presence of gas released by contaminating bacteria present in the food which is stored in the cans.",
"The present invention is useful for detecting bacterial contamination in food which has been stored after canning or packaging for extended periods of time.",
"Although virtually any microorganism which produces a gas during growth and/or metabolism may be detected by the present invention, particularly important microorganisms which may be detected by the present invention include bacteria such as Salmonella sp, Streptococcus sp.",
", Shigella sp.",
", Botulism sp.",
", Escherichia coli and Coliform bacteria.",
"A number of types of E. coli may be detected by the instant invention including enterotoxigenic (ETEC), enteroinvasive (EIEC), enterohemorrhagic (EHEC), enteropathogenic (EPEC) and enteradherent (EAEC), among others.",
"Numerous polymeric compositions for lining the food storage package may be used, with preferred compositions including polymeric compositions which are sufficiently permeable to allow gas produced by contaminating bacteria to diffuse through the composition to a reactive site on an indicator dispersed or polymerized throughout the composition without allowing the food stored within the package to leak or come into contact with a package lining to be avoided, such as the steel lining of a food can.",
"Indicators include those which are well known in the art.",
"The indicators which find use in the present invention are those which provide a calorimetric reaction upon exposure to the gases produced by contaminating microorganisms.",
"Gases which are produced by contaminating microorganisms include, for example, carbon dioxide, sulfur dioxide and ammonia.",
"Each of these gases in water produces an acid (carbonic, sulfuric) or a base (ammonia) which reacts with the chosen indicator to produce a calorimetric reaction, thus indicating the presence or absence (in the case where no reaction occurs) of contaminating bacteria.",
"DETAILED DESCRIPTION OF THE INVENTION The following terms will be used throughout the specification to describe the present invention.",
"The term "polymeric composition"",
"is used to describe the chemical lining of the food storage containers or plastic wrap according the present invention which contains indicator, whether polymerized or dispersed within the composition or coated onto the composition.",
"Polymeric compositions for use in the present invention include those which are typically used to line cans or make food wrap, for example, polyvinyl acetate, polyvinylchloride copolymers of polyvinylacetate and polyvinylchloride and hydroxyl-modified vinyl chloride/vinyl acetate copolymers (for example, vinyl VAGH and VyHH copolymers available from Union Carbide).",
"Additional, preferred polymers include those which are permeable to one or more of carbon dioxide, sulfur dioxide or ammonia gas produced by the contaminating bacteria.",
"Additional exemplary polymeric compositions for use in the present invention include for example, polyethylene, polystyrene, polytertiarybutylstyrene, cellulose acetate butyrate, polytetrafluoroethylene, polytetrafluoroethylene/hexafluoropropene copolymers (Teflon FEP), butadiene/styrene copolymers, butadiene/methylstyrene copolymers, poly(meth)acrylates, butadiene/acrylonitrile copolymers, ethylene/propylene copolymers, polybutadiene, polyisoprene, polyester resins, poly(imino(1-oxohexamethylene) (Nylon 6), poly(imino(l-oxoundecamethylene) (Nylon 11), poly(oxy2,6-dimethyl-1,4-phenylene), poly(oxycarbonyloxy-1,4- 1,4phenyleneisopropylidene-1,4-phenylene) (Lexan), cellulose acetate, ethyl cellulose, polyethylene terephthalate and mixtures, thereof, among others.",
"The polymeric compositions may be hydrophilic or hydrophobic, but preferably, are hydrophobic in order to minimize the likelihood that the food or water in the food will come into contact with the metal lining of the storage can or the composition will absorb significant quantities of water from the food.",
"In certain cases, for example, when carbon dioxide or sulfur dioxide is to be analyzed, it may be advantageous to have the polymeric composition accommodate or contain small amounts of water, in order to allow the formation of carbonic acid or sulfuric acid, which will be directly detected by the indicators included in the polymeric compositions.",
"The polymeric composition may line a food package, e.g., a steel can, in a manner to form a "tight coating", i.e., a coating which is designed to preclude any part of the stored food from coming into contact with the underlying can.",
"The polymeric composition may be chosen so as to allow gases to pass through and come into contact with an indicator which has been polymerized or dispersed throughout the polymeric composition.",
"Alternatively, the indicator may be coated onto the polymeric composition and used directly or coated onto the underlying polymeric composition in combination with or underneath a gas permeable polymer which holds the indicator in place for analysis.",
"One of ordinary skill in the art, simply relying on readily available information regarding the permeability data (for individual gases such as carbon dioxide, sulfur dioxide and ammonia) for the various polymeric compositions and the relative degree of hydrophobicity or hydrophilicity may easily determine the appropriate polymeric composition to use in a particular manner with a particular foodstuff.",
"Thus, one of ordinary skill in the art may choose the appropriate polymeric composition to line the food container, or accommodate an effective amount of indicator based upon the food to be stored as well as a microorganism or bacteria to be detected.",
"For example, in the case of detecting E. coli contamination in cans, one of ordinary skill in the art will recognize that it is appropriate to choose polymers containing an indicator which detects trace quantities of carbon dioxide produced by the bacteria.",
"In the case of other bacteria and foodstuffs, the polymeric composition will be modified to accommodate the appropriate indicator and food.",
"The term "gas"",
"is used to describe gaseous products of metabolism or growth of contaminating bacteria in food which is stored in the storage cans according to the present invention.",
"Exemplary gases which are detected in the present invention include carbon dioxide, sulfur dioxide and ammonia, among others.",
"The term "permeable"",
"is used to describe polymeric compositions according to the present invention which allow sufficient quantities of gases to flow through the composition and interact or react with the indicator.",
"The term "package"",
"is used to describe any container, can, pail, bottle, drum, packing material or wrap in which food may be stored.",
"In the present invention the food package is lined with a polymeric composition which contains or is coated by an indicator.",
"The indicator, where it is coated onto a composition may be further coated with an additional polymeric composition, preferably permeable to the gas or gases to be detected.",
"The term "contaminating bacteria"",
"is used to describe microorganisms such as bacteria which, if present in food, create a potential health hazard for the consumer.",
"Life-threatening sickness, even death, may result from the consumption of food contaminated with any number of deleterious microorganisms such as bacteria.",
"Although numerous contaminating microoraganisms including bacteria may be detected using the present invention, the most common bacteria which create health problems in food include Salmonella sp.",
", Streptococcus sp.",
", Shigella sp.",
", Botulism sp.",
", Escherichia coli and other Coliform bacteria.",
"In the case of Escherichia coli, a number of types may be problematic, but are detected by the present invention including, for example, enterotoxigenic (ETEC), enteroinvasive (EIEC), enterohemorrhagic (EHEC), enteropathogenic (EPEC) and enteradherent (EAEC), among others.",
"Numerous E. coli of O-serogroups may be problematic including for example, (EPEC) 026:K60, 055:K59, 0111:L58, 0127:K63, 086:K61, 0119:K69, 0124:K72, 0125:K70, 0126:K71, 0128:K67, 018:K77, 020:K61, 020:K84, 028:K73, 044:K74, 0112:K66;",
"(ETEC) 06, 08, 011, 078;",
"(EIEC) 028:K73, 0112:K66, 0124:K72, 0143:K b , 0144:K c ;",
"and (EHEC) 0157:H7, among others.",
"A particularly onerous serogroup of E. coli is (EHEC) 0157:H7.",
"The above-referenced bacteria, among others, as a consequence of growth and/or metabolism, produce significant quantities of gas including carbon dioxide, sulfur dioxide or ammonia gas, among others.",
"The gases produced by these deleterious microorganisms may be readily detected using the present invention, thus alerting the consumer to the potential dangers of consuming contaminated food.",
"The bacteria generally remain dormant as spores in the food product until certain conditions exist.",
"The most prevalent condition is a constant exposure to ambient temperatures of about 45.5° C.+2° C. outside the can, which promotes growth and germination of the bacterial spore.",
"As the bacterial spore grows it releases an effervescent gas, which migrates toward the indicator and produces a chemical reaction.",
"The term "indicator"",
"is used to describe chemical compounds which may be added to or coated onto polymeric compositions according to the present invention in amounts effective to detect gases which are produced by contaminating bacteria in food.",
"Indicators are chemical compounds which undergo a chemical reaction in the presence of a gas or an acid or base conjugate of a gas and produce a calorimetric species in response to the acid or base produced.",
"The chemical response of the indicator is generally concentration dependent.",
"Indicators for use in the present invention may be solids or liquids.",
"In the present invention, gases which are produced by contaminating bacteria including carbon dioxide, sulfur dioxide and ammonia gas, among others, react with the chosen indicator which has been polymerized or dispersed throughout the polymeric composition.",
"The indicator produces a calorimetric reaction upon exposure to the gas or an acid or base conjugate of the gas, thus evidencing the presence of contaminating bacteria in the analyzed food sample.",
"In certain preferred versions of the present invention, the indicator will produce an irreversible calorimetric reaction upon exposure to the gas produced by the contaminating bacteria, thus minimizing the possibility that leakage of the gas from the food storage container will result in a failure to detect contamination.",
"Exemplary indicators for the detection of carbon dioxide or sulfur dioxide include, for example, xylenol blue (p-Xylenolsulfonephthalein), bromocresol purple (5',55"-Dibromo-o-cresolsulfonephthalein), bromocresol green (Tetrabromo-m-cresolsulfonephthalein), cresol red (o-Cresolsulfonephthalein), phenolphthalein, bromothymol blue (3',3"-Dibromothymolsulfonephthalein), p-naphtholbenzein (4- alpha-(4-Hydroxy-1-naphthyl)benzylidene!",
"-1(4H)-naphthalenone) and neutral red (3-Amino-7-dimethylamino-2-methylphenazine Chloride), among others.",
"These indicators all provide calorimetric responses to the addition of quanities of acid, in the form of carbonic acid or sulfuric acid (from CO 2 or H 2 SO 4 production by contaminating bacteria).",
"An exemplary indicator for the detection of ammonia produced by contaminating bacteria comprises a mixture of potassium iodide, mercuric (III) iodide, sodium borate, sodium hydroxide and water (in the ratio of 1.5:2.5:2.5:3.5:90 parts by weight).",
"Indicators which are advantageouusly employed in the present invention may be dispersed or polymerized throughout the polymeric composition or alternatively, simply coated onto the polymeric composition (lining of the food package).",
"In the case of indicators which are polymerized throughout the polymeric composition, the indicators may be modified and placed in monomeric form in order to participate in the polymerization reaction and become part of a backbone or sidechain of the polymeric composition.",
"The present invention may be used in standard food cans or alternatively, may be used in other packing materials, such as plastic bags (especially in the case of sea food), saran wrap or cellophane or moisture barrier packing (in the case of storing meats, cheese, poultry, etc.).",
"In one aspect, the present invention is essentially a warning system for the presence of certain contaminants within containers of processed or non-processed comestibles.",
"A positive analysis will alert a consumer to avoid eating contaminated food.",
"The uniqueness of this invention is manifest in the following exemplary manner: 1) The capability of ascertaining the presence or absence of contaminants within a container while the contents are in a closed and sealed atmosphere by way of an on-going, and continuous analysis procedure.",
"2) The container is prepared for the continuing analysis procedure during the manufacturing process where the polymeric composition containing indicator may be applied, directly onto the package or over a standard package (can) coating with a clear USDA or FDA approved indicator solution suspended or dispersed in the polymeric composition and applied by various methods to the package, e.g., sprayed, roller coated, printed, stamped, etc.",
"The polymeric composition containing the indicator will dry, polymerize, convert or cross-link at the specification of the container fill line.",
"During the container manufacture procedure, the indicator solution, being clear when applied, may be printed or otherwise applied, over standard internal can coatings so as to convey a message to whomever opens the container.",
"Exemplary messages may read: WARNING| DO NOT EAT THE CONTENTS OF THIS CAN, or WARNING| BEFORE EATING, THE CONTENTS OF THIS CAN MUST BE HEATED TO 150° F. FOR FIVE MINUTES, or WARNING| DO NOT EAT, RETURN TO STORE FOR REFUND.",
"When applied, the indicator is still clear or a particular color which evidences that no reaction or contamination has occurred.",
"When the food package is filled, closed and sealed, the continuing chemical analysis begins.",
"If the food package contains contaminated toxic organic materials, these will begin to grow and multiply within the closed and sealed atmosphere, producing any one or more of carbon dioxide, sulfur dioxide or ammonia, among others during metabolic processes.",
"The microrganism growth particles may be spores or bacteria which produce gas as they grow and multiply.",
"As the gas accumulates, it migrates in an upward direction to accumulate in a top end area.",
"As the gas contacts the indicator, the indicator ink and gas react, thus causing the indicator to change from a clear or original color to a predetermined color, thus making the warning legible.",
"If no gas is produced, there will be no reaction.",
"This invention may also be employed in additional applications.",
"Employing the polymeric composition containing an indicator on the inside of a container, i.e., a can, jar lid, bottle cap, 5 gallon pail cover or 55 gallon drum lid, among other packages, the indicator or polymeric composition containing indicator may be deposited on either or both sides of "plastic wrap"",
"sheets or rolls.",
"With both sides of the plastic material printed, when used as a wrapper for table ready comestibles, the user applying the wrap to the food product will not be confused as to which side of the plastic wrap has been printed because the indicator is applied to both sides of the plastic wrap.",
"As in the instance of comestibles packaged in cans for sale to the general public or for temporary storage in large open containers in processing plants or retail markets, the organisms generate gases as they grow and multiply.",
"The gases will migrate to the indicator and produce a calorimetric reaction, thus, preferably causing a warning to appear.",
"The following examples are provided to illustrate the present invention and should not be misunderstood to limit the scope of the present invention in any way.",
"EXAMPLE The following is a description of the manufacturing process of a standard can that can be used in the packaging of vegetables such as corn, various kinds of beans, fruit, fruit sald, puddings, etc.",
"The raw material generally is a mild steel in large rolls delivered to the manufacturing site.",
"A large roll is fed into the "slitter.",
""",
"The roll is then "slit"",
"(cut), then rerolled in to various rolls, the width of which is equal to the exact height of the can in its finished state.",
"A roll of the desired width is then painted with a vinyl paint (polyvinyl acetate or polyvinylchloride), the formula of which is compatible with the food product which is to be packaged in the finished can.",
"The roll is thereafter straightened and cut.",
"The pieces are the exact size of the finsished can body.",
"The pieces are stacked and portions of the stacks are introduced into a feeding device which is a gravity feeder inserting one body piece a time into a machine which forms the flat piece (blank) into a cylinder and passes the now cyclical "body"",
"past an electrical resistance welder, joining the two edges together with an electrical resistance weld.",
"The welded section is then coated with a "side seam enamel"",
"which can tolerate the very high temperature of the welding process.",
"The welded cyclinder (body) moves along with the conveyer at the speed of of 400-600 can bodies per minute.",
"The conveyor by design changes the direction of the "lie"",
"of the can body.",
"To this point, the can bodies have been in a horizontal position, following each other along the conveyor.",
"They are now turned in a manner to create a side by side relationship, and then fed into a large platen with wide holes.",
"The platen is turning in the same direction as the conveyor.",
"As the platen turns, it takes the cans out of the conveyor line, the inside of the can is sprayed with a vinyl coating, and then the can is returned to the conveyor, the can body now moves along the conveyor a short distance.",
"The solvent formula of the coating is adjusted to the speed of the conveyor and the distance traveled to the oven.",
"The body is then made.",
"There are generally two and three piece can assemblies.",
"Various formulas are used in the internal finish of the cans.",
"Some have 100% solids and need no "flash off time.",
""",
"Other coatings may employ thermal conversion, chemical reactions or ultra violet light to ensure complete polymerization.",
"A two piece can involves a body made by deep draw.",
"This method of manufacture would have a single piece deep drawn in the center of the flat stock resulting in a body with the bottom intact in a single impact referred to as a "deep draw.",
""",
"This can be accomplished singularly or by a multiple impact changing tools as the draw is deepened to a desired depth or height of the can.",
"Three piece cans, the most widely-used design, involves a body, a bottom and a top.",
"The top and bottom of the can are both refrred to as lids, and are made from a single sheet of steel which is die cut to obtain a maximum number of lids per piece of sheet stock.",
"Tops and bottoms are separated from the flash and they are printed with the indicator directly or along with the polymeric composition containing the indicator on the inside portion of the lids.",
"The indicator applied will be specific for the product canned or may be formulated to be sensitive to several contaminating microorganisms.",
"The indicator used for a particular canning run must be compatible with the internal can coating and maintain acceptable adhesion whether the product is going to be frozen or cooked at a high temperature.",
"Because the food product inside the can comes in contact with the food, the indicator is classified as a food additive and must meet all standards, as set forth by the FDA for food additives.",
"In the case of a three part can, there is a bottom, a body and a top.",
"The bottom is attached in one of several methods to the body.",
"The cans are filled with food product and the lid is fastened using an approved method.",
"Some cans containing certain food products may be further processed (cooked) at this point.",
"Other cans have fully processed food filled at the start.",
"The filled can is now ready for labeling, packing and shipping.",
"During storage, if contaminant bacteria are present in the stored food, the gas produced by the bacteria will produce a reaction in the indicator in the lid (top or bottom) of the can.",
"A color reaction will indicate the presence of deleterious quantities of bacteria, no reaction indicates the food product is safe for consumption.",
"Food Wrap Generally, two types of vinyl compounds are used in food wrap, e.g., polyvinyl acetate and polyvinyl chloride.",
"The treatment of either of these vinyl solutions is the same.",
"The indicator, dispersed in a compatible carrier, is blended into the vinyl wrap mixture while the ingredients are in a liquid state.",
"Both solutions together will be further processed until the liquid vinyl compound is processed into sheets, then into rolls.",
"When the wrap is used to cover food products and contaminant bacteria, if present, commence to grow and generate gases.",
"When the gases reach the food wrap and contact the indicator bearing cover, the indicator will react by changing color.",
"The absence of toxin is evidenced by no reaction.",
"It is to be understood that the embodiments described hereinabove are for the purposes of providing a description of the present invention by way of example and are not to be viewed as limiting the present invention in any way.",
"Various modifications or changes that may be made to that described hereinabove by those of ordinary skill in the art are also contemplated by the present invention and are to be included within the spirit and purview of this application and the following claims."
] |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an etching agent, an electronic device and a method of manufacturing an electronic device. More particularly, the present invention relates to an etching agent, and a method of manufacturing an electronic device using the etching agent, which permits batch etching of a multi-layer film comprising a conductor layer and a semiconductor layer using the same etching agent. The present invention further relates to an electronic device and a method of manufacturing the device in which the shapes of openings etched in a conductor layer and an ohmic contact layer are controlled so as to improve the characteristics and reliability of the electronic device.
2. Description of the Related Art
Conventional etching processes used in the production of semiconductor materials such as silicon typically employs a mixed solution of hydrofluoric acid, nitric acid and acetic acid. However, because this etching solution violently generates heat and nitrogen oxide gas, and causes degradation or separation of resist due to the nitric acid during the etching process, the formation of a precise (fine) pattern is considered difficult.
In order to solve the above problem, the inventors of the present invention developed an etching agent containing hydrofluoric acid and an oxoacid or an oxoacid salt compound (Japanese Patent Application No. 4-285338).
On the other hand, for example, in the production of an electronic device used for driving a liquid crystal display, a manufacturing method resulting in higher pattern precision and device productivity (yield) is demanded with increases in the display size and pixel density. The method of manufacturing an electronic device is described below with reference to the reverse stagger structure thin film transistor (TFT) shown in FIG. 16, as an example.
A conventional TFT is manufactured, for example, by the following method. A Cr film is first formed on a glass substrate 1600 by sputtering, and gate electrodes 1601 and gate wiring 1602 are then formed by patterning. A gate insulating film 1603 (e.g., SiNx), an i-type (un-doped) amorphous silicon (a-Si) layer 1604 and an n + -type (doped) a-Si layer 1605 are then deposited by a plasma CVD process, or a similar process.
The n + -type a-Si layer and i-type a-Si layer are etched using a HF-HNO 3 mixture to separate respective devices, and a conductor layer Al (containing 1 to 2% Si) is then formed by sputtering.
A source-drain electrode, wiring 1606, and a channel portion 1607 are then formed by etching the conductor layer Al with a phosphoric acid etching solution, and n + -type a-Si is etched with a mixture of HF and HNO 3 .
Finally, a passivation film is deposited using the plasma CVD process, and openings are formed for the gate wiring and source-drain wiring to complete the manufacture of the thin film transistor.
When a TFT is formed by the above method, separate steps of etching the conductor layer 1606 and etching the ohmic contact semiconductor layer 1605 are required. In the conventional method, after a resist pattern is formed, the conductor layer 1606 is etched with a first etching solution specifically formulated for a metal layer, and the ohmic contact layer 1605 is then etched with a second etching solution comprising HF and HNO 3 which is specifically formulated for the ohmic contact layer.
Since the conventional method uses two types of etching solutions, and washing is required between the respective etching steps, the etching process is very time consuming and thus reduces productivity. In addition, the repetition of the etching and washing steps deteriorates the adhesion of the resist deposited on the device during production, thereby easily producing defects in the resultant pattern. Moreover, when an etching barrier layer is provided between the conductor layer and the ohmic contact layer of a TFT, the use of multiple etching solutions and multiple etching a washing steps becomes an additional problem.
Further, the etching of aluminum (Al), which is a material typically used to form conductor layers, creates an additional problem because the typical Al etching solution has a high viscosity because etching remainder (un-etched Al) causes short-circuit defects, particularly in fine pattern portions of a resulting electronic device.
The conventional method shown in FIG. 16 also causes side etching of the ohmic contact layer, and thus forms a gap 1701 due to etching of the ohmic contact layer below the exposed edge of the conductor layer, as shown in FIG. 17(a).
The TFT frequently comprises a conductor layer formed on top of a barrier layer (for example, tungsten (W)) whose purpose is to prevent the diffusion of Al. When a barrier layer is used, a gap 1702 is typically produced between the W layer and an exposed edge of the n + -type a-Si ohmic contact layer, as shown in FIG. 17(b).
Although it is commonly known that the gaps 1701 and 1702 are produced during etching of a multi-layer film, substantially no attention has been paid to the effect of these gaps on the characteristics of a device. However, during the development of an electronic device having high density and excellent characteristics, the inventors of the present invention found that the degree of precision produced by the conventional manufacturing method is limited, and that the cause of this limit is related to the above-mentioned gaps. Namely, there are definite relationship between the gaps and the characteristics of a TFT device, variations in the characteristics between various TFT devices, and the reliability of the TFT devices. That is, the formation of a small gap deteriorates the characteristics of a device, increases variation in characteristics and deteriorates the reliability of the device.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an etching agent which enables the continuous formation of a fine pattern in a multi-layer structure including a conductor layer, a semiconductor layer, etc. by using a single etching solution.
Another object of the present invention is to provide an electronic device having excellent characteristics, fewer performance variations and excellent reliability.
A further object of the present invention is to provide an electronic device manufacturing method in which electronic devices can be generated using a short manufacturing process which produces a high yield.
In accordance with a first aspect of the present invention, an etching agent contains, in a solution, 0.05 to 0.5 mol/l of hydrofluoric acid and at least 0.01 mol/l of halooxoacid ions represented by the formula (XO n ) p - wherein X is a halogen element, n is 3, 4 or 6, and p is 1, 2 or 3.
In accordance with a second aspect of the present invention, an etching agent contains, in a solution, hydrofluoric acid, halooxoacid ions represented by the formula XO n ) p- wherein X is a halogen element, n is 3, 4 or 6, and p is 1, 2 or 3, and a halogen precipitation inhibitor.
In accordance with a third aspect of the present invention, an electronic device comprises a multi-layer film having a semiconductor layer, an ohmic contact layer and a conductor layer, wherein openings are respectively formed in portions of the ohmic contact layer and the conductor layer, and a passivation film is formed within a predetermined region including the openings, a width of an opening formed in the conductive layer being larger than a width of an adjoining opening formed in the ohmic contact layer.
In accordance with a fourth aspect of the present invention, an electronic device manufacturing method comprises successively laminating a semiconductor layer, an ohmic contact layer and a conductor layer to form a multi-layer film, forming openings by continuously removing portions of the conductor layer and the ohmic contact layer using an etching solution which etches both the conductor layer and the ohmic contact layer during a single etching step, wherein the etching solution etches the conductor layer at a higher etching rate than the ohmic contact layer, and then forming a passivation film in a predetermined region including the openings.
In accordance with a fifth aspect of the present invention, an electronic device manufacturing method comprises continuously etching an ohmic contact layer and a conductor layer, which are laminated on the surface of a semiconductor layer, using an etching agent containing, in a solution, 0.05 to 0.5 mol/l of hydrofluoric acid and at least 0.01 mol/l of halooxoacid ion represented by the formula (XO n ) p- wherein X is a halogen element, n is 3, 4 or 6, and p is 1, 2 or 3.
During experimentation to determine new manufacturing processes for increasing the efficiency and yield of electronic devices, and for shortening the manufacturing process, the inventors found that an etching solution containing hydrofluoric acid and halooxoacid ions at appropriate concentrations is capable of etching semiconductors, various metals, alloys and metallic compounds such as silicides and the like to form a fine pattern.
The inventors believe one possible mechanism of the etching process is that the halooxoacid ions, serving as a strong oxidizing agent, oxidize a solid surface of a semiconductor, a metal or the like, and then the hydrofluoric acid dissolves the thus-produced oxide. For a metal such as aluminum (Al) or the like which reacts with hydrofluoric acid, therefore, when the above-mentioned etching solution is used, oxidation with halooxoacid ions preferentially proceeds, and the generation of gas due to direct reaction between a metal and hydrofluoric acid is thus inhibited, thereby permitting stable etching.
In other words, the use of the etching agent of the present invention prevents the violent generation of heat and gases in reaction with a semiconductor, a metal or a metallic compound, and thus enables the formation of a fine pattern in a semiconductor, metal or the like. Also, because resist reacts very stably to the etching agent, side etching of the resist, which can result in a deterioration in the adhesion of the resist or separation thereof, is inhibited, thereby permitting the formation of a fine pattern. Further, since the etching agent of the present invention is chemically stable, the etching agent is capable of stable etching for a long period of time and therefore provides a cost advantage, as compared with conventional etching agents.
It is thus possible to stably form a fine pattern in a multi-layer laminated structure comprising a metal layer, a metallic compound layer and a semiconductor layer by using the same etching agent. The metal layer and semiconductor layer may have a multi-layer structure comprising at least two layers, so long as the etching agent of the present invention can be applied.
The etching agent of the present invention preferably contains 0.05 to 0.5 mol/l of hydrofluoric acid and 0.01 mol/l of halooxoacid ions. If the concentration of hydrofluoric acid exceeds 0.5 mol/l, variations in the etching process occur easily due to the direct reaction between a metal and hydrofluoric acid. Because these variations affect the semiconductor layer which serves as a ground layer, and adversely affect the characteristics of a device, the concentration of hydrofluoric acid is preferably less than 0.5 mol/l. This is because, while etching an amorphous thin film transistor having an ohmic contact layer which is several tens of nm thick and a conductor layer which is several hundred nm thick, both of which being formed on an i-type Si layer, if the concentration of hydrofluoric acid over 0.5 mol/l, then the etching rate is significantly decreased in the direction of depth, thereby causing difficulties in reliably obtaining a desired end point.
The concentration range of hydrofluoric acid depends upon the concentration of oxoacid ions, but it is more preferably 0.33 mol/l or less. Within this range, the generation of bubbles due to the direct reaction between hydrofluoric acid and a metal is further inhibited, and more uniform etching thus becomes possible. On the other hand, a concentration lower than 0.05 mol/l significantly decreases the etching rates of the semiconductor layer and the conductor layer, and is this undesirable for practical use.
The etching agent of the present invention preferably contains halooxoacid ions at a concentration of 0.01 mol/l or more, more preferably 0.02 mol/l or more, and most preferably 0.04 mol/l or more. This is because, at a concentration lower than 0.01 mol/l, although reasons are not well understood, abnormal etching easily occurs in which a portion around the etched portion of the semiconductor layer is extremely etched. Within the region of low concentrations of halooxoacid ions, the ratio of the direct reaction between a metal such as Al or the like and hydrofluoric acid to the reaction including oxidation of Al with halooxoacid ions and dissolution of the produced oxide with hydrofluoric acid is increased, as described above. It is thus preferable for uniform etching that the concentration of halooxoacid ions is 0.02 mol/l or more, and more preferably 0.04 mol/l or more.
At a high concentration of halooxoacid ions, the etching rate is decreased, and halogen material such as iodine (I) or the like is precipitated due to the etching reaction. Therefore, the upper limit of the concentration of halooxoacid ions is appropriately determined in accordance with a design of an etched device (the thicknesses of the semiconductor layer and the conductor layer, etc.) or in consideration of a balance with iodine ions for preventing precipitation of halogen material or the concentration of an organic solvent.
The halooxoacid ions used in the present invention can be obtained by dissolving halooxoacid or halooxoacid salt in water. Examples of halooxoacids or halooxoacid salt compounds include bromic acid (HBrO 3 ), potassium bromate (KBrO 3 ), sodium bromate (NaBrO 3 ), ammonium bromate (NH 4 BrO 3 ), calcium bromate (Ca(BrO 3 ) 2 ), magnesium bromate (Mg(Bro 3 ) 2 ), aluminum bromate (Al(BrO 3 ) 3 ), perbromic acid (HBrO 4 ), lithium perbromate (LiBrO 4 ), potassium perbromate (KBrO 4 ), iodic acid (HIO 3 ), potassium iodate (KIO 3 ), sodium iodate (NaIO 3 ), ammonium iodate (NH 4 IO 3 ), calcium iodate (Ca(IO 3 ) 2 ), magnesium iodate (Mg(IO 3 ) 2 ), aluminum iodate (Al(IO 3 ) 3 ), periodic acid (HIO 4 ), lithium periodate (LiIO 4 ), potassium periodate (KIO 4 ) and the like. Of these compounds, iodic acid (HIO 3 ), potassium iodate (KIO 3 ) and potassium bromate (KBrO 3 ) are easiest to handle and are thus preferable. Because iodic acid (HIO 3 ) does not contain a metal element which could possibly act as a contamination source for a semiconductor material, it is believed to be optimal for use in an etching agent for a semiconductor device which is a representative electronic device.
The etching agent of the present invention preferably contains iodine ions. The addition of iodine ions changes iodine (I 2 ) generated by etching into I 3 - which dissolves the agent, thereby preventing the precipitation of halogen. NH 4 I, KI, NaI or the like is preferably used as an iodine ion source. It is thus possible to prevent etching defects in the precipitation portion and perform a uniform and stable etching process.
The etching agent of the present invention also preferably contains a water-soluble organic solvent such as alcohol, carboxylic acid or the like. Examples of alcohols include methanol, ethanol, isopropyl alcohol, propanol, butanol, ethylene glycol, propanediol, butanediol, glycerin and the like. Examples of organic acids include acetic acid, propionic acid and the like. The addition of the organic solvent permits more uniform and stable etching due to the dissolution of the produced halogen such as iodine, and can inhibit variations of the etching depth in a substrate. In the present invention, acetic acid, methanol or ethanol is preferable. However, if the concentration of the organic solvent exceeds by 70% by volume, since the resist is corroded with the organic solvent, the concentration is preferably 70% by volume or less.
Even if the etching agent of the present invention has a composition other than the above preferable composition (0.05 to 0.5 mol/l hydrofluoric acid, 0.01 mol/l or more halooxoacid ions), the addition of a halogen precipitation inhibitor can prevent an etching defect in the precipitation portion caused by halogen precipitation, and further improve the uniformity of etching.
Iodine ion or a water-soluble organic solvent is preferably used as the halogen precipitation inhibitor. Particularly, NH 4 I, KI, NaI or the like is preferably used as an iodine ion source. As a water-soluble organic solvent, an alcohol such as methanol, ethanol, isopropyl alcohol, propanol, butanol, ethylene glycol, propanediol, butanediol, glycerin or the like, a carboxylic acid such as acetic acid, propionic acid or the like is preferably used. Of these organic solvents, acetic acid, methanol or ethanol are preferred.
As described above, the present invention has been achieved based on the findings of the inventors that, during the etching process, the gap formed between the semiconductor layer and the ohmic contact layer significantly affects the characteristics of an electronic device, variations in the characteristics and the reliability of the device.
A deterioration in the characteristics and reliability of an electronic device caused by the gap between the conductor layer and the ohmic contact layer are possibly caused by the following phenomenon: If such a gap is formed, a passivation film typically cannot be formed in the gap, and even if the passivation film is formed in the gap, only a rough film with low denseness is formed, and thus the device is liable to deteriorate.
Measurement using an energy dispersive X-ray micro-analyzer indicated that the passivation film formed in the gap contained large amounts of impurities such as oxygen, etc. This is possibly due to the position and thinness of the gap, thereby preventing complete removal of the etching solution located in the gap by a cleaning fluid, or preventing the cleaning fluid and etching solution from being completely removed from the gap during a subsequent drying process.
The impurities contaminate the channel portion when the passivation film is deposited, and thus deteriorate the device characteristics such as carrier mobility, etc. These impurities can also diffuse into the channel portion over time, after the passivation film is deposited, and thus deteriorate the characteristics of the device.
On the other hand, in the electronic device of the present invention, the ohmic contact layer and the conductor layer are continuously etched in a batch manner using an etching solution which causes a higher etching rate of the conductor layer than that of the ohmic contact layer. It is thus possible to make the width of the opening in the conductor layer greater than that of the ohmic contact layer, and thereby to prevent the formation of a gap between both layers. As a result, the entire opening surface can be covered with a dense passivation film, thereby obtaining an electronic device having high reliability. It is also possible to prevent the etching solution or the cleaning fluid from becoming trapped in the gap, and thus inhibits contamination from residual liquids. The resultant electronic device exhibits excellent characteristics such as carrier mobility, etc., and does not exhibit variations thereof, and thus the yield of electronic devices is significantly improved.
It is preferable to inhibit the formation of these gaps by using an etching solution containing at least 0.05 to 0.33 mol/l of hydrofluoric acid and 0.1 mol/l or more of halooxoacid ions. The concentration of hydrofluoric acid is more preferably 0.05 to 0.2 mol/l. Within this composition range, the etching rate of the conductor layer is greater than that of the ohmic contact layer, and control over the etching process is improved, thereby providing a reliably reproducible etching process. This also allows for finer (more precise) etching which can be stably performed.
The concentration of halooxoacid ions is more preferably at least 0.02 mol/l, most preferably at least 0.04 mol/l. This is because, at a concentration of halooxoacid ions lower than 0.01 mol/l, as described above, abnormal etching easily occurs in which a portion of the semiconductor layer below the opening can be excessively etched. Within the range of low concentrations of halooxoacid ions, as described above, the ratio of the direct reaction between a metal, such as Al, and hydrofluoric acid to the reaction including oxidation of Al and dissolution of the produced oxide with hydrofluoric acid is increased. Therefore, it is preferable that the concentration of halooxoacid ions is at least 0.02 mol/l, more preferably 0.04 mol/l, to produce uniform etching.
The use of an etching solution having the above composition facilitates batch formation of a multi-layer laminated structure comprising a metal layer, an ohmic contact layer and a semiconductor layer, because the same etching solution is used for etching both the metal layer and the ohmic contact layer, and can completely prevent the generation of a gap between the conductor layer and the ohmic contact layer. It is thus possible to stably manufacture an electronic device exhibiting excellent characteristics and high reliability. The addition of iodine ions and/or a water-soluble organic solvent to the etching solution prevents etching defects caused by halogen precipitation, and further improves the uniformity of etching process.
Examples of materials used for the conductor layer to which the prevent invention can be usefully applied include Al, Mo, Ni, Ta, Pt, Ti, Pd, W, Co, Cr and the like, alloys thereof, and metallic compounds (silicide, etc.) comprising these metals and semiconductors. The conductor layer can include a multi-layer structure comprising at least two layers of a metal, an alloy or a metallic compound.
Examples of semiconductors which can be used in the present invention include Si, Ge, GaAs, GaSb, InAs, InSb and the like. The semiconductor in any one of amorphous, polycrystal and single crystal forms can be used.
In the description of the present invention, the statement that the width of the opening of the conductor layer is greater than that of the ohmic contact layer is intended to mean that a minimum width of the opening of the conductor layer (which is wider at an upper surface than along a depthwise direction thereof) is greater than the maximum width of the opening of the ohmic contact layer (which similarly changes in the depthwise direction thereof).
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1(a) and 1(b) are graphs showing the relations between the etching rates of Al and Si and the etching agent composition according to a first embodiment of the present invention;
FIGS. 2(a) and 2(b) are graphs showing the relation between the average surface roughness Ra of Al and the etching agent composition;
FIG. 3 is a graph showing the relations between the acetic acid concentration and the etching depth and variations in etching depth in a substrate;
FIGS. 4(a), 4(b) and 4(c) are schematic sectional views showing the etching state of a multi-layer structure comprising a metal and a semiconductor;
FIGS. 5(a) through 5(e) are a schematic sectional views showing the process of manufacturing a thin film transistor substrate for a liquid crystal display according to a second embodiment of the present invention;
FIG. 6 is a graph showing the Id-Vg characteristics of a thin film transistor;
FIGS. 7(a) through 7(e) are schematic sectional views showing the process of manufacturing a TFT substrate according to a third embodiment of the present invention;
FIG. 8 is a sketch showing a sectional SEM image of a channel portion;
FIGS. 9(a) through 9(e) are schematic sectional views showing the process of manufacturing a liquid crystal display TFT substrate according to a fourth embodiment of the present invention;
FIG. 10 is a sketch showing a sectional SEM image of a section of a channel portion;
FIG. 11(a) and 11(b) through 11(d) are plan and sectional views, respectively, showing a portion of a TFT substrate according to a fifth embodiment of the present invention;
FIG. 12 is a schematic plan view showing the TFT substrate according to the fifth embodiment;
FIGS. 13(a) and 13(b) are plan and sectional views, respectively, showing the process of manufacturing the TFT substrate according to the fifth embodiment;
FIGS. 14(a) and 14(b) are plan and sectional views, respectively, showing the process of manufacturing the TFT substrate of according to the fifth embodiment;
FIGS. 15(a) and 15(b) are plan and sectional views, respectively, showing the process of manufacturing the TFT substrate according to the fifth embodiment;
FIG. 16 is a sectional view showing a conventional TFT;
FIGS. 17(a) and 17(b) are sketches showing a sectional SEM image of a channel portion of a conventional TFT;
FIG. 18 is a graph showing the relations between the methanol concentration and the etching depth and variations in etching depth within a substrate; and
FIG. 19 is a graph showing the relations between the ethanol concentration and the etching depth and variations in etching depth within a substrate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in detail with respect to the following embodiments. It is understood that the present invention is not limited by these embodiments.
(Embodiment 1)
According to the first embodiment of the present invention, Al or i-type amorphous silicon (a-Si) was deposited on a glass substrate by a sputtering or plasma CVD process, and the relations between the etching solution composition and the etching rate and the surface conditions were examined. The results obtained are shown in FIGS. 1 to 4 and Table 1.
FIGS. 1(a) and 1(b) are graphs showing the relations between the etching rates of Al and i-type a-Si and the HF and HIO 3 concentrations of an etching solution. As shown in FIG. 1(a), the etching rate of Al tends to increase with increases in the HF concentration, and first increase and then decrease with increases in HIO 3 concentration. FIG. 1(b) shows that the etching rate of Si increases with increases in the HF concentration and HIO 3 concentration, but is saturated at a HIO 3 concentration of 0.04 mol/l.
FIGS. 2(a) and 2(b) show the average surface roughness Ra as functions of HF and HIO 3 concentrations when Al was etched to a depth of 200 nm. FIG. 2(a) reveals that the average surface roughness decreases with increases in the HIO 3 concentration to become substantially equal to the average surface roughness (0.8 to 1.5 nm) of a substrate at 0.04 mol/l. FIG. 2(b) reveals that the average surface roughness of Al is substantially equal to the average surface roughness of the substrate up to a HF concentration of 0.33 mol/l, and then increases to 10 nm or more at a HF concentration of over 0.5 mol/l.
FIG. 3 is a graph showing the changes in variations of the etching depth within a glass substrate, having Al deposited thereon by sputtering, which were caused by the addition of acetic acid. In FIG. 3, each data point along a solid line represents the average etching depth based on measurements at five points within the substrate, and each data point along a broken line represents the variation thereof in each of static etching and rocking etching. The variation is obtained by dividing a greater difference between the average and the maximum or minimum of the etching depth by the average. As shown in FIG. 3, the addition of acetic acid inhibits distribution of the etching depth within the substrate. FIG. 18 and 19 show the result of measurements taken when methanol and ethanol were respectively added in place of acetic acid. Similar to the use of acedic acid, the addition of methanol or ethanol inhibits distribution of the etching depth within the substrate.
Table 1 shows the results of visual observation of the Al surface state during etching and after etching. This table shows that the addition of ethanol can inhibit precipitation of a black substance, i.e., iodine.
TABLE 1______________________________________Solution CompositionHF HIO.sub.3 Ethanol(mol/l) (mol/l) (vol %) Surface State______________________________________0.1 0.06 0 Slight precipitation of black substance on the surface.0.1 0.06 10 No precipitation.0.1 0.06 20 No precipitation.0.1 0.06 30 No precipitation.0.1 0.12 0 Precipitation of black substance on the surface.0.1 0.12 10 Slight precipitation of black substance on the surface.0.1 0.12 20 No precipitation.0.1 0.12 30 No precipitation.______________________________________
An a-Si layer of 100 nm and an n + -type a-Si layer of 20 nm were then deposited by the plasma CVD method on the glass substrate (100 mm×100 mm) having a SiN x film formed thereon, and Al was subsequently deposited to 300 nm by sputtering.
After a resist (produced by Tokyo Oka Co., OFPR800Y-4) pattern was used to form twelve concave and twelve convex patterns measuring 2 to 20-μm square, the substrate was immersed in etching solutions having various compositions for examining changes in the etching state with time. The results showed no etching defect, such as separation of the resist from the substrate, in both the concave and convex patterns.
FIGS. 4(a), 4(b) and 4(c) are representative views showing sections of the concave patterns, as observed using a scanning electron microscope (SEM). It was found that, by using etching agents within the composition range of the present invention, etching proceeds in all patterns, as shown in FIGS. 4(a) and 4(b), and the depth of etching can be controlled by the immersion time. It was also found that for example, in patterns of 5 μm square, variations in the shapes of the patterns formed are within ±0.1 μm--this indicates that extremely uniform etching can be performed using the etching agents according to the present invention.
It was further found that if the HIO 3 concentration is 0.008 mol/l (lower than 0.01 mol/l), abnormal etching occurs in the peripheral portion of the a-Si layer, as shown in FIG. 4(c), and only a small on-current can be obtained for an electronic device.
(Embodiment 2)
A thin film transistor substrate for driving a liquid crystal display having 720×480 pixels was formed using the electronic device manufacturing method of the present invention, as shown in FIGS. 5(a) through 5(e).
Referring to FIG. 5(a), after a glass substrate 500 (Corning 7059) measuring 100×100 mm was precisely cleaned, a pattern of a transparent electrode 501 (ITO) as formed. A Cr film was then formed to 100 nm by sputtering, and patterned using an etching solution ((NH 4 ) 2 Ce(NO 3 ) 6 !: NHO 3 : H 2 O=500 g: 1900 cc: 1870 cc) to form gate electrodes 503 and gate wiring 502.
Referring to FIG. 5(b), SiN x 504, i-type a-Si 505 and n + -type a-Si 506 were then deposited to a thicknesses of 300 nm, 100 nm and 20 nm, respectively, by plasma CVD.
Referring to FIG. 5(c), the n + -type a-Si layer and i-type a-Si layer were then separated into respective pixels using an etching solution (HF: 0.54 mol/l, HIO3: 0.04 mol/l, NH 4 I: 0.005 mol/l).
Referring to FIG. 5(d), after contact holes for the pixel electrodes and the gate wiring were formed, a W layer 507 and an Al layer 508 were deposited to 50 nm and 250 nm, respectively, by sputtering.
Referring to FIG. 5(e), in order to form source-drain electrodes and wiring and channel portions, the substrate was then immersed in an etching solution containing 0.1 mol/l of HF and 0.04 mol/l of HIO 3 for 7 minutes to continuously etch the Al layer 508, the W layer 507 and the n + -type a-Si.
In the final stage, a passivation layer comprising SiN x was deposited to 400 nm by the plasma CVD method, contact holes were formed on the gate wiring, and the source-drain wiring was formed to complete the thin film transistor.
Measurements of the Id-Vg characteristics of the thus-formed thin film transistor are shown in FIG. 6. As is obvious from FIG. 6, good results were obtained, i.e., the on-current I ON was 1.8 to 30 μA, and the off-current I OFF was several pA.
Although the above embodiments relate to etching for forming the channel portions, and the source-drain electrodes, for separating respective pixels and so on in the thin film transistor, etching can of course be used for other stages, for example, for forming the gate electrodes and wiring. Needless to say, the present invention can also be applied to a MOS polysilicon gate, CCD, an image scanner and various multi-layer structures, each comprising a conductor layer and a semiconductor layer in various electronic devices other than the thin film transistor.
(Embodiment 3)
An array of 100×100 TFTs were formed using the electronic device manufacturing method of the present invention in accordance with the procedure shown in FIGS. 7(a) through 7(e).
Referring to FIG. 7(a), after a glass substrate 700 (Corning 7059) measuring 100×100 mm was precisely cleaned, a Cr film 100 nm thick was formed by sputtering, and then patterned using an etching solution (ammonium cerium (IV) nitrate: 71% HNO 3 : H 2 O=500 g : 1900 cc: 1870 cc) to form gate electrodes 701, having a width of 7 μm, and gate wiring 702, having a width of 5 μm.
Referring to FIG. 7(b), a SiN x layer 703, an i-type a-Si layer 704 and an n + -type a-Si layer 705 were then deposited to 300 nm, 100 nm and 20 nm, respectively, by plasma CVD. The film formation conditions for each of the films are shown in Table 2.
TABLE 2______________________________________ SiN.sub.2 i-type a-Si n.sup.+ -type a-Si______________________________________Gas flowrate(sccm)SiH.sub.4 30 200 200H.sub.2 1000 800 800NH.sub.3 60 -- --PH.sub.3 -- -- 2Pressure 0.8 0.8 0.8(Torr)RF power (W) 400 100 100Film 300 250 250formationtemperature(°C.)______________________________________
Referring to FIG. 7(c), an n + -type a-Si layer and an i-type a-Si layer were separated to form respective TFT devices using an etching solution (HF: 0.54 mol/l, HIO 3 : 0.04 mol/l).
Referring to FIG. 7(d), after contact holes for the gate wiring were formed, an Al layer 706 (containing 1% Si) was deposited to a thickness of 250 nm by sputtering.
Referring to FIG. 7(e), in order to form source-drain electrodes and wiring and channel portions 707 (channel length 4 μm, channel width 6 μm), the Al layer and the n + -type a-Si layer were simultaneously etched by immersing the substrate in an etching solution (25° C.) containing 0.1 mol/l of HF and 0.04 mol/l of HIO 3 for 3 minutes.
FIG. 8 is a sketch showing an enlarged sectional SEM image of a channel portion after etching. It is found from FIG. 8 that a smooth opening is formed without a gap between the Al layer and the n + -type a-Si layer.
After the resist was removed, a passivation layer comprising SiN x was deposited to a thickness of 400 nm, and contact holes were formed on the gate wiring and source-drain wiring to complete the thin film transistors.
The carrier mobility, threshold values, ON currents and OFF currents of the thus-manufactured 10 4 TFTs were measured, and variations thereof were evaluated. A reliability test was also carried out, and characteristics of the device following the test were compared with the initial values. The results obtained are shown in Table 3. In the reliability test, the TFT substrate was placed in an environmental tester at a temperature of 85° C. and a relative humidity of 85% and allowed to stand for 1000 hours.
(COMPARATIVE EXAMPLE 1)
For comparison, thin film transistors were manufactured by the same method as Embodiment 3 with the exception that Al and n + -type a-Si were respectively etched using the etching solutions described below. In a channel portion, a gap was observed between the Al layer and n + -type a-Si layer, as shown in FIG. 17(a).
Etching solution for Al;
85% phosphoric acid: 71% nitric acid:
glacial acetic acid: water =16:1:2:1 (40° C.)
Etching solution for n + -type a-Si;
49% hydrofluoric acid: 71% nitric acid:
glacial acetic acid =1:60:120 (15.2° C.)
The thus-obtained sample was evaluated by the same method as Embodiment 3. The results obtained are shown in Table 3.
TABLE 3______________________________________ ComparativeEmbodiment 3 Example 1Initial After test Initial After test______________________________________Carrier 0.8 ± 0.1 0.78 ± 0.15 0.7 ± 0.15 0.4 ± 0.2mobility(cm2/v sec)Threshold 1.0 1.0 1.5 2.5(V)ON current 2 × 10.sup.-16 2 × 10.sup.-6 1.5 × 10.sup.-6 2 × 10.sup.-6(A)OFF current 1 × 10.sup.-13 1 × 10.sup.-12 1 × 10.sup.-12 1 × 10.sup.-9(A)______________________________________
As shown in Table 3, the TFTs of this embodiment have excellent carrier mobility and TFT characteristics and exhibit less variation than the comparative example 1. Therefore devices produced using the method according to the present invention exhibited superior characteristics, as compared with devices produced using the conventional method. It was also found that the devices produced according to the present invention show substantially no deterioration in characteristics under severe environmental conditions and have high reliability.
(Embodiment 4)
A thin film transistor substrate for driving a liquid crystal display having 710×480 pixels was manufactured using the electronic device manufacturing method of the present invention, as shown in FIGS. 9(a) through 9(e).
Referring to FIG. 9(a), after a glass substrate 900 (Corning 7059) measuring 100×100 mm was precisely cleaned, a pattern of a transparent electrode 908 (ITO) was formed. Gate electrodes 901, having a width of 7 μm, and gate wiring 902 were subsequently formed by the same method as described in Embodiment 3 (above).
Referring to FIG. 9(b), a SiN x layer 903, an i-type a-Si layer 904 and an n + -type a-Si layer 905 were then deposited to thicknesses of 300 nm, 100 nm and 20 nm, respectively, by the plasma CVD process under the conditions shown in Table 2.
Referring to FIG. 9(c), the n + -type a-Si layer 905 and the i-type a-Si layer 904 were then separated to form respective pixels using an etching solution (HF: 0.54 mol/l, HIO 3 : 0.04 mol/l).
Referring to FIG. 9(d), after contact holes for the pixel electrodes and gate wiring were formed, a W layer 909 and an Al layer 906 were deposited to 50 nm and 250 nm, respectively, by sputtering.
Referring to FIG. 9(e), in order to form source-drain electrodes and wiring and channel portions (channel length 4 μm, channel width 6 μm), the Al, W and n + -type a-Si layers were continuously etched by immersing the substrate in an etching solution containing 0.1 mol/l of HF and 0.04 mol/l of HIO 3 for 7 minutes.
FIG. 10 is a sketch showing an enlarged sectional SEM image of the channel portion 907 after etching the n + -type a-Si. Referring briefly to FIG. 17(b), it is recalled that in the conventional process, a gap 1702 was formed between the W layer and n + -type a-Si layer. Referring back to FIG. 10, it is shown that, in accordance with the present invention, a gap is not formed between the Al layer and the W layer, and an smooth opening was obtained.
In the final stage, a passivation layer comprising SiN x was deposited to a thickness of 400 nm by plasma CVD, and contact holes were formed on the gate wiring and source-drain wiring to complete a thin film transistor substrate.
Evaluation of the thin film transistors of Embodiment 4, using the same methods as in Embodiment 3, showed that the thin film transistors exhibited excellent characteristics without variations, as in Embodiment 3. The reliability was also excellent as in Embodiment 3.
A liquid crystal display was assembled using a TFT substrate, which was manufactured separately, and an image was evaluated by inputting video signals to the display. The image was found to have excellent contrast and was displayed stably.
(Embodiment 5)
In this embodiment, the TFT substrate shown in FIGS. 11 through 15 was manufactured.
In order to prevent breakage of transistors due to static electricity generated in the manufacturing process, a guard ring 1128 connecting source terminals 1119 and gate terminals 1118 is provided, as shown in FIGS. 15(a) and 15(b). The guard ring 1128 is removed in the final stage.
The structure of a TFT substrate will now be described.
FIGS. 11(a) through 11(d) illustrate the TFT substrate of this embodiment, wherein FIG. 11(a) is a plan view and FIGS. 11(b), 11(c) and 11(d) are sectional views taken long lines A--A, B--B and C--C, respectively, in FIG. 11(a).
The TFT has a reverse stagger structure including a Cr gate electrode 1112 having a width of 10 μm and a thickness of 100 nm, and Cr gate wiring 1121 for supplying scanning signals to the gate electrode 1112, both of which are formed on a glass substrate 1111 (Corning Co. 7059). A gate insulating film 1113 comprising a silicon nitride thin film having a thickness of 200 nm was formed on the gate electrode 1112 and gate wiring 1121. A semiconductor active film 1114 having a thickness of 50 nm and comprising i-type a-Si was formed on the gate insulating film 1113, and an Al source electrode 1116 and drain electrode 1117 having a thickness of 100 nm and a width of 10 μm were further formed on the semiconductor layer 1114. An n + -type a-Si ohmic contact layer 1115 having a thickness of 20 nm and containing phosphorus is formed between the semiconductor active layer 1114 and the source and drain electrodes 1116 and 1117.
Many thus-formed TFTs are formed in a matrix at a pitch of 100 μm on the substrate, as shown in FIG. 12. On the peripheral portions of the substrate 1111 are formed source terminals 1119 for supplying image signals, provided from an external image circuit, to the source electrodes 1116 through the source wirings 1122, and gate terminals 1118 for supplying scanning signals, provided from an external scanning circuit, to the gate electrodes 1112 through the gate wirings 1121. The source terminals 1119 are formed using Al, which is the same conductor material used for the source electrodes 1116 and the source wiring 1122. The gate terminals 1118 also Al, and are respectively formed on the gate insulating films 1113 through the contact holes 1123 formed in the gate insulating films 1113 on the gate wirings 1121.
Referring back to FIGS. 11(b) through 11(d), a protective film 1127, comprising a silicon nitride film and having a thickness of 300 nm, is formed on the TFTs 1101, gate wirings 1121, source wiring 1122, source terminals 1119 and gate terminals 1118. However, the surfaces of the source terminals 1119 and gate terminals 1118 are partially exposed so that they can be electrically connected to the image circuit and the scanning circuit. Both widths S1 and G1 of the conductors which respectively form the source terminals 1119 and gate terminals 1118 are 50 μm, and both effective connection widths S0 and G0 of the source terminals 1119 and gate terminals 1118, from which the protective film 1127 is removed, are 42 μm. Namely, the processing precision is 4 μm.
The method of manufacturing the TFT substrate of this embodiment is described below.
A Cr thin film having a thickness of 100 nm was formed by sputtering on the surface of a glass substrate 1111, upon which a pixel electrode 1120 comprising a transparent conductive film was formed. A resist was formed on the surface of the glass substrate and then subjected to mask exposure, development, etching and separation treatment to form gate electrodes 1112 and gate wiring 1121 in a desired shape. This is shown in FIGS. 13(a) and 13(b). FIG. 13(a) is a schematic plan view, FIG. 13(b) is a sectional view taken along line A--A of FIG. 13(a).
A gate insulating film 1113 having a thickness of 200 nm and comprising a SiN x thin film, an i-type a-Si film 1114 having a thickness of 50 nm, and an n + -type a-Si ohmic contact layer 1115 having a thickness of 20 nm and containing phosphorus were then formed, by the plasma CVD process, on the surface of the substrate 1111 on which the gate electrodes 1112 and gate wiring 1121 were formed.
The semiconductor active layer 1114 and the ohmic contact layer 1115 were subjected to a photo phosphorus process to form semiconductor islands having a predetermined shape. Contact holes 1123 were formed in the gate insulating film 1113 on the pixel electrode 1120 and gate wiring 1121. This state is shown in FIG., 14. FIG. 14(a) is a schematic plan view, and FIG. 14(b) is a sectional view taken along line A--A in FIG. 14(a).
An Al thin film having a thickness of 100 nm was formed on the substrate including the ohmic contact layer 1115 by the sputtering method using an Al target containing 1% Si. A resist film 1124 was formed on the surface of the Al thin film, exposed and developed, and the Al and ohmic contact layer were then etched by the same method as Embodiment 1 to form the source electrodes 1116, source wiring 1122, source terminals 1119, drain electrodes 1117 and guard ring 1128 for electrically connecting the source terminals 1119 and gate terminals 1118, gate terminals 1118 and channels 1126, as shown in FIGS. 15(a) and 15(b). At this time, the gate terminals 1118 were formed by processing the conductor so as to completely cover the gate wiring 1121 below the contact holes 1123 with Al wiring. FIG. 15(a) is a schematic plan view, and FIG. 15(b) is a sectional view taken along line A--A in FIG. 15(a).
In this embodiment, as shown in FIGS. 15(a) and 15(b), the ohmic contact layer 1115 is electrically connected to the source wiring 1122, source terminals 1119, guard ring 1128, gate 1121 and s 1118, gate wiring 1121 and gate electrodes 1112 through the source electrodes 1118 located immediately above the ohmic contact layer. However, since all surfaces of the gate terminals 1118, gate wiring 1121 and gate electrodes 1112 are covered with the gate insulating film 1113 serving as an insulator or the conductor which forms the source wiring 1122, and all conductors which form the source wiring 1122, source terminals and guard ring 1128 are covered with the resist film 1124 serving as an insulator. Namely, all conductive members electrically connected to the ohmic contact layer 1115 are covered with an insulator. When the ohmic contact layer 1115 is treated with an etching solution containing an electrolyte, therefore, the ohmic contact layer 1115 does not form a battery with another conductor, and is not abnormally etched due to the battery effect. In etching of the ohmic contact layer 1115, it is possible to prevent side etching due to the battery effect by covering the layers electrically connected to the ohmic contact layer.
Referring again to FIGS. 11(b) through 11(d), a protective film 1127 comprising a silicon nitride thin film was then formed, and a resist film was formed on the surface thereof and then subjected to mask exposure, development, etching and separation treatment to expose the source terminals 1119 and gate terminals 1118. Since the gate terminals 1118 and source terminals 1119 were formed on the gate insulating film 1113, the gate terminals could be formed only by removing the protective film 1127. The guard ring 1128 for connecting the gate wiring 1121 and source wiring 1122 was then removed to form the TFT substrate shown in FIG. 11(a).
The thus-formed TFT substrate 1111 includes a plurality of TFTs arranged in a matrix with a pitch of 100 μm. Along a periphery of the substrate 1111 are arranged the source terminals for receiving the video signals transmitted from an external video circuit to the source electrodes 1116 through the source wiring 1122, and the gate terminals 1118 for receiving scanning signals supplied from an external scanning circuit to the gate electrodes 1112 through the gate wiring 1121.
The etching agent of the present invention enables fine patterning of a multi-layer structure comprising a conductor and a semiconductor with a single etching agent. Since this patterning has high uniformity, it can preferably be applied to manufacture of electronic devices having a large area and high density.
The electronic device of the present invention exhibits excellent characteristics, less variations, and high reliability. The present invention can provide many elements such as TFTs which are required to operate at high speeds and have uniform characteristics.
The electronic device manufacturing method of the present invention provides a simple manufacturing process with high yield, as compared with conventional methods. It is thus possible to decrease the production costs of various electronic devices using the above-described methods pertaining to the present invention. | An etching agent and an electronic device manufacturing method using the etching agent. The etching agent contains, in a solution, hydrofluoric acid at a concentration of 0.05 to 0.5 mol/l, and halooxoacid ions, represented by the formula (XO n ) p- (wherein X is a halogen element, n is 3, 4 or 6, p is 1, 2 or 3), at a concentration of at least 0.01 mol/l. An electronic device manufactured using the etching agent requires only a single etching step to etch both conductive layers (such as aluminum) as well as ohmic contact layers (a-Si). | Concisely explain the essential features and purpose of the invention. | [
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present invention relates to an etching agent, an electronic device and a method of manufacturing an electronic device.",
"More particularly, the present invention relates to an etching agent, and a method of manufacturing an electronic device using the etching agent, which permits batch etching of a multi-layer film comprising a conductor layer and a semiconductor layer using the same etching agent.",
"The present invention further relates to an electronic device and a method of manufacturing the device in which the shapes of openings etched in a conductor layer and an ohmic contact layer are controlled so as to improve the characteristics and reliability of the electronic device.",
"Description of the Related Art Conventional etching processes used in the production of semiconductor materials such as silicon typically employs a mixed solution of hydrofluoric acid, nitric acid and acetic acid.",
"However, because this etching solution violently generates heat and nitrogen oxide gas, and causes degradation or separation of resist due to the nitric acid during the etching process, the formation of a precise (fine) pattern is considered difficult.",
"In order to solve the above problem, the inventors of the present invention developed an etching agent containing hydrofluoric acid and an oxoacid or an oxoacid salt compound (Japanese Patent Application No. 4-285338).",
"On the other hand, for example, in the production of an electronic device used for driving a liquid crystal display, a manufacturing method resulting in higher pattern precision and device productivity (yield) is demanded with increases in the display size and pixel density.",
"The method of manufacturing an electronic device is described below with reference to the reverse stagger structure thin film transistor (TFT) shown in FIG. 16, as an example.",
"A conventional TFT is manufactured, for example, by the following method.",
"A Cr film is first formed on a glass substrate 1600 by sputtering, and gate electrodes 1601 and gate wiring 1602 are then formed by patterning.",
"A gate insulating film 1603 (e.g., SiNx), an i-type (un-doped) amorphous silicon (a-Si) layer 1604 and an n + -type (doped) a-Si layer 1605 are then deposited by a plasma CVD process, or a similar process.",
"The n + -type a-Si layer and i-type a-Si layer are etched using a HF-HNO 3 mixture to separate respective devices, and a conductor layer Al (containing 1 to 2% Si) is then formed by sputtering.",
"A source-drain electrode, wiring 1606, and a channel portion 1607 are then formed by etching the conductor layer Al with a phosphoric acid etching solution, and n + -type a-Si is etched with a mixture of HF and HNO 3 .",
"Finally, a passivation film is deposited using the plasma CVD process, and openings are formed for the gate wiring and source-drain wiring to complete the manufacture of the thin film transistor.",
"When a TFT is formed by the above method, separate steps of etching the conductor layer 1606 and etching the ohmic contact semiconductor layer 1605 are required.",
"In the conventional method, after a resist pattern is formed, the conductor layer 1606 is etched with a first etching solution specifically formulated for a metal layer, and the ohmic contact layer 1605 is then etched with a second etching solution comprising HF and HNO 3 which is specifically formulated for the ohmic contact layer.",
"Since the conventional method uses two types of etching solutions, and washing is required between the respective etching steps, the etching process is very time consuming and thus reduces productivity.",
"In addition, the repetition of the etching and washing steps deteriorates the adhesion of the resist deposited on the device during production, thereby easily producing defects in the resultant pattern.",
"Moreover, when an etching barrier layer is provided between the conductor layer and the ohmic contact layer of a TFT, the use of multiple etching solutions and multiple etching a washing steps becomes an additional problem.",
"Further, the etching of aluminum (Al), which is a material typically used to form conductor layers, creates an additional problem because the typical Al etching solution has a high viscosity because etching remainder (un-etched Al) causes short-circuit defects, particularly in fine pattern portions of a resulting electronic device.",
"The conventional method shown in FIG. 16 also causes side etching of the ohmic contact layer, and thus forms a gap 1701 due to etching of the ohmic contact layer below the exposed edge of the conductor layer, as shown in FIG. 17(a).",
"The TFT frequently comprises a conductor layer formed on top of a barrier layer (for example, tungsten (W)) whose purpose is to prevent the diffusion of Al.",
"When a barrier layer is used, a gap 1702 is typically produced between the W layer and an exposed edge of the n + -type a-Si ohmic contact layer, as shown in FIG. 17(b).",
"Although it is commonly known that the gaps 1701 and 1702 are produced during etching of a multi-layer film, substantially no attention has been paid to the effect of these gaps on the characteristics of a device.",
"However, during the development of an electronic device having high density and excellent characteristics, the inventors of the present invention found that the degree of precision produced by the conventional manufacturing method is limited, and that the cause of this limit is related to the above-mentioned gaps.",
"Namely, there are definite relationship between the gaps and the characteristics of a TFT device, variations in the characteristics between various TFT devices, and the reliability of the TFT devices.",
"That is, the formation of a small gap deteriorates the characteristics of a device, increases variation in characteristics and deteriorates the reliability of the device.",
"SUMMARY OF THE INVENTION An object of the present invention is to provide an etching agent which enables the continuous formation of a fine pattern in a multi-layer structure including a conductor layer, a semiconductor layer, etc.",
"by using a single etching solution.",
"Another object of the present invention is to provide an electronic device having excellent characteristics, fewer performance variations and excellent reliability.",
"A further object of the present invention is to provide an electronic device manufacturing method in which electronic devices can be generated using a short manufacturing process which produces a high yield.",
"In accordance with a first aspect of the present invention, an etching agent contains, in a solution, 0.05 to 0.5 mol/l of hydrofluoric acid and at least 0.01 mol/l of halooxoacid ions represented by the formula (XO n ) p - wherein X is a halogen element, n is 3, 4 or 6, and p is 1, 2 or 3.",
"In accordance with a second aspect of the present invention, an etching agent contains, in a solution, hydrofluoric acid, halooxoacid ions represented by the formula XO n ) p- wherein X is a halogen element, n is 3, 4 or 6, and p is 1, 2 or 3, and a halogen precipitation inhibitor.",
"In accordance with a third aspect of the present invention, an electronic device comprises a multi-layer film having a semiconductor layer, an ohmic contact layer and a conductor layer, wherein openings are respectively formed in portions of the ohmic contact layer and the conductor layer, and a passivation film is formed within a predetermined region including the openings, a width of an opening formed in the conductive layer being larger than a width of an adjoining opening formed in the ohmic contact layer.",
"In accordance with a fourth aspect of the present invention, an electronic device manufacturing method comprises successively laminating a semiconductor layer, an ohmic contact layer and a conductor layer to form a multi-layer film, forming openings by continuously removing portions of the conductor layer and the ohmic contact layer using an etching solution which etches both the conductor layer and the ohmic contact layer during a single etching step, wherein the etching solution etches the conductor layer at a higher etching rate than the ohmic contact layer, and then forming a passivation film in a predetermined region including the openings.",
"In accordance with a fifth aspect of the present invention, an electronic device manufacturing method comprises continuously etching an ohmic contact layer and a conductor layer, which are laminated on the surface of a semiconductor layer, using an etching agent containing, in a solution, 0.05 to 0.5 mol/l of hydrofluoric acid and at least 0.01 mol/l of halooxoacid ion represented by the formula (XO n ) p- wherein X is a halogen element, n is 3, 4 or 6, and p is 1, 2 or 3.",
"During experimentation to determine new manufacturing processes for increasing the efficiency and yield of electronic devices, and for shortening the manufacturing process, the inventors found that an etching solution containing hydrofluoric acid and halooxoacid ions at appropriate concentrations is capable of etching semiconductors, various metals, alloys and metallic compounds such as silicides and the like to form a fine pattern.",
"The inventors believe one possible mechanism of the etching process is that the halooxoacid ions, serving as a strong oxidizing agent, oxidize a solid surface of a semiconductor, a metal or the like, and then the hydrofluoric acid dissolves the thus-produced oxide.",
"For a metal such as aluminum (Al) or the like which reacts with hydrofluoric acid, therefore, when the above-mentioned etching solution is used, oxidation with halooxoacid ions preferentially proceeds, and the generation of gas due to direct reaction between a metal and hydrofluoric acid is thus inhibited, thereby permitting stable etching.",
"In other words, the use of the etching agent of the present invention prevents the violent generation of heat and gases in reaction with a semiconductor, a metal or a metallic compound, and thus enables the formation of a fine pattern in a semiconductor, metal or the like.",
"Also, because resist reacts very stably to the etching agent, side etching of the resist, which can result in a deterioration in the adhesion of the resist or separation thereof, is inhibited, thereby permitting the formation of a fine pattern.",
"Further, since the etching agent of the present invention is chemically stable, the etching agent is capable of stable etching for a long period of time and therefore provides a cost advantage, as compared with conventional etching agents.",
"It is thus possible to stably form a fine pattern in a multi-layer laminated structure comprising a metal layer, a metallic compound layer and a semiconductor layer by using the same etching agent.",
"The metal layer and semiconductor layer may have a multi-layer structure comprising at least two layers, so long as the etching agent of the present invention can be applied.",
"The etching agent of the present invention preferably contains 0.05 to 0.5 mol/l of hydrofluoric acid and 0.01 mol/l of halooxoacid ions.",
"If the concentration of hydrofluoric acid exceeds 0.5 mol/l, variations in the etching process occur easily due to the direct reaction between a metal and hydrofluoric acid.",
"Because these variations affect the semiconductor layer which serves as a ground layer, and adversely affect the characteristics of a device, the concentration of hydrofluoric acid is preferably less than 0.5 mol/l.",
"This is because, while etching an amorphous thin film transistor having an ohmic contact layer which is several tens of nm thick and a conductor layer which is several hundred nm thick, both of which being formed on an i-type Si layer, if the concentration of hydrofluoric acid over 0.5 mol/l, then the etching rate is significantly decreased in the direction of depth, thereby causing difficulties in reliably obtaining a desired end point.",
"The concentration range of hydrofluoric acid depends upon the concentration of oxoacid ions, but it is more preferably 0.33 mol/l or less.",
"Within this range, the generation of bubbles due to the direct reaction between hydrofluoric acid and a metal is further inhibited, and more uniform etching thus becomes possible.",
"On the other hand, a concentration lower than 0.05 mol/l significantly decreases the etching rates of the semiconductor layer and the conductor layer, and is this undesirable for practical use.",
"The etching agent of the present invention preferably contains halooxoacid ions at a concentration of 0.01 mol/l or more, more preferably 0.02 mol/l or more, and most preferably 0.04 mol/l or more.",
"This is because, at a concentration lower than 0.01 mol/l, although reasons are not well understood, abnormal etching easily occurs in which a portion around the etched portion of the semiconductor layer is extremely etched.",
"Within the region of low concentrations of halooxoacid ions, the ratio of the direct reaction between a metal such as Al or the like and hydrofluoric acid to the reaction including oxidation of Al with halooxoacid ions and dissolution of the produced oxide with hydrofluoric acid is increased, as described above.",
"It is thus preferable for uniform etching that the concentration of halooxoacid ions is 0.02 mol/l or more, and more preferably 0.04 mol/l or more.",
"At a high concentration of halooxoacid ions, the etching rate is decreased, and halogen material such as iodine (I) or the like is precipitated due to the etching reaction.",
"Therefore, the upper limit of the concentration of halooxoacid ions is appropriately determined in accordance with a design of an etched device (the thicknesses of the semiconductor layer and the conductor layer, etc.) or in consideration of a balance with iodine ions for preventing precipitation of halogen material or the concentration of an organic solvent.",
"The halooxoacid ions used in the present invention can be obtained by dissolving halooxoacid or halooxoacid salt in water.",
"Examples of halooxoacids or halooxoacid salt compounds include bromic acid (HBrO 3 ), potassium bromate (KBrO 3 ), sodium bromate (NaBrO 3 ), ammonium bromate (NH 4 BrO 3 ), calcium bromate (Ca(BrO 3 ) 2 ), magnesium bromate (Mg(Bro 3 ) 2 ), aluminum bromate (Al(BrO 3 ) 3 ), perbromic acid (HBrO 4 ), lithium perbromate (LiBrO 4 ), potassium perbromate (KBrO 4 ), iodic acid (HIO 3 ), potassium iodate (KIO 3 ), sodium iodate (NaIO 3 ), ammonium iodate (NH 4 IO 3 ), calcium iodate (Ca(IO 3 ) 2 ), magnesium iodate (Mg(IO 3 ) 2 ), aluminum iodate (Al(IO 3 ) 3 ), periodic acid (HIO 4 ), lithium periodate (LiIO 4 ), potassium periodate (KIO 4 ) and the like.",
"Of these compounds, iodic acid (HIO 3 ), potassium iodate (KIO 3 ) and potassium bromate (KBrO 3 ) are easiest to handle and are thus preferable.",
"Because iodic acid (HIO 3 ) does not contain a metal element which could possibly act as a contamination source for a semiconductor material, it is believed to be optimal for use in an etching agent for a semiconductor device which is a representative electronic device.",
"The etching agent of the present invention preferably contains iodine ions.",
"The addition of iodine ions changes iodine (I 2 ) generated by etching into I 3 - which dissolves the agent, thereby preventing the precipitation of halogen.",
"NH 4 I, KI, NaI or the like is preferably used as an iodine ion source.",
"It is thus possible to prevent etching defects in the precipitation portion and perform a uniform and stable etching process.",
"The etching agent of the present invention also preferably contains a water-soluble organic solvent such as alcohol, carboxylic acid or the like.",
"Examples of alcohols include methanol, ethanol, isopropyl alcohol, propanol, butanol, ethylene glycol, propanediol, butanediol, glycerin and the like.",
"Examples of organic acids include acetic acid, propionic acid and the like.",
"The addition of the organic solvent permits more uniform and stable etching due to the dissolution of the produced halogen such as iodine, and can inhibit variations of the etching depth in a substrate.",
"In the present invention, acetic acid, methanol or ethanol is preferable.",
"However, if the concentration of the organic solvent exceeds by 70% by volume, since the resist is corroded with the organic solvent, the concentration is preferably 70% by volume or less.",
"Even if the etching agent of the present invention has a composition other than the above preferable composition (0.05 to 0.5 mol/l hydrofluoric acid, 0.01 mol/l or more halooxoacid ions), the addition of a halogen precipitation inhibitor can prevent an etching defect in the precipitation portion caused by halogen precipitation, and further improve the uniformity of etching.",
"Iodine ion or a water-soluble organic solvent is preferably used as the halogen precipitation inhibitor.",
"Particularly, NH 4 I, KI, NaI or the like is preferably used as an iodine ion source.",
"As a water-soluble organic solvent, an alcohol such as methanol, ethanol, isopropyl alcohol, propanol, butanol, ethylene glycol, propanediol, butanediol, glycerin or the like, a carboxylic acid such as acetic acid, propionic acid or the like is preferably used.",
"Of these organic solvents, acetic acid, methanol or ethanol are preferred.",
"As described above, the present invention has been achieved based on the findings of the inventors that, during the etching process, the gap formed between the semiconductor layer and the ohmic contact layer significantly affects the characteristics of an electronic device, variations in the characteristics and the reliability of the device.",
"A deterioration in the characteristics and reliability of an electronic device caused by the gap between the conductor layer and the ohmic contact layer are possibly caused by the following phenomenon: If such a gap is formed, a passivation film typically cannot be formed in the gap, and even if the passivation film is formed in the gap, only a rough film with low denseness is formed, and thus the device is liable to deteriorate.",
"Measurement using an energy dispersive X-ray micro-analyzer indicated that the passivation film formed in the gap contained large amounts of impurities such as oxygen, etc.",
"This is possibly due to the position and thinness of the gap, thereby preventing complete removal of the etching solution located in the gap by a cleaning fluid, or preventing the cleaning fluid and etching solution from being completely removed from the gap during a subsequent drying process.",
"The impurities contaminate the channel portion when the passivation film is deposited, and thus deteriorate the device characteristics such as carrier mobility, etc.",
"These impurities can also diffuse into the channel portion over time, after the passivation film is deposited, and thus deteriorate the characteristics of the device.",
"On the other hand, in the electronic device of the present invention, the ohmic contact layer and the conductor layer are continuously etched in a batch manner using an etching solution which causes a higher etching rate of the conductor layer than that of the ohmic contact layer.",
"It is thus possible to make the width of the opening in the conductor layer greater than that of the ohmic contact layer, and thereby to prevent the formation of a gap between both layers.",
"As a result, the entire opening surface can be covered with a dense passivation film, thereby obtaining an electronic device having high reliability.",
"It is also possible to prevent the etching solution or the cleaning fluid from becoming trapped in the gap, and thus inhibits contamination from residual liquids.",
"The resultant electronic device exhibits excellent characteristics such as carrier mobility, etc.",
", and does not exhibit variations thereof, and thus the yield of electronic devices is significantly improved.",
"It is preferable to inhibit the formation of these gaps by using an etching solution containing at least 0.05 to 0.33 mol/l of hydrofluoric acid and 0.1 mol/l or more of halooxoacid ions.",
"The concentration of hydrofluoric acid is more preferably 0.05 to 0.2 mol/l.",
"Within this composition range, the etching rate of the conductor layer is greater than that of the ohmic contact layer, and control over the etching process is improved, thereby providing a reliably reproducible etching process.",
"This also allows for finer (more precise) etching which can be stably performed.",
"The concentration of halooxoacid ions is more preferably at least 0.02 mol/l, most preferably at least 0.04 mol/l.",
"This is because, at a concentration of halooxoacid ions lower than 0.01 mol/l, as described above, abnormal etching easily occurs in which a portion of the semiconductor layer below the opening can be excessively etched.",
"Within the range of low concentrations of halooxoacid ions, as described above, the ratio of the direct reaction between a metal, such as Al, and hydrofluoric acid to the reaction including oxidation of Al and dissolution of the produced oxide with hydrofluoric acid is increased.",
"Therefore, it is preferable that the concentration of halooxoacid ions is at least 0.02 mol/l, more preferably 0.04 mol/l, to produce uniform etching.",
"The use of an etching solution having the above composition facilitates batch formation of a multi-layer laminated structure comprising a metal layer, an ohmic contact layer and a semiconductor layer, because the same etching solution is used for etching both the metal layer and the ohmic contact layer, and can completely prevent the generation of a gap between the conductor layer and the ohmic contact layer.",
"It is thus possible to stably manufacture an electronic device exhibiting excellent characteristics and high reliability.",
"The addition of iodine ions and/or a water-soluble organic solvent to the etching solution prevents etching defects caused by halogen precipitation, and further improves the uniformity of etching process.",
"Examples of materials used for the conductor layer to which the prevent invention can be usefully applied include Al, Mo, Ni, Ta, Pt, Ti, Pd, W, Co, Cr and the like, alloys thereof, and metallic compounds (silicide, etc.) comprising these metals and semiconductors.",
"The conductor layer can include a multi-layer structure comprising at least two layers of a metal, an alloy or a metallic compound.",
"Examples of semiconductors which can be used in the present invention include Si, Ge, GaAs, GaSb, InAs, InSb and the like.",
"The semiconductor in any one of amorphous, polycrystal and single crystal forms can be used.",
"In the description of the present invention, the statement that the width of the opening of the conductor layer is greater than that of the ohmic contact layer is intended to mean that a minimum width of the opening of the conductor layer (which is wider at an upper surface than along a depthwise direction thereof) is greater than the maximum width of the opening of the ohmic contact layer (which similarly changes in the depthwise direction thereof).",
"BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1(a) and 1(b) are graphs showing the relations between the etching rates of Al and Si and the etching agent composition according to a first embodiment of the present invention;",
"FIGS. 2(a) and 2(b) are graphs showing the relation between the average surface roughness Ra of Al and the etching agent composition;",
"FIG. 3 is a graph showing the relations between the acetic acid concentration and the etching depth and variations in etching depth in a substrate;",
"FIGS. 4(a), 4(b) and 4(c) are schematic sectional views showing the etching state of a multi-layer structure comprising a metal and a semiconductor;",
"FIGS. 5(a) through 5(e) are a schematic sectional views showing the process of manufacturing a thin film transistor substrate for a liquid crystal display according to a second embodiment of the present invention;",
"FIG. 6 is a graph showing the Id-Vg characteristics of a thin film transistor;",
"FIGS. 7(a) through 7(e) are schematic sectional views showing the process of manufacturing a TFT substrate according to a third embodiment of the present invention;",
"FIG. 8 is a sketch showing a sectional SEM image of a channel portion;",
"FIGS. 9(a) through 9(e) are schematic sectional views showing the process of manufacturing a liquid crystal display TFT substrate according to a fourth embodiment of the present invention;",
"FIG. 10 is a sketch showing a sectional SEM image of a section of a channel portion;",
"FIG. 11(a) and 11(b) through 11(d) are plan and sectional views, respectively, showing a portion of a TFT substrate according to a fifth embodiment of the present invention;",
"FIG. 12 is a schematic plan view showing the TFT substrate according to the fifth embodiment;",
"FIGS. 13(a) and 13(b) are plan and sectional views, respectively, showing the process of manufacturing the TFT substrate according to the fifth embodiment;",
"FIGS. 14(a) and 14(b) are plan and sectional views, respectively, showing the process of manufacturing the TFT substrate of according to the fifth embodiment;",
"FIGS. 15(a) and 15(b) are plan and sectional views, respectively, showing the process of manufacturing the TFT substrate according to the fifth embodiment;",
"FIG. 16 is a sectional view showing a conventional TFT;",
"FIGS. 17(a) and 17(b) are sketches showing a sectional SEM image of a channel portion of a conventional TFT;",
"FIG. 18 is a graph showing the relations between the methanol concentration and the etching depth and variations in etching depth within a substrate;",
"and FIG. 19 is a graph showing the relations between the ethanol concentration and the etching depth and variations in etching depth within a substrate.",
"DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with respect to the following embodiments.",
"It is understood that the present invention is not limited by these embodiments.",
"(Embodiment 1) According to the first embodiment of the present invention, Al or i-type amorphous silicon (a-Si) was deposited on a glass substrate by a sputtering or plasma CVD process, and the relations between the etching solution composition and the etching rate and the surface conditions were examined.",
"The results obtained are shown in FIGS. 1 to 4 and Table 1.",
"FIGS. 1(a) and 1(b) are graphs showing the relations between the etching rates of Al and i-type a-Si and the HF and HIO 3 concentrations of an etching solution.",
"As shown in FIG. 1(a), the etching rate of Al tends to increase with increases in the HF concentration, and first increase and then decrease with increases in HIO 3 concentration.",
"FIG. 1(b) shows that the etching rate of Si increases with increases in the HF concentration and HIO 3 concentration, but is saturated at a HIO 3 concentration of 0.04 mol/l.",
"FIGS. 2(a) and 2(b) show the average surface roughness Ra as functions of HF and HIO 3 concentrations when Al was etched to a depth of 200 nm.",
"FIG. 2(a) reveals that the average surface roughness decreases with increases in the HIO 3 concentration to become substantially equal to the average surface roughness (0.8 to 1.5 nm) of a substrate at 0.04 mol/l.",
"FIG. 2(b) reveals that the average surface roughness of Al is substantially equal to the average surface roughness of the substrate up to a HF concentration of 0.33 mol/l, and then increases to 10 nm or more at a HF concentration of over 0.5 mol/l.",
"FIG. 3 is a graph showing the changes in variations of the etching depth within a glass substrate, having Al deposited thereon by sputtering, which were caused by the addition of acetic acid.",
"In FIG. 3, each data point along a solid line represents the average etching depth based on measurements at five points within the substrate, and each data point along a broken line represents the variation thereof in each of static etching and rocking etching.",
"The variation is obtained by dividing a greater difference between the average and the maximum or minimum of the etching depth by the average.",
"As shown in FIG. 3, the addition of acetic acid inhibits distribution of the etching depth within the substrate.",
"FIG. 18 and 19 show the result of measurements taken when methanol and ethanol were respectively added in place of acetic acid.",
"Similar to the use of acedic acid, the addition of methanol or ethanol inhibits distribution of the etching depth within the substrate.",
"Table 1 shows the results of visual observation of the Al surface state during etching and after etching.",
"This table shows that the addition of ethanol can inhibit precipitation of a black substance, i.e., iodine.",
"TABLE 1______________________________________Solution CompositionHF HIO.",
"sub[.",
"].3 Ethanol(mol/l) (mol/l) (vol %) Surface State______________________________________0.1 0.06 0 Slight precipitation of black substance on the surface[.",
"].0.1 0.06 10 No precipitation[.",
"].0.1 0.06 20 No precipitation[.",
"].0.1 0.06 30 No precipitation[.",
"].0.1 0.12 0 Precipitation of black substance on the surface[.",
"].0.1 0.12 10 Slight precipitation of black substance on the surface[.",
"].0.1 0.12 20 No precipitation[.",
"].0.1 0.12 30 No precipitation.",
"______________________________________ An a-Si layer of 100 nm and an n + -type a-Si layer of 20 nm were then deposited by the plasma CVD method on the glass substrate (100 mm×100 mm) having a SiN x film formed thereon, and Al was subsequently deposited to 300 nm by sputtering.",
"After a resist (produced by Tokyo Oka Co., OFPR800Y-4) pattern was used to form twelve concave and twelve convex patterns measuring 2 to 20-μm square, the substrate was immersed in etching solutions having various compositions for examining changes in the etching state with time.",
"The results showed no etching defect, such as separation of the resist from the substrate, in both the concave and convex patterns.",
"FIGS. 4(a), 4(b) and 4(c) are representative views showing sections of the concave patterns, as observed using a scanning electron microscope (SEM).",
"It was found that, by using etching agents within the composition range of the present invention, etching proceeds in all patterns, as shown in FIGS. 4(a) and 4(b), and the depth of etching can be controlled by the immersion time.",
"It was also found that for example, in patterns of 5 μm square, variations in the shapes of the patterns formed are within ±0.1 μm--this indicates that extremely uniform etching can be performed using the etching agents according to the present invention.",
"It was further found that if the HIO 3 concentration is 0.008 mol/l (lower than 0.01 mol/l), abnormal etching occurs in the peripheral portion of the a-Si layer, as shown in FIG. 4(c), and only a small on-current can be obtained for an electronic device.",
"(Embodiment 2) A thin film transistor substrate for driving a liquid crystal display having 720×480 pixels was formed using the electronic device manufacturing method of the present invention, as shown in FIGS. 5(a) through 5(e).",
"Referring to FIG. 5(a), after a glass substrate 500 (Corning 7059) measuring 100×100 mm was precisely cleaned, a pattern of a transparent electrode 501 (ITO) as formed.",
"A Cr film was then formed to 100 nm by sputtering, and patterned using an etching solution ((NH 4 ) 2 Ce(NO 3 ) 6 !",
": NHO 3 : H 2 O=500 g: 1900 cc: 1870 cc) to form gate electrodes 503 and gate wiring 502.",
"Referring to FIG. 5(b), SiN x 504, i-type a-Si 505 and n + -type a-Si 506 were then deposited to a thicknesses of 300 nm, 100 nm and 20 nm, respectively, by plasma CVD.",
"Referring to FIG. 5(c), the n + -type a-Si layer and i-type a-Si layer were then separated into respective pixels using an etching solution (HF: 0.54 mol/l, HIO3: 0.04 mol/l, NH 4 I: 0.005 mol/l).",
"Referring to FIG. 5(d), after contact holes for the pixel electrodes and the gate wiring were formed, a W layer 507 and an Al layer 508 were deposited to 50 nm and 250 nm, respectively, by sputtering.",
"Referring to FIG. 5(e), in order to form source-drain electrodes and wiring and channel portions, the substrate was then immersed in an etching solution containing 0.1 mol/l of HF and 0.04 mol/l of HIO 3 for 7 minutes to continuously etch the Al layer 508, the W layer 507 and the n + -type a-Si.",
"In the final stage, a passivation layer comprising SiN x was deposited to 400 nm by the plasma CVD method, contact holes were formed on the gate wiring, and the source-drain wiring was formed to complete the thin film transistor.",
"Measurements of the Id-Vg characteristics of the thus-formed thin film transistor are shown in FIG. 6. As is obvious from FIG. 6, good results were obtained, i.e., the on-current I ON was 1.8 to 30 μA, and the off-current I OFF was several pA.",
"Although the above embodiments relate to etching for forming the channel portions, and the source-drain electrodes, for separating respective pixels and so on in the thin film transistor, etching can of course be used for other stages, for example, for forming the gate electrodes and wiring.",
"Needless to say, the present invention can also be applied to a MOS polysilicon gate, CCD, an image scanner and various multi-layer structures, each comprising a conductor layer and a semiconductor layer in various electronic devices other than the thin film transistor.",
"(Embodiment 3) An array of 100×100 TFTs were formed using the electronic device manufacturing method of the present invention in accordance with the procedure shown in FIGS. 7(a) through 7(e).",
"Referring to FIG. 7(a), after a glass substrate 700 (Corning 7059) measuring 100×100 mm was precisely cleaned, a Cr film 100 nm thick was formed by sputtering, and then patterned using an etching solution (ammonium cerium (IV) nitrate: 71% HNO 3 : H 2 O=500 g : 1900 cc: 1870 cc) to form gate electrodes 701, having a width of 7 μm, and gate wiring 702, having a width of 5 μm.",
"Referring to FIG. 7(b), a SiN x layer 703, an i-type a-Si layer 704 and an n + -type a-Si layer 705 were then deposited to 300 nm, 100 nm and 20 nm, respectively, by plasma CVD.",
"The film formation conditions for each of the films are shown in Table 2.",
"TABLE 2______________________________________ SiN.",
"sub[.",
"].2 i-type a-Si n.sup.",
"+ -type a-Si______________________________________Gas flowrate(sccm)SiH.",
"sub[.",
"].4 30 200 200H.",
"sub[.",
"].2 1000 800 800NH.",
"sub[.",
"].3 60 -- --PH.",
"sub[.",
"].3 -- -- 2Pressure 0.8 0.8 0.8(Torr)RF power (W) 400 100 100Film 300 250 250formationtemperature(°C.)______________________________________ Referring to FIG. 7(c), an n + -type a-Si layer and an i-type a-Si layer were separated to form respective TFT devices using an etching solution (HF: 0.54 mol/l, HIO 3 : 0.04 mol/l).",
"Referring to FIG. 7(d), after contact holes for the gate wiring were formed, an Al layer 706 (containing 1% Si) was deposited to a thickness of 250 nm by sputtering.",
"Referring to FIG. 7(e), in order to form source-drain electrodes and wiring and channel portions 707 (channel length 4 μm, channel width 6 μm), the Al layer and the n + -type a-Si layer were simultaneously etched by immersing the substrate in an etching solution (25° C.) containing 0.1 mol/l of HF and 0.04 mol/l of HIO 3 for 3 minutes.",
"FIG. 8 is a sketch showing an enlarged sectional SEM image of a channel portion after etching.",
"It is found from FIG. 8 that a smooth opening is formed without a gap between the Al layer and the n + -type a-Si layer.",
"After the resist was removed, a passivation layer comprising SiN x was deposited to a thickness of 400 nm, and contact holes were formed on the gate wiring and source-drain wiring to complete the thin film transistors.",
"The carrier mobility, threshold values, ON currents and OFF currents of the thus-manufactured 10 4 TFTs were measured, and variations thereof were evaluated.",
"A reliability test was also carried out, and characteristics of the device following the test were compared with the initial values.",
"The results obtained are shown in Table 3.",
"In the reliability test, the TFT substrate was placed in an environmental tester at a temperature of 85° C. and a relative humidity of 85% and allowed to stand for 1000 hours.",
"(COMPARATIVE EXAMPLE 1) For comparison, thin film transistors were manufactured by the same method as Embodiment 3 with the exception that Al and n + -type a-Si were respectively etched using the etching solutions described below.",
"In a channel portion, a gap was observed between the Al layer and n + -type a-Si layer, as shown in FIG. 17(a).",
"Etching solution for Al;",
"85% phosphoric acid: 71% nitric acid: glacial acetic acid: water =16:1:2:1 (40° C.) Etching solution for n + -type a-Si;",
"49% hydrofluoric acid: 71% nitric acid: glacial acetic acid =1:60:120 (15.2° C.) The thus-obtained sample was evaluated by the same method as Embodiment 3.",
"The results obtained are shown in Table 3.",
"TABLE 3______________________________________ ComparativeEmbodiment 3 Example 1Initial After test Initial After test______________________________________Carrier 0.8 ± 0.1 0.78 ± 0.15 0.7 ± 0.15 0.4 ± 0.2mobility(cm2/v sec)Threshold 1.0 1.0 1.5 2.5(V)ON current 2 × 10.",
"sup.",
"-16 2 × 10.",
"sup.",
"-6 1.5 × 10.",
"sup.",
"-6 2 × 10.",
"sup.",
"-6(A)OFF current 1 × 10.",
"sup.",
"-13 1 × 10.",
"sup.",
"-12 1 × 10.",
"sup.",
"-12 1 × 10.",
"sup.",
"-9(A)______________________________________ As shown in Table 3, the TFTs of this embodiment have excellent carrier mobility and TFT characteristics and exhibit less variation than the comparative example 1.",
"Therefore devices produced using the method according to the present invention exhibited superior characteristics, as compared with devices produced using the conventional method.",
"It was also found that the devices produced according to the present invention show substantially no deterioration in characteristics under severe environmental conditions and have high reliability.",
"(Embodiment 4) A thin film transistor substrate for driving a liquid crystal display having 710×480 pixels was manufactured using the electronic device manufacturing method of the present invention, as shown in FIGS. 9(a) through 9(e).",
"Referring to FIG. 9(a), after a glass substrate 900 (Corning 7059) measuring 100×100 mm was precisely cleaned, a pattern of a transparent electrode 908 (ITO) was formed.",
"Gate electrodes 901, having a width of 7 μm, and gate wiring 902 were subsequently formed by the same method as described in Embodiment 3 (above).",
"Referring to FIG. 9(b), a SiN x layer 903, an i-type a-Si layer 904 and an n + -type a-Si layer 905 were then deposited to thicknesses of 300 nm, 100 nm and 20 nm, respectively, by the plasma CVD process under the conditions shown in Table 2.",
"Referring to FIG. 9(c), the n + -type a-Si layer 905 and the i-type a-Si layer 904 were then separated to form respective pixels using an etching solution (HF: 0.54 mol/l, HIO 3 : 0.04 mol/l).",
"Referring to FIG. 9(d), after contact holes for the pixel electrodes and gate wiring were formed, a W layer 909 and an Al layer 906 were deposited to 50 nm and 250 nm, respectively, by sputtering.",
"Referring to FIG. 9(e), in order to form source-drain electrodes and wiring and channel portions (channel length 4 μm, channel width 6 μm), the Al, W and n + -type a-Si layers were continuously etched by immersing the substrate in an etching solution containing 0.1 mol/l of HF and 0.04 mol/l of HIO 3 for 7 minutes.",
"FIG. 10 is a sketch showing an enlarged sectional SEM image of the channel portion 907 after etching the n + -type a-Si.",
"Referring briefly to FIG. 17(b), it is recalled that in the conventional process, a gap 1702 was formed between the W layer and n + -type a-Si layer.",
"Referring back to FIG. 10, it is shown that, in accordance with the present invention, a gap is not formed between the Al layer and the W layer, and an smooth opening was obtained.",
"In the final stage, a passivation layer comprising SiN x was deposited to a thickness of 400 nm by plasma CVD, and contact holes were formed on the gate wiring and source-drain wiring to complete a thin film transistor substrate.",
"Evaluation of the thin film transistors of Embodiment 4, using the same methods as in Embodiment 3, showed that the thin film transistors exhibited excellent characteristics without variations, as in Embodiment 3.",
"The reliability was also excellent as in Embodiment 3.",
"A liquid crystal display was assembled using a TFT substrate, which was manufactured separately, and an image was evaluated by inputting video signals to the display.",
"The image was found to have excellent contrast and was displayed stably.",
"(Embodiment 5) In this embodiment, the TFT substrate shown in FIGS. 11 through 15 was manufactured.",
"In order to prevent breakage of transistors due to static electricity generated in the manufacturing process, a guard ring 1128 connecting source terminals 1119 and gate terminals 1118 is provided, as shown in FIGS. 15(a) and 15(b).",
"The guard ring 1128 is removed in the final stage.",
"The structure of a TFT substrate will now be described.",
"FIGS. 11(a) through 11(d) illustrate the TFT substrate of this embodiment, wherein FIG. 11(a) is a plan view and FIGS. 11(b), 11(c) and 11(d) are sectional views taken long lines A--A, B--B and C--C, respectively, in FIG. 11(a).",
"The TFT has a reverse stagger structure including a Cr gate electrode 1112 having a width of 10 μm and a thickness of 100 nm, and Cr gate wiring 1121 for supplying scanning signals to the gate electrode 1112, both of which are formed on a glass substrate 1111 (Corning Co. 7059).",
"A gate insulating film 1113 comprising a silicon nitride thin film having a thickness of 200 nm was formed on the gate electrode 1112 and gate wiring 1121.",
"A semiconductor active film 1114 having a thickness of 50 nm and comprising i-type a-Si was formed on the gate insulating film 1113, and an Al source electrode 1116 and drain electrode 1117 having a thickness of 100 nm and a width of 10 μm were further formed on the semiconductor layer 1114.",
"An n + -type a-Si ohmic contact layer 1115 having a thickness of 20 nm and containing phosphorus is formed between the semiconductor active layer 1114 and the source and drain electrodes 1116 and 1117.",
"Many thus-formed TFTs are formed in a matrix at a pitch of 100 μm on the substrate, as shown in FIG. 12.",
"On the peripheral portions of the substrate 1111 are formed source terminals 1119 for supplying image signals, provided from an external image circuit, to the source electrodes 1116 through the source wirings 1122, and gate terminals 1118 for supplying scanning signals, provided from an external scanning circuit, to the gate electrodes 1112 through the gate wirings 1121.",
"The source terminals 1119 are formed using Al, which is the same conductor material used for the source electrodes 1116 and the source wiring 1122.",
"The gate terminals 1118 also Al, and are respectively formed on the gate insulating films 1113 through the contact holes 1123 formed in the gate insulating films 1113 on the gate wirings 1121.",
"Referring back to FIGS. 11(b) through 11(d), a protective film 1127, comprising a silicon nitride film and having a thickness of 300 nm, is formed on the TFTs 1101, gate wirings 1121, source wiring 1122, source terminals 1119 and gate terminals 1118.",
"However, the surfaces of the source terminals 1119 and gate terminals 1118 are partially exposed so that they can be electrically connected to the image circuit and the scanning circuit.",
"Both widths S1 and G1 of the conductors which respectively form the source terminals 1119 and gate terminals 1118 are 50 μm, and both effective connection widths S0 and G0 of the source terminals 1119 and gate terminals 1118, from which the protective film 1127 is removed, are 42 μm.",
"Namely, the processing precision is 4 μm.",
"The method of manufacturing the TFT substrate of this embodiment is described below.",
"A Cr thin film having a thickness of 100 nm was formed by sputtering on the surface of a glass substrate 1111, upon which a pixel electrode 1120 comprising a transparent conductive film was formed.",
"A resist was formed on the surface of the glass substrate and then subjected to mask exposure, development, etching and separation treatment to form gate electrodes 1112 and gate wiring 1121 in a desired shape.",
"This is shown in FIGS. 13(a) and 13(b).",
"FIG. 13(a) is a schematic plan view, FIG. 13(b) is a sectional view taken along line A--A of FIG. 13(a).",
"A gate insulating film 1113 having a thickness of 200 nm and comprising a SiN x thin film, an i-type a-Si film 1114 having a thickness of 50 nm, and an n + -type a-Si ohmic contact layer 1115 having a thickness of 20 nm and containing phosphorus were then formed, by the plasma CVD process, on the surface of the substrate 1111 on which the gate electrodes 1112 and gate wiring 1121 were formed.",
"The semiconductor active layer 1114 and the ohmic contact layer 1115 were subjected to a photo phosphorus process to form semiconductor islands having a predetermined shape.",
"Contact holes 1123 were formed in the gate insulating film 1113 on the pixel electrode 1120 and gate wiring 1121.",
"This state is shown in FIG., 14.",
"FIG. 14(a) is a schematic plan view, and FIG. 14(b) is a sectional view taken along line A--A in FIG. 14(a).",
"An Al thin film having a thickness of 100 nm was formed on the substrate including the ohmic contact layer 1115 by the sputtering method using an Al target containing 1% Si.",
"A resist film 1124 was formed on the surface of the Al thin film, exposed and developed, and the Al and ohmic contact layer were then etched by the same method as Embodiment 1 to form the source electrodes 1116, source wiring 1122, source terminals 1119, drain electrodes 1117 and guard ring 1128 for electrically connecting the source terminals 1119 and gate terminals 1118, gate terminals 1118 and channels 1126, as shown in FIGS. 15(a) and 15(b).",
"At this time, the gate terminals 1118 were formed by processing the conductor so as to completely cover the gate wiring 1121 below the contact holes 1123 with Al wiring.",
"FIG. 15(a) is a schematic plan view, and FIG. 15(b) is a sectional view taken along line A--A in FIG. 15(a).",
"In this embodiment, as shown in FIGS. 15(a) and 15(b), the ohmic contact layer 1115 is electrically connected to the source wiring 1122, source terminals 1119, guard ring 1128, gate 1121 and s 1118, gate wiring 1121 and gate electrodes 1112 through the source electrodes 1118 located immediately above the ohmic contact layer.",
"However, since all surfaces of the gate terminals 1118, gate wiring 1121 and gate electrodes 1112 are covered with the gate insulating film 1113 serving as an insulator or the conductor which forms the source wiring 1122, and all conductors which form the source wiring 1122, source terminals and guard ring 1128 are covered with the resist film 1124 serving as an insulator.",
"Namely, all conductive members electrically connected to the ohmic contact layer 1115 are covered with an insulator.",
"When the ohmic contact layer 1115 is treated with an etching solution containing an electrolyte, therefore, the ohmic contact layer 1115 does not form a battery with another conductor, and is not abnormally etched due to the battery effect.",
"In etching of the ohmic contact layer 1115, it is possible to prevent side etching due to the battery effect by covering the layers electrically connected to the ohmic contact layer.",
"Referring again to FIGS. 11(b) through 11(d), a protective film 1127 comprising a silicon nitride thin film was then formed, and a resist film was formed on the surface thereof and then subjected to mask exposure, development, etching and separation treatment to expose the source terminals 1119 and gate terminals 1118.",
"Since the gate terminals 1118 and source terminals 1119 were formed on the gate insulating film 1113, the gate terminals could be formed only by removing the protective film 1127.",
"The guard ring 1128 for connecting the gate wiring 1121 and source wiring 1122 was then removed to form the TFT substrate shown in FIG. 11(a).",
"The thus-formed TFT substrate 1111 includes a plurality of TFTs arranged in a matrix with a pitch of 100 μm.",
"Along a periphery of the substrate 1111 are arranged the source terminals for receiving the video signals transmitted from an external video circuit to the source electrodes 1116 through the source wiring 1122, and the gate terminals 1118 for receiving scanning signals supplied from an external scanning circuit to the gate electrodes 1112 through the gate wiring 1121.",
"The etching agent of the present invention enables fine patterning of a multi-layer structure comprising a conductor and a semiconductor with a single etching agent.",
"Since this patterning has high uniformity, it can preferably be applied to manufacture of electronic devices having a large area and high density.",
"The electronic device of the present invention exhibits excellent characteristics, less variations, and high reliability.",
"The present invention can provide many elements such as TFTs which are required to operate at high speeds and have uniform characteristics.",
"The electronic device manufacturing method of the present invention provides a simple manufacturing process with high yield, as compared with conventional methods.",
"It is thus possible to decrease the production costs of various electronic devices using the above-described methods pertaining to the present invention."
] |
RELATED APPLICATIONS
[0001] This application is a continuation-in-part application of Ser. No. 10/315,624 filed Dec. 10, 2002 entitled, “WIRELESS NETWORK PROVIDING DISTRIBUTED VIDEO/DATA SERVICES”. The present application is also related to Ser. No.______ , filed Feb. 14, 2003.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of transmission of digital data; more specifically, to satellite communication systems and networks for distributing video data and for providing interactive services to geographically dispersed clients.
BACKGROUND OF THE INVENTION
[0003] Satellite communications systems have been widely deployed over the past several decades. By way of example, Direct Broadcast Satellite (DBS) services have increasingly expanded to provide a variety of video program services directly to people's homes, apartments, and offices. In a conventional direct-to-home (DTH) satellite communication system, one or more telecommunications satellites in geosynchronous orbit receive media content from a broadcast “uplink” center. The satellite then radiates microwave signal beams to send the media content across a geographical region of the planet. For example, in the case of satellite service providers like DirectTV® video programs are broadcast across a wide region of the continental United States from several satellites in geosynchronous orbit above the Earth's equator.
[0004] Subscriber homes in the U.S. typically utilize an outdoor antenna dish mounted to their roof or an exterior wall to receive the satellite-transmitted signals. A satellite receiver or set-top box within the home is connected to the antenna for acquiring the satellite carrier signal and displaying the video program content received from the satellite transmission. As is well known, the satellite receiver may include decompression, decryption, decoder, demodulation and other circuitry for converting the received signals into a format (e.g., high definition television (HDTV), standard definition television (SDTV), etc.) suitable for viewing on a display device by the subscriber. For example, for direct-to-home digital satellite carriers which conform to Digital Video Broadcast (DVB) standards, the satellite receiver is configured to receive a set of parameters that may include the polarization, symbol rate, forward error correcting (FEC) rate and frequency to acquire the satellite digital carrier. U.S. Pat. Nos. 6,473,858, 6,430,233, 6,412,112, 6,323,909, 6,205,185, and 5,742,680 describe various conventional satellite communication systems that operate in this manner.
[0005] Satellite transmissions are often grouped in channel sets, wherein each channel set spans a certain transmit band. The channel sets are typically isolated by different electromagnetic polarizations. For instance, channel sets may be transmitted with linear polarization (i.e., horizontal or vertical) or circular polarization (i.e., left-hand or right-hand). These channel sets are detected on a polarization-sensitive antenna assembly through a low-noise block converter (LNB) mounted opposite a parabolic antenna dish. The LNB may be configured, for example, to detect the horizontal or vertical polarized signals reflected from the antenna dish. The LNB connects to the satellite receiver unit or set-top box located inside the subscriber's home via a coaxial cable.
[0006] In some receiving systems two LNBs are provided to receive both channel sets so that multiple television sets within a home may view different program channels simultaneously. Examples of different satellite data receiving systems are found in U.S. Pat. Nos. 6,424,817 and 5,959,592.
[0007] One of the problems with satellite communication systems is that they generally require an unobstructed line-of-sight between the orbiting satellite and the receiving antenna dish. In the United States, for instance, satellites typically orbit above the equator and are therefore “seen” by the antenna above the southern horizon. A home in a densely populated metropolitan region, however, may have its view of the southern sky obstructed by a tall building. In other cases, apartment dwellers living in units on the north side of a building may be precluded from mounting an antenna anywhere to receive satellite transmissions from a satellite orbiting above the southern horizon.
[0008] In other cases, landlords who own apartment buildings containing multiple units may be reluctant to permit tenants to mount multiple antenna dishes on their structure or route cable wires through the exterior and interior of the building. Routing of wires is also a problem in homes, particularly when multiple televisions are to receive programming services. The line-of-sight requirement and the problem of multi-dwelling units (MDUs) have therefore limited the number of homes that can receive digital services from satellite vendors.
[0009] An additional problem that satellite vendors generally face is the difficulty of providing interactive data services to their customers. Some specialized satellite service providers offer two-way data services, but these systems require the subscriber to purchase a fairly large antenna dish (e.g., 3-5 feet wide) with increased power demands for uplink transmission to the satellite. Another drawback is the inherent latency associated with signal transmission from Earth to the orbiting satellite, and then back down to Earth. This latency can produce sluggish system performance as compared to terrestrial cable systems, for example, when the user wants to access a web page containing large amounts of content and data.
[0010] Thus, there is a pressing need for new apparatus and methods for distributing satellite services and video content to the general population on an expanded basis. There is also a need for a communication network that provides additional services, such as interactive data services, to subscribers at a competitive cost and at a high performance level.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present invention will be understood more fully from the detailed description that follows and from the accompanying drawings, which however, should not be taken to limit the invention to the specific embodiments shown, but are for explanation and understanding only.
[0012] [0012]FIG. 1 is a conceptual diagram of a satellite communication system in accordance with one embodiment of the present invention.
[0013] [0013]FIG. 2 is a perspective view of an antenna assembly according to one embodiment of the present invention.
[0014] [0014]FIG. 3 is a more detailed view of the components comprising the signal unit of the antenna assembly shown in FIG. 2.
[0015] [0015]FIG. 4 is an example showing an application of the present invention to a multi-dwelling unit.
[0016] [0016]FIG. 5 illustrates the spectrum band utilized for cable communications with the wireless transceiver in accordance with one embodiment of the present invention.
[0017] [0017]FIG. 6 depicts the type of information and signals transmitted between the network interface/satellite receiver device and antenna assembly according to one embodiment of the present invention.
[0018] [0018]FIG. 7 shows the example of FIG. 4 optionally including a mass storage repository according to another embodiment of the present invention.
[0019] [0019]FIG. 8 shows an alternative embodiment of the present invention, wherein a wireless transceiver is incorporated in a distribution box.
[0020] [0020]FIG. 9 shows an example of a wireless transceiver functioning as a free-standing repeater in accordance with an embodiment of the present invention.
[0021] [0021]FIG. 10 is an example of an antenna assembly according to another embodiment of the present invention.
[0022] [0022]FIG. 11 illustrates a wireless network that carries presentation layer content provided by a source to multiple destination devices in accordance with an embodiment of the present invention.
[0023] [0023]FIG. 12 illustrates a wireless network that seamlessly integrates Internet traffic with video content in accordance with an embodiment of the present invention.
[0024] [0024]FIG. 13 is a circuit block diagram of the basic architecture of a DBS tuner according to one embodiment of the present invention.
[0025] [0025]FIG. 14 is a circuit block diagram of the basic architecture of a cable television tuner/router in accordance with one embodiment of the present invention.
[0026] [0026]FIG. 15 is a circuit block diagram of the basic architecture of a wireless receiver in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
[0027] The present invention is a pioneering advancement in the field of multimedia communication systems. By integrating a wireless transceiver into a satellite antenna assembly, the present invention provides, for the first time, a wireless local area network (WLAN) which both distributes a wide range of video services (digitally-encoded broadcast services, pay-per-view television, and on-demand video services, etc.) and provides two-way (i.e., interactive) data services to individuals located across a wireless coverage region.
[0028] In the following description numerous specific details are set forth, such as frequencies, circuits, configurations, etc., in order to provide a thorough understanding of the present invention. However, persons having ordinary skill in the satellite and communication arts will appreciate that these specific details may not be needed to practice the present invention. It should also be understood that the basic architecture and concepts disclosed can be extended to a variety of different implementations and applications. Therefore, the following description should not be considered as limiting the scope of the invention.
[0029] With reference to FIG. 1, a conceptual diagram of a satellite communication system in accordance with the present invention is shown comprising a telecommunications satellite 12 positioned in a fixed, geosynchronous orbital location in the sky over the particular geographical region of the Earth. Satellite 12 utilizes standard solar panels to generate power for the satellite's resources which includes one or more transponders that provide telecommunication links (i.e., “uplinks” and “downlinks”) to Earth-based stations and receivers.
[0030] For example, FIG. 1 shows a large antenna 10 that broadcasts video programs from an uplink center to satellite 12 . This uplink signal is represented by arrow 11 a. Satellite 12 transmits the broadcast signal (e.g., downlink 11 b ) across a coverage region of the Earth, where it may be received at a home 14 equipped with an outdoor antenna assembly coupled to electronics for displaying the video programs. The antenna assembly, which is also shown in FIG. 2, includes a support 21 attached to a parabolic or concave reflector dish 16 , which is aimed to the location in the sky where satellite 12 is positioned in geosynchronous orbit above the earth. Support 21 may include a base plate 13 to facilitate mounting of the antenna assembly to the exterior (e.g., roof) of house 14 . An arm 15 , attached to either dish 16 or support 21 , extends to position a signal unit 18 at a focal point of the reflector dish 16 . An antenna 77 for wireless transmissions is also shown attached to unit 18 . Unit 18 converts the electromagnetic radiation reflected from dish 16 into electrical signals carried by one or more conductors 20 to a network interface unit 23 or satellite receiver 24 within home 14 . Receiver 24 , for example, converts the satellite transmission signals into a format for display on television 26 .
[0031] With reference to FIG. 3, there is shown an exemplary embodiment of signal unit 18 in accordance with the present invention comprising a pair of low-noise block converters (LNBs) 72 & 73 and a wireless transceiver 71 mounted in a case or housing 76 . Wireless transceiver 71 has an associated antenna 77 to effectuate wireless transmissions. Feed horns 74 and 75 associated with LNBs 72 & 73 , respectively, protrude from a side of housing 76 that is positioned nearest to reflector dish 16 . Alternatively, the signal unit 18 may utilize a single feed horn coupled to one or more LNBs. Other embodiments may include multiple transceivers, each having its own associated wireless antenna. For instance, an alternative embodiment may comprise a pair of LNBs with an associated pair of wireless transceivers, each having its own wireless antenna.
[0032] In this example, LNBs 72 & 73 may be configured to receive horizontally and vertically polarized satellite transmission signals. Cable 20 connects with the LNBs and transceiver 71 . (It should be understood that within the context of this disclosure, the term “cable” is used to refer to one or more wires and that such wires may comprise coaxial wires of a type known as RG-6, or a similar type.)
[0033] It is appreciated that in other embodiments unit 18 may comprise a single LNB and a wireless transceiver. In still other embodiments, unit 18 may include four or more LNBs and one or more wireless transceivers mounted together.
[0034] [0034]FIG. 10 shows another exemplary embodiment of an antenna assembly in accordance with the present invention comprising side-by-side LNBs 172 & 173 mounted at the end of arm 115 attached to reflector dish 116 . A pair of wireless transceivers (not shown) associated with LNBs 172 & 173 are coupled to antennas 177 & 178 , respectively affixed to LNBs 172 & 173 . Feed horns 174 and 175 respectively attached to LNBs 172 & 173 are shown positioned to receive the satellite transmission signal reflected from dish 116 . Support member 121 attaches to reflector dish 116 at one end, and to a bracket 122 at the opposite end. Bracket 122 may include screw holes or other conventional means for mounting the antenna assembly to a permanent fixture of building, e.g., a wall, roof, etc. Support member 21 and bracket 122 may also include adjustment apparatus for properly aiming reflector dish 116 at an orbiting broadcast satellite positioned at a certain point in the sky.
[0035] According to one embodiment of the present invention, wireless transceiver 71 operates in compliance with IEEE specification 802.11a, 802.11b, 802.11g, etc., to provide high-speed networking and communication capability to computers, televisions, and other devices compatibly equipped to receive such wireless signals. Other embodiments may operate in compliance with variant specifications that are compatible with IEEE specification 802.11a, 802.11b, or 802.11g, and which provide for wireless transmissions at high-bandwidth video data rates (e.g., about 2 Mbps or greater). For the purposes of the present application, IEEE specification 802.11a, 802.11b, 802.11g, and Industrial, Scientific, and Medical (ISM) band networking protocols are denoted as “802.11x”. Other non-ISM bands wireless network protocols could be utilized as well. Transceiver 71 facilitates network connectivity to users located within a surrounding range, allowing them to receive satellite broadcast programs, pay-per-view services, on-demand video, Internet access, and other interactive data services, thus obviating the need for a wired connection to individual users.
[0036] In the example of FIG. 1, transceiver 71 operates over the license-free 5 GHz band (e.g., 5725 MHz to 5850 MHz) to provide upwards of 54 Mbps of bandwidth in good transmission conditions. IEEE specification 802.11a allows for a high-speed wireless transmission of raw data at indoor distances of up to several hundred feet and outdoor distances of up to ten miles, depending on impediments, materials, and line-of-sight. 802.11a has twelve channels (eight in the low part of the band for indoor use and four in the upper for outdoor use) which do not overlap, allowing for dense installations. According to the present invention, individual users may receive transmissions from transceiver 71 using hardware equipment available from a number of vendors. For example, Proxim, Inc. manufactures and sells the Harmony 802.11a PCI card that provides wireless broadband networking at a data rate of 54 Mbps.
[0037] In another embodiment, transceiver 71 operates in compliance with IEEE specification 802.11g over the license-free 2.46 GHz band.
[0038] As shown in FIG. 1, wireless signals 17 may be transmitted from unit 18 of the antenna assembly mounted on house 14 to a nearby laptop computer 25 installed with a PC card or a PCI card that is 802.11x compliant. Similar equipment may be installed into slots of a personal computer 38 or a television 37 to provide connectivity to network services in a house 36 that is located within the neighboring range of the wireless transceiver, despite the fact that house 36 does not have a satellite antenna dish or is not otherwise wired to receive such services. This means, for example, that someone may access their electronic mail from any location within the full extent of the wireless network since the transmission signals pass easily through walls and glass.
[0039] In the example of FIG. 1, house 36 may be located outside of the signal range of wireless transmission signals 17 , but within the range of the wireless signals 27 from the transceiver mounted in unit 28 of antenna assembly 26 on top of a neighboring house 34 . In such a case, the transceiver within unit 28 may function as a repeater or hub for house-to-house transmissions; that is, to relay the media content and interactive services provided at home 14 to users at home 36 and elsewhere. Through the use of transceivers 71 functioning as repeaters, content and two-way data services may be distributed to end users located at considerable distances from the original service connection source. In other words, a neighborhood of antenna assemblies that include wireless transceivers can be used to create a network that provides distributed video program and interactive data connectivity. Homes installed with an antenna assembly according to the present invention may still act as a house-to-house repeater for the neighborhood as part of a “roof-hopping” scheme, even though they may not have an immediate need for wireless communications, Later on, those homes may simply add the appropriate hardware (e.g., wireless communication card, network interface box, etc.) to take advantage of the additional services such as interactive data provided by wireless connectivity.
[0040] It is appreciated that wireless transceiver 71 need not be physically located on or inside of signal unit 18 . In FIG. 8, for example, a wireless transceiver connected to wireless antenna 111 is incorporated into a distribution box 110 . Distribution box 110 may splice into cable 20 at any point, and therefore may be remotely located some distance from the antenna assembly comprising reflector 16 , arm 15 , and signal unit 18 . In addition to providing a point for wireless transmissions, distribution box 110 may also function as a splitter or switching device for the signals carried on cable 20 .
[0041] It should be further understood that according to the present invention, the individual satellite antenna assemblies need not be located on homes or other buildings; instead, they may be positioned on existing telephone poles, or mounted on other structures with dedicated, stand-alone hardware. Additionally, a plurality of stand-alone wireless transceivers that function solely as signal repeaters may be distributed in a geographic region or throughout a large building wherever power is available to provide network connectivity that extends throughout the region or area.
[0042] For example, FIG. 9 shows a free-standing antenna assembly according to one embodiment of the present invention. The antenna assembly, which includes a signal unit 18 with wireless antenna 77 positioned at the distal end of arm 15 opposite reflector 16 , is mounted on a pole 113 along with an associated solar cell panel 115 . Solar cell panel 115 provides power to support the 802.11x wireless transceiver operating as a repeater on an around-the-clock basis. Solar cell panel 115 may be dimensioned sufficiently large enough, and may be coupled to a storage cell battery (not shown) mounted on the pole or in back of the panel so as to provide power “24×7” to the antenna assembly based on minimum daily solar radiation averages for the particular geographic location.
[0043] In an alternative embodiment, the concave or parabolic surface of reflector 16 may incorporate an array of solar cells. For example, solar cells may cover a portion of the reflector surface to power the wireless transceiver(s) of the satellite antenna assembly, thus obviating the need for a separate solar cell panel. In another implementation, the entire surface of the satellite dish reflector is covered with solar cells to provide power to the wireless transceiver or wireless satellite tuner.
[0044] [0044]FIG. 4 shows a large apartment building 50 with a satellite antenna assembly that includes a reflector dish 56 and a wireless transceiver mounted in signal unit 58 . (The electronics that provides power and command/control signals for the antenna assembly is not shown in FIG. 4 for clarity reasons.) A series of repeaters 60 a - 60 e are located on various floors throughout the building to distribute signal transmissions to/from the transceiver of unit 58 to each of the multiple apartment units within building 50 . A two-way data service connection (e.g., DSL) is provided to an 802.11x wireless transceiver/repeater 60 e. Thus, subscribers located anywhere within building 50 may connect to the DSL service via this wireless transmission. Similarly, two-way data service connectivity is provided to others within the range of the transceiver of unit 58 of the antenna assembly mounted on the roof of building 50 (or to anyone in a neighboring region reached via roof-hopping signal repeating). In a metropolitan region a single satellite antenna assembly with integrated wireless transceiver can therefore distribute high bandwidth services to residents of neighboring buildings, even though those neighboring buildings may not have a satellite antenna or be otherwise wired to receive those services.
[0045] Additionally, wireless transceiver/repeater 60 e may be connected to receive video content from some media source, e.g., a Digital Versatile Disk (“DVD”) player, or cable television programming. In the later case, for instance, wireless transceiver/repeater 60 e may include a cable modem equipped with an 802.11x transmitter. These alternative or additional services may then be distributed in a similar manner described above.
[0046] [0046]FIG. 1 also illustrates another extension of the network provided by the present invention, wherein media content may be distributed to an 802.11x compliant receiver unit 40 installed in the trunk of an automobile 39 , or other mobile vehicle. Unit 40 , for instance, may include a hard disk drive to store video programs received from wireless transmission signals 17 when automobile 40 is parked, say, overnight in a garage. These programs can then be viewed by rear-seat passengers on a trip the following day.
[0047] With continued reference to the example of FIG. 1, two-way data service is shown being provided by cable 19 connected to a network interface unit 23 . Cable 19 may provide a direct subscriber line (DSL) connection, for instance, which may then be distributed to subscribers in the surrounding range of wireless signals 17 . Thus, according to the present invention a user of laptop computer 25 , who may be located outdoors or at a nearby café, can access the Internet, watch a pay-per-view film, or receive a multitude of other multimedia services.
[0048] Alternatively, network interface unit 23 may be connected to a cable broadcast service provider (e.g., cable television) through an Ethernet or Universal Serial Bus (USB), or similar connection, thereby enabling wireless access of those cable services to subscribers within the range of the wireless network. This means that a subscriber may watch their favorite television program or a pay-per-view movie from a laptop computer or television while outdoors, in a café, or in some other building, within the wireless coverage region without the need for a direct-wired cable connection. Distribution of cable services may be implemented with a cable modem device that includes an 802.11x transmitter. It is appreciated that additional circuitry for encrypting the video and data information may also be included to thwart pirates and interlopers.
[0049] Network interface unit 23 provides power to and communicates with transceiver 71 of unit 18 via cable 20 . Although the embodiment of FIG. 1 shows network interface unit 23 connected to satellite receiver 24 , alternatively both devices may be integrated in to a single device 30 , as shown in FIG. 6. In either case, the network interface unit communicates with the transceiver using spectrum that is not otherwise utilized in cable 20 . Since satellite receivers tend to operate in the spectrum from about 1.2 GHz to about 2 GHz, the spectrum below 1.2 GHz, down to about 40 MHz, may be used for communications with the wireless transceiver. This spectrum band is illustrated in FIG. 5.
[0050] It should also be understood that although FIG. 1 shows a direct connection between satellite receiver 24 and television 26 , alternatively, video services may be provided to any 802.11x compliant television (e.g., installed with an 802.11x adapter card) located within the house or surrounding wireless coverage region.
[0051] [0051]FIG. 6 depicts the type of information and signals carried by cable 20 between network interface/satellite receiver device 30 and unit 18 of the antenna assembly of the present invention. Many techniques are well known in the electronics and communications arts for transmitting such signals, such as QPSK and QAM modulation. As shown, satellite signals received by the antenna assembly are provided to device 30 via cable 20 . Additionally, wireless transmissions received by transceiver 71 are coupled to device 30 . Device 30 provides power to the LNBs and transceiver, LNB configurations signals, transceiver command and control signals, and wireless data via cable 20 . By way of example, FIG. 6 shows device 30 having a DSL connection that may provide Internet access to users within the surrounding range of the transceiver of unit 18 .
[0052] [0052]FIG. 7 illustrates the MDU example of FIG. 4, but with a specialized mass storage repository unit 64 installed on the rooftop of building 50 . Repository unit 64 comprises a number of hard disk drives (HDDs) having a large total storage capacity (e.g., 10 terabytes) arranged as a RAID (“Redundant Array of Inexpensive Disks”) 65 that functions as a media library apparatus. An 802.11x compliant wireless transceiver 66 is also included in repository unit 64 along with various electronics 67 coupled to both RAID 65 and transceiver 66 . Electronics 67 may comprise a microcomputer including a processor (CPU), a ROM, a RAM, etc., to control the data read/write processing by the HDDs and to control the operation of transceiver 66 . Electronics 67 may also include data compression/decompression circuitry for certain video and data applications. Still other embodiments may include encryption/decryption circuitry for receiving and sending transmissions in a secure manner. The RAID 65 , transceiver 66 , and electronics 67 are all housed in rugged, weather-resistant enclosure providing a suitable environment for the HDDs and the other circuitry.
[0053] Repository unit 64 may communicate via wireless transmission utilizing wireless transceiver 66 connected to a wireless antenna 68 mounted on top of unit 64 . Alternatively, unit 64 may be coupled with signal unit 58 via a wire connection 69 (e.g., CAT-5) to utilize the transceiver in signal unit 58 for wireless communications.
[0054] In an alternative embodiment, repository unit 64 may be attached to the satellite antenna assembly to directly utilize the wireless transceiver installed in signal unit 58 .
[0055] The purpose of RAID 65 is to store recorded media content (e.g., pay-per-view movies, videos, DVDs, special event programs, etc.). This content can be accumulated over time in a “trickle feed” manner from wireless transceiver 66 , which may receive content from various sources such as satellite transmissions, media players, cable television, Internet, etc. Over time, repository unit 64 may store such large volumes of video programming. Anyone having the capability to access the wireless network can pay a fee to receive a particular show, movie, or viewable program stored in repository unit 64 on an on-demand basis.
[0056] Additionally, because of the interactive capabilities of the wireless network, the subscriber or user may communicate with unit 64 to provide commands such as “pause”, “fast forward”, “rewind”, etc. Indeed, because of the large storage space available, live broadcast programs available through the WLAN described previously may be manipulated using such commands, thereby providing enhanced viewing flexibility to the user. Hard disk drive failures, which often plague in-home digital video recorders (DVRs), are not a problem because of the redundancy protection built into the RAID. Should a particular hard disk drive fail during operation, the remaining disk drive units simply take over until the repository unit can be serviced, at which time the failed drive can be replaced.
[0057] Repository unit 64 may also function as an archive storage apparatus for individuals within a local area to utilize as a storage facility for back-ups of personal data. For example, personal data such as photographs, important documents, books, articles, etc. may be transferred into a reserved space in the RAID 65 . Various well-known security features may be built into repository unit 64 to maintain personal security of the backed-up data for each user.
[0058] It is also appreciated that repository unit 64 may be physically located somewhere other than on the rooftop of a building of MDUs. For instance, instead of being attached to, or nearby, a rooftop antenna assembly, repository unit 64 may be located in a top floor space, in a basement, or in a ground level facility.
[0059] With reference now to FIG. 11, there is shown a wireless local area network (WLAN) having a topology comprising one or more access points or wireless repeaters that provides a wireless network transmission backbone 125 that carries data downstream to a variety of wireless destination devices located throughout a building, e.g., a home or office environment. The access points or repeaters of wireless network backbone 125 may include 802.11x transceivers for transmitting data upstream from the destination devices to tuner 126 or the source broadband network (e.g., Internet). The WLAN of FIG. 11 comprises a tuner 126 having a connection to a video/data source, such as cable television or satellite broadcast service provider. Tuner 126 receives the content provided by the source and sends it across backbone 125 to one or more wireless destination devices, which may include, by way of example, a PDA 127 , laptop computer 130 , and a wireless receiver 128 coupled to SDTV/HDTV 129 . In this example, PDA 127 and laptop computer 130 are each configured with wireless transceiver cards for receiving and transmitting data across the wireless network.
[0060] Practitioners in the art will further appreciate that tuner 126 may also digitize analog video, decode it, and compress the received source data prior to transmission across the wireless network, in addition to receiving compressed digital video. In the case where compressed video is transmitted by tuner 126 , receiver 128 decompresses the data as it is received. Alternatively, decompression circuitry may be incorporated into television 129 (or into an add-on box) that performs the same task. Tuner 126 may include electronics for tuning the analog channels provided by a cable service provider as well as the digital channels provided by either cable or satellite service providers. Tuner 126 may also include, or be adapted to receive, a smart card having decryption information for decrypting the satellite and/or cable signals received. In other words, the wireless network of FIG. 11 may be configured to provide a media layer that includes encryption and entitlement information.
[0061] Alternatively, encryption/decryption key information may be stored within each of the destination devices. For example, receiver 128 may include proprietary hardware/firmware or run software to exchange encryption key information or otherwise entitle receiver 128 to receive a proprietary signal. Similarly laptop 130 may securely run software that will honor network entitlements. As a subscriber to a particular satellite or cable service, a user may watch whatever content that may be received on their wireless receiver, laptop computer, PDA, etc. That is, the entitlements may be securely transferred to any destination device owned by a subscriber. Unlike conventional satellite or cable technologies in which the same encryption key is broadcast to everyone, in the embodiment of FIG. 11, the source provider transmits a unicast (i.e., point-to-point) transmission through a secure link with an encryption key specific to a particular receiver (or other destination device). Individual encryption links are provided as opposed to an overall, universally-encrypted broadcast signal.
[0062] By way of further example, after decrypting the video/data content received from a satellite or cable service provider, tuner 126 may re-encrypt that content utilizing public key encryption before wirelessly transmitting the video/data from tuner 126 to receiver 128 across backbone 125 . Re-encryption thwarts interlopers or unscrupulous hackers from stealing the signal. Entitlement information, such as a list of authorized users or subscribers, may be specific to each receiver 128 . In other words, tuner 126 may broadcast the encrypted cable video or satellite video signal across backbone 125 , but receiver 128 will have to be registered with the satellite or cable company, or be otherwise entitled, in order for the video content to be displayed on SDTV/HDTV 129 .
[0063] Still another possibility is for the cable or satellite company to grant an entitlement to tuner 126 that allows a certain limited number of data streams (e.g., three or four) to be transmitted in a particular household or office environment, regardless of the number of media destination devices that actually receive the media content. This is simply another way to restrict distribution of the media content.
[0064] It should be understood that tuner 126 of FIG. 11 may be incorporated into the antenna assembly shown in any of the previous Figures. That is, tuner 126 may be included in an antenna assembly mounted to the roof or side of a building. In such configuration, the network of the present invention enables broadband video for the entire local area. In other words, high bandwidth video content is introduced locally in the network. Internet connection data can also be inserted locally via a connection to a T1, TS3, DSL, or other similar line. Because satellite data is broadcast simultaneously across a wide geographic area, the present invention obviates the need to introduce video for each local area from the root of tree-like distribution network. Instead, the video content for the network of the present invention can be inserted locally through satellite antenna assemblies, resulting in a very robust, ad hoc network.
[0065] Once tuner 126 has tuned (and possibly decrypted) the video/data content provided by the source, it functions as a wireless server to distribute that video/data content to authorized users connected to the wireless network. In addition to video and data content, the wireless network shown in FIG. 11 may also carry presentation layer information to multiple destination devices. This allows a network operator to define how they want the user interface presented with the transmitted content to be displayed. For example, the network operator might permit a user to view movies with a certain set of presentation controls (e.g., pause, rewind, fast-forward, and so forth). Another possibility is to include controls that allow a viewer to review a synopsis of the film, or information about the actors, much like the presentation layer sometimes used for DVDs. In this manner, a DVD-like experience can be created at the front end of an entire cable or satellite network or system.
[0066] Presentation layer data may be loaded into receiver 128 , which would then download the video/data transmitted by tuner 126 across backbone 125 into an internal RAM, or Flash memory, and overlay the presentation layer information on top of the media content. Thus, receiver 128 may take the various types of data it receives (video, audio, presentation, etc.) and reduce it to a particular format for display or reproduction. The particular format may include the type of user interface presented when certain types of content are displayed.
[0067] Those of ordinary skill in the art will further appreciate that the wireless network of the present invention is client or destination device independent. That is, it does not matter to the network what type of device is at the destination end receiving the transmitted media content. Video and graphics content carried on the wireless local area network of the present invention can play on multiple types of television, computers (e.g., Macintosh® or PC), different MP3 players, PDAs, digital cameras, etc. By way of example, any PC or Mac equipped with a 2.4 GHz band wireless transceiver card can detect the presence of the wireless network. Once it has detected the running wireless network, it may download a driver that contains the necessary security and protocol information for accessing the media content. Readily available software, such as RealPlayer®, QuickTime®, or Windows® MediaPlayer, may be used to play content provided through the network.
[0068] [0068]FIG. 12 illustrates a wireless network that seamlessly integrates Internet traffic with video content in accordance with another embodiment of the present invention. In addition to the devices shown in FIG. 11, the WLAN of FIG. 12 further includes a cable/DSL wireless router 133 and wireless disk server 131 coupled to backbone 125 . Router 133 transmits data from a conventional cable or DSL data network across backbone 125 to the various destination devices located within the range of the WLAN. Data may also be transmitted back to the cable/DSL network from each of the destination devices via backbone 125 and router 133 . The cable/DSL data integrates seamlessly with the wireless data stream so that, for example, one user may download data from the Internet while another user watches a movie or television program. In other words, tuner 126 and router 133 share the same spectrum.
[0069] Wireless disk server 131 comprises one or more disk drive units that function as a file server controlled by a microcontroller or other controller unit that may include a 802.11x transceiver, a RAM, ROM, CPU, Flash memory and other electronic devices for receiving data transmitted across backbone 125 and storing that data on a magnetic or magneto-optical recording media. Disk server 131 also functions to retrieve data previously stored for transmission on the wireless network to other requesting devices, such as laptop computer 130 .
[0070] Disk server 131 provides archival storage of video and other data for the wireless local area network, and also facilitates certain presentation layer features, such as digital video recording (DVR) capabilities. For instance, video data may be stored on a magnetic disk media in server 131 for later on-demand viewing with full playback, pause, rewind, fast-forward, etc., command features. Essentially, disk server functions as a mass repository unit in the same manner as repository unit 64 previously described in conjunction with FIG. 7. Disk server 131 , however, need not be a secure device. The reason why is because the WLAN shown in FIG. 12 writes/reads data to the disk storage of server 131 in encrypted form. This data can only be decrypted by a device having the proper entitlements. In other words, the same entitlements that allow a user or subscriber to watch a movie broadcast by a service provider such as the Dish® network, allow that same user to watch a previously recorded movie (stored to disk server 131 ) received from a Dish® transmission. Put another way, disk server 131 does not need encryption/decryption capabilities, and may comprise an ordinary disk server configured for wireless communications.
[0071] By that same token, any computer that is within the transmission range of the wireless network of the present invention can use that computer's internal disk drive for storage of video/data. Note that the archived video/data may be unusable without the proper entitlements; that is, to be able to play back a stored video program a user would need a subscription to the broadcast service, or other appropriate entitlement.
[0072] With reference now to FIG. 13, a circuit block diagram showing the architecture of a DBS tuner according to one embodiment of the present invention is shown including a CPU 144 , a RAM 145 , a Flash ROM 146 , and I/O ASIC 147 coupled to a system bus 155 . Also coupled to system bus 155 are a plurality of transceivers, which, in this particular embodiment, include a 5 GHz downstream transceiver 156 , and a 2.4 GHz transceiver 157 , both of which are coupled to an antenna 160 . (An upstream transceiver is not needed at the source end.) Additional transceivers operating at different frequencies may also be included. In this implementation, transceiver 156 operates in compliance with IEEE specification 802.11a to run with an effective throughput of 36 Mbps for transmissions on backbone 125 . Transceiver 157 is 802.11g-compliant and also runs with an effective throughput of 36 Mbps to connect to any local devices operating in the 2.4 GHz band.
[0073] CPU 144 controls the transmission of the data packets, utilizing RAM 145 for both program execution, and for buffering of the packets as they are received from the source feed before they are sent out to the downstream side, i.e., toward the destination. Flash ROM 146 may be used to hold software and encryption key information associated with secure transmissions, for example, to insure that the network users are authorized users of satellite or cable subscriber services.
[0074] In the embodiment of FIG. 13, a 1394 connector interface 151 provides a Firewire® port (coupled through a 1394 PHY physical interface) to I/O ASIC 147 . Also coupled to I/O ASIC 66 is a pushbutton switch 153 and an LED indicator panel 152 . Pushbutton switch 153 may be utilized in conjunction with interface 151 to authenticate the tuner for use in the network and/or for initialization. A power supply unit 159 provides a supply voltage to the internal electronic components of the tuner.
[0075] Data from the satellite feed is received by a tuner 140 and output to decryption circuitry 141 , which may be configured to receive the latest encryption key information from a smart card 142 . The decrypted digital stream output from block 141 is then re-encrypted by encryption circuitry 143 prior to being sent locally to destination devices. As discussed above, the re-encryption is a type of encryption appropriate for the wireless network, not one that is locked into the satellite encryption scheme.
[0076] [0076]FIG. 14 is a circuit block diagram illustrating the basic architecture of a cable television tuner/router in accordance with one embodiment of the present invention. Practitioners in the art will appreciate that the architecture of FIG. 14 is somewhat more complicated due to the presence of both analog and digital signal channels. Elements 161 - 172 are basically the same as the corresponding components of the DBS tuner described above.
[0077] Tuner 175 receives the cable feed and separates the received signal into analog or digital channels, depending on whether the tuner is tuned to an analog or digital cable channel. If it is an analog channel, the video content is first decoded by block 177 and then compressed (e.g., MPEG2 or MPEG4) by circuit block 180 prior to downstream transmission. If it is a digital channel, a QAM demodulator circuit 176 is used to demodulate the received signal prior to decryption by block 178 . A point of deployment (POD) module 179 , which includes the decryption keys for the commercial cable system, is shown coupled to decryption block 178 . After decryption, the streaming media content is re-encrypted by block 181 before transmission downstream on the wireless network.
[0078] [0078]FIG. 14 shows a one-way cable system. As is well-known to persons of ordinary skill in the art, a two-way cable system further includes a modulator for communications back up the cable, as, for example, when a user orders a pay-per-view movie.
[0079] [0079]FIG. 15 is a circuit block diagram illustrating the basic architecture of a wireless receiver in accordance with one embodiment of the present invention. Like the repeater, DBS tuner, and cable tuner architectures described previously, the wireless receiver shown in FIG. 15 includes a CPU 185 , a RAM 186 , and a Flash ROM 187 coupled to a system bus 188 . A power supply unit 184 provides a supply voltage to each of the circuit elements shown.
[0080] A 5 GHz band upstream transceiver 189 is also shown in FIG. 15 coupled to an antenna 190 and to system bus 188 . A single transceiver is all that is required since the receiver of FIG. 23 does not transmit downstream (i.e., it is a leaf in the tree network) and it outputs directly to a display device such as a television. As described earlier, the 5 GHz band offers the advantage of more available channels. Accordingly, I/O ASIC circuitry 192 coupled to bus 188 includes the graphics, audio, decryption, and I/O chips (commercially available from manufacturers such as Broadcom Corporation and ATI Technologies, Inc.) needed to generate the output signals for driving the display device. Accordingly, in addition to elements 193 - 195 found on the repeater architecture of FIG. 11, I/O ASIC 192 may also provide outputs to a DVI connector 196 (for HDTV), analog audio/video (A/V) outputs 197 , an SP/DIF output 198 (an optical signal for surround sound and digital audio), and an infrared receiver port 199 for receiving commands from a remote control unit.
[0081] It should be understood that elements of the present invention may also be provided as a computer program product which may include a machine-readable medium having stored thereon instructions which may be used to program a computer (or other electronic device) to perform a process. The machine-readable medium may include, but is not limited to, floppy diskettes, optical disks, CD-ROMs, and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, magnet or optical cards, propagation media or other type of media/machine-readable medium suitable for storing electronic instructions. For example, elements of the present invention may be downloaded as a computer program product, wherein the program may be transferred from a remote computer (e.g., a server) to a requesting computer (e.g., a client) by way of data signals embodied in a carrier wave or other propagation medium via a communication link (e.g., a modem or network connection).
[0082] Furthermore, although the present invention has been described in conjunction with specific embodiments, numerous modifications and alterations are well within the scope of the present invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. | A wireless network includes a satellite antenna assembly with a reflector dish and at least one low-noise block converter (LNB) positioned opposite the reflector dish. A wireless transceiver transmits video and data information to one or more users located in a surrounding area. An interface unit is coupled to provide communication signals to the wireless transceiver. The unit is also configured for connection to an interactive data network so that the one or more users are provided with connectivity to the interactive data network via the wireless transceiver. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted With the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b). | Summarize the patent document, focusing on the invention's functionality and advantages. | [
"RELATED APPLICATIONS [0001] This application is a continuation-in-part application of Ser.",
"No. 10/315,624 filed Dec. 10, 2002 entitled, “WIRELESS NETWORK PROVIDING DISTRIBUTED VIDEO/DATA SERVICES.”",
"The present application is also related to Ser.",
"No.______ , filed Feb. 14, 2003.",
"FIELD OF THE INVENTION [0002] The present invention relates generally to the field of transmission of digital data;",
"more specifically, to satellite communication systems and networks for distributing video data and for providing interactive services to geographically dispersed clients.",
"BACKGROUND OF THE INVENTION [0003] Satellite communications systems have been widely deployed over the past several decades.",
"By way of example, Direct Broadcast Satellite (DBS) services have increasingly expanded to provide a variety of video program services directly to people's homes, apartments, and offices.",
"In a conventional direct-to-home (DTH) satellite communication system, one or more telecommunications satellites in geosynchronous orbit receive media content from a broadcast “uplink”",
"center.",
"The satellite then radiates microwave signal beams to send the media content across a geographical region of the planet.",
"For example, in the case of satellite service providers like DirectTV® video programs are broadcast across a wide region of the continental United States from several satellites in geosynchronous orbit above the Earth's equator.",
"[0004] Subscriber homes in the U.S. typically utilize an outdoor antenna dish mounted to their roof or an exterior wall to receive the satellite-transmitted signals.",
"A satellite receiver or set-top box within the home is connected to the antenna for acquiring the satellite carrier signal and displaying the video program content received from the satellite transmission.",
"As is well known, the satellite receiver may include decompression, decryption, decoder, demodulation and other circuitry for converting the received signals into a format (e.g., high definition television (HDTV), standard definition television (SDTV), etc.) suitable for viewing on a display device by the subscriber.",
"For example, for direct-to-home digital satellite carriers which conform to Digital Video Broadcast (DVB) standards, the satellite receiver is configured to receive a set of parameters that may include the polarization, symbol rate, forward error correcting (FEC) rate and frequency to acquire the satellite digital carrier.",
"U.S. Pat. Nos. 6,473,858, 6,430,233, 6,412,112, 6,323,909, 6,205,185, and 5,742,680 describe various conventional satellite communication systems that operate in this manner.",
"[0005] Satellite transmissions are often grouped in channel sets, wherein each channel set spans a certain transmit band.",
"The channel sets are typically isolated by different electromagnetic polarizations.",
"For instance, channel sets may be transmitted with linear polarization (i.e., horizontal or vertical) or circular polarization (i.e., left-hand or right-hand).",
"These channel sets are detected on a polarization-sensitive antenna assembly through a low-noise block converter (LNB) mounted opposite a parabolic antenna dish.",
"The LNB may be configured, for example, to detect the horizontal or vertical polarized signals reflected from the antenna dish.",
"The LNB connects to the satellite receiver unit or set-top box located inside the subscriber's home via a coaxial cable.",
"[0006] In some receiving systems two LNBs are provided to receive both channel sets so that multiple television sets within a home may view different program channels simultaneously.",
"Examples of different satellite data receiving systems are found in U.S. Pat. Nos. 6,424,817 and 5,959,592.",
"[0007] One of the problems with satellite communication systems is that they generally require an unobstructed line-of-sight between the orbiting satellite and the receiving antenna dish.",
"In the United States, for instance, satellites typically orbit above the equator and are therefore “seen”",
"by the antenna above the southern horizon.",
"A home in a densely populated metropolitan region, however, may have its view of the southern sky obstructed by a tall building.",
"In other cases, apartment dwellers living in units on the north side of a building may be precluded from mounting an antenna anywhere to receive satellite transmissions from a satellite orbiting above the southern horizon.",
"[0008] In other cases, landlords who own apartment buildings containing multiple units may be reluctant to permit tenants to mount multiple antenna dishes on their structure or route cable wires through the exterior and interior of the building.",
"Routing of wires is also a problem in homes, particularly when multiple televisions are to receive programming services.",
"The line-of-sight requirement and the problem of multi-dwelling units (MDUs) have therefore limited the number of homes that can receive digital services from satellite vendors.",
"[0009] An additional problem that satellite vendors generally face is the difficulty of providing interactive data services to their customers.",
"Some specialized satellite service providers offer two-way data services, but these systems require the subscriber to purchase a fairly large antenna dish (e.g., 3-5 feet wide) with increased power demands for uplink transmission to the satellite.",
"Another drawback is the inherent latency associated with signal transmission from Earth to the orbiting satellite, and then back down to Earth.",
"This latency can produce sluggish system performance as compared to terrestrial cable systems, for example, when the user wants to access a web page containing large amounts of content and data.",
"[0010] Thus, there is a pressing need for new apparatus and methods for distributing satellite services and video content to the general population on an expanded basis.",
"There is also a need for a communication network that provides additional services, such as interactive data services, to subscribers at a competitive cost and at a high performance level.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0011] The present invention will be understood more fully from the detailed description that follows and from the accompanying drawings, which however, should not be taken to limit the invention to the specific embodiments shown, but are for explanation and understanding only.",
"[0012] [0012 ]FIG. 1 is a conceptual diagram of a satellite communication system in accordance with one embodiment of the present invention.",
"[0013] [0013 ]FIG. 2 is a perspective view of an antenna assembly according to one embodiment of the present invention.",
"[0014] [0014 ]FIG. 3 is a more detailed view of the components comprising the signal unit of the antenna assembly shown in FIG. 2. [0015] [0015 ]FIG. 4 is an example showing an application of the present invention to a multi-dwelling unit.",
"[0016] [0016 ]FIG. 5 illustrates the spectrum band utilized for cable communications with the wireless transceiver in accordance with one embodiment of the present invention.",
"[0017] [0017 ]FIG. 6 depicts the type of information and signals transmitted between the network interface/satellite receiver device and antenna assembly according to one embodiment of the present invention.",
"[0018] [0018 ]FIG. 7 shows the example of FIG. 4 optionally including a mass storage repository according to another embodiment of the present invention.",
"[0019] [0019 ]FIG. 8 shows an alternative embodiment of the present invention, wherein a wireless transceiver is incorporated in a distribution box.",
"[0020] [0020 ]FIG. 9 shows an example of a wireless transceiver functioning as a free-standing repeater in accordance with an embodiment of the present invention.",
"[0021] [0021 ]FIG. 10 is an example of an antenna assembly according to another embodiment of the present invention.",
"[0022] [0022 ]FIG. 11 illustrates a wireless network that carries presentation layer content provided by a source to multiple destination devices in accordance with an embodiment of the present invention.",
"[0023] [0023 ]FIG. 12 illustrates a wireless network that seamlessly integrates Internet traffic with video content in accordance with an embodiment of the present invention.",
"[0024] [0024 ]FIG. 13 is a circuit block diagram of the basic architecture of a DBS tuner according to one embodiment of the present invention.",
"[0025] [0025 ]FIG. 14 is a circuit block diagram of the basic architecture of a cable television tuner/router in accordance with one embodiment of the present invention.",
"[0026] [0026 ]FIG. 15 is a circuit block diagram of the basic architecture of a wireless receiver in accordance with one embodiment of the present invention.",
"DETAILED DESCRIPTION [0027] The present invention is a pioneering advancement in the field of multimedia communication systems.",
"By integrating a wireless transceiver into a satellite antenna assembly, the present invention provides, for the first time, a wireless local area network (WLAN) which both distributes a wide range of video services (digitally-encoded broadcast services, pay-per-view television, and on-demand video services, etc.) and provides two-way (i.e., interactive) data services to individuals located across a wireless coverage region.",
"[0028] In the following description numerous specific details are set forth, such as frequencies, circuits, configurations, etc.",
", in order to provide a thorough understanding of the present invention.",
"However, persons having ordinary skill in the satellite and communication arts will appreciate that these specific details may not be needed to practice the present invention.",
"It should also be understood that the basic architecture and concepts disclosed can be extended to a variety of different implementations and applications.",
"Therefore, the following description should not be considered as limiting the scope of the invention.",
"[0029] With reference to FIG. 1, a conceptual diagram of a satellite communication system in accordance with the present invention is shown comprising a telecommunications satellite 12 positioned in a fixed, geosynchronous orbital location in the sky over the particular geographical region of the Earth.",
"Satellite 12 utilizes standard solar panels to generate power for the satellite's resources which includes one or more transponders that provide telecommunication links (i.e., “uplinks”",
"and “downlinks”) to Earth-based stations and receivers.",
"[0030] For example, FIG. 1 shows a large antenna 10 that broadcasts video programs from an uplink center to satellite 12 .",
"This uplink signal is represented by arrow 11 a. Satellite 12 transmits the broadcast signal (e.g., downlink 11 b ) across a coverage region of the Earth, where it may be received at a home 14 equipped with an outdoor antenna assembly coupled to electronics for displaying the video programs.",
"The antenna assembly, which is also shown in FIG. 2, includes a support 21 attached to a parabolic or concave reflector dish 16 , which is aimed to the location in the sky where satellite 12 is positioned in geosynchronous orbit above the earth.",
"Support 21 may include a base plate 13 to facilitate mounting of the antenna assembly to the exterior (e.g., roof) of house 14 .",
"An arm 15 , attached to either dish 16 or support 21 , extends to position a signal unit 18 at a focal point of the reflector dish 16 .",
"An antenna 77 for wireless transmissions is also shown attached to unit 18 .",
"Unit 18 converts the electromagnetic radiation reflected from dish 16 into electrical signals carried by one or more conductors 20 to a network interface unit 23 or satellite receiver 24 within home 14 .",
"Receiver 24 , for example, converts the satellite transmission signals into a format for display on television 26 .",
"[0031] With reference to FIG. 3, there is shown an exemplary embodiment of signal unit 18 in accordance with the present invention comprising a pair of low-noise block converters (LNBs) 72 &",
"73 and a wireless transceiver 71 mounted in a case or housing 76 .",
"Wireless transceiver 71 has an associated antenna 77 to effectuate wireless transmissions.",
"Feed horns 74 and 75 associated with LNBs 72 &",
"73 , respectively, protrude from a side of housing 76 that is positioned nearest to reflector dish 16 .",
"Alternatively, the signal unit 18 may utilize a single feed horn coupled to one or more LNBs.",
"Other embodiments may include multiple transceivers, each having its own associated wireless antenna.",
"For instance, an alternative embodiment may comprise a pair of LNBs with an associated pair of wireless transceivers, each having its own wireless antenna.",
"[0032] In this example, LNBs 72 &",
"73 may be configured to receive horizontally and vertically polarized satellite transmission signals.",
"Cable 20 connects with the LNBs and transceiver 71 .",
"(It should be understood that within the context of this disclosure, the term “cable”",
"is used to refer to one or more wires and that such wires may comprise coaxial wires of a type known as RG-6, or a similar type.) [0033] It is appreciated that in other embodiments unit 18 may comprise a single LNB and a wireless transceiver.",
"In still other embodiments, unit 18 may include four or more LNBs and one or more wireless transceivers mounted together.",
"[0034] [0034 ]FIG. 10 shows another exemplary embodiment of an antenna assembly in accordance with the present invention comprising side-by-side LNBs 172 &",
"173 mounted at the end of arm 115 attached to reflector dish 116 .",
"A pair of wireless transceivers (not shown) associated with LNBs 172 &",
"173 are coupled to antennas 177 &",
"178 , respectively affixed to LNBs 172 &",
"173 .",
"Feed horns 174 and 175 respectively attached to LNBs 172 &",
"173 are shown positioned to receive the satellite transmission signal reflected from dish 116 .",
"Support member 121 attaches to reflector dish 116 at one end, and to a bracket 122 at the opposite end.",
"Bracket 122 may include screw holes or other conventional means for mounting the antenna assembly to a permanent fixture of building, e.g., a wall, roof, etc.",
"Support member 21 and bracket 122 may also include adjustment apparatus for properly aiming reflector dish 116 at an orbiting broadcast satellite positioned at a certain point in the sky.",
"[0035] According to one embodiment of the present invention, wireless transceiver 71 operates in compliance with IEEE specification 802.11a, 802.11b, 802.11g, etc.",
", to provide high-speed networking and communication capability to computers, televisions, and other devices compatibly equipped to receive such wireless signals.",
"Other embodiments may operate in compliance with variant specifications that are compatible with IEEE specification 802.11a, 802.11b, or 802.11g, and which provide for wireless transmissions at high-bandwidth video data rates (e.g., about 2 Mbps or greater).",
"For the purposes of the present application, IEEE specification 802.11a, 802.11b, 802.11g, and Industrial, Scientific, and Medical (ISM) band networking protocols are denoted as “802.11x.”",
"Other non-ISM bands wireless network protocols could be utilized as well.",
"Transceiver 71 facilitates network connectivity to users located within a surrounding range, allowing them to receive satellite broadcast programs, pay-per-view services, on-demand video, Internet access, and other interactive data services, thus obviating the need for a wired connection to individual users.",
"[0036] In the example of FIG. 1, transceiver 71 operates over the license-free 5 GHz band (e.g., 5725 MHz to 5850 MHz) to provide upwards of 54 Mbps of bandwidth in good transmission conditions.",
"IEEE specification 802.11a allows for a high-speed wireless transmission of raw data at indoor distances of up to several hundred feet and outdoor distances of up to ten miles, depending on impediments, materials, and line-of-sight.",
"802.11a has twelve channels (eight in the low part of the band for indoor use and four in the upper for outdoor use) which do not overlap, allowing for dense installations.",
"According to the present invention, individual users may receive transmissions from transceiver 71 using hardware equipment available from a number of vendors.",
"For example, Proxim, Inc. manufactures and sells the Harmony 802.11a PCI card that provides wireless broadband networking at a data rate of 54 Mbps.",
"[0037] In another embodiment, transceiver 71 operates in compliance with IEEE specification 802.11g over the license-free 2.46 GHz band.",
"[0038] As shown in FIG. 1, wireless signals 17 may be transmitted from unit 18 of the antenna assembly mounted on house 14 to a nearby laptop computer 25 installed with a PC card or a PCI card that is 802.11x compliant.",
"Similar equipment may be installed into slots of a personal computer 38 or a television 37 to provide connectivity to network services in a house 36 that is located within the neighboring range of the wireless transceiver, despite the fact that house 36 does not have a satellite antenna dish or is not otherwise wired to receive such services.",
"This means, for example, that someone may access their electronic mail from any location within the full extent of the wireless network since the transmission signals pass easily through walls and glass.",
"[0039] In the example of FIG. 1, house 36 may be located outside of the signal range of wireless transmission signals 17 , but within the range of the wireless signals 27 from the transceiver mounted in unit 28 of antenna assembly 26 on top of a neighboring house 34 .",
"In such a case, the transceiver within unit 28 may function as a repeater or hub for house-to-house transmissions;",
"that is, to relay the media content and interactive services provided at home 14 to users at home 36 and elsewhere.",
"Through the use of transceivers 71 functioning as repeaters, content and two-way data services may be distributed to end users located at considerable distances from the original service connection source.",
"In other words, a neighborhood of antenna assemblies that include wireless transceivers can be used to create a network that provides distributed video program and interactive data connectivity.",
"Homes installed with an antenna assembly according to the present invention may still act as a house-to-house repeater for the neighborhood as part of a “roof-hopping”",
"scheme, even though they may not have an immediate need for wireless communications, Later on, those homes may simply add the appropriate hardware (e.g., wireless communication card, network interface box, etc.) to take advantage of the additional services such as interactive data provided by wireless connectivity.",
"[0040] It is appreciated that wireless transceiver 71 need not be physically located on or inside of signal unit 18 .",
"In FIG. 8, for example, a wireless transceiver connected to wireless antenna 111 is incorporated into a distribution box 110 .",
"Distribution box 110 may splice into cable 20 at any point, and therefore may be remotely located some distance from the antenna assembly comprising reflector 16 , arm 15 , and signal unit 18 .",
"In addition to providing a point for wireless transmissions, distribution box 110 may also function as a splitter or switching device for the signals carried on cable 20 .",
"[0041] It should be further understood that according to the present invention, the individual satellite antenna assemblies need not be located on homes or other buildings;",
"instead, they may be positioned on existing telephone poles, or mounted on other structures with dedicated, stand-alone hardware.",
"Additionally, a plurality of stand-alone wireless transceivers that function solely as signal repeaters may be distributed in a geographic region or throughout a large building wherever power is available to provide network connectivity that extends throughout the region or area.",
"[0042] For example, FIG. 9 shows a free-standing antenna assembly according to one embodiment of the present invention.",
"The antenna assembly, which includes a signal unit 18 with wireless antenna 77 positioned at the distal end of arm 15 opposite reflector 16 , is mounted on a pole 113 along with an associated solar cell panel 115 .",
"Solar cell panel 115 provides power to support the 802.11x wireless transceiver operating as a repeater on an around-the-clock basis.",
"Solar cell panel 115 may be dimensioned sufficiently large enough, and may be coupled to a storage cell battery (not shown) mounted on the pole or in back of the panel so as to provide power “24×7”",
"to the antenna assembly based on minimum daily solar radiation averages for the particular geographic location.",
"[0043] In an alternative embodiment, the concave or parabolic surface of reflector 16 may incorporate an array of solar cells.",
"For example, solar cells may cover a portion of the reflector surface to power the wireless transceiver(s) of the satellite antenna assembly, thus obviating the need for a separate solar cell panel.",
"In another implementation, the entire surface of the satellite dish reflector is covered with solar cells to provide power to the wireless transceiver or wireless satellite tuner.",
"[0044] [0044 ]FIG. 4 shows a large apartment building 50 with a satellite antenna assembly that includes a reflector dish 56 and a wireless transceiver mounted in signal unit 58 .",
"(The electronics that provides power and command/control signals for the antenna assembly is not shown in FIG. 4 for clarity reasons.) A series of repeaters 60 a - 60 e are located on various floors throughout the building to distribute signal transmissions to/from the transceiver of unit 58 to each of the multiple apartment units within building 50 .",
"A two-way data service connection (e.g., DSL) is provided to an 802.11x wireless transceiver/repeater 60 e. Thus, subscribers located anywhere within building 50 may connect to the DSL service via this wireless transmission.",
"Similarly, two-way data service connectivity is provided to others within the range of the transceiver of unit 58 of the antenna assembly mounted on the roof of building 50 (or to anyone in a neighboring region reached via roof-hopping signal repeating).",
"In a metropolitan region a single satellite antenna assembly with integrated wireless transceiver can therefore distribute high bandwidth services to residents of neighboring buildings, even though those neighboring buildings may not have a satellite antenna or be otherwise wired to receive those services.",
"[0045] Additionally, wireless transceiver/repeater 60 e may be connected to receive video content from some media source, e.g., a Digital Versatile Disk (“DVD”) player, or cable television programming.",
"In the later case, for instance, wireless transceiver/repeater 60 e may include a cable modem equipped with an 802.11x transmitter.",
"These alternative or additional services may then be distributed in a similar manner described above.",
"[0046] [0046 ]FIG. 1 also illustrates another extension of the network provided by the present invention, wherein media content may be distributed to an 802.11x compliant receiver unit 40 installed in the trunk of an automobile 39 , or other mobile vehicle.",
"Unit 40 , for instance, may include a hard disk drive to store video programs received from wireless transmission signals 17 when automobile 40 is parked, say, overnight in a garage.",
"These programs can then be viewed by rear-seat passengers on a trip the following day.",
"[0047] With continued reference to the example of FIG. 1, two-way data service is shown being provided by cable 19 connected to a network interface unit 23 .",
"Cable 19 may provide a direct subscriber line (DSL) connection, for instance, which may then be distributed to subscribers in the surrounding range of wireless signals 17 .",
"Thus, according to the present invention a user of laptop computer 25 , who may be located outdoors or at a nearby café, can access the Internet, watch a pay-per-view film, or receive a multitude of other multimedia services.",
"[0048] Alternatively, network interface unit 23 may be connected to a cable broadcast service provider (e.g., cable television) through an Ethernet or Universal Serial Bus (USB), or similar connection, thereby enabling wireless access of those cable services to subscribers within the range of the wireless network.",
"This means that a subscriber may watch their favorite television program or a pay-per-view movie from a laptop computer or television while outdoors, in a café, or in some other building, within the wireless coverage region without the need for a direct-wired cable connection.",
"Distribution of cable services may be implemented with a cable modem device that includes an 802.11x transmitter.",
"It is appreciated that additional circuitry for encrypting the video and data information may also be included to thwart pirates and interlopers.",
"[0049] Network interface unit 23 provides power to and communicates with transceiver 71 of unit 18 via cable 20 .",
"Although the embodiment of FIG. 1 shows network interface unit 23 connected to satellite receiver 24 , alternatively both devices may be integrated in to a single device 30 , as shown in FIG. 6. In either case, the network interface unit communicates with the transceiver using spectrum that is not otherwise utilized in cable 20 .",
"Since satellite receivers tend to operate in the spectrum from about 1.2 GHz to about 2 GHz, the spectrum below 1.2 GHz, down to about 40 MHz, may be used for communications with the wireless transceiver.",
"This spectrum band is illustrated in FIG. 5. [0050] It should also be understood that although FIG. 1 shows a direct connection between satellite receiver 24 and television 26 , alternatively, video services may be provided to any 802.11x compliant television (e.g., installed with an 802.11x adapter card) located within the house or surrounding wireless coverage region.",
"[0051] [0051 ]FIG. 6 depicts the type of information and signals carried by cable 20 between network interface/satellite receiver device 30 and unit 18 of the antenna assembly of the present invention.",
"Many techniques are well known in the electronics and communications arts for transmitting such signals, such as QPSK and QAM modulation.",
"As shown, satellite signals received by the antenna assembly are provided to device 30 via cable 20 .",
"Additionally, wireless transmissions received by transceiver 71 are coupled to device 30 .",
"Device 30 provides power to the LNBs and transceiver, LNB configurations signals, transceiver command and control signals, and wireless data via cable 20 .",
"By way of example, FIG. 6 shows device 30 having a DSL connection that may provide Internet access to users within the surrounding range of the transceiver of unit 18 .",
"[0052] [0052 ]FIG. 7 illustrates the MDU example of FIG. 4, but with a specialized mass storage repository unit 64 installed on the rooftop of building 50 .",
"Repository unit 64 comprises a number of hard disk drives (HDDs) having a large total storage capacity (e.g., 10 terabytes) arranged as a RAID (“Redundant Array of Inexpensive Disks”) 65 that functions as a media library apparatus.",
"An 802.11x compliant wireless transceiver 66 is also included in repository unit 64 along with various electronics 67 coupled to both RAID 65 and transceiver 66 .",
"Electronics 67 may comprise a microcomputer including a processor (CPU), a ROM, a RAM, etc.",
", to control the data read/write processing by the HDDs and to control the operation of transceiver 66 .",
"Electronics 67 may also include data compression/decompression circuitry for certain video and data applications.",
"Still other embodiments may include encryption/decryption circuitry for receiving and sending transmissions in a secure manner.",
"The RAID 65 , transceiver 66 , and electronics 67 are all housed in rugged, weather-resistant enclosure providing a suitable environment for the HDDs and the other circuitry.",
"[0053] Repository unit 64 may communicate via wireless transmission utilizing wireless transceiver 66 connected to a wireless antenna 68 mounted on top of unit 64 .",
"Alternatively, unit 64 may be coupled with signal unit 58 via a wire connection 69 (e.g., CAT-5) to utilize the transceiver in signal unit 58 for wireless communications.",
"[0054] In an alternative embodiment, repository unit 64 may be attached to the satellite antenna assembly to directly utilize the wireless transceiver installed in signal unit 58 .",
"[0055] The purpose of RAID 65 is to store recorded media content (e.g., pay-per-view movies, videos, DVDs, special event programs, etc.).",
"This content can be accumulated over time in a “trickle feed”",
"manner from wireless transceiver 66 , which may receive content from various sources such as satellite transmissions, media players, cable television, Internet, etc.",
"Over time, repository unit 64 may store such large volumes of video programming.",
"Anyone having the capability to access the wireless network can pay a fee to receive a particular show, movie, or viewable program stored in repository unit 64 on an on-demand basis.",
"[0056] Additionally, because of the interactive capabilities of the wireless network, the subscriber or user may communicate with unit 64 to provide commands such as “pause”, “fast forward”, “rewind”, etc.",
"Indeed, because of the large storage space available, live broadcast programs available through the WLAN described previously may be manipulated using such commands, thereby providing enhanced viewing flexibility to the user.",
"Hard disk drive failures, which often plague in-home digital video recorders (DVRs), are not a problem because of the redundancy protection built into the RAID.",
"Should a particular hard disk drive fail during operation, the remaining disk drive units simply take over until the repository unit can be serviced, at which time the failed drive can be replaced.",
"[0057] Repository unit 64 may also function as an archive storage apparatus for individuals within a local area to utilize as a storage facility for back-ups of personal data.",
"For example, personal data such as photographs, important documents, books, articles, etc.",
"may be transferred into a reserved space in the RAID 65 .",
"Various well-known security features may be built into repository unit 64 to maintain personal security of the backed-up data for each user.",
"[0058] It is also appreciated that repository unit 64 may be physically located somewhere other than on the rooftop of a building of MDUs.",
"For instance, instead of being attached to, or nearby, a rooftop antenna assembly, repository unit 64 may be located in a top floor space, in a basement, or in a ground level facility.",
"[0059] With reference now to FIG. 11, there is shown a wireless local area network (WLAN) having a topology comprising one or more access points or wireless repeaters that provides a wireless network transmission backbone 125 that carries data downstream to a variety of wireless destination devices located throughout a building, e.g., a home or office environment.",
"The access points or repeaters of wireless network backbone 125 may include 802.11x transceivers for transmitting data upstream from the destination devices to tuner 126 or the source broadband network (e.g., Internet).",
"The WLAN of FIG. 11 comprises a tuner 126 having a connection to a video/data source, such as cable television or satellite broadcast service provider.",
"Tuner 126 receives the content provided by the source and sends it across backbone 125 to one or more wireless destination devices, which may include, by way of example, a PDA 127 , laptop computer 130 , and a wireless receiver 128 coupled to SDTV/HDTV 129 .",
"In this example, PDA 127 and laptop computer 130 are each configured with wireless transceiver cards for receiving and transmitting data across the wireless network.",
"[0060] Practitioners in the art will further appreciate that tuner 126 may also digitize analog video, decode it, and compress the received source data prior to transmission across the wireless network, in addition to receiving compressed digital video.",
"In the case where compressed video is transmitted by tuner 126 , receiver 128 decompresses the data as it is received.",
"Alternatively, decompression circuitry may be incorporated into television 129 (or into an add-on box) that performs the same task.",
"Tuner 126 may include electronics for tuning the analog channels provided by a cable service provider as well as the digital channels provided by either cable or satellite service providers.",
"Tuner 126 may also include, or be adapted to receive, a smart card having decryption information for decrypting the satellite and/or cable signals received.",
"In other words, the wireless network of FIG. 11 may be configured to provide a media layer that includes encryption and entitlement information.",
"[0061] Alternatively, encryption/decryption key information may be stored within each of the destination devices.",
"For example, receiver 128 may include proprietary hardware/firmware or run software to exchange encryption key information or otherwise entitle receiver 128 to receive a proprietary signal.",
"Similarly laptop 130 may securely run software that will honor network entitlements.",
"As a subscriber to a particular satellite or cable service, a user may watch whatever content that may be received on their wireless receiver, laptop computer, PDA, etc.",
"That is, the entitlements may be securely transferred to any destination device owned by a subscriber.",
"Unlike conventional satellite or cable technologies in which the same encryption key is broadcast to everyone, in the embodiment of FIG. 11, the source provider transmits a unicast (i.e., point-to-point) transmission through a secure link with an encryption key specific to a particular receiver (or other destination device).",
"Individual encryption links are provided as opposed to an overall, universally-encrypted broadcast signal.",
"[0062] By way of further example, after decrypting the video/data content received from a satellite or cable service provider, tuner 126 may re-encrypt that content utilizing public key encryption before wirelessly transmitting the video/data from tuner 126 to receiver 128 across backbone 125 .",
"Re-encryption thwarts interlopers or unscrupulous hackers from stealing the signal.",
"Entitlement information, such as a list of authorized users or subscribers, may be specific to each receiver 128 .",
"In other words, tuner 126 may broadcast the encrypted cable video or satellite video signal across backbone 125 , but receiver 128 will have to be registered with the satellite or cable company, or be otherwise entitled, in order for the video content to be displayed on SDTV/HDTV 129 .",
"[0063] Still another possibility is for the cable or satellite company to grant an entitlement to tuner 126 that allows a certain limited number of data streams (e.g., three or four) to be transmitted in a particular household or office environment, regardless of the number of media destination devices that actually receive the media content.",
"This is simply another way to restrict distribution of the media content.",
"[0064] It should be understood that tuner 126 of FIG. 11 may be incorporated into the antenna assembly shown in any of the previous Figures.",
"That is, tuner 126 may be included in an antenna assembly mounted to the roof or side of a building.",
"In such configuration, the network of the present invention enables broadband video for the entire local area.",
"In other words, high bandwidth video content is introduced locally in the network.",
"Internet connection data can also be inserted locally via a connection to a T1, TS3, DSL, or other similar line.",
"Because satellite data is broadcast simultaneously across a wide geographic area, the present invention obviates the need to introduce video for each local area from the root of tree-like distribution network.",
"Instead, the video content for the network of the present invention can be inserted locally through satellite antenna assemblies, resulting in a very robust, ad hoc network.",
"[0065] Once tuner 126 has tuned (and possibly decrypted) the video/data content provided by the source, it functions as a wireless server to distribute that video/data content to authorized users connected to the wireless network.",
"In addition to video and data content, the wireless network shown in FIG. 11 may also carry presentation layer information to multiple destination devices.",
"This allows a network operator to define how they want the user interface presented with the transmitted content to be displayed.",
"For example, the network operator might permit a user to view movies with a certain set of presentation controls (e.g., pause, rewind, fast-forward, and so forth).",
"Another possibility is to include controls that allow a viewer to review a synopsis of the film, or information about the actors, much like the presentation layer sometimes used for DVDs.",
"In this manner, a DVD-like experience can be created at the front end of an entire cable or satellite network or system.",
"[0066] Presentation layer data may be loaded into receiver 128 , which would then download the video/data transmitted by tuner 126 across backbone 125 into an internal RAM, or Flash memory, and overlay the presentation layer information on top of the media content.",
"Thus, receiver 128 may take the various types of data it receives (video, audio, presentation, etc.) and reduce it to a particular format for display or reproduction.",
"The particular format may include the type of user interface presented when certain types of content are displayed.",
"[0067] Those of ordinary skill in the art will further appreciate that the wireless network of the present invention is client or destination device independent.",
"That is, it does not matter to the network what type of device is at the destination end receiving the transmitted media content.",
"Video and graphics content carried on the wireless local area network of the present invention can play on multiple types of television, computers (e.g., Macintosh® or PC), different MP3 players, PDAs, digital cameras, etc.",
"By way of example, any PC or Mac equipped with a 2.4 GHz band wireless transceiver card can detect the presence of the wireless network.",
"Once it has detected the running wireless network, it may download a driver that contains the necessary security and protocol information for accessing the media content.",
"Readily available software, such as RealPlayer®, QuickTime®, or Windows® MediaPlayer, may be used to play content provided through the network.",
"[0068] [0068 ]FIG. 12 illustrates a wireless network that seamlessly integrates Internet traffic with video content in accordance with another embodiment of the present invention.",
"In addition to the devices shown in FIG. 11, the WLAN of FIG. 12 further includes a cable/DSL wireless router 133 and wireless disk server 131 coupled to backbone 125 .",
"Router 133 transmits data from a conventional cable or DSL data network across backbone 125 to the various destination devices located within the range of the WLAN.",
"Data may also be transmitted back to the cable/DSL network from each of the destination devices via backbone 125 and router 133 .",
"The cable/DSL data integrates seamlessly with the wireless data stream so that, for example, one user may download data from the Internet while another user watches a movie or television program.",
"In other words, tuner 126 and router 133 share the same spectrum.",
"[0069] Wireless disk server 131 comprises one or more disk drive units that function as a file server controlled by a microcontroller or other controller unit that may include a 802.11x transceiver, a RAM, ROM, CPU, Flash memory and other electronic devices for receiving data transmitted across backbone 125 and storing that data on a magnetic or magneto-optical recording media.",
"Disk server 131 also functions to retrieve data previously stored for transmission on the wireless network to other requesting devices, such as laptop computer 130 .",
"[0070] Disk server 131 provides archival storage of video and other data for the wireless local area network, and also facilitates certain presentation layer features, such as digital video recording (DVR) capabilities.",
"For instance, video data may be stored on a magnetic disk media in server 131 for later on-demand viewing with full playback, pause, rewind, fast-forward, etc.",
", command features.",
"Essentially, disk server functions as a mass repository unit in the same manner as repository unit 64 previously described in conjunction with FIG. 7. Disk server 131 , however, need not be a secure device.",
"The reason why is because the WLAN shown in FIG. 12 writes/reads data to the disk storage of server 131 in encrypted form.",
"This data can only be decrypted by a device having the proper entitlements.",
"In other words, the same entitlements that allow a user or subscriber to watch a movie broadcast by a service provider such as the Dish® network, allow that same user to watch a previously recorded movie (stored to disk server 131 ) received from a Dish® transmission.",
"Put another way, disk server 131 does not need encryption/decryption capabilities, and may comprise an ordinary disk server configured for wireless communications.",
"[0071] By that same token, any computer that is within the transmission range of the wireless network of the present invention can use that computer's internal disk drive for storage of video/data.",
"Note that the archived video/data may be unusable without the proper entitlements;",
"that is, to be able to play back a stored video program a user would need a subscription to the broadcast service, or other appropriate entitlement.",
"[0072] With reference now to FIG. 13, a circuit block diagram showing the architecture of a DBS tuner according to one embodiment of the present invention is shown including a CPU 144 , a RAM 145 , a Flash ROM 146 , and I/O ASIC 147 coupled to a system bus 155 .",
"Also coupled to system bus 155 are a plurality of transceivers, which, in this particular embodiment, include a 5 GHz downstream transceiver 156 , and a 2.4 GHz transceiver 157 , both of which are coupled to an antenna 160 .",
"(An upstream transceiver is not needed at the source end.) Additional transceivers operating at different frequencies may also be included.",
"In this implementation, transceiver 156 operates in compliance with IEEE specification 802.11a to run with an effective throughput of 36 Mbps for transmissions on backbone 125 .",
"Transceiver 157 is 802.11g-compliant and also runs with an effective throughput of 36 Mbps to connect to any local devices operating in the 2.4 GHz band.",
"[0073] CPU 144 controls the transmission of the data packets, utilizing RAM 145 for both program execution, and for buffering of the packets as they are received from the source feed before they are sent out to the downstream side, i.e., toward the destination.",
"Flash ROM 146 may be used to hold software and encryption key information associated with secure transmissions, for example, to insure that the network users are authorized users of satellite or cable subscriber services.",
"[0074] In the embodiment of FIG. 13, a 1394 connector interface 151 provides a Firewire® port (coupled through a 1394 PHY physical interface) to I/O ASIC 147 .",
"Also coupled to I/O ASIC 66 is a pushbutton switch 153 and an LED indicator panel 152 .",
"Pushbutton switch 153 may be utilized in conjunction with interface 151 to authenticate the tuner for use in the network and/or for initialization.",
"A power supply unit 159 provides a supply voltage to the internal electronic components of the tuner.",
"[0075] Data from the satellite feed is received by a tuner 140 and output to decryption circuitry 141 , which may be configured to receive the latest encryption key information from a smart card 142 .",
"The decrypted digital stream output from block 141 is then re-encrypted by encryption circuitry 143 prior to being sent locally to destination devices.",
"As discussed above, the re-encryption is a type of encryption appropriate for the wireless network, not one that is locked into the satellite encryption scheme.",
"[0076] [0076 ]FIG. 14 is a circuit block diagram illustrating the basic architecture of a cable television tuner/router in accordance with one embodiment of the present invention.",
"Practitioners in the art will appreciate that the architecture of FIG. 14 is somewhat more complicated due to the presence of both analog and digital signal channels.",
"Elements 161 - 172 are basically the same as the corresponding components of the DBS tuner described above.",
"[0077] Tuner 175 receives the cable feed and separates the received signal into analog or digital channels, depending on whether the tuner is tuned to an analog or digital cable channel.",
"If it is an analog channel, the video content is first decoded by block 177 and then compressed (e.g., MPEG2 or MPEG4) by circuit block 180 prior to downstream transmission.",
"If it is a digital channel, a QAM demodulator circuit 176 is used to demodulate the received signal prior to decryption by block 178 .",
"A point of deployment (POD) module 179 , which includes the decryption keys for the commercial cable system, is shown coupled to decryption block 178 .",
"After decryption, the streaming media content is re-encrypted by block 181 before transmission downstream on the wireless network.",
"[0078] [0078 ]FIG. 14 shows a one-way cable system.",
"As is well-known to persons of ordinary skill in the art, a two-way cable system further includes a modulator for communications back up the cable, as, for example, when a user orders a pay-per-view movie.",
"[0079] [0079 ]FIG. 15 is a circuit block diagram illustrating the basic architecture of a wireless receiver in accordance with one embodiment of the present invention.",
"Like the repeater, DBS tuner, and cable tuner architectures described previously, the wireless receiver shown in FIG. 15 includes a CPU 185 , a RAM 186 , and a Flash ROM 187 coupled to a system bus 188 .",
"A power supply unit 184 provides a supply voltage to each of the circuit elements shown.",
"[0080] A 5 GHz band upstream transceiver 189 is also shown in FIG. 15 coupled to an antenna 190 and to system bus 188 .",
"A single transceiver is all that is required since the receiver of FIG. 23 does not transmit downstream (i.e., it is a leaf in the tree network) and it outputs directly to a display device such as a television.",
"As described earlier, the 5 GHz band offers the advantage of more available channels.",
"Accordingly, I/O ASIC circuitry 192 coupled to bus 188 includes the graphics, audio, decryption, and I/O chips (commercially available from manufacturers such as Broadcom Corporation and ATI Technologies, Inc.) needed to generate the output signals for driving the display device.",
"Accordingly, in addition to elements 193 - 195 found on the repeater architecture of FIG. 11, I/O ASIC 192 may also provide outputs to a DVI connector 196 (for HDTV), analog audio/video (A/V) outputs 197 , an SP/DIF output 198 (an optical signal for surround sound and digital audio), and an infrared receiver port 199 for receiving commands from a remote control unit.",
"[0081] It should be understood that elements of the present invention may also be provided as a computer program product which may include a machine-readable medium having stored thereon instructions which may be used to program a computer (or other electronic device) to perform a process.",
"The machine-readable medium may include, but is not limited to, floppy diskettes, optical disks, CD-ROMs, and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, magnet or optical cards, propagation media or other type of media/machine-readable medium suitable for storing electronic instructions.",
"For example, elements of the present invention may be downloaded as a computer program product, wherein the program may be transferred from a remote computer (e.g., a server) to a requesting computer (e.g., a client) by way of data signals embodied in a carrier wave or other propagation medium via a communication link (e.g., a modem or network connection).",
"[0082] Furthermore, although the present invention has been described in conjunction with specific embodiments, numerous modifications and alterations are well within the scope of the present invention.",
"Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense."
] |
[0001] A method and an apparatus are proposed for adaptive cruise control of a motor vehicle along the lines of a distance-constant control and a speed-constant control, respectively, which includes at least two devices interconnected by a data-exchange device. The first device has at least one transmitting and receiving unit for detecting objects, which operates according to the radar principle and/or lidar principle, as well as at least one target-object selection device. The second device has at least one speed and distance controller, and is connected to the first device by a data-exchange system through which data with respect to two detected objects is transmitted.
BACKGROUND INFORMATION
[0002] From the publication “Adaptive Cruise Control System Aspects and Development Trends” by Winner, Witte et al., released at the SAE International Congress & Exposition, Detroit, Feb. 26-29, 1996, an adaptive cruise controller is known which detects preceding vehicles by radar radiation and undertakes a distance control or speed control as a function of the detected objects. From this publication, it is known to construct such a unit so that the radar device, the target-object selection, as well as the distance and speed controller are accommodated in a shared housing.
[0003] From the publication “Auf eigene Verantwortung” (On One's Own Responsibility) by E. Kittler, published in the periodical mot 2/2000, pp. 74 through 76, an autonomous intelligent cruise controller is known in which the distance sensor, operating on the basis of radar, as well as the control unit for the distance and speed control are provided separately in a vehicle.
ESSENCE AND ADVANTAGES OF THE INVENTION
[0004] The essence of the present invention is a system for adaptive cruise control of a motor vehicle along the lines of a distance-constant control and a speed-constant control, respectively, which is made of two devices interconnected by a data-exchange device. The first device includes at least one object-detection device as well as at least one target-object selection device. The object-detection device is able to detect further vehicles and objects in the vicinity of one's own vehicle, and to measure their characteristic, kinematic variables. In the target-object selection device of the first device, two objects are selected from the detected objects, and the characteristic, kinematic variables of these two selected objects are forwarded for further processing to a second device which includes at least one distance and speed controller. From the characteristic, kinematic variables of the two selected, detected objects, this distance and speed controller generates output signals by which a power-regulating control element of an internal combustion engine or an actuator of the deceleration means may be controlled. Due to the selection of exactly two objects by the target-object selection device and the transmission of the associated characteristic, kinematic variables to the distance and speed controller, the amount of data between the first device and the second device is kept small. Known systems either transmit all detected object data between the first device and the second device, which may result in a very great abundance of transmitted data, although a large part of the detected objects is irrelevant for the instantaneous distance and speed control. Other known systems select precisely one object from the detected objects, whose characteristic, kinematic variables are used for the distance and speed control. Particularly in traffic situations in which the selected target object leaves one's own lane or in which a further vehicle slips in between one's own vehicle and the preceding target object, this leads to unwanted control reactions which may express themselves, for example, by bucking, jerky giving of gas, jerky taking away of gas or jerky response of the deceleration means. By transmitting the characteristic, kinematic variables of precisely two objects, it is possible to transmit the variables of a further object in addition to the variables of the selected target object. In so doing, the kinematic variables of the object classified as a potential future target object are transmitted in particular. The distance and speed controller is thereby already able to adjust early to the new situation which comes about, for example, by a vehicle slipping in, or the target object changing lanes. The control response of a vehicle controlled in this manner thereby improves noticeably because of gentle transitions in response to strongly changing control situations.
[0005] It is also an object of the present invention to indicate an apparatus that includes at least one device for detecting objects, one device for target-object selection and one device for transmitting data. In this context, the device for object detection detects the vehicles and objects located in the surrounding region of one's own vehicle. Moreover, this object-detection device is able to acquire characteristic, kinematic variables of the vehicles, among these variables also being those which are of special interest for a cruise control along the lines of a distance-constant control or speed-constant control. From the detected objects, the device provided for target-object selection selects the target object which is of special interest for the control and which determines the instantaneous control response. Moreover, the device for target-object selection selects a further object which could be selected as the new target object in the further course, and therefore influences the control activity. The additionally provided device for transmitting data routes the characteristic, kinematic variables of the selected objects to the control device.
[0006] Another object of the present invention is an apparatus for controlling the traveling speed along the lines of a speed-constant control or distance-constant control, which has at least one distance and speed controller, a data-exchange device, as well as output devices for relaying output signals. According to the present invention, with the aid of the data-exchange device, this apparatus receives characteristic, kinematic variables of precisely two objects which were detected by an object-detection system, and supplies the variables to the distance and speed controller provided. Having regard for the characteristic, kinematic variables, the distance and speed controller in turn generates output signals by which at least one power-regulating control element of an internal combustion engine and/or a device for actuating the deceleration means may be controlled.
[0007] A further object of the present invention is an apparatus for the exchange of signals between a first device and a second device, the characteristic, kinematic variables of precisely two detected objects being transmitted by the apparatus of the present invention. The first device includes at least one object-detection unit and at least one device for target-object selection, and the second device includes at least one speed and distance controller.
[0008] The present invention also provides a method for the exchange of signals between a first device and a second device, the first device having at least one object-detection system and a device for the target-object selection, and the second device having at least one speed and distance controller. The essence of the method is to forward the characteristic, kinematic variables, acquired by the object-detection system, of precisely the two objects which were selected by the target-object selection device, to the second device in which control signals are provided (generated) for a power-regulating final controlling element of an internal combustion engine and for a triggering of the deceleration means.
[0009] According to the present invention, this is achieved by the features of the independent claims. Advantageous further developments and refinements are derived from the dependent claims.
[0010] The object-detection device is advantageously a transmitting and receiving unit for radar radiation and/or a transmitting and receiving unit for lidar radiation and/or a receiving unit for an image sensing system. In this connection, the radar method according to which the transmitting and receiving unit for radar radiation operates and the ranges for which it is designed are unimportant. In principle, this system is able to operate with any radar modulation or any radar range. The image sensing system provided is advantageously a video camera, which may also be a stereo video camera, and which is able to receive image information in the visible or even in the infrared light spectrum. It is also possible to furnish the provided image sensing system with a lighting device which illuminates the desired sensing range with visible or even infrared light, in order to improve the image sensing properties.
[0011] Moreover, it is advantageous that the characteristic, kinematic variables, which correspond to the transmitted data, are at least one of the following variables: distance of the object to the object-detection device, relative velocity of the object in relation to one's own vehicle velocity or absolute velocity of the object, relative acceleration of the object with respect to one's own vehicle or absolute acceleration of the object, sway of the object relative to the vehicle longitudinal axis or relative to the center axis of the object-detection device, lateral velocity of the object relative to the vehicle longitudinal axis or the center axis of the object detection system, a clear-cut object designation, information about whether the object was detected for the first time or was already detected repeatedly, information about the performance reliability of the object-detection device, for example, whether it is exactly adjusted, whether it is soiled, whether it is blinded at the moment, or whether visibility is poor.
[0012] It is also advantageous that the first device and the second device are accommodated in a shared housing. In providing a shared housing for the first and the second device, it is advantageous that one gets along with a single unit, and does not have to accommodate two units at different places in the vehicle and connect them.
[0013] It is also advantageous if the first device and the second device are accommodated in two separate housings. The spatial separation of the first device and the second device in separate housings makes it possible to provide a sensor which is very small with respect to the construction size, and therefore is very versatile in its usage. In this case, the second housing is to be provided at a distant location at which sufficient space is available.
[0014] The apparatus for the exchange of signals between the first device and the second device is advantageously a CAN bus.
[0015] Implementation of the method according to the present invention in the form of a control element, which is provided for a control unit of an adaptive distance control and speed control of a motor vehicle, is especially important. In this context, a program capable of running on a computer, in particular on a microprocessor, and suitable for executing the method according to the present invention, is stored on the control element. Thus, in this case, the present invention is implemented by a program stored on the control element, so that this control element provided with the program constitutes the present invention in the same manner as the method for whose execution the program is suitable. An electric storage medium such as a read-only memory may be used in particular as the control element.
[0016] Further features, uses and advantages of the present invention come to light from the following description of exemplary embodiments of the invention which are shown in the figures of the Drawing. All the features described or illustrated here, either alone or in any desired combination, constitute the object of the present invention, regardless of their combination in the patent claims or their antecedent, and regardless of how they are formulated in the description or illustrated in the Drawing.
BRIEF DESCRIPTION OF THE DRAWING
[0017] In the following, exemplary embodiments of the present invention are explained with reference to the Drawing, in which:
[0018] [0018]FIG. 1 shows an illustrative surroundings situation for the use of an adaptive distance and speed control;
[0019] [0019]FIG. 2 shows a first exemplary embodiment of the apparatus according to the present invention; and
[0020] [0020]FIG. 3 shows a further exemplary embodiment of the apparatus according to the present invention.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0021] [0021]FIG. 1 shows an exemplary traffic situation for the use of an adaptive distance and speed controller. One can see vehicle 1 , equipped with adaptive distance and speed controller 2 , which is moving, for example, in the center lane of a multi-lane road. Object detection system 2 , which may be implemented as a radar system, lidar system or video system and which is customarily mounted on the front side of vehicle 1 , detects the further objects in the surrounding field of the vehicle which are located within the sensing range whose limits are indicated by the two lines 4 . Center axis 3 of the object sensing range is also drawn in, which, in the case of a radar device or lidar device, coincides with the principal beam direction of the transmitting and receiving devices. A target-object selection device selects a suitable target object 5 from the objects detected by object sensing system 2 . This target object is usually vehicle 5 directly in front of one's own vehicle, whose behavior from the standpoint of operating dynamics dominantly influences the control response of one's own vehicle 1 . Further objects 6 are recognized only if they are moving within sensing range 4 . The operating-dynamics variables of these further objects 6 achieve relevance in the case when this further object intends it, for example, by a planned cut-in maneuver between one's own vehicle 1 and preceding vehicle 5 , or when target-object vehicle 5 falls out, for example, due to a lane change, and a further preceding vehicle 6 is identified as the new target object. Thus, the operating-dynamics variables of current target object 5 , as well as the operating-dynamics variables of a further detected object 6 which was recognized as a potential future target object, are relevant for the instantaneous and the future control response of vehicle 1 .
[0022] A first exemplary embodiment of the apparatuses according to the present invention is shown in FIG. 2. One can see a first device 7 , which, according to the present invention, has at least one object-detection device as well as a target-object selection device. In the event the object-detection system is a radar system or lidar system, this first device 7 is provided with a transmitting and receiving device 8 . In the case of an object-detection system in the form of an image sensing device, receiving element 8 represents a pure receiving system that, for example, may take the form of a video camera. Transmitting and receiving device 8 sends out radar signals or lidar signals which, in the case of a preceding vehicle, are reflected at this object 5 , 6 and are reflected back to the transmitting and receiving device. The object-detection device is able to acquire operating-dynamics variables such as the distance of object 9 , the absolute velocity or relative velocity of object 9 in relation to transmitting and receiving device 8 , the absolute acceleration or relative acceleration of object 9 in relation to the object-detection system, the lateral velocity of object 9 relative to the vehicle longitudinal axis or object-detection center axis 3 , and to provide information about whether the object-detection system is exactly adjusted, is soiled, is blinded, or whether visibility is poor. From detected objects 9 , the target-object selection device, further provided in first device 7 , selects the target object whose operating-dynamics variables have a dominant effect on the distance and speed controller. The target-object selection device also selects a further detected object, which was identified as a potential future target object. In so doing, objects 9 are considered in particular which slip in between one's own vehicle 1 and target object 5 , or objects 6 preceding target object 5 are considered for the case when target object 5 falls out of the current traffic lane and is no longer suitable as a target object. The characteristic, kinematic or operating-dynamics variables of these two objects, selected by the target-object selection device, are routed via a device for data exchange 13 to a second device 10 . This second device 10 has at least one speed and distance controller. In the case when no preceding object was detected, this distance and speed controller functions as a constant-speed controller, and in the case when at least one preceding object 5 was detected, functions as a constant-distance controller. To that end, the operating-dynamics variables transmitted by data-exchange device 13 are routed to the distance and speed controller which generates two output signals that influence the performance. These two output signals are, in particular, an output variable for controlling a power-regulating control element 11 for an internal combustion engine, particularly an electrically actuated throttle valve or an electrically controlled injection system, as well as a control signal for triggering deceleration means 12 of vehicle 1 . Because first device 7 transmits only the operating-dynamics variables of two detected objects to second device 10 via data-exchange device 13 , the amount of data between first device 7 and second device 10 is kept small in comparison to systems which transmit operating-dynamics variables with respect to all detected objects. Compared to systems which transmit only the operating-dynamics variables of target object 5 , a better control response results, particularly in driving situations in which target object 5 is changed, since the operating-dynamics variables of the potential new target object are already available prior to the target-object change of the distance and speed controller. The modular design of this adaptive speed and distance controller makes it possible to provide first device 7 and second device 10 in separate housings, which means the first device, in a small type of construction, may be mounted on the front of the vehicle, and second device 10 may be installed at a convenient place at another location in the vehicle.
[0023] [0023]FIG. 3 shows a further specific embodiment of the apparatuses according to the present invention. Again, one is able to see first device 7 , which has at least one object-detection device as well as a target-object selection device. Through transmitting and receiving element 8 , which, in the case of an image recognition system, may also be implemented as a pure receiving element, radar or lidar beams are sent out which are reflected at a preceding object 9 and are received by receiving element 8 . From the detected objects, the target-object selection device selects a target object which dominantly influences the controller response of the distance and speed controller, as well as a further, potential, future target object. The operating-dynamics variables of these two selected objects are routed to second device 10 by data-exchange device 13 . In this second device 10 , which has at least one distance and speed controller, from the transmitted, operating-dynamics variables of the two selected objects, first of all an output signal for a power-regulating control element 11 of an internal combustion engine is generated, and furthermore, an output signal is generated for controlling deceleration means 12 of the vehicle. It is also within the meaning of the present invention that first device 7 and second device 10 are accommodated in a shared housing 14 , so that data-exchange device 13 represents an internal interface between two modules 7 , 10 . This modular design of the adaptive speed and distance controller makes it possible to provide a standardized first device, as well as a likewise standardized second device 10 , which may be interconnected depending upon the use of this distance and speed controller.
[0024] It is also conceivable to provide two first devices 7 that transmit data via data-exchange devices 13 to a second device 10 in common, thereby permitting a very universal utilization of this system. By the transmission of the operating-dynamics variables of two objects, the distance and speed controller, provided in second device 10 , is independent of the selection criteria of the target-object selection device in first device 7 , which means an improved control function is achieved in complex traffic situations. The modular design furthermore permits better interchangeability of the object-detection system and of the control unit which acts directly on actuators 11 , 12 . | A method and an apparatus are proposed for the adaptive cruise control of a motor vehicle along the lines of a distance-constant control and a speed-constant control, respectively, which includes at least two devices interconnected by a data-exchange device. The first device has at least one transmitting and receiving unit for detecting objects, which operates according to the radar principle and/or lidar principle, as well as at least one target-object-selection device. The second device has at least one speed and distance controller, and is connected to the first device by a data-exchange system through which data with respect to two detected objects is transmitted. | Identify the most important aspect in the document and summarize the concept accordingly. | [
"[0001] A method and an apparatus are proposed for adaptive cruise control of a motor vehicle along the lines of a distance-constant control and a speed-constant control, respectively, which includes at least two devices interconnected by a data-exchange device.",
"The first device has at least one transmitting and receiving unit for detecting objects, which operates according to the radar principle and/or lidar principle, as well as at least one target-object selection device.",
"The second device has at least one speed and distance controller, and is connected to the first device by a data-exchange system through which data with respect to two detected objects is transmitted.",
"BACKGROUND INFORMATION [0002] From the publication “Adaptive Cruise Control System Aspects and Development Trends”",
"by Winner, Witte et al.",
", released at the SAE International Congress &",
"Exposition, Detroit, Feb. 26-29, 1996, an adaptive cruise controller is known which detects preceding vehicles by radar radiation and undertakes a distance control or speed control as a function of the detected objects.",
"From this publication, it is known to construct such a unit so that the radar device, the target-object selection, as well as the distance and speed controller are accommodated in a shared housing.",
"[0003] From the publication “Auf eigene Verantwortung”",
"(On One's Own Responsibility) by E. Kittler, published in the periodical mot 2/2000, pp. 74 through 76, an autonomous intelligent cruise controller is known in which the distance sensor, operating on the basis of radar, as well as the control unit for the distance and speed control are provided separately in a vehicle.",
"ESSENCE AND ADVANTAGES OF THE INVENTION [0004] The essence of the present invention is a system for adaptive cruise control of a motor vehicle along the lines of a distance-constant control and a speed-constant control, respectively, which is made of two devices interconnected by a data-exchange device.",
"The first device includes at least one object-detection device as well as at least one target-object selection device.",
"The object-detection device is able to detect further vehicles and objects in the vicinity of one's own vehicle, and to measure their characteristic, kinematic variables.",
"In the target-object selection device of the first device, two objects are selected from the detected objects, and the characteristic, kinematic variables of these two selected objects are forwarded for further processing to a second device which includes at least one distance and speed controller.",
"From the characteristic, kinematic variables of the two selected, detected objects, this distance and speed controller generates output signals by which a power-regulating control element of an internal combustion engine or an actuator of the deceleration means may be controlled.",
"Due to the selection of exactly two objects by the target-object selection device and the transmission of the associated characteristic, kinematic variables to the distance and speed controller, the amount of data between the first device and the second device is kept small.",
"Known systems either transmit all detected object data between the first device and the second device, which may result in a very great abundance of transmitted data, although a large part of the detected objects is irrelevant for the instantaneous distance and speed control.",
"Other known systems select precisely one object from the detected objects, whose characteristic, kinematic variables are used for the distance and speed control.",
"Particularly in traffic situations in which the selected target object leaves one's own lane or in which a further vehicle slips in between one's own vehicle and the preceding target object, this leads to unwanted control reactions which may express themselves, for example, by bucking, jerky giving of gas, jerky taking away of gas or jerky response of the deceleration means.",
"By transmitting the characteristic, kinematic variables of precisely two objects, it is possible to transmit the variables of a further object in addition to the variables of the selected target object.",
"In so doing, the kinematic variables of the object classified as a potential future target object are transmitted in particular.",
"The distance and speed controller is thereby already able to adjust early to the new situation which comes about, for example, by a vehicle slipping in, or the target object changing lanes.",
"The control response of a vehicle controlled in this manner thereby improves noticeably because of gentle transitions in response to strongly changing control situations.",
"[0005] It is also an object of the present invention to indicate an apparatus that includes at least one device for detecting objects, one device for target-object selection and one device for transmitting data.",
"In this context, the device for object detection detects the vehicles and objects located in the surrounding region of one's own vehicle.",
"Moreover, this object-detection device is able to acquire characteristic, kinematic variables of the vehicles, among these variables also being those which are of special interest for a cruise control along the lines of a distance-constant control or speed-constant control.",
"From the detected objects, the device provided for target-object selection selects the target object which is of special interest for the control and which determines the instantaneous control response.",
"Moreover, the device for target-object selection selects a further object which could be selected as the new target object in the further course, and therefore influences the control activity.",
"The additionally provided device for transmitting data routes the characteristic, kinematic variables of the selected objects to the control device.",
"[0006] Another object of the present invention is an apparatus for controlling the traveling speed along the lines of a speed-constant control or distance-constant control, which has at least one distance and speed controller, a data-exchange device, as well as output devices for relaying output signals.",
"According to the present invention, with the aid of the data-exchange device, this apparatus receives characteristic, kinematic variables of precisely two objects which were detected by an object-detection system, and supplies the variables to the distance and speed controller provided.",
"Having regard for the characteristic, kinematic variables, the distance and speed controller in turn generates output signals by which at least one power-regulating control element of an internal combustion engine and/or a device for actuating the deceleration means may be controlled.",
"[0007] A further object of the present invention is an apparatus for the exchange of signals between a first device and a second device, the characteristic, kinematic variables of precisely two detected objects being transmitted by the apparatus of the present invention.",
"The first device includes at least one object-detection unit and at least one device for target-object selection, and the second device includes at least one speed and distance controller.",
"[0008] The present invention also provides a method for the exchange of signals between a first device and a second device, the first device having at least one object-detection system and a device for the target-object selection, and the second device having at least one speed and distance controller.",
"The essence of the method is to forward the characteristic, kinematic variables, acquired by the object-detection system, of precisely the two objects which were selected by the target-object selection device, to the second device in which control signals are provided (generated) for a power-regulating final controlling element of an internal combustion engine and for a triggering of the deceleration means.",
"[0009] According to the present invention, this is achieved by the features of the independent claims.",
"Advantageous further developments and refinements are derived from the dependent claims.",
"[0010] The object-detection device is advantageously a transmitting and receiving unit for radar radiation and/or a transmitting and receiving unit for lidar radiation and/or a receiving unit for an image sensing system.",
"In this connection, the radar method according to which the transmitting and receiving unit for radar radiation operates and the ranges for which it is designed are unimportant.",
"In principle, this system is able to operate with any radar modulation or any radar range.",
"The image sensing system provided is advantageously a video camera, which may also be a stereo video camera, and which is able to receive image information in the visible or even in the infrared light spectrum.",
"It is also possible to furnish the provided image sensing system with a lighting device which illuminates the desired sensing range with visible or even infrared light, in order to improve the image sensing properties.",
"[0011] Moreover, it is advantageous that the characteristic, kinematic variables, which correspond to the transmitted data, are at least one of the following variables: distance of the object to the object-detection device, relative velocity of the object in relation to one's own vehicle velocity or absolute velocity of the object, relative acceleration of the object with respect to one's own vehicle or absolute acceleration of the object, sway of the object relative to the vehicle longitudinal axis or relative to the center axis of the object-detection device, lateral velocity of the object relative to the vehicle longitudinal axis or the center axis of the object detection system, a clear-cut object designation, information about whether the object was detected for the first time or was already detected repeatedly, information about the performance reliability of the object-detection device, for example, whether it is exactly adjusted, whether it is soiled, whether it is blinded at the moment, or whether visibility is poor.",
"[0012] It is also advantageous that the first device and the second device are accommodated in a shared housing.",
"In providing a shared housing for the first and the second device, it is advantageous that one gets along with a single unit, and does not have to accommodate two units at different places in the vehicle and connect them.",
"[0013] It is also advantageous if the first device and the second device are accommodated in two separate housings.",
"The spatial separation of the first device and the second device in separate housings makes it possible to provide a sensor which is very small with respect to the construction size, and therefore is very versatile in its usage.",
"In this case, the second housing is to be provided at a distant location at which sufficient space is available.",
"[0014] The apparatus for the exchange of signals between the first device and the second device is advantageously a CAN bus.",
"[0015] Implementation of the method according to the present invention in the form of a control element, which is provided for a control unit of an adaptive distance control and speed control of a motor vehicle, is especially important.",
"In this context, a program capable of running on a computer, in particular on a microprocessor, and suitable for executing the method according to the present invention, is stored on the control element.",
"Thus, in this case, the present invention is implemented by a program stored on the control element, so that this control element provided with the program constitutes the present invention in the same manner as the method for whose execution the program is suitable.",
"An electric storage medium such as a read-only memory may be used in particular as the control element.",
"[0016] Further features, uses and advantages of the present invention come to light from the following description of exemplary embodiments of the invention which are shown in the figures of the Drawing.",
"All the features described or illustrated here, either alone or in any desired combination, constitute the object of the present invention, regardless of their combination in the patent claims or their antecedent, and regardless of how they are formulated in the description or illustrated in the Drawing.",
"BRIEF DESCRIPTION OF THE DRAWING [0017] In the following, exemplary embodiments of the present invention are explained with reference to the Drawing, in which: [0018] [0018 ]FIG. 1 shows an illustrative surroundings situation for the use of an adaptive distance and speed control;",
"[0019] [0019 ]FIG. 2 shows a first exemplary embodiment of the apparatus according to the present invention;",
"and [0020] [0020 ]FIG. 3 shows a further exemplary embodiment of the apparatus according to the present invention.",
"DESCRIPTION OF EXEMPLARY EMBODIMENTS [0021] [0021 ]FIG. 1 shows an exemplary traffic situation for the use of an adaptive distance and speed controller.",
"One can see vehicle 1 , equipped with adaptive distance and speed controller 2 , which is moving, for example, in the center lane of a multi-lane road.",
"Object detection system 2 , which may be implemented as a radar system, lidar system or video system and which is customarily mounted on the front side of vehicle 1 , detects the further objects in the surrounding field of the vehicle which are located within the sensing range whose limits are indicated by the two lines 4 .",
"Center axis 3 of the object sensing range is also drawn in, which, in the case of a radar device or lidar device, coincides with the principal beam direction of the transmitting and receiving devices.",
"A target-object selection device selects a suitable target object 5 from the objects detected by object sensing system 2 .",
"This target object is usually vehicle 5 directly in front of one's own vehicle, whose behavior from the standpoint of operating dynamics dominantly influences the control response of one's own vehicle 1 .",
"Further objects 6 are recognized only if they are moving within sensing range 4 .",
"The operating-dynamics variables of these further objects 6 achieve relevance in the case when this further object intends it, for example, by a planned cut-in maneuver between one's own vehicle 1 and preceding vehicle 5 , or when target-object vehicle 5 falls out, for example, due to a lane change, and a further preceding vehicle 6 is identified as the new target object.",
"Thus, the operating-dynamics variables of current target object 5 , as well as the operating-dynamics variables of a further detected object 6 which was recognized as a potential future target object, are relevant for the instantaneous and the future control response of vehicle 1 .",
"[0022] A first exemplary embodiment of the apparatuses according to the present invention is shown in FIG. 2. One can see a first device 7 , which, according to the present invention, has at least one object-detection device as well as a target-object selection device.",
"In the event the object-detection system is a radar system or lidar system, this first device 7 is provided with a transmitting and receiving device 8 .",
"In the case of an object-detection system in the form of an image sensing device, receiving element 8 represents a pure receiving system that, for example, may take the form of a video camera.",
"Transmitting and receiving device 8 sends out radar signals or lidar signals which, in the case of a preceding vehicle, are reflected at this object 5 , 6 and are reflected back to the transmitting and receiving device.",
"The object-detection device is able to acquire operating-dynamics variables such as the distance of object 9 , the absolute velocity or relative velocity of object 9 in relation to transmitting and receiving device 8 , the absolute acceleration or relative acceleration of object 9 in relation to the object-detection system, the lateral velocity of object 9 relative to the vehicle longitudinal axis or object-detection center axis 3 , and to provide information about whether the object-detection system is exactly adjusted, is soiled, is blinded, or whether visibility is poor.",
"From detected objects 9 , the target-object selection device, further provided in first device 7 , selects the target object whose operating-dynamics variables have a dominant effect on the distance and speed controller.",
"The target-object selection device also selects a further detected object, which was identified as a potential future target object.",
"In so doing, objects 9 are considered in particular which slip in between one's own vehicle 1 and target object 5 , or objects 6 preceding target object 5 are considered for the case when target object 5 falls out of the current traffic lane and is no longer suitable as a target object.",
"The characteristic, kinematic or operating-dynamics variables of these two objects, selected by the target-object selection device, are routed via a device for data exchange 13 to a second device 10 .",
"This second device 10 has at least one speed and distance controller.",
"In the case when no preceding object was detected, this distance and speed controller functions as a constant-speed controller, and in the case when at least one preceding object 5 was detected, functions as a constant-distance controller.",
"To that end, the operating-dynamics variables transmitted by data-exchange device 13 are routed to the distance and speed controller which generates two output signals that influence the performance.",
"These two output signals are, in particular, an output variable for controlling a power-regulating control element 11 for an internal combustion engine, particularly an electrically actuated throttle valve or an electrically controlled injection system, as well as a control signal for triggering deceleration means 12 of vehicle 1 .",
"Because first device 7 transmits only the operating-dynamics variables of two detected objects to second device 10 via data-exchange device 13 , the amount of data between first device 7 and second device 10 is kept small in comparison to systems which transmit operating-dynamics variables with respect to all detected objects.",
"Compared to systems which transmit only the operating-dynamics variables of target object 5 , a better control response results, particularly in driving situations in which target object 5 is changed, since the operating-dynamics variables of the potential new target object are already available prior to the target-object change of the distance and speed controller.",
"The modular design of this adaptive speed and distance controller makes it possible to provide first device 7 and second device 10 in separate housings, which means the first device, in a small type of construction, may be mounted on the front of the vehicle, and second device 10 may be installed at a convenient place at another location in the vehicle.",
"[0023] [0023 ]FIG. 3 shows a further specific embodiment of the apparatuses according to the present invention.",
"Again, one is able to see first device 7 , which has at least one object-detection device as well as a target-object selection device.",
"Through transmitting and receiving element 8 , which, in the case of an image recognition system, may also be implemented as a pure receiving element, radar or lidar beams are sent out which are reflected at a preceding object 9 and are received by receiving element 8 .",
"From the detected objects, the target-object selection device selects a target object which dominantly influences the controller response of the distance and speed controller, as well as a further, potential, future target object.",
"The operating-dynamics variables of these two selected objects are routed to second device 10 by data-exchange device 13 .",
"In this second device 10 , which has at least one distance and speed controller, from the transmitted, operating-dynamics variables of the two selected objects, first of all an output signal for a power-regulating control element 11 of an internal combustion engine is generated, and furthermore, an output signal is generated for controlling deceleration means 12 of the vehicle.",
"It is also within the meaning of the present invention that first device 7 and second device 10 are accommodated in a shared housing 14 , so that data-exchange device 13 represents an internal interface between two modules 7 , 10 .",
"This modular design of the adaptive speed and distance controller makes it possible to provide a standardized first device, as well as a likewise standardized second device 10 , which may be interconnected depending upon the use of this distance and speed controller.",
"[0024] It is also conceivable to provide two first devices 7 that transmit data via data-exchange devices 13 to a second device 10 in common, thereby permitting a very universal utilization of this system.",
"By the transmission of the operating-dynamics variables of two objects, the distance and speed controller, provided in second device 10 , is independent of the selection criteria of the target-object selection device in first device 7 , which means an improved control function is achieved in complex traffic situations.",
"The modular design furthermore permits better interchangeability of the object-detection system and of the control unit which acts directly on actuators 11 , 12 ."
] |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. §119(a) from Korean Patent Application No. 2008-0037595, filed on Apr. 23, 2008 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present general inventive concept relates to an image recording/reproducing device to change a start point of a fade effect so as to distinguish an image file, and a method to process a fade effect in the image recording/reproducing device.
2. Description of the Related Art
If an image is unexpectedly displayed or disappears on a screen when a moving image file is reproduced by an image recording/reproducing device, a viewing effect is reduced and an unpleasant feeling is given to a viewer. In order to solve these problems, conventionally, a fade effect is applied to a boundary between image files such that a reproduction screen is smoothly changed.
A device for applying a fade effect to an image displayed on a screen is disclosed in Korean Unexamined Patent Application Publication No. 1997-012568.
In the device for applying the fade effect disclosed in the above-mentioned publication, when a reproduction function of video information recorded on a video compact disc is started or a reproduction stop function is set in a video compact disc player to record/reproduce video information, a brightness data signal applying state of the video information is adjusted so as to control the video information to gradually fade in or out on a screen such that the viewing effect is improved.
However, in the conventional device for applying the fade effect, the fade effect is applied to a first point of a moving image, that is, a start point (first frame) of an input image. Thus, the image of the first frame is the darkest and the images of a second frame and subsequent frames thereof gradually brighten such that the brightness is returned to an original brightness of a recording start point. If the fade effect is applied to the first frame, since the image of the first frame is first displayed in a reproduction mode, a preview mode of a window explorer and an image editing application, the darkest image of the first frame is displayed. Accordingly, a user cannot check which moving image is recorded in a file which is currently being displayed.
SUMMARY OF THE INVENTION
The present general inventive concept provides an image recording/reproducing device to change a start point of a fade effect to represent a boundary between image files in a device to record/reproduce an image file so as to easily distinguish an image file displayed on a screen, and a method to process a fade effect in the image recording/reproducing device.
Additional aspects and/or advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept.
The foregoing and/or other aspects and utilities of the general inventive concept may be achieved by providing a method to process a fade effect in an image recording/reproducing device, the method including filming a moving image, encoding the filmed moving image, and applying the fade effect when the moving image is encoded and recording a moving image file such that in the moving image file, a second section to which the fade effect is applied is located after a first section to which the fade effect is not applied.
A brightness of a frame located at the first section may be brighter than that of other frames located at the second section.
A brightness of a frame located at the first section may be set to original brightness of an encoding time point.
The frame located at the first section may include a first frame of the moving image file.
A brightness of the frames located at the second section may be set to be gradually increased by the fade effect.
The frames located at the second section may include a plurality of frames including a second frame of the moving image file.
The frames located at the second section may include respective frames after the first frame of the moving image file.
The method may further include displaying the recorded moving image file such that the displaying the image of the frame of the first section which is encoded with the original brightness.
The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing an image recording/reproducing device including a video codec to encode a filmed moving image, a fade processing unit to apply a fade effect to the encoded moving image, and a controller to control an operation to record a moving image file to which the fade effect is applied and to reproduce the recorded moving image file, wherein, in the moving image file, a second section to which the fade effect is applied is located at a first section to which the fade effect is not applied.
The controller may set a frame located at the first section to an original brightness of an encoding time point.
The controller may control the moving image to be encoded in a state in which a brightness of frames located at the second section is set to be gradually increased by the fade effect.
The image recording/reproducing device may further include a displaying unit to display the recorded moving image file, wherein the controller controls the displaying unit to display the image of the first frame of the first section is encoded with the original brightness.
The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing a recording medium having embodied thereon a computer program to execute a method, the method including filming a moving image, encoding the filmed moving image, and recording a file such that a second section to which the fade effect is applied when the moving image is encoded is located after a first section to which the fade effect is not applied.
The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing an image recording/reproducing device including a fade processing unit to apply a fade effect to a moving image, and a controller to control the fade processing unit to change a start point of the fade effect to represent a boundary between image files.
The moving image may be located in a first frame displayed with an original brightness.
The start point of the fade effect representing the boundary between the image files may be changed to a second frame.
The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing a method to process a fade effect in an image recording/reproducing device, the method including applying a fade effect to a moving image by a fade processing unit, and controlling the fade processing unit to change a start point of the fade effect to represent a boundary between image files.
According to an image recording/reproducing device and a method to process a fade effect in the image recording/reproducing device of the present general inventive concept, since a start point of the fade effect representing a boundary between image files in a device to record/reproduce an image file is changed to a second frame, a first frame is displayed with original brightness. Accordingly, distinguishing the displayed file image with the fade effect in a reproduction mode, a preview mode of a window explorer and an image editing application without changing a display algorithm is possible.
BRIEF DESCRIPTION OF THE DRAWINGS
These and/or other aspects and utilities of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a block diagram illustrating an image recording/reproducing device according to an embodiment of the present general inventive concept;
FIG. 2 is a flowchart illustrating a method to process a fade effect in an image recording/reproducing device according to an embodiment of the present general inventive concept;
FIG. 3 is a view illustrating an example of encoding a moving image in the image recording/reproducing device according to the embodiment of the present general inventive concept;
FIG. 4 is a view illustrating an example of encoding a moving image in the image recording/reproducing device according to the embodiment of the present general inventive concept; and
FIG. 5 is a view illustrating a moving image file displayed on a screen of a display unit of the image recording/reproducing device according to the embodiment of the present general inventive concept.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present general inventive concept by referring to the figures.
FIG. 1 is a block diagram illustrating an image recording/reproducing device according to an embodiment of the present general inventive concept.
In FIG. 1 , the image recording/reproducing device 100 according to the embodiment of the present general inventive concept includes a camera module 102 , a video codec 104 , a fade processing unit 106 , a recording medium 108 , a controller 110 , a memory 112 , an input unit 114 and a display unit 116 .
The camera module 102 films a moving image, which is externally input, and sends an image signal to the video codec 104 , and the video codec 104 compression-encodes the image signal received from the camera module 102 in an MPEG2 format and generates an image data stream or decodes the encoded image data stream into the image signal.
When the encoding of the moving image is started by the video codec 104 , the fade processing unit 106 sets a brightness of an image of a first portion of the moving image, that is, a first frame of the input image, to original brightness of a recording start point, sets the brightness of an image of a second frame to lowest brightness, and sets the brightness of images of a third frame and subsequent frames thereof to be gradually increased such that the brightness returned to the original brightness of the recording start point, thereby processing a fade effect.
The recording medium 108 includes at least one of recording discs, to record contents such as a moving image file, which is subjected to the fade processing by the fade processing unit 106 , or to reproduce the recorded moving image file, such as a hard disc (HDD), a digital versatile disc (DVD), a memory card and a disc loader.
The controller 110 is a microcomputer to control an entire operation of the image recording/reproducing device. The controller processes the fade effect of the moving image, which is externally input, so as to record the processed moving image on the recording medium 108 , reproduces the moving image file, which is subjected to the fade processing, from the recording medium 108 , and controls the display unit 116 such that a list of moving image files is displayed on the screen in a reproduction mode, a preview mode of a window explorer and an image editing application.
The controller 110 controls the fade processing unit 106 such that the start point of the fade effect is changed when the moving image is encoded by the video codec 104 .
The memory 112 temporarily stores brightness data of the frames of the moving image, which is subjected to the fading processing by the fade processing unit 106 , or a variety of data which is generated when the controller 110 is operated.
The input unit 114 is a user interface to input a user command such that a desired moving image file is selected or a desired moving image file is reproduced via a graphic user interface (GUI).
The display unit 116 displays the first frame of the moving image file according to a control command of the controller 110 . Although the fade effect is applied to the moving image file, the image of the first frame of the moving image file is displayed with the original brightness of the recording start point. Accordingly, the moving image file which can be distinguished is displayed on a content list screen.
Hereinafter, an operation and an effect of an image recording/reproducing device and a method to process a fade effect in the image recording/reproducing device will be described.
FIG. 2 is a flowchart illustrating the method to process the fade effect in the image recording/reproducing device according to the embodiment of the present general inventive concept.
Referring to FIGS. 1 and 2 , when a moving image which is externally input is filmed by the camera module 102 and the image signal is output, the video codec 104 receives the image signal from the camera module 102 and encodes the image signal.
The controller 110 determines whether the moving image is encoded (operation 200 ) and then determines whether the first portion of the moving image is the first frame of the input image ( 202 ) if a determination is made that the moving image is encoded.
If a determination is made that the first portion of the moving image is the first frame of the input image in Operation 202 , then the controller 110 sets the brightness of the image to the original brightness of the recording start point via the fade processing unit 106 such that the image data is encoded as “frame 0 ” illustrated in FIG. 3 (operation 204 ). Since the image of the first frame of the moving image file is displayed on the screen of the display unit 116 in the reproduction mode, the preview mode of the window explorer and the image editing application, the moving image file is displayed with the original brightness such that the user can easily identify the moving image file in any mode.
Thereafter, the controller 110 determines whether the image corresponds to the second frame of the moving image (operation 206 ). If a determination is made that the image corresponds to the second frame, then the controller 110 sets the brightness of the image to the lowest brightness via the fade processing unit 106 such that the image data is encoded as “frame 1 ” illustrated in FIG. 3 (operation 208 ). Accordingly, the fade effect is applied to a boundary between the files when the moving image file is reproduced, such that a reproduction screen is smoothly switched.
Subsequently, the controller 110 determines whether the image corresponds to the third frame of the moving image (operation 210 ). If a determination is made that the image corresponds to the third frame of the moving image, then the controller 110 sets the brightness of the image to be increased via the fade processing unit 106 such that the image data is encoded as “frame 2 ” illustrated in FIG. 3 (operation 208 ). Then, a determination is made whether the image corresponds to a next moving image file (operation 214 ).
If a determination is made that the image does not correspond to the next moving image file in Operation 214 , then the method goes back to Operation 212 , and the operation to encode the image data as “frame 3 ”, “frame 4 ”, . . . illustrated in FIG. 3 by the fade effect to gradually increase the brightness of the image such that the brightness is returned to the original brightness is repeatedly performed.
Meanwhile, if the image corresponds to the next moving image file in Operation 214 , the method goes back to Operation 202 , and the operation to encode the image data of the first frame of the next moving image file with the brightness of the recording start point and encoding the image data while applying the fade effect to the second frame and the subsequent frames thereof is repeatedly performed as illustrated in FIG. 4 .
When the image data of the first frame is encoded with the brightness of the recording start point and the image data of the second frame and the subsequent frames thereof is encoded while applying the fade effect to the second frame and the subsequent frames thereof, as illustrated in FIG. 5 , the image of the first frame is displayed with the original brightness although the moving image file displayed on the content list screen of the display unit 116 is the moving image file to which the fade effect is applied. Accordingly, the contents can be distinguished.
The present general inventive concept can also be embodied as computer-readable codes on a computer-readable medium. The computer-readable medium can include a computer-readable recording medium and a computer-readable transmission medium. The computer-readable recording medium is any data storage device that can store data that can be thereafter read by a computer system. Examples of the computer-readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, and optical data storage devices. The computer-readable recording medium can also be distributed over network coupled computer systems so that the computer-readable code is stored and executed in a distributed fashion. The computer-readable transmission medium can transmit carrier waves or signals (e.g., wired or wireless data transmission through the Internet). Also, functional programs, codes, and code segments to accomplish the present general inventive concept can be easily construed by programmers skilled in the art to which the present general inventive concept pertains.
The present general inventive concept is not limited to a specific display device or application. That is, when the image of the first frame is displayed in any one of a display device, a window explorer or an image editing application, a dark image is not displayed on the screen and the image is displayed with the original brightness. Accordingly, the image file displayed on the screen can be distinguished.
Although various embodiments of the present general inventive concept have been illustrated and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the claims and their equivalents. | An image recording/reproducing device to change a start point of a fade effect to represent a boundary between image files in a device to record/reproduce an image file so as to easily distinguish an image file displayed on a screen. A method to process a fade effect in the image recording/reproducing device includes filming a moving image, encoding the filmed moving image, and applying the fade effect when the moving image is encoded and recording a moving image file. In the moving image file, a second section to which the fade effect is applied is located after a first section to which the fade effect is not applied. Accordingly, distinguishing the moving image file with the fade effect in a reproduction mode, a preview mode of a window explorer and an image editing application without changing an algorithm is possible. | Briefly outline the background technology and the problem the invention aims to solve. | [
"CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. §119(a) from Korean Patent Application No. 2008-0037595, filed on Apr. 23, 2008 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present general inventive concept relates to an image recording/reproducing device to change a start point of a fade effect so as to distinguish an image file, and a method to process a fade effect in the image recording/reproducing device.",
"Description of the Related Art If an image is unexpectedly displayed or disappears on a screen when a moving image file is reproduced by an image recording/reproducing device, a viewing effect is reduced and an unpleasant feeling is given to a viewer.",
"In order to solve these problems, conventionally, a fade effect is applied to a boundary between image files such that a reproduction screen is smoothly changed.",
"A device for applying a fade effect to an image displayed on a screen is disclosed in Korean Unexamined Patent Application Publication No. 1997-012568.",
"In the device for applying the fade effect disclosed in the above-mentioned publication, when a reproduction function of video information recorded on a video compact disc is started or a reproduction stop function is set in a video compact disc player to record/reproduce video information, a brightness data signal applying state of the video information is adjusted so as to control the video information to gradually fade in or out on a screen such that the viewing effect is improved.",
"However, in the conventional device for applying the fade effect, the fade effect is applied to a first point of a moving image, that is, a start point (first frame) of an input image.",
"Thus, the image of the first frame is the darkest and the images of a second frame and subsequent frames thereof gradually brighten such that the brightness is returned to an original brightness of a recording start point.",
"If the fade effect is applied to the first frame, since the image of the first frame is first displayed in a reproduction mode, a preview mode of a window explorer and an image editing application, the darkest image of the first frame is displayed.",
"Accordingly, a user cannot check which moving image is recorded in a file which is currently being displayed.",
"SUMMARY OF THE INVENTION The present general inventive concept provides an image recording/reproducing device to change a start point of a fade effect to represent a boundary between image files in a device to record/reproduce an image file so as to easily distinguish an image file displayed on a screen, and a method to process a fade effect in the image recording/reproducing device.",
"Additional aspects and/or advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept.",
"The foregoing and/or other aspects and utilities of the general inventive concept may be achieved by providing a method to process a fade effect in an image recording/reproducing device, the method including filming a moving image, encoding the filmed moving image, and applying the fade effect when the moving image is encoded and recording a moving image file such that in the moving image file, a second section to which the fade effect is applied is located after a first section to which the fade effect is not applied.",
"A brightness of a frame located at the first section may be brighter than that of other frames located at the second section.",
"A brightness of a frame located at the first section may be set to original brightness of an encoding time point.",
"The frame located at the first section may include a first frame of the moving image file.",
"A brightness of the frames located at the second section may be set to be gradually increased by the fade effect.",
"The frames located at the second section may include a plurality of frames including a second frame of the moving image file.",
"The frames located at the second section may include respective frames after the first frame of the moving image file.",
"The method may further include displaying the recorded moving image file such that the displaying the image of the frame of the first section which is encoded with the original brightness.",
"The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing an image recording/reproducing device including a video codec to encode a filmed moving image, a fade processing unit to apply a fade effect to the encoded moving image, and a controller to control an operation to record a moving image file to which the fade effect is applied and to reproduce the recorded moving image file, wherein, in the moving image file, a second section to which the fade effect is applied is located at a first section to which the fade effect is not applied.",
"The controller may set a frame located at the first section to an original brightness of an encoding time point.",
"The controller may control the moving image to be encoded in a state in which a brightness of frames located at the second section is set to be gradually increased by the fade effect.",
"The image recording/reproducing device may further include a displaying unit to display the recorded moving image file, wherein the controller controls the displaying unit to display the image of the first frame of the first section is encoded with the original brightness.",
"The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing a recording medium having embodied thereon a computer program to execute a method, the method including filming a moving image, encoding the filmed moving image, and recording a file such that a second section to which the fade effect is applied when the moving image is encoded is located after a first section to which the fade effect is not applied.",
"The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing an image recording/reproducing device including a fade processing unit to apply a fade effect to a moving image, and a controller to control the fade processing unit to change a start point of the fade effect to represent a boundary between image files.",
"The moving image may be located in a first frame displayed with an original brightness.",
"The start point of the fade effect representing the boundary between the image files may be changed to a second frame.",
"The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing a method to process a fade effect in an image recording/reproducing device, the method including applying a fade effect to a moving image by a fade processing unit, and controlling the fade processing unit to change a start point of the fade effect to represent a boundary between image files.",
"According to an image recording/reproducing device and a method to process a fade effect in the image recording/reproducing device of the present general inventive concept, since a start point of the fade effect representing a boundary between image files in a device to record/reproduce an image file is changed to a second frame, a first frame is displayed with original brightness.",
"Accordingly, distinguishing the displayed file image with the fade effect in a reproduction mode, a preview mode of a window explorer and an image editing application without changing a display algorithm is possible.",
"BRIEF DESCRIPTION OF THE DRAWINGS These and/or other aspects and utilities of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: FIG. 1 is a block diagram illustrating an image recording/reproducing device according to an embodiment of the present general inventive concept;",
"FIG. 2 is a flowchart illustrating a method to process a fade effect in an image recording/reproducing device according to an embodiment of the present general inventive concept;",
"FIG. 3 is a view illustrating an example of encoding a moving image in the image recording/reproducing device according to the embodiment of the present general inventive concept;",
"FIG. 4 is a view illustrating an example of encoding a moving image in the image recording/reproducing device according to the embodiment of the present general inventive concept;",
"and FIG. 5 is a view illustrating a moving image file displayed on a screen of a display unit of the image recording/reproducing device according to the embodiment of the present general inventive concept.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.",
"The embodiments are described below to explain the present general inventive concept by referring to the figures.",
"FIG. 1 is a block diagram illustrating an image recording/reproducing device according to an embodiment of the present general inventive concept.",
"In FIG. 1 , the image recording/reproducing device 100 according to the embodiment of the present general inventive concept includes a camera module 102 , a video codec 104 , a fade processing unit 106 , a recording medium 108 , a controller 110 , a memory 112 , an input unit 114 and a display unit 116 .",
"The camera module 102 films a moving image, which is externally input, and sends an image signal to the video codec 104 , and the video codec 104 compression-encodes the image signal received from the camera module 102 in an MPEG2 format and generates an image data stream or decodes the encoded image data stream into the image signal.",
"When the encoding of the moving image is started by the video codec 104 , the fade processing unit 106 sets a brightness of an image of a first portion of the moving image, that is, a first frame of the input image, to original brightness of a recording start point, sets the brightness of an image of a second frame to lowest brightness, and sets the brightness of images of a third frame and subsequent frames thereof to be gradually increased such that the brightness returned to the original brightness of the recording start point, thereby processing a fade effect.",
"The recording medium 108 includes at least one of recording discs, to record contents such as a moving image file, which is subjected to the fade processing by the fade processing unit 106 , or to reproduce the recorded moving image file, such as a hard disc (HDD), a digital versatile disc (DVD), a memory card and a disc loader.",
"The controller 110 is a microcomputer to control an entire operation of the image recording/reproducing device.",
"The controller processes the fade effect of the moving image, which is externally input, so as to record the processed moving image on the recording medium 108 , reproduces the moving image file, which is subjected to the fade processing, from the recording medium 108 , and controls the display unit 116 such that a list of moving image files is displayed on the screen in a reproduction mode, a preview mode of a window explorer and an image editing application.",
"The controller 110 controls the fade processing unit 106 such that the start point of the fade effect is changed when the moving image is encoded by the video codec 104 .",
"The memory 112 temporarily stores brightness data of the frames of the moving image, which is subjected to the fading processing by the fade processing unit 106 , or a variety of data which is generated when the controller 110 is operated.",
"The input unit 114 is a user interface to input a user command such that a desired moving image file is selected or a desired moving image file is reproduced via a graphic user interface (GUI).",
"The display unit 116 displays the first frame of the moving image file according to a control command of the controller 110 .",
"Although the fade effect is applied to the moving image file, the image of the first frame of the moving image file is displayed with the original brightness of the recording start point.",
"Accordingly, the moving image file which can be distinguished is displayed on a content list screen.",
"Hereinafter, an operation and an effect of an image recording/reproducing device and a method to process a fade effect in the image recording/reproducing device will be described.",
"FIG. 2 is a flowchart illustrating the method to process the fade effect in the image recording/reproducing device according to the embodiment of the present general inventive concept.",
"Referring to FIGS. 1 and 2 , when a moving image which is externally input is filmed by the camera module 102 and the image signal is output, the video codec 104 receives the image signal from the camera module 102 and encodes the image signal.",
"The controller 110 determines whether the moving image is encoded (operation 200 ) and then determines whether the first portion of the moving image is the first frame of the input image ( 202 ) if a determination is made that the moving image is encoded.",
"If a determination is made that the first portion of the moving image is the first frame of the input image in Operation 202 , then the controller 110 sets the brightness of the image to the original brightness of the recording start point via the fade processing unit 106 such that the image data is encoded as “frame 0 ”",
"illustrated in FIG. 3 (operation 204 ).",
"Since the image of the first frame of the moving image file is displayed on the screen of the display unit 116 in the reproduction mode, the preview mode of the window explorer and the image editing application, the moving image file is displayed with the original brightness such that the user can easily identify the moving image file in any mode.",
"Thereafter, the controller 110 determines whether the image corresponds to the second frame of the moving image (operation 206 ).",
"If a determination is made that the image corresponds to the second frame, then the controller 110 sets the brightness of the image to the lowest brightness via the fade processing unit 106 such that the image data is encoded as “frame 1 ”",
"illustrated in FIG. 3 (operation 208 ).",
"Accordingly, the fade effect is applied to a boundary between the files when the moving image file is reproduced, such that a reproduction screen is smoothly switched.",
"Subsequently, the controller 110 determines whether the image corresponds to the third frame of the moving image (operation 210 ).",
"If a determination is made that the image corresponds to the third frame of the moving image, then the controller 110 sets the brightness of the image to be increased via the fade processing unit 106 such that the image data is encoded as “frame 2 ”",
"illustrated in FIG. 3 (operation 208 ).",
"Then, a determination is made whether the image corresponds to a next moving image file (operation 214 ).",
"If a determination is made that the image does not correspond to the next moving image file in Operation 214 , then the method goes back to Operation 212 , and the operation to encode the image data as “frame 3 ”, “frame 4 ”, .",
"illustrated in FIG. 3 by the fade effect to gradually increase the brightness of the image such that the brightness is returned to the original brightness is repeatedly performed.",
"Meanwhile, if the image corresponds to the next moving image file in Operation 214 , the method goes back to Operation 202 , and the operation to encode the image data of the first frame of the next moving image file with the brightness of the recording start point and encoding the image data while applying the fade effect to the second frame and the subsequent frames thereof is repeatedly performed as illustrated in FIG. 4 .",
"When the image data of the first frame is encoded with the brightness of the recording start point and the image data of the second frame and the subsequent frames thereof is encoded while applying the fade effect to the second frame and the subsequent frames thereof, as illustrated in FIG. 5 , the image of the first frame is displayed with the original brightness although the moving image file displayed on the content list screen of the display unit 116 is the moving image file to which the fade effect is applied.",
"Accordingly, the contents can be distinguished.",
"The present general inventive concept can also be embodied as computer-readable codes on a computer-readable medium.",
"The computer-readable medium can include a computer-readable recording medium and a computer-readable transmission medium.",
"The computer-readable recording medium is any data storage device that can store data that can be thereafter read by a computer system.",
"Examples of the computer-readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, and optical data storage devices.",
"The computer-readable recording medium can also be distributed over network coupled computer systems so that the computer-readable code is stored and executed in a distributed fashion.",
"The computer-readable transmission medium can transmit carrier waves or signals (e.g., wired or wireless data transmission through the Internet).",
"Also, functional programs, codes, and code segments to accomplish the present general inventive concept can be easily construed by programmers skilled in the art to which the present general inventive concept pertains.",
"The present general inventive concept is not limited to a specific display device or application.",
"That is, when the image of the first frame is displayed in any one of a display device, a window explorer or an image editing application, a dark image is not displayed on the screen and the image is displayed with the original brightness.",
"Accordingly, the image file displayed on the screen can be distinguished.",
"Although various embodiments of the present general inventive concept have been illustrated and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the claims and their equivalents."
] |
TECHNICAL FIELD
This disclosure relates to feeds and, more particularly, to representing multi-attachments within feeds.
BACKGROUND
Web feeds are used to distribute information to subscribers and visitors of a website. Various feed formats (e.g., RSS & Atom) may be utilized to achieve the desired data distribution. Unfortunately, some feed formats are limited in the manner in which data may be distributed. For example, problems are often encountered when trying to distribute pages that include a plurality of attachments (i.e., data objects) that are related to each other in some way yet need to be dispersed throughout the feed.
Specifically, a page represented by an Atom feed may be made up of multiple feed entries within the Atom feed, wherein each feed entry within the feed represents a data object within the page (e.g., an attachment). Unfortunately, for such an Atom feed, there is no way to reconstruct the original page composition if the original page included multiple data objects (e.g., attachments, fields, and/or metadata) and such given objects were dispersed throughout the feed rather than within a single holding object.
SUMMARY OF DISCLOSURE
In a first implementation, a method includes processing a data page to be provided to one or more remote devices via a data feed. A determination is made concerning whether the data page includes two or more data objects. If the data page includes two or more data objects, a page entry for the data page is defined; and a separate object entry for at least one of the two or more data objects included within the data page is defined. The object entry is associated with the page entry.
One or more of the following features may be included. The page entry and the object entry may be provided to at least one of the one or more remote devices. Providing the page entry and the object entry to at least one of the one or more remote devices may include publishing the page entry and the object entry to at least one of the one or more remote devices. Providing the page entry and the object entry to at least one of the one or more remote devices may include enabling availability of the page entry and the object entry to at least one of the one or more remote devices.
The data feed may be an RSS feed. The data feed may be an ATOM feed. At least one of the data objects may be an attachment. At least one of the data objects may be a data field. The page entry may include a master entry ID. The object entry may include a slave entry ID that is associated with the master entry ID. The slave entry ID may include at least a portion of the master entry ID.
In another implementation, a computer program product resides on a computer readable medium that has a plurality of instructions stored on it. When executed by a processor, the instructions cause the processor to perform operations including processing a data page to be provided to one or more remote devices via a data feed. A determination is made concerning whether the data page includes two or more data objects. If the data page includes two or more data objects, a page entry for the data page is defined; and a separate object entry for at least one of the two or more data objects included within the data page is defined. The object entry is associated with the page entry.
One or more of the following features may be included. The page entry and the object entry may be provided to at least one of the one or more remote devices. Providing the page entry and the object entry to at least one of the one or more remote devices may include publishing the page entry and the object entry to at least one of the one or more remote devices. Providing the page entry and the object entry to at least one of the one or more remote devices may include enabling availability of the page entry and the object entry to at least one of the one or more remote devices.
The data feed may be an RSS feed. The data feed may be an ATOM feed. At least one of the data objects may be an attachment. At least one of the data objects may be a data field. The page entry may include a master entry ID. The object entry may include a slave entry ID that is associated with the master entry ID. The slave entry ID may include at least a portion of the master entry ID.
The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will become apparent from the description, the drawings, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic view of a feed generation process and feed reading processes coupled to a distributed computing network;
FIG. 2 is a diagrammatic view of a display screen rendered by a client electronic device; and
FIG. 3 is a diagrammatic view of a web feed generated by the feed generation process of FIG. 1 ; and
FIG. 4 is a flowchart of the feed generation process of FIG. 1 .
Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
System Overview:
Referring to FIG. 1 , there is shown feed generation process 10 that may reside on and may be executed by server computer 12 , which may be connected to network 14 (e.g., the Internet or a local area network). Examples of server computer 12 may include, but are not limited to: a personal computer, a server computer, a series of server computers, a mini computer, and a mainframe computer. Server computer 12 may be a web server (or a series of servers) running a network operating system, examples of which may include but are not limited to: Microsoft Windows XP Server™; Novell Netware™; or Redhat Linux™, for example.
As will be discussed below in greater detail, feed generation process 10 may process a data page to be provided to one or more remote devices via a data feed. Feed generation process 10 may determine if the data page includes two or more data objects. If so, a page entry for the data page may be defined and an object entry for at least one of the data objects included within the data page may be defined, wherein the object entry is associated with the page entry.
The instruction sets and subroutines of feed generation process 10 , which may be stored on storage device 16 coupled to server computer 12 , may be executed by one or more processors (not shown) and one or more memory architectures (not shown) incorporated into server computer 12 . Storage device 16 may include but is not limited to: a hard disk drive; a tape drive; an optical drive; a RAID array; a random access memory (RAM); and a read-only memory (ROM).
Server computer 12 may execute a web server application, examples of which may include but are not limited to: Microsoft IIS™, Novell Webserver™, or Apache Webserver™, that allows for HTTP (i.e., HyperText Transfer Protocol) access to server computer 12 via network 14 . Network 14 may be connected to one or more secondary networks (e.g., network 18 ), examples of which may include but are not limited to: a local area network; a wide area network; or an intranet, for example.
Server computer 12 may execute syndication application 20 , examples of which may include but are not limited to IBM Workplace Web Content Management™. Syndication application 20 may allow for the transferring of information via data feeds, such as RSS feeds and Atom feeds to one or more feed reading processes 22 , 24 , 26 , 28 , examples of which may include but are not limited to Google Reader™ and NewsGator™. Feed generation process 10 may be a stand alone application that interfaces with syndication application 20 or an applet/application that is executed within syndication application 20 .
The instruction sets and subroutines of syndication application 20 , which may be stored on storage device 16 coupled to server computer 12 may be executed by one or more processors (not shown) and one or more memory architectures (not shown) incorporated into server computer 12 .
The instruction sets and subroutines of feed reading processes 22 , 24 , 26 , 28 , which may be stored on storage devices 30 , 32 , 34 , 36 (respectively) coupled to client electronic devices 38 , 40 , 42 , 44 (respectively), may be executed by one or more processors (not shown) and one or more memory architectures (not shown) incorporated into client electronic devices 38 , 40 , 42 , 44 (respectively). Storage devices 30 , 32 , 34 , 36 may include but are not limited to: hard disk drives; tape drives; optical drives; RAID arrays; random access memories (RAM); read-only memories (ROM), compact flash (CF) storage devices, secure digital (SD) storage devices, and memory stick storage devices. Examples of client electronic devices 38 , 40 , 42 , 44 may include, but are not limited to, personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 , a server (not shown), a data-enabled, cellular telephone (not shown), and a dedicated network device (not shown). Using feed reading processes 22 , 24 , 26 , 28 , users 46 , 48 , 50 , 52 (respectively) may access feeds provided by syndication application 20 .
Users 46 , 48 , 50 , 52 may access syndication application 20 directly through the device on which the feed reading process (e.g., feed reading processes 22 , 24 , 26 , 28 ) is executed, namely client electronic devices 38 , 40 , 42 , 44 , for example. Users 46 , 48 , 50 , 52 may access syndication application 20 directly through network 14 or through secondary network 18 . Further, server computer 12 (i.e., the computer that executes syndication application 20 ) may be connected to network 14 through secondary network 18 , as illustrated with phantom link line 54 .
The various client electronic devices may be directly or indirectly coupled to network 14 (or network 18 ). For example, personal computer 38 is shown directly coupled to network 14 via a hardwired network connection. Further, notebook computer 44 is shown directly coupled to network 18 via a hardwired network connection. Laptop computer 40 is shown wirelessly coupled to network 14 via wireless communication channel 56 established between laptop computer 40 and wireless access point (i.e., WAP) 58 , which is shown directly coupled to network 14 . WAP 58 may be, for example, an IEEE 802.11a, 802.11b, 802.11g, Wi-Fi, and/or Bluetooth device that is capable of establishing wireless communication channel 56 between laptop computer 40 and WAP 58 . Personal digital assistant 42 is shown wirelessly coupled to network 14 via wireless communication channel 60 established between personal digital assistant 42 and cellular network/bridge 62 , which is shown directly coupled to network 14 .
As is known in the art, all of the IEEE 802.11x specifications may use Ethernet protocol and carrier sense multiple access with collision avoidance (i.e., CSMA/CA) for path sharing. The various 802.11x specifications may use phase-shift keying (i.e., PSK) modulation or complementary code keying (i.e., CCK) modulation, for example. As is known in the art, Bluetooth is a telecommunications industry specification that allows e.g., mobile phones, computers, and personal digital assistants to be interconnected using a short-range wireless connection.
Client electronic devices 38 , 40 , 42 , 44 may each execute an operating system, examples of which may include but are not limited to Microsoft Windows™, Microsoft Windows CE™, Redhat Linux™, or a custom operating system.
The Feed Generation Process:
For the following discussion, feed reading process 22 is going to be described for illustrative purposes. However, this is not intended to be a limitation of this disclosure, as other feed reading processes (e.g., feed reading processes 24 , 26 , 28 ) may be equally utilized.
Referring also to FIGS. 2 & 3 and as discussed above, feed generation process 10 may process 100 a data page (such as a TeamSpace™ page) to be provided to one or more remote devices (e.g., client electronic devices 38 , 40 , 42 , 44 ) via a data feed (e.g., an RSS feed or an ATOM feed). As is known in the art, a TeamSpace may be a web-based collaborative workspace system for managing shared work processes and maintaining shared artifacts in a project that may span months/years. A TeamSpace may cover both synchronous and asynchronous cross-company team activities and may provide a seamless transition between various work modes.
Feed reading process 22 may allow user 46 to browse through various sites (e.g. websites and team spaces) so that user 46 may subscribe to one or more web feeds. For example, using feed reading process 22 , user 46 may browse team space 100 (i.e. “Tony's Team Page”). Team space 100 may include menu bar 102 that allows user 46 to select from a plurality of sub pages, such as “Home”, “Discussion”, “Library”, “Calendar”, “Tasks”, “Index”, “Customize”, and “Members”. Team space 100 may include subscription button 104 that allows user 46 to subscribe to web feed 150 .
As discussed above, web feeds may be used to distribute information to subscribers and visitors of a website. Accordingly, web feed 150 may be used to distribute information available on team space page 100 . For example, team space page 100 is shown to include three files available for download, namely: Test_Image.gif; Error_Log.txt; and Chicago_Slideshow.PPT. Accordingly, through the use of web feed 150 , user 46 may receive content distributed by e.g. team space page 100 , including but not limited to the three files available for download, namely: Test_Image.gif; Error_Log.txt; and Chicago_Slideshow.PPT.
While the content distributor is described above is being team space page 100 , this is for illustrative purposes only and is not intended to be a limitation of this disclosure, as other configurations are possible. For example, the content distributor may be a news website, a blog site, or a social networking website.
As discussed above, various feed formats (e.g., RSS & Atom) may be utilized to achieve the desired data distribution. Unfortunately, for certain feed types (e.g., Atom feeds), it is not possible to reconstruct “complex” pages (i.e., pages that include multiple data objects, such as attachments, fields, metadata, etc). Accordingly, as team space page 100 includes three attachments, this is a “complex” page that may be difficult to reconstruct when transmitted using various feed formats.
Accordingly and referring also to FIG. 4 , when a user (e.g. user 46 ) selects subscription button 104 , thus indicating that (in this particular example) user 46 wishes to subscribe to a web feed of team space page 100 , feed generation process 10 may process 200 team space page 100 (i.e. the page that is to be provided to the remote devices (e.g. personal computer 38 ) via data feed 150 ) to determine 202 whether team space page 100 includes two or more data objects. In the event that team space page 100 does not include multiple objects, feed generation process 10 may publish 204 a feed of the data included within team space page 100 . However and as discussed above, since team space page 100 includes a plurality of attachments, namely: Test_Image.gif 106 ; Error_Log.txt 108 ; and Chicago_Slideshow.PPT 110 , team space page 100 does indeed include two or more data objects.
Accordingly, upon feed generation process 10 determining 202 that team space page 100 includes multiple objects, feed generation process 10 may define 206 a page entry for the data page (i.e. team space page 100 ) and may define 208 an object entry for each of the data objects included within team space page 100 (i.e. Test_Image.gif 106 ; Error_Log.txt 108 ; and Chicago_Slideshow.PPT 110 ).
As is known in the art, web feeds (e.g. web feed 150 ) may include a plurality of feed entries. Therefore, when publishing web feed 150 , feed generation process 10 may include, within web feed 150 , the page entry defined 204 for team space page 100 and the object entries defined 206 for Test_Image.gif 106 ; Error_Log.txt 108 ; and Chicago_Slideshow.PPT 110 .
For illustrative purposes, web feed 150 is shown to include the four above-described feed entries, namely page entry 152 (which corresponds to team space page 100 ), object entry 154 (which corresponds to Test_Image.gif 106 ), object entry 156 (which corresponds to Error_Log.txt 108 ), and object entry 158 (which corresponds to Chicago_Slideshow.PPT 110 ). When generating web feed 150 , feed generation process 10 may also include additional information 160 , 162 that may be required to e.g. define the feed type, define the beginning of the feed, and define the end of the feed).
Page entry 152 may define various aspects of team space page 100 , such as: the title of the page (“Tony's Team Page”); the publication date of the page; and the author of the page. Each of object entries 154 , 156 , 158 may define various aspects of the related data object, such as: the title of the data object; the publication date of the data object; and the author of the data object.
When defining 208 the object entries (e.g., object entries 154 , 156 , 158 ), feed generation process 10 may associate each object entry defined within web feed 150 with the related page entry (e.g., page entry 152 ), thus allowing web feed 150 to be properly processed by feed reading process 22 . For example, each page entry (e.g. page entry 152 ) may include a master entry ID. Further, each object entry (e.g. object entries 154 , 156 , 158 ) may include a slave entry ID that is associated with the master entry ID, and the slave entry ID included within each object entry may include at least a portion of the master entry ID.
For example and for illustrative purposes only, page entry 152 may include master ID entry 164 (i.e. 0F7F78B411663465852572DB00775018). Further, object entry 154 may include slave entry ID 166 (i.e. 0F7F78B411663465852572DB00775018.1); object entry 156 may include slave entry ID 168 (i.e., 0F7F78B411663465852572DB00775018.2); and object entry 156 may include slave entry ID 170 (i.e., 0F7F78B411663465852572DB00775018.3). In this example, slave entry IDs 166 , 168 , 170 are shown to be identical to master entry ID 164 with the exception that a suffix (e.g. “0.1”, “0.2”, “0.3”, respectively) was added to each of slave entry IDs 166 , 168 , 170 . Accordingly, the “root” portion (i.e. 0F7F78B411663465852572DB00775018) of each of slave entry IDs 166 , 168 , 170 is identical to that of master ID entry 164 (i.e. 0F7F78B411663465852572DB00775018). Accordingly, by using such a master entry ID/slave entry ID nomenclature, feed generation process 10 may associate each object entry (e.g., object entries 154 , 156 , 158 ) defined within web feed 150 with the related page entry (e.g., page entry 152 ).
The above-described master entry ID/slave entry ID nomenclature is for illustrative purposes only and is not intended to be a limitation of this disclosure, as other configurations are possible. For example, instead of attaching a suffix to each of slave entry IDs 166 , 168 , 170 , an additional line item may be inserted into each of the corresponding object entries (namely object entries 154 , 156 , 158 ) that defines the associated page entry (namely page entry 152 ).
Once web feed 150 is defined, feed generation process 10 and/or syndication application 20 may provide 210 web feed 150 (which includes page entry 152 and object entries 154 , 156 , 158 ) to one or more remote devices (e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 ).
When providing web feed 150 (which includes page entry 152 and object entries 154 , 156 , 158 ) to e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 , feed generation process 10 and/or syndication application 20 may publish 212 web feed 150 to the remote devices. Accordingly, feed generation process 10 and/or syndication application 20 may transmit web feed 150 to e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 .
Alternatively/additionally, when providing web feed 150 (which includes page entry 152 and object entries 154 , 156 , 158 ) to e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 , feed generation process 10 and/or syndication application 20 may enable availability 214 of web feed 150 to e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 . Accordingly, feed generation process 10 and/or syndication application 20 may allow users of e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 to download/obtain a copy of web feed 150 (e.g. in a manner similar to that of a podcast).
A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. Accordingly, other implementations are within the scope of the following claims. | A method and computer program product for processing a data page to be provided to one or more remote devices via a data feed. A determination is made concerning whether the data page includes two or more data objects. If the data page includes two or more data objects, a page entry for the data page is defined; and a separate object entry for at least one of the two or more data objects included within the data page is defined. The object entry is associated with the page entry. | Summarize the document in concise, focusing on the main idea's functionality and advantages. | [
"TECHNICAL FIELD This disclosure relates to feeds and, more particularly, to representing multi-attachments within feeds.",
"BACKGROUND Web feeds are used to distribute information to subscribers and visitors of a website.",
"Various feed formats (e.g., RSS &",
"Atom) may be utilized to achieve the desired data distribution.",
"Unfortunately, some feed formats are limited in the manner in which data may be distributed.",
"For example, problems are often encountered when trying to distribute pages that include a plurality of attachments (i.e., data objects) that are related to each other in some way yet need to be dispersed throughout the feed.",
"Specifically, a page represented by an Atom feed may be made up of multiple feed entries within the Atom feed, wherein each feed entry within the feed represents a data object within the page (e.g., an attachment).",
"Unfortunately, for such an Atom feed, there is no way to reconstruct the original page composition if the original page included multiple data objects (e.g., attachments, fields, and/or metadata) and such given objects were dispersed throughout the feed rather than within a single holding object.",
"SUMMARY OF DISCLOSURE In a first implementation, a method includes processing a data page to be provided to one or more remote devices via a data feed.",
"A determination is made concerning whether the data page includes two or more data objects.",
"If the data page includes two or more data objects, a page entry for the data page is defined;",
"and a separate object entry for at least one of the two or more data objects included within the data page is defined.",
"The object entry is associated with the page entry.",
"One or more of the following features may be included.",
"The page entry and the object entry may be provided to at least one of the one or more remote devices.",
"Providing the page entry and the object entry to at least one of the one or more remote devices may include publishing the page entry and the object entry to at least one of the one or more remote devices.",
"Providing the page entry and the object entry to at least one of the one or more remote devices may include enabling availability of the page entry and the object entry to at least one of the one or more remote devices.",
"The data feed may be an RSS feed.",
"The data feed may be an ATOM feed.",
"At least one of the data objects may be an attachment.",
"At least one of the data objects may be a data field.",
"The page entry may include a master entry ID.",
"The object entry may include a slave entry ID that is associated with the master entry ID.",
"The slave entry ID may include at least a portion of the master entry ID.",
"In another implementation, a computer program product resides on a computer readable medium that has a plurality of instructions stored on it.",
"When executed by a processor, the instructions cause the processor to perform operations including processing a data page to be provided to one or more remote devices via a data feed.",
"A determination is made concerning whether the data page includes two or more data objects.",
"If the data page includes two or more data objects, a page entry for the data page is defined;",
"and a separate object entry for at least one of the two or more data objects included within the data page is defined.",
"The object entry is associated with the page entry.",
"One or more of the following features may be included.",
"The page entry and the object entry may be provided to at least one of the one or more remote devices.",
"Providing the page entry and the object entry to at least one of the one or more remote devices may include publishing the page entry and the object entry to at least one of the one or more remote devices.",
"Providing the page entry and the object entry to at least one of the one or more remote devices may include enabling availability of the page entry and the object entry to at least one of the one or more remote devices.",
"The data feed may be an RSS feed.",
"The data feed may be an ATOM feed.",
"At least one of the data objects may be an attachment.",
"At least one of the data objects may be a data field.",
"The page entry may include a master entry ID.",
"The object entry may include a slave entry ID that is associated with the master entry ID.",
"The slave entry ID may include at least a portion of the master entry ID.",
"The details of one or more implementations are set forth in the accompanying drawings and the description below.",
"Other features and advantages will become apparent from the description, the drawings, and the claims.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view of a feed generation process and feed reading processes coupled to a distributed computing network;",
"FIG. 2 is a diagrammatic view of a display screen rendered by a client electronic device;",
"and FIG. 3 is a diagrammatic view of a web feed generated by the feed generation process of FIG. 1 ;",
"and FIG. 4 is a flowchart of the feed generation process of FIG. 1 .",
"Like reference symbols in the various drawings indicate like elements.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS System Overview: Referring to FIG. 1 , there is shown feed generation process 10 that may reside on and may be executed by server computer 12 , which may be connected to network 14 (e.g., the Internet or a local area network).",
"Examples of server computer 12 may include, but are not limited to: a personal computer, a server computer, a series of server computers, a mini computer, and a mainframe computer.",
"Server computer 12 may be a web server (or a series of servers) running a network operating system, examples of which may include but are not limited to: Microsoft Windows XP Server™;",
"Novell Netware™;",
"or Redhat Linux™, for example.",
"As will be discussed below in greater detail, feed generation process 10 may process a data page to be provided to one or more remote devices via a data feed.",
"Feed generation process 10 may determine if the data page includes two or more data objects.",
"If so, a page entry for the data page may be defined and an object entry for at least one of the data objects included within the data page may be defined, wherein the object entry is associated with the page entry.",
"The instruction sets and subroutines of feed generation process 10 , which may be stored on storage device 16 coupled to server computer 12 , may be executed by one or more processors (not shown) and one or more memory architectures (not shown) incorporated into server computer 12 .",
"Storage device 16 may include but is not limited to: a hard disk drive;",
"a tape drive;",
"an optical drive;",
"a RAID array;",
"a random access memory (RAM);",
"and a read-only memory (ROM).",
"Server computer 12 may execute a web server application, examples of which may include but are not limited to: Microsoft IIS™, Novell Webserver™, or Apache Webserver™, that allows for HTTP (i.e., HyperText Transfer Protocol) access to server computer 12 via network 14 .",
"Network 14 may be connected to one or more secondary networks (e.g., network 18 ), examples of which may include but are not limited to: a local area network;",
"a wide area network;",
"or an intranet, for example.",
"Server computer 12 may execute syndication application 20 , examples of which may include but are not limited to IBM Workplace Web Content Management™.",
"Syndication application 20 may allow for the transferring of information via data feeds, such as RSS feeds and Atom feeds to one or more feed reading processes 22 , 24 , 26 , 28 , examples of which may include but are not limited to Google Reader™ and NewsGator™.",
"Feed generation process 10 may be a stand alone application that interfaces with syndication application 20 or an applet/application that is executed within syndication application 20 .",
"The instruction sets and subroutines of syndication application 20 , which may be stored on storage device 16 coupled to server computer 12 may be executed by one or more processors (not shown) and one or more memory architectures (not shown) incorporated into server computer 12 .",
"The instruction sets and subroutines of feed reading processes 22 , 24 , 26 , 28 , which may be stored on storage devices 30 , 32 , 34 , 36 (respectively) coupled to client electronic devices 38 , 40 , 42 , 44 (respectively), may be executed by one or more processors (not shown) and one or more memory architectures (not shown) incorporated into client electronic devices 38 , 40 , 42 , 44 (respectively).",
"Storage devices 30 , 32 , 34 , 36 may include but are not limited to: hard disk drives;",
"tape drives;",
"optical drives;",
"RAID arrays;",
"random access memories (RAM);",
"read-only memories (ROM), compact flash (CF) storage devices, secure digital (SD) storage devices, and memory stick storage devices.",
"Examples of client electronic devices 38 , 40 , 42 , 44 may include, but are not limited to, personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 , a server (not shown), a data-enabled, cellular telephone (not shown), and a dedicated network device (not shown).",
"Using feed reading processes 22 , 24 , 26 , 28 , users 46 , 48 , 50 , 52 (respectively) may access feeds provided by syndication application 20 .",
"Users 46 , 48 , 50 , 52 may access syndication application 20 directly through the device on which the feed reading process (e.g., feed reading processes 22 , 24 , 26 , 28 ) is executed, namely client electronic devices 38 , 40 , 42 , 44 , for example.",
"Users 46 , 48 , 50 , 52 may access syndication application 20 directly through network 14 or through secondary network 18 .",
"Further, server computer 12 (i.e., the computer that executes syndication application 20 ) may be connected to network 14 through secondary network 18 , as illustrated with phantom link line 54 .",
"The various client electronic devices may be directly or indirectly coupled to network 14 (or network 18 ).",
"For example, personal computer 38 is shown directly coupled to network 14 via a hardwired network connection.",
"Further, notebook computer 44 is shown directly coupled to network 18 via a hardwired network connection.",
"Laptop computer 40 is shown wirelessly coupled to network 14 via wireless communication channel 56 established between laptop computer 40 and wireless access point (i.e., WAP) 58 , which is shown directly coupled to network 14 .",
"WAP 58 may be, for example, an IEEE 802.11a, 802.11b, 802.11g, Wi-Fi, and/or Bluetooth device that is capable of establishing wireless communication channel 56 between laptop computer 40 and WAP 58 .",
"Personal digital assistant 42 is shown wirelessly coupled to network 14 via wireless communication channel 60 established between personal digital assistant 42 and cellular network/bridge 62 , which is shown directly coupled to network 14 .",
"As is known in the art, all of the IEEE 802.11x specifications may use Ethernet protocol and carrier sense multiple access with collision avoidance (i.e., CSMA/CA) for path sharing.",
"The various 802.11x specifications may use phase-shift keying (i.e., PSK) modulation or complementary code keying (i.e., CCK) modulation, for example.",
"As is known in the art, Bluetooth is a telecommunications industry specification that allows e.g., mobile phones, computers, and personal digital assistants to be interconnected using a short-range wireless connection.",
"Client electronic devices 38 , 40 , 42 , 44 may each execute an operating system, examples of which may include but are not limited to Microsoft Windows™, Microsoft Windows CE™, Redhat Linux™, or a custom operating system.",
"The Feed Generation Process: For the following discussion, feed reading process 22 is going to be described for illustrative purposes.",
"However, this is not intended to be a limitation of this disclosure, as other feed reading processes (e.g., feed reading processes 24 , 26 , 28 ) may be equally utilized.",
"Referring also to FIGS. 2 &",
"3 and as discussed above, feed generation process 10 may process 100 a data page (such as a TeamSpace™ page) to be provided to one or more remote devices (e.g., client electronic devices 38 , 40 , 42 , 44 ) via a data feed (e.g., an RSS feed or an ATOM feed).",
"As is known in the art, a TeamSpace may be a web-based collaborative workspace system for managing shared work processes and maintaining shared artifacts in a project that may span months/years.",
"A TeamSpace may cover both synchronous and asynchronous cross-company team activities and may provide a seamless transition between various work modes.",
"Feed reading process 22 may allow user 46 to browse through various sites (e.g. websites and team spaces) so that user 46 may subscribe to one or more web feeds.",
"For example, using feed reading process 22 , user 46 may browse team space 100 (i.e. “Tony's Team Page”).",
"Team space 100 may include menu bar 102 that allows user 46 to select from a plurality of sub pages, such as “Home”, “Discussion”, “Library”, “Calendar”, “Tasks”, “Index”, “Customize”, and “Members.”",
"Team space 100 may include subscription button 104 that allows user 46 to subscribe to web feed 150 .",
"As discussed above, web feeds may be used to distribute information to subscribers and visitors of a website.",
"Accordingly, web feed 150 may be used to distribute information available on team space page 100 .",
"For example, team space page 100 is shown to include three files available for download, namely: Test_Image.",
"gif;",
"Error_Log.",
"txt;",
"and Chicago_Slideshow.",
"PPT.",
"Accordingly, through the use of web feed 150 , user 46 may receive content distributed by e.g. team space page 100 , including but not limited to the three files available for download, namely: Test_Image.",
"gif;",
"Error_Log.",
"txt;",
"and Chicago_Slideshow.",
"PPT.",
"While the content distributor is described above is being team space page 100 , this is for illustrative purposes only and is not intended to be a limitation of this disclosure, as other configurations are possible.",
"For example, the content distributor may be a news website, a blog site, or a social networking website.",
"As discussed above, various feed formats (e.g., RSS &",
"Atom) may be utilized to achieve the desired data distribution.",
"Unfortunately, for certain feed types (e.g., Atom feeds), it is not possible to reconstruct “complex”",
"pages (i.e., pages that include multiple data objects, such as attachments, fields, metadata, etc).",
"Accordingly, as team space page 100 includes three attachments, this is a “complex”",
"page that may be difficult to reconstruct when transmitted using various feed formats.",
"Accordingly and referring also to FIG. 4 , when a user (e.g. user 46 ) selects subscription button 104 , thus indicating that (in this particular example) user 46 wishes to subscribe to a web feed of team space page 100 , feed generation process 10 may process 200 team space page 100 (i.e. the page that is to be provided to the remote devices (e.g. personal computer 38 ) via data feed 150 ) to determine 202 whether team space page 100 includes two or more data objects.",
"In the event that team space page 100 does not include multiple objects, feed generation process 10 may publish 204 a feed of the data included within team space page 100 .",
"However and as discussed above, since team space page 100 includes a plurality of attachments, namely: Test_Image.",
"gif 106 ;",
"Error_Log.",
"txt 108 ;",
"and Chicago_Slideshow.",
"PPT 110 , team space page 100 does indeed include two or more data objects.",
"Accordingly, upon feed generation process 10 determining 202 that team space page 100 includes multiple objects, feed generation process 10 may define 206 a page entry for the data page (i.e. team space page 100 ) and may define 208 an object entry for each of the data objects included within team space page 100 (i.e. Test_Image.",
"gif 106 ;",
"Error_Log.",
"txt 108 ;",
"and Chicago_Slideshow.",
"PPT 110 ).",
"As is known in the art, web feeds (e.g. web feed 150 ) may include a plurality of feed entries.",
"Therefore, when publishing web feed 150 , feed generation process 10 may include, within web feed 150 , the page entry defined 204 for team space page 100 and the object entries defined 206 for Test_Image.",
"gif 106 ;",
"Error_Log.",
"txt 108 ;",
"and Chicago_Slideshow.",
"PPT 110 .",
"For illustrative purposes, web feed 150 is shown to include the four above-described feed entries, namely page entry 152 (which corresponds to team space page 100 ), object entry 154 (which corresponds to Test_Image.",
"gif 106 ), object entry 156 (which corresponds to Error_Log.",
"txt 108 ), and object entry 158 (which corresponds to Chicago_Slideshow.",
"PPT 110 ).",
"When generating web feed 150 , feed generation process 10 may also include additional information 160 , 162 that may be required to e.g. define the feed type, define the beginning of the feed, and define the end of the feed).",
"Page entry 152 may define various aspects of team space page 100 , such as: the title of the page (“Tony's Team Page”);",
"the publication date of the page;",
"and the author of the page.",
"Each of object entries 154 , 156 , 158 may define various aspects of the related data object, such as: the title of the data object;",
"the publication date of the data object;",
"and the author of the data object.",
"When defining 208 the object entries (e.g., object entries 154 , 156 , 158 ), feed generation process 10 may associate each object entry defined within web feed 150 with the related page entry (e.g., page entry 152 ), thus allowing web feed 150 to be properly processed by feed reading process 22 .",
"For example, each page entry (e.g. page entry 152 ) may include a master entry ID.",
"Further, each object entry (e.g. object entries 154 , 156 , 158 ) may include a slave entry ID that is associated with the master entry ID, and the slave entry ID included within each object entry may include at least a portion of the master entry ID.",
"For example and for illustrative purposes only, page entry 152 may include master ID entry 164 (i.e. 0F7F78B411663465852572DB00775018).",
"Further, object entry 154 may include slave entry ID 166 (i.e. 0F7F78B411663465852572DB00775018.1);",
"object entry 156 may include slave entry ID 168 (i.e., 0F7F78B411663465852572DB00775018.2);",
"and object entry 156 may include slave entry ID 170 (i.e., 0F7F78B411663465852572DB00775018.3).",
"In this example, slave entry IDs 166 , 168 , 170 are shown to be identical to master entry ID 164 with the exception that a suffix (e.g. “0.1”, “0.2”, “0.3”, respectively) was added to each of slave entry IDs 166 , 168 , 170 .",
"Accordingly, the “root”",
"portion (i.e. 0F7F78B411663465852572DB00775018) of each of slave entry IDs 166 , 168 , 170 is identical to that of master ID entry 164 (i.e. 0F7F78B411663465852572DB00775018).",
"Accordingly, by using such a master entry ID/slave entry ID nomenclature, feed generation process 10 may associate each object entry (e.g., object entries 154 , 156 , 158 ) defined within web feed 150 with the related page entry (e.g., page entry 152 ).",
"The above-described master entry ID/slave entry ID nomenclature is for illustrative purposes only and is not intended to be a limitation of this disclosure, as other configurations are possible.",
"For example, instead of attaching a suffix to each of slave entry IDs 166 , 168 , 170 , an additional line item may be inserted into each of the corresponding object entries (namely object entries 154 , 156 , 158 ) that defines the associated page entry (namely page entry 152 ).",
"Once web feed 150 is defined, feed generation process 10 and/or syndication application 20 may provide 210 web feed 150 (which includes page entry 152 and object entries 154 , 156 , 158 ) to one or more remote devices (e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 ).",
"When providing web feed 150 (which includes page entry 152 and object entries 154 , 156 , 158 ) to e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 , feed generation process 10 and/or syndication application 20 may publish 212 web feed 150 to the remote devices.",
"Accordingly, feed generation process 10 and/or syndication application 20 may transmit web feed 150 to e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 .",
"Alternatively/additionally, when providing web feed 150 (which includes page entry 152 and object entries 154 , 156 , 158 ) to e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 , feed generation process 10 and/or syndication application 20 may enable availability 214 of web feed 150 to e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 .",
"Accordingly, feed generation process 10 and/or syndication application 20 may allow users of e.g. personal computer 38 , laptop computer 40 , personal digital assistant 42 , notebook computer 44 to download/obtain a copy of web feed 150 (e.g. in a manner similar to that of a podcast).",
"A number of implementations have been described.",
"Nevertheless, it will be understood that various modifications may be made.",
"Accordingly, other implementations are within the scope of the following claims."
] |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for fabricating a semiconductor structure, and more particularly to a method for fabricating a conductive contact with reduced contact resistances.
2. Description of the Related Art
Recently, along with progressive micro-sizing of semiconductor devices, degree of integration has also increased. Accordingly, the dimensions of the diameters of conductive contacts of semiconductor devices have been reduced.
Thus, the fabrication technique for forming a conductive contact in the interlayer insulating film between a conductive region of a semiconductor substrate and an upper wiring level layer over the interlayer insulating film is one of the most important fabrication techniques for semiconductor fabrication today. As the degree of density of integration of integrated circuit devices increases, contact resistances of the conductive contacts formed in the insulating layer is further increased along with the reduction of the dimensions of the diameters of conductive contacts.
Thus, it is necessary to develop a method for fabricating a conductive contact with reduced contact resistances for semiconductor devices of further reduced-sizes.
BRIEF SUMMARY OF THE INVENTION
An exemplary method for fabricating a conductive contact comprises: providing a semiconductor substrate with a gate structure formed thereover and a pair of first conductive regions formed therein in a first region thereof, and a pair of second conductive regions and an isolation element formed therein, and a first dielectric layer and a second dielectric layer thereon in a second region thereof, wherein the pair of first conductive regions are formed in the semiconductor substrate from opposite sides of the gate structure and the isolation element isolates the pair of the second conductive regions from each other; conformably and sequentially forming a third dielectric layer and a fourth dielectric layer over the semiconductor substrate in the first region; forming a pattern mask layer with a first opening therein over the second dielectric layer in the second region, wherein the first opening is substantially located over the isolation element; performing an etching process to etch back the third and fourth dielectric layers in the first region and a portion of the first and second dielectric layers in the second region exposed by the opening in the patterned mask layer, thereby forming a composite spacer on opposite sidewalls of the gate structure in the first region and a second opening in the first and second dielectric layers in the second region, wherein the second opening formed in the first and second dielectric layers exposes a portion of a top surface of the isolation element and portions of a top surface of the pair of second conductive regions; removing the patterned mask layer; performing an epitaxy process and forming a first conductive semiconductor layer over the pair of the first conductive regions and a second conductive semiconductor layer over the top surface of the isolation element and portions of the top surface of the pair of second conductive regions exposed by the second opening; blanketly forming a fifth dielectric layer over the semiconductor substrate in the first and second regions; forming a third opening in the fifth dielectric layer in the second region, exposing a top surface of the second conductive semiconductor; and forming a conductive layer in the third opening, overlying the second conductive semiconductor layer and filling the fifth opening.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
FIGS. 1-6 are schematic diagrams showing a method for fabricating a conductive contact according to an embodiment of the invention; and
FIGS. 7-12 are schematic diagrams showing a method for fabricating a conductive contact according to another embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
FIGS. 1-6 are schematic diagrams showing an exemplary method for fabricating a conductive contact, wherein FIGS. 1-5 show schematic cross sections and FIG. 6 shows a schematic top view of the method. Herein, the exemplary method is a method known by the inventors and is used as a comparative example to comment on the problems found by the inventors, but is not used to restrict the scope of the invention.
In FIG. 1 , a semiconductor substrate 100 such as a p-type silicon substrate is first provided. As shown in FIG. 1 , two individual regions A and B are defined over the semiconductor substrate 100 to accommodate various devices (not shown). In one embodiment, the region A may function as an array region for accommodating memory cells of a memory device (not shown) and the region B may function as a periphery region for accommodating periphery circuits of a memory device (not shown). The semiconductor substrate 100 in the region A is provided with a plurality of conductive regions 104 and an isolation element 102 therein, and two dielectric layers 106 and 108 sequentially formed thereover. The semiconductor substrate 100 in the region B is provided with a gate structure G thereover and two conductive regions 116 formed therein, and the conductive regions 116 are adjacent to opposite sides of the gate structure G. In one embodiment, the isolation element 102 in the region A is a shallow trench isolation (STI) but is not limited thereto. The isolation element 102 isolates the conductive regions 104 from each other. In one embodiment, the conductive regions 104 can be, for example, n-type doped regions which may both function as source or drain regions of a transistor (not shown) for a memory cell of a memory device such as a dynamic random access memory (DRAM) device. The dielectric layer 106 may comprise silicon oxide and has a thickness of about 1000-2000 Å, and the dielectric layer 108 may comprise silicon nitride and has a thickness of about 100-500 Å. The gate structure G may comprise a gate dielectric layer 110 , a gate electrode 112 , and a mask layer 114 sequentially formed over the semiconductor substrate 100 , and the conductive regions 116 formed in the semiconductor substrate 100 in the region B can be, for example, n-type doped regions which may function as source/drain regions. In one embodiment, the gate dielectric layer 110 may comprise silicon oxide or high-k dielectrics, the gate electrode 112 may comprise doped polysilicon, metal, or combinations thereof, and the mask layer 114 may comprise silicon nitride.
In FIG. 2 , a dielectric layer 118 of a thickness of about 50-200 Å and a dielectric layer 120 of a thickness of about 100-300 Å are sequentially formed over the semiconductor substrate 100 to conformably cover the gate structure G in the region B and a top surface of the dielectric layer 108 in the region A. In one embodiment, the dielectric layer 118 may comprise silicon nitride and the dielectric layer 120 may comprise silicon oxide. Next, an etching process 122 such as a dry etching process is performed to etch back the dielectric layers 120 and 118 , thereby forming a composite spacer 124 on opposite sidewalls of the gate structure G in the region B and entirely removing the dielectric layers 120 and 118 in the regions A, as shown in FIG. 3 .
In FIG. 3 , each of the composite spacers 124 comprises the patterned dielectric layers 118 a and 120 a and partially covers a portion of the conductive regions 116 adjacent to the gate structure G. Next, an epitaxy process 126 is performed to form a conductive semiconductor layer 128 on the conductive regions 116 in the region B. During the epitaxy process 126 , the top surface of the semiconductor substrate 100 in the region A is covered by the dielectric layers 106 and 108 such that the conductive semiconductor layer 128 will not be formed over the semiconductor substrate 100 in the region A. The epitaxy process 126 can be, for example, a chemical vapor deposition (CVD) method performed under a temperature of about 850° C., using SiH 2 Cl 2 , HCl and H 2 as reacting gases. In the epitaxy process 126 , the formed conductive semiconductor materials may comprise semiconductor materials such as silicon in-situ doped with conductive dopants such as arsenic (As) and phosphorus (P) or other elements. The conductive semiconductor layer 128 formed over the exposed surface of the conductive regions 116 adjacent to the gate structure G may function as a raised source/drain region for improving device performance of a transistor comprised thereof.
In FIG. 4 , a deposition process 130 such as a spin-on process is performed to blanketly form a dielectric layer 132 over the semiconductor substrate 100 in the regions A and B, covering the gate structure G, the composite spacers 124 , and the conductive semiconductor layer 128 . The dielectric layer 132 can be, for example, spin-on dielectric materials such as polysilazane such that the dielectric layer 132 can be formed with a planar top surface after formation thereof.
In FIG. 5 , an etching process 134 is performed to form an opening 132 through the dielectric layers 132 , 108 and 106 in the region A. The opening 132 exposes a top surface of the isolation element 102 and portions of a top surface of the conductive regions 104 adjacent to the isolation element 102 . Herein, the opening 136 functions as a contact hole and is formed with an aspect ratio (H:W) of, for example, 1:1-5:1. Next, a conductive material such as metal or doped polysilicon is deposited over the dielectric layer 132 and entirely fills the opening 136 , and a portion of the conductive material above a top surface of the dielectric layer 132 is then removed by a planarization process (not shown) such as a chemical mechanical polishing (CMP) process, thereby leaving a conductive contact 138 in the opening 136 to physically and electrically connect the conductive regions 104 with conductive element (not shown) which is later formed thereover, for example, a conductive wire, formed over the dielectric layer 132 . FIG. 6 shows a top view of the structure shown in FIG. 5 , and the structure shown in FIG. 5 shows a cross section taken along the line 5 - 5 of FIG. 6 .
However, as shown in the exemplary structure as illustrated in FIGS. 5-6 , since the dimension such as a width or a diameter W of the opening 136 will be further decreased with shrinkage of the semiconductor device comprising the exemplary structure as illustrated in FIGS. 5-6 , the aspect ratio of the opening 136 will further increase such that it becomes problematic to fill the conductive material of the conductive contact 138 in the opening 136 . Thus, voids or seams may be formed in the conductive contact 138 , thereby causing an open circuit between the conductive regions 104 and conductive elements (not shown) which are later formed thereover. In addition, a hetero-junction between the conductive regions 104 and the conductive contact 138 is small since the conductive contact 138 only partially covers a portion of a top surface thereof. Thus, the contact resistance of the conductive contact 138 is increased as a surface area of the hetero-junction between the conductive regions 104 and the conductive contact 138 is reduced.
Thus, an improved method for fabricating a conductive contact to address the above issues is needed. FIGS. 7-12 are schematic diagrams showing an exemplary method for fabricating a conductive contact mitigating the above issues, wherein FIGS. 7-11 show schematic cross sections and FIG. 12 shows a schematic top view of the exemplary method.
In FIG. 7 , a semiconductor substrate 200 such as a p-type silicon substrate is first provided. As shown in FIG. 7 , two individual regions A and B are defined over the semiconductor substrate 200 for accommodating various devices (not shown). In one embodiment, the region A may function as an array region for accommodating memory cells of a memory device (not shown) and the region B may function as a periphery region for accommodating periphery circuits of a memory device (not shown). The semiconductor substrate 200 in the region A is provided with a plurality of conductive regions 204 , an isolation element 202 therein, and two dielectric layers 206 and 208 sequentially formed thereover. The semiconductor substrate 200 in the region B is provided with a gate structure G formed thereover and two conductive regions 216 formed in the semiconductor substrate 200 which is respectively adjacent to opposite sides of the gate structure G. In one embodiment, the isolation element 202 in the region A is a shallow trench isolation (STI) but is not limited thereto. The isolation element 202 isolates the conductive regions 204 from each other. In one embodiment, the conductive regions 204 can be, for example, n-type doped regions which may both function as source or drain regions of a transistor (not shown) for a memory cell of a memory device such as a dynamic random access memory (DRAM) device. The dielectric layer 206 may comprise silicon oxide and has a thickness of about 1000-2000 Å, and the dielectric layer 208 may comprise silicon nitride and has a thickness of about 100-500 Å. The gate structure G may comprise a gate dielectric layer 210 , a gate electrode 212 , and a mask layer 214 sequentially formed over the semiconductor substrate 200 , and the conductive regions 216 formed in the semiconductor substrate 200 in the region B can be, for example, n-type doped regions which may function as source or drain regions. In one embodiment, the gate dielectric layer 210 may comprise silicon oxide or high-k dielectrics, the gate electrode 212 may comprise doped polysilicon, metal, or combinations thereof, and the mask layer may comprise silicon nitride. Next, a dielectric layer 218 of a thickness of about 50-200 Å and a dielectric layer 220 of a thickness of about 100-300 Å are sequentially formed over the semiconductor substrate 200 only in the region B to conformably cover the gate structure G and the semiconductor substrate 200 in the region B. In one embodiment, the dielectric layer 218 may comprise silicon nitride and the dielectric layer 220 may comprise silicon oxide. Next, a pattern mask layer 222 with an opening 224 therein is formed over the semiconductor substrate 200 only in the region A, and the opening 224 is substantially located over the isolation element 202 and exposes a portion of the dielectric layers 208 and 206 formed over the isolation element 202 .
In FIG. 8 , an etching process 226 such as a dry etching process is performed to etch back the dielectric layers 220 and 218 in the region B and etch through the dielectric layers 208 and 206 in the region A, thereby forming a composite spacer 228 on opposite sidewalls of the gate structure G in the region B and forming an opening 230 in the dielectric layers 220 and 218 in the region A. The opening 230 exposes a top surface of the isolation element 202 and portions of a top surface of the conductive regions 204 adjacent to the isolation element 202 . As shown in FIG. 8 , each of the composite spacers 228 comprises the patterned dielectric layers 218 a and 220 a and partially covers a portion of the conductive regions 216 adjacent to the gate structure G.
In FIG. 9 , the patterned mask layer 222 formed in the region A is first removed and an epitaxy process 232 is performed to form a conductive semiconductor layer 234 on the conductive regions 216 in the region B and a conductive semiconductor layer 236 on the top surfaces of the isolation element 202 and portions of the conductive region 204 adjacent to the isolation element 202 . The epitaxy process 232 can be, for example, a chemical vapor deposition (CVD) method performed under a temperature of about 850° C., using SiH 2 Cl 2 , HCl and H 2 as reacting gases. In the epitaxy process 232 , the formed semiconductor material of the conductive semiconductor layers 234 and 236 may comprise semiconductor materials such as silicon in-situ doped with conductive dopants such as arsenic (As), phosphorus (P) or other elements. The conductive semiconductor layer 234 formed over the exposed surface of the conductive regions 216 adjacent to the gate structure G may have a thickness of about 100-400 Å, functioning as a raised source/drain region for improving device performance of a transistor comprised thereof. The conductive semiconductor layer 236 formed on the top surfaces of the isolation element 202 and portions of the conductive region 204 adjacent to the isolation element 202 may have a thickness of about 100-400 Å and functions as a portion of a conductive contact to reduce a contact resistance thereof.
In FIG. 10 , a deposition process 238 such as a spin-on process is performed to blanketly form a dielectric layer 240 over the semiconductor substrate 200 in the regions A and B, covering the gate structure G, the composite spacers 228 , the dielectric layer 208 , and the conductive semiconductor layers 234 and 236 . The dielectric layer 240 can be, for example, spin-on dielectric materials such as polysilazane such that the dielectric layer 240 can be formed with a planar top surface after formation thereof.
In FIG. 11 , an etching process 242 is performed to form an opening 244 through the dielectric layer 240 in the region A, and the opening 240 again expose a top surface of the conductive semiconductor layer 236 formed over portions of the top surface of the conductive regions 204 adjacent to the isolation element 202 . Herein, the opening 244 functions as a contact hole and is formed with an aspect ratio (H:W) of, for example, 1:1-4:1, which is reduced when compared with the aspect ratio of the contact hole 136 shown in FIG. 5 . Next, a conductive material such as metal or doped polysilicon is then deposited over the dielectric layer 240 and entirely fills the opening 244 , and a portion of the conductive material above a top surface of the dielectric layer 240 is then removed by a planarization process (not shown) such as a chemical mechanical polishing (CMP) process, thereby leaving a conductive layer 246 in the opening 244 . A combination of the conductive layer 246 and the conductive semiconductor layer 236 functions as a conductive contact for physically and electrically connect the conductive regions 204 with conductive element (not shown) which is later formed thereover, for example, a conductive wire, formed over the dielectric layer 240 . FIG. 12 shows a top view of the structure shown in FIG. 11 , and the structure shown in FIG. 11 shows a cross section taken along a line 11 - 11 in FIG. 12 .
In the exemplary structure as disclosed in FIGS. 11-12 , due to formation of the conductive semiconductor layer 236 formed during formation of the conductive semiconductor layers 238 in the region B, the aspect ratio of the opening 244 can be decreased such that the conductive material of the conductive layer 246 is ensured to entirely be filled into the opening 244 . This is advantageous when a dimension such as a width or a diameter W of the opening 244 is further decreased with the shrinkage of a semiconductor device having the opening 244 . Thus, no voids or seams will be formed in the conductive contact and the open circuit issue between the conductive regions 204 and conductive elements (not shown) which are later formed thereover, will not occur. In addition, a homo-junction is formed between the conductive semiconductor layer 236 and the conductive regions 204 , and the conductive layer 246 and the conductive semiconductor layer 236 have a hetero-junction therebetween which is much greater than the hetero-junction formed between the conductive contact 138 and the conductive regions 104 as shown in FIG. 5 , such that a contact resistance of the conductive contact comprising the conductive layer 246 and the conductive semiconductor layer 236 is reduced, despite shrinkage of the semiconductor device having the conductive contact. Moreover, since the conductive semiconductor layer 236 of the conductive contact can be simultaneously formed during the epitaxy process for forming the conductive semiconductor layers 234 in the region B, thermal budget for forming the conductive regions 204 formed in the region A and the conductive regions 216 formed in the region B can be precisely controlled.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. | A method for fabricating a conductive contact is provided, including: providing a semiconductor substrate with a gate structure and a pair of first conductive regions in a first region, and a pair of second conductive regions and an isolation element in the second region, and a first dielectric layer and a second dielectric layer thereon; forming a third dielectric layer and a fourth dielectric layer over the semiconductor substrate in the first region; forming a pattern mask layer with a first opening over the second dielectric layer in the second region; performing an etching process to the third and fourth dielectric layers in the first region and a portion of the first and second dielectric layers in the second region exposed by the first opening; removing the patterned mask layer; forming a first conductive semiconductor layer over the first conductive regions and a second conductive semiconductor layer over the isolation element and portions of the top surface of the second conductive regions; forming a fifth dielectric layer over the semiconductor substrate; forming a third opening in the fifth dielectric layer in the second region; and forming a conductive layer in the third opening. | Provide a concise summary of the essential information conveyed in the context. | [
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present invention relates to a method for fabricating a semiconductor structure, and more particularly to a method for fabricating a conductive contact with reduced contact resistances.",
"Description of the Related Art Recently, along with progressive micro-sizing of semiconductor devices, degree of integration has also increased.",
"Accordingly, the dimensions of the diameters of conductive contacts of semiconductor devices have been reduced.",
"Thus, the fabrication technique for forming a conductive contact in the interlayer insulating film between a conductive region of a semiconductor substrate and an upper wiring level layer over the interlayer insulating film is one of the most important fabrication techniques for semiconductor fabrication today.",
"As the degree of density of integration of integrated circuit devices increases, contact resistances of the conductive contacts formed in the insulating layer is further increased along with the reduction of the dimensions of the diameters of conductive contacts.",
"Thus, it is necessary to develop a method for fabricating a conductive contact with reduced contact resistances for semiconductor devices of further reduced-sizes.",
"BRIEF SUMMARY OF THE INVENTION An exemplary method for fabricating a conductive contact comprises: providing a semiconductor substrate with a gate structure formed thereover and a pair of first conductive regions formed therein in a first region thereof, and a pair of second conductive regions and an isolation element formed therein, and a first dielectric layer and a second dielectric layer thereon in a second region thereof, wherein the pair of first conductive regions are formed in the semiconductor substrate from opposite sides of the gate structure and the isolation element isolates the pair of the second conductive regions from each other;",
"conformably and sequentially forming a third dielectric layer and a fourth dielectric layer over the semiconductor substrate in the first region;",
"forming a pattern mask layer with a first opening therein over the second dielectric layer in the second region, wherein the first opening is substantially located over the isolation element;",
"performing an etching process to etch back the third and fourth dielectric layers in the first region and a portion of the first and second dielectric layers in the second region exposed by the opening in the patterned mask layer, thereby forming a composite spacer on opposite sidewalls of the gate structure in the first region and a second opening in the first and second dielectric layers in the second region, wherein the second opening formed in the first and second dielectric layers exposes a portion of a top surface of the isolation element and portions of a top surface of the pair of second conductive regions;",
"removing the patterned mask layer;",
"performing an epitaxy process and forming a first conductive semiconductor layer over the pair of the first conductive regions and a second conductive semiconductor layer over the top surface of the isolation element and portions of the top surface of the pair of second conductive regions exposed by the second opening;",
"blanketly forming a fifth dielectric layer over the semiconductor substrate in the first and second regions;",
"forming a third opening in the fifth dielectric layer in the second region, exposing a top surface of the second conductive semiconductor;",
"and forming a conductive layer in the third opening, overlying the second conductive semiconductor layer and filling the fifth opening.",
"A detailed description is given in the following embodiments with reference to the accompanying drawings.",
"BRIEF DESCRIPTION OF THE DRAWINGS The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: FIGS. 1-6 are schematic diagrams showing a method for fabricating a conductive contact according to an embodiment of the invention;",
"and FIGS. 7-12 are schematic diagrams showing a method for fabricating a conductive contact according to another embodiment of the invention.",
"DETAILED DESCRIPTION OF THE INVENTION The following description is of the best-contemplated mode of carrying out the invention.",
"This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense.",
"The scope of the invention is best determined by reference to the appended claims.",
"FIGS. 1-6 are schematic diagrams showing an exemplary method for fabricating a conductive contact, wherein FIGS. 1-5 show schematic cross sections and FIG. 6 shows a schematic top view of the method.",
"Herein, the exemplary method is a method known by the inventors and is used as a comparative example to comment on the problems found by the inventors, but is not used to restrict the scope of the invention.",
"In FIG. 1 , a semiconductor substrate 100 such as a p-type silicon substrate is first provided.",
"As shown in FIG. 1 , two individual regions A and B are defined over the semiconductor substrate 100 to accommodate various devices (not shown).",
"In one embodiment, the region A may function as an array region for accommodating memory cells of a memory device (not shown) and the region B may function as a periphery region for accommodating periphery circuits of a memory device (not shown).",
"The semiconductor substrate 100 in the region A is provided with a plurality of conductive regions 104 and an isolation element 102 therein, and two dielectric layers 106 and 108 sequentially formed thereover.",
"The semiconductor substrate 100 in the region B is provided with a gate structure G thereover and two conductive regions 116 formed therein, and the conductive regions 116 are adjacent to opposite sides of the gate structure G. In one embodiment, the isolation element 102 in the region A is a shallow trench isolation (STI) but is not limited thereto.",
"The isolation element 102 isolates the conductive regions 104 from each other.",
"In one embodiment, the conductive regions 104 can be, for example, n-type doped regions which may both function as source or drain regions of a transistor (not shown) for a memory cell of a memory device such as a dynamic random access memory (DRAM) device.",
"The dielectric layer 106 may comprise silicon oxide and has a thickness of about 1000-2000 Å, and the dielectric layer 108 may comprise silicon nitride and has a thickness of about 100-500 Å.",
"The gate structure G may comprise a gate dielectric layer 110 , a gate electrode 112 , and a mask layer 114 sequentially formed over the semiconductor substrate 100 , and the conductive regions 116 formed in the semiconductor substrate 100 in the region B can be, for example, n-type doped regions which may function as source/drain regions.",
"In one embodiment, the gate dielectric layer 110 may comprise silicon oxide or high-k dielectrics, the gate electrode 112 may comprise doped polysilicon, metal, or combinations thereof, and the mask layer 114 may comprise silicon nitride.",
"In FIG. 2 , a dielectric layer 118 of a thickness of about 50-200 Å and a dielectric layer 120 of a thickness of about 100-300 Å are sequentially formed over the semiconductor substrate 100 to conformably cover the gate structure G in the region B and a top surface of the dielectric layer 108 in the region A. In one embodiment, the dielectric layer 118 may comprise silicon nitride and the dielectric layer 120 may comprise silicon oxide.",
"Next, an etching process 122 such as a dry etching process is performed to etch back the dielectric layers 120 and 118 , thereby forming a composite spacer 124 on opposite sidewalls of the gate structure G in the region B and entirely removing the dielectric layers 120 and 118 in the regions A, as shown in FIG. 3 .",
"In FIG. 3 , each of the composite spacers 124 comprises the patterned dielectric layers 118 a and 120 a and partially covers a portion of the conductive regions 116 adjacent to the gate structure G. Next, an epitaxy process 126 is performed to form a conductive semiconductor layer 128 on the conductive regions 116 in the region B. During the epitaxy process 126 , the top surface of the semiconductor substrate 100 in the region A is covered by the dielectric layers 106 and 108 such that the conductive semiconductor layer 128 will not be formed over the semiconductor substrate 100 in the region A. The epitaxy process 126 can be, for example, a chemical vapor deposition (CVD) method performed under a temperature of about 850° C., using SiH 2 Cl 2 , HCl and H 2 as reacting gases.",
"In the epitaxy process 126 , the formed conductive semiconductor materials may comprise semiconductor materials such as silicon in-situ doped with conductive dopants such as arsenic (As) and phosphorus (P) or other elements.",
"The conductive semiconductor layer 128 formed over the exposed surface of the conductive regions 116 adjacent to the gate structure G may function as a raised source/drain region for improving device performance of a transistor comprised thereof.",
"In FIG. 4 , a deposition process 130 such as a spin-on process is performed to blanketly form a dielectric layer 132 over the semiconductor substrate 100 in the regions A and B, covering the gate structure G, the composite spacers 124 , and the conductive semiconductor layer 128 .",
"The dielectric layer 132 can be, for example, spin-on dielectric materials such as polysilazane such that the dielectric layer 132 can be formed with a planar top surface after formation thereof.",
"In FIG. 5 , an etching process 134 is performed to form an opening 132 through the dielectric layers 132 , 108 and 106 in the region A. The opening 132 exposes a top surface of the isolation element 102 and portions of a top surface of the conductive regions 104 adjacent to the isolation element 102 .",
"Herein, the opening 136 functions as a contact hole and is formed with an aspect ratio (H:W) of, for example, 1:1-5:1.",
"Next, a conductive material such as metal or doped polysilicon is deposited over the dielectric layer 132 and entirely fills the opening 136 , and a portion of the conductive material above a top surface of the dielectric layer 132 is then removed by a planarization process (not shown) such as a chemical mechanical polishing (CMP) process, thereby leaving a conductive contact 138 in the opening 136 to physically and electrically connect the conductive regions 104 with conductive element (not shown) which is later formed thereover, for example, a conductive wire, formed over the dielectric layer 132 .",
"FIG. 6 shows a top view of the structure shown in FIG. 5 , and the structure shown in FIG. 5 shows a cross section taken along the line 5 - 5 of FIG. 6 .",
"However, as shown in the exemplary structure as illustrated in FIGS. 5-6 , since the dimension such as a width or a diameter W of the opening 136 will be further decreased with shrinkage of the semiconductor device comprising the exemplary structure as illustrated in FIGS. 5-6 , the aspect ratio of the opening 136 will further increase such that it becomes problematic to fill the conductive material of the conductive contact 138 in the opening 136 .",
"Thus, voids or seams may be formed in the conductive contact 138 , thereby causing an open circuit between the conductive regions 104 and conductive elements (not shown) which are later formed thereover.",
"In addition, a hetero-junction between the conductive regions 104 and the conductive contact 138 is small since the conductive contact 138 only partially covers a portion of a top surface thereof.",
"Thus, the contact resistance of the conductive contact 138 is increased as a surface area of the hetero-junction between the conductive regions 104 and the conductive contact 138 is reduced.",
"Thus, an improved method for fabricating a conductive contact to address the above issues is needed.",
"FIGS. 7-12 are schematic diagrams showing an exemplary method for fabricating a conductive contact mitigating the above issues, wherein FIGS. 7-11 show schematic cross sections and FIG. 12 shows a schematic top view of the exemplary method.",
"In FIG. 7 , a semiconductor substrate 200 such as a p-type silicon substrate is first provided.",
"As shown in FIG. 7 , two individual regions A and B are defined over the semiconductor substrate 200 for accommodating various devices (not shown).",
"In one embodiment, the region A may function as an array region for accommodating memory cells of a memory device (not shown) and the region B may function as a periphery region for accommodating periphery circuits of a memory device (not shown).",
"The semiconductor substrate 200 in the region A is provided with a plurality of conductive regions 204 , an isolation element 202 therein, and two dielectric layers 206 and 208 sequentially formed thereover.",
"The semiconductor substrate 200 in the region B is provided with a gate structure G formed thereover and two conductive regions 216 formed in the semiconductor substrate 200 which is respectively adjacent to opposite sides of the gate structure G. In one embodiment, the isolation element 202 in the region A is a shallow trench isolation (STI) but is not limited thereto.",
"The isolation element 202 isolates the conductive regions 204 from each other.",
"In one embodiment, the conductive regions 204 can be, for example, n-type doped regions which may both function as source or drain regions of a transistor (not shown) for a memory cell of a memory device such as a dynamic random access memory (DRAM) device.",
"The dielectric layer 206 may comprise silicon oxide and has a thickness of about 1000-2000 Å, and the dielectric layer 208 may comprise silicon nitride and has a thickness of about 100-500 Å.",
"The gate structure G may comprise a gate dielectric layer 210 , a gate electrode 212 , and a mask layer 214 sequentially formed over the semiconductor substrate 200 , and the conductive regions 216 formed in the semiconductor substrate 200 in the region B can be, for example, n-type doped regions which may function as source or drain regions.",
"In one embodiment, the gate dielectric layer 210 may comprise silicon oxide or high-k dielectrics, the gate electrode 212 may comprise doped polysilicon, metal, or combinations thereof, and the mask layer may comprise silicon nitride.",
"Next, a dielectric layer 218 of a thickness of about 50-200 Å and a dielectric layer 220 of a thickness of about 100-300 Å are sequentially formed over the semiconductor substrate 200 only in the region B to conformably cover the gate structure G and the semiconductor substrate 200 in the region B. In one embodiment, the dielectric layer 218 may comprise silicon nitride and the dielectric layer 220 may comprise silicon oxide.",
"Next, a pattern mask layer 222 with an opening 224 therein is formed over the semiconductor substrate 200 only in the region A, and the opening 224 is substantially located over the isolation element 202 and exposes a portion of the dielectric layers 208 and 206 formed over the isolation element 202 .",
"In FIG. 8 , an etching process 226 such as a dry etching process is performed to etch back the dielectric layers 220 and 218 in the region B and etch through the dielectric layers 208 and 206 in the region A, thereby forming a composite spacer 228 on opposite sidewalls of the gate structure G in the region B and forming an opening 230 in the dielectric layers 220 and 218 in the region A. The opening 230 exposes a top surface of the isolation element 202 and portions of a top surface of the conductive regions 204 adjacent to the isolation element 202 .",
"As shown in FIG. 8 , each of the composite spacers 228 comprises the patterned dielectric layers 218 a and 220 a and partially covers a portion of the conductive regions 216 adjacent to the gate structure G. In FIG. 9 , the patterned mask layer 222 formed in the region A is first removed and an epitaxy process 232 is performed to form a conductive semiconductor layer 234 on the conductive regions 216 in the region B and a conductive semiconductor layer 236 on the top surfaces of the isolation element 202 and portions of the conductive region 204 adjacent to the isolation element 202 .",
"The epitaxy process 232 can be, for example, a chemical vapor deposition (CVD) method performed under a temperature of about 850° C., using SiH 2 Cl 2 , HCl and H 2 as reacting gases.",
"In the epitaxy process 232 , the formed semiconductor material of the conductive semiconductor layers 234 and 236 may comprise semiconductor materials such as silicon in-situ doped with conductive dopants such as arsenic (As), phosphorus (P) or other elements.",
"The conductive semiconductor layer 234 formed over the exposed surface of the conductive regions 216 adjacent to the gate structure G may have a thickness of about 100-400 Å, functioning as a raised source/drain region for improving device performance of a transistor comprised thereof.",
"The conductive semiconductor layer 236 formed on the top surfaces of the isolation element 202 and portions of the conductive region 204 adjacent to the isolation element 202 may have a thickness of about 100-400 Å and functions as a portion of a conductive contact to reduce a contact resistance thereof.",
"In FIG. 10 , a deposition process 238 such as a spin-on process is performed to blanketly form a dielectric layer 240 over the semiconductor substrate 200 in the regions A and B, covering the gate structure G, the composite spacers 228 , the dielectric layer 208 , and the conductive semiconductor layers 234 and 236 .",
"The dielectric layer 240 can be, for example, spin-on dielectric materials such as polysilazane such that the dielectric layer 240 can be formed with a planar top surface after formation thereof.",
"In FIG. 11 , an etching process 242 is performed to form an opening 244 through the dielectric layer 240 in the region A, and the opening 240 again expose a top surface of the conductive semiconductor layer 236 formed over portions of the top surface of the conductive regions 204 adjacent to the isolation element 202 .",
"Herein, the opening 244 functions as a contact hole and is formed with an aspect ratio (H:W) of, for example, 1:1-4:1, which is reduced when compared with the aspect ratio of the contact hole 136 shown in FIG. 5 .",
"Next, a conductive material such as metal or doped polysilicon is then deposited over the dielectric layer 240 and entirely fills the opening 244 , and a portion of the conductive material above a top surface of the dielectric layer 240 is then removed by a planarization process (not shown) such as a chemical mechanical polishing (CMP) process, thereby leaving a conductive layer 246 in the opening 244 .",
"A combination of the conductive layer 246 and the conductive semiconductor layer 236 functions as a conductive contact for physically and electrically connect the conductive regions 204 with conductive element (not shown) which is later formed thereover, for example, a conductive wire, formed over the dielectric layer 240 .",
"FIG. 12 shows a top view of the structure shown in FIG. 11 , and the structure shown in FIG. 11 shows a cross section taken along a line 11 - 11 in FIG. 12 .",
"In the exemplary structure as disclosed in FIGS. 11-12 , due to formation of the conductive semiconductor layer 236 formed during formation of the conductive semiconductor layers 238 in the region B, the aspect ratio of the opening 244 can be decreased such that the conductive material of the conductive layer 246 is ensured to entirely be filled into the opening 244 .",
"This is advantageous when a dimension such as a width or a diameter W of the opening 244 is further decreased with the shrinkage of a semiconductor device having the opening 244 .",
"Thus, no voids or seams will be formed in the conductive contact and the open circuit issue between the conductive regions 204 and conductive elements (not shown) which are later formed thereover, will not occur.",
"In addition, a homo-junction is formed between the conductive semiconductor layer 236 and the conductive regions 204 , and the conductive layer 246 and the conductive semiconductor layer 236 have a hetero-junction therebetween which is much greater than the hetero-junction formed between the conductive contact 138 and the conductive regions 104 as shown in FIG. 5 , such that a contact resistance of the conductive contact comprising the conductive layer 246 and the conductive semiconductor layer 236 is reduced, despite shrinkage of the semiconductor device having the conductive contact.",
"Moreover, since the conductive semiconductor layer 236 of the conductive contact can be simultaneously formed during the epitaxy process for forming the conductive semiconductor layers 234 in the region B, thermal budget for forming the conductive regions 204 formed in the region A and the conductive regions 216 formed in the region B can be precisely controlled.",
"While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments.",
"To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art).",
"Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements."
] |
FIELD OF THE INVENTION
[0001] The present invention is directed to the medical use of ultrasound acoustic energy for imaging, doppler based flow measurement, and therapy. In particular, the present invention pertains to the use of adhesive, acoustic self-coupling hydrogels to couple sound between ultrasound transducers and protective sheaths or covers.
BACKGROUND OF THE INVENTION
[0002] Ultrasound, as used for medical applications, utilizes high frequencies, typically between 1 and 30 MHz for imaging and flow measurements and between 0.050 and 1.00 MHz for therapy, all of which are poorly transmitted by air and require a medium similar in acoustic properties to tissue, commonly a thick fluid, gel or solid membrane, which displaces air and fills contours between the “eye” or transducer of an ultrasound instrument (such as a probe or scanhead), which converts energy between electrical and acoustic, and the body or object into which the sound is being directed. This medium, by nature of its physical and acoustic properties, serves as an ultrasound acoustic transmission “coupler” between the object of interest and the electronic transducer, thereby acoustically joining the two, so that the sound based information developed can freely pass back and forth between the body and the electronics. Because of the “coupling” effect, this media is commonly referred to as an ultrasound couplant, ultrasound transmission media or acoustic transmission media.
[0003] Hydrophilic membranes as coupling media is disclosed, for example, in U.S. Pat. No. 6,039,694 to Larson, et al., which teaches the use of hydrogel films composed of block co-polymers of polyurethane and polyacrylonitrile. The patent discloses application of these materials for ultrasound scanning in the form of shape-conforming films produced by dipping methods, flat membranes that can be stretched over the active surface of an ultrasound probe, scanning through a membrane that is placed in direct contact with skin, and imaging through a latex or other polymeric protective probe cover with such a membrane covering the active area of the transducer and portions of the transducer body. These self-coupling hydrogel films eliminate the requirement for gels and other liquid couplants, and can provide a microbial barrier between the patient and ultrasound probe.
[0004] However, by virtue of the composition and mechanical properties, use of films such as those of U.S. Pat. No. 6,039,694 is limited. The films are slippery and lack adhesive characteristics. Such characteristics, while desirable as a scanning surface, tend to allow the membrane to slip off non-horizontal surfaces and slide with the ultrasound probe as it is moved over the surface of the membrane. While the films of U.S. Pat. No. 6,039,694 have sufficient mechanical strength to permit conformal fit by stretching the film over the active face of an ultrasound probe, the absence of adhesive characteristics requires that the membrane be secured to the probe by some mechanical means such as a rubber band or strap. U.S. Pat. No. 5,522,878 to Montecalvo et al. describes a solid, multipurpose, flexible, ultrasonic, biomedical couplant hydrogel in sheet form to facilitate transfer of ultrasound energy to and from a patient. Also described is a method of attaching the sheet to skin to hold the couplant gel in place during an exam, which constitutes a band of pressure sensitive adhesive bonded to plastic foam, such as foamed rubber, that is located along the outer perimeter of the sheet. The hydrogel sheet so described is not adhesive in and of itself, but depends on an unreliable potential that sufficient perspiration will be present to make the gel somewhat tacky in instances where the chemical composition is such that addition of moisture to the hydrogel will result in some degree of tack. The adhesive border, so described, is not acoustic self-coupling, therefore restricting ultrasound scanning to areas exclusive of those covered with adhesive covered foam.
[0005] U.S. Pat. No. 5,782,767 to Pretlow, III, describes a pad assembly for coupling ultrasound from a transducer probe into the human body, wherein a humectant, such as glycerin in combination with water, creates sufficient surface tension for a pad containing a mixture of water and a humectant, such as glycerin, to remain attached to the probe face by the weak forces of surface tension when the pad is extracted from the storage container and placed on skin. Since general scanning procedures normally require large volumes of couplant materials, and the transducer is moved over large areas, such as is done in fetal scanning, the device of U.S. Pat. No. 5,782,767 is limited to single site applications, such as is disclosed by Pretlow for monitoring bladder fullness, rather than as a device for general ultrasound scanning procedures, where its design for such use would not be practical. Use of this device for general scanning would rapidly deplete the glycerin and water mixture, and since the acoustic coupling and the weak forces of surface tension rely upon the presence of this mixture of liquids rather than an engineered adhesive, such general use would to a high degree lead to probable loss of acoustic coupling and separation of the couplant pad from the transducer face.
[0006] U.S. Pat. No. 5,394,877 to Orr et al. describes a contact medium structure attachable to externally applied medical diagnostic devices for providing self-adherence of a medical device to the skin of a patient thereby eliminating the need for retaining belts or similar means. A contact medium is described that is inherently adhesive, hydrophilic, skin compatible, ultrasonic compatible and pressure sensitive to facilitate self-adhesion of the medical device to the patient's skin. The device of Orr et al. discloses use as an ultrasound conductive medium, however such device provides only for the attachment of one side the adhesive membrane to the skin of a patient and the opposite adhesive side to a medical device such as a transducer for monitoring purposes, and as such, is limited to use on one site once properly placed. The design of the device of Orr et al. restricts use of medical devices to one area of the body and prevents free gliding motions of a medical device, such as an ultrasound transducer, over the body of a patient, as is necessary for medical imaging procedures. For example, ultrasound imaging over large external areas or imaging from within the body of a patient is inconsistent with its stated use or structural design.
[0007] The formulation, manufacture and use of adhesive hydrogels for products that form an interface with skin and tissue Is known to the artisan as is the formulation, preparation and use of adhesive hydrophilic compounds for wound treatment and electrically conductive devices. Adhesive hydrogels are commercially available from producers including 3M Corporation, Ludlow Technical Products and Lectec Corporation. For example, Ludlow Technical Products produces UV cured electrically conductive gels designated Series RG 63B, and E-Beam cured PEO and PVP under the descriptions of GKG-1 and GPPG-1 for wound care.
[0008] Adhesive materials can be generally described as being hydophobic or hydrophilic. Examples of hydrophobic adhesives include such familiar items as adhesive tape and bandages. Hydrophobic adhesive materials are most often produced from vinyl based monomers then coated on various flexible polymeric backings which provide for utility as devices to hold other materials such as gauze for maintaining wound dressings in place and in common household uses.
[0009] Pressure sensitive hydrophilic adhesives have been developed that provide for a broad range of applications where such materials come into contact with human skin and tissues. Such adhesive materials can be produced by various methods and formulations that provide physical and mechanical properties specific to intended applications. Examples include formulations that produce films and membranes by cross-linking hydrophilic polymers in combination with various humectants, tackifiers, photoinitiators and cross-linkers that under proper conditions providing for efficiencies for wound care, electro-conductive membranes used for physiological monitoring, drug transfer, fluid absorption, in vivo implantation, sealing and adhesion prevention after surgery.
[0010] Adhesive hydrogels can be produced by several methods common to the practice that include cross-linking adhesive producing hydrogels by chemical methods, photo-polymerization using ultraviolet light or by high energy means employing gamma or e-beam radiation. The following examples are general descriptions of a range of methods and chemical compounds common to production of such adhesive hydrogels that can be made to demonstrate the mechanical and ultrasound properties necessary for the device of this invention.
[0011] Production of adhesive hydrogels for electrical conductivity and wound dressings has been long known in the art. Earlier devices were based on chemical cross-linking using various natural gums and long chain polysaccharides, humectants and takifiers. A formulation containing approximately 55% of a polysaccharide such as karaya when blended with 5 to 10% water, the remainder being hydric alcohols, glycerol being a majority and optionally, the minority propylene glycol, will form adhesive hydrogels when heated in the range of 75 degrees centigrade followed by cooling. Optionally, mechanical properties can be varied by addition of cellulose or other fibrous materials and electrical conductivity enabled by inclusion of alkaline salts in the formulations.
[0012] Another example of such formulation and method involves blending a mixture of about 3 to 4% polyvinyl alcohol, 30 to 35% polyvinylpyrrolidone, a hydric alcohol, such as propylene glycol or glycerol in the amount of 20 to 25%, the remainder being water. When the reactants are heated to 125 to 130 degrees centigrade in a suitable reactor, followed by cooling and subsequent casting on a suitable release sheet, an adhesive hydrogel is formed. A scrim composed of woven or non-woven fibers may be added to improve mechanical properties and maintain structural integrity both during casting and in the final product.
[0013] The adhesive properties may be varied to better conform to end use by additions of materials such as polyacrylic acid, poly-2-acrylamido 2-methyl propane sulfonic acid, gums and various polysaccharides, i.e., carrageenan, locust bean, karaya and alginate derivatives. Addition of commercially available polymers such as carboxymethyl cellulose, hydroxypropylmethyl cellulose and hydroxyethyl cellulose can also be added to the formulation to alter structural properties.
[0014] A further method of producing adhesive hydrogels involves the use thermal or photo-initiating compounds to cross-link solutions of monomers such as acrylic acid, methacrylic acid, or salts thereof, that have been dissolved or dispersed in propylene glycol, glycerol, or other polyhydric alcohols, together with a cross-linking agent which can include, polymercaptans, diethylene glycol diacrylate, trimethylolpropane trithioglycolate, tetraethyleneglycol dimethacrylate, polyethylene glycol, and others, and a thermal or photo polymerization initiator.
[0015] Should the desired cross-linking mechanism be that of thermal initiation or used as an adjunct to photo-initiation, useful compounds for such purpose can include benzoyl peroxide, ammonium persulfate, sodium bisulfite and potassium persulfate. In the case where the preferred polymerization mechanism is photo-initiation by ultraviolet radiation, certain dyes or a UV photo initiator such as 2-hydroxy-1[4-(hydroxyethoxy)phenyl]-2-methyl-1-propane can propagate the polymerization mechanism. From a monomer solution consisting of 30% glycerol, 15% acrylic acid, 1% diethylene glycol diacrylate, to which is added 1% 2-hydroxy-1[4-(hydroxyethoxy)phenyl]-2-methyl-1-propane as a photo-initiator, an adhesive hydrogel can be produced by subsequent exposure to UV light for approximately five minutes in the range of 365 nm at an intensity of 10 mw/cm 2 . By varying the concentration of the cross-linker, the total polymerization time and mechanical properties can be controlled.
[0016] In addition to use of chemical and photo-initiated cross-linking to form adhesive hydrogels, high energy radiation sources, primarily E-beam and to a lesser degree gamma, are also used in industrial settings to produce membranes and pressure sensitive adhesive hydrogels for applications such as electrical conductors for physiological monitoring, wound healing and sealants for medical devices.
[0017] It is well known that solutions of compounds such as PEO, PVP, and PVA can be cross-linked by gamma and e-beam radiation to form coherent non-adhesive gels. Conversely, U.S. Pat. No. 4,699,146 to Sieverding describes formulations and methods to produce water-insoluble, hydrophilic, pressure-sensitive adhesive membranes that exhibit elastomeric and conformal characteristics. These adhesive hydrogels include irradiation cross-linked synthetic organic polymers, such as PVP and PEO, consisting of three-dimensional matrices, and adhesive plasticizers that due to boiling points are essentially non-volatile. The adhesive hydrogels can be used either as coatings on supporting substrates, such as a woven or non-woven scrim, a release liner or as a self-supporting layer. Sieverding also describes various devices made using such adhesives presenting as bandages, wound dressings, cosmetic masks, electrically conductive and ostomy devices, together with methods for preparing and using the adhesive hydrogels. In one embodiment, the adhesive hydrogel is made electro-conductive by addition of a salt such as magnesium acetate; thereby, making it suitable for attachment to the body for monitoring electrical signals emanating from the body. One such example demonstrates a pressure sensitive, electro-conductive adhesive hydrogel composed of polyvinylpyrrolidone cross-linked by ionizing radiation, a polyalkylene glycol plasticizer, water and a salt selected from ammonium acetate, magnesium acetate or magnesium sulfate.
[0018] The cross-linked polymer is produced by irradiation of a solution or dispersion of the gel-forming uncross-linked synthetic organic polymer in a plasticizer that is water-soluble or water-dispersible, and that is capable of dissolving or dispersing the uncross-linked polymer.
[0019] Sieverding teaches that the radiation dosage required to produce such adhesive hydrogels is influenced by factors of concentration of the uncross-linked polymer in the plasticizer, and the molecular weight of the uncross-linked polymer. Relatively lower dosages of irradiation are required by a relatively higher concentration of the uncross-linked polymer or a relatively higher molecular weight uncross-linked polymer; whereas, a relatively higher amount of irradiation is required by a relatively lower concentration of the uncross-linked polymer or a relatively lower molecular weight uncross-linked polymer. The composition of the plasticizer and its proportion to the remaining plasticizer, and the uncross-linked polymer also affect the dosage requirements.
[0020] In Sieverding's model, irradiation dosages range from about 0.5-7.5 megarads can be used for cross-linking the uncross-linked polymer, with dosages of about 3.5-4.5 megarads being average. For example, a composition containing about 18-22 weight percent, K-90 polyvinylpyrrolidone, about 10-70 weight percent polyethylene glycol having a molecular weight of about 300, and water, dosages in this range are suitable.
[0021] Irradiation is used to induce cross-linking of synthetic organic polymers as previously described. The use of high-energy gamma and E-beam irradiation processing techniques enables continuous production of films and coatings facilitates bulk cross-linking and the use of high speed processing techniques, resulting in high volume continuous production of adhesive-coated substances. The uncross-linked solution can be cast directly on a release liner, that may or may not include a woven or non-woven scrim, in a continuous manner, such that the liner continuously moves from the polymer solution casting device through the radiation source, at which point cross-linked adhesive hydrogels are produced.
SUMMARY OF THE INVENTION
[0022] The present invention teaches adhesive hydrogels as acoustic coupling media attachable to the active face (transducer) of ultrasound instruments (such as probes or scanheads) and to the inner face of latex, polyurethane or other polymeric probe covers; thereby, enabling the transfer of acoustic energy between an ultrasound probe and an object of interest when used in conjunction with a gel or liquid ultrasound couplant on the skin surface. The adhesive hydrogel comprises acoustic transmission media and is adhesive on both sides of the film. Such adhesive hydrogels films are so comprised as to render desirable levels of acoustic transmission with acceptable low levels of acoustic artifacts, distortion and attenuation.
[0023] When such adhesive hydrogel films are adhered to hydrophilic membranes such as the probe covers above described, flexible, self-coupling ultrasound couplants are created such that when used for medical ultrasound imaging, by adherence to the probe face, transmits or “couples” the ultrasound acoustic energy between the transducer and the body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] [0024]FIG. 1 illustrates an inventive embodiment comprising a single layer adhesive acoustic coupling hydrogel membrane that is adhesive on all surfaces.
[0025] [0025]FIG. 2 shows the embodiment of FIG. 1 attached to the active face and body of an ultrasound probe with the other adhesive side prepared for insertion into a protective cover or sheath.
[0026] [0026]FIG. 3 illustrates the embodiment of FIG. 1 attached to the active face and body of an ultrasound probe and further being covered by a protective sheath.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Applicant has discovered that adhesive hydrogels previously utilized for electrical conductivity, wound care and cosmetic applications, or fixed site adhesion of medical devices, etc., as discussed above, are suitable for application between an ultrasound transducer and a non-adhesive protective sleeve or probe cover as a self-coupling ultrasound transmitting membrane.
[0028] The present invention provides a solid, self-coupling membrane that is flexible, conformal to the contour and shape of an ultrasound probe and adhesive on both sides of the hydrogel membrane. The membrane being adhesive on both sides is applied between the transducer and a non-adhesive protective sleeve or probe cover. Thus, with the present invention, the need for a couplant gel inside of the protective sleeve or probe cover is eliminated.
[0029] Due to the composition and structure of such membranes, consisting of from 5 to 95% liquid such as water, humectants, compounds for cross linking and preservation, the remainder being polymeric compounds, the membranes are acoustic self-coupling, having acceptable low levels of artifact and distortion. Such membranes possess properties that constitute sufficient tensile and tear strength to withstand mechanical stresses, while in use during imaging exams.
[0030] As previously discussed, the adhesive hydrogel can be adhered to the inside a probe cover or sleeve, into which the ultrasound probe is then inserted and attached to the adhesive hydrogel or alternatively, the adhesive hydrogel is first attached to the face of the probe and inserted into the protective cover or sheath, to form an acoustically conductive bond that eliminates the requirement for coupling gels or liquids inside the protective sleeve or probe cover.
[0031] [0031]FIGS. 1 through 3 illustrate, by way of example, the application of adhesive, acoustic self-coupling films of the present invention.
[0032] [0032]FIG. 1 illustrates a sheet form of the adhesive, conformable, flexible, elastic, uniform, solid acoustic hydrogel sheet according to an embodiment of the present invention. The adhesive membrane 1 is adhesive on both upper and lower sides and may be adhesive throughout the entire thickness. The membrane may contain filaments of hydrophilic woven or non-woven fiber, i.e. a scrim that functions to provide structural stability and top and bottom liners of treated paper or various polymers.
[0033] The preferred adhesive hydrogel films are produced with a uniform thickness of about 0.05 to about 1.0 mm. The solid, conformable, ultrasound acoustic coupling hydrogel sheet 1 is homogenous in composition throughout and on all surfaces, and is uniform in thickness, thus providing equal and uniform acoustic energy coupling capacity throughout. The conformal hydrogel sheets 1 can be applied in sizes and thickness as necessary to cover the active surface 3 and optionally the body of the transducer 4 (FIG. 2) and securely attached to the transducer body by virtue of its adhesivity. The solid conformable ultrasound self coupling hydrogel film 1 used in this form of the embodiment, is uniform in composition within and on all surfaces, and in use, is applied to the medical ultrasound transducer active surface 3 conforming the film over the active area of the transducer 3 by adhesively securing the hydrogel film 3 to the body of the transducer 4 . The homogenous uniform elastic solid ultrasound coupling hydrogel film 1 of this invention provides a desirable level of acoustic coupling with low acceptable levels of artifact and distortion, when applied and integrally conformed to ultrasound transducers of different sizes and shapes.
[0034] [0034]FIG. 2 Illustrates the adhesive membrane 1 of FIG. 1 attached to the active face 3 and portions of the body 4 of an ultrasound transducer. The adhesive hydrogel 1 encloses, surrounds and tightly conforms to the body 4 of the transducer and is integral to the transducers active surface 3 so as to form a uniform, solid couplant that is integral and couples a desirable level of acoustic energy between the transducer and a probe cover or protective sleeve and, ultimately, to a target body. The hydrogel conformal film covers all or a portion of the transducer body 4 , and is adhesively held in such manner so as to maintain uniform, constant and integral contact of the adhesive hydrogel ultrasound coupling film 1 with the transducer's active face 3 during the ultrasound procedure. The portion of the external surface of the solid, conformal hydrogel film 1 that covers the transducers active surface 3 provides the pathway for acoustic energy transmission or coupling between the transducer and the probe cover or protective sleeve or sheath without the need for a couplant gel inside of the protective sleeve or probe cover.
[0035] [0035]FIG. 3 illustrates the application whereby an adhesive membrane 1 is adhesively attached to the active face 3 of the transducer thus performing as an ultrasound couplant. The adhesive hydrogel 1 and portions of the transducer body 4 are covered with a probe cover or protective polymeric sleeve or membrane 6 which may act as a microbial barrier for procedures involving imaging in the surgical field, ultrasound guided puncture and intercavity exams.
[0036] Furthermore, the embodiment of FIG. 3 enables the transfer of acoustic energy between an ultrasound probe and a target body when used in conjunction with a gel or liquid ultrasound couplant on the skin surface but without the need for a couplant gel inside of the protective sleeve or probe cover.
[0037] The adhesive hydrogels may be manufactured by any appropriate process such as those previously discussed in the “Background” portion. The hydrogels of the present invention are not limited to the aforementioned products or compositions but may include such hydrogel compounds, films and membranes that exhibit properties of adhesivity and ultrasound transmission characteristics.
[0038] While the invention has been described with reference to preferred embodiments it is to be understood that the invention is not limited to the particulars thereof. The present invention is intended to include modifications which would be apparent to those skilled in the art to which the subject matter pertains without deviating from the spirit and scope of the appended claims. | Adhesive hydrogel films as ultrasound couplants wherein such hydrogels are adhesive on both sides for adhering to an ultrasound probe and to a protective sleeve or probe cover which facilitates acoustic coupling between an object such as between the human body and the active area of an ultrasound probe, thereby eliminating the requirement for coupling gels and fluids within the sleeve or cover. | Briefly describe the main idea outlined in the provided context. | [
"FIELD OF THE INVENTION [0001] The present invention is directed to the medical use of ultrasound acoustic energy for imaging, doppler based flow measurement, and therapy.",
"In particular, the present invention pertains to the use of adhesive, acoustic self-coupling hydrogels to couple sound between ultrasound transducers and protective sheaths or covers.",
"BACKGROUND OF THE INVENTION [0002] Ultrasound, as used for medical applications, utilizes high frequencies, typically between 1 and 30 MHz for imaging and flow measurements and between 0.050 and 1.00 MHz for therapy, all of which are poorly transmitted by air and require a medium similar in acoustic properties to tissue, commonly a thick fluid, gel or solid membrane, which displaces air and fills contours between the “eye”",
"or transducer of an ultrasound instrument (such as a probe or scanhead), which converts energy between electrical and acoustic, and the body or object into which the sound is being directed.",
"This medium, by nature of its physical and acoustic properties, serves as an ultrasound acoustic transmission “coupler”",
"between the object of interest and the electronic transducer, thereby acoustically joining the two, so that the sound based information developed can freely pass back and forth between the body and the electronics.",
"Because of the “coupling”",
"effect, this media is commonly referred to as an ultrasound couplant, ultrasound transmission media or acoustic transmission media.",
"[0003] Hydrophilic membranes as coupling media is disclosed, for example, in U.S. Pat. No. 6,039,694 to Larson, et al.",
", which teaches the use of hydrogel films composed of block co-polymers of polyurethane and polyacrylonitrile.",
"The patent discloses application of these materials for ultrasound scanning in the form of shape-conforming films produced by dipping methods, flat membranes that can be stretched over the active surface of an ultrasound probe, scanning through a membrane that is placed in direct contact with skin, and imaging through a latex or other polymeric protective probe cover with such a membrane covering the active area of the transducer and portions of the transducer body.",
"These self-coupling hydrogel films eliminate the requirement for gels and other liquid couplants, and can provide a microbial barrier between the patient and ultrasound probe.",
"[0004] However, by virtue of the composition and mechanical properties, use of films such as those of U.S. Pat. No. 6,039,694 is limited.",
"The films are slippery and lack adhesive characteristics.",
"Such characteristics, while desirable as a scanning surface, tend to allow the membrane to slip off non-horizontal surfaces and slide with the ultrasound probe as it is moved over the surface of the membrane.",
"While the films of U.S. Pat. No. 6,039,694 have sufficient mechanical strength to permit conformal fit by stretching the film over the active face of an ultrasound probe, the absence of adhesive characteristics requires that the membrane be secured to the probe by some mechanical means such as a rubber band or strap.",
"U.S. Pat. No. 5,522,878 to Montecalvo et al.",
"describes a solid, multipurpose, flexible, ultrasonic, biomedical couplant hydrogel in sheet form to facilitate transfer of ultrasound energy to and from a patient.",
"Also described is a method of attaching the sheet to skin to hold the couplant gel in place during an exam, which constitutes a band of pressure sensitive adhesive bonded to plastic foam, such as foamed rubber, that is located along the outer perimeter of the sheet.",
"The hydrogel sheet so described is not adhesive in and of itself, but depends on an unreliable potential that sufficient perspiration will be present to make the gel somewhat tacky in instances where the chemical composition is such that addition of moisture to the hydrogel will result in some degree of tack.",
"The adhesive border, so described, is not acoustic self-coupling, therefore restricting ultrasound scanning to areas exclusive of those covered with adhesive covered foam.",
"[0005] U.S. Pat. No. 5,782,767 to Pretlow, III, describes a pad assembly for coupling ultrasound from a transducer probe into the human body, wherein a humectant, such as glycerin in combination with water, creates sufficient surface tension for a pad containing a mixture of water and a humectant, such as glycerin, to remain attached to the probe face by the weak forces of surface tension when the pad is extracted from the storage container and placed on skin.",
"Since general scanning procedures normally require large volumes of couplant materials, and the transducer is moved over large areas, such as is done in fetal scanning, the device of U.S. Pat. No. 5,782,767 is limited to single site applications, such as is disclosed by Pretlow for monitoring bladder fullness, rather than as a device for general ultrasound scanning procedures, where its design for such use would not be practical.",
"Use of this device for general scanning would rapidly deplete the glycerin and water mixture, and since the acoustic coupling and the weak forces of surface tension rely upon the presence of this mixture of liquids rather than an engineered adhesive, such general use would to a high degree lead to probable loss of acoustic coupling and separation of the couplant pad from the transducer face.",
"[0006] U.S. Pat. No. 5,394,877 to Orr et al.",
"describes a contact medium structure attachable to externally applied medical diagnostic devices for providing self-adherence of a medical device to the skin of a patient thereby eliminating the need for retaining belts or similar means.",
"A contact medium is described that is inherently adhesive, hydrophilic, skin compatible, ultrasonic compatible and pressure sensitive to facilitate self-adhesion of the medical device to the patient's skin.",
"The device of Orr et al.",
"discloses use as an ultrasound conductive medium, however such device provides only for the attachment of one side the adhesive membrane to the skin of a patient and the opposite adhesive side to a medical device such as a transducer for monitoring purposes, and as such, is limited to use on one site once properly placed.",
"The design of the device of Orr et al.",
"restricts use of medical devices to one area of the body and prevents free gliding motions of a medical device, such as an ultrasound transducer, over the body of a patient, as is necessary for medical imaging procedures.",
"For example, ultrasound imaging over large external areas or imaging from within the body of a patient is inconsistent with its stated use or structural design.",
"[0007] The formulation, manufacture and use of adhesive hydrogels for products that form an interface with skin and tissue Is known to the artisan as is the formulation, preparation and use of adhesive hydrophilic compounds for wound treatment and electrically conductive devices.",
"Adhesive hydrogels are commercially available from producers including 3M Corporation, Ludlow Technical Products and Lectec Corporation.",
"For example, Ludlow Technical Products produces UV cured electrically conductive gels designated Series RG 63B, and E-Beam cured PEO and PVP under the descriptions of GKG-1 and GPPG-1 for wound care.",
"[0008] Adhesive materials can be generally described as being hydophobic or hydrophilic.",
"Examples of hydrophobic adhesives include such familiar items as adhesive tape and bandages.",
"Hydrophobic adhesive materials are most often produced from vinyl based monomers then coated on various flexible polymeric backings which provide for utility as devices to hold other materials such as gauze for maintaining wound dressings in place and in common household uses.",
"[0009] Pressure sensitive hydrophilic adhesives have been developed that provide for a broad range of applications where such materials come into contact with human skin and tissues.",
"Such adhesive materials can be produced by various methods and formulations that provide physical and mechanical properties specific to intended applications.",
"Examples include formulations that produce films and membranes by cross-linking hydrophilic polymers in combination with various humectants, tackifiers, photoinitiators and cross-linkers that under proper conditions providing for efficiencies for wound care, electro-conductive membranes used for physiological monitoring, drug transfer, fluid absorption, in vivo implantation, sealing and adhesion prevention after surgery.",
"[0010] Adhesive hydrogels can be produced by several methods common to the practice that include cross-linking adhesive producing hydrogels by chemical methods, photo-polymerization using ultraviolet light or by high energy means employing gamma or e-beam radiation.",
"The following examples are general descriptions of a range of methods and chemical compounds common to production of such adhesive hydrogels that can be made to demonstrate the mechanical and ultrasound properties necessary for the device of this invention.",
"[0011] Production of adhesive hydrogels for electrical conductivity and wound dressings has been long known in the art.",
"Earlier devices were based on chemical cross-linking using various natural gums and long chain polysaccharides, humectants and takifiers.",
"A formulation containing approximately 55% of a polysaccharide such as karaya when blended with 5 to 10% water, the remainder being hydric alcohols, glycerol being a majority and optionally, the minority propylene glycol, will form adhesive hydrogels when heated in the range of 75 degrees centigrade followed by cooling.",
"Optionally, mechanical properties can be varied by addition of cellulose or other fibrous materials and electrical conductivity enabled by inclusion of alkaline salts in the formulations.",
"[0012] Another example of such formulation and method involves blending a mixture of about 3 to 4% polyvinyl alcohol, 30 to 35% polyvinylpyrrolidone, a hydric alcohol, such as propylene glycol or glycerol in the amount of 20 to 25%, the remainder being water.",
"When the reactants are heated to 125 to 130 degrees centigrade in a suitable reactor, followed by cooling and subsequent casting on a suitable release sheet, an adhesive hydrogel is formed.",
"A scrim composed of woven or non-woven fibers may be added to improve mechanical properties and maintain structural integrity both during casting and in the final product.",
"[0013] The adhesive properties may be varied to better conform to end use by additions of materials such as polyacrylic acid, poly-2-acrylamido 2-methyl propane sulfonic acid, gums and various polysaccharides, i.e., carrageenan, locust bean, karaya and alginate derivatives.",
"Addition of commercially available polymers such as carboxymethyl cellulose, hydroxypropylmethyl cellulose and hydroxyethyl cellulose can also be added to the formulation to alter structural properties.",
"[0014] A further method of producing adhesive hydrogels involves the use thermal or photo-initiating compounds to cross-link solutions of monomers such as acrylic acid, methacrylic acid, or salts thereof, that have been dissolved or dispersed in propylene glycol, glycerol, or other polyhydric alcohols, together with a cross-linking agent which can include, polymercaptans, diethylene glycol diacrylate, trimethylolpropane trithioglycolate, tetraethyleneglycol dimethacrylate, polyethylene glycol, and others, and a thermal or photo polymerization initiator.",
"[0015] Should the desired cross-linking mechanism be that of thermal initiation or used as an adjunct to photo-initiation, useful compounds for such purpose can include benzoyl peroxide, ammonium persulfate, sodium bisulfite and potassium persulfate.",
"In the case where the preferred polymerization mechanism is photo-initiation by ultraviolet radiation, certain dyes or a UV photo initiator such as 2-hydroxy-1[4-(hydroxyethoxy)phenyl]-2-methyl-1-propane can propagate the polymerization mechanism.",
"From a monomer solution consisting of 30% glycerol, 15% acrylic acid, 1% diethylene glycol diacrylate, to which is added 1% 2-hydroxy-1[4-(hydroxyethoxy)phenyl]-2-methyl-1-propane as a photo-initiator, an adhesive hydrogel can be produced by subsequent exposure to UV light for approximately five minutes in the range of 365 nm at an intensity of 10 mw/cm 2 .",
"By varying the concentration of the cross-linker, the total polymerization time and mechanical properties can be controlled.",
"[0016] In addition to use of chemical and photo-initiated cross-linking to form adhesive hydrogels, high energy radiation sources, primarily E-beam and to a lesser degree gamma, are also used in industrial settings to produce membranes and pressure sensitive adhesive hydrogels for applications such as electrical conductors for physiological monitoring, wound healing and sealants for medical devices.",
"[0017] It is well known that solutions of compounds such as PEO, PVP, and PVA can be cross-linked by gamma and e-beam radiation to form coherent non-adhesive gels.",
"Conversely, U.S. Pat. No. 4,699,146 to Sieverding describes formulations and methods to produce water-insoluble, hydrophilic, pressure-sensitive adhesive membranes that exhibit elastomeric and conformal characteristics.",
"These adhesive hydrogels include irradiation cross-linked synthetic organic polymers, such as PVP and PEO, consisting of three-dimensional matrices, and adhesive plasticizers that due to boiling points are essentially non-volatile.",
"The adhesive hydrogels can be used either as coatings on supporting substrates, such as a woven or non-woven scrim, a release liner or as a self-supporting layer.",
"Sieverding also describes various devices made using such adhesives presenting as bandages, wound dressings, cosmetic masks, electrically conductive and ostomy devices, together with methods for preparing and using the adhesive hydrogels.",
"In one embodiment, the adhesive hydrogel is made electro-conductive by addition of a salt such as magnesium acetate;",
"thereby, making it suitable for attachment to the body for monitoring electrical signals emanating from the body.",
"One such example demonstrates a pressure sensitive, electro-conductive adhesive hydrogel composed of polyvinylpyrrolidone cross-linked by ionizing radiation, a polyalkylene glycol plasticizer, water and a salt selected from ammonium acetate, magnesium acetate or magnesium sulfate.",
"[0018] The cross-linked polymer is produced by irradiation of a solution or dispersion of the gel-forming uncross-linked synthetic organic polymer in a plasticizer that is water-soluble or water-dispersible, and that is capable of dissolving or dispersing the uncross-linked polymer.",
"[0019] Sieverding teaches that the radiation dosage required to produce such adhesive hydrogels is influenced by factors of concentration of the uncross-linked polymer in the plasticizer, and the molecular weight of the uncross-linked polymer.",
"Relatively lower dosages of irradiation are required by a relatively higher concentration of the uncross-linked polymer or a relatively higher molecular weight uncross-linked polymer;",
"whereas, a relatively higher amount of irradiation is required by a relatively lower concentration of the uncross-linked polymer or a relatively lower molecular weight uncross-linked polymer.",
"The composition of the plasticizer and its proportion to the remaining plasticizer, and the uncross-linked polymer also affect the dosage requirements.",
"[0020] In Sieverding's model, irradiation dosages range from about 0.5-7.5 megarads can be used for cross-linking the uncross-linked polymer, with dosages of about 3.5-4.5 megarads being average.",
"For example, a composition containing about 18-22 weight percent, K-90 polyvinylpyrrolidone, about 10-70 weight percent polyethylene glycol having a molecular weight of about 300, and water, dosages in this range are suitable.",
"[0021] Irradiation is used to induce cross-linking of synthetic organic polymers as previously described.",
"The use of high-energy gamma and E-beam irradiation processing techniques enables continuous production of films and coatings facilitates bulk cross-linking and the use of high speed processing techniques, resulting in high volume continuous production of adhesive-coated substances.",
"The uncross-linked solution can be cast directly on a release liner, that may or may not include a woven or non-woven scrim, in a continuous manner, such that the liner continuously moves from the polymer solution casting device through the radiation source, at which point cross-linked adhesive hydrogels are produced.",
"SUMMARY OF THE INVENTION [0022] The present invention teaches adhesive hydrogels as acoustic coupling media attachable to the active face (transducer) of ultrasound instruments (such as probes or scanheads) and to the inner face of latex, polyurethane or other polymeric probe covers;",
"thereby, enabling the transfer of acoustic energy between an ultrasound probe and an object of interest when used in conjunction with a gel or liquid ultrasound couplant on the skin surface.",
"The adhesive hydrogel comprises acoustic transmission media and is adhesive on both sides of the film.",
"Such adhesive hydrogels films are so comprised as to render desirable levels of acoustic transmission with acceptable low levels of acoustic artifacts, distortion and attenuation.",
"[0023] When such adhesive hydrogel films are adhered to hydrophilic membranes such as the probe covers above described, flexible, self-coupling ultrasound couplants are created such that when used for medical ultrasound imaging, by adherence to the probe face, transmits or “couples”",
"the ultrasound acoustic energy between the transducer and the body.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0024] [0024 ]FIG. 1 illustrates an inventive embodiment comprising a single layer adhesive acoustic coupling hydrogel membrane that is adhesive on all surfaces.",
"[0025] [0025 ]FIG. 2 shows the embodiment of FIG. 1 attached to the active face and body of an ultrasound probe with the other adhesive side prepared for insertion into a protective cover or sheath.",
"[0026] [0026 ]FIG. 3 illustrates the embodiment of FIG. 1 attached to the active face and body of an ultrasound probe and further being covered by a protective sheath.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0027] Applicant has discovered that adhesive hydrogels previously utilized for electrical conductivity, wound care and cosmetic applications, or fixed site adhesion of medical devices, etc.",
", as discussed above, are suitable for application between an ultrasound transducer and a non-adhesive protective sleeve or probe cover as a self-coupling ultrasound transmitting membrane.",
"[0028] The present invention provides a solid, self-coupling membrane that is flexible, conformal to the contour and shape of an ultrasound probe and adhesive on both sides of the hydrogel membrane.",
"The membrane being adhesive on both sides is applied between the transducer and a non-adhesive protective sleeve or probe cover.",
"Thus, with the present invention, the need for a couplant gel inside of the protective sleeve or probe cover is eliminated.",
"[0029] Due to the composition and structure of such membranes, consisting of from 5 to 95% liquid such as water, humectants, compounds for cross linking and preservation, the remainder being polymeric compounds, the membranes are acoustic self-coupling, having acceptable low levels of artifact and distortion.",
"Such membranes possess properties that constitute sufficient tensile and tear strength to withstand mechanical stresses, while in use during imaging exams.",
"[0030] As previously discussed, the adhesive hydrogel can be adhered to the inside a probe cover or sleeve, into which the ultrasound probe is then inserted and attached to the adhesive hydrogel or alternatively, the adhesive hydrogel is first attached to the face of the probe and inserted into the protective cover or sheath, to form an acoustically conductive bond that eliminates the requirement for coupling gels or liquids inside the protective sleeve or probe cover.",
"[0031] [0031 ]FIGS. 1 through 3 illustrate, by way of example, the application of adhesive, acoustic self-coupling films of the present invention.",
"[0032] [0032 ]FIG. 1 illustrates a sheet form of the adhesive, conformable, flexible, elastic, uniform, solid acoustic hydrogel sheet according to an embodiment of the present invention.",
"The adhesive membrane 1 is adhesive on both upper and lower sides and may be adhesive throughout the entire thickness.",
"The membrane may contain filaments of hydrophilic woven or non-woven fiber, i.e. a scrim that functions to provide structural stability and top and bottom liners of treated paper or various polymers.",
"[0033] The preferred adhesive hydrogel films are produced with a uniform thickness of about 0.05 to about 1.0 mm.",
"The solid, conformable, ultrasound acoustic coupling hydrogel sheet 1 is homogenous in composition throughout and on all surfaces, and is uniform in thickness, thus providing equal and uniform acoustic energy coupling capacity throughout.",
"The conformal hydrogel sheets 1 can be applied in sizes and thickness as necessary to cover the active surface 3 and optionally the body of the transducer 4 (FIG.",
"2) and securely attached to the transducer body by virtue of its adhesivity.",
"The solid conformable ultrasound self coupling hydrogel film 1 used in this form of the embodiment, is uniform in composition within and on all surfaces, and in use, is applied to the medical ultrasound transducer active surface 3 conforming the film over the active area of the transducer 3 by adhesively securing the hydrogel film 3 to the body of the transducer 4 .",
"The homogenous uniform elastic solid ultrasound coupling hydrogel film 1 of this invention provides a desirable level of acoustic coupling with low acceptable levels of artifact and distortion, when applied and integrally conformed to ultrasound transducers of different sizes and shapes.",
"[0034] [0034 ]FIG. 2 Illustrates the adhesive membrane 1 of FIG. 1 attached to the active face 3 and portions of the body 4 of an ultrasound transducer.",
"The adhesive hydrogel 1 encloses, surrounds and tightly conforms to the body 4 of the transducer and is integral to the transducers active surface 3 so as to form a uniform, solid couplant that is integral and couples a desirable level of acoustic energy between the transducer and a probe cover or protective sleeve and, ultimately, to a target body.",
"The hydrogel conformal film covers all or a portion of the transducer body 4 , and is adhesively held in such manner so as to maintain uniform, constant and integral contact of the adhesive hydrogel ultrasound coupling film 1 with the transducer's active face 3 during the ultrasound procedure.",
"The portion of the external surface of the solid, conformal hydrogel film 1 that covers the transducers active surface 3 provides the pathway for acoustic energy transmission or coupling between the transducer and the probe cover or protective sleeve or sheath without the need for a couplant gel inside of the protective sleeve or probe cover.",
"[0035] [0035 ]FIG. 3 illustrates the application whereby an adhesive membrane 1 is adhesively attached to the active face 3 of the transducer thus performing as an ultrasound couplant.",
"The adhesive hydrogel 1 and portions of the transducer body 4 are covered with a probe cover or protective polymeric sleeve or membrane 6 which may act as a microbial barrier for procedures involving imaging in the surgical field, ultrasound guided puncture and intercavity exams.",
"[0036] Furthermore, the embodiment of FIG. 3 enables the transfer of acoustic energy between an ultrasound probe and a target body when used in conjunction with a gel or liquid ultrasound couplant on the skin surface but without the need for a couplant gel inside of the protective sleeve or probe cover.",
"[0037] The adhesive hydrogels may be manufactured by any appropriate process such as those previously discussed in the “Background”",
"portion.",
"The hydrogels of the present invention are not limited to the aforementioned products or compositions but may include such hydrogel compounds, films and membranes that exhibit properties of adhesivity and ultrasound transmission characteristics.",
"[0038] While the invention has been described with reference to preferred embodiments it is to be understood that the invention is not limited to the particulars thereof.",
"The present invention is intended to include modifications which would be apparent to those skilled in the art to which the subject matter pertains without deviating from the spirit and scope of the appended claims."
] |
TECHNICAL FIELD OF THE INVENTION
The present invention is related to the field of automatic focusing of a light beam onto the surface of a recording medium and, more particularly, to a system and associated method for quickly acquiring focus on the surface of a rotating optical recording disk.
BACKGROUND OF THE INVENTION
Storage systems that use optical disks as the storage media lose time when access to the recorded data waits upon the optical focusing servomechanism to acquire focus onto the recording surface of the spinning optical disk.
A patent of interest for its teachings relevant to the state of the art is U.S. Pat. No. 4,497,047 entitled "Optical Disk Player with Focus Control During Search Mode" by K. Fujiie et al. The focusing control system of the patent responds to the need of quickly acquiring focus when shifting transversely across a plurality of tracks to a new read position. The system reduces the gain of the focusing servo but maintains servo control at a defocused level such that the servo control system does not have to commence the acquisition of focus at the new read position from a start or reference position. Additionally, if a sharp focus was to be maintained as the objective lens moved in the traverse manner across the recording tracks it would be subjected to vibratory movements as the servo mechanism attempted to lock onto the different refelective patterns that passed through the field of view of the lens as it was moved to the new read position.
Another patent of interest is U.S. Pat. No. 4,512,003 entitled "Control Circuitry for Preliminary Focusing of Light on a Record Medium Surface in an Optical Reproducing Apparatus" by S. Kimura et al. The apparatus of the patent uses a preliminary focusing signal which is derived from a signal generator such that a first polarity signal, that varies rapidly at one polarity and then varies slowly towards a second predetermined level of opposite polarity, creates a zero crossover point corresponding to a preliminary focus point for the servo system. Once preliminary focusing is achieved, the system shifts into the second level of focus utilizing a focus error signal generated by the focusing servo.
A third patent of interest is U.S. Pat. No. 4,677,605 entitled "Focus Acquisition and Maintenance for Optical Disk System" by M. Abed. In the system of that patent there is also disclosed a two-level focusing technique which utilizes the asymmetrical properties of a light beam reflected from the surface of the recording disk onto a quad detector wherein the electrical signals resulting therefrom are compared against a threshold value as the objective lens is driven towards a focusing position and when the electrical signals'value compares to a known threshold value, indicating a coarse focus, the system is switched to a fine focus servo configuration so that the fine focus can be achieved. Additionally, in column 8, lines 41-49, it is mentioned that the method of the invention is used to avoid a false focus on the overcoat layer of the optical disk. This is accomplished by having the objective lens relatively close to the disk or focused behind the disk and as the objective lens is ramped away from the disk the first legitimate focus appears on the recording material and not on the overcoat layer. In this manner a false focus is averted.
A fourth patent of interest is U.S. Pat. No. 4,396,959 entitiled "Data Transducer Position Control System for Rotating Disk Data Storage Equipment" by J. N. Harrison et al. The system of that patent uses wide-driving pulses to quickly move an optical head across many tracks when the track to be focused on is located a considerable distance from the optical head's initial position.
SUMMARY OF THE PREFERRED EMBODIMENTS
In the method embodiment of the present invention a focus acquisition servo system of the type that is used to focus a read beam onto the recording surface of an optical disk, of the type that has an overcoat layer, is achieved by commencing focus on the optical disk as it is spinning up to speed and by initiating an optimal two-step jump of the actuator to place it close to the desired focus position. The actuator is first accelerated (jumped) at maximum acceleration in the direction which is desired and then decelerated at maximum allowable deceleration to a rest position. The focus gain is monitored during movement to see if the disk surface (focus) has passed under the lens. If not, then the actuator is jumped again until the disk surface (focus) does pass under the lens. At this point the lens can be jumped back and ramped to the desired focus position. While speed is being achieved, the read function of the system is activated and the lens system is then ramped to the desired focus position.
Additionally, with a preformatted disk an address can be read to verify that the actuator is focused on the disk and not on the cover sheet.
Attempting to focus on a disk as it is spinning up to speed is further complicated by the fact that the edges of the disk tend to wobble causing the recording surface to move up and down with a wave action. The present invention overcomes this complication.
From the foregoing it can be seen that it is a primary object of the present invention to provide an improved optical focus acquisition system and method.
It is another object of the present invention to provide a system for focusing quickly onto the surface of an optical disk by commencing the focus operation as the disk is coming up to speed which facilitates final focusing when the disk is at speed.
These and other objects of the present invention will become more apparent when taken in conjunction with the following drawings wherein like characters indicate like parts and which drawings form a part of the present description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the preferred apparatus embodiment of the invention.
FIGS. 2A-2D are a group of waveforms illustrating the signals appearing at selected locations in the apparatus depicted in FIG. 1.
FIGS. 3A and 3B, connected at the point labeled ○A , illustrate in flow chart form the operating sequence of the preferred method of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 there is illustrated an optical focusing system for an optical recording disk 15. The system utilizes a coherent light source, such as a laser 10, for directing a light beam through a prism set 11 and onto a mirror 12 which in turn directs the light beam through a focus actuator 13, containing an object lens 14, and onto the recording surface 15B of an optical recording disk 15. The optical recording disk 15 generally, has an overcoat layer 15A which is used to protect the recording surface 15B. Reflected light, from the optical recording disk, passes back through the object lens 14 to the mirror 12 and to the reflective surface 21, within the prism 11, which directs the reflected light to a lens 20 and onto a quad photodetector 16. The photodetector 16 converts the light beam impinging thereon into two analog electrical signals, FOCUS ERROR and FOCUS GAIN by interconnecting each of the four photodetectors in a well-known manner. The analog signals are coupled to a digital servo controller 17 through A/D converters 24 and 22, respectively. The FOCUS ERROR signal is also an input to an analog servo 18. The output signal from the analog servo 18 is applied to a first switch terminal of a SPST switch 19. The switch 19 is activated by a signal from the servo controlled 17. A two-input summer 28 has one +input connected to a second switch terminal of the switch 19 and the other +input connected to receive an output from the servo controller 17 via a D/A converter 26. The signal from the summer 28 drives the focus actuator 13 towards or away from the disk 15.
Referring to FIG. 2C, from a start position the actuator 13 is pulsed with a voltage pulse 30 of magnitude and width to cause the actuator to move with a maximum acceleration (jump) towards a first position. The pulses are generated by the servo controller 17. Immediately thereafter a deceleration pulse 32 is applied to the actuator to cause the actuator to rest at the first position evidenced by the horizontal line 34. At this point, focus has not been passed (determined by observing FOCUS GAIN FIG. 2A). A second pulse 36 is applied, followed by a deceleration pulse 38 which causes the actuator to move quickly to a second rest position evidenced by the horizontal line 40. As the actuator moved between the first position and the second position the desired focus positioned was passed as evidenced by the peak 50 in the FOCUS GAIN signal. At this point, the actuator is impulsed with a pulse 42 driving the acutuator back towards the first position and with a deceleration pulse 44 to reach the position evidenced by the horizontal line 46. At this position, the actuator passed the focus point again, as evidenced by the peak 52 in the FOCUS GAIN signal. Thereafter, the servo controller 17 outputs a FOCUS RAMP signal to drive the focus actuator to the desired focus position. As this is done, the FOCUS GAIN is shown increasing towards and past a first threshold level T 1 in response to a FOCUS RAMP signal, illustrated in FIG. 2C, driving in a downward ramp direction which corresponds to the focus actuator (object lens 14) being driven away from the recording surface 15B of the optical disk 15 and simultaneously, the FOCUS ERROR signal, illustrated in FIG. 2B, is shown increasing towards a negative peak value. With the FOCUS GAIN passing the threshold, the FOCUS ERROR signal begins to reach its peak negative value indicating that the objective lens is being driven towards a correct focus position. With the FOCUS ERROR signal changing from a negative value to a positive value and the FOCUS GAIN being at a maximum value the ramping operation is terminated and the focus servo is switched ON, as referenced by the step in the waveform of FIG. 2D, by a switching signal from the servo controller 17, which closes the switch 19.
Referring now to FIGS. 3A and 3B, which illustrate the operation method of the preferred apparatus embodiment in flow diagram form, the system is initialized in operation via the initialized variables block 200 which then moves the operating sequence to the question block 201 which requests whether focus is to be acquired while spinning up the disk. If the answer is NO, the system goes to block 204 to achieve focus in the classical manner by following the flow along the line labeled ○A . If the answer is YES, focus is initiated for the quick mode and the question block 202 is activated, sampling the motion of the disk to answer YES when the disk is in motion. If the answer is NO, the question block 202 branches to block 203 which waits for the disk to start moving before outputting an inquiry to block 202. When the disk is in motion, question block 202 will output a YES answer which will turn on the read laser per the action block 205. If the read laser is not turned on as an answer to the questioning block 206, a NO branch will occur to a block 208 which will provide a false signal along the line terminating with an ○A . That line will be picked up at the input to a question block 209. The question asked will be is it OK to focus with the read laser off. If the answer is NO, a branch will be taken to a report status block 215 indicating a fault status and the program will exit at block 216. If the answer to the questioning block 209 is YES, focusing will be activated by stepping the objective lens (activator) to a start position as evidenced by action block 210. With the objective lens at the start position it is jumped to a first position by action block 220 and the gain is monitored to determine if the lens moved past the focus position. This question is asked in block 222. If the answer is NO the lens is jumped again. This process continues until the answer is YES. The lens is then jumped back, by action block 224. The magnitude of the jump varies for different systems and is ideally adjusted to provide the required crossing of focus within two jumps. Next, the lens will be ramped away from the disk until the focus again is at some value below a threshold. In the preferred embodiment, the threshold value was a gain of 80. This is reflected in the action block 211. Once achieved, the system moves to the question block 212 which questions whether the gain is below the threshold value and additionally whether the FOCUS ERROR signal is below a predetermined threshold. If the answer is YES, the system branches to block 213 which sets the FOCUS GAIN at some nominal value and locks the focus servo into its fine focusing mode. Once accomplished, a question block 214 questions whether focus has been achieved. If the answer is NO, the system branches to a question and action box 217 which permits three retries for focus before moving to a report status mode 215 (reporting a default). If the system is in focus the report status mode 215 is entered indicating the achievement of the fine focus.
Moving back to the questioning block 212, if the FOCUS ERROR signal is greater than a threshold value, in the preferred embodiment the threshold is 128, a NO response is achieved from the question block 212 and the program branches back to the input to the question block 211 until the FOCUS ERROR signal reaches a value which is below 128. In a like manner, if the FOCUS GAIN is greater than 80, the program branches back to the input to action block 211 and ramps the lens further away from the disk until the FOCUS GAIN is less than 80.
The flow diagram steps shown in FIGS. 3A and 3B can be implemented with a software program for driving the servo controller 17.
In conclusion, there has been described a system (apparatus) and a method for quickly acquiring focus onto the recording surface of an optical disk by focusing the optical system onto the recording medium as the disk starts spinning and by jumping the actuator to a position close to the final focus position while the disk is reaching operational speed and by switching in the servo to quickly focus onto the recording surface rather than the protective surface.
While there has been shown what are considered to be the preferred embodiments of the invention, it will be manifest that many modifications may be made therein without departing from the essential spirit of the invention. It is intended, therefore, in the annexed claims to cover all such changes and modifications as may fall within the true scope of the invention. | A focus acquisition servo system and method which speeds the acquisition process by focusing on the recording media of an optical disk while the disk is coming up to speed. Focus is accomplished by jumping the focus actuator from a start position close to the focus position and by ramping the focus actuator away from the surface of the disk while monitoring focus gain. When the focus gain reaches a peak amplitude the disk is in rough focus, ramping is stopped and the focus servo system is activated to lock the focus actuator onto a fine focus on the disk's recording media. | Briefly outline the background technology and the problem the invention aims to solve. | [
"TECHNICAL FIELD OF THE INVENTION The present invention is related to the field of automatic focusing of a light beam onto the surface of a recording medium and, more particularly, to a system and associated method for quickly acquiring focus on the surface of a rotating optical recording disk.",
"BACKGROUND OF THE INVENTION Storage systems that use optical disks as the storage media lose time when access to the recorded data waits upon the optical focusing servomechanism to acquire focus onto the recording surface of the spinning optical disk.",
"A patent of interest for its teachings relevant to the state of the art is U.S. Pat. No. 4,497,047 entitled "Optical Disk Player with Focus Control During Search Mode"",
"by K. Fujiie et al.",
"The focusing control system of the patent responds to the need of quickly acquiring focus when shifting transversely across a plurality of tracks to a new read position.",
"The system reduces the gain of the focusing servo but maintains servo control at a defocused level such that the servo control system does not have to commence the acquisition of focus at the new read position from a start or reference position.",
"Additionally, if a sharp focus was to be maintained as the objective lens moved in the traverse manner across the recording tracks it would be subjected to vibratory movements as the servo mechanism attempted to lock onto the different refelective patterns that passed through the field of view of the lens as it was moved to the new read position.",
"Another patent of interest is U.S. Pat. No. 4,512,003 entitled "Control Circuitry for Preliminary Focusing of Light on a Record Medium Surface in an Optical Reproducing Apparatus"",
"by S. Kimura et al.",
"The apparatus of the patent uses a preliminary focusing signal which is derived from a signal generator such that a first polarity signal, that varies rapidly at one polarity and then varies slowly towards a second predetermined level of opposite polarity, creates a zero crossover point corresponding to a preliminary focus point for the servo system.",
"Once preliminary focusing is achieved, the system shifts into the second level of focus utilizing a focus error signal generated by the focusing servo.",
"A third patent of interest is U.S. Pat. No. 4,677,605 entitled "Focus Acquisition and Maintenance for Optical Disk System"",
"by M. Abed.",
"In the system of that patent there is also disclosed a two-level focusing technique which utilizes the asymmetrical properties of a light beam reflected from the surface of the recording disk onto a quad detector wherein the electrical signals resulting therefrom are compared against a threshold value as the objective lens is driven towards a focusing position and when the electrical signals'value compares to a known threshold value, indicating a coarse focus, the system is switched to a fine focus servo configuration so that the fine focus can be achieved.",
"Additionally, in column 8, lines 41-49, it is mentioned that the method of the invention is used to avoid a false focus on the overcoat layer of the optical disk.",
"This is accomplished by having the objective lens relatively close to the disk or focused behind the disk and as the objective lens is ramped away from the disk the first legitimate focus appears on the recording material and not on the overcoat layer.",
"In this manner a false focus is averted.",
"A fourth patent of interest is U.S. Pat. No. 4,396,959 entitiled "Data Transducer Position Control System for Rotating Disk Data Storage Equipment"",
"by J. N. Harrison et al.",
"The system of that patent uses wide-driving pulses to quickly move an optical head across many tracks when the track to be focused on is located a considerable distance from the optical head's initial position.",
"SUMMARY OF THE PREFERRED EMBODIMENTS In the method embodiment of the present invention a focus acquisition servo system of the type that is used to focus a read beam onto the recording surface of an optical disk, of the type that has an overcoat layer, is achieved by commencing focus on the optical disk as it is spinning up to speed and by initiating an optimal two-step jump of the actuator to place it close to the desired focus position.",
"The actuator is first accelerated (jumped) at maximum acceleration in the direction which is desired and then decelerated at maximum allowable deceleration to a rest position.",
"The focus gain is monitored during movement to see if the disk surface (focus) has passed under the lens.",
"If not, then the actuator is jumped again until the disk surface (focus) does pass under the lens.",
"At this point the lens can be jumped back and ramped to the desired focus position.",
"While speed is being achieved, the read function of the system is activated and the lens system is then ramped to the desired focus position.",
"Additionally, with a preformatted disk an address can be read to verify that the actuator is focused on the disk and not on the cover sheet.",
"Attempting to focus on a disk as it is spinning up to speed is further complicated by the fact that the edges of the disk tend to wobble causing the recording surface to move up and down with a wave action.",
"The present invention overcomes this complication.",
"From the foregoing it can be seen that it is a primary object of the present invention to provide an improved optical focus acquisition system and method.",
"It is another object of the present invention to provide a system for focusing quickly onto the surface of an optical disk by commencing the focus operation as the disk is coming up to speed which facilitates final focusing when the disk is at speed.",
"These and other objects of the present invention will become more apparent when taken in conjunction with the following drawings wherein like characters indicate like parts and which drawings form a part of the present description.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of the preferred apparatus embodiment of the invention.",
"FIGS. 2A-2D are a group of waveforms illustrating the signals appearing at selected locations in the apparatus depicted in FIG. 1. FIGS. 3A and 3B, connected at the point labeled ○A , illustrate in flow chart form the operating sequence of the preferred method of the present invention.",
"DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 there is illustrated an optical focusing system for an optical recording disk 15.",
"The system utilizes a coherent light source, such as a laser 10, for directing a light beam through a prism set 11 and onto a mirror 12 which in turn directs the light beam through a focus actuator 13, containing an object lens 14, and onto the recording surface 15B of an optical recording disk 15.",
"The optical recording disk 15 generally, has an overcoat layer 15A which is used to protect the recording surface 15B.",
"Reflected light, from the optical recording disk, passes back through the object lens 14 to the mirror 12 and to the reflective surface 21, within the prism 11, which directs the reflected light to a lens 20 and onto a quad photodetector 16.",
"The photodetector 16 converts the light beam impinging thereon into two analog electrical signals, FOCUS ERROR and FOCUS GAIN by interconnecting each of the four photodetectors in a well-known manner.",
"The analog signals are coupled to a digital servo controller 17 through A/D converters 24 and 22, respectively.",
"The FOCUS ERROR signal is also an input to an analog servo 18.",
"The output signal from the analog servo 18 is applied to a first switch terminal of a SPST switch 19.",
"The switch 19 is activated by a signal from the servo controlled 17.",
"A two-input summer 28 has one +input connected to a second switch terminal of the switch 19 and the other +input connected to receive an output from the servo controller 17 via a D/A converter 26.",
"The signal from the summer 28 drives the focus actuator 13 towards or away from the disk 15.",
"Referring to FIG. 2C, from a start position the actuator 13 is pulsed with a voltage pulse 30 of magnitude and width to cause the actuator to move with a maximum acceleration (jump) towards a first position.",
"The pulses are generated by the servo controller 17.",
"Immediately thereafter a deceleration pulse 32 is applied to the actuator to cause the actuator to rest at the first position evidenced by the horizontal line 34.",
"At this point, focus has not been passed (determined by observing FOCUS GAIN FIG. 2A).",
"A second pulse 36 is applied, followed by a deceleration pulse 38 which causes the actuator to move quickly to a second rest position evidenced by the horizontal line 40.",
"As the actuator moved between the first position and the second position the desired focus positioned was passed as evidenced by the peak 50 in the FOCUS GAIN signal.",
"At this point, the actuator is impulsed with a pulse 42 driving the acutuator back towards the first position and with a deceleration pulse 44 to reach the position evidenced by the horizontal line 46.",
"At this position, the actuator passed the focus point again, as evidenced by the peak 52 in the FOCUS GAIN signal.",
"Thereafter, the servo controller 17 outputs a FOCUS RAMP signal to drive the focus actuator to the desired focus position.",
"As this is done, the FOCUS GAIN is shown increasing towards and past a first threshold level T 1 in response to a FOCUS RAMP signal, illustrated in FIG. 2C, driving in a downward ramp direction which corresponds to the focus actuator (object lens 14) being driven away from the recording surface 15B of the optical disk 15 and simultaneously, the FOCUS ERROR signal, illustrated in FIG. 2B, is shown increasing towards a negative peak value.",
"With the FOCUS GAIN passing the threshold, the FOCUS ERROR signal begins to reach its peak negative value indicating that the objective lens is being driven towards a correct focus position.",
"With the FOCUS ERROR signal changing from a negative value to a positive value and the FOCUS GAIN being at a maximum value the ramping operation is terminated and the focus servo is switched ON, as referenced by the step in the waveform of FIG. 2D, by a switching signal from the servo controller 17, which closes the switch 19.",
"Referring now to FIGS. 3A and 3B, which illustrate the operation method of the preferred apparatus embodiment in flow diagram form, the system is initialized in operation via the initialized variables block 200 which then moves the operating sequence to the question block 201 which requests whether focus is to be acquired while spinning up the disk.",
"If the answer is NO, the system goes to block 204 to achieve focus in the classical manner by following the flow along the line labeled ○A .",
"If the answer is YES, focus is initiated for the quick mode and the question block 202 is activated, sampling the motion of the disk to answer YES when the disk is in motion.",
"If the answer is NO, the question block 202 branches to block 203 which waits for the disk to start moving before outputting an inquiry to block 202.",
"When the disk is in motion, question block 202 will output a YES answer which will turn on the read laser per the action block 205.",
"If the read laser is not turned on as an answer to the questioning block 206, a NO branch will occur to a block 208 which will provide a false signal along the line terminating with an ○A .",
"That line will be picked up at the input to a question block 209.",
"The question asked will be is it OK to focus with the read laser off.",
"If the answer is NO, a branch will be taken to a report status block 215 indicating a fault status and the program will exit at block 216.",
"If the answer to the questioning block 209 is YES, focusing will be activated by stepping the objective lens (activator) to a start position as evidenced by action block 210.",
"With the objective lens at the start position it is jumped to a first position by action block 220 and the gain is monitored to determine if the lens moved past the focus position.",
"This question is asked in block 222.",
"If the answer is NO the lens is jumped again.",
"This process continues until the answer is YES.",
"The lens is then jumped back, by action block 224.",
"The magnitude of the jump varies for different systems and is ideally adjusted to provide the required crossing of focus within two jumps.",
"Next, the lens will be ramped away from the disk until the focus again is at some value below a threshold.",
"In the preferred embodiment, the threshold value was a gain of 80.",
"This is reflected in the action block 211.",
"Once achieved, the system moves to the question block 212 which questions whether the gain is below the threshold value and additionally whether the FOCUS ERROR signal is below a predetermined threshold.",
"If the answer is YES, the system branches to block 213 which sets the FOCUS GAIN at some nominal value and locks the focus servo into its fine focusing mode.",
"Once accomplished, a question block 214 questions whether focus has been achieved.",
"If the answer is NO, the system branches to a question and action box 217 which permits three retries for focus before moving to a report status mode 215 (reporting a default).",
"If the system is in focus the report status mode 215 is entered indicating the achievement of the fine focus.",
"Moving back to the questioning block 212, if the FOCUS ERROR signal is greater than a threshold value, in the preferred embodiment the threshold is 128, a NO response is achieved from the question block 212 and the program branches back to the input to the question block 211 until the FOCUS ERROR signal reaches a value which is below 128.",
"In a like manner, if the FOCUS GAIN is greater than 80, the program branches back to the input to action block 211 and ramps the lens further away from the disk until the FOCUS GAIN is less than 80.",
"The flow diagram steps shown in FIGS. 3A and 3B can be implemented with a software program for driving the servo controller 17.",
"In conclusion, there has been described a system (apparatus) and a method for quickly acquiring focus onto the recording surface of an optical disk by focusing the optical system onto the recording medium as the disk starts spinning and by jumping the actuator to a position close to the final focus position while the disk is reaching operational speed and by switching in the servo to quickly focus onto the recording surface rather than the protective surface.",
"While there has been shown what are considered to be the preferred embodiments of the invention, it will be manifest that many modifications may be made therein without departing from the essential spirit of the invention.",
"It is intended, therefore, in the annexed claims to cover all such changes and modifications as may fall within the true scope of the invention."
] |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan application serial no. 90113549, filed on Jun. 5, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The present invention relates to a bonding pad structure. More particularly, the present invention relates to a bonding pad structure having detached current conduction regions and mechanical support regions.
[0004] 2. Description of Related Art
[0005] In the front stage of fabricating semiconductor devices, a plurality of optical masks is used to pattern out the active regions, gate structures, metallic layers, source/drain contacts, circuit pattern of multi-level interconnects and bonding pad windows. Due to the rapid increase in the level of integration of semiconductor devices, functional capacity and data processing speed, the number of signaling points on a semiconductor component increases considerably. As the number of contact points increases, the number of corresponding bonding pads required is also increased. After the formation of bonding pads, the integrated circuit chip must be packaged. In other words, the signal points and bonding pads on the silicon chip must connect electrically with a lead frame via metallic wires, a process known as wire-bonding. A wire-bonding operation links each bonding pad on a semiconductor chip with an inner lead of the lead frame using a fine metallic wire (30-50μm). Hence, electrical signal generated inside the semiconductor chip can be transmitted to circuits outside the package. The bonding pad on the semiconductor chip serves as a first bonding point while the inner lead of the lead frame serves as a second bonding point. During wire bonding, one end of a metallic wire is melted into a spherical blob and then the spherical blob is pressed onto the bonding pad to form a weld with the aid of an ultrasonic vibration. The metallic wire is pulled along a pre-defined path towards a corresponding inner lead position on the lead frame. Thereafter, the other end of the wire is bonded to the inner lead. Finally, excess metallic wire is pulled off from the bonded inner lead. By repeating the aforementioned wire bonding process, the entire package is connected. Because ultrasonic vibration is employed in the bonding of a metallic wire onto the bonding pad, passivation layer or dielectric layer surrounding the bonding pad regions may crack due to stress concentration. In addition, the difference in coefficient of thermal expansion (CTE) between epoxy resin and the silicon chip during subsequent packaging may cause a further widening of the cracks already formed in the passivation layer or the dielectric layer.
[0006] One method of reducing uneven stress distribution within a semiconductor package is to form a plurality of bonding pad metallic layers in the desired bonding pad locations. The bonding pad metallic layers are similar in shape to bonding pads during interconnect fabrication. Plugs having a circular, rectangular or other shape arranged in a pre-defined array pattern are used to connect between the bonding pad metallic layers or the bonding pad metallic layer and the bonding pad. The bottommost layer also connects with the silicon substrate so that stress is evenly distributed over the entire wafer by the silicon substrate. Hence, the silicon wafer is less vulnerable to damages during subsequent processing.
[0007] Conventionally, a metallic plug is formed by conducting a plasma etching operation to remove a portion of the insulation layer and expose a portion of the bonding pad metallic layer and then refilling the opening with a metal. During a plasma etching operation, a portion of the electrical charges in the plasma may be transferred to the bonding pad metallic layer. These electrical charges may be transmitted to the devices via the conductive path between the bonding pad metallic layer and the devices.
[0008] In addition, a fixed number of plugs must be provided between the bonding pads and the bonding pad metallic layers or between the bonding pad metallic layers to ensure sufficient mechanical support for the bonding pads. However, the conductive current transmitted to the devices resulting from electric charges in the plasma is proportional to the number of plugs used. In other words, the larger number of metallic plugs used, the larger will be the total amount of electric charges collected by various bonding pad metallic layers. The flow of a large conduction current into the device may lead to device failure and a lowering of production yield.
[0009] Nevertheless, reducing conduction current by using fewer plugs between the bonding pad and the silicon substrate often leads to a drop in mechanical strength of the bonding pad. Damages rendered by subsequent processing may result in a higher production cost.
[0010] A method capable of increasing mechanical strength of the bonding pad without increasing corresponding conductive current is unavailable at present. Hence, only a compromised solution involving a balance between an acceptable conduction current, a minimum mechanical support for bonding pad and production cost can be sought.
SUMMARY OF THE INVENTION
[0011] Accordingly, one object of the present invention is to provide a bonding pad structure having a detached current conduction structure and mechanical support structure. The detached current conduction structure and mechanical support structure reduces the quantity of electric charges flowing to devices during etching but increases the mechanical strength of the bonding pad. Ultimately, product yield is increased and failure rate of subsequently processed silicon wafer is reduced.
[0012] To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a bonding pad structure. The bonding pad structure includes independently built current conduction structure and mechanical support structure between a bonding pad layer and a substrate. The current conduction structure is constructed using a plurality of serially connected conductive metallic layers, each at a different height between the bonding pad layer and the substrate. The conductive metallic layers connect with each other via a plurality of plugs. At least one of the conductive metallic layers connects electrically with a portion of the device in the substrate by a signal conduction line. The mechanical support structure is constructed using a plurality of serially connected supportive metallic layers each at a different height between the bonding pad layer and the substrate. The supportive metallic layers connect with each other via a plurality of plugs. Furthermore, the mechanical support structure connects with a non-device section of the substrate so that stresses on the bonding pads are distributed evenly through the substrate.
[0013] In this invention, since cross-sectional area of the conductive metallic layer in the current conduction structure is smaller than the bonding pad layer, the number of plugs connected to various conductive metallic layers can be reduced. Hence, current transmitted to the device via the current conduction structure will not exceed the permitted charge current during plasma etching. In other words, device breakdown due to excess charge flow is prevented leading to a higher yield and a lower production cost.
[0014] In addition, mechanical strength of the bonding pads is increased because both the mechanical support structure connected to the bonding pad layer and the current conduction structure are used in this invention. Since the mechanical support structure and the current conduction structure are connected together via the bonding pad layer only, electric charges absorbed when forming the plugs above the supporting metallic layer will not transmit to the current conduction structure. In this way, plug density can be increased to improve supportive strength of bonding pads. In the meantime, excessive current flowing to devices leading to device failures can be prevented.
[0015] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,
[0017] [0017]FIG. 1 is a sketch showing a bonding pad structure fabricated according to a first preferred embodiment of this invention;
[0018] [0018]FIG. 2 is a cross-sectional view of the bonding pad structure as shown in FIG. 1;
[0019] FIGS. 3 is a sketch showing a bonding pad structure fabricated according to a second preferred embodiment of this invention; and
[0020] FIGS. 4 is a sketch showing a bonding pad structure fabricated according to a third preferred embodiment of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
[0022] [0022]FIG. 1 is a sketch showing a bonding pad structure fabricated according to a first preferred embodiment of this invention. As shown in FIG. 1, the bonding structure includes a substrate 100 , a mechanical support structure 112 , a current conduction structure 114 and a bonding pad layer 116 . The bonding pad layer 116 is above the substrate 100 . The current conduction structure 114 is attached to the bonding pad layer 116 between the bonding pad layer 116 and the substrate 100 . Similarly, the mechanical support structure 112 is also attached to the bonding pad layer 116 between the bonding pad layer 116 and the substrate 100 . The substrate 100 can be a semiconductor substrate or a substrate with multi-layered interconnects therein.
[0023] The current conduction structure 114 and the mechanical support structure 112 are two detached structures connected only by the bonding layer 116 . Furthermore, an insulation layer 106 is formed between the current conduction structure 114 and the mechanical support structure 112 . The insulation layer 106 comprises more than one insulating material layer and the insulating material is silicon nitride, silicon oxide or silicon oxynitride.
[0024] The current conduction structure 114 includes a plurality of serially connected metallic layers 104 a , 104 b , 104 c each located at a different height level between the bonding pad layer 116 and the substrate 100 . The conductive metallic layers 104 a , 104 b , 104 c are linked together via plugs 110 a and 110 b , respectively. The conductive metallic layer 104 c and the bonding pad layer 116 are linked together via plugs 110 c . The conductive metallic layer 104 a is in contact with the substrate 100 so that the current conduction structure 114 actually connects the bonding pad layer 116 and the substrate 100 together. The conductive metallic layers 104 a , 104 b , 104 c connect electrically with a signal line (not shown). Hence, the conductive metallic layers are electrically connected to a device section (not shown) on substrate 100 . The conductive metallic layers can be local metallic interconnects, for example.
[0025] The mechanical support structure 112 includes a plurality of serially connected support metallic layers 102 a , 102 b and 102 c , each located at a different height level between the bonding pad layer 116 and the substrate 100 . The support metallic layers 102 a , 102 b , 102 c are linked together via plugs 108 a and 108 b . The support metallic layer 102 c and the bonding pad layer 116 are linked together via plugs 108 c . The support metallic layer 102 a and the substrate 100 are in contact with each other to form the mechanical support structure 112 between the bonding pad layer 116 and the substrate 100 . The support metallic layers can be local metallic interconnects, for example.
[0026] Since the bottom conductive metallic layer 104 a of the current conduction structure 114 and the bottom support metallic layer 102 a of the mechanical support structure 112 are formed on the substrate 100 , stress on the bonding pad layer 116 is transmitted to the conductive metallic layer 104 a and the support metallic layer 102 a via the current conduction structure 114 and the mechanical support structure 112 , respectively, and finally the stress is transmitted to the substrate 100 via the conductive metallic layer 104 a and the support metallic layer 102 a . Ultimately, stress is evenly distributed across the entire substrate 100 .
[0027] Because cross-sectional area of the conductive metallic layers 104 a , 104 b , 104 c in the current conduction structure 114 is smaller than that of a conventional bonding pad metallic layer, the number of plugs 110 a , 110 b , 110 c attached to various conductive metallic layers 104 a , 104 b , 104 c is smaller than the number of plugs attached to a conventional bonding pad metallic layer. Hence, overall in-processing current delivered to the device section of the substrate 100 via the current conduction structure 114 is greatly reduced. Ultimately, product yield is increased and production cost is lowered.
[0028] Besides the capacity to conduct current between the bonding pad layer 116 and the substrate 100 , the current conduction structure 114 also has some mechanical support capacity. Through a special patterning of the plugs, the current conduction structure 114 can increase plug density of the mechanical support structure 112 so that bonding pad 116 has the capacity to support a greater load. In addition, the current conduction structure 114 and the mechanical support structure 112 are detached structures. Hence, an increase in plug density for the mechanical support structure 112 will not lead to an increase in current transmitted to the device section during plasma processing.
[0029] Furthermore, cross-sectional profile of the bonding pad 116 , the conductive metallic layers 104 a , 104 b , 104 c and the support metallic layers 102 a , 102 b , 102 c can have any shape as corresponds to actual processing requirements. Similarly, cross-sectional profile of various plugs including 108 a , 108 b , 108 c , 110 a , 110 b , and 110 c can have any shape. Moreover, the plugs can be arranged in whatever pattern is suitable for a particular application.
[0030] [0030]FIG. 2 is a cross-sectional view of the bonding pad structure as shown in FIG. 1. As shown in FIG. 2, the bonding pad layer is rectangular, the plugs 208 and 210 have a circular top and the plugs 208 and 210 form a rectangular array. The aforementioned arrangement is used as an illustration only and is by no means to be construed as a limitation of this invention.
[0031] Because the conductive metallic layer 204 and the support metallic layer 202 correspond very much with the bonding pad layer, the number of plugs 210 distributed across the conductive metallic layers 204 is much smaller than the number of plugs 208 distributed across the support metallic layer 202 when the conductive metallic layer 204 has an area much smaller than the support metallic layer 202 . The number of paths available for charges to flow into the devices is greatly reduced in the process of forming the plugs 210 . Since the current flowing to the devices via the conductive metallic layer 204 will not exceed the capacity of the devices, device failure is reduced and product yield is increased.
[0032] In addition, area at the top of the support metallic layer 202 is only slightly smaller than that of a conventional bonding pad metallic layer. Moreover, the plugs 210 on the conductive metallic layer 204 have some capacity for supporting loads and hence the bonding pad stress supporting capacity in this invention is almost identical to that of a conventional design. Furthermore, the support metallic layer 202 has no direct contact with the device section on the substrate 200 . Therefore, the number of plugs 208 on the support metallic layer 202 can be increased to support higher stress at the bonding pad.
[0033] Shape and size of the conductive metallic layers and the support metallic layers can be different from the ones shown in FIG. 2. For example, the conductive metallic layer can have an area greater than the support metallic layer or identical to the support metallic layer.
[0034] In the first embodiment, although a current conduction structure with three conductive metallic layers and a mechanical support structure with three support metallic layer are shown, there is no limitation to the total number of layers used. In general, a current conduction structure can have a multiple of conductive metallic layers and a mechanical support structure can have a multiple of support metallic layers between the bonding pad layer and the substrate.
[0035] FIGS. 3 is a sketch showing a bonding pad structure fabricated according to a second preferred embodiment of this invention. In the first embodiment, the substrate is in direct contact with a conductive metallic layer and a support metallic layer. In the second embodiment, however, the conductive metallic layer and the support metallic layer are in contact with the substrate via plugs. The following is a detailed description of the second embodiment of this invention.
[0036] As shown in FIG. 3, the bonding structure includes a substrate 300 , a mechanical support structure 312 , a current conduction structure 314 and a bonding pad layer 316 . The bonding pad layer 316 is above the substrate 300 . The current conduction structure 314 is attached to the bonding pad layer 316 between the bonding pad layer 316 and the substrate 300 . Similarly, the mechanical support structure 312 is also attached to the bonding pad layer 316 between the bonding pad layer 316 and the substrate 300 . The substrate 300 can be a semiconductor substrate or a substrate with multi-layered interconnects therein.
[0037] The current conduction structure 314 and the mechanical support structure 312 are two detached structures connected only by the bonding layer 316 . Furthermore, an insulation layer 306 is formed between the current conduction structure 314 and the mechanical support structure 312 . The insulation layer 306 comprises more than one insulating material layer and the insulating material is silicon nitride, silicon oxide or silicon oxynitride.
[0038] The current conduction structure 314 includes a plurality of serially connected metallic layers 304 a , 304 b and 304 c , each located at a different height level between the bonding pad layer 316 and the substrate 300 . The conductive metallic layers 304 a , 304 b , 304 c are linked together via plugs 310 b and 310 c , respectively. The conductive metallic layer 304 c and the bonding pad layer 316 are linked together via plugs 310 d . The conductive metallic layer 304 a and the substrate 300 are linked together via plugs 310 a to form a current conduction structure 314 between the bonding pad layer 316 and the substrate 300 . The conductive metallic layers 304 a , 304 b , 304 c connect electrically with a signal line (not shown). Hence, the conductive metallic layers are electrically connected to a device section (not shown) on substrate 300 . The conductive metallic layers 304 a , 304 b and 304 c can be local metallic interconnects, for example.
[0039] The mechanical support structure 312 includes a plurality of serially connected support metallic layers 302 a , 302 b and 302 c , each located at a different height level between the bonding pad layer 316 and the substrate 300 . The support metallic layers 302 a , 302 b , 302 c are linked together via plugs 308 b and 308 c . The support metallic layer 302 c and the bonding pad layer 316 are linked together via plugs 308 d . The support metallic layer 302 a and the substrate 300 are linked together via plugs 308 a to form a mechanical support structure 314 between the bonding pad layer 316 and the substrate 300 . The support metallic layers can be a local metallic interconnects, for example.
[0040] Since the plugs 310 a of the current conduction structure 314 and the plugs 308 a of the mechanical support structure 312 are formed on the substrate 300 , stress on the bonding pad layer 316 is transmitted to the plugs 310 a and the plugs 308 a via the current conduction structure 314 and the mechanical support structure 312 , respectively. Finally, the stress is transmitted to the substrate 300 via the plugs 310 a and 308 a so that stress is evenly distributed across the entire substrate 100 .
[0041] Because cross-sectional area of the conductive metallic layers 304 a , 304 b , 304 c in the current conduction structure 314 is smaller than a conventional bonding pad metallic layer, the number of plugs 310 b , 310 c , 310 d attached to various conductive metallic layers 304 a , 304 b , 304 c is smaller than the number of plugs attached to a conventional bonding pad metallic layer. Hence, overall in-processing current delivered to the device section of the substrate 300 via the current conduction structure 314 is greatly reduced. Ultimately, product yield is increased and production cost is lowered.
[0042] Besides the capacity to conduct current between the bonding pad layer 316 and the substrate 300 , the current conduction structure 314 also has some mechanical support capacity. Through a special patterning of the plugs 310 a , 310 b , 310 c and 310 d , the current conduction structure 314 can increase plug density of the mechanical support structure 312 so that bonding pad 316 has the capacity to support a greater load. In addition, the current conduction structure 314 and the mechanical support structure 312 are detached structures. Hence, an increase in plug density for the mechanical support structure 312 will not lead to an increase in current transmitted to the device section during plasma processing.
[0043] Furthermore, cross-sectional profile of the bonding pad 316 , the conductive metallic layers 304 a , 304 b , 304 c and the support metallic layers 302 a , 302 b , 302 c can have any shape according to actual processing requirements. Similarly, cross-sectional profiles of various plugs including 308 a , 308 b , 308 c , 308 d , 310 a , 310 b , 310 c and 310 d can have any shape. Moreover, the plugs can be arranged in whatever pattern is suitable for a particular application.
[0044] In the second embodiment, although a current conduction structure with three conductive metallic layers and a mechanical support structure with three support metallic layer are shown, there is no limitation to the total number of layers used. In general, a current conduction structure can have a multiple of conductive metallic layers and a mechanical support structure can have a multiple of support metallic layers between the bonding pad layer and the substrate.
[0045] FIGS. 4 is a sketch showing a bonding pad structure fabricated according to a third preferred embodiment of this invention. In the first embodiment, the number of conductive metallic layers and the number of support metallic layers are identical. In the third embodiment, however, the number of conductive metallic layers is different from the number of support metallic layers. The following is a detailed description of the second embodiment of this invention.
[0046] As shown in FIG. 4, the bonding structure includes a substrate 400 , a mechanical support structure 412 , a current conduction structure 414 and a bonding pad layer 416 . The bonding pad layer 416 is above the substrate 400 . The current conduction structure 414 is attached to the bonding pad layer 416 between the bonding pad layer 416 and the substrate 400 . Similarly, the mechanical support structure 412 is also attached to the bonding pad layer 416 between the bonding pad layer 416 and the substrate 400 . The substrate 400 can be a semiconductor substrate or a substrate with multi-layered interconnects therein.
[0047] The current conduction structure 414 and the mechanical support structure 412 are two detached structures connected only by the bonding layer 416 . Furthermore, an insulation layer 406 is formed between the current conduction structure 414 and the mechanical support structure 412 . The insulation layer 406 comprises of more than one insulating material layer and the insulating material is silicon nitride, silicon oxide or silicon oxynitride.
[0048] The current conduction structure 414 includes a plurality of serially connected metallic layers 404 a and 404 b , each located at a different height level between the bonding pad layer 416 and the substrate 400 . The conductive metallic layers 404 a , 404 b are linked together via plugs 410 a . The conductive metallic layer 404 b and the bonding pad layer 416 are linked together via plugs 410 b . The conductive metallic layer 404 a is in contact with the substrate 400 so that the current conduction structure 414 actually connects the bonding pad layer 416 and the substrate 400 together. The conductive metallic layers 404 a , 404 b connect electrically with a signal line (not shown). Hence, the conductive metallic layers are electrically connected to a device section (not shown) on substrate 400 . The conductive metallic layers can be local metallic interconnects, for example.
[0049] The mechanical support structure 412 includes a plurality of serially connected support metallic layers 402 a , 402 b , 402 c each located at a different height level between the bonding pad layer 416 and the substrate 400 . The support metallic layers 402 a , 402 b , 402 c are linked together via plugs 408 a and 408 b . The support metallic layer 402 c and the bonding pad layer 416 are linked together via plugs 408 c . The support metallic layer 402 a and the substrate 400 are in contact with each other to form the mechanical support structure 412 between the bonding pad layer 416 and the substrate 400 . The support metallic layers can be local metallic interconnects, for example.
[0050] Since the bottom conductive metallic layer 404 a of the current conduction structure 414 and the bottom support metallic layer 402 a of the mechanical support structure 412 are formed on the substrate 400 , stress on the bonding pad layer 416 is transmitted to the conductive metallic layer 404 a and the support metallic layer 402 a via the current conduction structure 414 and the mechanical support structure 412 , respectively. The stress is transmitted to the substrate 400 via the conductive metallic layer 404 a and the support metallic layer 402 a . Ultimately, stress is evenly distributed across the entire substrate 400 .
[0051] When the cross-sectional area of the conductive metallic layers in the current conduction structure 414 is much smaller than the cross-sectional area of the support metallic layers in the mechanical support structure 412 , the number of conductive metallic layer in the current conduction structure 414 cannot be identical to the number of support metallic layer in the mechanical support structure 412 . This is because the purpose of the current conduction structure 414 is to provide an electrical path between the bonding pad layer and the substrate devices. The stress supporting capacity of the current conduction structure 414 is of secondary importance. The effect of having a number of conductive metallic layers in the current conduction structure that differs from the number of support metallic layer is relatively small.
[0052] Furthermore, cross-sectional profile of the bonding pad 416 , the conductive metallic layers 404 a , 404 b and the support metallic layers 402 a , 402 b , 402 c can have any shape according to actual processing requirements. Similarly, cross-sectional profile of various plugs including 408 a , 408 b , 408 c , 410 a , and 410 b can have any shape. Moreover, the plugs can be arranged in whatever pattern suitable for a particular application.
[0053] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. | A bonding pad structure. The bonding pad structure includes independently built current conduction structure and mechanical support structure between a bonding pad layer and a substrate. The current conduction structure is constructed using a plurality of serially connected conductive metallic layers each at a different height between the bonding pad layer and the substrate. The conductive metallic layers connect with each other via a plurality of plugs. At least one of the conductive metallic layers connects electrically with a portion of the device in the substrate by a signal conduction line. The mechanical support structure is constructed using a plurality of serially connected supportive metallic layers each at a different height between the bonding pad layer and the substrate. The supportive metallic layers connect with each other via a plurality of plugs. Furthermore, the mechanical support structure connects with a non-device section of the substrate so that stresses on the bonding pads are distributed evenly through the substrate. | Briefly outline the background technology and the problem the invention aims to solve. | [
"CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the priority benefit of Taiwan application serial no. 90113549, filed on Jun. 5, 2001.",
"BACKGROUND OF THE INVENTION [0002] 1.",
"Field of Invention [0003] The present invention relates to a bonding pad structure.",
"More particularly, the present invention relates to a bonding pad structure having detached current conduction regions and mechanical support regions.",
"[0004] 2.",
"Description of Related Art [0005] In the front stage of fabricating semiconductor devices, a plurality of optical masks is used to pattern out the active regions, gate structures, metallic layers, source/drain contacts, circuit pattern of multi-level interconnects and bonding pad windows.",
"Due to the rapid increase in the level of integration of semiconductor devices, functional capacity and data processing speed, the number of signaling points on a semiconductor component increases considerably.",
"As the number of contact points increases, the number of corresponding bonding pads required is also increased.",
"After the formation of bonding pads, the integrated circuit chip must be packaged.",
"In other words, the signal points and bonding pads on the silicon chip must connect electrically with a lead frame via metallic wires, a process known as wire-bonding.",
"A wire-bonding operation links each bonding pad on a semiconductor chip with an inner lead of the lead frame using a fine metallic wire (30-50μm).",
"Hence, electrical signal generated inside the semiconductor chip can be transmitted to circuits outside the package.",
"The bonding pad on the semiconductor chip serves as a first bonding point while the inner lead of the lead frame serves as a second bonding point.",
"During wire bonding, one end of a metallic wire is melted into a spherical blob and then the spherical blob is pressed onto the bonding pad to form a weld with the aid of an ultrasonic vibration.",
"The metallic wire is pulled along a pre-defined path towards a corresponding inner lead position on the lead frame.",
"Thereafter, the other end of the wire is bonded to the inner lead.",
"Finally, excess metallic wire is pulled off from the bonded inner lead.",
"By repeating the aforementioned wire bonding process, the entire package is connected.",
"Because ultrasonic vibration is employed in the bonding of a metallic wire onto the bonding pad, passivation layer or dielectric layer surrounding the bonding pad regions may crack due to stress concentration.",
"In addition, the difference in coefficient of thermal expansion (CTE) between epoxy resin and the silicon chip during subsequent packaging may cause a further widening of the cracks already formed in the passivation layer or the dielectric layer.",
"[0006] One method of reducing uneven stress distribution within a semiconductor package is to form a plurality of bonding pad metallic layers in the desired bonding pad locations.",
"The bonding pad metallic layers are similar in shape to bonding pads during interconnect fabrication.",
"Plugs having a circular, rectangular or other shape arranged in a pre-defined array pattern are used to connect between the bonding pad metallic layers or the bonding pad metallic layer and the bonding pad.",
"The bottommost layer also connects with the silicon substrate so that stress is evenly distributed over the entire wafer by the silicon substrate.",
"Hence, the silicon wafer is less vulnerable to damages during subsequent processing.",
"[0007] Conventionally, a metallic plug is formed by conducting a plasma etching operation to remove a portion of the insulation layer and expose a portion of the bonding pad metallic layer and then refilling the opening with a metal.",
"During a plasma etching operation, a portion of the electrical charges in the plasma may be transferred to the bonding pad metallic layer.",
"These electrical charges may be transmitted to the devices via the conductive path between the bonding pad metallic layer and the devices.",
"[0008] In addition, a fixed number of plugs must be provided between the bonding pads and the bonding pad metallic layers or between the bonding pad metallic layers to ensure sufficient mechanical support for the bonding pads.",
"However, the conductive current transmitted to the devices resulting from electric charges in the plasma is proportional to the number of plugs used.",
"In other words, the larger number of metallic plugs used, the larger will be the total amount of electric charges collected by various bonding pad metallic layers.",
"The flow of a large conduction current into the device may lead to device failure and a lowering of production yield.",
"[0009] Nevertheless, reducing conduction current by using fewer plugs between the bonding pad and the silicon substrate often leads to a drop in mechanical strength of the bonding pad.",
"Damages rendered by subsequent processing may result in a higher production cost.",
"[0010] A method capable of increasing mechanical strength of the bonding pad without increasing corresponding conductive current is unavailable at present.",
"Hence, only a compromised solution involving a balance between an acceptable conduction current, a minimum mechanical support for bonding pad and production cost can be sought.",
"SUMMARY OF THE INVENTION [0011] Accordingly, one object of the present invention is to provide a bonding pad structure having a detached current conduction structure and mechanical support structure.",
"The detached current conduction structure and mechanical support structure reduces the quantity of electric charges flowing to devices during etching but increases the mechanical strength of the bonding pad.",
"Ultimately, product yield is increased and failure rate of subsequently processed silicon wafer is reduced.",
"[0012] To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a bonding pad structure.",
"The bonding pad structure includes independently built current conduction structure and mechanical support structure between a bonding pad layer and a substrate.",
"The current conduction structure is constructed using a plurality of serially connected conductive metallic layers, each at a different height between the bonding pad layer and the substrate.",
"The conductive metallic layers connect with each other via a plurality of plugs.",
"At least one of the conductive metallic layers connects electrically with a portion of the device in the substrate by a signal conduction line.",
"The mechanical support structure is constructed using a plurality of serially connected supportive metallic layers each at a different height between the bonding pad layer and the substrate.",
"The supportive metallic layers connect with each other via a plurality of plugs.",
"Furthermore, the mechanical support structure connects with a non-device section of the substrate so that stresses on the bonding pads are distributed evenly through the substrate.",
"[0013] In this invention, since cross-sectional area of the conductive metallic layer in the current conduction structure is smaller than the bonding pad layer, the number of plugs connected to various conductive metallic layers can be reduced.",
"Hence, current transmitted to the device via the current conduction structure will not exceed the permitted charge current during plasma etching.",
"In other words, device breakdown due to excess charge flow is prevented leading to a higher yield and a lower production cost.",
"[0014] In addition, mechanical strength of the bonding pads is increased because both the mechanical support structure connected to the bonding pad layer and the current conduction structure are used in this invention.",
"Since the mechanical support structure and the current conduction structure are connected together via the bonding pad layer only, electric charges absorbed when forming the plugs above the supporting metallic layer will not transmit to the current conduction structure.",
"In this way, plug density can be increased to improve supportive strength of bonding pads.",
"In the meantime, excessive current flowing to devices leading to device failures can be prevented.",
"[0015] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0016] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification.",
"The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.",
"In the drawings, [0017] [0017 ]FIG. 1 is a sketch showing a bonding pad structure fabricated according to a first preferred embodiment of this invention;",
"[0018] [0018 ]FIG. 2 is a cross-sectional view of the bonding pad structure as shown in FIG. 1;",
"[0019] FIGS. 3 is a sketch showing a bonding pad structure fabricated according to a second preferred embodiment of this invention;",
"and [0020] FIGS. 4 is a sketch showing a bonding pad structure fabricated according to a third preferred embodiment of this invention.",
"DESCRIPTION OF THE PREFERRED EMBODIMENTS [0021] Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.",
"Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.",
"[0022] [0022 ]FIG. 1 is a sketch showing a bonding pad structure fabricated according to a first preferred embodiment of this invention.",
"As shown in FIG. 1, the bonding structure includes a substrate 100 , a mechanical support structure 112 , a current conduction structure 114 and a bonding pad layer 116 .",
"The bonding pad layer 116 is above the substrate 100 .",
"The current conduction structure 114 is attached to the bonding pad layer 116 between the bonding pad layer 116 and the substrate 100 .",
"Similarly, the mechanical support structure 112 is also attached to the bonding pad layer 116 between the bonding pad layer 116 and the substrate 100 .",
"The substrate 100 can be a semiconductor substrate or a substrate with multi-layered interconnects therein.",
"[0023] The current conduction structure 114 and the mechanical support structure 112 are two detached structures connected only by the bonding layer 116 .",
"Furthermore, an insulation layer 106 is formed between the current conduction structure 114 and the mechanical support structure 112 .",
"The insulation layer 106 comprises more than one insulating material layer and the insulating material is silicon nitride, silicon oxide or silicon oxynitride.",
"[0024] The current conduction structure 114 includes a plurality of serially connected metallic layers 104 a , 104 b , 104 c each located at a different height level between the bonding pad layer 116 and the substrate 100 .",
"The conductive metallic layers 104 a , 104 b , 104 c are linked together via plugs 110 a and 110 b , respectively.",
"The conductive metallic layer 104 c and the bonding pad layer 116 are linked together via plugs 110 c .",
"The conductive metallic layer 104 a is in contact with the substrate 100 so that the current conduction structure 114 actually connects the bonding pad layer 116 and the substrate 100 together.",
"The conductive metallic layers 104 a , 104 b , 104 c connect electrically with a signal line (not shown).",
"Hence, the conductive metallic layers are electrically connected to a device section (not shown) on substrate 100 .",
"The conductive metallic layers can be local metallic interconnects, for example.",
"[0025] The mechanical support structure 112 includes a plurality of serially connected support metallic layers 102 a , 102 b and 102 c , each located at a different height level between the bonding pad layer 116 and the substrate 100 .",
"The support metallic layers 102 a , 102 b , 102 c are linked together via plugs 108 a and 108 b .",
"The support metallic layer 102 c and the bonding pad layer 116 are linked together via plugs 108 c .",
"The support metallic layer 102 a and the substrate 100 are in contact with each other to form the mechanical support structure 112 between the bonding pad layer 116 and the substrate 100 .",
"The support metallic layers can be local metallic interconnects, for example.",
"[0026] Since the bottom conductive metallic layer 104 a of the current conduction structure 114 and the bottom support metallic layer 102 a of the mechanical support structure 112 are formed on the substrate 100 , stress on the bonding pad layer 116 is transmitted to the conductive metallic layer 104 a and the support metallic layer 102 a via the current conduction structure 114 and the mechanical support structure 112 , respectively, and finally the stress is transmitted to the substrate 100 via the conductive metallic layer 104 a and the support metallic layer 102 a .",
"Ultimately, stress is evenly distributed across the entire substrate 100 .",
"[0027] Because cross-sectional area of the conductive metallic layers 104 a , 104 b , 104 c in the current conduction structure 114 is smaller than that of a conventional bonding pad metallic layer, the number of plugs 110 a , 110 b , 110 c attached to various conductive metallic layers 104 a , 104 b , 104 c is smaller than the number of plugs attached to a conventional bonding pad metallic layer.",
"Hence, overall in-processing current delivered to the device section of the substrate 100 via the current conduction structure 114 is greatly reduced.",
"Ultimately, product yield is increased and production cost is lowered.",
"[0028] Besides the capacity to conduct current between the bonding pad layer 116 and the substrate 100 , the current conduction structure 114 also has some mechanical support capacity.",
"Through a special patterning of the plugs, the current conduction structure 114 can increase plug density of the mechanical support structure 112 so that bonding pad 116 has the capacity to support a greater load.",
"In addition, the current conduction structure 114 and the mechanical support structure 112 are detached structures.",
"Hence, an increase in plug density for the mechanical support structure 112 will not lead to an increase in current transmitted to the device section during plasma processing.",
"[0029] Furthermore, cross-sectional profile of the bonding pad 116 , the conductive metallic layers 104 a , 104 b , 104 c and the support metallic layers 102 a , 102 b , 102 c can have any shape as corresponds to actual processing requirements.",
"Similarly, cross-sectional profile of various plugs including 108 a , 108 b , 108 c , 110 a , 110 b , and 110 c can have any shape.",
"Moreover, the plugs can be arranged in whatever pattern is suitable for a particular application.",
"[0030] [0030 ]FIG. 2 is a cross-sectional view of the bonding pad structure as shown in FIG. 1. As shown in FIG. 2, the bonding pad layer is rectangular, the plugs 208 and 210 have a circular top and the plugs 208 and 210 form a rectangular array.",
"The aforementioned arrangement is used as an illustration only and is by no means to be construed as a limitation of this invention.",
"[0031] Because the conductive metallic layer 204 and the support metallic layer 202 correspond very much with the bonding pad layer, the number of plugs 210 distributed across the conductive metallic layers 204 is much smaller than the number of plugs 208 distributed across the support metallic layer 202 when the conductive metallic layer 204 has an area much smaller than the support metallic layer 202 .",
"The number of paths available for charges to flow into the devices is greatly reduced in the process of forming the plugs 210 .",
"Since the current flowing to the devices via the conductive metallic layer 204 will not exceed the capacity of the devices, device failure is reduced and product yield is increased.",
"[0032] In addition, area at the top of the support metallic layer 202 is only slightly smaller than that of a conventional bonding pad metallic layer.",
"Moreover, the plugs 210 on the conductive metallic layer 204 have some capacity for supporting loads and hence the bonding pad stress supporting capacity in this invention is almost identical to that of a conventional design.",
"Furthermore, the support metallic layer 202 has no direct contact with the device section on the substrate 200 .",
"Therefore, the number of plugs 208 on the support metallic layer 202 can be increased to support higher stress at the bonding pad.",
"[0033] Shape and size of the conductive metallic layers and the support metallic layers can be different from the ones shown in FIG. 2. For example, the conductive metallic layer can have an area greater than the support metallic layer or identical to the support metallic layer.",
"[0034] In the first embodiment, although a current conduction structure with three conductive metallic layers and a mechanical support structure with three support metallic layer are shown, there is no limitation to the total number of layers used.",
"In general, a current conduction structure can have a multiple of conductive metallic layers and a mechanical support structure can have a multiple of support metallic layers between the bonding pad layer and the substrate.",
"[0035] FIGS. 3 is a sketch showing a bonding pad structure fabricated according to a second preferred embodiment of this invention.",
"In the first embodiment, the substrate is in direct contact with a conductive metallic layer and a support metallic layer.",
"In the second embodiment, however, the conductive metallic layer and the support metallic layer are in contact with the substrate via plugs.",
"The following is a detailed description of the second embodiment of this invention.",
"[0036] As shown in FIG. 3, the bonding structure includes a substrate 300 , a mechanical support structure 312 , a current conduction structure 314 and a bonding pad layer 316 .",
"The bonding pad layer 316 is above the substrate 300 .",
"The current conduction structure 314 is attached to the bonding pad layer 316 between the bonding pad layer 316 and the substrate 300 .",
"Similarly, the mechanical support structure 312 is also attached to the bonding pad layer 316 between the bonding pad layer 316 and the substrate 300 .",
"The substrate 300 can be a semiconductor substrate or a substrate with multi-layered interconnects therein.",
"[0037] The current conduction structure 314 and the mechanical support structure 312 are two detached structures connected only by the bonding layer 316 .",
"Furthermore, an insulation layer 306 is formed between the current conduction structure 314 and the mechanical support structure 312 .",
"The insulation layer 306 comprises more than one insulating material layer and the insulating material is silicon nitride, silicon oxide or silicon oxynitride.",
"[0038] The current conduction structure 314 includes a plurality of serially connected metallic layers 304 a , 304 b and 304 c , each located at a different height level between the bonding pad layer 316 and the substrate 300 .",
"The conductive metallic layers 304 a , 304 b , 304 c are linked together via plugs 310 b and 310 c , respectively.",
"The conductive metallic layer 304 c and the bonding pad layer 316 are linked together via plugs 310 d .",
"The conductive metallic layer 304 a and the substrate 300 are linked together via plugs 310 a to form a current conduction structure 314 between the bonding pad layer 316 and the substrate 300 .",
"The conductive metallic layers 304 a , 304 b , 304 c connect electrically with a signal line (not shown).",
"Hence, the conductive metallic layers are electrically connected to a device section (not shown) on substrate 300 .",
"The conductive metallic layers 304 a , 304 b and 304 c can be local metallic interconnects, for example.",
"[0039] The mechanical support structure 312 includes a plurality of serially connected support metallic layers 302 a , 302 b and 302 c , each located at a different height level between the bonding pad layer 316 and the substrate 300 .",
"The support metallic layers 302 a , 302 b , 302 c are linked together via plugs 308 b and 308 c .",
"The support metallic layer 302 c and the bonding pad layer 316 are linked together via plugs 308 d .",
"The support metallic layer 302 a and the substrate 300 are linked together via plugs 308 a to form a mechanical support structure 314 between the bonding pad layer 316 and the substrate 300 .",
"The support metallic layers can be a local metallic interconnects, for example.",
"[0040] Since the plugs 310 a of the current conduction structure 314 and the plugs 308 a of the mechanical support structure 312 are formed on the substrate 300 , stress on the bonding pad layer 316 is transmitted to the plugs 310 a and the plugs 308 a via the current conduction structure 314 and the mechanical support structure 312 , respectively.",
"Finally, the stress is transmitted to the substrate 300 via the plugs 310 a and 308 a so that stress is evenly distributed across the entire substrate 100 .",
"[0041] Because cross-sectional area of the conductive metallic layers 304 a , 304 b , 304 c in the current conduction structure 314 is smaller than a conventional bonding pad metallic layer, the number of plugs 310 b , 310 c , 310 d attached to various conductive metallic layers 304 a , 304 b , 304 c is smaller than the number of plugs attached to a conventional bonding pad metallic layer.",
"Hence, overall in-processing current delivered to the device section of the substrate 300 via the current conduction structure 314 is greatly reduced.",
"Ultimately, product yield is increased and production cost is lowered.",
"[0042] Besides the capacity to conduct current between the bonding pad layer 316 and the substrate 300 , the current conduction structure 314 also has some mechanical support capacity.",
"Through a special patterning of the plugs 310 a , 310 b , 310 c and 310 d , the current conduction structure 314 can increase plug density of the mechanical support structure 312 so that bonding pad 316 has the capacity to support a greater load.",
"In addition, the current conduction structure 314 and the mechanical support structure 312 are detached structures.",
"Hence, an increase in plug density for the mechanical support structure 312 will not lead to an increase in current transmitted to the device section during plasma processing.",
"[0043] Furthermore, cross-sectional profile of the bonding pad 316 , the conductive metallic layers 304 a , 304 b , 304 c and the support metallic layers 302 a , 302 b , 302 c can have any shape according to actual processing requirements.",
"Similarly, cross-sectional profiles of various plugs including 308 a , 308 b , 308 c , 308 d , 310 a , 310 b , 310 c and 310 d can have any shape.",
"Moreover, the plugs can be arranged in whatever pattern is suitable for a particular application.",
"[0044] In the second embodiment, although a current conduction structure with three conductive metallic layers and a mechanical support structure with three support metallic layer are shown, there is no limitation to the total number of layers used.",
"In general, a current conduction structure can have a multiple of conductive metallic layers and a mechanical support structure can have a multiple of support metallic layers between the bonding pad layer and the substrate.",
"[0045] FIGS. 4 is a sketch showing a bonding pad structure fabricated according to a third preferred embodiment of this invention.",
"In the first embodiment, the number of conductive metallic layers and the number of support metallic layers are identical.",
"In the third embodiment, however, the number of conductive metallic layers is different from the number of support metallic layers.",
"The following is a detailed description of the second embodiment of this invention.",
"[0046] As shown in FIG. 4, the bonding structure includes a substrate 400 , a mechanical support structure 412 , a current conduction structure 414 and a bonding pad layer 416 .",
"The bonding pad layer 416 is above the substrate 400 .",
"The current conduction structure 414 is attached to the bonding pad layer 416 between the bonding pad layer 416 and the substrate 400 .",
"Similarly, the mechanical support structure 412 is also attached to the bonding pad layer 416 between the bonding pad layer 416 and the substrate 400 .",
"The substrate 400 can be a semiconductor substrate or a substrate with multi-layered interconnects therein.",
"[0047] The current conduction structure 414 and the mechanical support structure 412 are two detached structures connected only by the bonding layer 416 .",
"Furthermore, an insulation layer 406 is formed between the current conduction structure 414 and the mechanical support structure 412 .",
"The insulation layer 406 comprises of more than one insulating material layer and the insulating material is silicon nitride, silicon oxide or silicon oxynitride.",
"[0048] The current conduction structure 414 includes a plurality of serially connected metallic layers 404 a and 404 b , each located at a different height level between the bonding pad layer 416 and the substrate 400 .",
"The conductive metallic layers 404 a , 404 b are linked together via plugs 410 a .",
"The conductive metallic layer 404 b and the bonding pad layer 416 are linked together via plugs 410 b .",
"The conductive metallic layer 404 a is in contact with the substrate 400 so that the current conduction structure 414 actually connects the bonding pad layer 416 and the substrate 400 together.",
"The conductive metallic layers 404 a , 404 b connect electrically with a signal line (not shown).",
"Hence, the conductive metallic layers are electrically connected to a device section (not shown) on substrate 400 .",
"The conductive metallic layers can be local metallic interconnects, for example.",
"[0049] The mechanical support structure 412 includes a plurality of serially connected support metallic layers 402 a , 402 b , 402 c each located at a different height level between the bonding pad layer 416 and the substrate 400 .",
"The support metallic layers 402 a , 402 b , 402 c are linked together via plugs 408 a and 408 b .",
"The support metallic layer 402 c and the bonding pad layer 416 are linked together via plugs 408 c .",
"The support metallic layer 402 a and the substrate 400 are in contact with each other to form the mechanical support structure 412 between the bonding pad layer 416 and the substrate 400 .",
"The support metallic layers can be local metallic interconnects, for example.",
"[0050] Since the bottom conductive metallic layer 404 a of the current conduction structure 414 and the bottom support metallic layer 402 a of the mechanical support structure 412 are formed on the substrate 400 , stress on the bonding pad layer 416 is transmitted to the conductive metallic layer 404 a and the support metallic layer 402 a via the current conduction structure 414 and the mechanical support structure 412 , respectively.",
"The stress is transmitted to the substrate 400 via the conductive metallic layer 404 a and the support metallic layer 402 a .",
"Ultimately, stress is evenly distributed across the entire substrate 400 .",
"[0051] When the cross-sectional area of the conductive metallic layers in the current conduction structure 414 is much smaller than the cross-sectional area of the support metallic layers in the mechanical support structure 412 , the number of conductive metallic layer in the current conduction structure 414 cannot be identical to the number of support metallic layer in the mechanical support structure 412 .",
"This is because the purpose of the current conduction structure 414 is to provide an electrical path between the bonding pad layer and the substrate devices.",
"The stress supporting capacity of the current conduction structure 414 is of secondary importance.",
"The effect of having a number of conductive metallic layers in the current conduction structure that differs from the number of support metallic layer is relatively small.",
"[0052] Furthermore, cross-sectional profile of the bonding pad 416 , the conductive metallic layers 404 a , 404 b and the support metallic layers 402 a , 402 b , 402 c can have any shape according to actual processing requirements.",
"Similarly, cross-sectional profile of various plugs including 408 a , 408 b , 408 c , 410 a , and 410 b can have any shape.",
"Moreover, the plugs can be arranged in whatever pattern suitable for a particular application.",
"[0053] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention.",
"In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents."
] |
CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation application of U.S. patent application Ser. No. 10/711,140 filed Aug. 27, 2004.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a varactor, and more particularly, to a method for fabricating a PN-junction varactor having improved quality factor (Q factor).
2. Description of the Prior Art
A varactor is, essentially, a variable voltage capacitor. The capacitance of a varactor, when within its operating parameters, decreases as a voltage applied to the device increases. Such a device is useful in the design and construction of oscillator circuits now commonly used for, among other things, communications devices. Varactors are typically employed in voltage-controlled oscillators (VCOs) where a frequency of an oscillator is controlled by an applied current or voltage. In such instances, the VCOs are used when a variable frequency is required, or when a signal needs to be synchronized to a reference signal.
Numerous varactors have been developed and are employed in integrated circuit technologies, for example, PN-diodes, Schottky diodes or MOS-diodes as a varactor in bipolar, CMOS and BiCMOS technologies. Among these, two varactor structures are most frequently used: the PN-junction varactor and the MOS varactor. Currently the PN-junction varactor is predominantly used in LC oscillators. Both these structures can be implemented using standard CMOS processes.
Referring to FIG. 1 , a prior art PN diode varactor is illustrated in a cross-sectional view. As shown in FIG. 1 , a substrate 10 includes an N-well 12 , and a plurality of isolation structures 14 , such as field oxide layer or shallow trench isolation (STI), on surfaces of the N-well 12 and the substrate 10 . The isolation structures 14 define a plurality of predetermined regions on the N-well 12 to form at least an N-type doping region 16 and a P-type doping region 18 , thus completing a diode structure having a PN junction. When the diode is reverse-biased, a depletion region occurs in the PN junction of the diode and acts as a dielectric, so that the N-type doping region 16 and the P-type doping region 18 separated by the dielectric form an equivalent capacitor. With an adjustment in the voltage across the anode (the P-type doping region 18 ) and the cathode (the N-type doping region 16 ) of the diode, a width of the depletion region varies to change the equivalent capacitance of the varactor.
Referring to FIG. 2 , a prior art MOS varactor is illustrated in a cross-sectional view. The prior art MOS varactor is formed on an N-well 22 . The prior art MOS varactor includes a polysilicon gate structure 26 serving as an anode of the MOS varactor, a gate oxide layer 28 between the gate structure 26 and the N-well 22 , and two N + doped regions 24 on both sides of the gate structure 26 , wherein the N + doped regions 24 , which are implanted in the N-well 22 , serve as a cathode of the MOS varactor. N type lightly doped drain regions 25 are also provided.
The main drawback of the prior art PN junction varactor as set forth in FIG. 1 is a low maximum to minimum capacitance ratio and small quality factor (Q factor). The MOS varactor does not suffer on this account, with a high maximum to minimum capacitance ratio of roughly four to one for a typical 0.25 μm CMOS process. Furthermore, the MOS varactor's ratio increases in deep submicron processes due to the thinner gate oxide used. However, the MOS varactor's transition from maximum to minimum capacitance is abrupt. This gives a MOS varactor a small, highly non-linear voltage control range.
SUMMARY OF THE INVENTION
It is therefore a primary object of the claimed invention to provide a varactor to improve the electrical performance thereof.
It is another object of the claimed invention to provide a CMOS-compatible method for fabricating a junction varactor having improved quality factor.
According to the claimed invention, a method for fabricating a junction varactor is disclosed. The method includes: providing a substrate having thereon an ion well of first conductivity type; forming first and second gate fingers across the ion well, wherein the first and second gate fingers are substantially parallel to one another; forming a central lightly doped region of a second conductivity type in the ion well between the first and second gate fingers; forming sideward lightly doped regions of the first conductivity type in the ion well at sides of the first or second gate finger opposite to the central lightly doped region; forming spacers on sidewalls of the first and second gate fingers; implanting a central heavily doped region of the second conductivity type into the ion well between the first and second gate fingers; and implanting, in a self-aligned fashion, sideward heavily doped regions of the first conductivity type into the sideward lightly doped regions.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:
FIG. 1 is a cross-sectional schematic diagram illustrating a prior art PN junction varactor;
FIG. 2 is a cross-sectional schematic diagram illustrating a prior art MOS varactor;
FIG. 3 is a schematic top view showing the layout of a junction varactor in accordance with one preferred embodiment of the present invention;
FIG. 4 is a schematic cross-sectional diagram showing the junction varactor along line AA of FIG. 3 ; and
FIGS. 5-8 are schematic cross-sectional diagrams showing the process steps for making the junction varactor as set forth in FIG. 4 according to this invention; and
FIG. 9 is a schematic cross-sectional diagram showing a junction varactor according to another preferred embodiment of this invention.
DETAILED DESCRIPTION
The present invention, which provides novel junction varactors for CMOS and BiCMOS technologies as well as a method for fabricating the same, will now be described in more detail by referring to the drawings that accompany the present application. It is to be understood that the conductivity types, device or circuit layout, or materials used as set forth in the following detailed description and figures are only for illustration purpose. The scope of this invention should be construed as limited only by the metes and bounds of the appended claims.
Referring initially to FIG. 3 and FIG. 4 , wherein FIG. 3 is a schematic top view showing the basic layout of a junction varactor 80 in accordance with one preferred embodiment of the present invention; FIG. 4 is a schematic cross-sectional diagram showing the junction varactor 80 along line AA of FIG. 3 . According to the preferred embodiment of the present invention, the junction varactor 80 is formed on an N-well 100 , which may be formed on a commercially available P type silicon substrate or a silicon-on-insulator (SOI) substrate. The N-well 100 is electrically isolated by shallow trench isolation (STI) 200 . In a case that the substrate is an SOI substrate, the STI 200 reaches down to a buried oxide layer and thus renders the N-well 100 in a floating status.
The junction varactor 80 further comprises an elongated gate finger 101 lying across the N-well 100 , and a gate finger 102 situated at one side of the gate finger 101 . As specifically indicated in FIG. 3 , the gate finger 102 , which overlies the N-well 100 , is arranged substantially in parallel with the gate finger 101 . Both of the gate finger 101 and gate finger 102 have vertical sidewalls, on which spacers 101 a and 102 a are formed. The gate finger 101 and gate finger 102 may be formed of polysilicon or metals. A gate dielectric layer 101 b and a gate dielectric layer 102 b are provided under the gate fingers 101 and 102 , respectively. A P + doping region 112 , which serves as an anode of the junction varactor 80 , is formed in the N-well 100 between the gate fingers 101 and 102 . Preferably, the P + doping region 112 is contiguous with P-type lightly doped drains (PLDD) 113 that extend laterally to under the spacers 101 a and 102 a.
As best seen in FIG. 4 , in the N-well 100 , at one side of the gate finger 101 that is opposite to the P + doping region 112 , an N+ doping region 114 is provided. An N-type lightly doped drain (NLDD) 121 that is merged with the N + doping region 114 extends laterally to the gate 101 . In the N-well 100 , at one side of the gate finger 102 that is opposite to the P + doping region 112 , an N + doping region 116 is provided. Likewise, an NLDD 122 that is merged with the N + doping region 116 extends laterally to the gate 102 . The N + doping region 114 is electrically coupled to the N + doping region 116 by interconnection, and together serves as a cathode of the junction varactor 80 . Furthermore, to reduce sheet resistance of the varactor 80 , a salicide layer 103 is optionally provided on the exposed surface of the P + doping region 112 , the N + doping region 114 , and the N + doping region 116 .
Compared with the prior art junction varactors, the present invention junction varactor has a lower resistance because there is no STI formed between the anode and cathode of the varactor. Therefore, the present invention junction varactor has a higher Q factor and better performance. In operation, the gate fingers 101 and 102 are preferably biased to a pre-selected voltage V G . In the case as demonstrated in FIG. 3 and FIG. 4 , the pre-selected voltage V G is a positive voltage such as V CC . The positive voltage provided to gate fingers 101 and 102 results in accumulated electrons in the channel regions that are located under the gate fingers 101 and 102 , thereby further reducing resistance of the varactor 80 . By altering the bias between the anode and cathode of the junction varactor 80 , the capacitance of the junction varactor may be tuned in an extended tuning range.
Reference is now made to the embodiment illustrated in FIGS. 5-8 wherein the various processing steps employed in fabricating the inventive junction varactor are shown. The method for fabricating the inventive junction varactor in accordance with the preferred embodiment of this invention is CMOS compatible. FIG. 5 illustrates the first step used in forming the inventive junction varactor. As shown in FIG. 5 , a substrate (not explicitly shown) is provided, on which an N-well 100 is formed by any method known in the art, for example, ion implantation. The N-well 100 is isolated by STI (not shown). Subsequently, an insulation layer (not explicitly shown) such as thermally grown gate oxide layer is formed on the surface of the N-well 100 . A layer of polysilicon is deposited over the insulation layer, and then patterned to form gate structures 101 and 102 using conventional lithographic and dry etching processes. The deposition of the polysilicon layer may be fulfilled by conventional LPCVD. In another case, the gates may be made of metals.
As shown in FIG. 6 , using a suitable mask or an “NLDD implant photo” to mask the area between the gate 101 and the gate 102 , an NLDD ion implantation process is carried out to dope ions such as arsenic into the N-well 100 at one side of the gate 101 and at one side of the gate 102 , thereby forming an NLDD region 121 and NLDD region 122 .
As shown in FIG. 7 , using a suitable mask or a so-called “PLDD implant photo” to open the area between the gate 101 and the gate 102 , a PLDD ion implantation process is carried out to dope ions such as boron into the N-well 100 in the area between the gate 101 and the gate 102 , thereby forming a PLDD region 113 .
As shown in FIG. 8 , using methods known in the art, spacers 101 a and 102 a are formed on sidewalls of the gates 101 and 102 , respectively. Subsequently, using a suitable mask or so-called “N + implant photo” to mask the area between the gate 101 and the gate 102 , an N + ion implantation process is carried out to dope a high dosage of ions such as arsenic into the N-well 100 at one side of the gate 101 and at one side of the gate 102 , thereby forming N + region 114 and N + region 116 . Finally, using the PLDD implant photo to expose the area between the gate 101 and the gate 102 , a P + ion implantation is carried to form the P + doping region 112 . After implementing a conventional self-aligned silicidation process, the junction varactor 80 as set forth in FIG. 4 is produced.
FIG. 9 depicts a schematic cross-sectional view of junction varactor 800 according to another preferred embodiment of this invention. As shown in FIG. 9 , the junction varactor 800 is formed on a P-well 200 . The junction varactor 800 comprises an elongated gate finger 201 lying across the P-well 200 , and a gate finger 202 situated at one side of the gate finger 201 . The gate finger 202 , which overlies the P-well 200 , is arranged substantially in parallel with the gate finger 201 . Both of the gate finger 201 and gate finger 202 have vertical sidewalls, on which spacers 201 a and 202 a are formed. The gate finger 201 and gate finger 202 may be formed of polysilicon or metals. A gate dielectric layer 201 b and a gate dielectric layer 202 b are provided under the gate fingers 201 and 202 , respectively. An N + doping region 212 , which serves as an anode of the junction varactor 800 , is formed in the P-well 200 between the gate fingers 201 and 202 . Preferably, the N + doping region 212 is contiguous with N-type lightly doped drains (NLDD) 213 that extend laterally to under the spacers 201 a and 202 a.
In the P-well 100 , at one side of the gate finger 201 that is opposite to the N + doping region 212 , a P + doping region 214 is provided. A P-type lightly doped drain (PLDD) 221 that is merged with the P + doping region 214 extends laterally to the gate 201 . At one side of the gate finger 202 that is opposite to the P + doping region 212 , a N + doping region 216 is provided in the P-well 200 . Likewise, a PLDD 222 that is merged with the P + doping region 216 extends laterally to the gate 202 . The P + doping region 214 is electrically coupled to the P + doping region 216 by interconnection, and together serves as a cathode of the junction varactor 800 . Likewise, to reduce sheet resistance of the varactor 800 , a salicide layer 203 is optionally provided on the exposed surface of the N + doping region 212 , the P + doping region 214 , and the P + doping region 216 . In operation, the gate fingers 201 and 202 are preferably biased to a pre-selected voltage V G . By way of example, in the case as demonstrated in FIG. 9 , the pre-selected voltage V G is V SS . By altering the bias between the anode and cathode of the junction varactor 800 , the capacitance of the junction varactor may be tuned in an extended tuning range.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims. | A junction varactor includes a gate finger lying across an ion well of a semiconductor substrate; a gate dielectric situated between the gate finger and the ion well; a first ion diffusion region with first conductivity type located in the ion well at one side of the gate finger, the first ion diffusion region serving as an anode of the junction varactor; and a second ion diffusion region with a second conductivity type located in the ion well at the other side of the gate finger, the second ion diffusion region serving as a cathode of the junction varactor. In operation, the gate of the junction varactor is biased to a gate voltage V G that is not equal to 0 volt. | Identify the most important claim in the given context and summarize it | [
"CROSS REFERENCE TO RELATED APPLICATIONS This is a continuation application of U.S. patent application Ser.",
"No. 10/711,140 filed Aug. 27, 2004.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present invention relates generally to a varactor, and more particularly, to a method for fabricating a PN-junction varactor having improved quality factor (Q factor).",
"Description of the Prior Art A varactor is, essentially, a variable voltage capacitor.",
"The capacitance of a varactor, when within its operating parameters, decreases as a voltage applied to the device increases.",
"Such a device is useful in the design and construction of oscillator circuits now commonly used for, among other things, communications devices.",
"Varactors are typically employed in voltage-controlled oscillators (VCOs) where a frequency of an oscillator is controlled by an applied current or voltage.",
"In such instances, the VCOs are used when a variable frequency is required, or when a signal needs to be synchronized to a reference signal.",
"Numerous varactors have been developed and are employed in integrated circuit technologies, for example, PN-diodes, Schottky diodes or MOS-diodes as a varactor in bipolar, CMOS and BiCMOS technologies.",
"Among these, two varactor structures are most frequently used: the PN-junction varactor and the MOS varactor.",
"Currently the PN-junction varactor is predominantly used in LC oscillators.",
"Both these structures can be implemented using standard CMOS processes.",
"Referring to FIG. 1 , a prior art PN diode varactor is illustrated in a cross-sectional view.",
"As shown in FIG. 1 , a substrate 10 includes an N-well 12 , and a plurality of isolation structures 14 , such as field oxide layer or shallow trench isolation (STI), on surfaces of the N-well 12 and the substrate 10 .",
"The isolation structures 14 define a plurality of predetermined regions on the N-well 12 to form at least an N-type doping region 16 and a P-type doping region 18 , thus completing a diode structure having a PN junction.",
"When the diode is reverse-biased, a depletion region occurs in the PN junction of the diode and acts as a dielectric, so that the N-type doping region 16 and the P-type doping region 18 separated by the dielectric form an equivalent capacitor.",
"With an adjustment in the voltage across the anode (the P-type doping region 18 ) and the cathode (the N-type doping region 16 ) of the diode, a width of the depletion region varies to change the equivalent capacitance of the varactor.",
"Referring to FIG. 2 , a prior art MOS varactor is illustrated in a cross-sectional view.",
"The prior art MOS varactor is formed on an N-well 22 .",
"The prior art MOS varactor includes a polysilicon gate structure 26 serving as an anode of the MOS varactor, a gate oxide layer 28 between the gate structure 26 and the N-well 22 , and two N + doped regions 24 on both sides of the gate structure 26 , wherein the N + doped regions 24 , which are implanted in the N-well 22 , serve as a cathode of the MOS varactor.",
"N type lightly doped drain regions 25 are also provided.",
"The main drawback of the prior art PN junction varactor as set forth in FIG. 1 is a low maximum to minimum capacitance ratio and small quality factor (Q factor).",
"The MOS varactor does not suffer on this account, with a high maximum to minimum capacitance ratio of roughly four to one for a typical 0.25 μm CMOS process.",
"Furthermore, the MOS varactor's ratio increases in deep submicron processes due to the thinner gate oxide used.",
"However, the MOS varactor's transition from maximum to minimum capacitance is abrupt.",
"This gives a MOS varactor a small, highly non-linear voltage control range.",
"SUMMARY OF THE INVENTION It is therefore a primary object of the claimed invention to provide a varactor to improve the electrical performance thereof.",
"It is another object of the claimed invention to provide a CMOS-compatible method for fabricating a junction varactor having improved quality factor.",
"According to the claimed invention, a method for fabricating a junction varactor is disclosed.",
"The method includes: providing a substrate having thereon an ion well of first conductivity type;",
"forming first and second gate fingers across the ion well, wherein the first and second gate fingers are substantially parallel to one another;",
"forming a central lightly doped region of a second conductivity type in the ion well between the first and second gate fingers;",
"forming sideward lightly doped regions of the first conductivity type in the ion well at sides of the first or second gate finger opposite to the central lightly doped region;",
"forming spacers on sidewalls of the first and second gate fingers;",
"implanting a central heavily doped region of the second conductivity type into the ion well between the first and second gate fingers;",
"and implanting, in a self-aligned fashion, sideward heavily doped regions of the first conductivity type into the sideward lightly doped regions.",
"These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.",
"BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification.",
"The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.",
"In the drawings: FIG. 1 is a cross-sectional schematic diagram illustrating a prior art PN junction varactor;",
"FIG. 2 is a cross-sectional schematic diagram illustrating a prior art MOS varactor;",
"FIG. 3 is a schematic top view showing the layout of a junction varactor in accordance with one preferred embodiment of the present invention;",
"FIG. 4 is a schematic cross-sectional diagram showing the junction varactor along line AA of FIG. 3 ;",
"and FIGS. 5-8 are schematic cross-sectional diagrams showing the process steps for making the junction varactor as set forth in FIG. 4 according to this invention;",
"and FIG. 9 is a schematic cross-sectional diagram showing a junction varactor according to another preferred embodiment of this invention.",
"DETAILED DESCRIPTION The present invention, which provides novel junction varactors for CMOS and BiCMOS technologies as well as a method for fabricating the same, will now be described in more detail by referring to the drawings that accompany the present application.",
"It is to be understood that the conductivity types, device or circuit layout, or materials used as set forth in the following detailed description and figures are only for illustration purpose.",
"The scope of this invention should be construed as limited only by the metes and bounds of the appended claims.",
"Referring initially to FIG. 3 and FIG. 4 , wherein FIG. 3 is a schematic top view showing the basic layout of a junction varactor 80 in accordance with one preferred embodiment of the present invention;",
"FIG. 4 is a schematic cross-sectional diagram showing the junction varactor 80 along line AA of FIG. 3 .",
"According to the preferred embodiment of the present invention, the junction varactor 80 is formed on an N-well 100 , which may be formed on a commercially available P type silicon substrate or a silicon-on-insulator (SOI) substrate.",
"The N-well 100 is electrically isolated by shallow trench isolation (STI) 200 .",
"In a case that the substrate is an SOI substrate, the STI 200 reaches down to a buried oxide layer and thus renders the N-well 100 in a floating status.",
"The junction varactor 80 further comprises an elongated gate finger 101 lying across the N-well 100 , and a gate finger 102 situated at one side of the gate finger 101 .",
"As specifically indicated in FIG. 3 , the gate finger 102 , which overlies the N-well 100 , is arranged substantially in parallel with the gate finger 101 .",
"Both of the gate finger 101 and gate finger 102 have vertical sidewalls, on which spacers 101 a and 102 a are formed.",
"The gate finger 101 and gate finger 102 may be formed of polysilicon or metals.",
"A gate dielectric layer 101 b and a gate dielectric layer 102 b are provided under the gate fingers 101 and 102 , respectively.",
"A P + doping region 112 , which serves as an anode of the junction varactor 80 , is formed in the N-well 100 between the gate fingers 101 and 102 .",
"Preferably, the P + doping region 112 is contiguous with P-type lightly doped drains (PLDD) 113 that extend laterally to under the spacers 101 a and 102 a. As best seen in FIG. 4 , in the N-well 100 , at one side of the gate finger 101 that is opposite to the P + doping region 112 , an N+ doping region 114 is provided.",
"An N-type lightly doped drain (NLDD) 121 that is merged with the N + doping region 114 extends laterally to the gate 101 .",
"In the N-well 100 , at one side of the gate finger 102 that is opposite to the P + doping region 112 , an N + doping region 116 is provided.",
"Likewise, an NLDD 122 that is merged with the N + doping region 116 extends laterally to the gate 102 .",
"The N + doping region 114 is electrically coupled to the N + doping region 116 by interconnection, and together serves as a cathode of the junction varactor 80 .",
"Furthermore, to reduce sheet resistance of the varactor 80 , a salicide layer 103 is optionally provided on the exposed surface of the P + doping region 112 , the N + doping region 114 , and the N + doping region 116 .",
"Compared with the prior art junction varactors, the present invention junction varactor has a lower resistance because there is no STI formed between the anode and cathode of the varactor.",
"Therefore, the present invention junction varactor has a higher Q factor and better performance.",
"In operation, the gate fingers 101 and 102 are preferably biased to a pre-selected voltage V G .",
"In the case as demonstrated in FIG. 3 and FIG. 4 , the pre-selected voltage V G is a positive voltage such as V CC .",
"The positive voltage provided to gate fingers 101 and 102 results in accumulated electrons in the channel regions that are located under the gate fingers 101 and 102 , thereby further reducing resistance of the varactor 80 .",
"By altering the bias between the anode and cathode of the junction varactor 80 , the capacitance of the junction varactor may be tuned in an extended tuning range.",
"Reference is now made to the embodiment illustrated in FIGS. 5-8 wherein the various processing steps employed in fabricating the inventive junction varactor are shown.",
"The method for fabricating the inventive junction varactor in accordance with the preferred embodiment of this invention is CMOS compatible.",
"FIG. 5 illustrates the first step used in forming the inventive junction varactor.",
"As shown in FIG. 5 , a substrate (not explicitly shown) is provided, on which an N-well 100 is formed by any method known in the art, for example, ion implantation.",
"The N-well 100 is isolated by STI (not shown).",
"Subsequently, an insulation layer (not explicitly shown) such as thermally grown gate oxide layer is formed on the surface of the N-well 100 .",
"A layer of polysilicon is deposited over the insulation layer, and then patterned to form gate structures 101 and 102 using conventional lithographic and dry etching processes.",
"The deposition of the polysilicon layer may be fulfilled by conventional LPCVD.",
"In another case, the gates may be made of metals.",
"As shown in FIG. 6 , using a suitable mask or an “NLDD implant photo”",
"to mask the area between the gate 101 and the gate 102 , an NLDD ion implantation process is carried out to dope ions such as arsenic into the N-well 100 at one side of the gate 101 and at one side of the gate 102 , thereby forming an NLDD region 121 and NLDD region 122 .",
"As shown in FIG. 7 , using a suitable mask or a so-called “PLDD implant photo”",
"to open the area between the gate 101 and the gate 102 , a PLDD ion implantation process is carried out to dope ions such as boron into the N-well 100 in the area between the gate 101 and the gate 102 , thereby forming a PLDD region 113 .",
"As shown in FIG. 8 , using methods known in the art, spacers 101 a and 102 a are formed on sidewalls of the gates 101 and 102 , respectively.",
"Subsequently, using a suitable mask or so-called “N + implant photo”",
"to mask the area between the gate 101 and the gate 102 , an N + ion implantation process is carried out to dope a high dosage of ions such as arsenic into the N-well 100 at one side of the gate 101 and at one side of the gate 102 , thereby forming N + region 114 and N + region 116 .",
"Finally, using the PLDD implant photo to expose the area between the gate 101 and the gate 102 , a P + ion implantation is carried to form the P + doping region 112 .",
"After implementing a conventional self-aligned silicidation process, the junction varactor 80 as set forth in FIG. 4 is produced.",
"FIG. 9 depicts a schematic cross-sectional view of junction varactor 800 according to another preferred embodiment of this invention.",
"As shown in FIG. 9 , the junction varactor 800 is formed on a P-well 200 .",
"The junction varactor 800 comprises an elongated gate finger 201 lying across the P-well 200 , and a gate finger 202 situated at one side of the gate finger 201 .",
"The gate finger 202 , which overlies the P-well 200 , is arranged substantially in parallel with the gate finger 201 .",
"Both of the gate finger 201 and gate finger 202 have vertical sidewalls, on which spacers 201 a and 202 a are formed.",
"The gate finger 201 and gate finger 202 may be formed of polysilicon or metals.",
"A gate dielectric layer 201 b and a gate dielectric layer 202 b are provided under the gate fingers 201 and 202 , respectively.",
"An N + doping region 212 , which serves as an anode of the junction varactor 800 , is formed in the P-well 200 between the gate fingers 201 and 202 .",
"Preferably, the N + doping region 212 is contiguous with N-type lightly doped drains (NLDD) 213 that extend laterally to under the spacers 201 a and 202 a. In the P-well 100 , at one side of the gate finger 201 that is opposite to the N + doping region 212 , a P + doping region 214 is provided.",
"A P-type lightly doped drain (PLDD) 221 that is merged with the P + doping region 214 extends laterally to the gate 201 .",
"At one side of the gate finger 202 that is opposite to the P + doping region 212 , a N + doping region 216 is provided in the P-well 200 .",
"Likewise, a PLDD 222 that is merged with the P + doping region 216 extends laterally to the gate 202 .",
"The P + doping region 214 is electrically coupled to the P + doping region 216 by interconnection, and together serves as a cathode of the junction varactor 800 .",
"Likewise, to reduce sheet resistance of the varactor 800 , a salicide layer 203 is optionally provided on the exposed surface of the N + doping region 212 , the P + doping region 214 , and the P + doping region 216 .",
"In operation, the gate fingers 201 and 202 are preferably biased to a pre-selected voltage V G .",
"By way of example, in the case as demonstrated in FIG. 9 , the pre-selected voltage V G is V SS .",
"By altering the bias between the anode and cathode of the junction varactor 800 , the capacitance of the junction varactor may be tuned in an extended tuning range.",
"Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.",
"Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims."
] |
This application is the National Stage of International Application Ser. No. PCT/AU2005/000244 filed on Feb. 25, 2005; and this application claims priority of application Ser. No. 2004900942 filed in Australia on Feb. 26, 2004 under 35 U.S.C. § 119; the entire contents of all are hereby incorporated by reference.
This invention relates to improvements in Surface Acoustic Wave [SAW] devices and particularly layered SAW devices used as sensors.
BACKGROUND OF THE INVENTION
SAW devices are usually used in a closed loop with an amplifier to make an oscillator. There are patents which describes setting up a stable oscillator using a SAW device to generate clock pulses for electronic circuits. U.S. Pat. No. 3,979,697 discloses an oscillator in which the “tank circuit” or feedback element is a surface acoustic wave (SAW) bandpass filter (delay line). U.S. Pat. No. 4,868,524 discloses an RF circuit to generate a stable carrier signal using a Voltage Controlled Saw Oscillator. U.S. Pat. No. 5,126,694 discloses A SAW stabilized oscillator includes a phase locking circuit which is phase locked to a lower frequency reference signal having an odd order difference with respect to the fundamental frequency of the SAW oscillator.
SAW devices have been used as sensors in liquid and gaseous environments. U.S. Pat. No. 4,562,371 discloses a SAW device comprising a ZnO piezo layer on a cut crystalline silicon substrate that propagates Rayleigh waves.
The surface acoustic waves polarizes in 3 directions and can be classified as longitudinal wave motion, Normal waves or shear horizontal waves. A class of shear horizontal [SH] waves are called Love waves which are propagated in layered devices that concentrate the wave energy in a highly confined region near to the surface.
Rayleigh wave sensors have been useful in gaseous environments but they are not suitable for liquid environments because the surface-normal displacement causes strong radiative loss into the liquid. For sensing in liquids shear horizontal [SH] polarised wave modes are preferred since the particle displacement is parallel to the device surface and normal to the direction of propagation. This allows a wave to propagate in contact with a liquid without coupling excessive acoustic energy into the liquid. However the SH wave is distributed through the substrate and therefore does not have the same sensitivity as the SAW. For increased sensitivity Love waves which are SH-polarised guided surface waves may be used. The waves propagate in a layered structure consisting of a piezoelectric substrate and a guiding layer which couples the elastic waves generated in the substrate to the near surface. They are extremely sensitive to surface perturbations due to the energy confinement to the near surface. By observing the magnitude of perturbations it is possible to measure the strength of the interaction. The interactions may be caused by mass density, elastic stiffness, liquid viscosity, electric and dielectric properties. The more sensitive is the device the smaller the quantities that can be measured.
U.S. Pat. Nos. 5,130,257, 5,216,312, 5,283,037 and 5,321,331 disclose love mode SAW sensors used in liquid environments. The love waves are produced by cutting the piezo electric material such as lithium niobate, lithium tantalate or quartz to couple energy from the interdigital transducers [IDT's] of the SAW device into shear transverse or love waves that enable the wave energy to be trapped at the substrate surface.
U.S. Pat. No. 5,705,399 discloses a SAW sensor for liquid environments having an AT cut quartz piezo substrate with electrodes connected to a first side in contact with a liquid and a second side that is not in contact. The sensor may be used to detect biological species such as antigens.
WO02/095940 discloses a love mode SAW sensor using a piezo layer of ZnO on a piezo electric quartz crystal.
To improve the sensitivity of sensors the stability of the frequency of the device needs to be addressed. U.S. Pat. No. 6,122,954 discloses a SAW sensor with a resonant frequency range of 200 to 2000 MHz and a temperature control system. It is an object of this invention to improve the reliability of SAW sensors and to optimise the operational performance of the sensors.
BRIEF DESCRIPTION OF THE INVENTION
To this end the present invention provides a surface acoustic wave sensor which incorporates
a) a first layered SAW device consisting of a piezoelectric crystal with interdigital electrodes on its surface, and second piezoelectric layer over said interdigital electrodes b) a second layered SAW device consisting of a piezoelectric crystal with interdigital electrodes on its surface, a second piezoelectric layer over said interdigital electrodes and an analyte sensitive surface on said second piezoelectric layer c) both SAW devices are fabricated on the same substrate d) reflectors are located adjacent the interdigital electrodes in each saw device to reduce the bandwidth of the device e) the resonator circuits of each saw sensor incorporate amplifiers which are dependent.
When the SAW device interacts with a target analytes the operating frequency changes. The change of operating frequency is proportional to the magnitude of the target analyte in the environment. The oscillation system needs to have a high Q and a stable frequency response.
By using the first layered SAW device as a reference sensor and fabricating them on the same substrate the effect of environmental noise can be reduced. By using reflectors to reduce the bandwidth the Q of the devices is increased.
Preferably the piezoelectric substrate is cut for propagation of Love mode waves and may be quartz crystal, lithium Niobate [LiNbO 3 ], lithium tantalate [LiTaO 3 ], langasite or langatite.
Preferably the second layer is a piezoelectric film such as layer is zinc oxide, AlN LiTaO3, LiTaO3 or quartz
The second layer can be a non-piezoelectric which has a capability to confine the acoustic energy with itself such as silicon nitride, different types of metal oxides, polymers or metal compounds.
A preferred piezo substrate is 90° rotated ST-cut quartz crystal which has a propagation speed of 5000 m/s and the dominant wave is SSBW (Surface Skimming Bulk Wave) and has zero coupling to other modes. It is dominantly a Shear Horizontal (SH) bulk wave and has a low temperature coefficient. Its major disadvantage is a high insertion loss as it changes from SSBW to love mode. When a film material is deposited on the surface it should load the substrate which means the speed of propagation in the film is less than in the substrate. In this case the mode of propagation changes to Love mode. When metal oxides films are deposited on the substrate the insertion loss is decreased as the mode of operation changes from SSBW to Love mode. Its main advantage is a lower insertion loss as it decreases from SSBW to Love mode.
Other suitable substrates are the substrates that allow the generation of leaky SAWs. These include LST quartz, 64 YX-LiNbO 3 , 41 YX-LiNbO 3 and 36 YX-LiTaO3 substrates.
Other substrates cuts, which allow propagation of Rayleigh or other type of waves, can be used for gas sensing applications. Again addition of an acoustic confining layer increases sensitivity of the device.
Substrates that we have employed and tested are: ST cut quartz, XY and Yz LiNBO 3 , 128 X LiNbO 3 , 110 Bismuth germanium oxide, different cuts of LiTaO 3 , GaAs, langatite and langasite.
Different types of second layers are used: metal compounds, metal oxides, metal nitrides, binary compounds, polymers, nano-particle compounds and amorphous materials.
One of the simplest, most economic and most reliable methods of operating a SAW device is to place it in a feedback-loop. Implementing this, the system oscillates at a frequency, which is a function of the width of the finger pairs of the SAW device pattern and the speed of propagation of the delay line. A change in the operational frequency of the system is resulted from the change in the acoustic wave propagation speed which itself is changed via the interaction with an analyte.
A biologically sensitive layer is deposited on the second piezo layer of the second SAW device to interact with the appropriate biochemical components to be detected. A gold film may be deposited on the surface. Gold interacts with high affinity to proteins. It can be used with specific antibodies for antigen detection. This deposit can be made on a porous surface as well as a smooth surface. A simple SAW oscillator may contain and amplifier, a SAW device, an output coupler and a means of setting loop phase shift for instance via a length of a coax cable. The saturation of the loop amplifier provides the gain compression. A very important aspect in the design and implementation of a SAW sensing system, which operates based on an oscillator, is the stability of the frequency. Different types of phenomenon may cause a frequency deviations from the base frequency in a sensing system. They can be categorized as follow:
1—Random deviations generated by random noise 2—Drift as a constant frequency shift. This can be a short term or a long term drift 3—Electromagnetic effects. Although shielding dramatically reduces this effect but affinity of any metal or material with high permittivity to the system may generate a frequency change 4—Noise due to the mechanical component of the system such as pumps and injection of the analyte 5—Frequency changes caused by warming up of the electronic circuits and random noise generated in them
The frequency stability for a SAW oscillation system is divided into systematic and random categories:
1. Systematic are the predictable effects 2. Random effects are different regarding prediction and spectral densities than systematic effects
Random noises are generally difficult to quantify, as they are not a state of frequency which is changing at a specific time period. Furthermore, random noise value strongly depends on the number of samples and the total length of measurement. For the study of random noise, the spectra of the frequency are normally the most common parameters to inspect.
Among random noises, the parameter which has the most important effect on oscillation frequency, is the change in temperature. It has effect both on the SAW device and on the electronic components of the loop's amplifier.
The characteristics of the temperature coefficient of frequency is largely dependant on the cut of the crystal. Generally, the frequency change generated by the temperature change can be dramatically suppressed by employing a dual delay line device and looking at the difference of the two oscillations.
DETAILED DESCRIPTION OF INVENTION
The present invention adds to the proposals disclosed in WO 02/095940 the content of which is incorporated herein by reference.
FIG. 1 is a cross section of a saw sensor to which the invention is applicable;
FIG. 2 is a schematic illustration of a preferred sensor and analyser of this invention;
FIG. 3 illustrates the frequency shift performance of the invention;
FIG. 4 illustrates the random noise of a SAW device of the invention;
FIG. 5 illustrates the band width reduction achieved by the present invention;
FIG. 6 illustrates the response of the sensor of this invention to hydrogen gas;
FIG. 7 illustrates the response of the sensor of this invention to carbon monoxide gas;
FIG. 8 illustrates the response of the sensor of this invention to nitrogen dioxide gas;
FIG. 9 illustrates the response of the sensor of this invention to biochemicals in a liquid;
FIG. 10 illustrates the effect of ZnO SiO 2 layers on frequency shift;
FIG. 11 illustrates the mass sensitivity of layered SAW devices based on 36 LiTaO 3 and 64 LiNbO 3 with ZnO guiding layers;
FIG. 12 illustrates the effect of conductivity change vs layer thickness.
This invention provides piezoelectric layers on piezoelectric substrates. The Substrate's cut belongs to a class of crystal cuts that support Surface Skimming Bulk Wave (SSBW) and leaky wave for liquid sensing applications and other cuts for gas sensing applications. The layers are of different of piezoelectric materials that can be deposited as a highly directional film on the substrate, which let acoustic waves propagate onto its environment. Speed of propagation of acoustic wave in the layers must be less than the substrate to support Love mode of propagation, otherwise it allows other modes of propagation as well.
In FIG. 1 a first wave generating transducer 3 and a first receiving transducer 4 are fabricated onto the surface of a piezoelectric substrate 1 . The transducers 3 and 4 are any suitable interdigital transducer used in SAW devices. The wave transmitting layer 5 , a piezoelectric layer, is fabricated onto the substrate 1 such that the transducers 3 and 4 lie between the substrate 1 and the layer 5 .
A sensing layer 6 is deposited on to the wave propagation layer 5 to form a surface which is physically, chemically or biologically active, selectively to agents in the liquid or gaseous media to which the surface 6 is exposed. The surface may be treated to detect any biological target. For quality control in food production the surface can be treated to detect quantitatively the presence of Salmonella, E Coli, or other enteric pathogens. For environmental monitoring pathogens such as legionella can be detected.
The transitional layer 9 is preferably an acoustically sensitive layer such as SiO 2 which increases the velocity shift and as a result increases the electromechanical coupling factor. The transition layer 9 lies between the wave transmitting layer 5 and the substrate 1 so that the distance between the first IDT and layer 5 is increased to facilitate a higher coupling coefficient and reduce the acoustic wave transmission energy loss which otherwise occur. The protective layer 10 lies between the sensing layer 6 and the piezo layer 5 to protect layer 5 from damage. The protective layer 10 may be SiO 2 , other metal oxides, metal compounds or polymers.
In FIG. 2 the SAW device of this invention is shown in a detector device.
In FIG. 2 second wave generating transducer 7 and a second receiving transducer 8 above the substrate layer and below the wave transmitting layer and near the first generating transducers 3 and receiving transducers 4 . Both sets of transducers are located on the same substrate. No sensing layer is located above the second set of transducers 7 and 8 so that they can function as a reference sensor.
A frequency counter 11 determines frequency of the output signals and a computing device 12 calculates the concentration of the detectable components in the liquid or gaseous media. The output from the first receiver transducer 4 contains the sensing signal which is a consequence of the interaction between the sensing layer and the target molecules. The output from the second receiving transducer 8 contains only the operational characteristics of the sensing device because thee is no sensing layer 6 above it. This enables the analyser to compute accurately a signal indicative of the concentration of the target molecule.
There are many parameters which effects the long term stability. Generally a final bake of the device makes a SAW device more stable. It is believed that the diffusion of metal into crystal is reduced in time with such a bake. This bake may generate a saturated diffusion level which reduces the room temperature diffusion.
The spectral density of frequency fluctuations S(f) is the magnitude of the mean square frequency fluctuation in a 1 Hz bandwidth. Another parameter used for quantifying random-frequency fluctuations is Allan variance. Allan parameter is the average value of one half of the square of the fractional change in frequency between two adjacent frequency measurements.
The issue of frequency deviation for the SAW sensors has been investigated. The differences for a SAW sensing system are as follow:
1—The system is in touch with an analyte. This analyte can be either gas or liquid. Contact with such materials may generate extra noise in the system. It results in more unpredictable behaviour of the system. 2—Generally a layered SAW device is used for liquid sensing applications. Most of the available studies so far are conducted for blank SAW devices.
Even for a blank device, the source of the frequency noise in SAW oscillators is not generally well understood. Contact with different analytes dramatically increases the complexity of the system.
In this invenstion the following methods were employed to reduce noise of the system and increase the frequency stability of the oscillation frequency:
1. Adding Gratings Between Transducers
Layered SAW devices are fabricated on to a crystal cut that allows the propagation of surface transverse wave (STW) (Leaky SAW and SSBW are in STW family). STW devices have:
Low device loss High intrinsic Q Low 1/f noise and low vibration sensitivity
Currently, STW based resonators are widely used in modern communication and wireless remote sensing, weapon guiding systems.
By the deposition of a guiding film a layered SAW device is fabricated. The way to move to fabrication of a stable sensor is to design a high Q SH resonator.
The SH-type acoustic waves are excited by means of IDTs in a direction perpendicular to X-axis on selected temperature compensated rotated Y-orientation on the piezoelectric substrate. If IDTs are separated by a free surface from each other then SH-wave is a SSBW (surface skimming bulk wave) or leaky wave. For these modes of propagations the power is radiate into the bulk of the crystal, which increases the insertion loss. If a metal strip grating with a period equal to that of the IDTs is depostited between IDTs it slows down the SSBW and leaky waves and changed them to STW. The wave energy is confined onto the surface and does not dissipate into the bulk of the device.
In this invention the grating may be patterned either in between the guiding layers or on the surface of the SAW sensors. In both cases the insertion losses are decreased more than 15 dB.
2. Optimising Material Choice (For Example, the Use of Zinc Oxide)
Combination of different materials as the guiding layers and the substrate play a significant role in designing the sensitivity of the device. A layer with the shear horizontal speed of propagation less than that of the substrate usually confines the energy of acoustic waves into the layer. This near the surface energy increases the penetration of acoustic waves into the sensitive layer and target analytes. As a result, increasing the sensitivity of the device.
SAW wafers that allow the propagation of SSBW or leaky wave have to be employed for the fabrications of such devices. The guiding layers can be piezoelectric materials such as ZnO or non-piezoelectric materials such as SiO 2 and Si 3 N 4 .
3. The Number of Reflectors
Adding Reflectors reduces the bandwidth in a SAW device. This will increase the Q of the device, which has a dramatic effect on the signal to noise ratio of the operating system. Adding reflectors decreases the bandwidth of the device. Adding more than 50 reflectors for SAW devices based on LiTaO3 and LiNbO3 substrates have increased the Q of the devices up to one order of magnitude. For ST-cut quartz based devices, more than 150 reflectors are required but it increases the Q of the device up to 15 times.
4. Changing the Q of the Device by Changing the Cavity Length
Cavity length increases the Q of the device. For a better frequency stability the delay line should have a long delay time as possible. To ensure that only one frequency can satisfy the oscillation conditions at any given time, the combined length of the two transducers should be approximately no less than 90 percent of the centre-to-centre distance of the two transducers. The number of fingers in each transducers may be limited to approximately 120. Additional fingers can be used to achieve lower insertion loss, but this increases the undesirable influence of metal on turnover temperature and triple transit reflections.
A number of factors, such as propagation loss, physical size and phase error between groups of fingers contribute to limiting the length of the SAW transducer. At 400 MHz and achievable delay time for a single-mode delay line is about 4μ seconds.
Another advantage of large cavity size is that it increases the power handling capability of the resonator.
5. Fabricate both Devices (the Reference and the Sensor) on the Same Substrate.
This will dramatically decrease the environmental effects. Noises have generally the same effect on both sensor and reference oscillation frequencies and shift them with an equal magnitude. Substraction of these two frequency suppress the effect of environmental noise on the system.
6. Employing Dependant Amplifiers
The reference and sensor are better to be run by dependant amplifiers. The inventors have used arrays of transistors to reduce the effect of temperature on is the gain of the transistors and the environmental noise. When transistors are fabricated onto the same substrates then they show the same change in their gain, specially as temperature drifts.
Though the SAW device has by far the largest delay time of all oscillator components the other components play a significant role in the frequency stability of the oscillator.
In comparison to BAW resonators, SAW devices have one or two order of magnitude lower Q, as a result the influence of frequency stability of electronics is greater. To reduce the effect of stability of loop amplifier should have a large bandwidth. Employment of a negative feedback may help. It is also convenient to use a 50 ohm environment.
The best performance is obtained if bipolar silicon transistors are used as they give lower flicker noise than FETs. Their performance should not be sensitive to a source or load which is not exactly 50 ohm as in most cases SAW devices show different impedance than that of what they are designed for.
7. Optimising the Aperture Size
Aperture size has an important role when the sensor is operating in contact with a liquid. A typical delay line, in air, will have an insertion loss of approximately 20 dB if 120 fingers are used in each transducers and the acoustic aperture is approximately 200 wavelengths.
In contact with liquid the phase shift of the SAW device decreases. A large aperture compensates such a decrease.
8. Grooved Gratings
Grooved gratings usually give better frequency stability than metal grating since the only metal in the active acoustic area comes from the transducers. Despite such an advantage a larger cost may reduce the attractiveness of this method.
9. Device Packaging and Sensitivity to Vibration
The long term frequency stability related to the effect of analyte onto the surface of the SAW device. Ultra clean liquid is required when test for the long term SAW stability is tested. Otherwise a continuous drift is observed.
The vibration sensitivity is strongly dependant on the details of how the SAW device is mounted and packaged. Although normally the magnitude of vibration is small compared to temperature effects and long term drifts. Change in pressure of the liquid cell has a significant effect on the device. Even the pressure can be changed by small drops of liquid trickling from the outlet of a liquid delivery system.
The behaviour of the sensor of this invention is shown graphically in FIGS. 3 to 9 . FIG. 3 shows the warming up of a SAW sensing system with and without applying the enhancement of the invention. Random noise is less and drift is smaller. System reaches a stable condition in a shorter time. FIG. 4 shows the random noise of the enhanced system of this invention.
FIG. 5 illustrates the reduction of the bandwidth of a SAW device before and after introducing the changes. FIG. 5A shows the insertion loss of a SAW device before introducing the enhancements. FIG. 5B shows the insertion loss of a SAW device after introducing the enhancements. Bandwidth is at least 10 times smaller.
FIG. 6 illustrates the response of the layered SAW sensor (Structure: LiTaO 3 /ZnO/WO 3 /Au) to hydrogen gas.
FIG. 7 illustrates the response of the layered SAW sensor (Structure: LiTaO 3 /ZnO/WO 3 /Au) to CO gas.
FIG. 8 illustrates the response of the layered SAW sensor (Structure: LiNbO 3 /ZnO/InO x (20 nm)) to NO 2 gas.
FIG. 9 illustrates the response of the sensor of this invention to biochemicals in a liquid. The system shows a freq response linear to mass addition of the analyte in the solution for masses less than 500 ng for IgNAR. 100 ng, 200 ng, 200 ng and 500 ng of IgNAR has been introduced to the cell and then thoroughly washed.
COMPARATIVE EXAMPLES
Passive layers such as SiO 2 thin films are inefficient on 36 LiTaO 3 and Piezoelectric thin films such as ZnO have a better performance.
To show the mass sensitivity for SiO 2 layer different thicknesses of SiO 2 layers were deposited. The frequency shifts were measured.
On an approximately 100 MHz device the frequency shift is only 600 kHz for each μm of SiO 2 as shown in FIG. 10
As can be seenin FIG. 10 the frequency shift for a 1.5 μm ZnO/36 LiTaO 3 device is approximately 3 MHz but for a 3 μm SiO 2 devices is approximately 1.2 MHz.
The frequency shift for a 1.5 μm SiO 2 device is approximately 900 kHz
According to the measurements the ZnO/36 LiTaO 3 device is between 2.5 to 6 times more mass sensitive than SiO 2 /36 LiTaO 3 device depending on the layer thickness and the type of mass added.
Mass sensitivity comparison between ZnO/64° LiNbO 3 and ZnO/36° LiTaO 3 as two typical substrates for the fabrication of layered SAW devices have been presented.
As can be seen in FIG. 11 , the thickness for obtaining the optimum mass sensitivity for 64° LiNbO 3 is less than 36°LiTaO 3 . At this optimum thickness, the 64° LiNbO 3 is about 2.5 times more mass sensitive.
The advantages of 64° LiNbO 3 over 36° LiTaO 3 are:
1—ZnO layer is smaller 2—Mass sensitivity is larger 3—It can be fabricated on a smaller wafer area as the piezoelectric constant coefficient is larger and makes the structure smaller
However the temperature coefficient of frequency is larger for LiNbO 3 . The ZnO layer on both sides has to have the exact thickness to eliminate the effect of temperature change
The effect of conductivity change vs. the thickness of layer is shown in FIG. 12 Substrate 36 LiTaO 3 and layer is ZnO. WO 3 has been used as the selective layer to H 2 gas. 0.5% and 1% H 2 gas in air has been used in the measurements.
Magnitude of frequency shift vs ZnO thickness when exposed to H 2 . The device structure is ZnO/36 LiTaO 3 . The operational frequency is approximately 200 MHz.
FIG. 12 shows that the thickness of the layer has a significant effect on the conductivity and charge response of the device. Although this example is for gas sensing, the results are also applicable for the surface conductivity change which may occur in bio-sensing applications. The response in a bio-sensing situation will be some unknown combination of mass and conductivity contributions.
Those skilled in the art will realise that variations and modifications may be made to the invention as described without departing from the core teachings of the invention. | A surface acoustic wave sensor which incorporates: a) a first layered SAW device consisting of a piezoelectric crystal such as lithium niobate or lithium tantalate with interdigital electrodes on its surface, and second piezoelectric layer such as zinc oxide over said interdigital electrodes b) a second layered SAW device consisting of a piezoelectric crystal with interdigital electrodes on its surface, a second piezoelectric layer over said interdigital electrodes and an analyte sensitive surface such as gold on said second piezoelectric layer c) both saw devices are fabricated on the same substrate d) reflectors are located adjacent the interdigital electrodes in each saw device to reduce the bandwidth of the device e) the resonator circuits of each saw sensor incorporate amplifiers which are dependent. | Identify the most important claim in the given context and summarize it | [
"This application is the National Stage of International Application Ser.",
"No. PCT/AU2005/000244 filed on Feb. 25, 2005;",
"and this application claims priority of application Ser.",
"No. 2004900942 filed in Australia on Feb. 26, 2004 under 35 U.S.C. § 119;",
"the entire contents of all are hereby incorporated by reference.",
"This invention relates to improvements in Surface Acoustic Wave [SAW] devices and particularly layered SAW devices used as sensors.",
"BACKGROUND OF THE INVENTION SAW devices are usually used in a closed loop with an amplifier to make an oscillator.",
"There are patents which describes setting up a stable oscillator using a SAW device to generate clock pulses for electronic circuits.",
"U.S. Pat. No. 3,979,697 discloses an oscillator in which the “tank circuit”",
"or feedback element is a surface acoustic wave (SAW) bandpass filter (delay line).",
"U.S. Pat. No. 4,868,524 discloses an RF circuit to generate a stable carrier signal using a Voltage Controlled Saw Oscillator.",
"U.S. Pat. No. 5,126,694 discloses A SAW stabilized oscillator includes a phase locking circuit which is phase locked to a lower frequency reference signal having an odd order difference with respect to the fundamental frequency of the SAW oscillator.",
"SAW devices have been used as sensors in liquid and gaseous environments.",
"U.S. Pat. No. 4,562,371 discloses a SAW device comprising a ZnO piezo layer on a cut crystalline silicon substrate that propagates Rayleigh waves.",
"The surface acoustic waves polarizes in 3 directions and can be classified as longitudinal wave motion, Normal waves or shear horizontal waves.",
"A class of shear horizontal [SH] waves are called Love waves which are propagated in layered devices that concentrate the wave energy in a highly confined region near to the surface.",
"Rayleigh wave sensors have been useful in gaseous environments but they are not suitable for liquid environments because the surface-normal displacement causes strong radiative loss into the liquid.",
"For sensing in liquids shear horizontal [SH] polarised wave modes are preferred since the particle displacement is parallel to the device surface and normal to the direction of propagation.",
"This allows a wave to propagate in contact with a liquid without coupling excessive acoustic energy into the liquid.",
"However the SH wave is distributed through the substrate and therefore does not have the same sensitivity as the SAW.",
"For increased sensitivity Love waves which are SH-polarised guided surface waves may be used.",
"The waves propagate in a layered structure consisting of a piezoelectric substrate and a guiding layer which couples the elastic waves generated in the substrate to the near surface.",
"They are extremely sensitive to surface perturbations due to the energy confinement to the near surface.",
"By observing the magnitude of perturbations it is possible to measure the strength of the interaction.",
"The interactions may be caused by mass density, elastic stiffness, liquid viscosity, electric and dielectric properties.",
"The more sensitive is the device the smaller the quantities that can be measured.",
"U.S. Pat. Nos. 5,130,257, 5,216,312, 5,283,037 and 5,321,331 disclose love mode SAW sensors used in liquid environments.",
"The love waves are produced by cutting the piezo electric material such as lithium niobate, lithium tantalate or quartz to couple energy from the interdigital transducers [IDT's] of the SAW device into shear transverse or love waves that enable the wave energy to be trapped at the substrate surface.",
"U.S. Pat. No. 5,705,399 discloses a SAW sensor for liquid environments having an AT cut quartz piezo substrate with electrodes connected to a first side in contact with a liquid and a second side that is not in contact.",
"The sensor may be used to detect biological species such as antigens.",
"WO02/095940 discloses a love mode SAW sensor using a piezo layer of ZnO on a piezo electric quartz crystal.",
"To improve the sensitivity of sensors the stability of the frequency of the device needs to be addressed.",
"U.S. Pat. No. 6,122,954 discloses a SAW sensor with a resonant frequency range of 200 to 2000 MHz and a temperature control system.",
"It is an object of this invention to improve the reliability of SAW sensors and to optimise the operational performance of the sensors.",
"BRIEF DESCRIPTION OF THE INVENTION To this end the present invention provides a surface acoustic wave sensor which incorporates a) a first layered SAW device consisting of a piezoelectric crystal with interdigital electrodes on its surface, and second piezoelectric layer over said interdigital electrodes b) a second layered SAW device consisting of a piezoelectric crystal with interdigital electrodes on its surface, a second piezoelectric layer over said interdigital electrodes and an analyte sensitive surface on said second piezoelectric layer c) both SAW devices are fabricated on the same substrate d) reflectors are located adjacent the interdigital electrodes in each saw device to reduce the bandwidth of the device e) the resonator circuits of each saw sensor incorporate amplifiers which are dependent.",
"When the SAW device interacts with a target analytes the operating frequency changes.",
"The change of operating frequency is proportional to the magnitude of the target analyte in the environment.",
"The oscillation system needs to have a high Q and a stable frequency response.",
"By using the first layered SAW device as a reference sensor and fabricating them on the same substrate the effect of environmental noise can be reduced.",
"By using reflectors to reduce the bandwidth the Q of the devices is increased.",
"Preferably the piezoelectric substrate is cut for propagation of Love mode waves and may be quartz crystal, lithium Niobate [LiNbO 3 ], lithium tantalate [LiTaO 3 ], langasite or langatite.",
"Preferably the second layer is a piezoelectric film such as layer is zinc oxide, AlN LiTaO3, LiTaO3 or quartz The second layer can be a non-piezoelectric which has a capability to confine the acoustic energy with itself such as silicon nitride, different types of metal oxides, polymers or metal compounds.",
"A preferred piezo substrate is 90° rotated ST-cut quartz crystal which has a propagation speed of 5000 m/s and the dominant wave is SSBW (Surface Skimming Bulk Wave) and has zero coupling to other modes.",
"It is dominantly a Shear Horizontal (SH) bulk wave and has a low temperature coefficient.",
"Its major disadvantage is a high insertion loss as it changes from SSBW to love mode.",
"When a film material is deposited on the surface it should load the substrate which means the speed of propagation in the film is less than in the substrate.",
"In this case the mode of propagation changes to Love mode.",
"When metal oxides films are deposited on the substrate the insertion loss is decreased as the mode of operation changes from SSBW to Love mode.",
"Its main advantage is a lower insertion loss as it decreases from SSBW to Love mode.",
"Other suitable substrates are the substrates that allow the generation of leaky SAWs.",
"These include LST quartz, 64 YX-LiNbO 3 , 41 YX-LiNbO 3 and 36 YX-LiTaO3 substrates.",
"Other substrates cuts, which allow propagation of Rayleigh or other type of waves, can be used for gas sensing applications.",
"Again addition of an acoustic confining layer increases sensitivity of the device.",
"Substrates that we have employed and tested are: ST cut quartz, XY and Yz LiNBO 3 , 128 X LiNbO 3 , 110 Bismuth germanium oxide, different cuts of LiTaO 3 , GaAs, langatite and langasite.",
"Different types of second layers are used: metal compounds, metal oxides, metal nitrides, binary compounds, polymers, nano-particle compounds and amorphous materials.",
"One of the simplest, most economic and most reliable methods of operating a SAW device is to place it in a feedback-loop.",
"Implementing this, the system oscillates at a frequency, which is a function of the width of the finger pairs of the SAW device pattern and the speed of propagation of the delay line.",
"A change in the operational frequency of the system is resulted from the change in the acoustic wave propagation speed which itself is changed via the interaction with an analyte.",
"A biologically sensitive layer is deposited on the second piezo layer of the second SAW device to interact with the appropriate biochemical components to be detected.",
"A gold film may be deposited on the surface.",
"Gold interacts with high affinity to proteins.",
"It can be used with specific antibodies for antigen detection.",
"This deposit can be made on a porous surface as well as a smooth surface.",
"A simple SAW oscillator may contain and amplifier, a SAW device, an output coupler and a means of setting loop phase shift for instance via a length of a coax cable.",
"The saturation of the loop amplifier provides the gain compression.",
"A very important aspect in the design and implementation of a SAW sensing system, which operates based on an oscillator, is the stability of the frequency.",
"Different types of phenomenon may cause a frequency deviations from the base frequency in a sensing system.",
"They can be categorized as follow: 1—Random deviations generated by random noise 2—Drift as a constant frequency shift.",
"This can be a short term or a long term drift 3—Electromagnetic effects.",
"Although shielding dramatically reduces this effect but affinity of any metal or material with high permittivity to the system may generate a frequency change 4—Noise due to the mechanical component of the system such as pumps and injection of the analyte 5—Frequency changes caused by warming up of the electronic circuits and random noise generated in them The frequency stability for a SAW oscillation system is divided into systematic and random categories: 1.",
"Systematic are the predictable effects 2.",
"Random effects are different regarding prediction and spectral densities than systematic effects Random noises are generally difficult to quantify, as they are not a state of frequency which is changing at a specific time period.",
"Furthermore, random noise value strongly depends on the number of samples and the total length of measurement.",
"For the study of random noise, the spectra of the frequency are normally the most common parameters to inspect.",
"Among random noises, the parameter which has the most important effect on oscillation frequency, is the change in temperature.",
"It has effect both on the SAW device and on the electronic components of the loop's amplifier.",
"The characteristics of the temperature coefficient of frequency is largely dependant on the cut of the crystal.",
"Generally, the frequency change generated by the temperature change can be dramatically suppressed by employing a dual delay line device and looking at the difference of the two oscillations.",
"DETAILED DESCRIPTION OF INVENTION The present invention adds to the proposals disclosed in WO 02/095940 the content of which is incorporated herein by reference.",
"FIG. 1 is a cross section of a saw sensor to which the invention is applicable;",
"FIG. 2 is a schematic illustration of a preferred sensor and analyser of this invention;",
"FIG. 3 illustrates the frequency shift performance of the invention;",
"FIG. 4 illustrates the random noise of a SAW device of the invention;",
"FIG. 5 illustrates the band width reduction achieved by the present invention;",
"FIG. 6 illustrates the response of the sensor of this invention to hydrogen gas;",
"FIG. 7 illustrates the response of the sensor of this invention to carbon monoxide gas;",
"FIG. 8 illustrates the response of the sensor of this invention to nitrogen dioxide gas;",
"FIG. 9 illustrates the response of the sensor of this invention to biochemicals in a liquid;",
"FIG. 10 illustrates the effect of ZnO SiO 2 layers on frequency shift;",
"FIG. 11 illustrates the mass sensitivity of layered SAW devices based on 36 LiTaO 3 and 64 LiNbO 3 with ZnO guiding layers;",
"FIG. 12 illustrates the effect of conductivity change vs layer thickness.",
"This invention provides piezoelectric layers on piezoelectric substrates.",
"The Substrate's cut belongs to a class of crystal cuts that support Surface Skimming Bulk Wave (SSBW) and leaky wave for liquid sensing applications and other cuts for gas sensing applications.",
"The layers are of different of piezoelectric materials that can be deposited as a highly directional film on the substrate, which let acoustic waves propagate onto its environment.",
"Speed of propagation of acoustic wave in the layers must be less than the substrate to support Love mode of propagation, otherwise it allows other modes of propagation as well.",
"In FIG. 1 a first wave generating transducer 3 and a first receiving transducer 4 are fabricated onto the surface of a piezoelectric substrate 1 .",
"The transducers 3 and 4 are any suitable interdigital transducer used in SAW devices.",
"The wave transmitting layer 5 , a piezoelectric layer, is fabricated onto the substrate 1 such that the transducers 3 and 4 lie between the substrate 1 and the layer 5 .",
"A sensing layer 6 is deposited on to the wave propagation layer 5 to form a surface which is physically, chemically or biologically active, selectively to agents in the liquid or gaseous media to which the surface 6 is exposed.",
"The surface may be treated to detect any biological target.",
"For quality control in food production the surface can be treated to detect quantitatively the presence of Salmonella, E Coli, or other enteric pathogens.",
"For environmental monitoring pathogens such as legionella can be detected.",
"The transitional layer 9 is preferably an acoustically sensitive layer such as SiO 2 which increases the velocity shift and as a result increases the electromechanical coupling factor.",
"The transition layer 9 lies between the wave transmitting layer 5 and the substrate 1 so that the distance between the first IDT and layer 5 is increased to facilitate a higher coupling coefficient and reduce the acoustic wave transmission energy loss which otherwise occur.",
"The protective layer 10 lies between the sensing layer 6 and the piezo layer 5 to protect layer 5 from damage.",
"The protective layer 10 may be SiO 2 , other metal oxides, metal compounds or polymers.",
"In FIG. 2 the SAW device of this invention is shown in a detector device.",
"In FIG. 2 second wave generating transducer 7 and a second receiving transducer 8 above the substrate layer and below the wave transmitting layer and near the first generating transducers 3 and receiving transducers 4 .",
"Both sets of transducers are located on the same substrate.",
"No sensing layer is located above the second set of transducers 7 and 8 so that they can function as a reference sensor.",
"A frequency counter 11 determines frequency of the output signals and a computing device 12 calculates the concentration of the detectable components in the liquid or gaseous media.",
"The output from the first receiver transducer 4 contains the sensing signal which is a consequence of the interaction between the sensing layer and the target molecules.",
"The output from the second receiving transducer 8 contains only the operational characteristics of the sensing device because thee is no sensing layer 6 above it.",
"This enables the analyser to compute accurately a signal indicative of the concentration of the target molecule.",
"There are many parameters which effects the long term stability.",
"Generally a final bake of the device makes a SAW device more stable.",
"It is believed that the diffusion of metal into crystal is reduced in time with such a bake.",
"This bake may generate a saturated diffusion level which reduces the room temperature diffusion.",
"The spectral density of frequency fluctuations S(f) is the magnitude of the mean square frequency fluctuation in a 1 Hz bandwidth.",
"Another parameter used for quantifying random-frequency fluctuations is Allan variance.",
"Allan parameter is the average value of one half of the square of the fractional change in frequency between two adjacent frequency measurements.",
"The issue of frequency deviation for the SAW sensors has been investigated.",
"The differences for a SAW sensing system are as follow: 1—The system is in touch with an analyte.",
"This analyte can be either gas or liquid.",
"Contact with such materials may generate extra noise in the system.",
"It results in more unpredictable behaviour of the system.",
"2—Generally a layered SAW device is used for liquid sensing applications.",
"Most of the available studies so far are conducted for blank SAW devices.",
"Even for a blank device, the source of the frequency noise in SAW oscillators is not generally well understood.",
"Contact with different analytes dramatically increases the complexity of the system.",
"In this invenstion the following methods were employed to reduce noise of the system and increase the frequency stability of the oscillation frequency: 1.",
"Adding Gratings Between Transducers Layered SAW devices are fabricated on to a crystal cut that allows the propagation of surface transverse wave (STW) (Leaky SAW and SSBW are in STW family).",
"STW devices have: Low device loss High intrinsic Q Low 1/f noise and low vibration sensitivity Currently, STW based resonators are widely used in modern communication and wireless remote sensing, weapon guiding systems.",
"By the deposition of a guiding film a layered SAW device is fabricated.",
"The way to move to fabrication of a stable sensor is to design a high Q SH resonator.",
"The SH-type acoustic waves are excited by means of IDTs in a direction perpendicular to X-axis on selected temperature compensated rotated Y-orientation on the piezoelectric substrate.",
"If IDTs are separated by a free surface from each other then SH-wave is a SSBW (surface skimming bulk wave) or leaky wave.",
"For these modes of propagations the power is radiate into the bulk of the crystal, which increases the insertion loss.",
"If a metal strip grating with a period equal to that of the IDTs is depostited between IDTs it slows down the SSBW and leaky waves and changed them to STW.",
"The wave energy is confined onto the surface and does not dissipate into the bulk of the device.",
"In this invention the grating may be patterned either in between the guiding layers or on the surface of the SAW sensors.",
"In both cases the insertion losses are decreased more than 15 dB.",
"Optimising Material Choice (For Example, the Use of Zinc Oxide) Combination of different materials as the guiding layers and the substrate play a significant role in designing the sensitivity of the device.",
"A layer with the shear horizontal speed of propagation less than that of the substrate usually confines the energy of acoustic waves into the layer.",
"This near the surface energy increases the penetration of acoustic waves into the sensitive layer and target analytes.",
"As a result, increasing the sensitivity of the device.",
"SAW wafers that allow the propagation of SSBW or leaky wave have to be employed for the fabrications of such devices.",
"The guiding layers can be piezoelectric materials such as ZnO or non-piezoelectric materials such as SiO 2 and Si 3 N 4 .",
"The Number of Reflectors Adding Reflectors reduces the bandwidth in a SAW device.",
"This will increase the Q of the device, which has a dramatic effect on the signal to noise ratio of the operating system.",
"Adding reflectors decreases the bandwidth of the device.",
"Adding more than 50 reflectors for SAW devices based on LiTaO3 and LiNbO3 substrates have increased the Q of the devices up to one order of magnitude.",
"For ST-cut quartz based devices, more than 150 reflectors are required but it increases the Q of the device up to 15 times.",
"Changing the Q of the Device by Changing the Cavity Length Cavity length increases the Q of the device.",
"For a better frequency stability the delay line should have a long delay time as possible.",
"To ensure that only one frequency can satisfy the oscillation conditions at any given time, the combined length of the two transducers should be approximately no less than 90 percent of the centre-to-centre distance of the two transducers.",
"The number of fingers in each transducers may be limited to approximately 120.",
"Additional fingers can be used to achieve lower insertion loss, but this increases the undesirable influence of metal on turnover temperature and triple transit reflections.",
"A number of factors, such as propagation loss, physical size and phase error between groups of fingers contribute to limiting the length of the SAW transducer.",
"At 400 MHz and achievable delay time for a single-mode delay line is about 4μ seconds.",
"Another advantage of large cavity size is that it increases the power handling capability of the resonator.",
"Fabricate both Devices (the Reference and the Sensor) on the Same Substrate.",
"This will dramatically decrease the environmental effects.",
"Noises have generally the same effect on both sensor and reference oscillation frequencies and shift them with an equal magnitude.",
"Substraction of these two frequency suppress the effect of environmental noise on the system.",
"Employing Dependant Amplifiers The reference and sensor are better to be run by dependant amplifiers.",
"The inventors have used arrays of transistors to reduce the effect of temperature on is the gain of the transistors and the environmental noise.",
"When transistors are fabricated onto the same substrates then they show the same change in their gain, specially as temperature drifts.",
"Though the SAW device has by far the largest delay time of all oscillator components the other components play a significant role in the frequency stability of the oscillator.",
"In comparison to BAW resonators, SAW devices have one or two order of magnitude lower Q, as a result the influence of frequency stability of electronics is greater.",
"To reduce the effect of stability of loop amplifier should have a large bandwidth.",
"Employment of a negative feedback may help.",
"It is also convenient to use a 50 ohm environment.",
"The best performance is obtained if bipolar silicon transistors are used as they give lower flicker noise than FETs.",
"Their performance should not be sensitive to a source or load which is not exactly 50 ohm as in most cases SAW devices show different impedance than that of what they are designed for.",
"Optimising the Aperture Size Aperture size has an important role when the sensor is operating in contact with a liquid.",
"A typical delay line, in air, will have an insertion loss of approximately 20 dB if 120 fingers are used in each transducers and the acoustic aperture is approximately 200 wavelengths.",
"In contact with liquid the phase shift of the SAW device decreases.",
"A large aperture compensates such a decrease.",
"Grooved Gratings Grooved gratings usually give better frequency stability than metal grating since the only metal in the active acoustic area comes from the transducers.",
"Despite such an advantage a larger cost may reduce the attractiveness of this method.",
"Device Packaging and Sensitivity to Vibration The long term frequency stability related to the effect of analyte onto the surface of the SAW device.",
"Ultra clean liquid is required when test for the long term SAW stability is tested.",
"Otherwise a continuous drift is observed.",
"The vibration sensitivity is strongly dependant on the details of how the SAW device is mounted and packaged.",
"Although normally the magnitude of vibration is small compared to temperature effects and long term drifts.",
"Change in pressure of the liquid cell has a significant effect on the device.",
"Even the pressure can be changed by small drops of liquid trickling from the outlet of a liquid delivery system.",
"The behaviour of the sensor of this invention is shown graphically in FIGS. 3 to 9 .",
"FIG. 3 shows the warming up of a SAW sensing system with and without applying the enhancement of the invention.",
"Random noise is less and drift is smaller.",
"System reaches a stable condition in a shorter time.",
"FIG. 4 shows the random noise of the enhanced system of this invention.",
"FIG. 5 illustrates the reduction of the bandwidth of a SAW device before and after introducing the changes.",
"FIG. 5A shows the insertion loss of a SAW device before introducing the enhancements.",
"FIG. 5B shows the insertion loss of a SAW device after introducing the enhancements.",
"Bandwidth is at least 10 times smaller.",
"FIG. 6 illustrates the response of the layered SAW sensor (Structure: LiTaO 3 /ZnO/WO 3 /Au) to hydrogen gas.",
"FIG. 7 illustrates the response of the layered SAW sensor (Structure: LiTaO 3 /ZnO/WO 3 /Au) to CO gas.",
"FIG. 8 illustrates the response of the layered SAW sensor (Structure: LiNbO 3 /ZnO/InO x (20 nm)) to NO 2 gas.",
"FIG. 9 illustrates the response of the sensor of this invention to biochemicals in a liquid.",
"The system shows a freq response linear to mass addition of the analyte in the solution for masses less than 500 ng for IgNAR.",
"100 ng, 200 ng, 200 ng and 500 ng of IgNAR has been introduced to the cell and then thoroughly washed.",
"COMPARATIVE EXAMPLES Passive layers such as SiO 2 thin films are inefficient on 36 LiTaO 3 and Piezoelectric thin films such as ZnO have a better performance.",
"To show the mass sensitivity for SiO 2 layer different thicknesses of SiO 2 layers were deposited.",
"The frequency shifts were measured.",
"On an approximately 100 MHz device the frequency shift is only 600 kHz for each μm of SiO 2 as shown in FIG. 10 As can be seenin FIG. 10 the frequency shift for a 1.5 μm ZnO/36 LiTaO 3 device is approximately 3 MHz but for a 3 μm SiO 2 devices is approximately 1.2 MHz.",
"The frequency shift for a 1.5 μm SiO 2 device is approximately 900 kHz According to the measurements the ZnO/36 LiTaO 3 device is between 2.5 to 6 times more mass sensitive than SiO 2 /36 LiTaO 3 device depending on the layer thickness and the type of mass added.",
"Mass sensitivity comparison between ZnO/64° LiNbO 3 and ZnO/36° LiTaO 3 as two typical substrates for the fabrication of layered SAW devices have been presented.",
"As can be seen in FIG. 11 , the thickness for obtaining the optimum mass sensitivity for 64° LiNbO 3 is less than 36°LiTaO 3 .",
"At this optimum thickness, the 64° LiNbO 3 is about 2.5 times more mass sensitive.",
"The advantages of 64° LiNbO 3 over 36° LiTaO 3 are: 1—ZnO layer is smaller 2—Mass sensitivity is larger 3—It can be fabricated on a smaller wafer area as the piezoelectric constant coefficient is larger and makes the structure smaller However the temperature coefficient of frequency is larger for LiNbO 3 .",
"The ZnO layer on both sides has to have the exact thickness to eliminate the effect of temperature change The effect of conductivity change vs.",
"the thickness of layer is shown in FIG. 12 Substrate 36 LiTaO 3 and layer is ZnO.",
"WO 3 has been used as the selective layer to H 2 gas.",
"0.5% and 1% H 2 gas in air has been used in the measurements.",
"Magnitude of frequency shift vs ZnO thickness when exposed to H 2 .",
"The device structure is ZnO/36 LiTaO 3 .",
"The operational frequency is approximately 200 MHz.",
"FIG. 12 shows that the thickness of the layer has a significant effect on the conductivity and charge response of the device.",
"Although this example is for gas sensing, the results are also applicable for the surface conductivity change which may occur in bio-sensing applications.",
"The response in a bio-sensing situation will be some unknown combination of mass and conductivity contributions.",
"Those skilled in the art will realise that variations and modifications may be made to the invention as described without departing from the core teachings of the invention."
] |
[0001] This application claims the priority benefit under 35 U.S.C. section 119 of U.S. Provisional Patent Application No. 60/935,402 entitled “Styrenated Phenol Ethoxylates In Emulsion Polymerization”, filed Aug. 10, 2007, which is in its entirety herein incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to emulsion polymerizing ethylenically unsaturated monomers monomers. This invention also relates to emulsion polymerization of ethylenically unsaturated monomers by using styrenated surfactants as the primary emulsifier. The instant invention also relates to a process for the preparation of a polymer dispersion by free radical polymerization of an aqueous monomer emulsion. The present invention further relates to a method for production of waterborne polymer and copolymer dispersions comprising monomer units derived from at least one polymerizable ethylenically unsaturated monomers. The polymer and copolymer dispersions are obtained in a free radical emulsion polymerization process performed in an aqueous media and in the presence of at least one styrenated surfactant. In a further aspect the present invention refers to the use of said polymer or copolymer dispersion.
BACKGROUND OF THE INVENTION
[0003] Emulsion polymerization is the most important industrial method for manufacture of aqueous dispersion polymers. Emulsion polymerization is typically performed in an aqueous medium in the presence of a surfactant and a water soluble initiator and is usually rapidly producing high molecular weight homo or copolymers at high solids content and low dispersion viscosity. Its application requires the emulsification of the monomer in a medium, usually water, through the use of emulsifiers. These are supplied in addition to the other ingredients that go into most polymerizations, such as the initiator and chain transfer agents. The use and type of emulsifier determines many of the characteristics of the produced polymer or copolymer, which is typically a latex (stable colloidal suspension of polymer particles in a continuous phase, usually water). Moreover, the emulsifier usually cannot be completely removed from the latex. For this reason, and because of the great unpredictability of the efficacy of a given surface-active agent as an emulsifier in polymerization, many compounds that would theoretically be useful are not.
[0004] It is also known that emulsion polymerization requires the use of a surfactant to form a stable emulsion of monomers and to prevent coagulation of the product polymer. Surfactants are generally categorized into two types: either non-polymerizable, or polymerizable, that is co-polymerizable with the monomers for polymer formation. A problem which has arisen with the use of non-polymerizable surfactants is that they remain as a residue in the product polymer and, as they can be extracted by water, they make the product sensitive to water. Surfactants are also categorized as anionic, cationic, non-ionic or switterionic depending on their chemical makeup.
[0005] With the customary emulsion polymerization processes, suitable latices have been difficult to obtain since the latices usually contain particles of varying size and are either too fine or too large. Various proposals have heretofore been made to overcome these difficulties but not with the ultimate success desired. For example, the use of various different emulsifiers and catalysts have been proposed. Also, varying the conditions of polymerization has been suggested. However, in most of these cases, too much coagulation occurred with the resulting latex containing too much coagulum or partially agglomerated particles which precipitate reducing the yield. Further, the shelf life of such latices leave much to be desired. It is desirable to have latices which change very little during storage with respect to viscosity and have and maintain good heat stability.
[0006] The final product resulting from emulsion polymerization is normally an opaque, grey or milky-white dispersion of high molecular weight polymer(s) at a solids content of typically 30-60% in water. Said dispersion typically comprises acrylic, methacrylic and crotonic acid homo and copolymers, methacrylate and acrylate ester homo or copolymers, vinyl acetate homo or copolymers, vinyl and vinylidene chloride homo or copolymers, ethylene homo or copolymers, styrene and butadiene homo or copolymers, acrylamide homo or copolymers, butadiene-acrylonitrile copolymers, styrene-acrolein copolymers and/or where applicable carboxylated versions. Traditional applications for such aqueous dispersions are adhesives, binders for fibres and particulate matter, protective and decorative coatings, dipped goods, foam, paper coatings, backings for carpet and upholstery, modifiers for bitumens and concrete and thread and textile modifiers. More recent applications include biomedical applications as protein immobilisers, visual detectors in immunoassays, as release agents, in electronic applications as photoresists for circuit boards, in batteries, conductive paint, copy machines and as key components in molecular electronic devices.
[0007] Ethoxylated Styrenated Phenols have been widely disclosed as effective and efficient pigment dispersants in a variety of applications. U.S. Pat. No. 6,736,892 (2004) discloses anionic Styrenated Phenol Ethoxylates as pigment dispersants in water based ink and coating applications. US application 0235877 A1 (2005) discloses fatty acid esters of Styrenated Phenol Alkoxylates as effective and efficient pigment dispersants for solvent based systems. U.S. Pat. No. 5,035,785 (1991) discloses nonionic Styrenated Phenol Ethoxylates as effective and efficient pigment dispersants in electrodeposition baths. The dispersants were also found to increase film build and dramatically improve film appearance and maintain the improved film appearance in this application. Thus the utility of Styrenated Phenol Ethoxylates, both anionic and nonionic, in separating and stabilizing pigment particles against aggregation has been well known and demonstrated in both aqueous and non aqueous systems. In these applications, these surfactants are added as part of the formulation comprising the resin used as a binder or film former, the pigment paste or dispersion, and other additives such as coalescing aids, viscosity modifiers, and other additives well know to those familiar with the art.
[0008] In emulsion polymerization of ethylenically unsaturated monomers, it is well known to those familiar with the art that surfactants are necessary and essential ingredients required for the polymerization reaction to occur in the aqueous phase. It is also well know to those familiar with the art that surfactants further function by stabilizing the latex particles against aggregation from shear or mechanical force and also stabilize the latex particles from aggregation due to the addition of electrolyte to the latex. In the emulsion polymerization process, since the radical polymerization takes place inside the surfactant formed micelles, the surfactants in emulsion polymerization are essential components in the manufacture of the latex. (Bejamin B. Kline and George H. Redlich, “The Role of Surfactants in Emulsion Polymerization”, Surfactant Science Series, 26, 1988) It is also well know to those skilled in the art that the selection of surfactant type and level is also the determining factor in many emulsion properties, in particular the particle size of the latex particles. Low particle size is highly desirable in pigmentation and results in higher gloss in the final film or coating.
[0009] We have now found that the Styrenated Phenol Ethoxylates are useful as surfactants in the emulsion polymerization of ethylenically unsaturated monomers. The use of both anionic and nonionic Styrenated Phenol Ethoxylates in the emulsion polymerization process provides latexes with small particle size and small particle size distributions. Furthermore, latexes prepared using Styrenated Phenol Ethoxylates have excellent mechanical and chemical stability. The Styrenated Phenol Ethoxylates of the present invention may also be used in combination with conventional surfactants to improve latex properties.
SUMMARY OF THE INVENTION
[0010] The present invention provides a process for the emulsion polymerization of at least one ethylenically unsaturated monomer containing at least one carbon-to-carbon double bond, said process comprising polymerizing said ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble initiator and a surfactant of the formula:
[0000]
[0000] wherein n=1, 2 or 3; X is 1-100; Z is selected from the group consisting of SO 3 − or PO 3 2− ; and M + is selected from the group consisting of Na + , K + , NH 4 + , and an alkanolamine.
[0011] The present invention also provides a process for the emulsion polymerization of at least one ethylenically unsaturated monomer containing at least one carbon-to-carbon double bond, said process comprising polymerizing said ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble initiator and a surfactant of the formula:
[0000]
[0000] wherein n=1, 2, 3; x is preferably 1-100.
[0012] The instant invention further provides a process for the emulsion polymerization of at least one ethylenically unsaturated monomer containing at least one carbon-to-carbon double bond, said process comprising polymerizing said ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble initiator and a mixture of surfactants of the formula I and II:
[0000]
[0000] wherein n=1, 2, 3; x is preferably 1-100; Z can be either SO 3 − or PO 3 2− , and M + is Na + , K + , NH 4 + , or an alkanolamine.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The present invention is directed towards the emulsion polymerization of ethylenically unsaturated monomers in the presence of a anionic surfactant of formula (I)
[0000]
[0000] where n=1, 2, 3; x is preferably 1-100, more preferably from about 5 to 60, and most preferably from about 5 to 40; Z can be either SO 3 − or PO 3 2− , and M + is Na + , K + , NH 4 + , or an alkanolamine.
[0014] The present invention is further directed towards the emulsion polymerization of ethylenically unsaturated monomers in the presence of a nonionic surfactant of formula (II)
[0000]
[0000] where n=1, 2, 3; X is preferably 1-100. more preferably from about 5 to 60, and most preferably from about 5 to 40.
[0015] The compounds of formulas (I) and (II) may be used separately or in combination in the emulsion polymerization. More commonly they are used in combination. When used in combination, the ratio of compounds of formula (I) to compounds of formula (II) is not limited but is dictated by the desired emulsion properties. Surfactants of formulas (I) and (II) may also be used in combination with other surfactants that are commonly used in the art When used in combination, the ratio of surfactants is not specific but is commonly optimized based on the nature of the ethylenically unsaturated monomers present in a given formulation. The total amount of surfactants of formulas (I) and formula (I) that may be used in the present invention is preferably from about 0.1% to about 20% based on total weight of the monomer, more preferably from about 0.2% to about 10%, and most preferably from about 0.5% to about 7% based on the total weight of the monomer. The compounds of formulas (I) and (II) may also be used in combination with conventional surfactants in order to improve emulsion properties
[0016] Surfactants that are commonly used in the emulsion polymerization process include both anionic and nonionic molecules. Commonly utilized anionic surfactants in the emulsion polymerization process include sodium alkylbenzene sulfonates, alkyldiphenyloxide disulfonates, ethoxylated alkylphenol sulfates and phosphates, alkyl sulfosuccinates, and sulfates and phosphates of fatty alcohols, etc. Commonly utilized nonionic surfactants include linear and branched alcohol ethoxylates, and alkylphenol ethoxylates, particularly octylphenol ethoxylates. When used in combination with other surfactants the ratios are not limited but are also dictated by the desired emulsion properties.
[0017] Suitable monomers that may be polymerized by the practice of the present invention include numerous ethylenically unsaturated monomers such as vinyl monomers or acrylic monomers. Typical vinyl monomers suitable for use in accordance with the present invention include, but are not limited to, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, etc; vinyl aromatic hydrocarbons such as styrene, methyl styrenes, other vinyl aromatics such as vinyl toluenes, vinyl napthalenes, divinyl benzene, etc. Halogenated vinyl monomers such as vinyl chloride, vinylidene chloride, etc. may also be used.
[0018] Suitable acrylic monomers which may be used in accordance with the present invention comprise compounds with acrylic functionality such as alkyl acrylates and methacrylates, acrylate acids and methacrylate acids as well as acrylamides and acrylonitrile. Typical acrylic monomers include, but are not limited to methyl acrylate and methyl methacrylate, ethyl, propyl, and butyl acrylate and methacrylate, benzyl acrylate and methacrylate, cyclohexyl acrylate and methacrylate, decyl and dodecyl acrylate and methacrylate, etc. Other typical acrylic monomers include hydroxy alkyl acrylates and methacrylates such as hydroxypropyl and hydroxyethyl acrylate and methacrylate, acrylic acids such as methacrylic and acrylic acid, and amino acrylates and methacrylates. It will be recognized by those familiar with the art that other unsaturated monomers which are suitable for free radical addition polymerization may also be used in accordance with the present invention.
[0019] Numerous free radical forming compounds are utilized as catalysts in the emulsion polymerization process. Typically compounds used as catalysts are those that from free radicals via thermal decomposition, referred to in the art as “thermal initiators” or combinations of compounds that form free radicals via oxidation/reduction reactions. Such catalysts are combinations of an oxidizing agent and a reducing agent and are commonly referred to in the art as “redox initiators.” Either thermal or redox catalysts may be used in the practice of the present invention.
[0020] Typical catalysts utilized as thermal initiators include persulfates, specifically potassium persulfate, sodium persulfate, ammonium persulfate and the like. Typical redox initiators include combinations of oxidizing agents or initiators such as peroxides, specifically benzoyl peroxide, t-butyl hydroperoxide, lauryl peroxide, hydrogen peroxide, 2,2′-diazobisisobutyronitrile, and the like. Typical reducing agents include sodium bisulfite, sodium formaldehyde sulfoxylate, sodium hydrosulfite, and ascorbic and isoascorbic acid. The catalyst or initiator is employed in an amount preferably from 0.1 to 3 weight percent of the total monomer weight, and most preferably from about 0.1 to 1 weight percent of the total monomer charge.
[0021] Other additives or components which are known to those skilled in the art may also used in accordance with the present invention. These include chain transfer agents, which are used to control molecular weight, additives to adjust pH, and compounds utilized as protective colloids which provide additional stability to the latex particles.
[0022] Any of the conventional methods employed in the emulsion polymerization process may also be used in accordance with the present invention. These include both standard and pre-emulsion monomer addition techniques as well as staged monomer addition.
EXAMPLES
[0023] The following examples and comparative examples are intended to illustrate the usefulness of the invention and are not to be construed as limiting or defining the entire scope of the invention in any way.
[0024] All reactions were carried out in a 1500 mL glass reactor equipped with a four-blade stainless steel agitator, nitrogen gas inlet, thermocouple connected to a digital temperature controller, reflux condenser, and inlets for the addition of monomer mixture and catalyst solutions. Emulsion viscosities were measured using a Brookfield LVT Viscometer using a # 2 spindle at 30 rpm. Particle size measurements were run on a Brookhaven 90Plus Particle Size Analyzer.
[0025] The Styrenated Phenol Ethoxylates of the present invention will be referred to in an abbreviated fashion. For example, the Sodium Sulfate salt of Distyrenated Phenol containing 20 moles of ethylene oxide will be referred to as DSP (POE 20) Sodium Sulfate, etc. Rhodacal® DS-4, Abex® JKB, and Abex® EP-120 are registered trademarks of Rhodia corporation. Triton® X-405 is a registered trademark of Dow Corporation.
Example 1
[0026] 687.0 grams of deionized water, 33.0 grams of a 50 percent solution of DSP (POE 20) Sodium Sulfate, and 15.0 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced. Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 333.0 g methyl methacrylate, 333.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared. 67.0 g (10%) of the monomer mixture was charged to the reaction kettle. A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared, and 10% of the catalyst solution was then charged to the reaction kettle. A trace of ferrous sulfate was then added. The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours. During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes. The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle. After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag. The emulsion properties are shown in Table 1.
[0000]
TABLE 1
Emulsion
Properties
Solids
46.2
pH
8.7
Coagulum
<0.05%
Viscosity (centipoise)
430
Mean Particle Size (nm)
112.9
Polydispersity Index
0.124
Mechanical Stability
Good
Chemical Stability*
Good
*1M CaCl 2
Comparative Example 1
[0027] 687.0 grams of deionized water, 72.0 grams of a 22% solution of Sodium Doceylbenzene Sulfonate (Rhodacal® DS-4), and 18.7 grams of an 80% solution of Octylphenol (POE 40) (Triton® X-405) were added to the reaction kettle and agitation was commenced. Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 333.0 g methyl methacrylate, 333.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared. 67.0 g (10%) of the monomer mixture was charged to the reaction kettle. A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle. A trace of ferrous sulfate was then added. The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours. During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes. The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle. After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag. The emulsion properties are shown in Table 2.
[0000]
TABLE 2
Emulsion
Properties
Solids
46.0
pH
8.5
Coagulum
0.1%
Viscosity (centipoise)
55
Mean Particle Size (nm)
220.0
Polydispersity Index
0.309
Mechanical Stability
Good
Chemical Stability*
Poor
*1M CaCl 2
Example 2
[0028] 687.0 grams of deionized water, 72.0 grams of a 22% solution of Sodium Doceylbenzene Sulfonate (Rhodacal® DS-4), and 15.0 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced. Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 333.0 g methyl methacrylate, 333.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared. 67.0 g (10%) of the monomer mixture was charged to the reaction kettle. A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle. A trace of ferrous sulfate was then added. The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours. During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes. The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle. After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag. The emulsion properties are shown in Table 3.
[0000]
TABLE 3
Emulsion
Properties
Solids
46.0
pH
8.3
Coagulum
<0.1%
Viscosity (centipoise)
240
Mean Particle Size (nm)
105.0
Polydispersity Index
0.166
Mechanical Stability
Good
Chemical Stability*
Moderate
*1M CaCl 2
[0029] The properties of the emulsions in the above examples demonstrate the usefulness of the present invention. The combination of the Styrenated Phenol anionic and nonionic surfactants in example 1 yielded an emulsion with significantly lower particle size than the emulsion prepared from sodium doceylbenzene sulfonate and ethoxylated octylphenol in comparative example 1. Furthermore, the replacement of the standard nonionic surfactant, ethoxylated octylphenol, with DSP (POE 40) in example 2 yielded an emulsion with significantly lower particle size and particle size distribution.
Example 3
[0030] 687.0 grams of deionized water, 24.0 grams of a 50 percent solution of DSP (POE 20) Sodium Sulfate, and 7.9 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced. Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 288.0 g styrene, 210.0 g of ethyl acrylate and 26.0 g of methacrylic acid was prepared. 52.4 g (10%) of the monomer mixture was charged to the reaction kettle. A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle. A trace of ferrous sulfate was then added. The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of four hours. During the addition, the temperature of the reaction was maintained at 80° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 80° C. for an additional 30 minutes. The reaction mixture was then cooled to 40° C. and 8 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle. After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag. The emulsion properties are shown in Table 4.
[0000]
TABLE 4
Emulsion
Properties
Solids
39.0
pH
8.8
Coagulum
<0.2%
Viscosity (centipoise)
26
Mean Particle Size (nm)
108.8
Polydispersity Index
0.205
Mechanical Stability
Good
Chemical Stability*
Good
*1M CaCl 2
Comparative Example 2
[0031] 687.0 grams of deionized water, 40.0 grams of a 30% solution of C10-C12 fatty alcohol (POE 15) Ammonium Sulfate (Abex® JKB), and 9.8 grams of an 80% solution of Octylphenol (POE 40) (Triton® X-405) were added to the reaction kettle and agitation was commenced. Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 288.0 g styrene, 210.0 g of ethyl acrylate and 26.0 g of methacrylic acid was prepared. 52.4 g (10%) of the monomer mixture was charged to the reaction kettle. A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle. A trace of ferrous sulfate was then added. The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of four hours. During the addition, the temperature of the reaction was maintained at 80° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 80° C. for an additional 30 minutes. The reaction mixture was then cooled to 40° C. and 8 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle. After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag. The emulsion properties are shown in Table 5.
[0000]
TABLE 5
Emulsion
Properties
Solids
39.2
pH
8.6
Coagulum
<0.2%
Viscosity (centipoise)
14
Mean Particle Size (nm)
127.7
Polydispersity Index
0.254
Mechanical Stability
Good
Chemical Stability*
Good
*1M CaCl 2
Example 4
[0032] 687.0 grams of deionized water, 40.0 grams of a 30% solution of C10-C12 fatty alcohol (POE 15) Ammonium Sulfate (Abex® JKB), and 7.9 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced. Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 288.0 g styrene, 210.0 g of ethyl acrylate and 26.0 g of methacrylic acid was prepared. 52.4 g (10%) of the monomer mixture was charged to the reaction kettle. A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle. A trace of ferrous sulfate was then added. The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of four hours. During the addition, the temperature of the reaction was maintained at 80° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 80° C. for an additional 30 minutes. The reaction mixture was then cooled to 40° C. and 8 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle. After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag. The emulsion properties are shown in Table 6.
[0000]
TABLE 6
Emulsion
Properties
Solids
39.4
pH
8.7
Coagulum
<0.2%
Viscosity (centipoise)
20
Mean Particle Size (nm)
79.5
Polydispersity Index
0.094
Mechanical Stability
Good
Chemical Stability*
Good
*1M CaCl 2
[0033] The properties of the styrene acrylic emulsions in example 3 and example 4 again demonstrate the usefulness of the present invention. The Styrenated Phenol Ethoxylates yielded emulsions with smaller particle size compared to the emulsion synthesized using the conventional polymerization surfactants.
[0034] The following additional examples further illustrate the usefulness of the invention. The surfactants of the present invention again yielded emulsions with smaller particle size compared with the emulsion prepared using the conventional surfactant combination of Nonylphenol (POE 30) Ammonium Sulfate and Octylphenol (POE 40).
Example 5
[0035] 687.0 grams of deionized water, 50.0 grams of a 30% solution of DSP (POE 40) Ammonium Sulfate, and 15.0 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced. Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 134.4 g methyl methacrylate, 532.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared. 67.0 g (10%) of the monomer mixture was charged to the reaction kettle. A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle. A trace of ferrous sulfate was then added. The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours. During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes. The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle. After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag. The emulsion properties are shown in Table 7.
[0000]
TABLE 7
Emulsion
Properties
Solids
45.6
pH
8.5
Coagulum
<0.1%
Viscosity (centipoise)
140
Mean Particle Size (nm)
125.7
Polydispersity Index
0.032
Mechanical Stability
Good
Chemical Stability*
Good
*1M CaCl 2
Comparative Example 3
[0036] 687.0 grams of deionized water, 50.0 grams of a 30% solution of Nonylphenol (POE 30) Ammonium Sulfate (Abex® EP-120), and 18.7 grams of an 80% solution of Octylphenol (POE 40) (Triton® X-405) were added to the reaction kettle and agitation was commenced. Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 134.4 g methyl methacrylate, 532.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared. 67.0 g (10%) of the monomer mixture was charged to the reaction kettle. A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle. A trace of ferrous sulfate was then added. The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours. During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes. The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle. After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag. The emulsion properties are shown in Table 8.
[0000]
TABLE 8
Emulsion
Properties
Solids
45.6
pH
8.7
Coagulum
<0.1%
Viscosity (centipoise)
110
Mean Particle Size (nm)
131.2
Polydispersity Index
0.040
Mechanical Stability
Good
Chemical Stability*
Good
*1M CaCl 2
Example 6
[0037] 687.0 grams of deionized water, 50.0 grams of a 30% solution of Nonylphenol (POE 30) Ammonium Sulfate (Abex® EP-120), and 15.0 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced. Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 134.4 g methyl methacrylate, 532.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared. 67.0 g (10%) of the monomer mixture was charged to the reaction kettle. A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle. A trace of ferrous sulfate was then added. The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours. During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes. The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle. After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag. The emulsion properties are shown in Table 9.
[0000]
TABLE 9
Emulsion
Properties
Solids
45.3
pH
8.3
Coagulum
<0.1%
Viscosity (centipoise)
280
Mean Particle Size (nm)
116.4
Polydispersity Index
0.040
Mechanical Stability
Good
Chemical Stability*
Good
*1M CaCl 2
[0038] All patents, patent applications and publications cited in this application including all cited references in those applications, are hereby incorporated by reference in their entirety for all purposes to the same extent as if each individual patent, patent application or publication were so individually denoted.
[0039] While the many embodiments of the invention have been disclosed above and include presently preferred embodiments, many other embodiments and variations are possible within the scope of the present disclosure and in the appended claims that follow. Accordingly, the details of the preferred embodiments and examples provided are not to be construed as limiting. It is to be understood that the terms used herein are merely descriptive rather than limiting and that various changes, numerous equivalents may be made without departing from the spirit or scope of the claimed invention. | The present invention relates to the use of Styrenated Phenol Ethoxylates as surfactants in emulsion polymerization. The present invention further relates to the use of both anionic and nonionic Styrenated Phenol Ethoxylates in emulsion polymerization. Latexes with small average particle and narrow particle size distributions are obtained. Prepared latexes also have low coagulum levels and exhibit excellent mechanical and chemical stability. | Identify the most important claim in the given context and summarize it | [
"[0001] This application claims the priority benefit under 35 U.S.C. section 119 of U.S. Provisional Patent Application No. 60/935,402 entitled “Styrenated Phenol Ethoxylates In Emulsion Polymerization”, filed Aug. 10, 2007, which is in its entirety herein incorporated by reference.",
"FIELD OF THE INVENTION [0002] The present invention relates to emulsion polymerizing ethylenically unsaturated monomers monomers.",
"This invention also relates to emulsion polymerization of ethylenically unsaturated monomers by using styrenated surfactants as the primary emulsifier.",
"The instant invention also relates to a process for the preparation of a polymer dispersion by free radical polymerization of an aqueous monomer emulsion.",
"The present invention further relates to a method for production of waterborne polymer and copolymer dispersions comprising monomer units derived from at least one polymerizable ethylenically unsaturated monomers.",
"The polymer and copolymer dispersions are obtained in a free radical emulsion polymerization process performed in an aqueous media and in the presence of at least one styrenated surfactant.",
"In a further aspect the present invention refers to the use of said polymer or copolymer dispersion.",
"BACKGROUND OF THE INVENTION [0003] Emulsion polymerization is the most important industrial method for manufacture of aqueous dispersion polymers.",
"Emulsion polymerization is typically performed in an aqueous medium in the presence of a surfactant and a water soluble initiator and is usually rapidly producing high molecular weight homo or copolymers at high solids content and low dispersion viscosity.",
"Its application requires the emulsification of the monomer in a medium, usually water, through the use of emulsifiers.",
"These are supplied in addition to the other ingredients that go into most polymerizations, such as the initiator and chain transfer agents.",
"The use and type of emulsifier determines many of the characteristics of the produced polymer or copolymer, which is typically a latex (stable colloidal suspension of polymer particles in a continuous phase, usually water).",
"Moreover, the emulsifier usually cannot be completely removed from the latex.",
"For this reason, and because of the great unpredictability of the efficacy of a given surface-active agent as an emulsifier in polymerization, many compounds that would theoretically be useful are not.",
"[0004] It is also known that emulsion polymerization requires the use of a surfactant to form a stable emulsion of monomers and to prevent coagulation of the product polymer.",
"Surfactants are generally categorized into two types: either non-polymerizable, or polymerizable, that is co-polymerizable with the monomers for polymer formation.",
"A problem which has arisen with the use of non-polymerizable surfactants is that they remain as a residue in the product polymer and, as they can be extracted by water, they make the product sensitive to water.",
"Surfactants are also categorized as anionic, cationic, non-ionic or switterionic depending on their chemical makeup.",
"[0005] With the customary emulsion polymerization processes, suitable latices have been difficult to obtain since the latices usually contain particles of varying size and are either too fine or too large.",
"Various proposals have heretofore been made to overcome these difficulties but not with the ultimate success desired.",
"For example, the use of various different emulsifiers and catalysts have been proposed.",
"Also, varying the conditions of polymerization has been suggested.",
"However, in most of these cases, too much coagulation occurred with the resulting latex containing too much coagulum or partially agglomerated particles which precipitate reducing the yield.",
"Further, the shelf life of such latices leave much to be desired.",
"It is desirable to have latices which change very little during storage with respect to viscosity and have and maintain good heat stability.",
"[0006] The final product resulting from emulsion polymerization is normally an opaque, grey or milky-white dispersion of high molecular weight polymer(s) at a solids content of typically 30-60% in water.",
"Said dispersion typically comprises acrylic, methacrylic and crotonic acid homo and copolymers, methacrylate and acrylate ester homo or copolymers, vinyl acetate homo or copolymers, vinyl and vinylidene chloride homo or copolymers, ethylene homo or copolymers, styrene and butadiene homo or copolymers, acrylamide homo or copolymers, butadiene-acrylonitrile copolymers, styrene-acrolein copolymers and/or where applicable carboxylated versions.",
"Traditional applications for such aqueous dispersions are adhesives, binders for fibres and particulate matter, protective and decorative coatings, dipped goods, foam, paper coatings, backings for carpet and upholstery, modifiers for bitumens and concrete and thread and textile modifiers.",
"More recent applications include biomedical applications as protein immobilisers, visual detectors in immunoassays, as release agents, in electronic applications as photoresists for circuit boards, in batteries, conductive paint, copy machines and as key components in molecular electronic devices.",
"[0007] Ethoxylated Styrenated Phenols have been widely disclosed as effective and efficient pigment dispersants in a variety of applications.",
"U.S. Pat. No. 6,736,892 (2004) discloses anionic Styrenated Phenol Ethoxylates as pigment dispersants in water based ink and coating applications.",
"US application 0235877 A1 (2005) discloses fatty acid esters of Styrenated Phenol Alkoxylates as effective and efficient pigment dispersants for solvent based systems.",
"U.S. Pat. No. 5,035,785 (1991) discloses nonionic Styrenated Phenol Ethoxylates as effective and efficient pigment dispersants in electrodeposition baths.",
"The dispersants were also found to increase film build and dramatically improve film appearance and maintain the improved film appearance in this application.",
"Thus the utility of Styrenated Phenol Ethoxylates, both anionic and nonionic, in separating and stabilizing pigment particles against aggregation has been well known and demonstrated in both aqueous and non aqueous systems.",
"In these applications, these surfactants are added as part of the formulation comprising the resin used as a binder or film former, the pigment paste or dispersion, and other additives such as coalescing aids, viscosity modifiers, and other additives well know to those familiar with the art.",
"[0008] In emulsion polymerization of ethylenically unsaturated monomers, it is well known to those familiar with the art that surfactants are necessary and essential ingredients required for the polymerization reaction to occur in the aqueous phase.",
"It is also well know to those familiar with the art that surfactants further function by stabilizing the latex particles against aggregation from shear or mechanical force and also stabilize the latex particles from aggregation due to the addition of electrolyte to the latex.",
"In the emulsion polymerization process, since the radical polymerization takes place inside the surfactant formed micelles, the surfactants in emulsion polymerization are essential components in the manufacture of the latex.",
"(Bejamin B. Kline and George H. Redlich, “The Role of Surfactants in Emulsion Polymerization”, Surfactant Science Series, 26, 1988) It is also well know to those skilled in the art that the selection of surfactant type and level is also the determining factor in many emulsion properties, in particular the particle size of the latex particles.",
"Low particle size is highly desirable in pigmentation and results in higher gloss in the final film or coating.",
"[0009] We have now found that the Styrenated Phenol Ethoxylates are useful as surfactants in the emulsion polymerization of ethylenically unsaturated monomers.",
"The use of both anionic and nonionic Styrenated Phenol Ethoxylates in the emulsion polymerization process provides latexes with small particle size and small particle size distributions.",
"Furthermore, latexes prepared using Styrenated Phenol Ethoxylates have excellent mechanical and chemical stability.",
"The Styrenated Phenol Ethoxylates of the present invention may also be used in combination with conventional surfactants to improve latex properties.",
"SUMMARY OF THE INVENTION [0010] The present invention provides a process for the emulsion polymerization of at least one ethylenically unsaturated monomer containing at least one carbon-to-carbon double bond, said process comprising polymerizing said ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble initiator and a surfactant of the formula: [0000] [0000] wherein n=1, 2 or 3;",
"X is 1-100;",
"Z is selected from the group consisting of SO 3 − or PO 3 2− ;",
"and M + is selected from the group consisting of Na + , K + , NH 4 + , and an alkanolamine.",
"[0011] The present invention also provides a process for the emulsion polymerization of at least one ethylenically unsaturated monomer containing at least one carbon-to-carbon double bond, said process comprising polymerizing said ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble initiator and a surfactant of the formula: [0000] [0000] wherein n=1, 2, 3;",
"x is preferably 1-100.",
"[0012] The instant invention further provides a process for the emulsion polymerization of at least one ethylenically unsaturated monomer containing at least one carbon-to-carbon double bond, said process comprising polymerizing said ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble initiator and a mixture of surfactants of the formula I and II: [0000] [0000] wherein n=1, 2, 3;",
"x is preferably 1-100;",
"Z can be either SO 3 − or PO 3 2− , and M + is Na + , K + , NH 4 + , or an alkanolamine.",
"DETAILED DESCRIPTION OF THE INVENTION [0013] The present invention is directed towards the emulsion polymerization of ethylenically unsaturated monomers in the presence of a anionic surfactant of formula (I) [0000] [0000] where n=1, 2, 3;",
"x is preferably 1-100, more preferably from about 5 to 60, and most preferably from about 5 to 40;",
"Z can be either SO 3 − or PO 3 2− , and M + is Na + , K + , NH 4 + , or an alkanolamine.",
"[0014] The present invention is further directed towards the emulsion polymerization of ethylenically unsaturated monomers in the presence of a nonionic surfactant of formula (II) [0000] [0000] where n=1, 2, 3;",
"X is preferably 1-100.",
"more preferably from about 5 to 60, and most preferably from about 5 to 40.",
"[0015] The compounds of formulas (I) and (II) may be used separately or in combination in the emulsion polymerization.",
"More commonly they are used in combination.",
"When used in combination, the ratio of compounds of formula (I) to compounds of formula (II) is not limited but is dictated by the desired emulsion properties.",
"Surfactants of formulas (I) and (II) may also be used in combination with other surfactants that are commonly used in the art When used in combination, the ratio of surfactants is not specific but is commonly optimized based on the nature of the ethylenically unsaturated monomers present in a given formulation.",
"The total amount of surfactants of formulas (I) and formula (I) that may be used in the present invention is preferably from about 0.1% to about 20% based on total weight of the monomer, more preferably from about 0.2% to about 10%, and most preferably from about 0.5% to about 7% based on the total weight of the monomer.",
"The compounds of formulas (I) and (II) may also be used in combination with conventional surfactants in order to improve emulsion properties [0016] Surfactants that are commonly used in the emulsion polymerization process include both anionic and nonionic molecules.",
"Commonly utilized anionic surfactants in the emulsion polymerization process include sodium alkylbenzene sulfonates, alkyldiphenyloxide disulfonates, ethoxylated alkylphenol sulfates and phosphates, alkyl sulfosuccinates, and sulfates and phosphates of fatty alcohols, etc.",
"Commonly utilized nonionic surfactants include linear and branched alcohol ethoxylates, and alkylphenol ethoxylates, particularly octylphenol ethoxylates.",
"When used in combination with other surfactants the ratios are not limited but are also dictated by the desired emulsion properties.",
"[0017] Suitable monomers that may be polymerized by the practice of the present invention include numerous ethylenically unsaturated monomers such as vinyl monomers or acrylic monomers.",
"Typical vinyl monomers suitable for use in accordance with the present invention include, but are not limited to, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, etc;",
"vinyl aromatic hydrocarbons such as styrene, methyl styrenes, other vinyl aromatics such as vinyl toluenes, vinyl napthalenes, divinyl benzene, etc.",
"Halogenated vinyl monomers such as vinyl chloride, vinylidene chloride, etc.",
"may also be used.",
"[0018] Suitable acrylic monomers which may be used in accordance with the present invention comprise compounds with acrylic functionality such as alkyl acrylates and methacrylates, acrylate acids and methacrylate acids as well as acrylamides and acrylonitrile.",
"Typical acrylic monomers include, but are not limited to methyl acrylate and methyl methacrylate, ethyl, propyl, and butyl acrylate and methacrylate, benzyl acrylate and methacrylate, cyclohexyl acrylate and methacrylate, decyl and dodecyl acrylate and methacrylate, etc.",
"Other typical acrylic monomers include hydroxy alkyl acrylates and methacrylates such as hydroxypropyl and hydroxyethyl acrylate and methacrylate, acrylic acids such as methacrylic and acrylic acid, and amino acrylates and methacrylates.",
"It will be recognized by those familiar with the art that other unsaturated monomers which are suitable for free radical addition polymerization may also be used in accordance with the present invention.",
"[0019] Numerous free radical forming compounds are utilized as catalysts in the emulsion polymerization process.",
"Typically compounds used as catalysts are those that from free radicals via thermal decomposition, referred to in the art as “thermal initiators”",
"or combinations of compounds that form free radicals via oxidation/reduction reactions.",
"Such catalysts are combinations of an oxidizing agent and a reducing agent and are commonly referred to in the art as “redox initiators.”",
"Either thermal or redox catalysts may be used in the practice of the present invention.",
"[0020] Typical catalysts utilized as thermal initiators include persulfates, specifically potassium persulfate, sodium persulfate, ammonium persulfate and the like.",
"Typical redox initiators include combinations of oxidizing agents or initiators such as peroxides, specifically benzoyl peroxide, t-butyl hydroperoxide, lauryl peroxide, hydrogen peroxide, 2,2′-diazobisisobutyronitrile, and the like.",
"Typical reducing agents include sodium bisulfite, sodium formaldehyde sulfoxylate, sodium hydrosulfite, and ascorbic and isoascorbic acid.",
"The catalyst or initiator is employed in an amount preferably from 0.1 to 3 weight percent of the total monomer weight, and most preferably from about 0.1 to 1 weight percent of the total monomer charge.",
"[0021] Other additives or components which are known to those skilled in the art may also used in accordance with the present invention.",
"These include chain transfer agents, which are used to control molecular weight, additives to adjust pH, and compounds utilized as protective colloids which provide additional stability to the latex particles.",
"[0022] Any of the conventional methods employed in the emulsion polymerization process may also be used in accordance with the present invention.",
"These include both standard and pre-emulsion monomer addition techniques as well as staged monomer addition.",
"EXAMPLES [0023] The following examples and comparative examples are intended to illustrate the usefulness of the invention and are not to be construed as limiting or defining the entire scope of the invention in any way.",
"[0024] All reactions were carried out in a 1500 mL glass reactor equipped with a four-blade stainless steel agitator, nitrogen gas inlet, thermocouple connected to a digital temperature controller, reflux condenser, and inlets for the addition of monomer mixture and catalyst solutions.",
"Emulsion viscosities were measured using a Brookfield LVT Viscometer using a # 2 spindle at 30 rpm.",
"Particle size measurements were run on a Brookhaven 90Plus Particle Size Analyzer.",
"[0025] The Styrenated Phenol Ethoxylates of the present invention will be referred to in an abbreviated fashion.",
"For example, the Sodium Sulfate salt of Distyrenated Phenol containing 20 moles of ethylene oxide will be referred to as DSP (POE 20) Sodium Sulfate, etc.",
"Rhodacal® DS-4, Abex® JKB, and Abex® EP-120 are registered trademarks of Rhodia corporation.",
"Triton® X-405 is a registered trademark of Dow Corporation.",
"Example 1 [0026] 687.0 grams of deionized water, 33.0 grams of a 50 percent solution of DSP (POE 20) Sodium Sulfate, and 15.0 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced.",
"Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 333.0 g methyl methacrylate, 333.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared.",
"67.0 g (10%) of the monomer mixture was charged to the reaction kettle.",
"A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared, and 10% of the catalyst solution was then charged to the reaction kettle.",
"A trace of ferrous sulfate was then added.",
"The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours.",
"During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes.",
"The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle.",
"After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag.",
"The emulsion properties are shown in Table 1.",
"[0000] TABLE 1 Emulsion Properties Solids 46.2 pH 8.7 Coagulum <0.05% Viscosity (centipoise) 430 Mean Particle Size (nm) 112.9 Polydispersity Index 0.124 Mechanical Stability Good Chemical Stability* Good *1M CaCl 2 Comparative Example 1 [0027] 687.0 grams of deionized water, 72.0 grams of a 22% solution of Sodium Doceylbenzene Sulfonate (Rhodacal® DS-4), and 18.7 grams of an 80% solution of Octylphenol (POE 40) (Triton® X-405) were added to the reaction kettle and agitation was commenced.",
"Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 333.0 g methyl methacrylate, 333.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared.",
"67.0 g (10%) of the monomer mixture was charged to the reaction kettle.",
"A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle.",
"A trace of ferrous sulfate was then added.",
"The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours.",
"During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes.",
"The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle.",
"After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag.",
"The emulsion properties are shown in Table 2.",
"[0000] TABLE 2 Emulsion Properties Solids 46.0 pH 8.5 Coagulum 0.1% Viscosity (centipoise) 55 Mean Particle Size (nm) 220.0 Polydispersity Index 0.309 Mechanical Stability Good Chemical Stability* Poor *1M CaCl 2 Example 2 [0028] 687.0 grams of deionized water, 72.0 grams of a 22% solution of Sodium Doceylbenzene Sulfonate (Rhodacal® DS-4), and 15.0 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced.",
"Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 333.0 g methyl methacrylate, 333.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared.",
"67.0 g (10%) of the monomer mixture was charged to the reaction kettle.",
"A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle.",
"A trace of ferrous sulfate was then added.",
"The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours.",
"During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes.",
"The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle.",
"After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag.",
"The emulsion properties are shown in Table 3.",
"[0000] TABLE 3 Emulsion Properties Solids 46.0 pH 8.3 Coagulum <0.1% Viscosity (centipoise) 240 Mean Particle Size (nm) 105.0 Polydispersity Index 0.166 Mechanical Stability Good Chemical Stability* Moderate *1M CaCl 2 [0029] The properties of the emulsions in the above examples demonstrate the usefulness of the present invention.",
"The combination of the Styrenated Phenol anionic and nonionic surfactants in example 1 yielded an emulsion with significantly lower particle size than the emulsion prepared from sodium doceylbenzene sulfonate and ethoxylated octylphenol in comparative example 1.",
"Furthermore, the replacement of the standard nonionic surfactant, ethoxylated octylphenol, with DSP (POE 40) in example 2 yielded an emulsion with significantly lower particle size and particle size distribution.",
"Example 3 [0030] 687.0 grams of deionized water, 24.0 grams of a 50 percent solution of DSP (POE 20) Sodium Sulfate, and 7.9 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced.",
"Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 288.0 g styrene, 210.0 g of ethyl acrylate and 26.0 g of methacrylic acid was prepared.",
"52.4 g (10%) of the monomer mixture was charged to the reaction kettle.",
"A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle.",
"A trace of ferrous sulfate was then added.",
"The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of four hours.",
"During the addition, the temperature of the reaction was maintained at 80° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 80° C. for an additional 30 minutes.",
"The reaction mixture was then cooled to 40° C. and 8 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle.",
"After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag.",
"The emulsion properties are shown in Table 4.",
"[0000] TABLE 4 Emulsion Properties Solids 39.0 pH 8.8 Coagulum <0.2% Viscosity (centipoise) 26 Mean Particle Size (nm) 108.8 Polydispersity Index 0.205 Mechanical Stability Good Chemical Stability* Good *1M CaCl 2 Comparative Example 2 [0031] 687.0 grams of deionized water, 40.0 grams of a 30% solution of C10-C12 fatty alcohol (POE 15) Ammonium Sulfate (Abex® JKB), and 9.8 grams of an 80% solution of Octylphenol (POE 40) (Triton® X-405) were added to the reaction kettle and agitation was commenced.",
"Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 288.0 g styrene, 210.0 g of ethyl acrylate and 26.0 g of methacrylic acid was prepared.",
"52.4 g (10%) of the monomer mixture was charged to the reaction kettle.",
"A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle.",
"A trace of ferrous sulfate was then added.",
"The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of four hours.",
"During the addition, the temperature of the reaction was maintained at 80° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 80° C. for an additional 30 minutes.",
"The reaction mixture was then cooled to 40° C. and 8 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle.",
"After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag.",
"The emulsion properties are shown in Table 5.",
"[0000] TABLE 5 Emulsion Properties Solids 39.2 pH 8.6 Coagulum <0.2% Viscosity (centipoise) 14 Mean Particle Size (nm) 127.7 Polydispersity Index 0.254 Mechanical Stability Good Chemical Stability* Good *1M CaCl 2 Example 4 [0032] 687.0 grams of deionized water, 40.0 grams of a 30% solution of C10-C12 fatty alcohol (POE 15) Ammonium Sulfate (Abex® JKB), and 7.9 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced.",
"Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 288.0 g styrene, 210.0 g of ethyl acrylate and 26.0 g of methacrylic acid was prepared.",
"52.4 g (10%) of the monomer mixture was charged to the reaction kettle.",
"A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle.",
"A trace of ferrous sulfate was then added.",
"The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of four hours.",
"During the addition, the temperature of the reaction was maintained at 80° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 80° C. for an additional 30 minutes.",
"The reaction mixture was then cooled to 40° C. and 8 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle.",
"After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag.",
"The emulsion properties are shown in Table 6.",
"[0000] TABLE 6 Emulsion Properties Solids 39.4 pH 8.7 Coagulum <0.2% Viscosity (centipoise) 20 Mean Particle Size (nm) 79.5 Polydispersity Index 0.094 Mechanical Stability Good Chemical Stability* Good *1M CaCl 2 [0033] The properties of the styrene acrylic emulsions in example 3 and example 4 again demonstrate the usefulness of the present invention.",
"The Styrenated Phenol Ethoxylates yielded emulsions with smaller particle size compared to the emulsion synthesized using the conventional polymerization surfactants.",
"[0034] The following additional examples further illustrate the usefulness of the invention.",
"The surfactants of the present invention again yielded emulsions with smaller particle size compared with the emulsion prepared using the conventional surfactant combination of Nonylphenol (POE 30) Ammonium Sulfate and Octylphenol (POE 40).",
"Example 5 [0035] 687.0 grams of deionized water, 50.0 grams of a 30% solution of DSP (POE 40) Ammonium Sulfate, and 15.0 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced.",
"Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 134.4 g methyl methacrylate, 532.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared.",
"67.0 g (10%) of the monomer mixture was charged to the reaction kettle.",
"A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle.",
"A trace of ferrous sulfate was then added.",
"The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours.",
"During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes.",
"The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle.",
"After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag.",
"The emulsion properties are shown in Table 7.",
"[0000] TABLE 7 Emulsion Properties Solids 45.6 pH 8.5 Coagulum <0.1% Viscosity (centipoise) 140 Mean Particle Size (nm) 125.7 Polydispersity Index 0.032 Mechanical Stability Good Chemical Stability* Good *1M CaCl 2 Comparative Example 3 [0036] 687.0 grams of deionized water, 50.0 grams of a 30% solution of Nonylphenol (POE 30) Ammonium Sulfate (Abex® EP-120), and 18.7 grams of an 80% solution of Octylphenol (POE 40) (Triton® X-405) were added to the reaction kettle and agitation was commenced.",
"Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 134.4 g methyl methacrylate, 532.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared.",
"67.0 g (10%) of the monomer mixture was charged to the reaction kettle.",
"A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle.",
"A trace of ferrous sulfate was then added.",
"The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours.",
"During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes.",
"The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle.",
"After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag.",
"The emulsion properties are shown in Table 8.",
"[0000] TABLE 8 Emulsion Properties Solids 45.6 pH 8.7 Coagulum <0.1% Viscosity (centipoise) 110 Mean Particle Size (nm) 131.2 Polydispersity Index 0.040 Mechanical Stability Good Chemical Stability* Good *1M CaCl 2 Example 6 [0037] 687.0 grams of deionized water, 50.0 grams of a 30% solution of Nonylphenol (POE 30) Ammonium Sulfate (Abex® EP-120), and 15.0 grams of DSP (POE 40) were added to the reaction kettle and agitation was commenced.",
"Oxygen was removed from the solution by nitrogen sparge and the solution was heated to 65° C. Next a monomer mixture of 134.4 g methyl methacrylate, 532.0 g of butyl acrylate and 6.0 g of methacrylic acid was prepared.",
"67.0 g (10%) of the monomer mixture was charged to the reaction kettle.",
"A catalyst solution consisting of 5.0 g potassium persulfate in 100.0 g deionized water was then prepared and 10% of the catalyst solution was then charged to the reaction kettle.",
"A trace of ferrous sulfate was then added.",
"The reaction mixture exothermed to 70-75° C. The remaining monomer mixture and catalyst solution were then metered in to the reaction kettle over a period of two hours.",
"During the addition, the temperature of the reaction was maintained between 70-75° C. After the addition of monomer and catalyst was complete, the reaction mixture was held at 70-75° C. for an additional 30 minutes.",
"The reaction mixture was then cooled to 40° C. and 4 grams of ammonium hydroxide in 20 mL deionized water was added slowly to the reaction kettle.",
"After stirring for an additional 15 minutes, the emulsion was filtered through a 150 micron filter bag.",
"The emulsion properties are shown in Table 9.",
"[0000] TABLE 9 Emulsion Properties Solids 45.3 pH 8.3 Coagulum <0.1% Viscosity (centipoise) 280 Mean Particle Size (nm) 116.4 Polydispersity Index 0.040 Mechanical Stability Good Chemical Stability* Good *1M CaCl 2 [0038] All patents, patent applications and publications cited in this application including all cited references in those applications, are hereby incorporated by reference in their entirety for all purposes to the same extent as if each individual patent, patent application or publication were so individually denoted.",
"[0039] While the many embodiments of the invention have been disclosed above and include presently preferred embodiments, many other embodiments and variations are possible within the scope of the present disclosure and in the appended claims that follow.",
"Accordingly, the details of the preferred embodiments and examples provided are not to be construed as limiting.",
"It is to be understood that the terms used herein are merely descriptive rather than limiting and that various changes, numerous equivalents may be made without departing from the spirit or scope of the claimed invention."
] |
FIELD OF INVENTION
The present invention relates to an arrangement having at least one movable furniture part, in particular having a drawer or the like, having at least one drive unit and at least one regulating device for regulating the at least one drive unit.
DESCRIPTION OF RELATED ART
Arrangements of this kind are in principle already known. For example, U.S. Pat. No. 5,158,347 describes an item of office furniture in which the drawers are moved by a motor over a first region of the entire opening distance once an identification code has been input. EP 0 957 225 describes an opening means for a closure element, for example a drawer, that is triggered by way of a capacitor that discharges electrically when touched by the user. Here too, the drawer is only moved partly out of the furniture carcass. German patent specification DE 10 17 351 describes a device for pulling drawers out of or pushing them into items of furniture, which may be triggered by push buttons arranged on the carcass. In this case, by using the push buttons, any possible position for the drawer along the entire opening distance is possible. In this case, it is problematic that such opening aids always have to be triggered by way of actuating elements provided specifically therefor, which many users find awkward. Particularly for those people who are skeptical about technology in general, it would be advantageous if it were possible to operate driven movable furniture parts in the good old-fashioned way, by pushing or pulling on the drawer.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a generic arrangement that makes it possible to operate intuitively a movable furniture part that is driven by a drive unit.
This object is achieved in accordance with the invention in that the arrangement has at least one, preferably analog, acceleration measuring device, with the at least one acceleration measuring device generating an acceleration signal that is characteristic of accelerations caused by forces applied to the at least one movable furniture part from the outside and that may be supplied to the at least one regulating device.
It is technically advantageous herein that in the arrangement according to the invention there are no longer any actuating elements of any kind provided to trigger the drive unit for the movable furniture parts. It is economically advantageous herein that a greater level of acceptance on the market is to be expected for the arrangement according to the invention.
It is not significant whether the acceleration is measured directly or calculated from other measured variables. In this sense, a device for determining the position of the movable furniture part combined with a clock also forms an acceleration measuring device. In this case, the speed can be determined from the distance covered in a given time span, and the acceleration can be determined from the change in speed.
According to the invention, however, recognition of the fact that an acceleration of the movable furniture part has taken place is already sufficient, regardless of the magnitude or direction of the acceleration.
Advantageously, in one embodiment of the invention it is provided for the at least one drive unit to include an electric motor. Extremely small electric motors of this kind are commercially available and guarantee problem-free operation with a low current consumption.
A particularly advantageous embodiment of the invention results when the acceleration signal contains information on the magnitude and/or direction, preferably the directional component parallel to the direction of pulling out the movable furniture part, of the acceleration caused by forces applied to the movable furniture part from the outside. This allows the acceleration measuring device to make information available to the regulating device about the direction in which actuation of the draw should be performed. If the regulating device receives, for example, from the acceleration measuring device the signal of a pulling acceleration being present, it can immediately send the drive unit a control command to move the movable furniture part in the direction of the measured pulling acceleration. In this case, which opening condition the draw is in at the time of external actuation has no significance per se. Advantageously, however, it is provided that, in a certain region before the opened and closed end positions of the movable furniture part, there is no longer a driven movement of the furniture part, in order to prevent damage to the furniture part or the arrangement according to the invention. For this purpose, it is advantageous for the arrangement to have at least one position measuring device that generates a position signal that is characteristic of the opening condition of the movable furniture part and may be supplied to the regulating device. In this way, the regulating device can recognize at any time whether the movable furniture part is in the vicinity of one of the end positions.
Advantageously, the acceleration signal emitted by the acceleration measuring device to the regulating device also contains information on the magnitude of the acceleration of the movable furniture part that the user exerts on it. It is possible for example to conclude from an acceleration of large magnitude that rapid opening or closing is desired, as a result of which the regulating device can actuate the drive unit in a manner corresponding to the situation.
An advantageous embodiment of the invention results when the drive unit accelerates the movable furniture part approximately evenly over a predetermined time span. Because the acceleration of the movable furniture part is performed only over a predetermined time span, the illusion for the user that the furniture part is not driven is maintained. Once the time span has expired, the movable furniture part is braked by the friction inherent in the system just as though no drive unit were present. However, it would also be possible to provide for a lower acceleration to be maintained after the time span of acceleration, in order to compensate the braking caused by the friction. This maintains the impression of a non-driven furniture part that is, for example, mounted in a manner with particularly low friction. Alternatively, or in addition, it may also be provided for the drive unit to accelerate the movable furniture part only over a predeterminable or predetermined partial distance whereof the length is shorter than the length of the total distance between the closed end position and the opened end position of the movable furniture part. Because the drive unit is not active over the entire opening distance, the sought invisibility of the technology is maintained.
It may also be provided for the movement of the movable furniture part by the drive unit to be independent of the magnitude of the pulling or pushing acceleration. As a result of this, the user is the only one to decide, through the magnitude of force he or she applies, how fast the movement of the movable furniture part is to be, with the drive unit always providing the same supporting acceleration.
A particularly advantageous embodiment of the invention results when the regulating device has an actual-value calculating device that calculates, from the position signal generated by the position measuring device, the current actual position and/or the current actual speed of the movable furniture part. As a result of knowing the current position and speed of the movable furniture part, it is possible for the drive unit to perform an acceleration over defined partial distances, for example in the vicinity of the end positions of the movable furniture part, in such a way that the movable furniture part comes to a standstill in the respective end position.
In a further advantageous embodiment of the invention, it is provided for the arrangement to include at least one initialization device that generates a signal that is characteristic of certain predetermined positions of the movable furniture part in each case and may be supplied at least to the position measuring device. If the arrangement according to the invention is not equipped with expensive non-erasable electronic memory elements, then once the arrangement according to the invention has been disconnected from the voltage source, for example, the position of the movable furniture part in relation to the arrangement according to the invention must be established. Because the arrangement according to the invention is moreover commercially available in variously sized formats, the length of the total distance between the closed and the opened end positions of the movable furniture part and the positions of the movable furniture part in the closed and opened end positions must be established, at least on first start-up. This can be done for example by the user triggering the initialization device by way of an actuating element that is readily accessible from outside the arrangement, for example a button. With an initialization procedure of this kind, it may for example be provided for the user to move the movable furniture part into the closed end position, to actuate the actuating element there and then to move the movable furniture part into the opened end position and to actuate the actuating element again. The result of this is that the information required about the total length of the movement of the movable furniture part and about the position of the movable furniture part in the particular positions is available to the regulating device.
Alternatively, or in addition, initialization by a collision recognition would also be possible. In this case, the movable furniture part would travel slowly in the direction of one of the two end positions and, on reaching this, automatically trigger the initialization device as a result of the detected collision. For example, the drive unit could first move the movable furniture part in the direction of the closed end position and, when the front panel collided with the front side of the arrangement, the zero position could be automatically established by the initialization device. After that the drive unit could move the movable furniture part in the direction of the opened end position and, on collision, this position could be automatically established by the initialization device. The collision itself could for example be detected by a sudden rise in the current supplied to the drive unit, with the rise being attributable to those forces occurring between the movable furniture part and the arrangement that the drive unit attempts to overcome. It goes without saying that if a certain level of current were exceeded, it would cause the drive unit to be switched off in order to prevent damage. It would also be possible to trigger the initialization device if the magnitude of the speed of the movable furniture part over a predetermined time span were less than or equal to a predetermined limit value, for example zero.
With a touch-latch construction, the closed end position established by the initialization device would of course not be the position of the movable furniture part on collision, but a position lying further out by a predetermined distance. This would ensure the gap required for the touch-latch triggering between the front side of the arrangement and the front panel of the movable furniture part in the closed end position.
In a further advantageous embodiment of the invention, it is provided for the initialization device to be capable of being triggered by way of an actuating element that is arranged within the arrangement and is actuable by the movable furniture part. This removes the need for the user to actuate a special actuating element. An actuating element of this kind, arranged within the arrangement, may for example be constructed as a limit switch for determining the closed end position of the movable furniture part. For example, it may be provided for this limit switch to be constructed as a pressure switch. When the movable furniture part is pushed in, either by way of the drive unit or by the user, the limit switch is actuated by the movable furniture part over the last few millimeters of the distance of pushing in. As a result, the closed end position of the movable furniture part in the arrangement according to the invention is established. It may also be provided for the limit switch or the actuating element to be constructed in general as an inductive or capacitive sensor, with the result that the respective end positions of the movable furniture part may be detected without making contact. Other types of sensor known to those skilled in the art may also be provided.
It is also conceivable for the initialization device to be capable of being triggered by making a conductive connection between the arrangement and a voltage source by way of a triggering element. As a result, initialization takes place automatically on first start-up or when the voltage supply is re-established after a power failure.
It goes without saying that it is also possible to provide for two more constructions of the above-mentioned types of actuation of the initialization device to be combined in an arrangement according to the invention. It goes without saying that triggering of the initialization device may also be performed by its being manually pulled out. In this case, the movable furniture part is moved manually by a user, for example out of the closed end position into the fully opened end position.
In a further advantageous embodiment of the invention, it is provided for the movable furniture part to be mounted movably on frames arranged laterally within the arrangement. Frames of this kind, which are per se part of the prior art, allow a low-friction and secure mounting of the movable furniture part in the arrangement according to the invention.
In a further advantageous embodiment of the invention, it is provided for the drive unit to be attached to a frame. This may for example make a separate drive unit available for each movable furniture part. It may also be possible to attach frames to which drive units are secured in an arrangement according to the invention from the outset.
In a further advantageous embodiment of the invention, it is provided for the drive unit to be attached to the inner face of the arrangement opposite the rear wall of the movable furniture part, preferably at approximately the same spacing from the two side walls of the arrangement. This allows the movable furniture part to be accelerated largely without tilting when the drive unit is arranged centrally.
In a further advantageous embodiment of the invention, it is provided for the drive unit to be in constant connection with the movable furniture part. This makes it possible for the movable furniture part to be accelerated by the drive unit, regardless of the current position of the movable furniture part in relation to the arrangement according to the invention. For this, it is useful if for example the drive unit is in constant connection with the movable furniture part by way of at least one cable or a belt, preferably a toothed belt, or by way of a toothed wheel engaging in a toothed rack. The use of a toothed belt in this case guarantees a slip-free connection between the movable furniture part and the drive unit. Force may be exerted for example by the belt running over at least two rollers that are arranged on a lateral frame. It goes without saying that it is also possible for both lateral frames to be constructed to have at least two rollers, over which a respective belt is guided for the transmission of forces. It also goes without saying that the use of a cable without slip would be possible if both cable ends were fixed to the driven roller and so the one cable end were unwound and the other cable end wound up at the same time.
Above a certain width of the movable furniture part, it is advantageous if at least two rollers arranged on different frames are in a—preferably rigid—connection with one another by way of a connection shaft, and so may be moved by the drive unit.
A further advantageous embodiment of the invention results from at least one roller on at least one frame being drivable by the drive unit. This enables forces to be transmitted with lower losses than would be achievable if transmission devices were interposed between the drive unit and the movable furniture part.
In order to achieve more advantageous transmission of the movement of the drive unit to the movable furniture part, it may be provided for the at least one roller on at least one frame to be drivable by the drive unit by way of a gear. With a wide movable furniture part, it is again useful if gears are provided at both ends of the connection shaft. With very wide movable furniture parts, it may also be provided for drive units to be arranged on both sides of the movable furniture part, these drive units either having their own regulating devices and a synchronization means, or being capable of being controlled by a common regulating device.
In a further advantageous embodiment of the invention, it may be provided for the arrangement to include a resolver for measuring the position and/or speed and/or acceleration of the movable furniture part, whereof the signals may be supplied to the regulating device. Resolvers of this kind are commercially available and are extremely robust both mechanically and thermally. A resolver of this kind is constructed in accordance with the principle of a rotary transformer. Commercially available resolvers are frequently available with an integrated evaluation circuit, with the result that the signal thereof can be supplied directly to the regulating device.
In a further advantageous embodiment of the invention, it may be provided for the arrangement to include an optical encoder for measuring the position and/or speed and/or acceleration of the movable furniture part, whereof the signals may be supplied to the regulating device. Optical or indeed magnetic encoders of this kind represent a low-cost and frequently also space-saving alternative to resolvers. At the same time, they still guarantee a satisfactory angular range of triggering for an arrangement according to the invention, for example from 64 to 1024 pulses/revolution. Certain disadvantages with optical and magnetic encoders are produced from their sensitivity to mechanical vibration, soiling and the lack of absolute angle information at the time of switching on, with the result that encoders of this kind can only determine positions incrementally.
In a further advantageous embodiment of the invention, it is provided for the drive unit to include a brushless d.c. motor and for measurement of the position and/or speed and/or acceleration of the movable furniture part to be made directly by way of the commutator signal, with it being possible to supply the signals obtained in this way to the regulating device. Frequently, brushless motors of this kind are commercially available with a Hall-effect sensor construction.
Nowadays, extremely small electric motors are already available in which an electronic, optical or magnetic position measuring device is already integrated in the electric motor, which saves both space and time on installation.
The present invention furthermore relates to a process for moving a movable furniture part, in particular a draw, that is mounted in or on an arrangement, by a drive unit, in particular an electric motor, with the arrangement having a drive unit regulator and a position measuring device, wherein the position measuring device sends the drive unit regulator signals and the drive unit regulator gives the drive unit the command for accelerating the movable furniture part in dependence on these signals.
The position measuring device in this case represents a particularly simple way of realizing the acceleration measuring device, as already mentioned.
For example, it may be provided, in the event of a change in the movement condition of the movable furniture part that is caused from the outside, for the position measuring device to send a signal to the drive unit regulator and for the latter to give the drive unit the command for accelerating the movable furniture part. It goes without saying that a change in the movement condition should be understood—as is customary in physics—to include both starting up of the movable furniture part and a change in the speed of a movable furniture part performing an even movement.
However, it may also be provided, once the movable furniture part has moved over a predeterminable or predetermined distance, for the position measuring device to send a signal to the drive unit regulator and for the latter to give the drive unit the command for accelerating the movable furniture part. This case is thus purely a matter of distance measurement. The drive unit is activated as soon as the movable furniture part has covered the predetermined distance. The time required therefor has no effect.
With this triggering process, advantageously it may furthermore advantageously be provided for the distance to be covered by the movable furniture part, in accordance with which the position measuring device emits a signal to the drive unit regulator, to be adjustable or adjusted differently depending on the direction of movement of the movable furniture part. For example, a distance of 1 millimeter could be selected as the activation distance for triggering a movement directed away from the furniture carcass, whereas triggering of a movement directed toward the furniture carcass takes place after a distance of 10 millimeters.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages and details of the arrangement according to the invention will become apparent from the figures below and from the associated description of the figures, in which:
FIGS. 1 a and 1 b show an arrangement according to the invention, partly in cross-section, with the movable furniture part in the closed end position and in the triggered condition,
FIGS. 2 a and 2 b show an arrangement according to the invention, partly in cross-section, with the movable furniture part in the opened end position and in an intermediate position,
FIGS. 3 a , 3 b and 3 c show a variant on an arrangement according to the invention, partly in cross-section, with the movable furniture part in the closed end position, an associated detail view, and with the movable furniture part in the triggered condition,
FIGS. 4 a , 4 b and 4 c show an example embodiment of an arrangement according to the invention, partly in cross-section, with the movable furniture part in the closed end position, a detail view thereof, and with the movable furniture part in the triggered condition,
FIGS. 5 a and 5 b show a perspective view of components of an arrangement according to the invention and a detail view,
FIG. 6 shows a further perspective view of components of an example embodiment of an arrangement according to the invention,
FIGS. 7 a and 7 b show a further perspective view of an example embodiment of an arrangement according to the invention, and a detail view,
FIGS. 8 a and 8 b show the same subject as FIGS. 7 a and 7 b from a different angle of view,
FIG. 9 shows a perspective view of an example embodiment of an arrangement according to the invention,
FIG. 10 shows a perspective view of a further example embodiment of an arrangement according to the invention,
FIGS. 11 a and 11 b show perspective views of a further example embodiment of an arrangement according to the invention, with a movable furniture part in the opened end position, and a detail view,
FIGS. 12 a , 12 b , 12 c and 12 d show diagrammatic illustrations of components of an arrangement according to the invention,
FIGS. 13 a , 13 b and 13 c show distance/time graphs that describe by way of example the actuation of an arrangement according to the invention,
FIG. 14 shows a diagrammatic illustration of the flow of information between individual diagrammatically illustrated logical components of the arrangement according to the invention, and
FIGS. 15 a and 15 b show a diagrammatic illustration of an arrangement according to the invention, from different angles of view.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Visible in FIG. 1 a is a movable furniture part 3 , constructed as a drawer, in a view toward one of its side faces 12 . It can be seen that the drawer is constructed with a handle 28 . The movable furniture part 3 is mounted such that it is linearly movable in an arrangement 7 according to the invention, with forces transmitted from the drive unit 5 by way of a gear 22 to a toothed belt 17 that runs on rollers 18 . Also visible is the drive unit regulator 10 . The supply of power to the electrical components is by way of a conductive connection 29 . Visible in FIG. 1 a is the movable furniture part 3 in the closed end position, in which the front panel 26 of the movable furniture part 3 lies directly against the front side of the arrangement 7 according to the invention. Not shown is the fact that a user (not illustrated) is exerting a pull on the handle element 28 , as a result of which the movable furniture part 3 moves into the triggered condition, illustrated in FIG. 1 b.
FIG. 2 a once again shows the arrangement illustrated in FIGS. 1 a and 1 b , with the movable furniture part 3 in the meantime moved into the opened end position. Visible is one of the two lateral frames 14 on which the movable furniture part 3 is mounted. After another actuation (not illustrated) by a user (not illustrated), the movable furniture part 3 in FIG. 2 b is in a location between the opened end position and the closed end position.
Illustrated in FIGS. 3 a , 3 b and 3 c is an arrangement according to the invention in a touch-latch construction. It is clear from FIG. 3 a and from the detail in FIG. 3 b that with a variant of this kind there is a gap 30 between the front side of the arrangement according to the invention and the front panel 26 of the movable furniture part 3 , even in the closed end position of the movable furniture part 3 . This allows the movable furniture part 3 to be opened in a manner similar to the prior art known with such constructions, with the result that it will not be explained in more detail here. It goes without saying that it would be possible with a construction of this kind for support by the drive unit 5 to take place only once the movable furniture part 3 has been triggered, that is to say for example in the condition illustrated in FIG. 3 c . This accords with the basic idea that the user should notice the support given by the drive unit as little as possible. However, it is also possible to provide immediate support, at least on the pull-out movement following pressure against the front panel.
FIG. 4 a shows a further example embodiment of an arrangement according to the invention, with the actuating element 11 of an initialization device 6 included in the drive unit. FIG. 4 b shows in a detail that in the closed end position of the movable furniture part 3 there is a spacing between the rear side of the movable furniture part 3 and the actuating element 11 , with the result that the actuating element 11 is actuated by the movable furniture part 3 without making contact. This is possible, for example, with an actuating element 11 constructed as an inductive sensor. FIG. 4 c shows the movable furniture part 3 from FIGS. 4 a and 4 b in the triggered condition.
FIG. 5 a shows, in a perspective view, one of the two frames 14 provided for lateral mounting on the inside of an arrangement according to the invention, with the two rollers 18 that are arranged on the frame and have corresponding teeth for the toothed belt 17 running over the rollers 18 visible. FIG. 5 b shows, in a detail view, the drive unit 5 with the drive unit regulator 10 , which in this example embodiment drives one of the rollers 18 and hence the toothed belt 17 by way of the gear 22 that is partly integrated in the drive unit 5 . For reasons of clarity, the movable furniture part 3 has not been illustrated.
FIG. 6 shows a further example embodiment in which both lateral frames 14 , 15 are visible, with the drive unit 5 and the gear 22 included therein being secured, in the region between the frames, to the rear wall (not illustrated) of the arrangement according to the invention. For reasons of clarity, the movable furniture part 3 secured to the frames 14 , 15 has not been illustrated.
FIGS. 7 a and 7 b show an example embodiment in which the connection shaft 19 by way of which the drive unit 5 is connected to the rollers 18 of the two frames 15 is visible. In the detail of FIG. 7 b it is clear in this example embodiment that the forces are exerted by way of an interposed gear 22 .
FIG. 8 a shows the arrangement from FIGS. 7 a and 7 b from another angle of view, with the result that the connection for the drive unit 5 to exert force by way of the connection shaft 19 on a roller 18 of the frame 15 further away from the drive unit 5 is visible.
FIG. 9 shows a perspective view of an example embodiment of the arrangement 7 according to the invention, which has three movable furniture parts 3 with front panels 26 and handle elements 28 . The movable furniture part 3 that is mounted uppermost is visible, in particular a side wall 12 and the rear wall 16 thereof. Part of the conductive connection 29 is visible through the cut-away portion.
FIG. 10 shows, similarly to FIG. 9 , a variant on the arrangement according to the invention, in which a touch-latch construction is provided. Accordingly, no handle elements are provided on the front panels 26 .
FIG. 11 a once again shows the arrangement according to the invention from FIG. 10 , with the movable furniture part 3 that is mounted uppermost having been brought into the opened end position. On the inside of the arrangement 7 according to the invention, the frame 14 that is mounted on the side wall and comprises two parts, whereof the upper part is constructed to be movable, while the lower part is secured to a side wall of the arrangement 7 according to the invention, is visible. The detail view 11 b shows the drive unit 5 with the drive unit regulator 10 and the gear 22 , the roller 18 , the toothed belt 17 and part of the power supply 29 .
FIG. 12 a shows a disk 23 of conductive material that corresponds to the prior art, is mounted to be rotatable and is part of a magnetic encoder (not illustrated in more detail), with the disk 23 connected to be rotatable with the drive unit 5 by way of a shaft (not illustrated). Further visible are inductive sensors 27 that are arranged directly over one of the two surfaces of the disk 23 . As soon as the user exerts a force on the movable furniture part 3 (not illustrated here), the disk 23 , connected to the drive unit 5 , is set in rotary motion, with the result that the inductive sensors 27 pass on signals of the shape illustrated in FIG. 12 c to the regulating unit 1 , depending on whether they are located above conductive material of the disk 23 or above an air gap. As a result of the construction as a two-channel decoder, illustrated in these figures, it is possible to establish the speed of rotation from the width of the individual impulses between the two channels, and the direction of rotation of the disk 23 and hence of the drive unit 5 connected thereto from the phase angle of the individual impulses, and so to relate back therefrom to arrive at the linear movement of the movable furniture part 3 . Thus, as soon as the user puts the movable furniture part 3 in motion in either direction, the regulating device 1 detects this through the electrical signals coming from the position measuring device 4 , of which in this example embodiment the disk 23 and the sensors 27 form a part, and by way of an interposed drive unit regulator 10 gives the drive unit 5 the command for accelerating the movable furniture part 3 in the direction intended by the user. FIG. 12 b shows a perspective view of the two components 23 and 27 from FIG. 12 a . FIG. 12 d shows elements of a position measuring device 4 of a further example embodiment that, in the present case, is constructed as an optical encoder and in this case of course at the same time forms an acceleration measuring device 2 . Visible are light-emitting elements 25 whereof light falls by way of a screen 31 onto light-detecting elements 24 unless it is interrupted by the interposed rotating disk 23 . The details of such measuring means can be found in the relevant literature of the art.
FIGS. 13 a , 13 b and 13 c show, with the aid of distance/time graphs, a typical actuation procedure by way of example, in the course of which the movable furniture part 3 is moved from its closed end position into an intermediate position in which it comes to rest temporarily and, after another actuation by the user, is moved into the opened end position or alternatively into the closed end position again. In this example embodiment, by way of example, the assumption is made of a total distance S of approximately 0.43 m between the closed end position and the opened end position. The closed end position corresponds to the origin of the y axis, zero, in the distance/time graphs. In the construction as a touch-latch item of furniture, it goes without saying that the closed end position corresponds to a position of the movable furniture part 3 in which a gap 30 remains between its front panel 31 and the front side of the arrangement according to the invention. It is clear from FIG. 13 a that within a first time span t 0 after actuation by the user an even acceleration of the movable furniture part 3 is performed by the drive unit 5 over a partial distance S 1 to support the opening movement. The subsequent movement of the movable furniture part 3 is performed only under the action of the friction inherent in the system, with the result that the movable furniture part 3 finally comes to rest in an intermediate position (here approximately at the 0.22 m point). FIG. 13 b shows a possible profile in which the user exerts another pull on the movable furniture part 3 located in the intermediate position after a certain period, as a result of which the regulating unit 1 transmits to the drive unit 5 , by way of the drive unit regulator 10 , the command for accelerating the movable furniture part 3 evenly in the direction of the pulling acceleration performed. For this reason, visible in FIG. 13 b are another evenly accelerated movement of the movable furniture part 3 by the drive unit 5 over a partial distance S 2 , an interposed movement only under the action of the frictional force inherent in the system, which results in a certain braking of the movable furniture part 3 , and another evenly accelerated movement over a partial distance S 3 , with this time the acceleration by the drive unit 5 being opposed to the current speed of the movable furniture part 3 and so resulting in braking. In consequence thereof, the movable furniture part 3 comes to rest in the opened end position at negligible final speed, or at a speed of zero. In other words, the partial distance S 3 is a braking distance predetermined at the factory, which ensures safe braking of the movable furniture part 3 when it moves into the opened end position. For the user, this takes the form of an increased frictional effect in the region S 3 . FIG. 13 c shows a similarly possible shape for the profile, in which the user accelerates the movable furniture part 3 located in an intermediate position in the direction of the closed end position by the action of pushing. Once again visible is the immediately active supporting effect of the drive unit 5 , which is mirrored in the evenly accelerated movement of the movable furniture part 3 over the partial distance S 2 in the distance/time graph. Also visible is a protective distance S 3 that occurs before the closed end position and in which the drive unit 5 brings about an evenly accelerated braking movement of the movable furniture part 3 in order to move the latter into the closed end position reliably and without generating unnecessary noise. It is clear that the partial distance lying between the partial distances S 2 and S 3 has been covered only under the action of the friction inherent in the system, in accordance with the basic idea of the invention. The partial distances S 1 , S 2 , S 3 , illustrated in FIGS. 13 a , 13 b , 13 c , of the total distance S between the closed end position and the open end position are conventionally pre-set at the factory. This is in accordance with the idea that the user does not want to be bothered with technical details. It goes without saying that it would be possible to provide for a user who is somewhat more comfortable technically to set the partial distances S 1 , S 2 , S 3 or the time span to over which an acceleration occurs within certain limits (that is to say, taking into account safety aspects) himself or herself.
FIG. 14 illustrates diagrammatically the way in which the individual components of the arrangement according to the invention exchange information with one another. Visible diagrammatically is the regulating device 1 , which includes a drive unit regulator 10 and an actual-value calculating device 8 . The position measuring device 4 can pass on signals to the actual-value calculating device 8 and has the capacity itself to receive signals from the initialization device 6 , which is in turn capable of being triggered by way of actuating elements 20 , 11 , 9 . The drive unit regulator 10 receives signals from the acceleration measuring device 2 and the actual-value calculating device 8 . The diagrammatic logical illustration of the flow of information between the system elements does not necessarily correspond to the physical arrangement thereof. For example, all the system elements may be arranged together in an integrated construction, physically in the arrangement 7 according to the invention, to save space. Frequently, it is also possible for a component that is present as a single part in physical form to take over a plurality of logical functions, as is the case for example with resolvers and optical or magnetic encoders. These may simultaneously serve as a position measuring device 4 and an acceleration measuring device 2 . The angle of rotation of the disk of an optical or magnetic encoder on the one hand gives, for example, the possibility of an incremental determination of the position, and on the other hand just the fact that the disk is set in rotational motion and the detected change in speed give the possibility of measuring the acceleration. It goes without saying that an absolute position measurement may also be provided. Furthermore, there is the possibility of using a tachometer as a combined position and speed measuring device.
FIGS. 15 a and 15 b show diagrammatically, in side and plan view of the base surface of the movable furniture part 3 , a conceivable arrangement of the system units. Visible in FIG. 15 a is a side face 13 of the movable furniture part 3 with a front panel 26 , in this example embodiment the arrangement 7 according to the invention being constructed as a touch-latch construction. The movable furniture part 3 is connected to a belt 17 that is for its part connected by way of two rollers 18 to a drive unit 5 . In this example embodiment, forces are transmitted to both sides with the aid of a connection shaft 19 . Forces are transmitted from the drive unit 5 in this example embodiment by way of two gears 22 that are arranged to left and right of the drive unit and are connected to the connection shaft 19 . Also visible is an acceleration measuring device 2 that is arranged between a gear 22 and the drive unit 5 . The other system components, such as the position measuring device 4 , the actual-value calculating device 8 , the drive unit regulator 10 , the initialization device 6 and any actuating elements thereof, have not been illustrated in FIGS. 15 a and 15 b . They may be integrated in the system components illustrated as described above, in a manner known to the average person skilled in the art, and thus perform their functions.
In all the figures, the illustration and description of details corresponding to the prior art, and modes of functioning known to the average person skilled in the art, have been omitted. | An arrangement having at least one movable furniture part, in particular having a drawer or the like, having at least one drive unit and at least one regulating device for regulating the at least one drive unit, wherein the arrangement ( 7 ) has at least one, preferably analog, acceleration measuring device ( 2 ), with the at least one acceleration measuring device ( 2 ) generating an acceleration signal that is characteristic of accelerations caused by forces applied to the at least one movable furniture part ( 3 ) from the outside and that may be supplied to the at least one regulating device ( 1 ). | Condense the core contents of the given document. | [
"FIELD OF INVENTION The present invention relates to an arrangement having at least one movable furniture part, in particular having a drawer or the like, having at least one drive unit and at least one regulating device for regulating the at least one drive unit.",
"DESCRIPTION OF RELATED ART Arrangements of this kind are in principle already known.",
"For example, U.S. Pat. No. 5,158,347 describes an item of office furniture in which the drawers are moved by a motor over a first region of the entire opening distance once an identification code has been input.",
"EP 0 957 225 describes an opening means for a closure element, for example a drawer, that is triggered by way of a capacitor that discharges electrically when touched by the user.",
"Here too, the drawer is only moved partly out of the furniture carcass.",
"German patent specification DE 10 17 351 describes a device for pulling drawers out of or pushing them into items of furniture, which may be triggered by push buttons arranged on the carcass.",
"In this case, by using the push buttons, any possible position for the drawer along the entire opening distance is possible.",
"In this case, it is problematic that such opening aids always have to be triggered by way of actuating elements provided specifically therefor, which many users find awkward.",
"Particularly for those people who are skeptical about technology in general, it would be advantageous if it were possible to operate driven movable furniture parts in the good old-fashioned way, by pushing or pulling on the drawer.",
"SUMMARY OF THE INVENTION The object of the present invention is to provide a generic arrangement that makes it possible to operate intuitively a movable furniture part that is driven by a drive unit.",
"This object is achieved in accordance with the invention in that the arrangement has at least one, preferably analog, acceleration measuring device, with the at least one acceleration measuring device generating an acceleration signal that is characteristic of accelerations caused by forces applied to the at least one movable furniture part from the outside and that may be supplied to the at least one regulating device.",
"It is technically advantageous herein that in the arrangement according to the invention there are no longer any actuating elements of any kind provided to trigger the drive unit for the movable furniture parts.",
"It is economically advantageous herein that a greater level of acceptance on the market is to be expected for the arrangement according to the invention.",
"It is not significant whether the acceleration is measured directly or calculated from other measured variables.",
"In this sense, a device for determining the position of the movable furniture part combined with a clock also forms an acceleration measuring device.",
"In this case, the speed can be determined from the distance covered in a given time span, and the acceleration can be determined from the change in speed.",
"According to the invention, however, recognition of the fact that an acceleration of the movable furniture part has taken place is already sufficient, regardless of the magnitude or direction of the acceleration.",
"Advantageously, in one embodiment of the invention it is provided for the at least one drive unit to include an electric motor.",
"Extremely small electric motors of this kind are commercially available and guarantee problem-free operation with a low current consumption.",
"A particularly advantageous embodiment of the invention results when the acceleration signal contains information on the magnitude and/or direction, preferably the directional component parallel to the direction of pulling out the movable furniture part, of the acceleration caused by forces applied to the movable furniture part from the outside.",
"This allows the acceleration measuring device to make information available to the regulating device about the direction in which actuation of the draw should be performed.",
"If the regulating device receives, for example, from the acceleration measuring device the signal of a pulling acceleration being present, it can immediately send the drive unit a control command to move the movable furniture part in the direction of the measured pulling acceleration.",
"In this case, which opening condition the draw is in at the time of external actuation has no significance per se.",
"Advantageously, however, it is provided that, in a certain region before the opened and closed end positions of the movable furniture part, there is no longer a driven movement of the furniture part, in order to prevent damage to the furniture part or the arrangement according to the invention.",
"For this purpose, it is advantageous for the arrangement to have at least one position measuring device that generates a position signal that is characteristic of the opening condition of the movable furniture part and may be supplied to the regulating device.",
"In this way, the regulating device can recognize at any time whether the movable furniture part is in the vicinity of one of the end positions.",
"Advantageously, the acceleration signal emitted by the acceleration measuring device to the regulating device also contains information on the magnitude of the acceleration of the movable furniture part that the user exerts on it.",
"It is possible for example to conclude from an acceleration of large magnitude that rapid opening or closing is desired, as a result of which the regulating device can actuate the drive unit in a manner corresponding to the situation.",
"An advantageous embodiment of the invention results when the drive unit accelerates the movable furniture part approximately evenly over a predetermined time span.",
"Because the acceleration of the movable furniture part is performed only over a predetermined time span, the illusion for the user that the furniture part is not driven is maintained.",
"Once the time span has expired, the movable furniture part is braked by the friction inherent in the system just as though no drive unit were present.",
"However, it would also be possible to provide for a lower acceleration to be maintained after the time span of acceleration, in order to compensate the braking caused by the friction.",
"This maintains the impression of a non-driven furniture part that is, for example, mounted in a manner with particularly low friction.",
"Alternatively, or in addition, it may also be provided for the drive unit to accelerate the movable furniture part only over a predeterminable or predetermined partial distance whereof the length is shorter than the length of the total distance between the closed end position and the opened end position of the movable furniture part.",
"Because the drive unit is not active over the entire opening distance, the sought invisibility of the technology is maintained.",
"It may also be provided for the movement of the movable furniture part by the drive unit to be independent of the magnitude of the pulling or pushing acceleration.",
"As a result of this, the user is the only one to decide, through the magnitude of force he or she applies, how fast the movement of the movable furniture part is to be, with the drive unit always providing the same supporting acceleration.",
"A particularly advantageous embodiment of the invention results when the regulating device has an actual-value calculating device that calculates, from the position signal generated by the position measuring device, the current actual position and/or the current actual speed of the movable furniture part.",
"As a result of knowing the current position and speed of the movable furniture part, it is possible for the drive unit to perform an acceleration over defined partial distances, for example in the vicinity of the end positions of the movable furniture part, in such a way that the movable furniture part comes to a standstill in the respective end position.",
"In a further advantageous embodiment of the invention, it is provided for the arrangement to include at least one initialization device that generates a signal that is characteristic of certain predetermined positions of the movable furniture part in each case and may be supplied at least to the position measuring device.",
"If the arrangement according to the invention is not equipped with expensive non-erasable electronic memory elements, then once the arrangement according to the invention has been disconnected from the voltage source, for example, the position of the movable furniture part in relation to the arrangement according to the invention must be established.",
"Because the arrangement according to the invention is moreover commercially available in variously sized formats, the length of the total distance between the closed and the opened end positions of the movable furniture part and the positions of the movable furniture part in the closed and opened end positions must be established, at least on first start-up.",
"This can be done for example by the user triggering the initialization device by way of an actuating element that is readily accessible from outside the arrangement, for example a button.",
"With an initialization procedure of this kind, it may for example be provided for the user to move the movable furniture part into the closed end position, to actuate the actuating element there and then to move the movable furniture part into the opened end position and to actuate the actuating element again.",
"The result of this is that the information required about the total length of the movement of the movable furniture part and about the position of the movable furniture part in the particular positions is available to the regulating device.",
"Alternatively, or in addition, initialization by a collision recognition would also be possible.",
"In this case, the movable furniture part would travel slowly in the direction of one of the two end positions and, on reaching this, automatically trigger the initialization device as a result of the detected collision.",
"For example, the drive unit could first move the movable furniture part in the direction of the closed end position and, when the front panel collided with the front side of the arrangement, the zero position could be automatically established by the initialization device.",
"After that the drive unit could move the movable furniture part in the direction of the opened end position and, on collision, this position could be automatically established by the initialization device.",
"The collision itself could for example be detected by a sudden rise in the current supplied to the drive unit, with the rise being attributable to those forces occurring between the movable furniture part and the arrangement that the drive unit attempts to overcome.",
"It goes without saying that if a certain level of current were exceeded, it would cause the drive unit to be switched off in order to prevent damage.",
"It would also be possible to trigger the initialization device if the magnitude of the speed of the movable furniture part over a predetermined time span were less than or equal to a predetermined limit value, for example zero.",
"With a touch-latch construction, the closed end position established by the initialization device would of course not be the position of the movable furniture part on collision, but a position lying further out by a predetermined distance.",
"This would ensure the gap required for the touch-latch triggering between the front side of the arrangement and the front panel of the movable furniture part in the closed end position.",
"In a further advantageous embodiment of the invention, it is provided for the initialization device to be capable of being triggered by way of an actuating element that is arranged within the arrangement and is actuable by the movable furniture part.",
"This removes the need for the user to actuate a special actuating element.",
"An actuating element of this kind, arranged within the arrangement, may for example be constructed as a limit switch for determining the closed end position of the movable furniture part.",
"For example, it may be provided for this limit switch to be constructed as a pressure switch.",
"When the movable furniture part is pushed in, either by way of the drive unit or by the user, the limit switch is actuated by the movable furniture part over the last few millimeters of the distance of pushing in.",
"As a result, the closed end position of the movable furniture part in the arrangement according to the invention is established.",
"It may also be provided for the limit switch or the actuating element to be constructed in general as an inductive or capacitive sensor, with the result that the respective end positions of the movable furniture part may be detected without making contact.",
"Other types of sensor known to those skilled in the art may also be provided.",
"It is also conceivable for the initialization device to be capable of being triggered by making a conductive connection between the arrangement and a voltage source by way of a triggering element.",
"As a result, initialization takes place automatically on first start-up or when the voltage supply is re-established after a power failure.",
"It goes without saying that it is also possible to provide for two more constructions of the above-mentioned types of actuation of the initialization device to be combined in an arrangement according to the invention.",
"It goes without saying that triggering of the initialization device may also be performed by its being manually pulled out.",
"In this case, the movable furniture part is moved manually by a user, for example out of the closed end position into the fully opened end position.",
"In a further advantageous embodiment of the invention, it is provided for the movable furniture part to be mounted movably on frames arranged laterally within the arrangement.",
"Frames of this kind, which are per se part of the prior art, allow a low-friction and secure mounting of the movable furniture part in the arrangement according to the invention.",
"In a further advantageous embodiment of the invention, it is provided for the drive unit to be attached to a frame.",
"This may for example make a separate drive unit available for each movable furniture part.",
"It may also be possible to attach frames to which drive units are secured in an arrangement according to the invention from the outset.",
"In a further advantageous embodiment of the invention, it is provided for the drive unit to be attached to the inner face of the arrangement opposite the rear wall of the movable furniture part, preferably at approximately the same spacing from the two side walls of the arrangement.",
"This allows the movable furniture part to be accelerated largely without tilting when the drive unit is arranged centrally.",
"In a further advantageous embodiment of the invention, it is provided for the drive unit to be in constant connection with the movable furniture part.",
"This makes it possible for the movable furniture part to be accelerated by the drive unit, regardless of the current position of the movable furniture part in relation to the arrangement according to the invention.",
"For this, it is useful if for example the drive unit is in constant connection with the movable furniture part by way of at least one cable or a belt, preferably a toothed belt, or by way of a toothed wheel engaging in a toothed rack.",
"The use of a toothed belt in this case guarantees a slip-free connection between the movable furniture part and the drive unit.",
"Force may be exerted for example by the belt running over at least two rollers that are arranged on a lateral frame.",
"It goes without saying that it is also possible for both lateral frames to be constructed to have at least two rollers, over which a respective belt is guided for the transmission of forces.",
"It also goes without saying that the use of a cable without slip would be possible if both cable ends were fixed to the driven roller and so the one cable end were unwound and the other cable end wound up at the same time.",
"Above a certain width of the movable furniture part, it is advantageous if at least two rollers arranged on different frames are in a—preferably rigid—connection with one another by way of a connection shaft, and so may be moved by the drive unit.",
"A further advantageous embodiment of the invention results from at least one roller on at least one frame being drivable by the drive unit.",
"This enables forces to be transmitted with lower losses than would be achievable if transmission devices were interposed between the drive unit and the movable furniture part.",
"In order to achieve more advantageous transmission of the movement of the drive unit to the movable furniture part, it may be provided for the at least one roller on at least one frame to be drivable by the drive unit by way of a gear.",
"With a wide movable furniture part, it is again useful if gears are provided at both ends of the connection shaft.",
"With very wide movable furniture parts, it may also be provided for drive units to be arranged on both sides of the movable furniture part, these drive units either having their own regulating devices and a synchronization means, or being capable of being controlled by a common regulating device.",
"In a further advantageous embodiment of the invention, it may be provided for the arrangement to include a resolver for measuring the position and/or speed and/or acceleration of the movable furniture part, whereof the signals may be supplied to the regulating device.",
"Resolvers of this kind are commercially available and are extremely robust both mechanically and thermally.",
"A resolver of this kind is constructed in accordance with the principle of a rotary transformer.",
"Commercially available resolvers are frequently available with an integrated evaluation circuit, with the result that the signal thereof can be supplied directly to the regulating device.",
"In a further advantageous embodiment of the invention, it may be provided for the arrangement to include an optical encoder for measuring the position and/or speed and/or acceleration of the movable furniture part, whereof the signals may be supplied to the regulating device.",
"Optical or indeed magnetic encoders of this kind represent a low-cost and frequently also space-saving alternative to resolvers.",
"At the same time, they still guarantee a satisfactory angular range of triggering for an arrangement according to the invention, for example from 64 to 1024 pulses/revolution.",
"Certain disadvantages with optical and magnetic encoders are produced from their sensitivity to mechanical vibration, soiling and the lack of absolute angle information at the time of switching on, with the result that encoders of this kind can only determine positions incrementally.",
"In a further advantageous embodiment of the invention, it is provided for the drive unit to include a brushless d.c. motor and for measurement of the position and/or speed and/or acceleration of the movable furniture part to be made directly by way of the commutator signal, with it being possible to supply the signals obtained in this way to the regulating device.",
"Frequently, brushless motors of this kind are commercially available with a Hall-effect sensor construction.",
"Nowadays, extremely small electric motors are already available in which an electronic, optical or magnetic position measuring device is already integrated in the electric motor, which saves both space and time on installation.",
"The present invention furthermore relates to a process for moving a movable furniture part, in particular a draw, that is mounted in or on an arrangement, by a drive unit, in particular an electric motor, with the arrangement having a drive unit regulator and a position measuring device, wherein the position measuring device sends the drive unit regulator signals and the drive unit regulator gives the drive unit the command for accelerating the movable furniture part in dependence on these signals.",
"The position measuring device in this case represents a particularly simple way of realizing the acceleration measuring device, as already mentioned.",
"For example, it may be provided, in the event of a change in the movement condition of the movable furniture part that is caused from the outside, for the position measuring device to send a signal to the drive unit regulator and for the latter to give the drive unit the command for accelerating the movable furniture part.",
"It goes without saying that a change in the movement condition should be understood—as is customary in physics—to include both starting up of the movable furniture part and a change in the speed of a movable furniture part performing an even movement.",
"However, it may also be provided, once the movable furniture part has moved over a predeterminable or predetermined distance, for the position measuring device to send a signal to the drive unit regulator and for the latter to give the drive unit the command for accelerating the movable furniture part.",
"This case is thus purely a matter of distance measurement.",
"The drive unit is activated as soon as the movable furniture part has covered the predetermined distance.",
"The time required therefor has no effect.",
"With this triggering process, advantageously it may furthermore advantageously be provided for the distance to be covered by the movable furniture part, in accordance with which the position measuring device emits a signal to the drive unit regulator, to be adjustable or adjusted differently depending on the direction of movement of the movable furniture part.",
"For example, a distance of 1 millimeter could be selected as the activation distance for triggering a movement directed away from the furniture carcass, whereas triggering of a movement directed toward the furniture carcass takes place after a distance of 10 millimeters.",
"BRIEF DESCRIPTION OF THE DRAWINGS Further advantages and details of the arrangement according to the invention will become apparent from the figures below and from the associated description of the figures, in which: FIGS. 1 a and 1 b show an arrangement according to the invention, partly in cross-section, with the movable furniture part in the closed end position and in the triggered condition, FIGS. 2 a and 2 b show an arrangement according to the invention, partly in cross-section, with the movable furniture part in the opened end position and in an intermediate position, FIGS. 3 a , 3 b and 3 c show a variant on an arrangement according to the invention, partly in cross-section, with the movable furniture part in the closed end position, an associated detail view, and with the movable furniture part in the triggered condition, FIGS. 4 a , 4 b and 4 c show an example embodiment of an arrangement according to the invention, partly in cross-section, with the movable furniture part in the closed end position, a detail view thereof, and with the movable furniture part in the triggered condition, FIGS. 5 a and 5 b show a perspective view of components of an arrangement according to the invention and a detail view, FIG. 6 shows a further perspective view of components of an example embodiment of an arrangement according to the invention, FIGS. 7 a and 7 b show a further perspective view of an example embodiment of an arrangement according to the invention, and a detail view, FIGS. 8 a and 8 b show the same subject as FIGS. 7 a and 7 b from a different angle of view, FIG. 9 shows a perspective view of an example embodiment of an arrangement according to the invention, FIG. 10 shows a perspective view of a further example embodiment of an arrangement according to the invention, FIGS. 11 a and 11 b show perspective views of a further example embodiment of an arrangement according to the invention, with a movable furniture part in the opened end position, and a detail view, FIGS. 12 a , 12 b , 12 c and 12 d show diagrammatic illustrations of components of an arrangement according to the invention, FIGS. 13 a , 13 b and 13 c show distance/time graphs that describe by way of example the actuation of an arrangement according to the invention, FIG. 14 shows a diagrammatic illustration of the flow of information between individual diagrammatically illustrated logical components of the arrangement according to the invention, and FIGS. 15 a and 15 b show a diagrammatic illustration of an arrangement according to the invention, from different angles of view.",
"DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Visible in FIG. 1 a is a movable furniture part 3 , constructed as a drawer, in a view toward one of its side faces 12 .",
"It can be seen that the drawer is constructed with a handle 28 .",
"The movable furniture part 3 is mounted such that it is linearly movable in an arrangement 7 according to the invention, with forces transmitted from the drive unit 5 by way of a gear 22 to a toothed belt 17 that runs on rollers 18 .",
"Also visible is the drive unit regulator 10 .",
"The supply of power to the electrical components is by way of a conductive connection 29 .",
"Visible in FIG. 1 a is the movable furniture part 3 in the closed end position, in which the front panel 26 of the movable furniture part 3 lies directly against the front side of the arrangement 7 according to the invention.",
"Not shown is the fact that a user (not illustrated) is exerting a pull on the handle element 28 , as a result of which the movable furniture part 3 moves into the triggered condition, illustrated in FIG. 1 b. FIG. 2 a once again shows the arrangement illustrated in FIGS. 1 a and 1 b , with the movable furniture part 3 in the meantime moved into the opened end position.",
"Visible is one of the two lateral frames 14 on which the movable furniture part 3 is mounted.",
"After another actuation (not illustrated) by a user (not illustrated), the movable furniture part 3 in FIG. 2 b is in a location between the opened end position and the closed end position.",
"Illustrated in FIGS. 3 a , 3 b and 3 c is an arrangement according to the invention in a touch-latch construction.",
"It is clear from FIG. 3 a and from the detail in FIG. 3 b that with a variant of this kind there is a gap 30 between the front side of the arrangement according to the invention and the front panel 26 of the movable furniture part 3 , even in the closed end position of the movable furniture part 3 .",
"This allows the movable furniture part 3 to be opened in a manner similar to the prior art known with such constructions, with the result that it will not be explained in more detail here.",
"It goes without saying that it would be possible with a construction of this kind for support by the drive unit 5 to take place only once the movable furniture part 3 has been triggered, that is to say for example in the condition illustrated in FIG. 3 c .",
"This accords with the basic idea that the user should notice the support given by the drive unit as little as possible.",
"However, it is also possible to provide immediate support, at least on the pull-out movement following pressure against the front panel.",
"FIG. 4 a shows a further example embodiment of an arrangement according to the invention, with the actuating element 11 of an initialization device 6 included in the drive unit.",
"FIG. 4 b shows in a detail that in the closed end position of the movable furniture part 3 there is a spacing between the rear side of the movable furniture part 3 and the actuating element 11 , with the result that the actuating element 11 is actuated by the movable furniture part 3 without making contact.",
"This is possible, for example, with an actuating element 11 constructed as an inductive sensor.",
"FIG. 4 c shows the movable furniture part 3 from FIGS. 4 a and 4 b in the triggered condition.",
"FIG. 5 a shows, in a perspective view, one of the two frames 14 provided for lateral mounting on the inside of an arrangement according to the invention, with the two rollers 18 that are arranged on the frame and have corresponding teeth for the toothed belt 17 running over the rollers 18 visible.",
"FIG. 5 b shows, in a detail view, the drive unit 5 with the drive unit regulator 10 , which in this example embodiment drives one of the rollers 18 and hence the toothed belt 17 by way of the gear 22 that is partly integrated in the drive unit 5 .",
"For reasons of clarity, the movable furniture part 3 has not been illustrated.",
"FIG. 6 shows a further example embodiment in which both lateral frames 14 , 15 are visible, with the drive unit 5 and the gear 22 included therein being secured, in the region between the frames, to the rear wall (not illustrated) of the arrangement according to the invention.",
"For reasons of clarity, the movable furniture part 3 secured to the frames 14 , 15 has not been illustrated.",
"FIGS. 7 a and 7 b show an example embodiment in which the connection shaft 19 by way of which the drive unit 5 is connected to the rollers 18 of the two frames 15 is visible.",
"In the detail of FIG. 7 b it is clear in this example embodiment that the forces are exerted by way of an interposed gear 22 .",
"FIG. 8 a shows the arrangement from FIGS. 7 a and 7 b from another angle of view, with the result that the connection for the drive unit 5 to exert force by way of the connection shaft 19 on a roller 18 of the frame 15 further away from the drive unit 5 is visible.",
"FIG. 9 shows a perspective view of an example embodiment of the arrangement 7 according to the invention, which has three movable furniture parts 3 with front panels 26 and handle elements 28 .",
"The movable furniture part 3 that is mounted uppermost is visible, in particular a side wall 12 and the rear wall 16 thereof.",
"Part of the conductive connection 29 is visible through the cut-away portion.",
"FIG. 10 shows, similarly to FIG. 9 , a variant on the arrangement according to the invention, in which a touch-latch construction is provided.",
"Accordingly, no handle elements are provided on the front panels 26 .",
"FIG. 11 a once again shows the arrangement according to the invention from FIG. 10 , with the movable furniture part 3 that is mounted uppermost having been brought into the opened end position.",
"On the inside of the arrangement 7 according to the invention, the frame 14 that is mounted on the side wall and comprises two parts, whereof the upper part is constructed to be movable, while the lower part is secured to a side wall of the arrangement 7 according to the invention, is visible.",
"The detail view 11 b shows the drive unit 5 with the drive unit regulator 10 and the gear 22 , the roller 18 , the toothed belt 17 and part of the power supply 29 .",
"FIG. 12 a shows a disk 23 of conductive material that corresponds to the prior art, is mounted to be rotatable and is part of a magnetic encoder (not illustrated in more detail), with the disk 23 connected to be rotatable with the drive unit 5 by way of a shaft (not illustrated).",
"Further visible are inductive sensors 27 that are arranged directly over one of the two surfaces of the disk 23 .",
"As soon as the user exerts a force on the movable furniture part 3 (not illustrated here), the disk 23 , connected to the drive unit 5 , is set in rotary motion, with the result that the inductive sensors 27 pass on signals of the shape illustrated in FIG. 12 c to the regulating unit 1 , depending on whether they are located above conductive material of the disk 23 or above an air gap.",
"As a result of the construction as a two-channel decoder, illustrated in these figures, it is possible to establish the speed of rotation from the width of the individual impulses between the two channels, and the direction of rotation of the disk 23 and hence of the drive unit 5 connected thereto from the phase angle of the individual impulses, and so to relate back therefrom to arrive at the linear movement of the movable furniture part 3 .",
"Thus, as soon as the user puts the movable furniture part 3 in motion in either direction, the regulating device 1 detects this through the electrical signals coming from the position measuring device 4 , of which in this example embodiment the disk 23 and the sensors 27 form a part, and by way of an interposed drive unit regulator 10 gives the drive unit 5 the command for accelerating the movable furniture part 3 in the direction intended by the user.",
"FIG. 12 b shows a perspective view of the two components 23 and 27 from FIG. 12 a .",
"FIG. 12 d shows elements of a position measuring device 4 of a further example embodiment that, in the present case, is constructed as an optical encoder and in this case of course at the same time forms an acceleration measuring device 2 .",
"Visible are light-emitting elements 25 whereof light falls by way of a screen 31 onto light-detecting elements 24 unless it is interrupted by the interposed rotating disk 23 .",
"The details of such measuring means can be found in the relevant literature of the art.",
"FIGS. 13 a , 13 b and 13 c show, with the aid of distance/time graphs, a typical actuation procedure by way of example, in the course of which the movable furniture part 3 is moved from its closed end position into an intermediate position in which it comes to rest temporarily and, after another actuation by the user, is moved into the opened end position or alternatively into the closed end position again.",
"In this example embodiment, by way of example, the assumption is made of a total distance S of approximately 0.43 m between the closed end position and the opened end position.",
"The closed end position corresponds to the origin of the y axis, zero, in the distance/time graphs.",
"In the construction as a touch-latch item of furniture, it goes without saying that the closed end position corresponds to a position of the movable furniture part 3 in which a gap 30 remains between its front panel 31 and the front side of the arrangement according to the invention.",
"It is clear from FIG. 13 a that within a first time span t 0 after actuation by the user an even acceleration of the movable furniture part 3 is performed by the drive unit 5 over a partial distance S 1 to support the opening movement.",
"The subsequent movement of the movable furniture part 3 is performed only under the action of the friction inherent in the system, with the result that the movable furniture part 3 finally comes to rest in an intermediate position (here approximately at the 0.22 m point).",
"FIG. 13 b shows a possible profile in which the user exerts another pull on the movable furniture part 3 located in the intermediate position after a certain period, as a result of which the regulating unit 1 transmits to the drive unit 5 , by way of the drive unit regulator 10 , the command for accelerating the movable furniture part 3 evenly in the direction of the pulling acceleration performed.",
"For this reason, visible in FIG. 13 b are another evenly accelerated movement of the movable furniture part 3 by the drive unit 5 over a partial distance S 2 , an interposed movement only under the action of the frictional force inherent in the system, which results in a certain braking of the movable furniture part 3 , and another evenly accelerated movement over a partial distance S 3 , with this time the acceleration by the drive unit 5 being opposed to the current speed of the movable furniture part 3 and so resulting in braking.",
"In consequence thereof, the movable furniture part 3 comes to rest in the opened end position at negligible final speed, or at a speed of zero.",
"In other words, the partial distance S 3 is a braking distance predetermined at the factory, which ensures safe braking of the movable furniture part 3 when it moves into the opened end position.",
"For the user, this takes the form of an increased frictional effect in the region S 3 .",
"FIG. 13 c shows a similarly possible shape for the profile, in which the user accelerates the movable furniture part 3 located in an intermediate position in the direction of the closed end position by the action of pushing.",
"Once again visible is the immediately active supporting effect of the drive unit 5 , which is mirrored in the evenly accelerated movement of the movable furniture part 3 over the partial distance S 2 in the distance/time graph.",
"Also visible is a protective distance S 3 that occurs before the closed end position and in which the drive unit 5 brings about an evenly accelerated braking movement of the movable furniture part 3 in order to move the latter into the closed end position reliably and without generating unnecessary noise.",
"It is clear that the partial distance lying between the partial distances S 2 and S 3 has been covered only under the action of the friction inherent in the system, in accordance with the basic idea of the invention.",
"The partial distances S 1 , S 2 , S 3 , illustrated in FIGS. 13 a , 13 b , 13 c , of the total distance S between the closed end position and the open end position are conventionally pre-set at the factory.",
"This is in accordance with the idea that the user does not want to be bothered with technical details.",
"It goes without saying that it would be possible to provide for a user who is somewhat more comfortable technically to set the partial distances S 1 , S 2 , S 3 or the time span to over which an acceleration occurs within certain limits (that is to say, taking into account safety aspects) himself or herself.",
"FIG. 14 illustrates diagrammatically the way in which the individual components of the arrangement according to the invention exchange information with one another.",
"Visible diagrammatically is the regulating device 1 , which includes a drive unit regulator 10 and an actual-value calculating device 8 .",
"The position measuring device 4 can pass on signals to the actual-value calculating device 8 and has the capacity itself to receive signals from the initialization device 6 , which is in turn capable of being triggered by way of actuating elements 20 , 11 , 9 .",
"The drive unit regulator 10 receives signals from the acceleration measuring device 2 and the actual-value calculating device 8 .",
"The diagrammatic logical illustration of the flow of information between the system elements does not necessarily correspond to the physical arrangement thereof.",
"For example, all the system elements may be arranged together in an integrated construction, physically in the arrangement 7 according to the invention, to save space.",
"Frequently, it is also possible for a component that is present as a single part in physical form to take over a plurality of logical functions, as is the case for example with resolvers and optical or magnetic encoders.",
"These may simultaneously serve as a position measuring device 4 and an acceleration measuring device 2 .",
"The angle of rotation of the disk of an optical or magnetic encoder on the one hand gives, for example, the possibility of an incremental determination of the position, and on the other hand just the fact that the disk is set in rotational motion and the detected change in speed give the possibility of measuring the acceleration.",
"It goes without saying that an absolute position measurement may also be provided.",
"Furthermore, there is the possibility of using a tachometer as a combined position and speed measuring device.",
"FIGS. 15 a and 15 b show diagrammatically, in side and plan view of the base surface of the movable furniture part 3 , a conceivable arrangement of the system units.",
"Visible in FIG. 15 a is a side face 13 of the movable furniture part 3 with a front panel 26 , in this example embodiment the arrangement 7 according to the invention being constructed as a touch-latch construction.",
"The movable furniture part 3 is connected to a belt 17 that is for its part connected by way of two rollers 18 to a drive unit 5 .",
"In this example embodiment, forces are transmitted to both sides with the aid of a connection shaft 19 .",
"Forces are transmitted from the drive unit 5 in this example embodiment by way of two gears 22 that are arranged to left and right of the drive unit and are connected to the connection shaft 19 .",
"Also visible is an acceleration measuring device 2 that is arranged between a gear 22 and the drive unit 5 .",
"The other system components, such as the position measuring device 4 , the actual-value calculating device 8 , the drive unit regulator 10 , the initialization device 6 and any actuating elements thereof, have not been illustrated in FIGS. 15 a and 15 b .",
"They may be integrated in the system components illustrated as described above, in a manner known to the average person skilled in the art, and thus perform their functions.",
"In all the figures, the illustration and description of details corresponding to the prior art, and modes of functioning known to the average person skilled in the art, have been omitted."
] |
The present application claims priority to Chinese Patent Application No. 200710121647.X, entitled “METHOD FOR DATA RE-TRANSMISSION DURING CELL HANDOVER IN LTE SYSTEM AND APPARATUS THEREOF”, filed with Chinese Patent Office on Sep. 11, 2007, which is incorporated herein in its entirety.
FIELD OF THE INVENTION
The present invention relates to the technical field of the Long Time Evolution (LTE) system in mobile communications, and particularly to a method for indicating data re-transmission during cell handover in the LTE system and a device thereof.
BACKGROUND OF THE INVENTION
During the cell handover in the LTE system, the idea of User Equipment (UE) assistant to network control, i.e., the steps of “measure-report-decide-execute”, is still adopted. When the Source Evolved Node B (S_eNB) decides that the UE shall handover to the Target Evolved Node B (T_eNB) according to measurement reports from the UE and the T_eNB, the S_eNB exchanges information with the T_eNB directly via an X2 interface, to complete resource preparation in the target cell; then, the S_eNB instructs the UE to handover to the target cell; after a successful handover, the T_eNB informs the S_eNB to release radio resource of the original cell. In addition, the S_eNB transmits data that is not transmitted yet to the T_eNB and updates relation of nodes between a user plane and a control plane.
Referring to FIG. 1 , a flowchart of cell handover in the LTE system in the prior art mainly includes:
[1] The S_eNB configures the UE with a measurement procedure;
[2] The UE sends a measurement report to the S_eNB;
[3] The S_eNB makes a UE handover decision according to the measurement report and Radio Resource Management (RRM) information;
[4] The S_eNB sends a handover request to the T_eNB;
[5] On receiving the handover request from the S_eNB, the T_eNB performs an admission control procedure according to the received E-RAB Quality of Service (QoS) information;
[6] The T_eNB sends a Handover Request Acknowledge message to the S_eNB;
[7] The S_eNB sends a Handover Command message to the UE, to instruct the UE to perform a handover;
[8] The UE sends a Synchronization message to the T_eNB;
[9] The T_eNB feeds a Synchronization Reply message back to the UE, the Synchronization Reply message including UL resource allocation information, a time advance, etc.;
[10] The UE sends a Handover Complete Acknowledge message to the T_eNB after the UE accesses the target cell successfully.
On the user plane, in order to avoid loss of uplink data from the UE and to maintain ordered transmission of the uplink data during the handover, an uplink data forwarding solution is adopted, which is performed between step [7] and step [8] of FIG. 1 (as illustrated by dotted lines). Generally, the data forwarding refers to that: the S_eNB forwards received disordered Packet Data Convergence Protocol-Service Data Units (PDCP-SDUs) to the T_eNB, and the PDCP-SDUs are attached with Sequence Numbers (SNs), then the T_eNB sends the received PDCP-SDUs to the Service Gateway (S-GW). During the handover, ordered transmission of upper layer PDUs is based on continuous PDCP-SNs and a re-order function provided by the PDCP layer. In the uplink, the re-order function of the PDCP layer of the T_eNB ensures the ordered transmission of the uplink PDCP-SDUs.
In the present LTE system, the air interface is based on the Automatic Repeat Request/Hybrid Automatic Repeat Request (ARQ/HARQ) mechanism. The S_eNB feeds ACKs back to the UE on successfully receiving ordered PDCP-SDUs. The UE re-transmits to the T_eNB those PDCP-SDUs whose ACKs are not received at the UE. It is not difficult to understand that the UE does not receive any ACK to a PDCP in two cases: in the first case, the S_eNB does not receive the PDCPs due to reasons such as network, etc., and does not feed ACKs back to the UE accordingly; in the second case, the S_eNB has received ordered PDCPs successfully, however, ACKs are not fed back to the UE successfully due to network reasons. The above second case may result in insignificant re-transmission from the UE to the T_eNB and a waste of precious radio resource. Examples are described hereinafter with reference to the two cases.
FIG. 2 illustrates a fact in which re-transmission of PDCP-SDUs from the UE results in an insignificant waste. The S_eNB receives data 1 , 2 and 3 from the UE successfully and transmits the data 1 , 2 and 3 to the S-GW via an S1 interface. It is assumed that the UE receives only an ACK to the data 1 fed back from the network side and does not receive ACKs to the data 2 and 3 . In this case, the UE continues to send the data 2 and 3 to the T_eNB, the T_eNB receives the data 2 and 3 and sends the re-transmitted data 2 and 3 to the S-GW, which results in reception of repeated data in the Evolved Packet Core (EPC) system and a waste of precious radio resource at the air interface.
FIG. 3 illustrates another fact in which re-transmission of PDCP-SDUs from the UE results in an insignificant waste. The UE sends data a, b, c and d to the S_eNB, however, the data b fails during transmission and the S_eNB receives only the data a, c and d, and the data c and d becomes disordered. According to the conventional solution of data forwarding, the S_eNB sends the ordered data a to the S-GW, buffers the disordered data c and d in a buffer, and then sends the data c and d to the T_eNB which delivers the data c and d to the S-GW. It is assumed that the UE does not receive any ACK to the data c and d. In this case, the UE receives only an ACK to the data a, and re-transmits the data b, c and d to the T_eNB because the UE does not receive any ACK to the data b, c and d. Apparently, the data c and d is re-transmitted. On one hand, the S_eNB sends the buffered data c and d to the T_eNB; on the other hand, the UE re-transmits the data c and d to the T_eNB due to no reception of any ACK, thereby resulting in a waste of resource.
SUMMARY OF THE INVENTION
In view of this, the present invention provides a method for indicating data re-transmission during cell handover in a Long Time Evolution (LTE) system, so as to solve the problem of waste of radio resource due to re-transmission of redundant PDCP-SDUs in the conventional solution.
Corresponding to the method, the present invention further provides a device for indicating data re-transmission during cell handover in a Long Time Evolution (LTE) system, i.e., an eNB, and a UE.
The technical solution of the present invention is described as follows:
A method for indicating data re-transmission during cell handover in a Long Time Evolution (LTE) system includes:
sending, by a Source Evolved Node B (S_eNB), a Packet Data Convergence Protocol-Service Data Unit Sequence Number (PDCP-SDU SN) report to a Target Evolved Node B (T_eNB), for informing of PDCP-SDU SNs that have been received by the S_eNB; and informing, by the T_eNB, User Equipment (UE) the PDCP-SDU SNs that have been received by the S_eNB.
The method further includes: discarding, by the UE, PDCP-SDUs that have been received by the S_eNB from a re-transmission queue according to the received PDCP-SDU SNs, and re-transmitting only the rest of PDCP-SDUs in the queue to the T_eNB.
The T_eNB informs the UE of the PDCP-SDU SNs received by the S_eNB through a synchronization reply message, a Radio Resource Control (RRC) message, a Radio Link Control (RLC) message or a Media Access Control (MAC) message.
Preferably, after the UE is synchronized with the T_eNB, the T_eNB determines whether the T_eNB has received the PDCP-SDU SN report; the T_eNB sends to the UE the synchronization reply message carrying the PDCP-SDU SNs that have been received by the S_eNB if the T_eNB has received the PDCP-SDU SN report; and the T_eNB sends to the UE the synchronization reply message carrying no PDCP-SDU SN if the T_eNB has not received the PDCP-SDU SN report.
Or, after the UE is synchronized with the T_eNB, the T_eNB determines whether the T_eNB has received the PDCP-SDU SN report; the T_eNB sends to the UE the synchronization reply message carrying the PDCP-SDU SNs that have been received by the S_eNB if the T_eNB has received the PDCP-SDU SN report; and if the T_eNB has not received the PDCP-SDU SN report, the T_eNB waits for a preset period of time, and sends to the UE the synchronization reply message carrying no PDCP-SDU SN if the T_eNB does not receive the PDCP-SDU SN report within the preset period of time; and the T_eNB sends to the UE the synchronization reply message carrying the PDCP-SDU SNs that have been received by the S_eNB if the T_eNB receives the PDCP-SDU SN report within the preset period of time.
Or, after the UE is synchronized with the T_eNB, the T_eNB determines whether the T_eNB has received the PDCP-SDU SN report; the T_eNB sends to the UE the synchronization reply message carrying the PDCP-SDU SNs that have been received by the S_eNB if the T_eNB has received the PDCP-SDU SN report; and if the T_eNB has not received the PDCP-SDU SN report, the T_eNB sends to the UE the synchronization reply message carrying no PDCP-SDU SN; and the T_eNB sends to the UE the RRC message, the RLC message or the MAC message immediately to inform the UE of the PDCP-SDU SNs that have been received by the S_eNB.
The time when the S_eNB sends the PDCP-SDU SN report to the T_eNB is when the S_eNB receives an acknowledge message to a handover command message fed back from the UE, or when a preset time arrives from the time of sending the handover command message from the UE if the S_eNB does not receive any acknowledge message to the handover command message.
An Evolved Node B (eNB) for indicating data re-transmission during cell handover in a Long Time Evolution (LTE) system includes: an X2 interface unit, a User Equipment (UE) interface unit communicated with UE, where the eNB further includes: a report assembling unit and a message assembling unit; the report assembling unit is adapted to assemble a Packet Data Convergence Protocol-Service Data Unit Sequence Number (PDCP-SDU SN) report including SNs of PDCP-SDUs received at the UE interface, the report being sent to the T_eNB via the X2 interface unit; the message assembling unit is adapted to assemble a message including PDCP-SDU SNs that have been received at the S_eNB according to the PDCP-SDU SN report received at the X2 interface unit, and send the message to the UE via the UE interface unit.
The message assembled by the message assembling unit is a synchronization reply message, a Radio Resource Control (RRC) message, a Radio Link Control (RLC) message or a Media Access Control (MAC) message.
A User Equipment (UE) for controlling data re-transmission during cell handover in a Long Time Evolution (LTE) system includes: an Evolved Node B (eNB) interface unit communicated with a Source Evolved Node B (S_eNB) or a Target Evolved Node B (T_eNB) and a re-transmission queue in which Packet Data Convergence Protocol-Service Data Units (PDCP-SDUs) are buffered, where the UE further includes: a message parsing unit and a queue adjustment unit; where the eNB interface unit is adapted to receive from the T_eNB a message indicating PDCP-SDU Sequence Numbers (SNs) that have been received by the S_eNB; the message parsing unit is adapted to parse the message to obtain the PDCP-SDU SNs that have been received by the S_eNB; the queue adjustment unit is adapted to discard the PDCP-SDU SNs that have been received by the S_eNB from the re-transmission queue, and the eNB interface unit re-transmits the rest of PDCP-SDUs in the re-transmission queue to the T_eNB.
The message indicating PDCP-SDU SNs that have been received by the S_eNB is a synchronization reply message, a Radio Resource Control (RRC) message, a Radio Link Control (RLC) message or a Media Access Control (MAC) message.
The above technical solution includes the following technical effects:
In the solution of cell handover in the LTE system according to the prior art, the UE re-transmits a PDCP to the T_eNB if only the UE does not receive an ACK to the PDCP. However, in the present invention, the UE further determines whether the UE has received from the T_eNB a PDCP-SN indicating that the S_eNB has received the PDCP. If the UE does not receive the ACK to the PDCP but receives the PDCP-SN indicating that the S_eNB has received the PDCP, the UE does not re-transmit the PDCP, thereby avoiding re-transmission of redundant PDCPs and resulting in effective saving of radio resource compared with the conventional solution.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram of cell handover in the LTE system in the prior art;
FIG. 2 is a first diagram of resending data from the UE in the prior art;
FIG. 3 is a second diagram of resending data from the UE in the prior art;
FIG. 4 is a diagram of a first embodiment of the method according to the present invention;
FIG. 5 is a flowchart of the first embodiment of the method according to the present invention;
FIG. 6 is an exemplary diagram of the first embodiment of the method according to the present invention;
FIG. 7 is a flowchart of a second embodiment of the method according to the present invention;
FIG. 8 is a flowchart of a third embodiment of the method according to the present invention;
FIG. 9 is a diagram of a structure of an S_eNB device according to the present invention;
FIG. 10 is a diagram of a structure of a T_eNB device according to the present invention; and
FIG. 11 is a diagram of a structure of a UE device according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The core of the present invention lies in that a process is added during cell handover of the UE, i.e., the S_eNB informs the UE via the T_eNB that which PDCP-SDUs have been received by the S_eNB successfully and the UE does not need to re-transmit the PDCP-SDUs even if the UE does not receive ACKs to the PDCP-SDUs.
Further, the present invention is implemented in the following manner:
1] The S_eNB sends a PDCP-SDU SN report to the T_eNB, to inform the T_eNB of PDCP-SDU SNs (including SNs of all ordered and unordered PDCP-SDUs) that have been received by the S_eNB;
2] The T_eNB re-transmits the PDCP-SDU SNs to the UE according to the report, to inform the UE which PDCP-SDUs have been received;
3] The UE does not re-transmit the PDCP-SDUs according to the received PDCP-SDU SNs.
In the solution of cell handover in the LTE system in the prior art, the UE re-transmits a PDCP-SDU to the T_eNB if only the UE does not receive an ACK to the PDCP-SDU. However, in the present invention, the UE further determines whether the UE has received from the T_eNB the SN indicating that the S_eNB has received the PDCP-SDU. If the UE does not receive an ACK to a PDCP-SDU but receives a PDCP-SDU SN indicating reception of the PDCP-SDU, the UE does not re-transmit the PDCP-SDU, thereby avoiding re-transmission of duplicate PDCP-SDU and resulting in effective saving of radio resource compared with the conventional solution.
Embodiments of the present invention are described in detail hereinafter with reference to the accompanying drawings.
It is not difficult to understand that a signaling is added in cell handover according to the present invention, so as to transmit the PDCP-SDU SNs that have been received by the S_eNB. The UE does not re-transmit the PDCP-SDUs. In order to make the whole procedure more clear, the procedure of cell handover in the LTE system, i.e., a modified solution based on the cell handover described in the background of the invention, is described hereinafter.
FIG. 4 is a diagram of cell handover in the LTE system according to the first embodiment. The cell handover includes the following steps:
In step 401 , the S_eNB configures the UE with a measurement procedure according to roaming restriction information.
The measurement information provided by the S_eNB may be of assistance to control the connection mobility function of the UE.
In step 402 , the UE sends a measurement report to the S_eNB.
In step 403 , the S_eNB makes a handover decision to perform cell handover of the UE according to the measurement report from the UE and RRM information.
In step 404 , the S_eNB sends to the T_eNB a Handover Request message carrying necessary information so that the T_eNB prepares handover resource. The Handover Request message also indicates whether the system supports DL/UL data forwarding, and the Handover Request message further includes a SAE bearer context.
The SAE bearer context includes Transport Network Layer (TNL) information of the S-GW for transmitting upper layer data, QoS information born by SAE, etc.
In step 405 , the T_eNB performs an admission control procedure based on the received QoS information born by SAE.
In step 406 , the T_eNB sends a Handover Request Acknowledge message to the S_eNB while preparing the handover resource.
The Handover Request Acknowledge message includes a Tunnel End Point Identifier (TEID) and an address of TNL supporting DL/UL data forwarding allocated by the T_eNB.
In step 407 , the S_eNB sends a Handover Command message to the UE to instruct the UE to perform handover on receiving the Handover Request Acknowledge message from the T_eNB.
The Handover Command message includes a new Radio Network Temporary Identity (RNTI), a possible starting time, a System Information Block (SIB) of the T_eNB, etc.
On receiving the Handover Command message from the S_eNB, the UE ceases sending PDCP-SDUs to the S_eNB. The UE may utilize a Radio Link Control (RLC) Acknowledge procedure or other mechanisms to ensure proper reception of the Handover Command message.
After sending the Handover Command message, the S_eNB commences performing the UL/DL data forwarding, i.e., buffers the PDCP-SDUs received from the UE in the Buffer and sends the PDCP-SDUs to the T_eNB.
In step 408 , the S_eNB sends a “PDCP-SN report” to the T_eNB via an X2 interface to inform the T_eNB of SNs of all received PDCP-SDUs on receiving the RLC layer Acknowledge message in response to the Handover Command message or after the S_eNB waits for a period of time in case of receiving no RLC layer Acknowledge message.
The above-mentioned period of time in case of receiving no RLC layer Acknowledge message depends on the possible starting time of the Handover Command message.
In step 409 , the UE sends a Synchronization message to the T_eNB to request synchronization with the T_eNB once the possible starting time of the Handover Command message arrives. Then, the T_eNB begins to obtain the time advance of the UE.
In step 410 , after the UE is synchronized with the T_eNB, the T_eNB sends to the UE a Synchronization Reply message including UL resource allocation information, the time advance, the PDCP-SNs of the PDCP-SN report, etc.
The T_eNB may possibly not receive the PDCP-SN report from the S_eNB in time due to the delay of the X2 interface after the UE is synchronized with the T_eNB. If the T_eNB has not received the PDCP-SN report when replying to the UE, the Synchronization Reply message does not include the PDCP-SNs; otherwise the Synchronization Reply message includes the PDCP-SNs.
The UE discards corresponding PDCPs from the re-transmission queue according to the indication of PDCP-SNs for the purpose of saving rare resource of the air interface. The UE proceeds as the prior art in case of no PDCP-SNs. It can be seen that the solution according to the present invention is easy to be compatible with the prior art.
In step 411 , the UE sends a Handover Confirm message to the T_eNB after the UE accesses the target cell successfully, to inform of the completion of handover procedure.
Therefore, the present invention emphasizes on addition of step 408 , modification to step 410 , and subsequent re-transmission of PDCPs at the UE.
FIG. 5 is a flowchart of the first embodiment, in which:
In step 501 , after the S_eNB sends the Handover Command message to the UE, the S_eNB sends a PDCP-SN report to the T_eNB on receiving an RLC Acknowledge message or after the S_eNB waits for a period of time.
In step 502 , it is determined whether the T_eNB has received the PDCP-SN report from the S_eNB after the UE synchronizes with the T_eNB. The branch of step 503 is executed if the T_eNB has received the PDCP-SN report from the S_eNB. The branch of step 505 is executed if the T_eNB has not received the PDCP-SN report from the S_eNB.
In step 503 , the T_eNB sends a Synchronization Reply message carrying PDCP-SNs to the UE.
In step 504 , the UE discards PDCP SDUs corresponding to the PDCP-SNs from a PDCP re-transmission queue in which corresponding ACKs are not received, and re-transmits only the rest of PDCP-SDUs in the re-transmission queue to the T_eNB.
In step 505 , the T_eNB sends a Synchronization Reply message to the UE. Being the same as that in the conventional solution, the Synchronization Reply message includes UL resource allocation information and a time advance.
In step 506 , the UE re-transmits to the T_eNB all PDCP-SDUs whose ACKs are not received.
With the present invention, insignificant re-transmission of PDCP-SDUs from the UE to the T_eNB can be avoided.
Also taking the scenario as illustrated in FIG. 3 as an example, the UE sends data a, b, c and d to the S_eNB, however, the data b fails during transmission, and the UE does not receive any ACK to the data b according. The S_eNB receives only the data a, c and d, and the data c and d becomes disordered. It is assumed that the UE does not receive any ACK to the data c and d. According to the solution of this embodiment, the S_eNB adds a step of assembling the PDCP-SDU SN report for the received PDCP-SDUs based on the conventional procedure. The PDCP-SDU SN report includes SNs of the data a, c and d. The
S_eNB delivers the PDCP-SDU SN report to the T_eNB at an appropriate time (on receiving the RLC Acknowledge message, or after the S_eNB waits for a period of time). The T_eNB informs the UE that which PDCP-SDUs have been received by the S_eNB successfully through a Synchronization Reply message, i.e., the data a, c and d has been received, which need not to be re-transmitted. The UE receives only an ACK to the data a, and puts the data b, c and d to the re-transmission queue for re-transmission. However, the UE discards the data c and d from the re-transmission queue because the UE knows from the Synchronization Reply message that the data c and d has been received by the S_eNB. That is, the UE re-transmits only the failed data b to the T_eNB. Compared with the conventional solution, re-transmission of the data c and d (the S_eNB forwards the data c and d to the T_eNB by data forwarding) can be avoided, saving precious radio resource of the air interface. A diagram of processing the scenario of FIG. 3 by using this embodiment is illustrated in FIG. 6 .
The second embodiment of the method according to the present invention is described hereinafter.
In the above first embodiment, the T_eNB sends a Reply message including no PDCP-SDU SN to the UE in a conventional manner after the synchronization of the UE in case of receiving no PDCP-SDU SN. In contrast, the T_eNB sends a Reply message to the UE after receiving PDCP-SDU SNs within a preset period of time in the second embodiment, delivering the PDCP-SDU SNs to the UE as far as possible and ensuring no re-transmission of redundant PDCP-SDUs from the UE.
FIG. 7 is a flowchart of the second embodiment, in which:
In step 701 , after the S_eNB sends a Handover Command message to the UE, the S_eNB sends a PDCP-SDU SN report to the T_eNB on receiving an RLC Acknowledge message or after the S_eNB waits for a period of time.
In step 702 , it is determined whether the T_eNB has received the PDCP-SDU SN report from the S_eNB after the UE is synchronized with the T_eNB. The branch of step 703 is executed if the T_eNB has received the PDCP-SDU SN report from the S_eNB. The branch of step 705 is executed if the T_eNB has not received the PDCP-SDU SN report from the S_eNB.
In step 703 , the T_eNB sends a Synchronization Reply message carrying PDCP-SDU SNs to the UE.
In step 704 , the UE discards PDCP-SDUs corresponding to the PDCP-SDU SNs from the PDCP re-transmission queue in which corresponding ACKs are not received, and re-transmits only the rest of PDCP-SDUs in the re-transmission queue to the T_eNB.
In step 705 , it is determined whether the PDCP-SN report is received within a preset period of time. Step 703 is executed if the PDCP-SN report is received within a preset period of time. Step 706 is executed if the waiting time exceeds the period of time.
There is a plurality of reasons for failing to receive the PDCP-SN report, such as the delay of the X2 interface, or the network transmission congestion, or improper parsing of the received PDCP-SDU SNs at the T_eNB, in this case, step 706 is executed.
In step 706 , the T_eNB sends a Synchronization Reply message to the UE. As being the same as that in the conventional solution, the Synchronization Reply message includes only UL resource allocation information and a time advance.
In step 707 , the UE re-transmits all PDCP-SDUs whose ACKs are not received to the T_eNB.
Based on the first embodiment, the T_eNB does not send the Synchronization Reply message immediately in case of not receiving the PDCP-SDU SN report but waits for a period of time according to the second embodiment, further ensuring the reception of the Synchronization Reply message including PDCP-SDU SNs and further effectively ensuring saving of radio resource.
The third embodiment of the present invention is described hereinafter.
The third embodiment differs from the above two embodiments in that the processing of T_eNB after step 408 . In the third embodiment, the T_eNB carries the PDCP-SDU SNs in the Reply message to the UE if the T_eNB has received the PDCP-SDU SN report from the S_eNB before the synchronization of UE. The T_eNB does not carry the PDCP-SDU SNs in the Reply message to the UE if the T_eNB has not received the PDCP-SDU SN report from the S_eNB after the synchronization of UE, but sends an RRC message, an RLC message or a MAC message to the UE carrying the PDCP-SDU SNs immediately once the T_eNB receives the PDCP-SDU SN report. Accordingly, the UE discards PDCP-SDUs corresponding to the PDCP-SDU SNs carried in the RRC message, the RLC message or the MAC message from the re-transmission queue, and re-transmits the rest of PDCP-SDUs of the queue to the T_eNB.
FIG. 8 is flowchart of the third embodiment, in which:
In step 801 , after the S_eNB sends a Handover Command message to the UE, the S_eNB sends a PDCP-SDU SN report to the T_eNB on receiving an RLC Acknowledge message or after the S_eNB waits for a period of time.
In step 802 , it is determined whether the T_eNB has received the PDCP-SDU SN report sent from the S_eNB after the UE is synchronized with the T_eNB. The branch of step 803 is executed if the T_eNB has received the PDCP-SDU SN report sent from the S_eNB, otherwise the branch of step 805 is executed.
In step 803 , the T_eNB sends to the UE a Synchronizaiton Reply message carrying PDCP-SDU SNs.
In step 804 , the UE discards PDCP-SDUs corresponding to the PDCP-SDU SNs from the PDCP-SDU re-transmission queue in which corresponding ACKs are not received, and re-transmits only the rest of PDCP-SDUs in the re-transmission queue to the T_eNB.
In step 805 , the T_eNB sends a Synchronization Reply message to the UE. As being the same as that in the conventional solution, the Synchronization Reply message includes only UL resource allocation information and a time advance.
In step 806 , the T_eNB receives the PDCP-SDU SN report sent from the S_eNB.
In step 807 , the T_eNB sends to the UE an RRC message, an RLC message or a MAC message carrying the PDCP-SDU SNs immediately.
In step 808 , the UE discards PDCP-SDUs corresponding to the PDCP-SDU SNs carried in the RRC message, the RLC message or the MAC message from the re-transmission queue, and re-transmits only the rest of PDCP-SDUs in the queue to the T_eNB.
In this embodiment, the T_eNB still sends the Synchronization Reply message to the UE in the prior art in case of receiving no PDCP-SN report, which is well compatible with the prior art. The T_eNB sends to the UE the RRC message, the RLC message or the MAC message immediately so that the possibility of re-transmitting redundant PDCP-SDUs is reduced to the least extent, ensuring effective and reasonable utilization of radio resource.
A diagram of a structure of an S_eNB according to the present invention is illustrated in FIG. 9 . Besides an X2 interface unit 901 communicated with the T_eNB and a UE interface unit 902 communicated with the UE, the S_eNB includes a report assembling unit 903 .
The report assembling unit 903 is mainly responsible for assembling a PDCP-SDU SN report including SNs of PDCP-SDUs received at the UE interface unit 902 . The PDCP-SDU SN report is sent to the T_eNB at an appropriate time (on receiving an RLC Acknowledge message, or after the report assembling unit 903 waits for a period of time) via the X2 interface unit 901 .
A diagram of a structure of a T_eNB according to the present invention is illustrated in FIG. 10 . Besides an X2 interface unit 1001 communicated with the S_eNB and a UE interface unit 1002 communicated with the UE, the T_eNB includes a message assembling unit 1003 .
The message assembling unit 1003 is mainly responsible for assembling a message including the PDCP-SDU SNs received at the S_eNB. Based on the functions of respective units of the conventional T_eNB, the X2 interface unit 1001 is further adapted to receive the PDCP-SDU SN report sent from the S_eNB, the report including the PDCP-SDU SNs received at the S_eNB. The UE interface unit 1002 is further adapted to send the message assembled by the message assembling unit 1003 to the UE. The message assembled by the message assembling unit 1003 may be a Synchronization Reply message, an RRC message, an RLC message, or a MAC message.
A diagram of a structure of a UE according to the present invention is illustrated in FIG. 11 . Besides an eNB interface unit 1101 communicated with the S_eNB or the T_eNB and a re-transmission queue 1102 in which PDCP-SDUs are buffered, the UE includes a message parsing unit 1103 and a queue adjustment unit 1104 .
Based on conventional functions, the eNB interface unit 1101 is further adapted to receive from the T_eNB a message indicating PDCP-SDU SNs that have been received by the S_eNB. The message parsing unit 1103 is mainly responsible for parsing the message to obtain the PDCP-SDU SNs that have been received by the S_eNB. The queue adjustment unit 1104 is mainly responsible for discarding the PDCP-SDU SNs that have been received by the S_eNB from the re-transmission queue 1102 . Accordingly, the eNB interface unit 1101 re-transmits the rest of PDCP-SDUs in the re-transmission queue 1102 to the T_eNB. The message indicating the PDCP-SDU SNs that have been received by the S_eNB may be a Synchronization Reply message, an RRC message, an RLC message, or a MAC message.
Reference can be made to the aforementioned method embodiments for specific implementations of the S_eNB, the T_eNB and the UE according to the present invention, which is not repeated here.
The above description is merely for preferred embodiments of the present invention. It should be noted that an ordinary skill in the art without departing from the scope of the present invention can make a plurality of changes and modifications, which shall be encompassed in the protection scope of the present invention. | A method and device for indicating data re-transmission when area switching in LTE system, wherein the method comprises the following steps: S_eNB sends PDCP-SDU CN report to T_eNB in order to announce PDCP-SDU SN received, and T_eNB announces PDCP-SDU SN received by S_eNB to UE. Thereby, UE would not re-transmit PDCP-SDU corresponding to received SN, which avoids re-transmission of useless PDCP-SDU, and saves radio resources comparing with prior solutions. | Briefly summarize the invention's components and working principles as described in the document. | [
"The present application claims priority to Chinese Patent Application No. 200710121647.",
"X, entitled “METHOD FOR DATA RE-TRANSMISSION DURING CELL HANDOVER IN LTE SYSTEM AND APPARATUS THEREOF”, filed with Chinese Patent Office on Sep. 11, 2007, which is incorporated herein in its entirety.",
"FIELD OF THE INVENTION The present invention relates to the technical field of the Long Time Evolution (LTE) system in mobile communications, and particularly to a method for indicating data re-transmission during cell handover in the LTE system and a device thereof.",
"BACKGROUND OF THE INVENTION During the cell handover in the LTE system, the idea of User Equipment (UE) assistant to network control, i.e., the steps of “measure-report-decide-execute”, is still adopted.",
"When the Source Evolved Node B (S_eNB) decides that the UE shall handover to the Target Evolved Node B (T_eNB) according to measurement reports from the UE and the T_eNB, the S_eNB exchanges information with the T_eNB directly via an X2 interface, to complete resource preparation in the target cell;",
"then, the S_eNB instructs the UE to handover to the target cell;",
"after a successful handover, the T_eNB informs the S_eNB to release radio resource of the original cell.",
"In addition, the S_eNB transmits data that is not transmitted yet to the T_eNB and updates relation of nodes between a user plane and a control plane.",
"Referring to FIG. 1 , a flowchart of cell handover in the LTE system in the prior art mainly includes: [1] The S_eNB configures the UE with a measurement procedure;",
"[2] The UE sends a measurement report to the S_eNB;",
"[3] The S_eNB makes a UE handover decision according to the measurement report and Radio Resource Management (RRM) information;",
"[4] The S_eNB sends a handover request to the T_eNB;",
"[5] On receiving the handover request from the S_eNB, the T_eNB performs an admission control procedure according to the received E-RAB Quality of Service (QoS) information;",
"[6] The T_eNB sends a Handover Request Acknowledge message to the S_eNB;",
"[7] The S_eNB sends a Handover Command message to the UE, to instruct the UE to perform a handover;",
"[8] The UE sends a Synchronization message to the T_eNB;",
"[9] The T_eNB feeds a Synchronization Reply message back to the UE, the Synchronization Reply message including UL resource allocation information, a time advance, etc.",
"[10] The UE sends a Handover Complete Acknowledge message to the T_eNB after the UE accesses the target cell successfully.",
"On the user plane, in order to avoid loss of uplink data from the UE and to maintain ordered transmission of the uplink data during the handover, an uplink data forwarding solution is adopted, which is performed between step [7] and step [8] of FIG. 1 (as illustrated by dotted lines).",
"Generally, the data forwarding refers to that: the S_eNB forwards received disordered Packet Data Convergence Protocol-Service Data Units (PDCP-SDUs) to the T_eNB, and the PDCP-SDUs are attached with Sequence Numbers (SNs), then the T_eNB sends the received PDCP-SDUs to the Service Gateway (S-GW).",
"During the handover, ordered transmission of upper layer PDUs is based on continuous PDCP-SNs and a re-order function provided by the PDCP layer.",
"In the uplink, the re-order function of the PDCP layer of the T_eNB ensures the ordered transmission of the uplink PDCP-SDUs.",
"In the present LTE system, the air interface is based on the Automatic Repeat Request/Hybrid Automatic Repeat Request (ARQ/HARQ) mechanism.",
"The S_eNB feeds ACKs back to the UE on successfully receiving ordered PDCP-SDUs.",
"The UE re-transmits to the T_eNB those PDCP-SDUs whose ACKs are not received at the UE.",
"It is not difficult to understand that the UE does not receive any ACK to a PDCP in two cases: in the first case, the S_eNB does not receive the PDCPs due to reasons such as network, etc.",
", and does not feed ACKs back to the UE accordingly;",
"in the second case, the S_eNB has received ordered PDCPs successfully, however, ACKs are not fed back to the UE successfully due to network reasons.",
"The above second case may result in insignificant re-transmission from the UE to the T_eNB and a waste of precious radio resource.",
"Examples are described hereinafter with reference to the two cases.",
"FIG. 2 illustrates a fact in which re-transmission of PDCP-SDUs from the UE results in an insignificant waste.",
"The S_eNB receives data 1 , 2 and 3 from the UE successfully and transmits the data 1 , 2 and 3 to the S-GW via an S1 interface.",
"It is assumed that the UE receives only an ACK to the data 1 fed back from the network side and does not receive ACKs to the data 2 and 3 .",
"In this case, the UE continues to send the data 2 and 3 to the T_eNB, the T_eNB receives the data 2 and 3 and sends the re-transmitted data 2 and 3 to the S-GW, which results in reception of repeated data in the Evolved Packet Core (EPC) system and a waste of precious radio resource at the air interface.",
"FIG. 3 illustrates another fact in which re-transmission of PDCP-SDUs from the UE results in an insignificant waste.",
"The UE sends data a, b, c and d to the S_eNB, however, the data b fails during transmission and the S_eNB receives only the data a, c and d, and the data c and d becomes disordered.",
"According to the conventional solution of data forwarding, the S_eNB sends the ordered data a to the S-GW, buffers the disordered data c and d in a buffer, and then sends the data c and d to the T_eNB which delivers the data c and d to the S-GW.",
"It is assumed that the UE does not receive any ACK to the data c and d. In this case, the UE receives only an ACK to the data a, and re-transmits the data b, c and d to the T_eNB because the UE does not receive any ACK to the data b, c and d. Apparently, the data c and d is re-transmitted.",
"On one hand, the S_eNB sends the buffered data c and d to the T_eNB;",
"on the other hand, the UE re-transmits the data c and d to the T_eNB due to no reception of any ACK, thereby resulting in a waste of resource.",
"SUMMARY OF THE INVENTION In view of this, the present invention provides a method for indicating data re-transmission during cell handover in a Long Time Evolution (LTE) system, so as to solve the problem of waste of radio resource due to re-transmission of redundant PDCP-SDUs in the conventional solution.",
"Corresponding to the method, the present invention further provides a device for indicating data re-transmission during cell handover in a Long Time Evolution (LTE) system, i.e., an eNB, and a UE.",
"The technical solution of the present invention is described as follows: A method for indicating data re-transmission during cell handover in a Long Time Evolution (LTE) system includes: sending, by a Source Evolved Node B (S_eNB), a Packet Data Convergence Protocol-Service Data Unit Sequence Number (PDCP-SDU SN) report to a Target Evolved Node B (T_eNB), for informing of PDCP-SDU SNs that have been received by the S_eNB;",
"and informing, by the T_eNB, User Equipment (UE) the PDCP-SDU SNs that have been received by the S_eNB.",
"The method further includes: discarding, by the UE, PDCP-SDUs that have been received by the S_eNB from a re-transmission queue according to the received PDCP-SDU SNs, and re-transmitting only the rest of PDCP-SDUs in the queue to the T_eNB.",
"The T_eNB informs the UE of the PDCP-SDU SNs received by the S_eNB through a synchronization reply message, a Radio Resource Control (RRC) message, a Radio Link Control (RLC) message or a Media Access Control (MAC) message.",
"Preferably, after the UE is synchronized with the T_eNB, the T_eNB determines whether the T_eNB has received the PDCP-SDU SN report;",
"the T_eNB sends to the UE the synchronization reply message carrying the PDCP-SDU SNs that have been received by the S_eNB if the T_eNB has received the PDCP-SDU SN report;",
"and the T_eNB sends to the UE the synchronization reply message carrying no PDCP-SDU SN if the T_eNB has not received the PDCP-SDU SN report.",
"Or, after the UE is synchronized with the T_eNB, the T_eNB determines whether the T_eNB has received the PDCP-SDU SN report;",
"the T_eNB sends to the UE the synchronization reply message carrying the PDCP-SDU SNs that have been received by the S_eNB if the T_eNB has received the PDCP-SDU SN report;",
"and if the T_eNB has not received the PDCP-SDU SN report, the T_eNB waits for a preset period of time, and sends to the UE the synchronization reply message carrying no PDCP-SDU SN if the T_eNB does not receive the PDCP-SDU SN report within the preset period of time;",
"and the T_eNB sends to the UE the synchronization reply message carrying the PDCP-SDU SNs that have been received by the S_eNB if the T_eNB receives the PDCP-SDU SN report within the preset period of time.",
"Or, after the UE is synchronized with the T_eNB, the T_eNB determines whether the T_eNB has received the PDCP-SDU SN report;",
"the T_eNB sends to the UE the synchronization reply message carrying the PDCP-SDU SNs that have been received by the S_eNB if the T_eNB has received the PDCP-SDU SN report;",
"and if the T_eNB has not received the PDCP-SDU SN report, the T_eNB sends to the UE the synchronization reply message carrying no PDCP-SDU SN;",
"and the T_eNB sends to the UE the RRC message, the RLC message or the MAC message immediately to inform the UE of the PDCP-SDU SNs that have been received by the S_eNB.",
"The time when the S_eNB sends the PDCP-SDU SN report to the T_eNB is when the S_eNB receives an acknowledge message to a handover command message fed back from the UE, or when a preset time arrives from the time of sending the handover command message from the UE if the S_eNB does not receive any acknowledge message to the handover command message.",
"An Evolved Node B (eNB) for indicating data re-transmission during cell handover in a Long Time Evolution (LTE) system includes: an X2 interface unit, a User Equipment (UE) interface unit communicated with UE, where the eNB further includes: a report assembling unit and a message assembling unit;",
"the report assembling unit is adapted to assemble a Packet Data Convergence Protocol-Service Data Unit Sequence Number (PDCP-SDU SN) report including SNs of PDCP-SDUs received at the UE interface, the report being sent to the T_eNB via the X2 interface unit;",
"the message assembling unit is adapted to assemble a message including PDCP-SDU SNs that have been received at the S_eNB according to the PDCP-SDU SN report received at the X2 interface unit, and send the message to the UE via the UE interface unit.",
"The message assembled by the message assembling unit is a synchronization reply message, a Radio Resource Control (RRC) message, a Radio Link Control (RLC) message or a Media Access Control (MAC) message.",
"A User Equipment (UE) for controlling data re-transmission during cell handover in a Long Time Evolution (LTE) system includes: an Evolved Node B (eNB) interface unit communicated with a Source Evolved Node B (S_eNB) or a Target Evolved Node B (T_eNB) and a re-transmission queue in which Packet Data Convergence Protocol-Service Data Units (PDCP-SDUs) are buffered, where the UE further includes: a message parsing unit and a queue adjustment unit;",
"where the eNB interface unit is adapted to receive from the T_eNB a message indicating PDCP-SDU Sequence Numbers (SNs) that have been received by the S_eNB;",
"the message parsing unit is adapted to parse the message to obtain the PDCP-SDU SNs that have been received by the S_eNB;",
"the queue adjustment unit is adapted to discard the PDCP-SDU SNs that have been received by the S_eNB from the re-transmission queue, and the eNB interface unit re-transmits the rest of PDCP-SDUs in the re-transmission queue to the T_eNB.",
"The message indicating PDCP-SDU SNs that have been received by the S_eNB is a synchronization reply message, a Radio Resource Control (RRC) message, a Radio Link Control (RLC) message or a Media Access Control (MAC) message.",
"The above technical solution includes the following technical effects: In the solution of cell handover in the LTE system according to the prior art, the UE re-transmits a PDCP to the T_eNB if only the UE does not receive an ACK to the PDCP.",
"However, in the present invention, the UE further determines whether the UE has received from the T_eNB a PDCP-SN indicating that the S_eNB has received the PDCP.",
"If the UE does not receive the ACK to the PDCP but receives the PDCP-SN indicating that the S_eNB has received the PDCP, the UE does not re-transmit the PDCP, thereby avoiding re-transmission of redundant PDCPs and resulting in effective saving of radio resource compared with the conventional solution.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of cell handover in the LTE system in the prior art;",
"FIG. 2 is a first diagram of resending data from the UE in the prior art;",
"FIG. 3 is a second diagram of resending data from the UE in the prior art;",
"FIG. 4 is a diagram of a first embodiment of the method according to the present invention;",
"FIG. 5 is a flowchart of the first embodiment of the method according to the present invention;",
"FIG. 6 is an exemplary diagram of the first embodiment of the method according to the present invention;",
"FIG. 7 is a flowchart of a second embodiment of the method according to the present invention;",
"FIG. 8 is a flowchart of a third embodiment of the method according to the present invention;",
"FIG. 9 is a diagram of a structure of an S_eNB device according to the present invention;",
"FIG. 10 is a diagram of a structure of a T_eNB device according to the present invention;",
"and FIG. 11 is a diagram of a structure of a UE device according to the present invention.",
"DETAILED DESCRIPTION OF THE INVENTION The core of the present invention lies in that a process is added during cell handover of the UE, i.e., the S_eNB informs the UE via the T_eNB that which PDCP-SDUs have been received by the S_eNB successfully and the UE does not need to re-transmit the PDCP-SDUs even if the UE does not receive ACKs to the PDCP-SDUs.",
"Further, the present invention is implemented in the following manner: 1] The S_eNB sends a PDCP-SDU SN report to the T_eNB, to inform the T_eNB of PDCP-SDU SNs (including SNs of all ordered and unordered PDCP-SDUs) that have been received by the S_eNB;",
"2] The T_eNB re-transmits the PDCP-SDU SNs to the UE according to the report, to inform the UE which PDCP-SDUs have been received;",
"3] The UE does not re-transmit the PDCP-SDUs according to the received PDCP-SDU SNs.",
"In the solution of cell handover in the LTE system in the prior art, the UE re-transmits a PDCP-SDU to the T_eNB if only the UE does not receive an ACK to the PDCP-SDU.",
"However, in the present invention, the UE further determines whether the UE has received from the T_eNB the SN indicating that the S_eNB has received the PDCP-SDU.",
"If the UE does not receive an ACK to a PDCP-SDU but receives a PDCP-SDU SN indicating reception of the PDCP-SDU, the UE does not re-transmit the PDCP-SDU, thereby avoiding re-transmission of duplicate PDCP-SDU and resulting in effective saving of radio resource compared with the conventional solution.",
"Embodiments of the present invention are described in detail hereinafter with reference to the accompanying drawings.",
"It is not difficult to understand that a signaling is added in cell handover according to the present invention, so as to transmit the PDCP-SDU SNs that have been received by the S_eNB.",
"The UE does not re-transmit the PDCP-SDUs.",
"In order to make the whole procedure more clear, the procedure of cell handover in the LTE system, i.e., a modified solution based on the cell handover described in the background of the invention, is described hereinafter.",
"FIG. 4 is a diagram of cell handover in the LTE system according to the first embodiment.",
"The cell handover includes the following steps: In step 401 , the S_eNB configures the UE with a measurement procedure according to roaming restriction information.",
"The measurement information provided by the S_eNB may be of assistance to control the connection mobility function of the UE.",
"In step 402 , the UE sends a measurement report to the S_eNB.",
"In step 403 , the S_eNB makes a handover decision to perform cell handover of the UE according to the measurement report from the UE and RRM information.",
"In step 404 , the S_eNB sends to the T_eNB a Handover Request message carrying necessary information so that the T_eNB prepares handover resource.",
"The Handover Request message also indicates whether the system supports DL/UL data forwarding, and the Handover Request message further includes a SAE bearer context.",
"The SAE bearer context includes Transport Network Layer (TNL) information of the S-GW for transmitting upper layer data, QoS information born by SAE, etc.",
"In step 405 , the T_eNB performs an admission control procedure based on the received QoS information born by SAE.",
"In step 406 , the T_eNB sends a Handover Request Acknowledge message to the S_eNB while preparing the handover resource.",
"The Handover Request Acknowledge message includes a Tunnel End Point Identifier (TEID) and an address of TNL supporting DL/UL data forwarding allocated by the T_eNB.",
"In step 407 , the S_eNB sends a Handover Command message to the UE to instruct the UE to perform handover on receiving the Handover Request Acknowledge message from the T_eNB.",
"The Handover Command message includes a new Radio Network Temporary Identity (RNTI), a possible starting time, a System Information Block (SIB) of the T_eNB, etc.",
"On receiving the Handover Command message from the S_eNB, the UE ceases sending PDCP-SDUs to the S_eNB.",
"The UE may utilize a Radio Link Control (RLC) Acknowledge procedure or other mechanisms to ensure proper reception of the Handover Command message.",
"After sending the Handover Command message, the S_eNB commences performing the UL/DL data forwarding, i.e., buffers the PDCP-SDUs received from the UE in the Buffer and sends the PDCP-SDUs to the T_eNB.",
"In step 408 , the S_eNB sends a “PDCP-SN report”",
"to the T_eNB via an X2 interface to inform the T_eNB of SNs of all received PDCP-SDUs on receiving the RLC layer Acknowledge message in response to the Handover Command message or after the S_eNB waits for a period of time in case of receiving no RLC layer Acknowledge message.",
"The above-mentioned period of time in case of receiving no RLC layer Acknowledge message depends on the possible starting time of the Handover Command message.",
"In step 409 , the UE sends a Synchronization message to the T_eNB to request synchronization with the T_eNB once the possible starting time of the Handover Command message arrives.",
"Then, the T_eNB begins to obtain the time advance of the UE.",
"In step 410 , after the UE is synchronized with the T_eNB, the T_eNB sends to the UE a Synchronization Reply message including UL resource allocation information, the time advance, the PDCP-SNs of the PDCP-SN report, etc.",
"The T_eNB may possibly not receive the PDCP-SN report from the S_eNB in time due to the delay of the X2 interface after the UE is synchronized with the T_eNB.",
"If the T_eNB has not received the PDCP-SN report when replying to the UE, the Synchronization Reply message does not include the PDCP-SNs;",
"otherwise the Synchronization Reply message includes the PDCP-SNs.",
"The UE discards corresponding PDCPs from the re-transmission queue according to the indication of PDCP-SNs for the purpose of saving rare resource of the air interface.",
"The UE proceeds as the prior art in case of no PDCP-SNs.",
"It can be seen that the solution according to the present invention is easy to be compatible with the prior art.",
"In step 411 , the UE sends a Handover Confirm message to the T_eNB after the UE accesses the target cell successfully, to inform of the completion of handover procedure.",
"Therefore, the present invention emphasizes on addition of step 408 , modification to step 410 , and subsequent re-transmission of PDCPs at the UE.",
"FIG. 5 is a flowchart of the first embodiment, in which: In step 501 , after the S_eNB sends the Handover Command message to the UE, the S_eNB sends a PDCP-SN report to the T_eNB on receiving an RLC Acknowledge message or after the S_eNB waits for a period of time.",
"In step 502 , it is determined whether the T_eNB has received the PDCP-SN report from the S_eNB after the UE synchronizes with the T_eNB.",
"The branch of step 503 is executed if the T_eNB has received the PDCP-SN report from the S_eNB.",
"The branch of step 505 is executed if the T_eNB has not received the PDCP-SN report from the S_eNB.",
"In step 503 , the T_eNB sends a Synchronization Reply message carrying PDCP-SNs to the UE.",
"In step 504 , the UE discards PDCP SDUs corresponding to the PDCP-SNs from a PDCP re-transmission queue in which corresponding ACKs are not received, and re-transmits only the rest of PDCP-SDUs in the re-transmission queue to the T_eNB.",
"In step 505 , the T_eNB sends a Synchronization Reply message to the UE.",
"Being the same as that in the conventional solution, the Synchronization Reply message includes UL resource allocation information and a time advance.",
"In step 506 , the UE re-transmits to the T_eNB all PDCP-SDUs whose ACKs are not received.",
"With the present invention, insignificant re-transmission of PDCP-SDUs from the UE to the T_eNB can be avoided.",
"Also taking the scenario as illustrated in FIG. 3 as an example, the UE sends data a, b, c and d to the S_eNB, however, the data b fails during transmission, and the UE does not receive any ACK to the data b according.",
"The S_eNB receives only the data a, c and d, and the data c and d becomes disordered.",
"It is assumed that the UE does not receive any ACK to the data c and d. According to the solution of this embodiment, the S_eNB adds a step of assembling the PDCP-SDU SN report for the received PDCP-SDUs based on the conventional procedure.",
"The PDCP-SDU SN report includes SNs of the data a, c and d. The S_eNB delivers the PDCP-SDU SN report to the T_eNB at an appropriate time (on receiving the RLC Acknowledge message, or after the S_eNB waits for a period of time).",
"The T_eNB informs the UE that which PDCP-SDUs have been received by the S_eNB successfully through a Synchronization Reply message, i.e., the data a, c and d has been received, which need not to be re-transmitted.",
"The UE receives only an ACK to the data a, and puts the data b, c and d to the re-transmission queue for re-transmission.",
"However, the UE discards the data c and d from the re-transmission queue because the UE knows from the Synchronization Reply message that the data c and d has been received by the S_eNB.",
"That is, the UE re-transmits only the failed data b to the T_eNB.",
"Compared with the conventional solution, re-transmission of the data c and d (the S_eNB forwards the data c and d to the T_eNB by data forwarding) can be avoided, saving precious radio resource of the air interface.",
"A diagram of processing the scenario of FIG. 3 by using this embodiment is illustrated in FIG. 6 .",
"The second embodiment of the method according to the present invention is described hereinafter.",
"In the above first embodiment, the T_eNB sends a Reply message including no PDCP-SDU SN to the UE in a conventional manner after the synchronization of the UE in case of receiving no PDCP-SDU SN.",
"In contrast, the T_eNB sends a Reply message to the UE after receiving PDCP-SDU SNs within a preset period of time in the second embodiment, delivering the PDCP-SDU SNs to the UE as far as possible and ensuring no re-transmission of redundant PDCP-SDUs from the UE.",
"FIG. 7 is a flowchart of the second embodiment, in which: In step 701 , after the S_eNB sends a Handover Command message to the UE, the S_eNB sends a PDCP-SDU SN report to the T_eNB on receiving an RLC Acknowledge message or after the S_eNB waits for a period of time.",
"In step 702 , it is determined whether the T_eNB has received the PDCP-SDU SN report from the S_eNB after the UE is synchronized with the T_eNB.",
"The branch of step 703 is executed if the T_eNB has received the PDCP-SDU SN report from the S_eNB.",
"The branch of step 705 is executed if the T_eNB has not received the PDCP-SDU SN report from the S_eNB.",
"In step 703 , the T_eNB sends a Synchronization Reply message carrying PDCP-SDU SNs to the UE.",
"In step 704 , the UE discards PDCP-SDUs corresponding to the PDCP-SDU SNs from the PDCP re-transmission queue in which corresponding ACKs are not received, and re-transmits only the rest of PDCP-SDUs in the re-transmission queue to the T_eNB.",
"In step 705 , it is determined whether the PDCP-SN report is received within a preset period of time.",
"Step 703 is executed if the PDCP-SN report is received within a preset period of time.",
"Step 706 is executed if the waiting time exceeds the period of time.",
"There is a plurality of reasons for failing to receive the PDCP-SN report, such as the delay of the X2 interface, or the network transmission congestion, or improper parsing of the received PDCP-SDU SNs at the T_eNB, in this case, step 706 is executed.",
"In step 706 , the T_eNB sends a Synchronization Reply message to the UE.",
"As being the same as that in the conventional solution, the Synchronization Reply message includes only UL resource allocation information and a time advance.",
"In step 707 , the UE re-transmits all PDCP-SDUs whose ACKs are not received to the T_eNB.",
"Based on the first embodiment, the T_eNB does not send the Synchronization Reply message immediately in case of not receiving the PDCP-SDU SN report but waits for a period of time according to the second embodiment, further ensuring the reception of the Synchronization Reply message including PDCP-SDU SNs and further effectively ensuring saving of radio resource.",
"The third embodiment of the present invention is described hereinafter.",
"The third embodiment differs from the above two embodiments in that the processing of T_eNB after step 408 .",
"In the third embodiment, the T_eNB carries the PDCP-SDU SNs in the Reply message to the UE if the T_eNB has received the PDCP-SDU SN report from the S_eNB before the synchronization of UE.",
"The T_eNB does not carry the PDCP-SDU SNs in the Reply message to the UE if the T_eNB has not received the PDCP-SDU SN report from the S_eNB after the synchronization of UE, but sends an RRC message, an RLC message or a MAC message to the UE carrying the PDCP-SDU SNs immediately once the T_eNB receives the PDCP-SDU SN report.",
"Accordingly, the UE discards PDCP-SDUs corresponding to the PDCP-SDU SNs carried in the RRC message, the RLC message or the MAC message from the re-transmission queue, and re-transmits the rest of PDCP-SDUs of the queue to the T_eNB.",
"FIG. 8 is flowchart of the third embodiment, in which: In step 801 , after the S_eNB sends a Handover Command message to the UE, the S_eNB sends a PDCP-SDU SN report to the T_eNB on receiving an RLC Acknowledge message or after the S_eNB waits for a period of time.",
"In step 802 , it is determined whether the T_eNB has received the PDCP-SDU SN report sent from the S_eNB after the UE is synchronized with the T_eNB.",
"The branch of step 803 is executed if the T_eNB has received the PDCP-SDU SN report sent from the S_eNB, otherwise the branch of step 805 is executed.",
"In step 803 , the T_eNB sends to the UE a Synchronizaiton Reply message carrying PDCP-SDU SNs.",
"In step 804 , the UE discards PDCP-SDUs corresponding to the PDCP-SDU SNs from the PDCP-SDU re-transmission queue in which corresponding ACKs are not received, and re-transmits only the rest of PDCP-SDUs in the re-transmission queue to the T_eNB.",
"In step 805 , the T_eNB sends a Synchronization Reply message to the UE.",
"As being the same as that in the conventional solution, the Synchronization Reply message includes only UL resource allocation information and a time advance.",
"In step 806 , the T_eNB receives the PDCP-SDU SN report sent from the S_eNB.",
"In step 807 , the T_eNB sends to the UE an RRC message, an RLC message or a MAC message carrying the PDCP-SDU SNs immediately.",
"In step 808 , the UE discards PDCP-SDUs corresponding to the PDCP-SDU SNs carried in the RRC message, the RLC message or the MAC message from the re-transmission queue, and re-transmits only the rest of PDCP-SDUs in the queue to the T_eNB.",
"In this embodiment, the T_eNB still sends the Synchronization Reply message to the UE in the prior art in case of receiving no PDCP-SN report, which is well compatible with the prior art.",
"The T_eNB sends to the UE the RRC message, the RLC message or the MAC message immediately so that the possibility of re-transmitting redundant PDCP-SDUs is reduced to the least extent, ensuring effective and reasonable utilization of radio resource.",
"A diagram of a structure of an S_eNB according to the present invention is illustrated in FIG. 9 .",
"Besides an X2 interface unit 901 communicated with the T_eNB and a UE interface unit 902 communicated with the UE, the S_eNB includes a report assembling unit 903 .",
"The report assembling unit 903 is mainly responsible for assembling a PDCP-SDU SN report including SNs of PDCP-SDUs received at the UE interface unit 902 .",
"The PDCP-SDU SN report is sent to the T_eNB at an appropriate time (on receiving an RLC Acknowledge message, or after the report assembling unit 903 waits for a period of time) via the X2 interface unit 901 .",
"A diagram of a structure of a T_eNB according to the present invention is illustrated in FIG. 10 .",
"Besides an X2 interface unit 1001 communicated with the S_eNB and a UE interface unit 1002 communicated with the UE, the T_eNB includes a message assembling unit 1003 .",
"The message assembling unit 1003 is mainly responsible for assembling a message including the PDCP-SDU SNs received at the S_eNB.",
"Based on the functions of respective units of the conventional T_eNB, the X2 interface unit 1001 is further adapted to receive the PDCP-SDU SN report sent from the S_eNB, the report including the PDCP-SDU SNs received at the S_eNB.",
"The UE interface unit 1002 is further adapted to send the message assembled by the message assembling unit 1003 to the UE.",
"The message assembled by the message assembling unit 1003 may be a Synchronization Reply message, an RRC message, an RLC message, or a MAC message.",
"A diagram of a structure of a UE according to the present invention is illustrated in FIG. 11 .",
"Besides an eNB interface unit 1101 communicated with the S_eNB or the T_eNB and a re-transmission queue 1102 in which PDCP-SDUs are buffered, the UE includes a message parsing unit 1103 and a queue adjustment unit 1104 .",
"Based on conventional functions, the eNB interface unit 1101 is further adapted to receive from the T_eNB a message indicating PDCP-SDU SNs that have been received by the S_eNB.",
"The message parsing unit 1103 is mainly responsible for parsing the message to obtain the PDCP-SDU SNs that have been received by the S_eNB.",
"The queue adjustment unit 1104 is mainly responsible for discarding the PDCP-SDU SNs that have been received by the S_eNB from the re-transmission queue 1102 .",
"Accordingly, the eNB interface unit 1101 re-transmits the rest of PDCP-SDUs in the re-transmission queue 1102 to the T_eNB.",
"The message indicating the PDCP-SDU SNs that have been received by the S_eNB may be a Synchronization Reply message, an RRC message, an RLC message, or a MAC message.",
"Reference can be made to the aforementioned method embodiments for specific implementations of the S_eNB, the T_eNB and the UE according to the present invention, which is not repeated here.",
"The above description is merely for preferred embodiments of the present invention.",
"It should be noted that an ordinary skill in the art without departing from the scope of the present invention can make a plurality of changes and modifications, which shall be encompassed in the protection scope of the present invention."
] |
CROSS REFERENCE TO RELATED PATENTS
The present application is related to U.S. Pat. No. 4,757,548 (1988) to Fenner, Jr., the disclosure of which is specifically incorporated herein by reference.
FIELD OF INVENTION
The present invention relates generally to transducers capable of converting energy between electrical and mechanical form and, more particularly, to a transducer including a housing having flexible, dome-shaped housing portions capable of elastic deformation.
BACKGROUND OF THE INVENTION
Transducers capable of converting energy between mechanical and electrical form have many varied uses. Transducers operative to convert electrical energy into mechanical energy include conventional speakers as well as transducers capable of generating high energy vibrations.
A brief summary of prior art is listed below.
U.S. Pat. No. 4,757,548 (1988) to Fenner, Jr. discloses a speaker system with a dome-shaped enclosure cooperating with the magnet and voice coil to enhance sound waves in an adjacent solid or liquid.
U.S. Pat. No. 3,524,027 (1970) to Thurston et al. discloses a sound enhancement speaker system having a wall mounted speaker. The speaker has a flat base. The magnets are a toroid and a pair of plates. The voice coil is attached to a flat plate which in turn is attached to a screw mounted in the wall.
U.S. Pat. No. 4,399,334 (1983) to Kakiuchi discloses a headphone speaker having a dome shaped diaphragm to amplify the energy of the voice coil.
U.S. Pat. No. 3,567,870 (1971) to Rivera discloses a wall surface sound transducer having a pair of cup-shaped housing members. The active portions of the vibrating surfaces are flat. A flat plate vibrating surface, however, typically exhibits a narrow frequency band response (500-5000 Hz), and exhibits harmonic distortion due to low damping ratios.
U.S. Pat. No. 4,635,287 (1987) to Hirano discloses a vibrating voice coil plate activated by a magnet mounted on a flat plate or a vibrator.
U.S. Pat. No. 4,179,009 (1979) to Birkner discloses a landspeaker mounting assembly for a resonance panel.
U.S. Pat. No. 4,550,428 (1985) to Yanagishima et al. discloses a car speaker in which part of the chassis of a car is used to form a permanent magnetic field.
U.S. Pat. No. 3,987,258 (1976) to Tsutsui et al. discloses a floatable, water proof sound cabinet.
U.S. Pat. No. 4,187,568 (1980) to McMullan et al. discloses an electromagnetic vibrator mounted in a waterbed.
U.S. Pat. No. Re 23,724 (1953) to Seabert discloses an underwater speaker encased in a heavy casing. The diaphragm of the underwater speaker is immersible in water.
U.S. Pat. No. 4,514,599 (1985) to Yanagishima discloses a car speaker mountable upon a car panel in which the car panel is used as a vibrating panel during operation of the car speaker.
U.S. Pat. No. 4,055,170 (1977) to Nohuwra discloses a chair having a vibrating sheet positioned to be in contact with an occupant seated in the chair. A speaker generates mechanical energy which drives the vibrating seat.
U.S. Pat. No. 4,105,024 (1978) to Raffel discloses a pair of vibrator motors mounted inside a furniture frame.
U.S. Pat. No. 2,778,882 (1957) to Pontzen et al. discloses a microphone with a planar diaphragm having both sides exposed to the air which permits enhanced Short range sensitivity.
U.S. Pat. No. 3,384,719 (1968) to Lanzara discloses a set of speakers mounted in a cushioned headrest.
U.S. Pat. No. 2,115,098 (1938) to Engholm discloses a perforated speaker cover which forms a portion of a diaphragm assembly.
Deutsches Pat. No. 2,745,002 (1978) to Nohmura et al discloses a flat plate vibration generator.
Deutsches Pat. No. 2,115,190 (1972) discloses a waterbed having a pump or a speaker which causes generation of pulsed vibrations.
U.S. Pat. No. 3,524,027 to Thurston et al. teaches a flat, plate-type speaker housing. A toroidal magnet and a flat magnet are mounted on the back panel of the speaker housing. The magnets drive a voice coil which is affixed to a flat diaphragm. A spring acts as a damping device for the diaphragm. As the voice coil forces the diaphragm to vibrate, an equal and opposite force causes the magnets and the back panel of the speaker housing to vibrate. All the resultant vibration is transmitted into a bolt fastened in a wall, and the wall resonates with the induced vibrations.
This flat plate type of transducer, however, exhibits only a limited frequency response (500-5000 Hz) and also exhibits harmonic distortion. Harmonic distortions result in the generation of heat energy caused as a result of oscillations of the voice coil in the magnetic field. This heat energy causes heating of the transducer and reduces the life of the transducer.
U.S. Pat. No. 3,567,870 to Rivera teaches a modification to Thurston et al. wherein the speaker housing is modified to include a pair of cup-shaped members. A damping spring required in Thurston is eliminated, and a flatter (more uniform) and wider frequency response is achieved and a reduction of some harmonic distortion is achieved. However, the front and back vibrating speaker housing members are flat. These flat members cause harmonic distortion.
'548 to Fenner, Jr. achieves a higher frequency response (10-30,000 Hz) by using a dome shaped front speaker housing member. Yet, the back speaker housing member remains flat, thereby causing harmonic distortion. Additional harmonic distortion is created by a flat horizontal support member mounted inside the shell shaped speaker housing.
The present invention eliminates all flat speaker housing members. A pair of symmetrical opposing domes comprise the speaker housing. No support member is utilized. Rather, the magnet(s) are mounted directly on the inside of the back dome member. The dome members are rigid, thereby providing a high damping rate without the use of springs. Other design advantages include flatter frequency responses, crush-resistant deep water high pressure housing, crush-resistant load bearing shock absorbing housing useful as shock absorbers, and vibration sensitivity foe active vibration (phase cancellation) applications.
SUMMARY OF THE INVENTION
The present invention advantageously provides a dual domed vibration transducer which exhibits low levels of harmonic distortion and which exhibits a broad band, flat frequency response.
The present invention further advantageously provides a dual dome transducer housing which exhibits a high damping ratio.
The present invention yet further advantageously provides a dual dome transducer housing which forms a water tight enclosure.
The present invention still further advantageously provides a crush-resistant dual dome transducer housing.
Another object of the present invention is to provide the dual dome housing with adequate torsion stability to withstand use in shock absorber applications.
Yet another object of the present invention is to minimize the size requirements of the dual dome housing as compared to a dome/flat housing design.
Other features of the present invention will become apparent upon reading the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal sectional view of an embodiment of the transducer of the present invention.
FIG. 2 is a top, partial cutaway view of the transducer of FIG. 1.
FIG. 3 is a schematic block diagram of a conventional microphone sensing and speaker nullifying active noise reduction system.
FIG. 4 is a schematic block diagram of an active vibration phase cancellation system of an embodiment of the present invention which includes the transducer shown in FIGS. 1-2 as a portion thereof.
FIG. 5 is a schematic block diagram of an ultrasonic cleaning, vat agitation, and/or non-intrusive level sensing system which includes the transducer shown in FIGS. 1-2 as a portion thereof.
FIG. 6 is a schematic block diagram of a ship-board barnacle prevention, noise cancellation, sound output, and/or hull vibrator system which includes the transducer shown in FIGS. 1-2 as a portion thereof.
FIG. 7 is a sectional view of a hull showing the placement of a plurality of transducers of the system in FIG. 6.
Before explaining the disclosed embodiment of the present invention in detail, it should be noted that it is to be understood that the invention is not limited in its application to the details of the particular arrangements shown in the figures and described in the specification, since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1 a dual dome transducer 100 of an embodiment of the present invention is shown. The transducer is constructed to permit immersion of the transducer 100 in a liquid. The transducer 100 may be mounted to an external structure such as a bulkhead 170, by any of many various types of fasteners including, for example, a T-weld 18, an anchor bolt 13, or a nut and bolt assembly 17.
The transducer 100 includes a permanent magnet assembly 1. The magnet assembly 1 is preferably formed of rare earth materials. A magnetic ceramic material may alternately be used. In the embodiment shown in FIG. 1, the assembly 1 includes a ferrous top washer 2, a ferrous bottom washer 3, and a center pole piece 4. The center pole piece 4 is attached to the ferrous bottom washer 3 by a compression fit with a ring type magnet 5.
The magnet assembly 1 is held together by an appropriate adhesive. The magnet assembly 1 is centered in a bottom dome half 11 forming a portion of the housing of the transducer 100 and is secured in position with a viscous glue 6. An interference fit is formed between the sloped surface 30 of the bottom washer 3 and the viscous glue 6. A raised boss area 7 in the bottom dome 11 supports a female fastening device 8. The device 8 provides for mounting of the transducer to an external structure such as a motor mount. See FIG. 4. The female fastener 8 is held in place by both compression fit and an appropriate adhesive.
The active side of the dual dome transducer 100 is formed a top dome half 10. A raised boss 9 contains a second female fastener 12 used for fastening to bulkhead 170 as shown.
A core 21 is used as a support means for voice coil 22. The core 21 is held in place on raised boss 9 by an appropriate adhesive. The portion of the core 21 about which the voice coil 22 is supported extends into a slot 103 defined by a gap separating the center pole piece 4 from the washer 2 and ring type magnet 5 of the magnet assembly 1. The core 21 extends into the magnet assembly 1, and the coil 22 is suspended at a mid point 200 of the ferrous washer 2 in close proximity to center pole piece 4.
The top dome half 10 of the housing of the transducer 100 is secured about its circumference 26 to the bottom dome half 11 by an appropriate adhesive. The housing of the transducer 100 forms a sealed structure when a water tight strain relief element 23 is used.
A two conductor wire 24 is then connected to the coil wire leads 25 which then pass through water tight strain relief element 23.
Anchor bolt 13 is utilized for attaching the dual dome transducer 100 to wooden objects. The anchor bolt 13 includes threads 14 to permit threaded engagement with the wooden object. The anchor bolt 13 also includes threads 15 to permit threaded engagement with the fastener 12 supported at the top dome half 10 of the housing of the transducer 100. A lock nut 16 is further utilized, to be tightened down onto female fastener 17 to securely tighten the fitting between the bolt 13 and the transducer 100. Nut and bolt assembly 17 may be used for attachment of the transducer 100 to articles. For instance if the transducer is to be bolted to the bulkhead 170, when bolting through the bulkhead 170 is possible, the nut and bolt assembly 17 may be used. As a means for mounting the transducer 100 to metal or fiberglass bulkheads 180, a male fastener 20 may be glued or welded, shown by weld connection 19, to bulkhead 180, thereby forming T-weld 18. Male fasteners 13, 17, and 18 may be used in conjunction with female fasteners 8 and 12 for mounting of the transducer 100 to any article. Optionally a ferro-fluid F positioned in the slot 103 defined by the elements of the magnet assembly 1, such as Ferro-Fluidics L 11®, is held in place by magnetic poles N,S of the magnet assembly 1. This ferro-fluid F increases the power handling capability of the voice coil 22 by up to three times.
In summary the dual dome transducer 100 comprises a top dome half 10, a bottom dome half 11, an inside space 101 defined therebetween, and a speaker assembly 102 having a core 21 affixed to the upper dome half within the inside space 101. In operation the dome halves expand and contract away and towards one another in response to the energy generated during operation of the speaker assembly 102, or in response to induced vibrations.
Referring next to FIG. 2, the transducer 100 is again shown. The distance d1 spanning opposing sides of the transducer is approximately 8 inches. The performance of the transducer 100 duplicates the performance of the prior art '548 Fenner, Jr. device but is of a diameter six inches smaller than the diameter of '548 Fenner Jr. device which is 14 inches in diameter. Dome halves 10, 11 are preferably made of 1/8 inch Lucite Lt®, or a carbon and graphite composite. Core 21 is preferably made of Kapton©. The ring type magnet 5 is preferably made of Neodymium iron boron having a magnetic gauss oerstad (MGO) of up to 54 MGO.
Referring next to FIG. 3 is a phase cancellation system P100, known in the art. A microphone P1 picks up sound S1 which needs to be canceled.
A frequency spectrum analyzer P2 is coupled to receive a signal generated by the microphone P1 and is utilized to sort dominant frequencies of the signal applied thereto. The resulting signal is sent to a frequency matching filter P3. The filter P3 matches the inherent frequency response of the microphone P1 to the inherent frequency response of the loud speaker P7. The resulting signal is passed on to pre-amplifier P4 which increases the signal strength of the signal applied thereto. The signal is then inverted by the signal invertor P5 which provides a signal that is 180° out of phase with the input sound S1. The resulting processed signal is then amplified by amplifier P6, and the amplified processed signal is sent to loud speaker P7. The sound S2 generated by the speaker P7 is 180° out of phase with the input sound S1. The overall effect is a reduction of the sound pressure level of resultant sounds S1, S2.
FIG. 4 illustrates a system 400 incorporating the acoustic transducer 100 to provide vibration phase cancellation using a single transducer 100 as a co-spatial instrument capable of sensing and transmitting vibrations. Thus, the transducer 100 is attached in accordance with previous instruction to the vibrating motor 28 and chassis member 34 where it is desired to reduce the vibration. The sequence begins with an electric current being generated in the voice coil 22 by movement produced by the vibrating motor 28. An electrical input signal representative of electric current generated in the voice coil 22 is applied to a buffer 29 on lines 24 and is stored in buffer 29 for a period of approximately 50 micro seconds or less. The signal is then passed on to a phase invertor 30 and then to preamplifier 33. The phase inverted, preamplified signal is then passed to adjustable gain amplifier 32 where the signal is amplified to match the amplitude of the input signal. The amplified inverted signal is then sent back to acoustic transducer 100 where the electrical energy is converted to physical movement that is 180° out of phase with the vibrations generated by the vibrating motor 28. This provides vibration cancellation.
The switching sequencer 31 is utilized to switch the electrical input signal off to buffer 29 when the amplified signal is sent to transducer 100. Conversely the switching sequencer 31 will switch off the amplified signal while the input signal is being received by the buffer 29. The time span for this sequence has been prescribed to be 50 micro seconds or less in that this is the longest duration of sound that is not detectable by the human sense. The acoustic transducer 100 as described by this invention displays inherent mechanical properties that are necessary for this system 400 to function. Those inherent properties include high damping characteristics that preclude the transducer from resonating or continuing to move after the electronic signal is switched off. By using the single transducer as the sending and receiving device the input frequency and amplitude is directly proportional to the output frequency and amplitude. This matching eliminates the need for complex filtering or equalization between components.
Referring next to FIG. 5 a multi-purpose vat system 500 is shown. Liquid in a tank 51 is energized by vibrations of the transducer 100 mounted upon a sidewall of the tank 51. When the energizing frequency of the vibrations of the transducer 100 (as supplied by a frequency generator 53 and amplified by amplifier 54) is in the ultrasonic range the tank 51 may be used as a container to ultrasonically clean objects 501 inserted into the tank 51. A solvent 502 holds the dirt particles removed during the ultrasonic cleaning process.
A level sensing application is created by varying the frequency of the vibrations generated by the transducer 100 supplied to the tank 51 to determine the natural harmonic resonance of the liquid in the tank. Thereafter, any shift in the resulting output frequency may be interpreted as a change in level of the liquid in the tank. The frequency shift comparator 55 supplies a signal to the linearized output device 56 based on the differential between the determined natural harmonic frequency and the existing frequency which will shift as the level of the liquid in the tank rises or falls. The switching sequencer 57 changes the operating mode from sensing via frequency shift comparator 55 to sending via frequency generator 57. The linearized level signal may then be displayed on a gauge 58.
Another application for the system 500 is to use a high frequency signal as produced by the frequency generator 53 and amplified by amplifier 54. This signal may be used to keep the inside of tank 51 clean.
System components 53-57 may all be incorporated in a solid state chip mounted inside transducer 100.
Referring next to FIGS. 6, 7 a multi-purpose ship-board system 600 is shown. In this system a single high gain acoustic transducer 100 is utilized to provide a multitude of uses. The transducers 100 are rigidly attached to the interior of the hull 71.
The desired hull effect is initiated by the function selector 64. The low frequency generator 65 is utilized to provide a low frequency signal to the amplifier 69. This amplified signal is converted to a physical vibration by the transducer 100. When this low frequency is transmitted through the hull 71, the low frequency physical vibration prevents barnacle formation as is known in the art.
A second application is the vibration phase cancellation network 66, as described previously with respect to FIG. 4. The teaching of FIG. 4 is used to cancel vibrations in the hull 71 that are commonly generated in engineering spaces such as the engine room.
A third application is the recorded media output 67. It is utilized to transmit sound through hull 71 such as the sound image of a school of fish.
A fourth application is the ultrasonic frequency generator 68. It is utilized to create an ultrasonic vibration in the hull 71 which causes a cavitation layer between the hull 71 and the water 711. This cavitation layer reduces the friction coefficient of the hull 71 reducing fuel consumption and increasing speed throughway the water 711.
A fifth application shows the microphone 610 utilized to broadcast verbal messages throughway the hull 71 such as for diver recall.
In all systems the signal is sent to the amplifier 79 and then to the transducers 100. All of the above applications may be used concurrently.
It is known in the art that a configuration of four square magnets could be used to replace the ring type magnet 5. Additionally a cup shaped ferrous metal assembly having a button shaped Neodymium iron boron magnet with a top ferrous metal washer could be used. | A high gain acoustic transducer is formed of a voice coil and a magnetic material housed within a transducer housing. The transducer housing includes two symmetrical dome halves formed of a flexible material. Vibrations of the transducer induce a current in the voice coil as the magnetic material is caused to translate relative to the voice coil. Alternatively, electrical signals applied to the voice coil induce vibrations in the transducer. The voice coil is supported by a first of the two dome halves by way of a first support assembly, and the magnetic material is supported by a second of the two dome halves by way of a second support assembly. The first and second support assemblies are positioned against similarly-dimensioned portions of the first and second dome halves, respectively. Resonating surfaces of the two dome halves are of substantially similar dimensions. The housing forms a watertight enclosure, and the transducer may be utilized in underwater applications. | Summarize the document in concise, focusing on the main idea's functionality and advantages. | [
"CROSS REFERENCE TO RELATED PATENTS The present application is related to U.S. Pat. No. 4,757,548 (1988) to Fenner, Jr., the disclosure of which is specifically incorporated herein by reference.",
"FIELD OF INVENTION The present invention relates generally to transducers capable of converting energy between electrical and mechanical form and, more particularly, to a transducer including a housing having flexible, dome-shaped housing portions capable of elastic deformation.",
"BACKGROUND OF THE INVENTION Transducers capable of converting energy between mechanical and electrical form have many varied uses.",
"Transducers operative to convert electrical energy into mechanical energy include conventional speakers as well as transducers capable of generating high energy vibrations.",
"A brief summary of prior art is listed below.",
"U.S. Pat. No. 4,757,548 (1988) to Fenner, Jr. discloses a speaker system with a dome-shaped enclosure cooperating with the magnet and voice coil to enhance sound waves in an adjacent solid or liquid.",
"U.S. Pat. No. 3,524,027 (1970) to Thurston et al.",
"discloses a sound enhancement speaker system having a wall mounted speaker.",
"The speaker has a flat base.",
"The magnets are a toroid and a pair of plates.",
"The voice coil is attached to a flat plate which in turn is attached to a screw mounted in the wall.",
"U.S. Pat. No. 4,399,334 (1983) to Kakiuchi discloses a headphone speaker having a dome shaped diaphragm to amplify the energy of the voice coil.",
"U.S. Pat. No. 3,567,870 (1971) to Rivera discloses a wall surface sound transducer having a pair of cup-shaped housing members.",
"The active portions of the vibrating surfaces are flat.",
"A flat plate vibrating surface, however, typically exhibits a narrow frequency band response (500-5000 Hz), and exhibits harmonic distortion due to low damping ratios.",
"U.S. Pat. No. 4,635,287 (1987) to Hirano discloses a vibrating voice coil plate activated by a magnet mounted on a flat plate or a vibrator.",
"U.S. Pat. No. 4,179,009 (1979) to Birkner discloses a landspeaker mounting assembly for a resonance panel.",
"U.S. Pat. No. 4,550,428 (1985) to Yanagishima et al.",
"discloses a car speaker in which part of the chassis of a car is used to form a permanent magnetic field.",
"U.S. Pat. No. 3,987,258 (1976) to Tsutsui et al.",
"discloses a floatable, water proof sound cabinet.",
"U.S. Pat. No. 4,187,568 (1980) to McMullan et al.",
"discloses an electromagnetic vibrator mounted in a waterbed.",
"U.S. Pat. No. Re 23,724 (1953) to Seabert discloses an underwater speaker encased in a heavy casing.",
"The diaphragm of the underwater speaker is immersible in water.",
"U.S. Pat. No. 4,514,599 (1985) to Yanagishima discloses a car speaker mountable upon a car panel in which the car panel is used as a vibrating panel during operation of the car speaker.",
"U.S. Pat. No. 4,055,170 (1977) to Nohuwra discloses a chair having a vibrating sheet positioned to be in contact with an occupant seated in the chair.",
"A speaker generates mechanical energy which drives the vibrating seat.",
"U.S. Pat. No. 4,105,024 (1978) to Raffel discloses a pair of vibrator motors mounted inside a furniture frame.",
"U.S. Pat. No. 2,778,882 (1957) to Pontzen et al.",
"discloses a microphone with a planar diaphragm having both sides exposed to the air which permits enhanced Short range sensitivity.",
"U.S. Pat. No. 3,384,719 (1968) to Lanzara discloses a set of speakers mounted in a cushioned headrest.",
"U.S. Pat. No. 2,115,098 (1938) to Engholm discloses a perforated speaker cover which forms a portion of a diaphragm assembly.",
"Deutsches Pat. No. 2,745,002 (1978) to Nohmura et al discloses a flat plate vibration generator.",
"Deutsches Pat. No. 2,115,190 (1972) discloses a waterbed having a pump or a speaker which causes generation of pulsed vibrations.",
"U.S. Pat. No. 3,524,027 to Thurston et al.",
"teaches a flat, plate-type speaker housing.",
"A toroidal magnet and a flat magnet are mounted on the back panel of the speaker housing.",
"The magnets drive a voice coil which is affixed to a flat diaphragm.",
"A spring acts as a damping device for the diaphragm.",
"As the voice coil forces the diaphragm to vibrate, an equal and opposite force causes the magnets and the back panel of the speaker housing to vibrate.",
"All the resultant vibration is transmitted into a bolt fastened in a wall, and the wall resonates with the induced vibrations.",
"This flat plate type of transducer, however, exhibits only a limited frequency response (500-5000 Hz) and also exhibits harmonic distortion.",
"Harmonic distortions result in the generation of heat energy caused as a result of oscillations of the voice coil in the magnetic field.",
"This heat energy causes heating of the transducer and reduces the life of the transducer.",
"U.S. Pat. No. 3,567,870 to Rivera teaches a modification to Thurston et al.",
"wherein the speaker housing is modified to include a pair of cup-shaped members.",
"A damping spring required in Thurston is eliminated, and a flatter (more uniform) and wider frequency response is achieved and a reduction of some harmonic distortion is achieved.",
"However, the front and back vibrating speaker housing members are flat.",
"These flat members cause harmonic distortion.",
"'548 to Fenner, Jr. achieves a higher frequency response (10-30,000 Hz) by using a dome shaped front speaker housing member.",
"Yet, the back speaker housing member remains flat, thereby causing harmonic distortion.",
"Additional harmonic distortion is created by a flat horizontal support member mounted inside the shell shaped speaker housing.",
"The present invention eliminates all flat speaker housing members.",
"A pair of symmetrical opposing domes comprise the speaker housing.",
"No support member is utilized.",
"Rather, the magnet(s) are mounted directly on the inside of the back dome member.",
"The dome members are rigid, thereby providing a high damping rate without the use of springs.",
"Other design advantages include flatter frequency responses, crush-resistant deep water high pressure housing, crush-resistant load bearing shock absorbing housing useful as shock absorbers, and vibration sensitivity foe active vibration (phase cancellation) applications.",
"SUMMARY OF THE INVENTION The present invention advantageously provides a dual domed vibration transducer which exhibits low levels of harmonic distortion and which exhibits a broad band, flat frequency response.",
"The present invention further advantageously provides a dual dome transducer housing which exhibits a high damping ratio.",
"The present invention yet further advantageously provides a dual dome transducer housing which forms a water tight enclosure.",
"The present invention still further advantageously provides a crush-resistant dual dome transducer housing.",
"Another object of the present invention is to provide the dual dome housing with adequate torsion stability to withstand use in shock absorber applications.",
"Yet another object of the present invention is to minimize the size requirements of the dual dome housing as compared to a dome/flat housing design.",
"Other features of the present invention will become apparent upon reading the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of an embodiment of the transducer of the present invention.",
"FIG. 2 is a top, partial cutaway view of the transducer of FIG. 1. FIG. 3 is a schematic block diagram of a conventional microphone sensing and speaker nullifying active noise reduction system.",
"FIG. 4 is a schematic block diagram of an active vibration phase cancellation system of an embodiment of the present invention which includes the transducer shown in FIGS. 1-2 as a portion thereof.",
"FIG. 5 is a schematic block diagram of an ultrasonic cleaning, vat agitation, and/or non-intrusive level sensing system which includes the transducer shown in FIGS. 1-2 as a portion thereof.",
"FIG. 6 is a schematic block diagram of a ship-board barnacle prevention, noise cancellation, sound output, and/or hull vibrator system which includes the transducer shown in FIGS. 1-2 as a portion thereof.",
"FIG. 7 is a sectional view of a hull showing the placement of a plurality of transducers of the system in FIG. 6. Before explaining the disclosed embodiment of the present invention in detail, it should be noted that it is to be understood that the invention is not limited in its application to the details of the particular arrangements shown in the figures and described in the specification, since the invention is capable of other embodiments.",
"Also, the terminology used herein is for the purpose of description and not of limitation.",
"DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1 a dual dome transducer 100 of an embodiment of the present invention is shown.",
"The transducer is constructed to permit immersion of the transducer 100 in a liquid.",
"The transducer 100 may be mounted to an external structure such as a bulkhead 170, by any of many various types of fasteners including, for example, a T-weld 18, an anchor bolt 13, or a nut and bolt assembly 17.",
"The transducer 100 includes a permanent magnet assembly 1.",
"The magnet assembly 1 is preferably formed of rare earth materials.",
"A magnetic ceramic material may alternately be used.",
"In the embodiment shown in FIG. 1, the assembly 1 includes a ferrous top washer 2, a ferrous bottom washer 3, and a center pole piece 4.",
"The center pole piece 4 is attached to the ferrous bottom washer 3 by a compression fit with a ring type magnet 5.",
"The magnet assembly 1 is held together by an appropriate adhesive.",
"The magnet assembly 1 is centered in a bottom dome half 11 forming a portion of the housing of the transducer 100 and is secured in position with a viscous glue 6.",
"An interference fit is formed between the sloped surface 30 of the bottom washer 3 and the viscous glue 6.",
"A raised boss area 7 in the bottom dome 11 supports a female fastening device 8.",
"The device 8 provides for mounting of the transducer to an external structure such as a motor mount.",
"See FIG. 4. The female fastener 8 is held in place by both compression fit and an appropriate adhesive.",
"The active side of the dual dome transducer 100 is formed a top dome half 10.",
"A raised boss 9 contains a second female fastener 12 used for fastening to bulkhead 170 as shown.",
"A core 21 is used as a support means for voice coil 22.",
"The core 21 is held in place on raised boss 9 by an appropriate adhesive.",
"The portion of the core 21 about which the voice coil 22 is supported extends into a slot 103 defined by a gap separating the center pole piece 4 from the washer 2 and ring type magnet 5 of the magnet assembly 1.",
"The core 21 extends into the magnet assembly 1, and the coil 22 is suspended at a mid point 200 of the ferrous washer 2 in close proximity to center pole piece 4.",
"The top dome half 10 of the housing of the transducer 100 is secured about its circumference 26 to the bottom dome half 11 by an appropriate adhesive.",
"The housing of the transducer 100 forms a sealed structure when a water tight strain relief element 23 is used.",
"A two conductor wire 24 is then connected to the coil wire leads 25 which then pass through water tight strain relief element 23.",
"Anchor bolt 13 is utilized for attaching the dual dome transducer 100 to wooden objects.",
"The anchor bolt 13 includes threads 14 to permit threaded engagement with the wooden object.",
"The anchor bolt 13 also includes threads 15 to permit threaded engagement with the fastener 12 supported at the top dome half 10 of the housing of the transducer 100.",
"A lock nut 16 is further utilized, to be tightened down onto female fastener 17 to securely tighten the fitting between the bolt 13 and the transducer 100.",
"Nut and bolt assembly 17 may be used for attachment of the transducer 100 to articles.",
"For instance if the transducer is to be bolted to the bulkhead 170, when bolting through the bulkhead 170 is possible, the nut and bolt assembly 17 may be used.",
"As a means for mounting the transducer 100 to metal or fiberglass bulkheads 180, a male fastener 20 may be glued or welded, shown by weld connection 19, to bulkhead 180, thereby forming T-weld 18.",
"Male fasteners 13, 17, and 18 may be used in conjunction with female fasteners 8 and 12 for mounting of the transducer 100 to any article.",
"Optionally a ferro-fluid F positioned in the slot 103 defined by the elements of the magnet assembly 1, such as Ferro-Fluidics L 11®, is held in place by magnetic poles N,S of the magnet assembly 1.",
"This ferro-fluid F increases the power handling capability of the voice coil 22 by up to three times.",
"In summary the dual dome transducer 100 comprises a top dome half 10, a bottom dome half 11, an inside space 101 defined therebetween, and a speaker assembly 102 having a core 21 affixed to the upper dome half within the inside space 101.",
"In operation the dome halves expand and contract away and towards one another in response to the energy generated during operation of the speaker assembly 102, or in response to induced vibrations.",
"Referring next to FIG. 2, the transducer 100 is again shown.",
"The distance d1 spanning opposing sides of the transducer is approximately 8 inches.",
"The performance of the transducer 100 duplicates the performance of the prior art '548 Fenner, Jr. device but is of a diameter six inches smaller than the diameter of '548 Fenner Jr. device which is 14 inches in diameter.",
"Dome halves 10, 11 are preferably made of 1/8 inch Lucite Lt®, or a carbon and graphite composite.",
"Core 21 is preferably made of Kapton©.",
"The ring type magnet 5 is preferably made of Neodymium iron boron having a magnetic gauss oerstad (MGO) of up to 54 MGO.",
"Referring next to FIG. 3 is a phase cancellation system P100, known in the art.",
"A microphone P1 picks up sound S1 which needs to be canceled.",
"A frequency spectrum analyzer P2 is coupled to receive a signal generated by the microphone P1 and is utilized to sort dominant frequencies of the signal applied thereto.",
"The resulting signal is sent to a frequency matching filter P3.",
"The filter P3 matches the inherent frequency response of the microphone P1 to the inherent frequency response of the loud speaker P7.",
"The resulting signal is passed on to pre-amplifier P4 which increases the signal strength of the signal applied thereto.",
"The signal is then inverted by the signal invertor P5 which provides a signal that is 180° out of phase with the input sound S1.",
"The resulting processed signal is then amplified by amplifier P6, and the amplified processed signal is sent to loud speaker P7.",
"The sound S2 generated by the speaker P7 is 180° out of phase with the input sound S1.",
"The overall effect is a reduction of the sound pressure level of resultant sounds S1, S2.",
"FIG. 4 illustrates a system 400 incorporating the acoustic transducer 100 to provide vibration phase cancellation using a single transducer 100 as a co-spatial instrument capable of sensing and transmitting vibrations.",
"Thus, the transducer 100 is attached in accordance with previous instruction to the vibrating motor 28 and chassis member 34 where it is desired to reduce the vibration.",
"The sequence begins with an electric current being generated in the voice coil 22 by movement produced by the vibrating motor 28.",
"An electrical input signal representative of electric current generated in the voice coil 22 is applied to a buffer 29 on lines 24 and is stored in buffer 29 for a period of approximately 50 micro seconds or less.",
"The signal is then passed on to a phase invertor 30 and then to preamplifier 33.",
"The phase inverted, preamplified signal is then passed to adjustable gain amplifier 32 where the signal is amplified to match the amplitude of the input signal.",
"The amplified inverted signal is then sent back to acoustic transducer 100 where the electrical energy is converted to physical movement that is 180° out of phase with the vibrations generated by the vibrating motor 28.",
"This provides vibration cancellation.",
"The switching sequencer 31 is utilized to switch the electrical input signal off to buffer 29 when the amplified signal is sent to transducer 100.",
"Conversely the switching sequencer 31 will switch off the amplified signal while the input signal is being received by the buffer 29.",
"The time span for this sequence has been prescribed to be 50 micro seconds or less in that this is the longest duration of sound that is not detectable by the human sense.",
"The acoustic transducer 100 as described by this invention displays inherent mechanical properties that are necessary for this system 400 to function.",
"Those inherent properties include high damping characteristics that preclude the transducer from resonating or continuing to move after the electronic signal is switched off.",
"By using the single transducer as the sending and receiving device the input frequency and amplitude is directly proportional to the output frequency and amplitude.",
"This matching eliminates the need for complex filtering or equalization between components.",
"Referring next to FIG. 5 a multi-purpose vat system 500 is shown.",
"Liquid in a tank 51 is energized by vibrations of the transducer 100 mounted upon a sidewall of the tank 51.",
"When the energizing frequency of the vibrations of the transducer 100 (as supplied by a frequency generator 53 and amplified by amplifier 54) is in the ultrasonic range the tank 51 may be used as a container to ultrasonically clean objects 501 inserted into the tank 51.",
"A solvent 502 holds the dirt particles removed during the ultrasonic cleaning process.",
"A level sensing application is created by varying the frequency of the vibrations generated by the transducer 100 supplied to the tank 51 to determine the natural harmonic resonance of the liquid in the tank.",
"Thereafter, any shift in the resulting output frequency may be interpreted as a change in level of the liquid in the tank.",
"The frequency shift comparator 55 supplies a signal to the linearized output device 56 based on the differential between the determined natural harmonic frequency and the existing frequency which will shift as the level of the liquid in the tank rises or falls.",
"The switching sequencer 57 changes the operating mode from sensing via frequency shift comparator 55 to sending via frequency generator 57.",
"The linearized level signal may then be displayed on a gauge 58.",
"Another application for the system 500 is to use a high frequency signal as produced by the frequency generator 53 and amplified by amplifier 54.",
"This signal may be used to keep the inside of tank 51 clean.",
"System components 53-57 may all be incorporated in a solid state chip mounted inside transducer 100.",
"Referring next to FIGS. 6, 7 a multi-purpose ship-board system 600 is shown.",
"In this system a single high gain acoustic transducer 100 is utilized to provide a multitude of uses.",
"The transducers 100 are rigidly attached to the interior of the hull 71.",
"The desired hull effect is initiated by the function selector 64.",
"The low frequency generator 65 is utilized to provide a low frequency signal to the amplifier 69.",
"This amplified signal is converted to a physical vibration by the transducer 100.",
"When this low frequency is transmitted through the hull 71, the low frequency physical vibration prevents barnacle formation as is known in the art.",
"A second application is the vibration phase cancellation network 66, as described previously with respect to FIG. 4. The teaching of FIG. 4 is used to cancel vibrations in the hull 71 that are commonly generated in engineering spaces such as the engine room.",
"A third application is the recorded media output 67.",
"It is utilized to transmit sound through hull 71 such as the sound image of a school of fish.",
"A fourth application is the ultrasonic frequency generator 68.",
"It is utilized to create an ultrasonic vibration in the hull 71 which causes a cavitation layer between the hull 71 and the water 711.",
"This cavitation layer reduces the friction coefficient of the hull 71 reducing fuel consumption and increasing speed throughway the water 711.",
"A fifth application shows the microphone 610 utilized to broadcast verbal messages throughway the hull 71 such as for diver recall.",
"In all systems the signal is sent to the amplifier 79 and then to the transducers 100.",
"All of the above applications may be used concurrently.",
"It is known in the art that a configuration of four square magnets could be used to replace the ring type magnet 5.",
"Additionally a cup shaped ferrous metal assembly having a button shaped Neodymium iron boron magnet with a top ferrous metal washer could be used."
] |
FIELD OF THE INVENTION
[0001] The present invention relates to a geared motor which is provided with a stopper mechanism in its gear train and a pointer type display device.
BACKGROUND ART
[0002] In a pointer type display device and the like, a geared motor including a motor and a gear train disposed inside a case is used and a pointer is fixed to an output member of the geared motor (Patent Literature 1). In Patent Literature 1, the geared motor is proposed so that a stopper mechanism is provided which is structured to stop a gear at a home position where a pointer indicates the zero point. More specifically, a structure has been proposed that, in a first gear integrally turned with an output member and a second gear meshed with the first gear for driving the first gear, a gear side protruded part is provided at a substantially middle position in a radial direction of the first gear and a support member side protruded part is provided in a support member on an imaginary line passing through a turning center of the first gear and a rotation center of the second gear and, when the first gear is turned to the position where the pointer indicates the zero point, the gear side protruded part and the support member side protruded part are abutted with each other.
CITATION LIST
Patent Literature
[0003] [PTL 1] Japanese Patent Laid-Open No. 2001-327149
SUMMARY OF THE INVENTION
Technical Problem
[0004] However, when the pointer is returned to the home position and the gear side protruded part provided in the first gear is abutted with the support member side protruded part, the first gear is rebounded in a reverse direction to cause the pointer to be shaken. In other words, in a case that the pointer is to be returned to the home position, a gear connected with the second gear, a rotor of a motor part and the like are also turned and thus, when the stopper mechanism is operated and the first gear is stopped, the second gear is also going to be stopped. However, the second gear receives an inertia torque from the rotor and the like in an opposite direction and the inertia torque is transmitted to the first gear and, as a result, the first gear is rebounded.
[0005] Therefore, in view of the problem described above, an objective of the present invention is to provide a geared motor and a pointer type display device in which rebounding of a gear is restrained even when a stopper mechanism provided in a gear train is operated.
Solution to Problem
[0006] To achieve the above mentioned objective, the present invention provides a geared motor including a motor part, an output member, a gear train including a plurality of gears structured to transmit rotation of the motor part to the output member, a support member which supports the motor part, the output member and the gear train, and a stopper mechanism which includes a stopper abutting part provided in a first gear of the plurality of the gears and a stopper abutted part provided in the support member and is structured so that, when the first gear is turned to one side in a circumferential direction, the stopper abutting part is abutted with the stopper abutted part to restrict a movable range of turning of the first gear to the one side. The stopper abutted part is an other side end part located on the other side in the circumferential direction of a support body side protruded part which is protruded from an outer side in a radial direction toward an inner side in the radial direction and toward a turning center of the first gear, and a width dimension in the circumferential direction on an inner side in the radial direction of the support body side protruded part is set to be narrower than that on its outer side in the radial direction.
[0007] In the present invention, a width dimension in the circumferential direction on an inner side in the radial direction of the support body side protruded part is set to be narrower than that on its outer side in the radial direction. Therefore, even in a case that the width in the circumferential direction of the support body side protruded part is set to be wide to some extent for securing strength, when the stopper mechanism is operated, the stopper abutting part and the stopper abutted part are abutted with each other at a position near the turning center axil line of the first gear. Accordingly, when the stopper mechanism is operated, collision energy applied to the first gear is small and thus rebounding of the first gear can be restrained. Further, a movable range to the one side of the first gear can be made wide.
[0008] In the present invention, it is preferable that the first gear is provided with a plate-shaped part in which teeth are formed on its outer peripheral face and a body part which is protruded from the plate-shaped part in a turning center axial line direction of the first gear at a center of the first gear, and the stopper abutting part is an one side end part located on the one side of a gear side protruded part which is integrally formed with the body part on an outer peripheral face of the body part. According to this structure, the stopper abutting part (one side end part of the gear side protruded part) is abutted with the stopper abutted part at a position near the turning center axial line of the first gear. Therefore, when the stopper mechanism is operated, collision energy applied to the first gear is small and thus rebounding of the first gear can be restrained.
[0009] In the present invention, it is preferable that the gear side protruded part is integrally formed with the plate-shaped part. According to this structure, the strength of the gear side protruded part can be increased.
[0010] In the present invention, it is preferable that the plate-shaped part is formed with plate-shaped springs which are elastically abutted with the support member in the turning center axial line direction of the first gear at a plurality of positions in the circumferential direction, and the gear side protruded part is formed at an angular position corresponding to a portion between the plate-shaped springs adjacent to each other in the circumferential direction. According to this structure, even when the plate-shaped spring is formed in the plate-shaped part of the first gear, restriction of the position for forming the gear side protruded part is small. Therefore, the gear side protruded part is easily provided on an inner side in the radial direction.
[0011] In the present invention, it is preferable that the support member includes a cylindrical tube part with which the plate-shaped spring is abutted, and the stopper abutted part is integrally formed with the cylindrical tube part on an inner side in a radial direction of the cylindrical tube part. According to this structure, the strength of the stopper abutted part can be increased.
[0012] In the present invention, it is preferable that the plurality of the gears includes a second gear which is meshed with the first gear to drive the first gear, and the stopper abutted part is provided at a position where the first gear is applied with a reaction force in a direction separated from the second gear when the first gear is turned to the one side and the stopper abutting part is abutted with the stopper abutted part. According to this structure, when the stopper abutting part of the first gear is turned to one side in the circumferential direction and is abutted with the stopper abutted part of the support member, the first gear receives a reaction force in a direction separated from the second gear. Therefore, engagement of the first gear with the second gear becomes shallow and thus an inertia torque in an opposite direction from the second gear is hard to be transmitted to the first gear. Accordingly, rebounding of the first gear can be restrained.
[0013] In the present invention, it is preferable that a turning angular range of the first gear is divided into a first angular range and a second angular range by an imaginary line passing through a turning center of the first gear and a rotation center of the second gear and, in the first angular range where the stopper abutting part is moved in a direction coming close to the rotation center of the second gear when the first gear is turned to the one side, the stopper mechanism is structured so that the stopper abutting part is abutted with the stopper abutted part in an angular range of 90±60° with respect to the imaginary line when viewed from the rotation center of the first gear. According to this structure, when the stopper abutting part is turned to one side in the circumferential direction and is abutted with the stopper abutted part of the support member, the first gear is easy to receive a reaction force in a direction separated from the second gear. Therefore, engagement of the first gear with the second gear becomes shallow and thus an inertia torque in an opposite direction from the second gear is hard to be transmitted to the first gear. Accordingly, rebounding of the first gear can be restrained.
[0014] In the present invention, it is preferable that the stopper mechanism is structured so that the stopper abutting part is abutted with the stopper abutted part in an angular range of 90±10° with respect to the imaginary line when viewed from the rotation center of the first gear. According to this structure, when the stopper abutting part is turned to the one side in the circumferential direction and is abutted with the stopper abutted part of the support member, the first gear is further easily received with a reaction force in a direction separated from the second gear. Therefore, engagement of the first gear with the second gear becomes further shallow and thus an inertia torque in an opposite direction from the second gear is hard to be transmitted to the first gear. Accordingly, rebounding of the first gear can be restrained.
[0015] In the present invention, it is preferable that the first gear and the output member are integrally turned with each other. According to this structure, a movable range of the output member can be directly restricted by the stopper mechanism.
[0016] The geared motor in accordance with the present invention may be used, for example, in a pointer type display device and, in this case, the pointer type display device has a pointer which is held by the output member. In this case, it may be structured that a stopping position by the stopper mechanism corresponds to a home position of the pointer.
Effects of the Invention
[0017] In the present invention, a width dimension in the circumferential direction on an inner side in the radial direction of the support body side protruded part is set to be narrower than that on its outer side in the radial direction. Therefore, even in a case that the width in the circumferential direction of the support body side protruded part is set to be wide to some extent for securing strength, when the stopper mechanism is operated, the stopper abutting part and the stopper abutted part are abutted with each other at a position near the turning center axil line of the first gear. Accordingly, when the stopper mechanism is operated, collision energy applied to the first gear is small and thus rebounding of the first gear can be restrained. Further, a movable range to the one side of the first gear can be made wide.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIGS. 1 a and 1 b are explanatory views showing a geared motor to which the present invention is applied.
[0019] FIG. 2 is a cross-sectional view showing a geared motor to which the present invention is applied and which is cut at a position passing a gear train.
[0020] FIGS. 3 a and 3 b are exploded perspective views showing a geared motor to which the present invention is applied and which is viewed from an output side.
[0021] FIGS. 4 a and 4 b are exploded perspective views showing a geared motor to which the present invention is applied and which is viewed from an opposite-to-output side.
[0022] FIGS. 5 a , 5 b and 5 c are explanatory views showing a driven gear which is used in a geared motor to which the present invention is applied.
[0023] FIG. 6 is an explanatory view showing a planar structure of a stopper mechanism which is structured in a geared motor to which the present invention is applied.
DESCRIPTION OF EMBODIMENTS
[0024] A geared motor and a pointer type display device to which the present invention is applied will be described below with reference to the accompanying drawings. In the following descriptions, in a direction where a turning center axial line “L” of an output member 10 is extended, one side to which the output member 10 is protruded is referred to as an output side “L 1 ” and an opposite side (the other side) to the side where the output member 10 is protruded is referred to as an opposite-to-output side “L 2 ”. Further, an axial line of a rotor 5 in a motor part 1 is a rotation center axial line “L 0 ” and an axial line of a drive side gear 41 of a gear train 4 is a rotation center axial line “L 5 ”. Further, for convenience, the one side of each of the rotation center axial lines “L 0 ” and “L 5 ” is referred to as the output side “L 1 ”, and the other side of each of the rotation center axial lines “L 0 ” and “L 5 ” is referred to as the opposite-to-output side “L 2 ”.
(Entire Structure of Pointer Type Display Device)
[0025] FIGS. 1 a and 1 b are explanatory views showing a geared motor 100 to which the present invention is applied. FIG. 1 a is a perspective view showing a geared motor 100 which is viewed from an output side “L 1 ” and FIG. 1 b is a perspective view showing the geared motor 100 which is viewed from an opposite-to-output side “L 2 ”. FIG. 2 is a cross-sectional view showing the geared motor 100 to which the present invention is applied and which is cut at a position passing a gear train 4 . FIGS. 3 a and 3 b are exploded perspective views showing the geared motor 100 to which the present invention is applied and which is viewed from an output side “L 1 ”. FIG. 3 a is an exploded perspective view showing a state that a second case member 22 is separated from a first case member 21 , and FIG. 3 b is an exploded perspective view showing a state that a gear train 4 and the like are detached from the first case member 21 . FIGS. 4 a and 4 b are exploded perspective views showing the geared motor 100 to which the present invention is applied and which is viewed from an opposite-to-output side “L 2 ”. FIG. 4 a is an exploded perspective view showing a state that the first case member 21 is separated from the second case member 22 , and FIG. 4 b is an exploded perspective view showing a state that the gear train 4 and the like are detached from the second case member 22 .
[0026] The geared motor 100 shown in FIGS. 1 a through 4 b is structured so that a shaft-shaped output member 10 is protruded from a case 2 to the output side “L 1 ” in the turning center axial line “L” direction. The geared motor 100 in this embodiment is used in a pointer type display device 200 and, as shown in FIG. 1 a , a pointer 11 is connected with the output member 10 .
[0027] The case 2 includes a first case member 21 formed in a substantially circular shape when viewed in the turning center axial line “L” direction and a second case member 22 formed in a substantially circular shape when viewed in the turning center axial line “L” direction. The second case member 22 is overlapped with the first case member 21 from the output side “L 1 ”. The case 2 is a support member which supports a motor part 1 , the gear train 4 and the output member 10 described below.
[0028] The first case member 21 is provided with an end plate part 210 and a side plate part 211 in a tube shape which is protruded to the output side “L 1 ” from an outer side edge of the end plate part 210 . An outer peripheral face of the side plate part 211 is formed with a hook 219 at a plurality of positions in a circumferential direction. The second case member 22 is provided with an end plate part 220 and a side plate part 221 in a tube shape which is protruded to the opposite-to-output side “L 2 ” from an outer side edge of the end plate part 220 . An engaging protruded part 229 is formed in the side plate part 221 at a plurality of positions in the circumferential direction. Therefore, when the hooks 219 and the engaging protruded parts 229 are engaged with each other and the first case member 21 and the second case member 22 are combined with each other, the case 2 is structured. In the first case member 21 , a protruded part 212 which is, for example, used for fixing the geared motor 100 is protruded toward the opposite-to-output side “L 2 ” from the end plate part 210 . Further, in the second case member 22 , protruded parts 222 which are, for example, used for fixing the geared motor 100 are protruded toward the output side “L 1 ” from the end plate part 220 .
(Structure of Motor Part 1 )
[0029] The geared motor 100 includes a motor part 1 in an inside of the case 2 . The motor part 1 is a drive source for the output member 10 . The motor part 1 is a stepping motor which includes a rotor 5 and a stator 6 disposed around the rotor 5 . The rotor 5 is rotatably supported by a support shaft 51 . An end part on the opposite-to-output side “L 2 ” of the support shaft 51 is held by a shaft hole 213 a formed in the end plate part 210 of the first case member 21 , and an end part on the output side “L 1 ” of the support shaft 51 is held by a shaft hole 223 a formed in the end plate part 220 of the second case member 22 .
[0030] The rotor 5 includes a pinion 58 provided at an end part on the opposite-to-output side “L 2 ” in a rotation center axial line “L 0 ” direction and a magnet 50 formed in a cylindrical tube shape. An “S”-pole and an “N”-pole are alternately formed at equal angular intervals on an outer peripheral face of the magnet 50 . In this embodiment, the magnet 50 and the pinion 58 made of resin are integrated each other by insert molding. The stator 6 includes a stator core 60 provided with a plurality of salient poles which face the outer peripheral face of the magnet 50 with a gap space therebetween. A coil 8 is wound around each of two salient poles (main pole) of the plurality of the salient poles through a coil bobbin 7 . The stator core 60 is formed in a plate shape and is structured by laminating a plurality of magnetic plates which are punched in a predetermined shape. The stator core 60 is formed with a hole 68 through which a support shaft 410 of a drive side gear 41 described below is penetrated. The coil bobbin 7 holds a plurality of terminal pins 70 to which end parts of the coil 8 are bound and connected. An end part of the terminal pin 70 is protruded to the output side “L 1 ” through a hole 223 d which is formed in the end plate part 220 of the second case member 22 .
[0031] The geared motor 100 includes a gear train 4 structured to decelerate rotation of the rotor 5 and transmit it to the output member 10 . In this embodiment, the gear train 4 includes the pinion 58 , a drive side gear 41 (second gear in the present invention) meshing with the pinion 58 , and a driven gear 42 (first gear in the present invention) meshing with the drive side gear 41 . The drive side gear 41 is provided with a large diameter gear 411 meshing with the pinion 58 of the rotor 5 and a small diameter gear 412 coaxially formed with the large diameter gear 411 . The drive side gear 41 is rotatably supported by the support shaft 410 . An end part on the opposite-to-output side “L 2 ” of the support shaft 410 is held by a shaft hole 213 b formed in the end plate part 210 of the first case member 21 . An end part on the output side “L 1 ” of the support shaft 410 is held by a shaft hole 223 b formed in a column part 226 which is formed in the end plate part 220 of the second case member 22 . The driven gear 42 is provided with a plate-shaped part 43 in a circular plate shape whose outer peripheral face is formed with outer teeth 431 meshing with the small diameter gear 412 .
(Structure of Driven Gear 42 )
[0032] FIGS. 5 a , 5 b and 5 c are explanatory views showing the driven gear 42 which is used in the geared motor 100 to which the present invention is applied. FIG. 5 a is a perspective view showing the driven gear 42 which is viewed in an oblique direction on the output side “L 1 ”, FIG. 5 b is a plan view showing the driven gear 42 which is viewed in an oblique direction on the opposite-to-output side “L 2 ”, and FIG. 5 c is a side view showing the driven gear 42 .
[0033] The driven gear 42 is a final gear structured to transmit its rotation to the output member 10 and to be integrally turned with the output member 10 . The driven gear 42 is structured as described below.
[0034] In FIGS. 5 a , 5 b and 5 c , the driven gear 42 is provided with a shaft-shaped body part 44 , which is protruded from the center of the plate-shaped part 43 to the output side “L 1 ”, and a circular protruded part 45 which is protruded from the center of the plate-shaped part 43 to the opposite-to-output side “L 2 ”. A shaft hole 440 , i.e., a through hole into which the output member 10 is fitted is provided in the body part 44 and the circular protruded part 45 . The driven gear 42 and the output member 10 are integrally turned with each other.
[0035] The plate-shaped part 43 is formed with a groove 47 which penetrates the plate-shaped part 43 in the turning center axial line “L” direction. The groove 47 is extended to one side around the turning center axial line “L” and then bent in a “U”-shape and extended to the other side in the circumferential direction. As a result, a portion of the plate-shaped part 43 which is surrounded by the groove 47 is formed to be a plate-shaped spring 46 whose one end in the circumferential direction is connected with the plate-shaped part 43 . A protruded part 461 protruded toward the output side “L 1 ” is formed on a tip end side of the plate-shaped spring 46 . In this embodiment, the plate-shaped spring 46 is formed at two positions with equal angular intervals in the circumferential direction so as to extend in the same direction. An angular interval of two plate-shaped springs 46 is 180°.
[0036] The plate-shaped part 43 is formed with a gear side protruded part 48 protruded to the output side “L 1 ” and to an outer side in a radial direction at an angular position between two plate-shaped springs 46 in the circumferential direction. The gear side protruded part 48 structures a stopper mechanism 9 which restricts a movable range when the driven gear 42 is turned in a counterclockwise direction “CCW” (one side in the circumferential direction) by abutting with a support body side protruded part 28 described below.
(Support Structure for Driven Gear 42 and Output Member 10 )
[0037] As shown in FIGS. 3 a through 4 b , the end plate part 210 of the first case member 21 is formed with a cylindrical tube part 215 protruded to the output side “L 1 ” and a cylindrical tube part 216 protruded to the opposite-to-output side “L 2 ”. The cylindrical tube parts 215 and 216 are formed with shaft holes 215 a and 216 a which turnably support an opposite-to-output side end part of the output member 10 .
[0038] On the other hand, the end plate part 220 of the second case member 22 is formed with a cylindrical tube part 225 which is protruded to the output side “L 1 ”. The cylindrical tube part 225 is formed with a shaft hole 225 a which turnably supports an output side portion of the output member 10 .
[0039] A face on the opposite-to-output side “L 2 ” of the end plate part 220 of the second case member 22 is formed with a cylindrical tube part 227 into which the body part 44 of the driven gear 42 is entered and plate-shaped ribs 224 which are extended from the cylindrical tube part 227 toward outer sides in a radial direction. An inner diameter of the cylindrical tube part 227 is larger than an outer diameter of the body part 44 of the driven gear 42 , and an inner face of the cylindrical tube part 227 does not contact with the body part 44 of the driven gear 42 . The ribs 224 are formed at four positions with equal angular intervals around the cylindrical tube part 227 . Three ribs 224 a , 224 b and 224 c of four ribs 224 are connected with the side plate part 221 and the remaining one rib 224 d is connected with the column part 226 formed with the shaft hole 223 b.
[0040] In this embodiment, the circular protruded part 45 of the driven gear 42 is abutted with the cylindrical tube part 215 of the first case member 21 and movement of the driven gear 42 to the opposite-to-output side “L 2 ” is prevented. Further, the protruded parts 461 of the plate-shaped springs 46 of the driven gear 42 are elastically abutted with an end face on the opposite-to-output side “L 2 ” of the cylindrical tube part 227 of the second case member 22 and movement of the driven gear 42 to the output side “L 1 ” is restricted. Therefore, the driven gear 42 and the output member 10 are restrained from rattling in the turning center axial line “L” direction.
(Operations)
[0041] In the geared motor 100 and the pointer type display device 200 structured as described above, when electrical power is supplied to the coil 8 through the terminal pins 70 in a state that the pointer 11 is stopped at the zero point (home position), the rotor 5 is rotated and the rotation is transmitted to the output member 10 through the gear train 4 . Therefore, the pointer 11 connected with the output member 10 is turned in the clockwise direction CW. In this case, an angular position of the pointer 11 is changed by inputting a predetermined number of drive pulses into the coil 8 and, after the pointer 11 is turned to a target position in the clockwise direction CW, the pointer 11 is stopped. Further, when drive pulses for reverse rotation are supplied, the pointer can be turned in the counterclockwise direction CCW to another target position.
(Structure of Stopper Mechanism)
[0042] FIG. 6 is an explanatory view showing a planar structure of a stopper mechanism 9 which is structured in the geared motor 100 to which the present invention is applied. In FIG. 6 , the gear train 4 is shown by the solid line and the second case member 22 is shown by the alternate long and short dash line.
[0043] In FIG. 6 , in the geared motor 100 in this embodiment, a stopper mechanism 9 is structured between the driven gear 42 and the second case member 22 (support member) so that, when the pointer 11 shown in FIG. 1 a is turned in the counterclockwise direction CCW and reached to the home position indicating the zero point, a stopper abutting part 91 provided in the driven gear 42 is abutted with a stopper abutted part 92 provided in the second case member 22 to restrict a movable range in the counterclockwise direction CCW (to one side around the turning center axial line “L”) of the driven gear 42 .
[0044] In this embodiment, the driven gear 42 is provided with a gear side protruded part 48 protruding toward an outer side in the radial direction on an outer peripheral face of the body part 44 which is protruded to the output side “L 1 ” from the plate-shaped part 43 at the center of the driven gear 42 . The stopper abutting part 91 is structured by an end part 481 (one side end part) which is located on the counterclockwise direction “CCW” side of the gear side protruded part 48 . The gear side protruded part 48 is integrally formed with the body part 44 and is also integrally formed with the plate-shaped part 43 .
[0045] In this embodiment, the plate-shaped part 43 is formed with the plate-shaped spring 46 and the groove 47 at two positions in the circumferential direction, and the gear side protruded part 48 is formed at an angular position corresponding to a portion between the plate-shaped springs 46 adjacent to each other in the circumferential direction. Therefore, although an end part on an outer side in the radial direction of the gear side protruded part 48 is located on an outer side in the radial direction with respect to a portion on an inner side in the radial direction of the groove 47 , since the gear side protruded part 48 and the groove 47 are displaced from each other in the circumferential direction, the gear side protruded part 48 and the body part 44 can be integrally formed with each other. In this embodiment, the gear side protruded part 48 is formed in a planar shape in which a width dimension in the circumferential direction on its inner side in the radial direction is shorter than a width dimension in the circumferential direction on its outer side in the radial direction. Therefore, a rotatable angular range of the driven gear 42 is wide. However, it may be structured that a width dimension in the circumferential direction on an inner side in the radial direction of the gear side protruded part 48 and a width dimension in the circumferential direction on its outer side in the radial direction are equal to each other, or that a width dimension in the circumferential direction on its inner side in the radial direction is longer than a width dimension in the circumferential direction on its outer side in the radial direction.
[0046] The second case member 22 is provided with a support body side protruded part 28 which is protruded from the end plate part 220 to the opposite-to-output side “L 2 ”. The stopper abutted part 92 is structured by an end part 281 (the other side end part) on a side in the clockwise direction CW of the support body side protruded part 28 (the other side around the turning center axial line “L”). In this embodiment, the support body side protruded part 28 is protruded from an inner peripheral face of the cylindrical tube part 227 toward the turning center axial line “L” of the driven gear 42 on an inner side of the cylindrical tube part 227 , and an end part on an outer side in the radial direction of the support body side protruded part 28 and the inner peripheral face of the cylindrical tube part 227 are connected with each other.
[0047] In this embodiment, the support body side protruded part 28 is provided with a planar shape having a substantially trapezoid and a width dimension in the circumferential direction on its inner side in the radial direction is narrower than that on its outer side in the radial direction. In other words, the support body side protruded part 28 is protruded from the inner peripheral face of the cylindrical tube part 227 to the inner side in the radial direction along an extended line of the rib 224 a on the inner side of the cylindrical tube part 227 . In this case, a width dimension “W 1 ” on the outer side in the radial direction of the support body side protruded part 28 is substantially equal to a width dimension of the rib 224 a . However, a width dimension “W 2 ” on its inner side in the radial direction is set to be narrower than the width dimension of the rib 224 a . In other words, the width dimension “W 1 ” on the outer side in the radial direction of the support body side protruded part 28 and the width dimension “W 2 ” on its inner side in the radial direction are set in the following relationship:
[0048] the width dimension “W 1 ”>the width dimension “W 2 ”.
[0049] Further, the stopper abutted part 92 (end part 281 of the support body side protruded part 28 ) is provided at a position where the driven gear 42 receives a reaction force in a direction separated from the drive side gear 41 when the driven gear 42 is turned in the counterclockwise direction CCW and the stopper abutting part 91 (end part 481 of the gear side protruded part 48 ) is abutted with the stopper abutted part 92 . More specifically, when a turning angle range of the driven gear 42 is divided into a first angular range θ 1 and a second angular range θ 2 by an imaginary line “L 11 ” passing through a turning center of the driven gear 42 (turning center axial line “L”) and a rotation center of the drive side gear 41 (rotation center axial line “L 5 ”), the stopper abutted part 92 (end part 281 of the support body side protruded part 28 ) is disposed in the first angular range θ 1 in which the stopper abutting part 91 is moved in a direction so as to come close to the rotation center of the drive side gear 41 when the driven gear 42 is turned in the counterclockwise direction CCW.
[0050] Further, the stopper abutted part 92 is provided in an angular range of 90±60° with respect to the imaginary line “L 11 ” when viewed from the turning center of the driven gear 42 . Especially, in this embodiment, the stopper abutted part 92 is provided in an angular range of 90±10° with respect to the imaginary line “L 11 ” when viewed from the turning center of the driven gear 42 . Therefore, when the driven gear 42 is turned in the counterclockwise direction CCW and the stopper abutting part (end part 481 of the gear side protruded part 48 ) is abutted with the stopper abutted part 92 , the driven gear 42 is surely received with a reaction force in a direction separated from the drive side gear 41 .
Principal Effects in this Embodiment
[0051] As described above, in the geared motor 100 and the pointer type display device 200 in this embodiment, the stopper mechanism 9 is provided which determines a movable range of the driven gear 42 when the driven gear 42 (output member 10 ) is turned in the counterclockwise direction CCW. Therefore, the position of the pointer 11 indicating the zero point can be determined in which the position where the stopper mechanism 9 is operated is determined as a home position of the driven gear 42 .
[0052] In this embodiment, in the stopper abutting part 91 and the stopper abutted part 92 which structure the stopper mechanism 9 , the stopper abutting part 91 is an end part 481 of the gear side protruded part 48 which is integrally formed with the body part 44 on an outer peripheral face of the body part 44 of the driven gear 42 . Therefore, the stopper abutting part 91 is abutted with the stopper abutted part 92 at a position near the turning center axial line “L” of the driven gear 42 . Accordingly, when the stopper mechanism 9 is operated, collision energy received by the driven gear 42 is small and thus rebounding of the driven gear 42 can be restrained. As a result, when the driven gear 42 is turned in the counterclockwise direction CCW toward the zero point of the pointer 11 and the zero point is indicated, the pointer 11 is hard to be shaken. Further, the gear side protruded part 48 is integrally formed with the plate-shaped part 43 of the driven gear 42 and thus the strength of the gear side protruded part 48 can be increased.
[0053] The plate-shaped part 43 is formed with the plate-shaped springs 46 at a plurality of positions in the circumferential direction and the gear side protruded part 48 is formed at an angular position corresponding to a portion between the plate-shaped springs 46 adjacent to each other in the circumferential direction. Therefore, even when the plate-shaped springs 46 are formed in the plate-shaped part 43 , restriction of the position for forming the gear side protruded part 48 is reduced. Accordingly, the gear side protruded part 48 is easily provided on an inner side in the radial direction.
[0054] On the other hand, the stopper abutted part 92 is the end part 281 of the support body side protruded part 28 which is protruded toward the turning center of the driven gear 42 from an outer side in the radial direction to an inner side in the radial direction, and a width dimension in the circumferential direction of the support body side protruded part 28 on the inner side in the radial direction is narrower than that on its outer side in the radial direction. Therefore, even in a case that the width in the circumferential direction of the support body side protruded part 28 is set to be wide to some extent for securing strength, when the stopper mechanism 9 is operated, the stopper abutting part 91 and the stopper abutted part 92 are abutted with each other at a position which is near to the turning center of the driven gear 42 . Therefore, when the stopper mechanism 9 is operated, collision energy applied to the driven gear 42 is small and thus rebounding of the driven gear 42 can be restrained. Accordingly, when the pointer 11 is turned in the counterclockwise direction CCW toward the zero point of the pointer 11 and the zero point is indicated, the pointer 11 is hard to be shaken.
[0055] The width dimension in the circumferential direction of the support body side protruded part 28 is narrower on an inner side in the radial direction than that on its outer side in the radial direction and thus a movable range in the counterclockwise direction CCW of the driven gear 42 can be increased. Further, the support body side protruded part 28 is integrally formed with the cylindrical tube part 227 on an inner side in the radial direction of the cylindrical tube part 227 . Therefore, the strength of the support body side protruded part 28 (stopper abutted part 92 ) can be increased.
[0056] In the stopper mechanism 9 , when the driven gear 42 is turned in the counterclockwise direction CCW and the stopper abutting part (the end part 481 of the gear side protruded part 48 ) is abutted with the stopper abutted part 92 (the end part 281 of the support body side protruded part 28 ), the stopper abutted part 92 is provided at a position where the driven gear 42 is applied with a reaction force in a direction separated from the drive side gear 41 . More specifically, when the stopper mechanism 9 is operated, the stopper abutting part 91 is abutted with the stopper abutted part 92 in the first angular range θ 1 . Therefore, when the stopper mechanism 9 is operated, engagement of the drive side gear 41 with the driven gear 42 becomes shallow and thus an inertia torque in an opposite direction from the drive side gear 41 and the rotor 5 is hard to be transmitted to the driven gear 42 . Accordingly, rebounding of the driven gear 42 can be restrained and thus, when the pointer 11 is turned in the counterclockwise direction CCW toward the zero point of the pointer 11 and the zero point is indicated, the pointer 11 is hard to be shaken.
[0057] Especially, in this embodiment, in the first angular range θ 1 , the stopper abutting part 91 is abutted with the stopper abutted part 92 in an angular range of 90±60° with respect to the imaginary line “L 11 ” when viewed from the turning center of the drive side gear 41 . In addition, in this embodiment, in the first angular range θ 1 , the stopper abutting part 91 is abutted with the stopper abutted part 92 in an angular range of 90±10° with respect to the imaginary line “L 11 ” when viewed from the turning center of the drive side gear 41 . Therefore, when the stopper mechanism 9 is operated, the driven gear 42 is surely applied with a reaction force in a direction separated from the drive side gear 41 . Accordingly, engagement of the drive side gear 41 with the driven gear 42 becomes shallow and thus an inertia torque in an opposite direction from the drive side gear 41 and the rotor 5 is hard to be transmitted to the driven gear 42 . As a result, rebounding of the driven gear 42 can be restrained and thus, when the pointer 11 is turned in the counterclockwise direction CCW toward the zero point of the pointer 11 and the zero point is indicated, the pointer 11 is hard to be shaken.
[0058] In addition, the stopper mechanism 9 is structured between the driven gear 42 integrally turned with the output member 10 and the second case member 22 . Therefore, a movable range in the counterclockwise direction CCW of the output member 10 (pointer 11 ) can be directly restricted by the stopper mechanism 9 .
Other Embodiments
[0059] In the embodiment described above, the stopper mechanism 9 is provided between the second case member 22 of the case 2 (support member) and the driven gear 42 (second gear). However, the stopper mechanism 9 may be provided between the first case member 21 and the driven gear 42 (second gear).
[0060] In the embodiment described above, the stopper mechanism 9 is structured between the driven gear 42 and the second case member 22 . However, the present invention may be applied to a case that the stopper mechanism 9 is structured between the drive side gear 41 and the second case member 22 . In this case, the drive side gear 41 corresponds to the first gear in the present invention and the pinion 56 corresponds to the second gear in the present invention.
[0061] In the embodiment described above, the gear train 4 includes two gears (drive side gear 41 and driven gear 42 ) in addition to the pinion 58 . However, the present invention may be applied to a case that the gear train 4 includes two gears including the pinion 58 , or to a case that the gear train 4 includes four or more gears including the pinion 58 .
[0062] In the embodiment described above, as an example, the geared motor 100 is applied to a pointer type display device 200 . However, the present invention may be applied to a geared motor other than the geared motor 100 for a pointer type display device.
[0063] In the embodiment described above, the output member 10 and the driven gear 42 are separately provided from each other. However, the output member 10 and the driven gear 42 may be integrally formed with each other. In this case, it may be structured that a body part 44 having a larger diameter than the output member 10 is formed in a root portion of the shaft-shaped output member 10 . Alternatively, it may be structured that a shaft-shaped output member 10 is protruded from the plate-shaped part 43 and no body part 44 having a larger diameter than the output member 10 is formed in a root portion of the output member 10 . In a case that the former structure is adopted, the gear side protruded part 48 is integrally formed with the body part 44 . In a case that the latter structure is adopted, a root portion of the output member 10 corresponds to the body part 44 and the gear side protruded part 48 is integrally formed in the root portion of the output member 10 .
[0064] In the embodiment described above, the support body side protruded part 28 is integrally formed with the cylindrical tube part 227 of the second case member 22 . However, in a case that the cylindrical tube part 227 is not formed, it may be structured that the support body side protruded part 28 is integrally formed on only the end plate part 220 .
REFERENCE SIGNS LIST
[0065] 1 . . . motor part, 2 . . . case (support member), 4 . . . gear train, 5 . . . rotor, 6 . . . stator, 9 . . . stopper mechanism, 10 . . . output member, 11 . . . pointer, 21 . . . first case member, 22 . . . second case member (support member), 28 . . . support body side protruded part, 41 . . . drive side gear (second gear), 42 . . . driven gear (first gear), 43 . . . plate-shaped part, 44 . . . body part, 46 . . . plate-shaped spring, 48 . . . gear side protruded part, 58 . . . pinion, 91 . . . stopper abutting part, 92 . . . stopper abutted part, 100 . . . geared motor, 200 . . . pointer type display device, 227 . . . cylindrical tube part, 281 . . . end part of support body side protruded part, 481 . . . end part of gear side protruded part, CCW counterclockwise direction (one side in circumferential direction), CW . . . clockwise direction (one side of circumferential direction), “L” . . . turning center axial line of output member, “L 11 ” . . . imaginary line, “L 5 ” . . . rotation center axial line of drive side gear, θ 1 . . . first angular range, θ 2 . . . second angular range | The geared motor and pointer device are provided with a stopper mechanism which restricts the range of movement of the trailing-side gear when the trailing-side gear rotates in a counter-clockwise direction. In the stopper mechanism, the part to be touched by the stopper comprises a support-side protrusion which protrudes towards the center of rotation of the trailing-side gear, and the width dimension in the peripheral direction of the support-side protrusion is smaller on the inside in the radial direction than on the outside in the radial direction. As a consequence, even if the width in the peripheral direction of the support-side protrusion is increased to a certain extent in order to ensure strength, when the stopper mechanism is activated, the stopper touching part and the part to be touched by the stopper come into contact at a position close to the center of rotation of the trailing-side gear. | Summarize the information, clearly outlining the challenges and proposed solutions. | [
"FIELD OF THE INVENTION [0001] The present invention relates to a geared motor which is provided with a stopper mechanism in its gear train and a pointer type display device.",
"BACKGROUND ART [0002] In a pointer type display device and the like, a geared motor including a motor and a gear train disposed inside a case is used and a pointer is fixed to an output member of the geared motor (Patent Literature 1).",
"In Patent Literature 1, the geared motor is proposed so that a stopper mechanism is provided which is structured to stop a gear at a home position where a pointer indicates the zero point.",
"More specifically, a structure has been proposed that, in a first gear integrally turned with an output member and a second gear meshed with the first gear for driving the first gear, a gear side protruded part is provided at a substantially middle position in a radial direction of the first gear and a support member side protruded part is provided in a support member on an imaginary line passing through a turning center of the first gear and a rotation center of the second gear and, when the first gear is turned to the position where the pointer indicates the zero point, the gear side protruded part and the support member side protruded part are abutted with each other.",
"CITATION LIST Patent Literature [0003] [PTL 1] Japanese Patent Laid-Open No. 2001-327149 SUMMARY OF THE INVENTION Technical Problem [0004] However, when the pointer is returned to the home position and the gear side protruded part provided in the first gear is abutted with the support member side protruded part, the first gear is rebounded in a reverse direction to cause the pointer to be shaken.",
"In other words, in a case that the pointer is to be returned to the home position, a gear connected with the second gear, a rotor of a motor part and the like are also turned and thus, when the stopper mechanism is operated and the first gear is stopped, the second gear is also going to be stopped.",
"However, the second gear receives an inertia torque from the rotor and the like in an opposite direction and the inertia torque is transmitted to the first gear and, as a result, the first gear is rebounded.",
"[0005] Therefore, in view of the problem described above, an objective of the present invention is to provide a geared motor and a pointer type display device in which rebounding of a gear is restrained even when a stopper mechanism provided in a gear train is operated.",
"Solution to Problem [0006] To achieve the above mentioned objective, the present invention provides a geared motor including a motor part, an output member, a gear train including a plurality of gears structured to transmit rotation of the motor part to the output member, a support member which supports the motor part, the output member and the gear train, and a stopper mechanism which includes a stopper abutting part provided in a first gear of the plurality of the gears and a stopper abutted part provided in the support member and is structured so that, when the first gear is turned to one side in a circumferential direction, the stopper abutting part is abutted with the stopper abutted part to restrict a movable range of turning of the first gear to the one side.",
"The stopper abutted part is an other side end part located on the other side in the circumferential direction of a support body side protruded part which is protruded from an outer side in a radial direction toward an inner side in the radial direction and toward a turning center of the first gear, and a width dimension in the circumferential direction on an inner side in the radial direction of the support body side protruded part is set to be narrower than that on its outer side in the radial direction.",
"[0007] In the present invention, a width dimension in the circumferential direction on an inner side in the radial direction of the support body side protruded part is set to be narrower than that on its outer side in the radial direction.",
"Therefore, even in a case that the width in the circumferential direction of the support body side protruded part is set to be wide to some extent for securing strength, when the stopper mechanism is operated, the stopper abutting part and the stopper abutted part are abutted with each other at a position near the turning center axil line of the first gear.",
"Accordingly, when the stopper mechanism is operated, collision energy applied to the first gear is small and thus rebounding of the first gear can be restrained.",
"Further, a movable range to the one side of the first gear can be made wide.",
"[0008] In the present invention, it is preferable that the first gear is provided with a plate-shaped part in which teeth are formed on its outer peripheral face and a body part which is protruded from the plate-shaped part in a turning center axial line direction of the first gear at a center of the first gear, and the stopper abutting part is an one side end part located on the one side of a gear side protruded part which is integrally formed with the body part on an outer peripheral face of the body part.",
"According to this structure, the stopper abutting part (one side end part of the gear side protruded part) is abutted with the stopper abutted part at a position near the turning center axial line of the first gear.",
"Therefore, when the stopper mechanism is operated, collision energy applied to the first gear is small and thus rebounding of the first gear can be restrained.",
"[0009] In the present invention, it is preferable that the gear side protruded part is integrally formed with the plate-shaped part.",
"According to this structure, the strength of the gear side protruded part can be increased.",
"[0010] In the present invention, it is preferable that the plate-shaped part is formed with plate-shaped springs which are elastically abutted with the support member in the turning center axial line direction of the first gear at a plurality of positions in the circumferential direction, and the gear side protruded part is formed at an angular position corresponding to a portion between the plate-shaped springs adjacent to each other in the circumferential direction.",
"According to this structure, even when the plate-shaped spring is formed in the plate-shaped part of the first gear, restriction of the position for forming the gear side protruded part is small.",
"Therefore, the gear side protruded part is easily provided on an inner side in the radial direction.",
"[0011] In the present invention, it is preferable that the support member includes a cylindrical tube part with which the plate-shaped spring is abutted, and the stopper abutted part is integrally formed with the cylindrical tube part on an inner side in a radial direction of the cylindrical tube part.",
"According to this structure, the strength of the stopper abutted part can be increased.",
"[0012] In the present invention, it is preferable that the plurality of the gears includes a second gear which is meshed with the first gear to drive the first gear, and the stopper abutted part is provided at a position where the first gear is applied with a reaction force in a direction separated from the second gear when the first gear is turned to the one side and the stopper abutting part is abutted with the stopper abutted part.",
"According to this structure, when the stopper abutting part of the first gear is turned to one side in the circumferential direction and is abutted with the stopper abutted part of the support member, the first gear receives a reaction force in a direction separated from the second gear.",
"Therefore, engagement of the first gear with the second gear becomes shallow and thus an inertia torque in an opposite direction from the second gear is hard to be transmitted to the first gear.",
"Accordingly, rebounding of the first gear can be restrained.",
"[0013] In the present invention, it is preferable that a turning angular range of the first gear is divided into a first angular range and a second angular range by an imaginary line passing through a turning center of the first gear and a rotation center of the second gear and, in the first angular range where the stopper abutting part is moved in a direction coming close to the rotation center of the second gear when the first gear is turned to the one side, the stopper mechanism is structured so that the stopper abutting part is abutted with the stopper abutted part in an angular range of 90±60° with respect to the imaginary line when viewed from the rotation center of the first gear.",
"According to this structure, when the stopper abutting part is turned to one side in the circumferential direction and is abutted with the stopper abutted part of the support member, the first gear is easy to receive a reaction force in a direction separated from the second gear.",
"Therefore, engagement of the first gear with the second gear becomes shallow and thus an inertia torque in an opposite direction from the second gear is hard to be transmitted to the first gear.",
"Accordingly, rebounding of the first gear can be restrained.",
"[0014] In the present invention, it is preferable that the stopper mechanism is structured so that the stopper abutting part is abutted with the stopper abutted part in an angular range of 90±10° with respect to the imaginary line when viewed from the rotation center of the first gear.",
"According to this structure, when the stopper abutting part is turned to the one side in the circumferential direction and is abutted with the stopper abutted part of the support member, the first gear is further easily received with a reaction force in a direction separated from the second gear.",
"Therefore, engagement of the first gear with the second gear becomes further shallow and thus an inertia torque in an opposite direction from the second gear is hard to be transmitted to the first gear.",
"Accordingly, rebounding of the first gear can be restrained.",
"[0015] In the present invention, it is preferable that the first gear and the output member are integrally turned with each other.",
"According to this structure, a movable range of the output member can be directly restricted by the stopper mechanism.",
"[0016] The geared motor in accordance with the present invention may be used, for example, in a pointer type display device and, in this case, the pointer type display device has a pointer which is held by the output member.",
"In this case, it may be structured that a stopping position by the stopper mechanism corresponds to a home position of the pointer.",
"Effects of the Invention [0017] In the present invention, a width dimension in the circumferential direction on an inner side in the radial direction of the support body side protruded part is set to be narrower than that on its outer side in the radial direction.",
"Therefore, even in a case that the width in the circumferential direction of the support body side protruded part is set to be wide to some extent for securing strength, when the stopper mechanism is operated, the stopper abutting part and the stopper abutted part are abutted with each other at a position near the turning center axil line of the first gear.",
"Accordingly, when the stopper mechanism is operated, collision energy applied to the first gear is small and thus rebounding of the first gear can be restrained.",
"Further, a movable range to the one side of the first gear can be made wide.",
"BRIEF DESCRIPTION OF DRAWINGS [0018] FIGS. 1 a and 1 b are explanatory views showing a geared motor to which the present invention is applied.",
"[0019] FIG. 2 is a cross-sectional view showing a geared motor to which the present invention is applied and which is cut at a position passing a gear train.",
"[0020] FIGS. 3 a and 3 b are exploded perspective views showing a geared motor to which the present invention is applied and which is viewed from an output side.",
"[0021] FIGS. 4 a and 4 b are exploded perspective views showing a geared motor to which the present invention is applied and which is viewed from an opposite-to-output side.",
"[0022] FIGS. 5 a , 5 b and 5 c are explanatory views showing a driven gear which is used in a geared motor to which the present invention is applied.",
"[0023] FIG. 6 is an explanatory view showing a planar structure of a stopper mechanism which is structured in a geared motor to which the present invention is applied.",
"DESCRIPTION OF EMBODIMENTS [0024] A geared motor and a pointer type display device to which the present invention is applied will be described below with reference to the accompanying drawings.",
"In the following descriptions, in a direction where a turning center axial line “L”",
"of an output member 10 is extended, one side to which the output member 10 is protruded is referred to as an output side “L 1 ”",
"and an opposite side (the other side) to the side where the output member 10 is protruded is referred to as an opposite-to-output side “L 2 .”",
"Further, an axial line of a rotor 5 in a motor part 1 is a rotation center axial line “L 0 ”",
"and an axial line of a drive side gear 41 of a gear train 4 is a rotation center axial line “L 5 .”",
"Further, for convenience, the one side of each of the rotation center axial lines “L 0 ”",
"and “L 5 ”",
"is referred to as the output side “L 1 ”, and the other side of each of the rotation center axial lines “L 0 ”",
"and “L 5 ”",
"is referred to as the opposite-to-output side “L 2 .”",
"(Entire Structure of Pointer Type Display Device) [0025] FIGS. 1 a and 1 b are explanatory views showing a geared motor 100 to which the present invention is applied.",
"FIG. 1 a is a perspective view showing a geared motor 100 which is viewed from an output side “L 1 ”",
"and FIG. 1 b is a perspective view showing the geared motor 100 which is viewed from an opposite-to-output side “L 2 .”",
"FIG. 2 is a cross-sectional view showing the geared motor 100 to which the present invention is applied and which is cut at a position passing a gear train 4 .",
"FIGS. 3 a and 3 b are exploded perspective views showing the geared motor 100 to which the present invention is applied and which is viewed from an output side “L 1 .”",
"FIG. 3 a is an exploded perspective view showing a state that a second case member 22 is separated from a first case member 21 , and FIG. 3 b is an exploded perspective view showing a state that a gear train 4 and the like are detached from the first case member 21 .",
"FIGS. 4 a and 4 b are exploded perspective views showing the geared motor 100 to which the present invention is applied and which is viewed from an opposite-to-output side “L 2 .”",
"FIG. 4 a is an exploded perspective view showing a state that the first case member 21 is separated from the second case member 22 , and FIG. 4 b is an exploded perspective view showing a state that the gear train 4 and the like are detached from the second case member 22 .",
"[0026] The geared motor 100 shown in FIGS. 1 a through 4 b is structured so that a shaft-shaped output member 10 is protruded from a case 2 to the output side “L 1 ”",
"in the turning center axial line “L”",
"direction.",
"The geared motor 100 in this embodiment is used in a pointer type display device 200 and, as shown in FIG. 1 a , a pointer 11 is connected with the output member 10 .",
"[0027] The case 2 includes a first case member 21 formed in a substantially circular shape when viewed in the turning center axial line “L”",
"direction and a second case member 22 formed in a substantially circular shape when viewed in the turning center axial line “L”",
"direction.",
"The second case member 22 is overlapped with the first case member 21 from the output side “L 1 .”",
"The case 2 is a support member which supports a motor part 1 , the gear train 4 and the output member 10 described below.",
"[0028] The first case member 21 is provided with an end plate part 210 and a side plate part 211 in a tube shape which is protruded to the output side “L 1 ”",
"from an outer side edge of the end plate part 210 .",
"An outer peripheral face of the side plate part 211 is formed with a hook 219 at a plurality of positions in a circumferential direction.",
"The second case member 22 is provided with an end plate part 220 and a side plate part 221 in a tube shape which is protruded to the opposite-to-output side “L 2 ”",
"from an outer side edge of the end plate part 220 .",
"An engaging protruded part 229 is formed in the side plate part 221 at a plurality of positions in the circumferential direction.",
"Therefore, when the hooks 219 and the engaging protruded parts 229 are engaged with each other and the first case member 21 and the second case member 22 are combined with each other, the case 2 is structured.",
"In the first case member 21 , a protruded part 212 which is, for example, used for fixing the geared motor 100 is protruded toward the opposite-to-output side “L 2 ”",
"from the end plate part 210 .",
"Further, in the second case member 22 , protruded parts 222 which are, for example, used for fixing the geared motor 100 are protruded toward the output side “L 1 ”",
"from the end plate part 220 .",
"(Structure of Motor Part 1 ) [0029] The geared motor 100 includes a motor part 1 in an inside of the case 2 .",
"The motor part 1 is a drive source for the output member 10 .",
"The motor part 1 is a stepping motor which includes a rotor 5 and a stator 6 disposed around the rotor 5 .",
"The rotor 5 is rotatably supported by a support shaft 51 .",
"An end part on the opposite-to-output side “L 2 ”",
"of the support shaft 51 is held by a shaft hole 213 a formed in the end plate part 210 of the first case member 21 , and an end part on the output side “L 1 ”",
"of the support shaft 51 is held by a shaft hole 223 a formed in the end plate part 220 of the second case member 22 .",
"[0030] The rotor 5 includes a pinion 58 provided at an end part on the opposite-to-output side “L 2 ”",
"in a rotation center axial line “L 0 ”",
"direction and a magnet 50 formed in a cylindrical tube shape.",
"An “S”-pole and an “N”-pole are alternately formed at equal angular intervals on an outer peripheral face of the magnet 50 .",
"In this embodiment, the magnet 50 and the pinion 58 made of resin are integrated each other by insert molding.",
"The stator 6 includes a stator core 60 provided with a plurality of salient poles which face the outer peripheral face of the magnet 50 with a gap space therebetween.",
"A coil 8 is wound around each of two salient poles (main pole) of the plurality of the salient poles through a coil bobbin 7 .",
"The stator core 60 is formed in a plate shape and is structured by laminating a plurality of magnetic plates which are punched in a predetermined shape.",
"The stator core 60 is formed with a hole 68 through which a support shaft 410 of a drive side gear 41 described below is penetrated.",
"The coil bobbin 7 holds a plurality of terminal pins 70 to which end parts of the coil 8 are bound and connected.",
"An end part of the terminal pin 70 is protruded to the output side “L 1 ”",
"through a hole 223 d which is formed in the end plate part 220 of the second case member 22 .",
"[0031] The geared motor 100 includes a gear train 4 structured to decelerate rotation of the rotor 5 and transmit it to the output member 10 .",
"In this embodiment, the gear train 4 includes the pinion 58 , a drive side gear 41 (second gear in the present invention) meshing with the pinion 58 , and a driven gear 42 (first gear in the present invention) meshing with the drive side gear 41 .",
"The drive side gear 41 is provided with a large diameter gear 411 meshing with the pinion 58 of the rotor 5 and a small diameter gear 412 coaxially formed with the large diameter gear 411 .",
"The drive side gear 41 is rotatably supported by the support shaft 410 .",
"An end part on the opposite-to-output side “L 2 ”",
"of the support shaft 410 is held by a shaft hole 213 b formed in the end plate part 210 of the first case member 21 .",
"An end part on the output side “L 1 ”",
"of the support shaft 410 is held by a shaft hole 223 b formed in a column part 226 which is formed in the end plate part 220 of the second case member 22 .",
"The driven gear 42 is provided with a plate-shaped part 43 in a circular plate shape whose outer peripheral face is formed with outer teeth 431 meshing with the small diameter gear 412 .",
"(Structure of Driven Gear 42 ) [0032] FIGS. 5 a , 5 b and 5 c are explanatory views showing the driven gear 42 which is used in the geared motor 100 to which the present invention is applied.",
"FIG. 5 a is a perspective view showing the driven gear 42 which is viewed in an oblique direction on the output side “L 1 ”, FIG. 5 b is a plan view showing the driven gear 42 which is viewed in an oblique direction on the opposite-to-output side “L 2 ”, and FIG. 5 c is a side view showing the driven gear 42 .",
"[0033] The driven gear 42 is a final gear structured to transmit its rotation to the output member 10 and to be integrally turned with the output member 10 .",
"The driven gear 42 is structured as described below.",
"[0034] In FIGS. 5 a , 5 b and 5 c , the driven gear 42 is provided with a shaft-shaped body part 44 , which is protruded from the center of the plate-shaped part 43 to the output side “L 1 ”, and a circular protruded part 45 which is protruded from the center of the plate-shaped part 43 to the opposite-to-output side “L 2 .”",
"A shaft hole 440 , i.e., a through hole into which the output member 10 is fitted is provided in the body part 44 and the circular protruded part 45 .",
"The driven gear 42 and the output member 10 are integrally turned with each other.",
"[0035] The plate-shaped part 43 is formed with a groove 47 which penetrates the plate-shaped part 43 in the turning center axial line “L”",
"direction.",
"The groove 47 is extended to one side around the turning center axial line “L”",
"and then bent in a “U”-shape and extended to the other side in the circumferential direction.",
"As a result, a portion of the plate-shaped part 43 which is surrounded by the groove 47 is formed to be a plate-shaped spring 46 whose one end in the circumferential direction is connected with the plate-shaped part 43 .",
"A protruded part 461 protruded toward the output side “L 1 ”",
"is formed on a tip end side of the plate-shaped spring 46 .",
"In this embodiment, the plate-shaped spring 46 is formed at two positions with equal angular intervals in the circumferential direction so as to extend in the same direction.",
"An angular interval of two plate-shaped springs 46 is 180°.",
"[0036] The plate-shaped part 43 is formed with a gear side protruded part 48 protruded to the output side “L 1 ”",
"and to an outer side in a radial direction at an angular position between two plate-shaped springs 46 in the circumferential direction.",
"The gear side protruded part 48 structures a stopper mechanism 9 which restricts a movable range when the driven gear 42 is turned in a counterclockwise direction “CCW”",
"(one side in the circumferential direction) by abutting with a support body side protruded part 28 described below.",
"(Support Structure for Driven Gear 42 and Output Member 10 ) [0037] As shown in FIGS. 3 a through 4 b , the end plate part 210 of the first case member 21 is formed with a cylindrical tube part 215 protruded to the output side “L 1 ”",
"and a cylindrical tube part 216 protruded to the opposite-to-output side “L 2 .”",
"The cylindrical tube parts 215 and 216 are formed with shaft holes 215 a and 216 a which turnably support an opposite-to-output side end part of the output member 10 .",
"[0038] On the other hand, the end plate part 220 of the second case member 22 is formed with a cylindrical tube part 225 which is protruded to the output side “L 1 .”",
"The cylindrical tube part 225 is formed with a shaft hole 225 a which turnably supports an output side portion of the output member 10 .",
"[0039] A face on the opposite-to-output side “L 2 ”",
"of the end plate part 220 of the second case member 22 is formed with a cylindrical tube part 227 into which the body part 44 of the driven gear 42 is entered and plate-shaped ribs 224 which are extended from the cylindrical tube part 227 toward outer sides in a radial direction.",
"An inner diameter of the cylindrical tube part 227 is larger than an outer diameter of the body part 44 of the driven gear 42 , and an inner face of the cylindrical tube part 227 does not contact with the body part 44 of the driven gear 42 .",
"The ribs 224 are formed at four positions with equal angular intervals around the cylindrical tube part 227 .",
"Three ribs 224 a , 224 b and 224 c of four ribs 224 are connected with the side plate part 221 and the remaining one rib 224 d is connected with the column part 226 formed with the shaft hole 223 b. [0040] In this embodiment, the circular protruded part 45 of the driven gear 42 is abutted with the cylindrical tube part 215 of the first case member 21 and movement of the driven gear 42 to the opposite-to-output side “L 2 ”",
"is prevented.",
"Further, the protruded parts 461 of the plate-shaped springs 46 of the driven gear 42 are elastically abutted with an end face on the opposite-to-output side “L 2 ”",
"of the cylindrical tube part 227 of the second case member 22 and movement of the driven gear 42 to the output side “L 1 ”",
"is restricted.",
"Therefore, the driven gear 42 and the output member 10 are restrained from rattling in the turning center axial line “L”",
"direction.",
"(Operations) [0041] In the geared motor 100 and the pointer type display device 200 structured as described above, when electrical power is supplied to the coil 8 through the terminal pins 70 in a state that the pointer 11 is stopped at the zero point (home position), the rotor 5 is rotated and the rotation is transmitted to the output member 10 through the gear train 4 .",
"Therefore, the pointer 11 connected with the output member 10 is turned in the clockwise direction CW.",
"In this case, an angular position of the pointer 11 is changed by inputting a predetermined number of drive pulses into the coil 8 and, after the pointer 11 is turned to a target position in the clockwise direction CW, the pointer 11 is stopped.",
"Further, when drive pulses for reverse rotation are supplied, the pointer can be turned in the counterclockwise direction CCW to another target position.",
"(Structure of Stopper Mechanism) [0042] FIG. 6 is an explanatory view showing a planar structure of a stopper mechanism 9 which is structured in the geared motor 100 to which the present invention is applied.",
"In FIG. 6 , the gear train 4 is shown by the solid line and the second case member 22 is shown by the alternate long and short dash line.",
"[0043] In FIG. 6 , in the geared motor 100 in this embodiment, a stopper mechanism 9 is structured between the driven gear 42 and the second case member 22 (support member) so that, when the pointer 11 shown in FIG. 1 a is turned in the counterclockwise direction CCW and reached to the home position indicating the zero point, a stopper abutting part 91 provided in the driven gear 42 is abutted with a stopper abutted part 92 provided in the second case member 22 to restrict a movable range in the counterclockwise direction CCW (to one side around the turning center axial line “L”) of the driven gear 42 .",
"[0044] In this embodiment, the driven gear 42 is provided with a gear side protruded part 48 protruding toward an outer side in the radial direction on an outer peripheral face of the body part 44 which is protruded to the output side “L 1 ”",
"from the plate-shaped part 43 at the center of the driven gear 42 .",
"The stopper abutting part 91 is structured by an end part 481 (one side end part) which is located on the counterclockwise direction “CCW”",
"side of the gear side protruded part 48 .",
"The gear side protruded part 48 is integrally formed with the body part 44 and is also integrally formed with the plate-shaped part 43 .",
"[0045] In this embodiment, the plate-shaped part 43 is formed with the plate-shaped spring 46 and the groove 47 at two positions in the circumferential direction, and the gear side protruded part 48 is formed at an angular position corresponding to a portion between the plate-shaped springs 46 adjacent to each other in the circumferential direction.",
"Therefore, although an end part on an outer side in the radial direction of the gear side protruded part 48 is located on an outer side in the radial direction with respect to a portion on an inner side in the radial direction of the groove 47 , since the gear side protruded part 48 and the groove 47 are displaced from each other in the circumferential direction, the gear side protruded part 48 and the body part 44 can be integrally formed with each other.",
"In this embodiment, the gear side protruded part 48 is formed in a planar shape in which a width dimension in the circumferential direction on its inner side in the radial direction is shorter than a width dimension in the circumferential direction on its outer side in the radial direction.",
"Therefore, a rotatable angular range of the driven gear 42 is wide.",
"However, it may be structured that a width dimension in the circumferential direction on an inner side in the radial direction of the gear side protruded part 48 and a width dimension in the circumferential direction on its outer side in the radial direction are equal to each other, or that a width dimension in the circumferential direction on its inner side in the radial direction is longer than a width dimension in the circumferential direction on its outer side in the radial direction.",
"[0046] The second case member 22 is provided with a support body side protruded part 28 which is protruded from the end plate part 220 to the opposite-to-output side “L 2 .”",
"The stopper abutted part 92 is structured by an end part 281 (the other side end part) on a side in the clockwise direction CW of the support body side protruded part 28 (the other side around the turning center axial line “L”).",
"In this embodiment, the support body side protruded part 28 is protruded from an inner peripheral face of the cylindrical tube part 227 toward the turning center axial line “L”",
"of the driven gear 42 on an inner side of the cylindrical tube part 227 , and an end part on an outer side in the radial direction of the support body side protruded part 28 and the inner peripheral face of the cylindrical tube part 227 are connected with each other.",
"[0047] In this embodiment, the support body side protruded part 28 is provided with a planar shape having a substantially trapezoid and a width dimension in the circumferential direction on its inner side in the radial direction is narrower than that on its outer side in the radial direction.",
"In other words, the support body side protruded part 28 is protruded from the inner peripheral face of the cylindrical tube part 227 to the inner side in the radial direction along an extended line of the rib 224 a on the inner side of the cylindrical tube part 227 .",
"In this case, a width dimension “W 1 ”",
"on the outer side in the radial direction of the support body side protruded part 28 is substantially equal to a width dimension of the rib 224 a .",
"However, a width dimension “W 2 ”",
"on its inner side in the radial direction is set to be narrower than the width dimension of the rib 224 a .",
"In other words, the width dimension “W 1 ”",
"on the outer side in the radial direction of the support body side protruded part 28 and the width dimension “W 2 ”",
"on its inner side in the radial direction are set in the following relationship: [0048] the width dimension “W 1 ”>the width dimension “W 2 .”",
"[0049] Further, the stopper abutted part 92 (end part 281 of the support body side protruded part 28 ) is provided at a position where the driven gear 42 receives a reaction force in a direction separated from the drive side gear 41 when the driven gear 42 is turned in the counterclockwise direction CCW and the stopper abutting part 91 (end part 481 of the gear side protruded part 48 ) is abutted with the stopper abutted part 92 .",
"More specifically, when a turning angle range of the driven gear 42 is divided into a first angular range θ 1 and a second angular range θ 2 by an imaginary line “L 11 ”",
"passing through a turning center of the driven gear 42 (turning center axial line “L”) and a rotation center of the drive side gear 41 (rotation center axial line “L 5 ”), the stopper abutted part 92 (end part 281 of the support body side protruded part 28 ) is disposed in the first angular range θ 1 in which the stopper abutting part 91 is moved in a direction so as to come close to the rotation center of the drive side gear 41 when the driven gear 42 is turned in the counterclockwise direction CCW.",
"[0050] Further, the stopper abutted part 92 is provided in an angular range of 90±60° with respect to the imaginary line “L 11 ”",
"when viewed from the turning center of the driven gear 42 .",
"Especially, in this embodiment, the stopper abutted part 92 is provided in an angular range of 90±10° with respect to the imaginary line “L 11 ”",
"when viewed from the turning center of the driven gear 42 .",
"Therefore, when the driven gear 42 is turned in the counterclockwise direction CCW and the stopper abutting part (end part 481 of the gear side protruded part 48 ) is abutted with the stopper abutted part 92 , the driven gear 42 is surely received with a reaction force in a direction separated from the drive side gear 41 .",
"Principal Effects in this Embodiment [0051] As described above, in the geared motor 100 and the pointer type display device 200 in this embodiment, the stopper mechanism 9 is provided which determines a movable range of the driven gear 42 when the driven gear 42 (output member 10 ) is turned in the counterclockwise direction CCW.",
"Therefore, the position of the pointer 11 indicating the zero point can be determined in which the position where the stopper mechanism 9 is operated is determined as a home position of the driven gear 42 .",
"[0052] In this embodiment, in the stopper abutting part 91 and the stopper abutted part 92 which structure the stopper mechanism 9 , the stopper abutting part 91 is an end part 481 of the gear side protruded part 48 which is integrally formed with the body part 44 on an outer peripheral face of the body part 44 of the driven gear 42 .",
"Therefore, the stopper abutting part 91 is abutted with the stopper abutted part 92 at a position near the turning center axial line “L”",
"of the driven gear 42 .",
"Accordingly, when the stopper mechanism 9 is operated, collision energy received by the driven gear 42 is small and thus rebounding of the driven gear 42 can be restrained.",
"As a result, when the driven gear 42 is turned in the counterclockwise direction CCW toward the zero point of the pointer 11 and the zero point is indicated, the pointer 11 is hard to be shaken.",
"Further, the gear side protruded part 48 is integrally formed with the plate-shaped part 43 of the driven gear 42 and thus the strength of the gear side protruded part 48 can be increased.",
"[0053] The plate-shaped part 43 is formed with the plate-shaped springs 46 at a plurality of positions in the circumferential direction and the gear side protruded part 48 is formed at an angular position corresponding to a portion between the plate-shaped springs 46 adjacent to each other in the circumferential direction.",
"Therefore, even when the plate-shaped springs 46 are formed in the plate-shaped part 43 , restriction of the position for forming the gear side protruded part 48 is reduced.",
"Accordingly, the gear side protruded part 48 is easily provided on an inner side in the radial direction.",
"[0054] On the other hand, the stopper abutted part 92 is the end part 281 of the support body side protruded part 28 which is protruded toward the turning center of the driven gear 42 from an outer side in the radial direction to an inner side in the radial direction, and a width dimension in the circumferential direction of the support body side protruded part 28 on the inner side in the radial direction is narrower than that on its outer side in the radial direction.",
"Therefore, even in a case that the width in the circumferential direction of the support body side protruded part 28 is set to be wide to some extent for securing strength, when the stopper mechanism 9 is operated, the stopper abutting part 91 and the stopper abutted part 92 are abutted with each other at a position which is near to the turning center of the driven gear 42 .",
"Therefore, when the stopper mechanism 9 is operated, collision energy applied to the driven gear 42 is small and thus rebounding of the driven gear 42 can be restrained.",
"Accordingly, when the pointer 11 is turned in the counterclockwise direction CCW toward the zero point of the pointer 11 and the zero point is indicated, the pointer 11 is hard to be shaken.",
"[0055] The width dimension in the circumferential direction of the support body side protruded part 28 is narrower on an inner side in the radial direction than that on its outer side in the radial direction and thus a movable range in the counterclockwise direction CCW of the driven gear 42 can be increased.",
"Further, the support body side protruded part 28 is integrally formed with the cylindrical tube part 227 on an inner side in the radial direction of the cylindrical tube part 227 .",
"Therefore, the strength of the support body side protruded part 28 (stopper abutted part 92 ) can be increased.",
"[0056] In the stopper mechanism 9 , when the driven gear 42 is turned in the counterclockwise direction CCW and the stopper abutting part (the end part 481 of the gear side protruded part 48 ) is abutted with the stopper abutted part 92 (the end part 281 of the support body side protruded part 28 ), the stopper abutted part 92 is provided at a position where the driven gear 42 is applied with a reaction force in a direction separated from the drive side gear 41 .",
"More specifically, when the stopper mechanism 9 is operated, the stopper abutting part 91 is abutted with the stopper abutted part 92 in the first angular range θ 1 .",
"Therefore, when the stopper mechanism 9 is operated, engagement of the drive side gear 41 with the driven gear 42 becomes shallow and thus an inertia torque in an opposite direction from the drive side gear 41 and the rotor 5 is hard to be transmitted to the driven gear 42 .",
"Accordingly, rebounding of the driven gear 42 can be restrained and thus, when the pointer 11 is turned in the counterclockwise direction CCW toward the zero point of the pointer 11 and the zero point is indicated, the pointer 11 is hard to be shaken.",
"[0057] Especially, in this embodiment, in the first angular range θ 1 , the stopper abutting part 91 is abutted with the stopper abutted part 92 in an angular range of 90±60° with respect to the imaginary line “L 11 ”",
"when viewed from the turning center of the drive side gear 41 .",
"In addition, in this embodiment, in the first angular range θ 1 , the stopper abutting part 91 is abutted with the stopper abutted part 92 in an angular range of 90±10° with respect to the imaginary line “L 11 ”",
"when viewed from the turning center of the drive side gear 41 .",
"Therefore, when the stopper mechanism 9 is operated, the driven gear 42 is surely applied with a reaction force in a direction separated from the drive side gear 41 .",
"Accordingly, engagement of the drive side gear 41 with the driven gear 42 becomes shallow and thus an inertia torque in an opposite direction from the drive side gear 41 and the rotor 5 is hard to be transmitted to the driven gear 42 .",
"As a result, rebounding of the driven gear 42 can be restrained and thus, when the pointer 11 is turned in the counterclockwise direction CCW toward the zero point of the pointer 11 and the zero point is indicated, the pointer 11 is hard to be shaken.",
"[0058] In addition, the stopper mechanism 9 is structured between the driven gear 42 integrally turned with the output member 10 and the second case member 22 .",
"Therefore, a movable range in the counterclockwise direction CCW of the output member 10 (pointer 11 ) can be directly restricted by the stopper mechanism 9 .",
"Other Embodiments [0059] In the embodiment described above, the stopper mechanism 9 is provided between the second case member 22 of the case 2 (support member) and the driven gear 42 (second gear).",
"However, the stopper mechanism 9 may be provided between the first case member 21 and the driven gear 42 (second gear).",
"[0060] In the embodiment described above, the stopper mechanism 9 is structured between the driven gear 42 and the second case member 22 .",
"However, the present invention may be applied to a case that the stopper mechanism 9 is structured between the drive side gear 41 and the second case member 22 .",
"In this case, the drive side gear 41 corresponds to the first gear in the present invention and the pinion 56 corresponds to the second gear in the present invention.",
"[0061] In the embodiment described above, the gear train 4 includes two gears (drive side gear 41 and driven gear 42 ) in addition to the pinion 58 .",
"However, the present invention may be applied to a case that the gear train 4 includes two gears including the pinion 58 , or to a case that the gear train 4 includes four or more gears including the pinion 58 .",
"[0062] In the embodiment described above, as an example, the geared motor 100 is applied to a pointer type display device 200 .",
"However, the present invention may be applied to a geared motor other than the geared motor 100 for a pointer type display device.",
"[0063] In the embodiment described above, the output member 10 and the driven gear 42 are separately provided from each other.",
"However, the output member 10 and the driven gear 42 may be integrally formed with each other.",
"In this case, it may be structured that a body part 44 having a larger diameter than the output member 10 is formed in a root portion of the shaft-shaped output member 10 .",
"Alternatively, it may be structured that a shaft-shaped output member 10 is protruded from the plate-shaped part 43 and no body part 44 having a larger diameter than the output member 10 is formed in a root portion of the output member 10 .",
"In a case that the former structure is adopted, the gear side protruded part 48 is integrally formed with the body part 44 .",
"In a case that the latter structure is adopted, a root portion of the output member 10 corresponds to the body part 44 and the gear side protruded part 48 is integrally formed in the root portion of the output member 10 .",
"[0064] In the embodiment described above, the support body side protruded part 28 is integrally formed with the cylindrical tube part 227 of the second case member 22 .",
"However, in a case that the cylindrical tube part 227 is not formed, it may be structured that the support body side protruded part 28 is integrally formed on only the end plate part 220 .",
"REFERENCE SIGNS LIST [0065] 1 .",
"motor part, 2 .",
"case (support member), 4 .",
"gear train, 5 .",
"rotor, 6 .",
"stator, 9 .",
"stopper mechanism, 10 .",
"output member, 11 .",
"pointer, 21 .",
"first case member, 22 .",
"second case member (support member), 28 .",
"support body side protruded part, 41 .",
"drive side gear (second gear), 42 .",
"driven gear (first gear), 43 .",
"plate-shaped part, 44 .",
"body part, 46 .",
"plate-shaped spring, 48 .",
"gear side protruded part, 58 .",
"pinion, 91 .",
"stopper abutting part, 92 .",
"stopper abutted part, 100 .",
"geared motor, 200 .",
"pointer type display device, 227 .",
"cylindrical tube part, 281 .",
"end part of support body side protruded part, 481 .",
"end part of gear side protruded part, CCW counterclockwise direction (one side in circumferential direction), CW .",
"clockwise direction (one side of circumferential direction), “L”",
"turning center axial line of output member, “L 11 ”",
"imaginary line, “L 5 ”",
"rotation center axial line of drive side gear, θ 1 .",
"first angular range, θ 2 .",
"second angular range"
] |
PRIORITY
[0001] This application is a continuation under 35 U.S.C. §120 of U.S. patent application Ser. No. 13/290,931 filed on 7 Nov. 2011, which is a continuation under 35 U.S.C. §120 of U.S. patent application Ser. No. 12/255,998 filed on 22 Oct. 2008, now U.S. Pat. No. 8,054,090, each of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to noise handling in a capacitive touch sensor for detecting proximity of a body, more especially to a capacitive sensor of the so-called active type which is based on measuring the capacitive coupling between a drive and a sense electrode.
[0003] There are various forms of touch sensitive controls which use a capacitive sensor to sense the presence of a body such as a user's finger. A form of touch sensitive control is disclosed in WO-00/44018. In this example a pair of electrodes are provided which act as a key so that the presence of a body such as a user's finger is detected as a result of a change in an amount of charge which is transferred between the two electrodes. With this arrangement, one of the electrodes (labeled X) is driven with a drive circuit and the other of the pair of electrodes (labeled Y) is connected to a charge measurement circuit which detects an amount of charge present on the Y plate when driven by the X plate. As disclosed in WO-00/44018 several pairs of electrodes can be arranged to form a matrix of sensing areas which can provide an efficient implementation of a touch sensitive two-dimensional position sensor. Such two dimensional capacitive transducing (2DCT) sensors are typically used with devices which include touch sensitive screens or touch sensitive keyboards/keypads which are used in for example in consumer electronic devices and domestic appliances.
[0004] Devices employing 2DCT sensors have become increasingly popular and common not only in conjunction with personal computers but also in all manner of other appliances such as personal digital assistants (PDAs), point of sale (POS) terminals, electronic information and ticketing kiosks, kitchen appliances and the like. 2DCT sensors are frequently preferred to mechanical switches for a number of reasons. For example, 2DCT sensors require no moving parts and so are less prone to wear than their mechanical counterparts. 2DCT sensors can also be made in relatively small sizes so that correspondingly small, and tightly packed keypad arrays can be provided. Furthermore, 2DCT sensors can be provided beneath an environmentally sealed outer surface/cover panel. This makes their use in wet environments or where there is a danger of dirt or fluids entering a device being controlled attractive. In addition, manufactures often prefer to employ interfaces based on 2DCT sensors in their products because such interfaces are often considered by consumers to be more aesthetically pleasing than conventional mechanical input mechanisms (e.g. push-buttons).
[0005] Other devices which may incorporate 2DCT sensors include pen-input tablets and encoders used in machinery for feedback control purposes, for example 2DCT sensors are capable of reporting at least a 2-dimensional coordinate, Cartesian or otherwise, related to the location of an object or human body part by means of a capacitance sensing mechanism.
[0006] Although touch sensitive capacitive sensors such as those described above and disclosed in the above-mentioned disclosures have been successfully deployed in many applications, some applications can present a challenging environment for detecting a change in charge as a result of the presence of a body.
[0007] For example, the use of a touch sensor on a mobile phone can create a technical problem because there is a variety of disturbing noise signals produced by radio frequency radiation by radio frequency signals and by modulators within the mobile phone. Similarly, a liquid crystal display (LCD) has characteristic switching noise as a result of switching and refreshing pixels. Other types of display may have their own forms of characteristic impulsive noise related to pixel scanning and refresh. Sinusoidal noise, such as that produced by mains electricity may also be present, which can affect the amount of charge detected on a key. This may be significant, for example, when a hand held device such as a mobile telephone is being charged through the mains.
[0008] FIG. 7 of the accompanying drawings shows an example of sinusoidal noise in the form of a plot of signal strength or amplitude which may be voltage or charge measured with respect to time. Various points 220 are shown to indicate points at which burst measurements are taken for a touch sensor such as those described above. As will be appreciated, as a result of sinusoidal noise represented by a line 222 , an amount of charge transferred from a key by a measurement capacitor of the measurement circuit such as those described above will vary and therefore could in some circumstances cause a false measurement of the presence of a body.
[0009] FIG. 8 of the accompanying drawings shows another form of noise, namely rectangular or impulsive noise, i.e. noise having high frequency components, such as that which might be produced by switching the pixels in a LCD display with which the touch panel is integrated. A plot of signal strength with respect to time is shown with sampling points 220 , which might be produced by bursts of measurement cycles in a measurement circuit such as those described above. Noise impulses 222 are also shown. If a measurement cycle coincides with a rising edge of a noise impulse, as may arise from an LCD switching event, then an erroneous measurement can be produced which can again cause a touch sensor to erroneously detect the presence of a body.
[0010] FIG. 9 of the accompanying drawings illustrates this situation showing simultaneous sinusoidal and rectangular noise. As will be appreciated, in general, both sinusoidal noise and rectangular noise may be present during a given time period. Moreover, by its nature, the amount of noise as well as its frequency components will often vary over time.
[0011] Prior art capacitive sensors adopt a variety of signal processing techniques to filter noise from the acquired signals. For example, boxcar averagers and detection integrators have been used in the past. In principle other types of standard filtering could be used, and may have been used, such as slew rate filters, high frequency pass filters, low frequency pass filters and band pass filters.
[0012] It is desirable to tailor the filtering depending on how noisy the signals arc. For example, it may be desirable to switch certain filters on and off depending on the amount and characteristics of noise, or to set parameters of filters having regard to the noise.
SUMMARY OF THE INVENTION
[0013] The invention provides a method of measuring proximity of a body to a capacitive sensor device comprising a coupling capacitor having a capacitance sensitive to proximity of a body, and a charge accumulation capacitor having first and second plates, the first plate being connected to the coupling capacitor, and the second plate being connected to a voltage output line.
[0014] A signal measurement is made conventionally by transferring charge indicative of the capacitance of the coupling capacitor from the coupling capacitor to the charge accumulation capacitor, and by reading the voltage on the voltage output line, thereby to measure proximity of a body.
[0015] An additional noise measurement is made, either before or after the signal measurement, by emulating or mimicking the signal measurement, but inhibiting charge from arising on the coupling capacitor as a result of proximity of a body, thereby to transfer charge indicative of noise induced on the coupling capacitor to the charge accumulation capacitor, and by reading the voltage on the voltage output line, thereby to measure noise.
[0016] In a preferred embodiment, a method of measuring proximity of a body to a capacitive sensor device is provided, the capacitive sensor device comprising X and Y electrodes forming respective X and Y plates of a coupling capacitor having a capacitance sensitive to proximity of a body, and a charge accumulation capacitor having first and second plates, the first plate being connected to the Y plate of the coupling capacitor, and the second plate being connected to a voltage output line, the method comprising: making a signal measurement by applying one or more cycles of driving the X electrode with an input voltage, thereby to transfer one or more packets of charge indicative of the capacitance of the coupling capacitor from the coupling capacitor to the charge accumulation capacitor, and by reading the voltage on the voltage output line, thereby to measure proximity of a body; and making a noise measurement, either before or after the signal measurement, by emulating or mimicking the signal measurement, but without driving the X electrode, thereby to transfer one or more packets of charge indicative of noise induced on the coupling capacitor to the charge accumulation capacitor, and by reading the voltage on the voltage output line, thereby to measure noise.
[0017] A noise measurement can therefore be obtained whenever desired, for example after every ‘n’ signal measurements, wherein the noise measurement is taken directly from the coupling capacitors that form the sensing nodes of the capacitive sensor device. The noise measurements should therefore be representative of noise levels when the signal measurements are made, since they are obtained using the same circuit elements and interconnects. Moreover, the noise measurements can be made without any additional hardware requirement on the sensor device.
[0018] The second plate of the charge accumulation capacitor is preferably connected to a pre-charge line operable to inject a predetermined amount of charge onto the second plate When making the noise measurement, the second plate of the charge accumulation capacitor is then charged before mimicking the signal measurement, thereby to measure noise through its modulation of the amount of charge initially placed on the charge accumulation capacitor. The pre-charge makes the amount of charge accumulated on the charge accumulation capacitor independent of the sign of the charge induced on the Y plate of the coupling capacitor at each cycle of the noise measurement process. This is useful if the controller is not capable of measuring arbitrary voltages from the charge accumulation capacitor. For example, if the controller does not use an analog to digital converter to read off the voltage, but rather a comparator only capable of detecting zero crossings, then the second plate of the charge accumulation capacitor can be pre-charged, e.g. to a certain negative or positive voltage, to ensure that noise contributions will not cause the voltage to change sign before read out, but rather only modulate the pre-charge voltage without changing its sign.
[0019] In the noise measurement, charge may be transferred to the charge accumulation capacitor in a plurality of cycles, and the voltage on the voltage output line is read after a predetermined number of said cycles. In order that the noise is not averaged out on the charge accumulation capacitor, the number of cycles is preferably 1, or a small integer number such as 2, 3, 4 or 5.
[0020] In the signal measurement, charge may be transferred to the charge accumulation capacitor in a plurality of cycles, and the voltage on the voltage output line is read after a predetermined number of said cycles. Alternatively, charge may be transferred to the charge accumulation capacitor in a plurality of cycles, wherein the cycles are repeated until the voltage on the voltage output line reaches a threshold value, the number of cycles required to reach the threshold value being read as the measure of the capacitance. In the signal measurement, the number of predetermined cycles could be 1, but is preferably a higher number so that the charge accumulation capacitor has an averaging effect on any noise. For example, the number of cycles is preferably at least 5, 10, 20, 30, 40, 50 or 100. The number of cycles over which charge is transferred from the coupling capacitor to the charge accumulation capacitor is often referred to in the art as the burst length.
[0021] It will thus be appreciated that the noise measurement will typically use short fixed burst lengths, e.g. of only cycle or a few cycles, whereas the signal measurement will typically use longer burst lengths, which may be fixed, i.e. predetermined in number, or variable, i.e. the number required for the signal to reach a threshold value. Consequently the burst length for the noise measurement will typically be shorter than the burst length for the signal measurement.
[0022] The method is applied by interspersing signal measurements and noise measurements. Typically, a plurality of signal measurements are made for each noise measurement. The noise measurements may be limited so that they only occupy a certain minority of the total measurement time, for example a noise measurement may be made after ‘n’ signal measurements, where n might be at least 2, 3, 4, 5, 10, 20, 50 or 100. In a 2DCT, a noise measurement might be made once per frame or once every ‘n’ frames, where collection of a frame of touch data is defined as reading a signal measurement from each of the sensing nodes, i.e. each of the coupling capacitors, of the two-dimensional touch panel.
[0023] The invention also provides a capacitive sensor device comprising a coupling capacitor having a capacitance sensitive to proximity of a body, and a charge accumulation capacitor having first and second plates, the first plate being connected to the coupling capacitor, and the second plate being connected to a voltage output line, the device being operable in a first mode to make a signal measurement by transferring charge indicative of the capacitance of the coupling capacitor from the coupling capacitor to the charge accumulation capacitor, wherein the voltage on the voltage output line is a measure of proximity of a body; and the device being operable in a second mode to make a noise measurement by mimicking the signal measurement, but without enabling charge to arise on the coupling capacitor through proximity of a body, thereby to transfer charge indicative of noise induced on the coupling capacitor to the charge accumulation capacitor, wherein the voltage on the voltage output line is a measure of noise.
[0024] In a preferred embodiment the invention further provides a capacitive sensor device comprising X and Y electrodes forming respective X and Y plates of a coupling capacitor having a capacitance sensitive to proximity of a body, and a charge accumulation capacitor having first and second plates, the first plate being connected to the Y plate of the coupling capacitor, and the second plate being connected to a voltage output line, the device being operable in a first mode to make a signal measurement by applying successive cycles of driving the X electrode with an input voltage, thereby to transfer successive packets of charge indicative of the capacitance of the coupling capacitor from the coupling capacitor to the charge accumulation capacitor, wherein the voltage on the voltage output line is a measure of proximity of a body; and the device being operable in a second mode to make a noise measurement by mimicking the signal measurement, but without driving the X electrode, thereby to transfer successive packets of charge indicative of noise induced on the coupling capacitor to the charge accumulation capacitor, wherein the voltage on the voltage output line is a measure of noise.
[0025] The second plate of the charge accumulation capacitor is preferably connected to a pre-charge line operable to inject a predetermined amount of charge onto the second plate, and wherein, in the noise measurement mode, the second plate of the charge accumulation capacitor is pre-charged before mimicking the signal measurement, thereby to measure noise through its modulation of the amount of charge initially placed on the charge accumulation capacitor by the pre-charge.
[0026] The invention provides benefit to single element touch sensor devices, i.e. devices with one or more isolated buttons, as well as to one-dimensional sensors, such as sliders or scroll wheels, and also to two-dimensional sensors, such as alphanumeric key pad emulators and overlays for displays which thereby provide touch screens.
[0027] In some embodiments, the device has a plurality of Y electrodes common to each X electrode. In addition, each Y electrode may have its own charge accumulator capacitor. Alternatively, these could be shared through a multiplexer. In a two-dimensional sensor there may be a plurality of X electrodes, and the X and Y electrodes may be arranged to form a two-dimensional array of coupling capacitors distributed over a touch sensitive panel.
[0028] The device may further comprise a data acquisition unit, such as a microcontroller or other processor, connected to the voltage output line and operable to measure the voltage on the voltage output line to acquire the signal and noise measurements. The device may still further comprise a filter operable to perform numerical processing on the signal measurements, wherein the filter is operable having regard to the noise measurements. The filter may be hosted by the data acquisition unit and provide signal processing in advance of the signal measurements being supplied to higher level systems components. Alternatively, the filter may be hosted in a higher level system component, such as a central processing unit or digital signal processor. The filter preferably has configuration settings that are modified depending on the noise measurements, e.g. a bandpass filter may have its bandpass range changed, a slew filter may have its increment/decrement coefficients changed. Moreover, the noise measurement may govern whether the filter is applied, for example if noise levels are measured to be low, then the filter may be deactivated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] For a better understanding of the invention, and to show how the same may be carried into effect, reference is now made by way of example to the accompanying drawings, in which:
[0030] FIG. 1 a is a schematic block diagram of a touch sensing node, and FIG. 1 b is an example illustration of a user's finger disposed proximate the sensor of FIG. 1 a;
[0031] FIG. 2 is a schematic block diagram illustrating an electrical equivalent of the touch sensor shown in FIG. 1 b;
[0032] FIG. 3 is a schematic block diagram of a touch sensing circuit for use with the touch sensing node of FIG. 1 a and FIG. 1 b;
[0033] FIG. 4 is an example timing diagram illustrating the operation of the sensing circuit shown in FIG. 3 ;
[0034] FIG. 5 is a circuit diagram illustrating a touch sensitive matrix providing a two-dimensional capacitive transducing sensor arrangement according to an embodiment of the invention;
[0035] FIG. 6 is a tinning diagram illustrating the operation of the sensing circuit shown in FIG. 3 according an embodiment of the invention;
[0036] FIG. 7 is a plot of signal strength with respect to time representing a voltage or charge present on a sensing key which has been affected by sinusoidal noise, such as mains noise;
[0037] FIG. 8 is a plot of signal strength with respect to time representing the voltage or charge on a sensing key in the presence of rectangular noise, such as LCD noise; and
[0038] FIG. 9 is a plot of signal strength with respect to time representing the voltage or charge on a sensing key in the presence of sinusoidal and rectangular noise.
DETAILED DESCRIPTION OF THE INVENTION
[0039] FIG. 1 a is a schematic cross-section through a touch sensitive control panel 15 in the absence of an actuating body, typically a user's finger or stylus.
[0040] FIG. 1 b corresponds to FIG. 1 a , but shows the same cross-section in the presence of an actuating body in the form of a user's finger.
[0041] The touch sensor shown in FIGS. 1 a and 1 b corresponds to an example in which a pair of transverse electrodes form a touch sensor. As shown in FIG. 1 a a pair of electrodes 100 , 104 which form a drive or X plate and a receiving or Y plate in the following description are disposed beneath the surface of a touch sensitive control panel 15 . The electrodes 100 , 104 are disposed beneath a dielectric layer 16 , for example a glass or plastics panel. As shown in FIGS. 1 a and 1 b the touch sensor 10 is arranged to detect the presence of a body such as a user's finger 20 as a result of a change in an amount of charge transferred from the Y plate 104 . As shown in FIG. 1 a when the X plate 100 is charged or driven by a circuit, an electric field is formed which is illustrated by the lines 18 and 19 both above and below the touch panel surface 15 as a result of which charge is transferred to the Y plate 104 . The X plate and the Y plate 100 , 104 form a capacitively chargeable sensing node 10 , referred to as a key in the following. As shown in FIG. 1 b as a result of the disturbance of the electric field 18 due to the presence of the user's finger 20 the electric field above the surface of the control panel 15 is disturbed as a result of an earthing or grounding effect provided by the user's finger 20 as illustrated schematically by ground 34 .
[0042] An equivalent circuit diagram of the touch sensor shown in FIGS. 1 a and 1 b is shown in FIG. 2 . In FIG. 2 equivalent capacitances are illustrated in the form of a circuit diagram. A capacitance limited between the X plate 100 and the Y plate 104 of the key is a capacitance CE 105 (sometimes also referred to as Cx in the art) which is in effect a coupling capacitor. The presence of the body 20 has an effect of introducing shunting capacitances 30 , 32 , 33 which are then grounded via the body 20 by an equivalent grounding capacitor 22 to the ground 34 . Thus the presence of the body 20 affects the amount of charge transferred from the Y plate of the key and therefore provides a way of detecting the presence of the body 20 . This is because the capacitive coupling between the X plate 100 and the Y plate 104 of the key CE 105 reduces as a result of the T-bridge effect caused by the increased capacitance 33 .
[0043] It will be appreciated by the skilled person that FIGS. 1 a and 1 b are depicting a so-called active capacitive sensors based on measuring the capacitive coupling between two electrodes (rather than between a single sensing electrode and a system ground). The principles underlying active capacitive sensing techniques are described in U.S. Pat. No. 6,452,514. In an active-type sensor, one electrode, the so called drive electrode, is supplied with an oscillating drive signal. The degree of capacitive coupling of the drive signal to the sense electrode is determined by measuring the amount of charge transferred to the sense electrode by the oscillating drive signal. The amount of charge transferred, i.e. the strength of the signal seen at the sense electrode, is a measure of the capacitive coupling between the electrodes. When there is no pointing object near to the electrodes, the measured signal on the sense electrode has a background or quiescent value. However, when a pointing object, e.g. a user's finger, approaches the electrodes (or more particularly approaches near to the region separating the electrodes), the pointing object acts as a virtual ground and sinks some of the drive signal (charge) from the drive electrode. This acts to reduce the strength of the component of the drive signal coupled to the sense electrode. Thus a decrease in measured signal on the sense electrode is taken to indicate the presence of a pointing object.
[0044] FIG. 3 provides a circuit diagram, which forms a touch sensor by sensing an amount of charge transferred from the X plate 100 shown in FIG. 2 to the Y plate 104 and includes a charge measurement circuit which has been reproduced from WO-00/44018, which corresponds to U.S. Pat. No. 6,452,514.
[0045] As shown a drive circuit 101 is connected to the X plate 100 of the key 105 and the Y plate 104 of the key 105 is connected to an input 106 of a charge measurement circuit 108 , wherein the X and Y plates collectively form the capacitor 105 . The input 106 is connected to a first controllable switch 110 and to one side of a measuring capacitor Cs 112 on which charge is accumulated as a measure of capacitive coupling. The other side of the measurement capacitor 112 is connected via a second controllable switch 114 to an output 116 of the measurement circuit 108 which is fed as a voltage VOUT to a controller 118 . A first input control channel 103 is used to control the operation of the drive circuit 101 . The first and second controllable switches 110 and 114 are controlled by the controller 118 through respective first and second switch control lines 146 and 148 Similarly, the drive circuit 101 is controlled by the controller 118 through the first input control channel 103 .
[0046] In the illustrated circuit diagram, a convention has been adopted whereby a control input of each of the switches 110 , 114 is open when the control input is “0” and closed when the control input is “1”. The other side of each of the switches 110 , 114 is connected to ground, so that if the control input is “1” then the connecting input would be connected to ground. A similar convention has been adopted for drive circuit 101 , whereby when the control input 103 is “0” the X plate is connected to ground and when the control input is “1” the X plate is connected to a reference voltage “V”.
[0047] FIG. 4 is a timing diagram which shows the operation of the touch sensor, and in particular the function of the measurement circuit arranged to measure the amount of charge transferred from the X plate 100 to the Y plate 104 of the key 105 .
[0048] Four timing diagrams 130 , 132 , 134 , 138 are shown to illustrate the operation of the measurement circuit 108 .
[0049] A first timing diagram 130 represents the control input applied to the second switch 114 . On the left hand side, the logical value of the control input is shown, whereas on the right hand side the effect at the connecting point 114 . 1 is shown to be either “Z” in which the connecting point 114 . 1 is isolated or floating, or for a logical control input of 1 grounded.
[0050] A second timing diagram 132 represents the control input applied to the first switch 110 . The logical control input values “0” or “1” of a connecting point 110 . 1 are shown at either floating (Z) or ground (0).
[0051] A third timing diagram 134 shows a relative timing of a drive signal provided to the X plate 100 of the key in which case, in contrast to the timing diagrams 130 , 132 for the two switches 110 , 114 , the value of the timing diagram is an absolute value so that the left hand side illustrates that the voltage varies between ground and the reference voltage “V”, which is the voltage used to charge the X plate 100 .
[0052] A fourth timing diagram 138 provides an illustration of the example signal strength or voltage produced on the measurement capacitor 112 as a result of the opening and closing of the switches 110 , 114 and the driving of the X plate 100 in accordance with the timing illustrated by the timing diagrams 130 , 132 , 134 . The timing diagrams 130 , 132 , 134 , 138 will now be explained as follows:
[0053] At a first time t 1 , the charge measurement circuit 108 is initialised, i.e. reset, using control lines 146 and 148 for respective switches 110 and 114 being high (1) and control line 103 for drive circuit 101 being low (0). Control lines 146 , 148 , 103 are lines connected to the controller 118 . The Y plate 104 , the X plate 100 and the charge measurement capacitor 112 are thus set to ground. Correspondingly, the output voltage across the charge measurement circuit 112 is at zero. It will be appreciated that connections to ground and VDD could be reversed in other embodiments.
[0054] At a second time t 2 the logical input to the second switch 114 is set low (0), thereby opening the switch and floating the connecting point 114 . 1 .
[0055] At a third time t 3 the control input to the switch 110 is set low (0), thereby floating the connecting point 110 . 1 , which is YA before, at a time t 4 the control input 103 of the drive circuit 101 is set high (1), thereby the X plate 100 of the key 105 is connected to the reference voltage “V”. Then, in order to charge the measurement capacitor Cs for a period S between t 5 and t 6 , the control input to the second switch 114 is set high (1), thereby grounding YB to transfer charge induced on the Y plate of the key 105 onto the charge measurement capacitor 112 , until time t 6 , when the control input to the second switch 114 is set low (0), which again floats the connecting point 114 . 1 . After charging the measurement capacitor Cs for a first dwell time between t 5 and t 6 , at t 7 the control input to the first switch 110 is set high (1), thereby grounding the connecting point 110 . 1 , which is connected to the other side of the charge measurement capacitor Cs 112 . As a result, the voltage across the measurement capacitor can be measured. The amount of charge transferred from the Y plate 104 onto the measurement capacitor Cs 112 during the dwell time between t 5 and t 6 is represented as the output voltage VOUT.
[0056] At time t 8 the control input 103 to the drive circuit 101 goes low (0), thereby the X plate 100 of the key 105 is connected to ground which concludes a first measurement cycle.
[0057] At time t 9 the next measurement cycle of a measurement burst occurs. At t 9 the control input to the switch 110 goes low (0) thereby floating YA, before the control input 103 to the drive circuit 101 again goes high (1), thereby connecting the X plate 100 to the reference voltage “V”, at time t 10 . The measurement capacitor 112 is again charged from charge transferred from the Y plate 104 of the key onto the measurement capacitor 112 . As with the first burst at point t 11 the control input to the switch 114 goes high (1) thereby grounding the point 114 . 1 and driving charge onto the measurement capacitor until t 12 , when the control input to the switch 114 goes low, again floating YB. Thus again charge is transferred from the Y plate 104 during the dwell period between t 11 and 02, thereby increasing the voltage across the measurement capacitor Cs as represented as the output voltage VOUT. It will be appreciated that in FIG. 4 , VOUT is shown with respect to a ground connection at YA, i.e. if point 110 . 1 is ground.
[0058] At t 13 the control input to the switch 110 is set high (1) thereby grounding YA and at t 14 control input 103 to the drive circuit 101 goes low (0), thereby connecting the X plate 100 of the key 105 to ground which concludes the second measurement cycle. Thus, as with the first measurement cycle, an amount of charge has been transferred from the Y plate, which has then increased the voltage across the measurement capacitor 112 , which represents an amount of charge transferred from the Y plate.
[0059] After ‘n’ measurement cycles of a burst, ‘n’ packets of charge will have been transferred from the Y plate to the measurement capacitor 112 where the charge is accumulated. By bursting in this way the signal from each transfer is averaged on the measurement capacitor 112 , so that when it is read out noise reduction has effectively already taken place, as is well known in the art.
[0060] The amount of charge on the measurement capacitor 112 is determined with the aid of a resistor 140 . One side of the resistor 140 is connected to the measurement capacitor 112 and the other side, labeled SMP, is connected to a controllable discharge switch 142 . The discharge switch 142 is connected to receive a control signal from the controller 118 via a control channel 144 . The discharge switch 142 floats SMP when in position ‘0’ and connects SMP to a voltage VDD when in position ‘1’. The float position is selected during measurement, i.e. during the cycles illustrated in FIG. 4 , and the VDD position is selected to discharge the measurement capacitor Cs 112 through the discharge resistor 140 after charge accumulation through a number of cycles.
[0061] The controller 118 is operable to determine the amount of charge accumulated on the measurement capacitor by measuring the amount of time, e.g. by counting the number of clock periods, it takes for the charge on the measurement capacitor Cs to discharge, i.e. the amount of time for the voltage VOUT to reduce to zero. The number of clock periods can therefore be used to provide a relative signal sample value for the respective measured charge signal. This is preferably achieved using a comparator that compares VOUT to a zero or ground signal, while capacitor Cs is discharged.
[0062] Using the same principles of construction and operation, a matrix or grid of touch sensitive switches can be formed to provide a 2DCT sensor. A user can then at a given time select one, or in some cases a plurality of, positions on a sensitive area.
[0063] FIG. 5 shows a two-dimensional touch sensor employing an array of sensors of the kind described with respect to FIGS. 3 and 4 . The charge measurement circuit is used in conjunction with drive circuits 101 . 1 , 101 . 2 , 101 . 3 , 101 . 4 and is arranged to drive different sensor points 205 . As shown each of the drive circuits 101 . 1 , 101 . 2 , 101 . 3 , 101 . 4 is controlled by the controller 118 to drive each of the corresponding lines X 1 , X 2 , X 3 , X 4 , using first control inputs 103 . 1 , 103 . 2 , 103 . 3 , 103 . 4 in the same way as the X plate 100 is driven in FIG. 3 and represented in FIG. 4 . Similarly, an input 107 provides a reference voltage “V”.
[0064] The output of the coupling capacitors at each of the points 205 are connected to one side of measuring capacitors Cs 112 . 1 , 112 . 2 , 112 . 3 , 112 . 4 which are arranged to measure an amount of charge present on the Y plate, Y 1 , Y 2 , Y 3 , Y 4 providing output signals 116 . 1 , 116 . 2 , 116 . 3 , 116 . 4 to detect the presence of an object in the same way as the operation of the circuit shown in FIG. 3 and FIG. 4 . This is achieved by applying control signals to the switches 110 a , 110 b , 110 c , 110 d , 114 a , 114 b , 114 c , 114 d in a corresponding manner to the arrangement explained above with reference to FIGS. 3 and 4 .
[0065] In FIG. 5 , some of the detail from FIG. 3 has been omitted for clarity. In particular the resistor 140 , its switch 142 and actuating line 144 are not shown. It is noted that each of the switches 142 can be commonly actuated by a single actuating line 144 from the controller 118 , since they only need to be switched together to perform their function described above.
[0066] More details for the operation of such a matrix circuit are disclosed in WO-00/44018.
[0067] The controller operates as explained above to detect the presence of an object above one of the matrix of keys 205 , from a change in the capacitance of the keys, through a change in an amount of charge induced on the key during a burst of measurement cycles. However, the presence of a noise signal can induce charge onto the keys of a touch sensor and provide a false detection or prevent a detection being made.
[0068] FIG. 6 shows timing diagrams 130 , 132 , 134 , 138 and 600 used to illustrate the further operation of the of the measurement circuit 108 shown in FIG. 3 to reduce the effects of noise according to an embodiment of the invention.
[0069] The tinning diagrams 130 , 132 , 134 and 138 correspond to the same timing diagrams shown on FIG. 4 , except that the timing diagrams shown in FIG. 6 precede those shown in FIG. 4 , i.e. they run from t- 10 to t 1 . The same convention for each of the switches 110 and 114 shown in FIGS. 3 and 4 is adopted here. The convention for the switch 142 , corresponding to the timing diagram 600 , is also shown in FIG. 3 . The control signal 144 connects the SMP resistor 140 to either float (Z) or VDD depending on its position which is determined by the control line 144 . When the control line 144 is high (1) switch 142 connects SMP resistor 140 to the VDD. When the control line is low (0) switch 142 connects resistor 140 to float (Z).
[0070] The timing diagrams 130 , 132 , 134 and 138 for YB, YA, X and VOUT respectively correspond to those shown in FIG. 4 and described above. Timing diagram 600 represents the control input applied to the switch 142 . On the left hand side, the logical value of the control input is shown, whereas on the right hand side the effect at the SMP resistor 140 is shown to be either “VDD” in which the resistor 142 is connected to VDD or float (Z) in which the resistor 142 is floated. The timing diagrams 130 , 132 , 134 , 138 and 600 will now be described.
[0071] In FIG. 6 at a first time t- 10 , the charge measurement circuit 108 is initialized with both the control inputs for the switches 110 , 114 being high (1) so that both the Y plate and the charge measurement capacitor 112 are set to ground and the input to the switch 142 is set low (0) so that the resistor 140 is floated. This is to discharge the capacitor.
[0072] At time t- 9 , the logical input to the control switch 114 is set to zero, thereby opening the switch and floating the connecting point 114 . 1 which connects the output voltage 116 to one side of the measurement capacitor Cs 112 .
[0073] At a next time t- 8 the control input to the switch 142 is set to high (1), thereby connecting the resistor 140 to VDD. The measurement capacitor Cs 112 is now connected to ground at one side and to VDD via the SMP resistor 140 on the other side, thereby charging the capacitor. The measurement capacitor Cs 112 is charged for a predetermined time T to charge Cs by a set amount. This direct charging of the measurement capacitor Cs bypassing the X drive circuit 101 is referred to as a pre-charging. The pre-charge on the capacitor can be calculated, since the voltage, the value of the capacitor Cs 112 , the value of the resistor 140 and the charge time T are all known. VOUT 138 shows the voltage of the capacitor between t- 8 and t- 7 .
[0074] At time t- 7 the control input to the switch 142 is set low (0) thereby floating the SMP resistor 140 . At time t- 6 the control input to switch 110 is set low (0) thereby point 110 . 1 is floating.
[0075] To measure the amount of noise on the coupling capacitor, switches 110 , 114 and 142 are driven in the same way as if they were collecting signal measurements, i.e. the same way as described with reference to FIG. 4 , with the exception that the X drive circuit 101 is not driven. Namely, as can be seen from FIG. 6 , the control switch to the X plate remains low (0) from time t- 10 to t 1 , so no voltage is applied to the X plate 100 of the coupling capacitor 105 . As a result, the charge accumulated on the measurement capacitor 112 is the pre-charge modulated by packets of charge picked up on the Y plate 104 of the coupling capacitor 105 during the acquisition cycles. This modulation will be a measure of noise, since it can only have been noise that has induced charge on the coupling capacitor 105 , given the absence of X drive signal during the dwell times of each cycle.
[0076] To summarize, a noise measurement is made by mimicking the signal measurement, but without driving the X plate 100 . Moreover, by pre-charging the accumulation capacitor before mimicking a normal signal measurement without driving the X plate, noise is measured through its modulation of the amount of charge initially placed on the charge accumulation capacitor by the pre-charge.
[0077] In order to charge or discharge the measurement capacitor Cs for a period S between t- 5 and t- 4 , the control input to the switch 114 is set high (1) thereby grounding YB to transfer charge induced on the Y plate 104 of the key 105 , due to noise, onto the charge measurement capacitor 112 , until t- 4 when the control input to the switch 114 is set to low (0), which again floats the connecting point 114 . 1 . During time t- 5 to t- 4 noise is accumulated on the capacitor Cs as shown on VOUT 138 . The noise accumulated on the capacitor Cs during the dwell time could result in the voltage at time t- 4 being higher or lower than the voltage at time t- 5 . Two different outcomes are illustrated in FIG. 6 for VOUT 138 at time t- 4 . These are illustrated as solid line 602 , between tunes t- 5 and t- 1 and dotted line 604 between time t- 5 and t- 1 . The solid line 602 illustrates a noise signal that has removed charge from the measurement capacitor Cs and the dotted line 604 illustrates a noise signal that has added charge to the measurement capacitor Cs.
[0078] After charging the measurement capacitor Cs for a first dwell time S between t- 5 and t- 4 , at t- 3 the control input to switch 110 is set high (1), thereby grounding the connecting point 110 . 1 (YA), which is connected to the other side of the charge measurement capacitor Cs 112 . This will allow the charge on the capacitor Cs to be measured.
[0079] The measurement of the charge accumulated on capacitor Cs is carried out in the same manner as described above for measuring the charge accumulated on the capacitor due to a touch. At time t- 2 the control input 144 to switch 142 goes high (1), thereby connecting the SMP resistor to VDD. As a result, the voltage across the measurement capacitor Cs 112 can be measured between times t- 2 and t- 1 . The amount of charge transferred from the Y plate 104 onto the measurement capacitor Cs 112 during the dwell time between t- 5 and t- 4 in addition to the pre-charged charge on the measurement capacitor is measured using the method described above. The read-out time U is used to determine the amount of charge on the capacitor Cs, in addition to the capacitance of the capacitor Cs, which is known.
[0080] It will be appreciated that the read-out time for each of the two outcomes represented by the solid line 602 and the dotted line 604 will be different i.e. the time to discharge the measurement capacitor Cs for the scenario illustrated by the dotted line 604 will be higher than for the scenario represented by the solid line 602 . However, for simplicity these have been shown having the same read-out time in FIG. 6 .
[0081] At time t 0 the control switch 114 is set high (1) so that the timing diagram continues on to time t 1 as shown in FIG. 3 . The control input for switch 142 is held low (0) during the measurement of the charge on the Y plate while the X plate is driven, as described above.
[0082] The process above is only described for a single charge measurement circuit. However, it will be appreciated that the process described above could be carried out on each of the Y plates using each of the charge measurement circuits connected to the Y plates as shown in FIG. 5 .
[0083] In the above example, the noise acquisition precedes the signal acquisition. However, the time sequence is arbitrary. In practice, the measurements will be interspersed, with for example one noise sample being taken followed by several signal samples and then another noise sample etc.
[0084] Once the charge on the measurement capacitor Cs due to noise on the Y plate is measured, the amount of noise is determined. The detected noise is the difference between the charge on the measurement capacitor from the pre-charge cycle and the measured charge on the measurement capacitor after the dwell time. It will be appreciated that the charge on the capacitor after the dwell time could be less than or equal to the pre-charge charge, since charge can be removed from the capacitor as a result of the noise as well as being added. In other words the noise is a charge value that is obtained from subtracting the amount of charge on the measurement capacitor Cs 112 after the pre-charge step from the measured charge on the measurement capacitor Cs 112 after the dwell time. “Noise charge” will be used to identify this charge difference.
[0085] A noise factor is now calculated using the calculated noise charge. To calculate the noise factor, the detected noise charge from the current sample and the previous four samples are used. The standard deviation of these 5 samples is calculated. This will be referred to as the noise factor. It will be appreciated that it is computationally intensive to calculate a square root, so in the preferred embodiment the square of the standard deviation is used. It will be appreciated that more or less samples could be used to obtain the noise factor. Furthermore, it will be appreciated that other methods method for averaging the noise charge could be used.
[0086] The method described above has shown how a noise factor can be calculated using the touch sensor and touch matrix shown in FIGS. 3 and 5 . Examples of how the noise factor is used to reduce the effects of noise in such an arrangement shown in FIGS. 3 and 5 are now described.
[0087] In an embodiment of the invention the controller 118 contains a single filter. The filter could be any type of linear or non-linear filter, for example a low pass filter. The noise factor is used to control whether or not the filter is used. If the noise factor is below a specified threshold the filter is not used. However, if the noise factor is above a specified threshold the filter is applied to the measured signals. For example, if the touch matrix was implemented in a mobile phone, the noise factor during normal operation may fall below the specified value, thereby no filtering is used. However, if the mobile phone is connected to a phone charger during operation, for example, the phone charger may introduce noise. Therefore, if the noise factor due to the phone charger exceeds the specified value the filter would be applied to the measured signal. Once the phone battery is charged and the phone is disconnected from the charger the noise factor will again be below the specified value and the filter will not be applied to the measured signal
[0088] The embodiment of the invention provides a method for configuring one or more filters in response to real time noise signals present on the touch matrix. The sensing hardware shown in FIGS. 3 and 5 typically remains unchanged. Therefore this may be implemented as a firmware update. Since, the method described above provides a method for activating or deactivating filters, when there is no noise source or the noise source is low i.e. below a specified value, the time taken to determine the location of a touch on a touch matrix can be increased, since there is no requirement for filtering.
[0089] In another embodiment the controller 118 may contain a low pass filter that can be configured using the acquired noise factor using the method described above. The frequency pass of the filter may be adjusted based on the amount of noise detected. For example, if the expected signal level detected on the touch matrix is ‘S’, the frequency pass of the filter during normal operation could be ‘S’+10. However, if the detected noise signal is very high for example, then the frequency pass of the filter band could be increased to accommodate a signal with a greater amount of noise. Alternatively, the low pass filter could be replaced with a slew rate limiter. The rate at which the input value is allowed to change is adapted in accordance with the noise factor. If the noise factor is high, the slew rate limiter is adapted to allow signals that change more slowly, i.e. the allowed slew rate is low. Alternatively, if the noise factor is low, the slew rate limiter is adapted to allow signals that change more quickly, i.e. the allow slew rate is high.
[0090] It will be appreciated that other types of slew rate limiter could be used other than a linear changing slew filter. For example where two consecutive samples exceed a predetermined value, the rate of change can be capped to a fixed increment or decrement so that the slew rate limiter can settle on the average value more quickly.
[0091] In summary of the above-described embodiments, a capacitive touch sensor is provided for detecting proximity and location of a body, the sensor comprising: one or multiple X lines; a plurality of Y lines each arranged to have a portion thereof adjacent to a portion of each of the X lines to form a plurality of sensing capacitors; a charge measurement capacitor connected to each Y line; one or more drive circuits arranged to drive respective ones of the X lines to enable charge transfer from the sensing capacitors associated with that X line to the respective measurement capacitors connected to the Y lines. The touch sensor is operable under control of a controller to measure a signal value in the usual way from one of the measurement capacitors, the signal value being indicative of the amount of charge transferred from one of the plurality of Y lines when actuating one of the respective X lines. The touch sensor is further operable under control of a controller to measure a noise value from one of the measurement capacitors indicative of the amount of charge transferred from one of the plurality of Y lines without first actuating one of the respective X lines. Charge is preferably injected onto the charge measurement capacitor before measuring the noise value, so that any noise contribution is accurately measured. | In particular embodiments, an apparatus includes a charge-measurement capacitor having a first plate coupled to a second plate of a coupling capacitor and a non-transitory computer-readable storage medium embodying logic that is operable when executed to ground a first plate of the coupling capacitor; inject a pre-determined amount of charge onto the charge-measurement capacitor; and transfer an amount of charge accumulated on the second plate of the coupling capacitor to the first plate of the charge-measurement capacitor. The charge accumulated on the second plate of the coupling capacitor is due at least in part to noise. The logic is also operable when executed to determine, through a measured voltage across the charge-measurement capacitor, the amount of charge. | Summarize the document in concise, focusing on the main idea's functionality and advantages. | [
"PRIORITY [0001] This application is a continuation under 35 U.S.C. §120 of U.S. patent application Ser.",
"No. 13/290,931 filed on 7 Nov. 2011, which is a continuation under 35 U.S.C. §120 of U.S. patent application Ser.",
"No. 12/255,998 filed on 22 Oct. 2008, now U.S. Pat. No. 8,054,090, each of which is incorporated herein by reference.",
"BACKGROUND OF THE INVENTION [0002] The present invention relates to noise handling in a capacitive touch sensor for detecting proximity of a body, more especially to a capacitive sensor of the so-called active type which is based on measuring the capacitive coupling between a drive and a sense electrode.",
"[0003] There are various forms of touch sensitive controls which use a capacitive sensor to sense the presence of a body such as a user's finger.",
"A form of touch sensitive control is disclosed in WO-00/44018.",
"In this example a pair of electrodes are provided which act as a key so that the presence of a body such as a user's finger is detected as a result of a change in an amount of charge which is transferred between the two electrodes.",
"With this arrangement, one of the electrodes (labeled X) is driven with a drive circuit and the other of the pair of electrodes (labeled Y) is connected to a charge measurement circuit which detects an amount of charge present on the Y plate when driven by the X plate.",
"As disclosed in WO-00/44018 several pairs of electrodes can be arranged to form a matrix of sensing areas which can provide an efficient implementation of a touch sensitive two-dimensional position sensor.",
"Such two dimensional capacitive transducing (2DCT) sensors are typically used with devices which include touch sensitive screens or touch sensitive keyboards/keypads which are used in for example in consumer electronic devices and domestic appliances.",
"[0004] Devices employing 2DCT sensors have become increasingly popular and common not only in conjunction with personal computers but also in all manner of other appliances such as personal digital assistants (PDAs), point of sale (POS) terminals, electronic information and ticketing kiosks, kitchen appliances and the like.",
"2DCT sensors are frequently preferred to mechanical switches for a number of reasons.",
"For example, 2DCT sensors require no moving parts and so are less prone to wear than their mechanical counterparts.",
"2DCT sensors can also be made in relatively small sizes so that correspondingly small, and tightly packed keypad arrays can be provided.",
"Furthermore, 2DCT sensors can be provided beneath an environmentally sealed outer surface/cover panel.",
"This makes their use in wet environments or where there is a danger of dirt or fluids entering a device being controlled attractive.",
"In addition, manufactures often prefer to employ interfaces based on 2DCT sensors in their products because such interfaces are often considered by consumers to be more aesthetically pleasing than conventional mechanical input mechanisms (e.g. push-buttons).",
"[0005] Other devices which may incorporate 2DCT sensors include pen-input tablets and encoders used in machinery for feedback control purposes, for example 2DCT sensors are capable of reporting at least a 2-dimensional coordinate, Cartesian or otherwise, related to the location of an object or human body part by means of a capacitance sensing mechanism.",
"[0006] Although touch sensitive capacitive sensors such as those described above and disclosed in the above-mentioned disclosures have been successfully deployed in many applications, some applications can present a challenging environment for detecting a change in charge as a result of the presence of a body.",
"[0007] For example, the use of a touch sensor on a mobile phone can create a technical problem because there is a variety of disturbing noise signals produced by radio frequency radiation by radio frequency signals and by modulators within the mobile phone.",
"Similarly, a liquid crystal display (LCD) has characteristic switching noise as a result of switching and refreshing pixels.",
"Other types of display may have their own forms of characteristic impulsive noise related to pixel scanning and refresh.",
"Sinusoidal noise, such as that produced by mains electricity may also be present, which can affect the amount of charge detected on a key.",
"This may be significant, for example, when a hand held device such as a mobile telephone is being charged through the mains.",
"[0008] FIG. 7 of the accompanying drawings shows an example of sinusoidal noise in the form of a plot of signal strength or amplitude which may be voltage or charge measured with respect to time.",
"Various points 220 are shown to indicate points at which burst measurements are taken for a touch sensor such as those described above.",
"As will be appreciated, as a result of sinusoidal noise represented by a line 222 , an amount of charge transferred from a key by a measurement capacitor of the measurement circuit such as those described above will vary and therefore could in some circumstances cause a false measurement of the presence of a body.",
"[0009] FIG. 8 of the accompanying drawings shows another form of noise, namely rectangular or impulsive noise, i.e. noise having high frequency components, such as that which might be produced by switching the pixels in a LCD display with which the touch panel is integrated.",
"A plot of signal strength with respect to time is shown with sampling points 220 , which might be produced by bursts of measurement cycles in a measurement circuit such as those described above.",
"Noise impulses 222 are also shown.",
"If a measurement cycle coincides with a rising edge of a noise impulse, as may arise from an LCD switching event, then an erroneous measurement can be produced which can again cause a touch sensor to erroneously detect the presence of a body.",
"[0010] FIG. 9 of the accompanying drawings illustrates this situation showing simultaneous sinusoidal and rectangular noise.",
"As will be appreciated, in general, both sinusoidal noise and rectangular noise may be present during a given time period.",
"Moreover, by its nature, the amount of noise as well as its frequency components will often vary over time.",
"[0011] Prior art capacitive sensors adopt a variety of signal processing techniques to filter noise from the acquired signals.",
"For example, boxcar averagers and detection integrators have been used in the past.",
"In principle other types of standard filtering could be used, and may have been used, such as slew rate filters, high frequency pass filters, low frequency pass filters and band pass filters.",
"[0012] It is desirable to tailor the filtering depending on how noisy the signals arc.",
"For example, it may be desirable to switch certain filters on and off depending on the amount and characteristics of noise, or to set parameters of filters having regard to the noise.",
"SUMMARY OF THE INVENTION [0013] The invention provides a method of measuring proximity of a body to a capacitive sensor device comprising a coupling capacitor having a capacitance sensitive to proximity of a body, and a charge accumulation capacitor having first and second plates, the first plate being connected to the coupling capacitor, and the second plate being connected to a voltage output line.",
"[0014] A signal measurement is made conventionally by transferring charge indicative of the capacitance of the coupling capacitor from the coupling capacitor to the charge accumulation capacitor, and by reading the voltage on the voltage output line, thereby to measure proximity of a body.",
"[0015] An additional noise measurement is made, either before or after the signal measurement, by emulating or mimicking the signal measurement, but inhibiting charge from arising on the coupling capacitor as a result of proximity of a body, thereby to transfer charge indicative of noise induced on the coupling capacitor to the charge accumulation capacitor, and by reading the voltage on the voltage output line, thereby to measure noise.",
"[0016] In a preferred embodiment, a method of measuring proximity of a body to a capacitive sensor device is provided, the capacitive sensor device comprising X and Y electrodes forming respective X and Y plates of a coupling capacitor having a capacitance sensitive to proximity of a body, and a charge accumulation capacitor having first and second plates, the first plate being connected to the Y plate of the coupling capacitor, and the second plate being connected to a voltage output line, the method comprising: making a signal measurement by applying one or more cycles of driving the X electrode with an input voltage, thereby to transfer one or more packets of charge indicative of the capacitance of the coupling capacitor from the coupling capacitor to the charge accumulation capacitor, and by reading the voltage on the voltage output line, thereby to measure proximity of a body;",
"and making a noise measurement, either before or after the signal measurement, by emulating or mimicking the signal measurement, but without driving the X electrode, thereby to transfer one or more packets of charge indicative of noise induced on the coupling capacitor to the charge accumulation capacitor, and by reading the voltage on the voltage output line, thereby to measure noise.",
"[0017] A noise measurement can therefore be obtained whenever desired, for example after every ‘n’ signal measurements, wherein the noise measurement is taken directly from the coupling capacitors that form the sensing nodes of the capacitive sensor device.",
"The noise measurements should therefore be representative of noise levels when the signal measurements are made, since they are obtained using the same circuit elements and interconnects.",
"Moreover, the noise measurements can be made without any additional hardware requirement on the sensor device.",
"[0018] The second plate of the charge accumulation capacitor is preferably connected to a pre-charge line operable to inject a predetermined amount of charge onto the second plate When making the noise measurement, the second plate of the charge accumulation capacitor is then charged before mimicking the signal measurement, thereby to measure noise through its modulation of the amount of charge initially placed on the charge accumulation capacitor.",
"The pre-charge makes the amount of charge accumulated on the charge accumulation capacitor independent of the sign of the charge induced on the Y plate of the coupling capacitor at each cycle of the noise measurement process.",
"This is useful if the controller is not capable of measuring arbitrary voltages from the charge accumulation capacitor.",
"For example, if the controller does not use an analog to digital converter to read off the voltage, but rather a comparator only capable of detecting zero crossings, then the second plate of the charge accumulation capacitor can be pre-charged, e.g. to a certain negative or positive voltage, to ensure that noise contributions will not cause the voltage to change sign before read out, but rather only modulate the pre-charge voltage without changing its sign.",
"[0019] In the noise measurement, charge may be transferred to the charge accumulation capacitor in a plurality of cycles, and the voltage on the voltage output line is read after a predetermined number of said cycles.",
"In order that the noise is not averaged out on the charge accumulation capacitor, the number of cycles is preferably 1, or a small integer number such as 2, 3, 4 or 5.",
"[0020] In the signal measurement, charge may be transferred to the charge accumulation capacitor in a plurality of cycles, and the voltage on the voltage output line is read after a predetermined number of said cycles.",
"Alternatively, charge may be transferred to the charge accumulation capacitor in a plurality of cycles, wherein the cycles are repeated until the voltage on the voltage output line reaches a threshold value, the number of cycles required to reach the threshold value being read as the measure of the capacitance.",
"In the signal measurement, the number of predetermined cycles could be 1, but is preferably a higher number so that the charge accumulation capacitor has an averaging effect on any noise.",
"For example, the number of cycles is preferably at least 5, 10, 20, 30, 40, 50 or 100.",
"The number of cycles over which charge is transferred from the coupling capacitor to the charge accumulation capacitor is often referred to in the art as the burst length.",
"[0021] It will thus be appreciated that the noise measurement will typically use short fixed burst lengths, e.g. of only cycle or a few cycles, whereas the signal measurement will typically use longer burst lengths, which may be fixed, i.e. predetermined in number, or variable, i.e. the number required for the signal to reach a threshold value.",
"Consequently the burst length for the noise measurement will typically be shorter than the burst length for the signal measurement.",
"[0022] The method is applied by interspersing signal measurements and noise measurements.",
"Typically, a plurality of signal measurements are made for each noise measurement.",
"The noise measurements may be limited so that they only occupy a certain minority of the total measurement time, for example a noise measurement may be made after ‘n’ signal measurements, where n might be at least 2, 3, 4, 5, 10, 20, 50 or 100.",
"In a 2DCT, a noise measurement might be made once per frame or once every ‘n’ frames, where collection of a frame of touch data is defined as reading a signal measurement from each of the sensing nodes, i.e. each of the coupling capacitors, of the two-dimensional touch panel.",
"[0023] The invention also provides a capacitive sensor device comprising a coupling capacitor having a capacitance sensitive to proximity of a body, and a charge accumulation capacitor having first and second plates, the first plate being connected to the coupling capacitor, and the second plate being connected to a voltage output line, the device being operable in a first mode to make a signal measurement by transferring charge indicative of the capacitance of the coupling capacitor from the coupling capacitor to the charge accumulation capacitor, wherein the voltage on the voltage output line is a measure of proximity of a body;",
"and the device being operable in a second mode to make a noise measurement by mimicking the signal measurement, but without enabling charge to arise on the coupling capacitor through proximity of a body, thereby to transfer charge indicative of noise induced on the coupling capacitor to the charge accumulation capacitor, wherein the voltage on the voltage output line is a measure of noise.",
"[0024] In a preferred embodiment the invention further provides a capacitive sensor device comprising X and Y electrodes forming respective X and Y plates of a coupling capacitor having a capacitance sensitive to proximity of a body, and a charge accumulation capacitor having first and second plates, the first plate being connected to the Y plate of the coupling capacitor, and the second plate being connected to a voltage output line, the device being operable in a first mode to make a signal measurement by applying successive cycles of driving the X electrode with an input voltage, thereby to transfer successive packets of charge indicative of the capacitance of the coupling capacitor from the coupling capacitor to the charge accumulation capacitor, wherein the voltage on the voltage output line is a measure of proximity of a body;",
"and the device being operable in a second mode to make a noise measurement by mimicking the signal measurement, but without driving the X electrode, thereby to transfer successive packets of charge indicative of noise induced on the coupling capacitor to the charge accumulation capacitor, wherein the voltage on the voltage output line is a measure of noise.",
"[0025] The second plate of the charge accumulation capacitor is preferably connected to a pre-charge line operable to inject a predetermined amount of charge onto the second plate, and wherein, in the noise measurement mode, the second plate of the charge accumulation capacitor is pre-charged before mimicking the signal measurement, thereby to measure noise through its modulation of the amount of charge initially placed on the charge accumulation capacitor by the pre-charge.",
"[0026] The invention provides benefit to single element touch sensor devices, i.e. devices with one or more isolated buttons, as well as to one-dimensional sensors, such as sliders or scroll wheels, and also to two-dimensional sensors, such as alphanumeric key pad emulators and overlays for displays which thereby provide touch screens.",
"[0027] In some embodiments, the device has a plurality of Y electrodes common to each X electrode.",
"In addition, each Y electrode may have its own charge accumulator capacitor.",
"Alternatively, these could be shared through a multiplexer.",
"In a two-dimensional sensor there may be a plurality of X electrodes, and the X and Y electrodes may be arranged to form a two-dimensional array of coupling capacitors distributed over a touch sensitive panel.",
"[0028] The device may further comprise a data acquisition unit, such as a microcontroller or other processor, connected to the voltage output line and operable to measure the voltage on the voltage output line to acquire the signal and noise measurements.",
"The device may still further comprise a filter operable to perform numerical processing on the signal measurements, wherein the filter is operable having regard to the noise measurements.",
"The filter may be hosted by the data acquisition unit and provide signal processing in advance of the signal measurements being supplied to higher level systems components.",
"Alternatively, the filter may be hosted in a higher level system component, such as a central processing unit or digital signal processor.",
"The filter preferably has configuration settings that are modified depending on the noise measurements, e.g. a bandpass filter may have its bandpass range changed, a slew filter may have its increment/decrement coefficients changed.",
"Moreover, the noise measurement may govern whether the filter is applied, for example if noise levels are measured to be low, then the filter may be deactivated.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0029] For a better understanding of the invention, and to show how the same may be carried into effect, reference is now made by way of example to the accompanying drawings, in which: [0030] FIG. 1 a is a schematic block diagram of a touch sensing node, and FIG. 1 b is an example illustration of a user's finger disposed proximate the sensor of FIG. 1 a;",
"[0031] FIG. 2 is a schematic block diagram illustrating an electrical equivalent of the touch sensor shown in FIG. 1 b;",
"[0032] FIG. 3 is a schematic block diagram of a touch sensing circuit for use with the touch sensing node of FIG. 1 a and FIG. 1 b;",
"[0033] FIG. 4 is an example timing diagram illustrating the operation of the sensing circuit shown in FIG. 3 ;",
"[0034] FIG. 5 is a circuit diagram illustrating a touch sensitive matrix providing a two-dimensional capacitive transducing sensor arrangement according to an embodiment of the invention;",
"[0035] FIG. 6 is a tinning diagram illustrating the operation of the sensing circuit shown in FIG. 3 according an embodiment of the invention;",
"[0036] FIG. 7 is a plot of signal strength with respect to time representing a voltage or charge present on a sensing key which has been affected by sinusoidal noise, such as mains noise;",
"[0037] FIG. 8 is a plot of signal strength with respect to time representing the voltage or charge on a sensing key in the presence of rectangular noise, such as LCD noise;",
"and [0038] FIG. 9 is a plot of signal strength with respect to time representing the voltage or charge on a sensing key in the presence of sinusoidal and rectangular noise.",
"DETAILED DESCRIPTION OF THE INVENTION [0039] FIG. 1 a is a schematic cross-section through a touch sensitive control panel 15 in the absence of an actuating body, typically a user's finger or stylus.",
"[0040] FIG. 1 b corresponds to FIG. 1 a , but shows the same cross-section in the presence of an actuating body in the form of a user's finger.",
"[0041] The touch sensor shown in FIGS. 1 a and 1 b corresponds to an example in which a pair of transverse electrodes form a touch sensor.",
"As shown in FIG. 1 a a pair of electrodes 100 , 104 which form a drive or X plate and a receiving or Y plate in the following description are disposed beneath the surface of a touch sensitive control panel 15 .",
"The electrodes 100 , 104 are disposed beneath a dielectric layer 16 , for example a glass or plastics panel.",
"As shown in FIGS. 1 a and 1 b the touch sensor 10 is arranged to detect the presence of a body such as a user's finger 20 as a result of a change in an amount of charge transferred from the Y plate 104 .",
"As shown in FIG. 1 a when the X plate 100 is charged or driven by a circuit, an electric field is formed which is illustrated by the lines 18 and 19 both above and below the touch panel surface 15 as a result of which charge is transferred to the Y plate 104 .",
"The X plate and the Y plate 100 , 104 form a capacitively chargeable sensing node 10 , referred to as a key in the following.",
"As shown in FIG. 1 b as a result of the disturbance of the electric field 18 due to the presence of the user's finger 20 the electric field above the surface of the control panel 15 is disturbed as a result of an earthing or grounding effect provided by the user's finger 20 as illustrated schematically by ground 34 .",
"[0042] An equivalent circuit diagram of the touch sensor shown in FIGS. 1 a and 1 b is shown in FIG. 2 .",
"In FIG. 2 equivalent capacitances are illustrated in the form of a circuit diagram.",
"A capacitance limited between the X plate 100 and the Y plate 104 of the key is a capacitance CE 105 (sometimes also referred to as Cx in the art) which is in effect a coupling capacitor.",
"The presence of the body 20 has an effect of introducing shunting capacitances 30 , 32 , 33 which are then grounded via the body 20 by an equivalent grounding capacitor 22 to the ground 34 .",
"Thus the presence of the body 20 affects the amount of charge transferred from the Y plate of the key and therefore provides a way of detecting the presence of the body 20 .",
"This is because the capacitive coupling between the X plate 100 and the Y plate 104 of the key CE 105 reduces as a result of the T-bridge effect caused by the increased capacitance 33 .",
"[0043] It will be appreciated by the skilled person that FIGS. 1 a and 1 b are depicting a so-called active capacitive sensors based on measuring the capacitive coupling between two electrodes (rather than between a single sensing electrode and a system ground).",
"The principles underlying active capacitive sensing techniques are described in U.S. Pat. No. 6,452,514.",
"In an active-type sensor, one electrode, the so called drive electrode, is supplied with an oscillating drive signal.",
"The degree of capacitive coupling of the drive signal to the sense electrode is determined by measuring the amount of charge transferred to the sense electrode by the oscillating drive signal.",
"The amount of charge transferred, i.e. the strength of the signal seen at the sense electrode, is a measure of the capacitive coupling between the electrodes.",
"When there is no pointing object near to the electrodes, the measured signal on the sense electrode has a background or quiescent value.",
"However, when a pointing object, e.g. a user's finger, approaches the electrodes (or more particularly approaches near to the region separating the electrodes), the pointing object acts as a virtual ground and sinks some of the drive signal (charge) from the drive electrode.",
"This acts to reduce the strength of the component of the drive signal coupled to the sense electrode.",
"Thus a decrease in measured signal on the sense electrode is taken to indicate the presence of a pointing object.",
"[0044] FIG. 3 provides a circuit diagram, which forms a touch sensor by sensing an amount of charge transferred from the X plate 100 shown in FIG. 2 to the Y plate 104 and includes a charge measurement circuit which has been reproduced from WO-00/44018, which corresponds to U.S. Pat. No. 6,452,514.",
"[0045] As shown a drive circuit 101 is connected to the X plate 100 of the key 105 and the Y plate 104 of the key 105 is connected to an input 106 of a charge measurement circuit 108 , wherein the X and Y plates collectively form the capacitor 105 .",
"The input 106 is connected to a first controllable switch 110 and to one side of a measuring capacitor Cs 112 on which charge is accumulated as a measure of capacitive coupling.",
"The other side of the measurement capacitor 112 is connected via a second controllable switch 114 to an output 116 of the measurement circuit 108 which is fed as a voltage VOUT to a controller 118 .",
"A first input control channel 103 is used to control the operation of the drive circuit 101 .",
"The first and second controllable switches 110 and 114 are controlled by the controller 118 through respective first and second switch control lines 146 and 148 Similarly, the drive circuit 101 is controlled by the controller 118 through the first input control channel 103 .",
"[0046] In the illustrated circuit diagram, a convention has been adopted whereby a control input of each of the switches 110 , 114 is open when the control input is “0”",
"and closed when the control input is “1.”",
"The other side of each of the switches 110 , 114 is connected to ground, so that if the control input is “1”",
"then the connecting input would be connected to ground.",
"A similar convention has been adopted for drive circuit 101 , whereby when the control input 103 is “0”",
"the X plate is connected to ground and when the control input is “1”",
"the X plate is connected to a reference voltage “V.”",
"[0047] FIG. 4 is a timing diagram which shows the operation of the touch sensor, and in particular the function of the measurement circuit arranged to measure the amount of charge transferred from the X plate 100 to the Y plate 104 of the key 105 .",
"[0048] Four timing diagrams 130 , 132 , 134 , 138 are shown to illustrate the operation of the measurement circuit 108 .",
"[0049] A first timing diagram 130 represents the control input applied to the second switch 114 .",
"On the left hand side, the logical value of the control input is shown, whereas on the right hand side the effect at the connecting point 114 .",
"1 is shown to be either “Z”",
"in which the connecting point 114 .",
"1 is isolated or floating, or for a logical control input of 1 grounded.",
"[0050] A second timing diagram 132 represents the control input applied to the first switch 110 .",
"The logical control input values “0”",
"or “1”",
"of a connecting point 110 .",
"1 are shown at either floating (Z) or ground (0).",
"[0051] A third timing diagram 134 shows a relative timing of a drive signal provided to the X plate 100 of the key in which case, in contrast to the timing diagrams 130 , 132 for the two switches 110 , 114 , the value of the timing diagram is an absolute value so that the left hand side illustrates that the voltage varies between ground and the reference voltage “V”, which is the voltage used to charge the X plate 100 .",
"[0052] A fourth timing diagram 138 provides an illustration of the example signal strength or voltage produced on the measurement capacitor 112 as a result of the opening and closing of the switches 110 , 114 and the driving of the X plate 100 in accordance with the timing illustrated by the timing diagrams 130 , 132 , 134 .",
"The timing diagrams 130 , 132 , 134 , 138 will now be explained as follows: [0053] At a first time t 1 , the charge measurement circuit 108 is initialised, i.e. reset, using control lines 146 and 148 for respective switches 110 and 114 being high (1) and control line 103 for drive circuit 101 being low (0).",
"Control lines 146 , 148 , 103 are lines connected to the controller 118 .",
"The Y plate 104 , the X plate 100 and the charge measurement capacitor 112 are thus set to ground.",
"Correspondingly, the output voltage across the charge measurement circuit 112 is at zero.",
"It will be appreciated that connections to ground and VDD could be reversed in other embodiments.",
"[0054] At a second time t 2 the logical input to the second switch 114 is set low (0), thereby opening the switch and floating the connecting point 114 .",
"1 .",
"[0055] At a third time t 3 the control input to the switch 110 is set low (0), thereby floating the connecting point 110 .",
"1 , which is YA before, at a time t 4 the control input 103 of the drive circuit 101 is set high (1), thereby the X plate 100 of the key 105 is connected to the reference voltage “V.”",
"Then, in order to charge the measurement capacitor Cs for a period S between t 5 and t 6 , the control input to the second switch 114 is set high (1), thereby grounding YB to transfer charge induced on the Y plate of the key 105 onto the charge measurement capacitor 112 , until time t 6 , when the control input to the second switch 114 is set low (0), which again floats the connecting point 114 .",
"1 .",
"After charging the measurement capacitor Cs for a first dwell time between t 5 and t 6 , at t 7 the control input to the first switch 110 is set high (1), thereby grounding the connecting point 110 .",
"1 , which is connected to the other side of the charge measurement capacitor Cs 112 .",
"As a result, the voltage across the measurement capacitor can be measured.",
"The amount of charge transferred from the Y plate 104 onto the measurement capacitor Cs 112 during the dwell time between t 5 and t 6 is represented as the output voltage VOUT.",
"[0056] At time t 8 the control input 103 to the drive circuit 101 goes low (0), thereby the X plate 100 of the key 105 is connected to ground which concludes a first measurement cycle.",
"[0057] At time t 9 the next measurement cycle of a measurement burst occurs.",
"At t 9 the control input to the switch 110 goes low (0) thereby floating YA, before the control input 103 to the drive circuit 101 again goes high (1), thereby connecting the X plate 100 to the reference voltage “V”, at time t 10 .",
"The measurement capacitor 112 is again charged from charge transferred from the Y plate 104 of the key onto the measurement capacitor 112 .",
"As with the first burst at point t 11 the control input to the switch 114 goes high (1) thereby grounding the point 114 .",
"1 and driving charge onto the measurement capacitor until t 12 , when the control input to the switch 114 goes low, again floating YB.",
"Thus again charge is transferred from the Y plate 104 during the dwell period between t 11 and 02, thereby increasing the voltage across the measurement capacitor Cs as represented as the output voltage VOUT.",
"It will be appreciated that in FIG. 4 , VOUT is shown with respect to a ground connection at YA, i.e. if point 110 .",
"1 is ground.",
"[0058] At t 13 the control input to the switch 110 is set high (1) thereby grounding YA and at t 14 control input 103 to the drive circuit 101 goes low (0), thereby connecting the X plate 100 of the key 105 to ground which concludes the second measurement cycle.",
"Thus, as with the first measurement cycle, an amount of charge has been transferred from the Y plate, which has then increased the voltage across the measurement capacitor 112 , which represents an amount of charge transferred from the Y plate.",
"[0059] After ‘n’ measurement cycles of a burst, ‘n’ packets of charge will have been transferred from the Y plate to the measurement capacitor 112 where the charge is accumulated.",
"By bursting in this way the signal from each transfer is averaged on the measurement capacitor 112 , so that when it is read out noise reduction has effectively already taken place, as is well known in the art.",
"[0060] The amount of charge on the measurement capacitor 112 is determined with the aid of a resistor 140 .",
"One side of the resistor 140 is connected to the measurement capacitor 112 and the other side, labeled SMP, is connected to a controllable discharge switch 142 .",
"The discharge switch 142 is connected to receive a control signal from the controller 118 via a control channel 144 .",
"The discharge switch 142 floats SMP when in position ‘0’ and connects SMP to a voltage VDD when in position ‘1’.",
"The float position is selected during measurement, i.e. during the cycles illustrated in FIG. 4 , and the VDD position is selected to discharge the measurement capacitor Cs 112 through the discharge resistor 140 after charge accumulation through a number of cycles.",
"[0061] The controller 118 is operable to determine the amount of charge accumulated on the measurement capacitor by measuring the amount of time, e.g. by counting the number of clock periods, it takes for the charge on the measurement capacitor Cs to discharge, i.e. the amount of time for the voltage VOUT to reduce to zero.",
"The number of clock periods can therefore be used to provide a relative signal sample value for the respective measured charge signal.",
"This is preferably achieved using a comparator that compares VOUT to a zero or ground signal, while capacitor Cs is discharged.",
"[0062] Using the same principles of construction and operation, a matrix or grid of touch sensitive switches can be formed to provide a 2DCT sensor.",
"A user can then at a given time select one, or in some cases a plurality of, positions on a sensitive area.",
"[0063] FIG. 5 shows a two-dimensional touch sensor employing an array of sensors of the kind described with respect to FIGS. 3 and 4 .",
"The charge measurement circuit is used in conjunction with drive circuits 101 .",
"1 , 101 .",
"2 , 101 .",
"3 , 101 .",
"4 and is arranged to drive different sensor points 205 .",
"As shown each of the drive circuits 101 .",
"1 , 101 .",
"2 , 101 .",
"3 , 101 .",
"4 is controlled by the controller 118 to drive each of the corresponding lines X 1 , X 2 , X 3 , X 4 , using first control inputs 103 .",
"1 , 103 .",
"2 , 103 .",
"3 , 103 .",
"4 in the same way as the X plate 100 is driven in FIG. 3 and represented in FIG. 4 .",
"Similarly, an input 107 provides a reference voltage “V.”",
"[0064] The output of the coupling capacitors at each of the points 205 are connected to one side of measuring capacitors Cs 112 .",
"1 , 112 .",
"2 , 112 .",
"3 , 112 .",
"4 which are arranged to measure an amount of charge present on the Y plate, Y 1 , Y 2 , Y 3 , Y 4 providing output signals 116 .",
"1 , 116 .",
"2 , 116 .",
"3 , 116 .",
"4 to detect the presence of an object in the same way as the operation of the circuit shown in FIG. 3 and FIG. 4 .",
"This is achieved by applying control signals to the switches 110 a , 110 b , 110 c , 110 d , 114 a , 114 b , 114 c , 114 d in a corresponding manner to the arrangement explained above with reference to FIGS. 3 and 4 .",
"[0065] In FIG. 5 , some of the detail from FIG. 3 has been omitted for clarity.",
"In particular the resistor 140 , its switch 142 and actuating line 144 are not shown.",
"It is noted that each of the switches 142 can be commonly actuated by a single actuating line 144 from the controller 118 , since they only need to be switched together to perform their function described above.",
"[0066] More details for the operation of such a matrix circuit are disclosed in WO-00/44018.",
"[0067] The controller operates as explained above to detect the presence of an object above one of the matrix of keys 205 , from a change in the capacitance of the keys, through a change in an amount of charge induced on the key during a burst of measurement cycles.",
"However, the presence of a noise signal can induce charge onto the keys of a touch sensor and provide a false detection or prevent a detection being made.",
"[0068] FIG. 6 shows timing diagrams 130 , 132 , 134 , 138 and 600 used to illustrate the further operation of the of the measurement circuit 108 shown in FIG. 3 to reduce the effects of noise according to an embodiment of the invention.",
"[0069] The tinning diagrams 130 , 132 , 134 and 138 correspond to the same timing diagrams shown on FIG. 4 , except that the timing diagrams shown in FIG. 6 precede those shown in FIG. 4 , i.e. they run from t- 10 to t 1 .",
"The same convention for each of the switches 110 and 114 shown in FIGS. 3 and 4 is adopted here.",
"The convention for the switch 142 , corresponding to the timing diagram 600 , is also shown in FIG. 3 .",
"The control signal 144 connects the SMP resistor 140 to either float (Z) or VDD depending on its position which is determined by the control line 144 .",
"When the control line 144 is high (1) switch 142 connects SMP resistor 140 to the VDD.",
"When the control line is low (0) switch 142 connects resistor 140 to float (Z).",
"[0070] The timing diagrams 130 , 132 , 134 and 138 for YB, YA, X and VOUT respectively correspond to those shown in FIG. 4 and described above.",
"Timing diagram 600 represents the control input applied to the switch 142 .",
"On the left hand side, the logical value of the control input is shown, whereas on the right hand side the effect at the SMP resistor 140 is shown to be either “VDD”",
"in which the resistor 142 is connected to VDD or float (Z) in which the resistor 142 is floated.",
"The timing diagrams 130 , 132 , 134 , 138 and 600 will now be described.",
"[0071] In FIG. 6 at a first time t- 10 , the charge measurement circuit 108 is initialized with both the control inputs for the switches 110 , 114 being high (1) so that both the Y plate and the charge measurement capacitor 112 are set to ground and the input to the switch 142 is set low (0) so that the resistor 140 is floated.",
"This is to discharge the capacitor.",
"[0072] At time t- 9 , the logical input to the control switch 114 is set to zero, thereby opening the switch and floating the connecting point 114 .",
"1 which connects the output voltage 116 to one side of the measurement capacitor Cs 112 .",
"[0073] At a next time t- 8 the control input to the switch 142 is set to high (1), thereby connecting the resistor 140 to VDD.",
"The measurement capacitor Cs 112 is now connected to ground at one side and to VDD via the SMP resistor 140 on the other side, thereby charging the capacitor.",
"The measurement capacitor Cs 112 is charged for a predetermined time T to charge Cs by a set amount.",
"This direct charging of the measurement capacitor Cs bypassing the X drive circuit 101 is referred to as a pre-charging.",
"The pre-charge on the capacitor can be calculated, since the voltage, the value of the capacitor Cs 112 , the value of the resistor 140 and the charge time T are all known.",
"VOUT 138 shows the voltage of the capacitor between t- 8 and t- 7 .",
"[0074] At time t- 7 the control input to the switch 142 is set low (0) thereby floating the SMP resistor 140 .",
"At time t- 6 the control input to switch 110 is set low (0) thereby point 110 .",
"1 is floating.",
"[0075] To measure the amount of noise on the coupling capacitor, switches 110 , 114 and 142 are driven in the same way as if they were collecting signal measurements, i.e. the same way as described with reference to FIG. 4 , with the exception that the X drive circuit 101 is not driven.",
"Namely, as can be seen from FIG. 6 , the control switch to the X plate remains low (0) from time t- 10 to t 1 , so no voltage is applied to the X plate 100 of the coupling capacitor 105 .",
"As a result, the charge accumulated on the measurement capacitor 112 is the pre-charge modulated by packets of charge picked up on the Y plate 104 of the coupling capacitor 105 during the acquisition cycles.",
"This modulation will be a measure of noise, since it can only have been noise that has induced charge on the coupling capacitor 105 , given the absence of X drive signal during the dwell times of each cycle.",
"[0076] To summarize, a noise measurement is made by mimicking the signal measurement, but without driving the X plate 100 .",
"Moreover, by pre-charging the accumulation capacitor before mimicking a normal signal measurement without driving the X plate, noise is measured through its modulation of the amount of charge initially placed on the charge accumulation capacitor by the pre-charge.",
"[0077] In order to charge or discharge the measurement capacitor Cs for a period S between t- 5 and t- 4 , the control input to the switch 114 is set high (1) thereby grounding YB to transfer charge induced on the Y plate 104 of the key 105 , due to noise, onto the charge measurement capacitor 112 , until t- 4 when the control input to the switch 114 is set to low (0), which again floats the connecting point 114 .",
"1 .",
"During time t- 5 to t- 4 noise is accumulated on the capacitor Cs as shown on VOUT 138 .",
"The noise accumulated on the capacitor Cs during the dwell time could result in the voltage at time t- 4 being higher or lower than the voltage at time t- 5 .",
"Two different outcomes are illustrated in FIG. 6 for VOUT 138 at time t- 4 .",
"These are illustrated as solid line 602 , between tunes t- 5 and t- 1 and dotted line 604 between time t- 5 and t- 1 .",
"The solid line 602 illustrates a noise signal that has removed charge from the measurement capacitor Cs and the dotted line 604 illustrates a noise signal that has added charge to the measurement capacitor Cs.",
"[0078] After charging the measurement capacitor Cs for a first dwell time S between t- 5 and t- 4 , at t- 3 the control input to switch 110 is set high (1), thereby grounding the connecting point 110 .",
"1 (YA), which is connected to the other side of the charge measurement capacitor Cs 112 .",
"This will allow the charge on the capacitor Cs to be measured.",
"[0079] The measurement of the charge accumulated on capacitor Cs is carried out in the same manner as described above for measuring the charge accumulated on the capacitor due to a touch.",
"At time t- 2 the control input 144 to switch 142 goes high (1), thereby connecting the SMP resistor to VDD.",
"As a result, the voltage across the measurement capacitor Cs 112 can be measured between times t- 2 and t- 1 .",
"The amount of charge transferred from the Y plate 104 onto the measurement capacitor Cs 112 during the dwell time between t- 5 and t- 4 in addition to the pre-charged charge on the measurement capacitor is measured using the method described above.",
"The read-out time U is used to determine the amount of charge on the capacitor Cs, in addition to the capacitance of the capacitor Cs, which is known.",
"[0080] It will be appreciated that the read-out time for each of the two outcomes represented by the solid line 602 and the dotted line 604 will be different i.e. the time to discharge the measurement capacitor Cs for the scenario illustrated by the dotted line 604 will be higher than for the scenario represented by the solid line 602 .",
"However, for simplicity these have been shown having the same read-out time in FIG. 6 .",
"[0081] At time t 0 the control switch 114 is set high (1) so that the timing diagram continues on to time t 1 as shown in FIG. 3 .",
"The control input for switch 142 is held low (0) during the measurement of the charge on the Y plate while the X plate is driven, as described above.",
"[0082] The process above is only described for a single charge measurement circuit.",
"However, it will be appreciated that the process described above could be carried out on each of the Y plates using each of the charge measurement circuits connected to the Y plates as shown in FIG. 5 .",
"[0083] In the above example, the noise acquisition precedes the signal acquisition.",
"However, the time sequence is arbitrary.",
"In practice, the measurements will be interspersed, with for example one noise sample being taken followed by several signal samples and then another noise sample etc.",
"[0084] Once the charge on the measurement capacitor Cs due to noise on the Y plate is measured, the amount of noise is determined.",
"The detected noise is the difference between the charge on the measurement capacitor from the pre-charge cycle and the measured charge on the measurement capacitor after the dwell time.",
"It will be appreciated that the charge on the capacitor after the dwell time could be less than or equal to the pre-charge charge, since charge can be removed from the capacitor as a result of the noise as well as being added.",
"In other words the noise is a charge value that is obtained from subtracting the amount of charge on the measurement capacitor Cs 112 after the pre-charge step from the measured charge on the measurement capacitor Cs 112 after the dwell time.",
"“Noise charge”",
"will be used to identify this charge difference.",
"[0085] A noise factor is now calculated using the calculated noise charge.",
"To calculate the noise factor, the detected noise charge from the current sample and the previous four samples are used.",
"The standard deviation of these 5 samples is calculated.",
"This will be referred to as the noise factor.",
"It will be appreciated that it is computationally intensive to calculate a square root, so in the preferred embodiment the square of the standard deviation is used.",
"It will be appreciated that more or less samples could be used to obtain the noise factor.",
"Furthermore, it will be appreciated that other methods method for averaging the noise charge could be used.",
"[0086] The method described above has shown how a noise factor can be calculated using the touch sensor and touch matrix shown in FIGS. 3 and 5 .",
"Examples of how the noise factor is used to reduce the effects of noise in such an arrangement shown in FIGS. 3 and 5 are now described.",
"[0087] In an embodiment of the invention the controller 118 contains a single filter.",
"The filter could be any type of linear or non-linear filter, for example a low pass filter.",
"The noise factor is used to control whether or not the filter is used.",
"If the noise factor is below a specified threshold the filter is not used.",
"However, if the noise factor is above a specified threshold the filter is applied to the measured signals.",
"For example, if the touch matrix was implemented in a mobile phone, the noise factor during normal operation may fall below the specified value, thereby no filtering is used.",
"However, if the mobile phone is connected to a phone charger during operation, for example, the phone charger may introduce noise.",
"Therefore, if the noise factor due to the phone charger exceeds the specified value the filter would be applied to the measured signal.",
"Once the phone battery is charged and the phone is disconnected from the charger the noise factor will again be below the specified value and the filter will not be applied to the measured signal [0088] The embodiment of the invention provides a method for configuring one or more filters in response to real time noise signals present on the touch matrix.",
"The sensing hardware shown in FIGS. 3 and 5 typically remains unchanged.",
"Therefore this may be implemented as a firmware update.",
"Since, the method described above provides a method for activating or deactivating filters, when there is no noise source or the noise source is low i.e. below a specified value, the time taken to determine the location of a touch on a touch matrix can be increased, since there is no requirement for filtering.",
"[0089] In another embodiment the controller 118 may contain a low pass filter that can be configured using the acquired noise factor using the method described above.",
"The frequency pass of the filter may be adjusted based on the amount of noise detected.",
"For example, if the expected signal level detected on the touch matrix is ‘S’, the frequency pass of the filter during normal operation could be ‘S’+10.",
"However, if the detected noise signal is very high for example, then the frequency pass of the filter band could be increased to accommodate a signal with a greater amount of noise.",
"Alternatively, the low pass filter could be replaced with a slew rate limiter.",
"The rate at which the input value is allowed to change is adapted in accordance with the noise factor.",
"If the noise factor is high, the slew rate limiter is adapted to allow signals that change more slowly, i.e. the allowed slew rate is low.",
"Alternatively, if the noise factor is low, the slew rate limiter is adapted to allow signals that change more quickly, i.e. the allow slew rate is high.",
"[0090] It will be appreciated that other types of slew rate limiter could be used other than a linear changing slew filter.",
"For example where two consecutive samples exceed a predetermined value, the rate of change can be capped to a fixed increment or decrement so that the slew rate limiter can settle on the average value more quickly.",
"[0091] In summary of the above-described embodiments, a capacitive touch sensor is provided for detecting proximity and location of a body, the sensor comprising: one or multiple X lines;",
"a plurality of Y lines each arranged to have a portion thereof adjacent to a portion of each of the X lines to form a plurality of sensing capacitors;",
"a charge measurement capacitor connected to each Y line;",
"one or more drive circuits arranged to drive respective ones of the X lines to enable charge transfer from the sensing capacitors associated with that X line to the respective measurement capacitors connected to the Y lines.",
"The touch sensor is operable under control of a controller to measure a signal value in the usual way from one of the measurement capacitors, the signal value being indicative of the amount of charge transferred from one of the plurality of Y lines when actuating one of the respective X lines.",
"The touch sensor is further operable under control of a controller to measure a noise value from one of the measurement capacitors indicative of the amount of charge transferred from one of the plurality of Y lines without first actuating one of the respective X lines.",
"Charge is preferably injected onto the charge measurement capacitor before measuring the noise value, so that any noise contribution is accurately measured."
] |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 10/926,148, filed Aug. 25, 2004 now U.S Pat. No. 7,074,890; which application is a continuation of U.S. application Ser. No. 10/226,428, filed Aug. 23, 2002 (now U.S. Pat. No. 6,979,723); which application claims the benefit of U.S. Provisional Application No. 60/314,831, filed on Aug. 24, 2001; the entire disclosures of which are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to novel processes for preparing derivatives of glycopeptide antibiotics. More specifically, this invention is directed to multi-step processes for preparing phosphonate derivatives of glycopeptide antibiotics having an amino-containing side chain, the first two steps being conducted in a single reaction vessel without isolation of the intermediate reaction products.
2. Background
Glycopeptides (e.g. dalbaheptides) are a well-known class of antibiotics produced by various microorganisms (see Glycopeptide Antibiotics , edited by R. Nagarajan, Marcel Dekker, Inc. New York (1994)). Many synthetic derivatives of such glycopeptides are also known in the art and these derivatives are typically reported to have improved properties relative to the naturally-occurring glycopeptides, including enhanced antibacterial activity. For example, U.S. patent application Ser. No. 09/847,042, filed May 1, 2001, describes various glycopeptide phosphonate derivatives, some of which contain an amino-containing side chain. Such phosphate derivatives are particularly useful as antibiotics for treating gram-positive infections.
Accordingly, a need exists for new efficient processes which are useful for preparing phosphonate derivatives of glycopeptide antibiotics having an amino-containing side chain.
SUMMARY OF THE INVENTION
The present invention provides novel processes for preparing phosphonate derivatives of glycopeptide antibiotics having an amino-containing side chain. Among other advantages, the first two steps of the present process are conducted in a single reaction vessel without isolation of the intermediate reaction products, thereby generating less waste and improving the overall efficiency and yield of the process compared to previous processes.
Specifically, in one of its aspects, this invention is directed to a process for preparing a compound of formula 1:
wherein
R 1 is selected from the group consisting of C 1-10 alkylene, C 2-10 alkenylene and C 2-10 alkynylene;
R 2 is selected from the group consisting of C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, C 3-8 cycloalkyl, C 5-8 cycloalkenyl, C 6-10 aryl, C 2-9 heteroaryl, C 2-9 heterocyclic, —R a -Cy 1 , —R a —Ar 1 —Ar 2 , —R a —Ar 1 —R b —Ar 2 , —R a —Ar 1 —O—R b —Ar 2 ;
R 4 is C 1-10 alkylene;
R a is selected from the group consisting of C 1-10 alkylene, C 1-10 alkenylene and C 1-10 alkynylene;
R b is selected from the group consisting of C 1-6 alkylene, C 1-6 alkenylene and C 1-6 alkynylene;
Cy 1 is selected from the group consisting of C 3-8 cycloalkyl, C 5-8 cycloalkenyl, C 6-10 aryl, C 2-9 heteroaryl, C 2-9 heterocyclic;
Ar 1 and Ar 2 are independently selected from C 6-10 aryl and C 2-9 heteroaryl;
wherein each aryl, heteroaryl and heterocyclic group is optionally substituted with 1 to 3 substituents independently selected from the group consisting of C 1-6 alkyl, C 1-6 alkoxy, halo, hydroxy, nitro and trifluoromethyl, and each heteroaryl and heterocyclic group contains from 1 to 3 heteroatoms selected from nitrogen, oxygen or sulfur;
or a salt thereof;
the process comprising:
(a) reacting vancomycin or a salt thereof, with a compound of formula II:
wherein R 1 and R 2 are as defined herein; and R 3 is a amine-labile protecting group; and a reducing agent to form a compound of formula III:
wherein R 1 , R 2 and R 3 are as defined herein or a salt thereof;
(b) reacting the compound of formula III with an amine to provide a compound of formula IV:
wherein R 1 and R 2 are as defined herein, or a salt thereof; wherein step (a) and step (b) are conducted in the same reaction mixture without isolation of the intermediate from step (a); and
(c) reacting the compound of formula IV with formaldehyde and a compound of formula V:
in the presence of a base to provide a compound of formula I, or a salt thereof.
In the above process, R 1 is preferably C 1-6 alkylene. More preferably, R 1 is C 1-2 alkylene. Still more preferably, R 1 is —CH 2 —.
R 2 is preferably C 6-14 alkyl. More preferably, R 2 is C 8-12 alkyl. Still more preferably, R 2 is n-decyl.
In the process of this invention, R 3 is an amino-protecting group which is removed by treatment with an amine (i.e., a nucleophilic amine). Preferably, R 3 is a group of formula (A):
W—OC(O)— (A)
wherein W is selected from the group consisting of 9-fluorenylmethyl, 3-indenylmethyl, benz[f]inden-3-ylmethyl, 17-tetrabenzo[a,c,g,i]fluorenylmethyl, 2,7-di-tert-butyl[9-(10,10-dioxo-10,10,10,10-tetrahydrothioxanthyl)]methyl, 1,1-dioxobenzo[b]thiophene-2-ylmethyl, wherein the 9-fluorenylmethyl group is optionally substituted with 1 to 3 substitutents selected from the group consisting of C 1-6 alkyl, halo, nitro and sulfo.
Preferably, W is 9-fluorenylmethyl, wherein the 9-fluorenylmethyl group is optionally substituted with 1 to 3 substitutents selected from the group consisting of C 1-6 alkyl, halo, nitro and sulfo. More preferably, W is 9-fluorenylmethyl.
Preferably, R 4 is C 1-6 alkylene. More preferably, R 4 is C 1-4 alkylene. Still more preferably, R 4 is —CH 2 —.
In step (a), the reducing agent is preferably an amine/borane complex. More preferably, the reducing agent is pyridine/borane or tert-butylamine/borane; and still more preferably, the reducing agent is tert-butylamine/borane.
In a preferred embodiment of this process, step (a) comprises the steps of:
(i) combining vancomycin or a salt thereof with a compound of formula II in the presence of base to form a reaction mixture;
(ii) acidifying the reaction mixture from step (i) with an acid; and
(iii) contacting the reaction mixture from step (ii) with a reducing agent.
In this preferred embodiment, the base in step (i) is preferably a tertiary amine; more preferably, the base is diisopropylethylamine.
Preferably, the acid employed in step (ii) is trifluoroacetic acid or acetic acid.
In step (b), the amine employed is preferably ammonium hydroxide or a primary amine. More preferably, the amine is ammonium hydroxide, methylamine or tert-butylamine; and still more preferably, the amine is tert-butylamine.
In step (c), the base employed is preferably a tertiary amine. Preferably, the tertiary amine employed is diisopropylethylamine. In a preferred embodiment, the molar ratio of tertiary amine to compound of formula V is about 3:1 to about 5:1; more preferably, about 4:1.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to novel processes for preparing glycopeptide phosphonate derivatives having an amino-containing side chain. When describing such processes, the following terms have the following meanings, unless otherwise indicated.
DEFINITIONS
The term “alkyl” refers to a monovalent saturated hydrocarbon group which may be linear or branched. Unless otherwise defined, such alkyl groups typically contain from 1 to 20 carbon atoms. Representative alkyl groups include, by way of example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl and the like.
The term “alkenyl” refers to a monovalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon double bonds. Unless otherwise defined, such alkenyl groups typically contain from 2 to 20 carbon atoms. Representative alkenyl groups include, by way of example, ethenyl, n-propenyl, isopropenyl, n-but-2-enyl, n-hex-3-enyl and the like.
The term “alkynyl” refers to a monovalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon triple bonds. Unless otherwise defined, such alkynyl groups typically contain from 2 to 20 carbon atoms. Representative alkynyl groups include, by way of example, ethynyl, n-propynyl, n-but-2-ynyl, n-hex-3-ynyl and the like.
The term “alkylene” refers to a divalent saturated hydrocarbon group which may be linear or branched. Unless otherwise defined, such alkylene groups typically contain from 1 to 10 carbon atoms. Representative alkylene groups include, by way of example, methylene, ethane-1,2-diyl (“ethylene”), propane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl and the like.
The term “alkenylene” refers to a divalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon double bonds. Unless otherwise defined, such alkenylene groups typically contain from 2 to 10 carbon atoms. Representative alkenylene groups include, by way of example, ethene-1,2-diyl, prop-1-ene-1,2-diyl, prop-1-ene-1,3-diyl, but-2-ene-1,4-diyl, and the like.
The term “alkynylene” refers to a divalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon triple bonds. Unless otherwise defined, such alkynylene groups typically contain from 2 to 10 carbon atoms. Representative alkynylene groups include, by way of example, ethyne-1,2-diyl, prop-1-yne-1,2-diyl, prop-1-yne-1,3-diyl, but-2-yne-1,4diyl, and the like.
The term “alkoxy” refers to a group of the formula —O—R, where R is alkyl as defined herein. Representative alkoxy groups include, by way of example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy and the like.
The term “aryl” refers to a monovalent aromatic hydrocarbon having a single ring (i.e., phenyl) or fused rings (i.e., naphthalene). Unless otherwise defined, such aryl groups typically contain from 6 to 10 carbon ring atoms. Representative aryl groups include, by way of example, phenyl and naphthalene-1-yl, naphthalene-2-yl, and the like.
The term “cycloalkyl” refers to a monovalent saturated carbocyclic hydrocarbon group. Unless otherwise defined, such cycloalkyl groups typically contain from 3 to 10 carbon atoms. Representative cycloalkyl groups include, by way of example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like.
The term “cycloalkenyl” refers to a monovalent unsaturated carbocyclic hydrocarbon group having at least one carbon-carbon double bond in the carbocyclic ring. Unless otherwise defined, such cycloalkenyl groups typically contain from 5 to 10 carbon atoms. Representative cycloalkenyl groups include, by way of example, cyclopent-3-en-1-yl, cyclohex-1-en-1-yl and the like.
The term “halo” refers to fluoro, chloro, bromo and iodo; preferably, chloro, bromo and iodo.
The term “heteroaryl” refers to a monovalent aromatic group having a single ring or two fused rings and containing in the ring at least one heteroatom (typically 1 to 3 heteroatoms) selected from nitrogen, oxygen or sulfur. Unless otherwise defined, such heteroaryl groups typically contain from 5 to 10 total ring atoms. Representative heteroaryl groups include, by way of example, monovalent species of pyrrole, imidazole, thiazole, oxazole, fur, thiophene, triazole, pyrazole, isoxazole, isothiazole, pyridine, pyrazine, pyridazine, pyrimidine, triazine, indole, benzofuran, benzothiophene, benzimidazole, benzthiazole, quinoline, isoquinoline, quinazoline, quinoxaline and the like, where the point of attachment is at any available carbon or nitrogen ring atom.
The term “heterocycle” or “heterocyclic” refers to a monovalent saturated or unsaturated (non-aromatic) group having a single ring or multiple condensed rings and containing in the ring at least one heteroatom (typically 1 to 3 heteroatoms) selected from nitrogen, oxygen or sulfur. Unless otherwise defined, such heterocyclic groups typically contain from 2 to 9 total ring atoms. Representative heterocyclic groups include, by way of example, monovalent species of pyrrolidine, imidazolidine, pyrazolidine, piperidine, 1,4-dioxane, morpholine, thiomorpholine, piperazine, 3-pyrroline and the like, where the point of attachment is at any available carbon or nitrogen ring atom.
The term “vancomycin” is used herein in its art recognized manner to refer to the glycopeptide antibiotic known as vancomycin. See, for example, R. Nagarajan, “Glycopeptide Anitibiotics”, Marcel Dekker, Inc. (1994) and references cited therein. The designation “N van -” refers to substitution at the vancosamine nitrogen atom of vancomycin. This position is also referred to as the N3″ position of vancomycin. Additionally, using a conventional vancomycin numbering system, the designation “29-” refers to the carbon atom position between the two hydroxyl groups on the phenyl ring of amino acid 7 (AA-7). This position is also sometimes referred to as the “7d” or the “resorcinol position” of vancomycin.
The term “salt” when used in conjunction with a compound referred to herein refers to a salt of the compound derived from an inorganic or organic base or from an inorganic or organic acid. Salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic, manganous, potassium, sodium, zinc and the like. Particularly preferred are ammonium, calcium, magnesium, potassium and sodium salts. Salts derived from organic bases include salts of primary, secondary and tertiary amines, including substituted amines, cyclic amines, naturally occuring amines and the like, such as arginine, betaine, caffeine, choline, N,N′-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperadine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine and the like. Salts derived from acids include acetic, ascorbic, benzenesulfonic, benzoic, camphosulfonic, citric, ethanesulfonic, fumaric, gluconic, glucoronic, glutamic, hippuric, hydrobromic, hydrochloric, isethionic, lactic, lactobionic, maleic, malic, mandelic, methanesulfonic, mucic, naphthalenesulfonic, nicotinic, nitric, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic and the like. Particularly preferred are citric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric and tartaric acids.
The term “protecting group” or “blocking group” refers to a group which, when covalently attached to a function group such as an amino, hydroxyl, thiol, carboxyl, carbonyl and the like, prevents the functional group from undergoing undesired reactions but which permits the function group to be regenerated (i.e., deprotected or unblocked) upon treatment of the protecting group with a suitable reagent. Representative protecting groups are disclosed, for example, in T. W. Greene and P. G. M. Wuts, “Protective Groups in Organic Synthesis” 3rd Ed., 1999, John Wiley and Sons, N.Y.
The term “amine-labile protecting group” refers to a protecting group which is removed upon treatment with a suitable amine.
Process Conditions
The process of the present invention is conducted in three steps beginning with vancomycin or a salt thereof. The first step of the process is a reductive alkylation step which involves first combining one equivalent of vancomycin or a salt thereof, with one or more equivalents of an aldehyde of formula II:
wherein R 1 , R 2 and R 3 are as defined herein to form a imine and/or hemiaminal intermediate in situ.
The aldehydes of formula II employed in the process of the present invention are well-known in the art and are either commercially available or can be prepared by conventional procedures using commercially available starting materials and conventional reagents. For example, see WO 00/39156, published on Jul. 6, 2000, which describes various methods for preparing such aldehydes.
Typically, the vancomycin or a salt thereof and the aldehyde are combined in an inert diluent in the presence of an excess amount of a suitable base to form a reaction mixture. Preferably, the inert diluent is N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, acetonitrile/water, and the like or mixtures thereof Preferably, from about 1 to about 2 equivalents of the aldehyde are employed; more preferably, about 1.1 to about 1.2 equivalents. In this reaction mixture, a mixture of imines and/or hemiaminals is believed to be formed between the aldehyde and the basic nitrogen atoms of vancomycin, i.e., the vancosamine nitrogen atom and the N-terminal (leucinyl) nitrogen atom.
Formation of the imine and/or hemiaminal intermediate is typically conducted at a temperature ranging from about 0° C. to about 75° C., preferably at ambient temperature (i.e., about 20-25° C.) for about 1 to about 24 hours, preferably for about 6 to 12 hours, or until formation of the imine and/or hemiaminal is substantially complete.
Any suitable base may be employed to neutralize the vancomycin salt and to facilitate formation of the imine and/or hemiaminal, including organic bases, such as amines, alkali metal carboxylate salt (ire., sodium acetate and the like) and inorganic bases, such as alkali metal carbonates (i.e., lithium carbonate, potassium carbonate and the like). Preferably, the base is a tertiary amine including, by way of illustration, triethylamine, diisopropylethylamine, N-methylmorpholine, and the like. A preferred base is diisopropylethylamine. The base is typically employed in a molar excess relative to vancomycin. Preferably, the base is used in an amount ranging from about 1.5 to about 3 equivalents based on vancomycin; more preferably, about 1.8 to 2.2 equivalents.
When formation of the imine and/or hemiaminal mixture is substantially complete, the reaction mixture is acidified with an excess of acid. Any suitable acid may be employed including, by way of illustration, carboxylic acids (e.g. acetic acid, trichloroacetic acid, citric acid, formic acid, trifluoroacetic acid, methanesulfonic acid, toluenesulfonic acid and the like), mineral acids (e.g. hydrochloric acid, sulfuric acid, or phosphoric acid), and the like. Preferably, the acid is trifluoroacetic acid or acetic acid. The acid is typically added in a molar excess relative to vancomycin (and the base). Preferably, the acid is used in an amount ranging from about 3 to about 6 equivalents based on vancomycin; more preferably, about 3.5 to 5.5 equivalents.
While not wishing to be limited by theory, it is believed that the acid selectively hydrolyzes the imine and/or hemiaminal formed at the N-terminal amine of vancomycin in preference to the imine and/or hemiaminal formed at the vancosamine nitrogen atom. Acidification of the reaction mixture is typically conducted at a temperature ranging from about 0° C. to about 30° C., preferably at about 25° C., for about 0.25 to about 2.0 hours, preferably for about 0.5 to about 1.5 hours. Preferably, a polar, protic solvent is added during this step including, by way of example, methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, and the like. Alternatively, a mixed polar protic/non-protic solvent may be used, such as methanol/tetrahydrofuran, methanol/1,2-dimethoxyethane and the like
After acidification, the reaction mixture is contacted with a reducing agent to reduce the imine and/or hemiaminal. Any suitable reducing agent can be employed which is compatible with the functionality present in the glycopeptide. For example, suitable reducing agents include sodium borohydride, sodium cyanoborohydride, zinc borohydride, sodium triacetoxyborohydride, pyridine/borane, tert-butylamine/borane, N-methylmorpholine/borane, ammonia/borane, dimethylamine/borane, triethylamine/borane, trimethylamine/borane, and the like. Preferred reducing agents are amine/borane complexes such as pyridine/borane and tert-butylamine/borane.
The reduction phase of the reaction is typically conducted at a temperature ranging from about 0° C. to about 30° C., preferably at about 25° C., for about 0.5 to about 24 hours, preferably for about 1 to about 6 hours, or until the reduction is substantially complete. Preferably, a polar, protic solvent is present during this reduction step. The polar, protic solvent is preferably added during the acidification described above.
In contrast to prior procedures, the product of the reductive alkylation process is not isolated but the reaction mixture is contacted with an amine to remove the protecting group (i.e., R 3 ) from the intermediate product. Any suitable amine may be used in this step of the process. Representative amines suitable for use include, by way of example, methylamine, ethylamine, tert-butylamine, triethylamine, piperidine, morpholine, ammonium hydroxide, 1,4-diazabicyclo[2.2.2]octane (DABCO) and the like. Preferred amines are methylamine, tert-butylamine, ammonium hydroxide and 1,4-diazabicyclo[2.2.2]octane.
This deprotection step is typically conducted at a temperature ranging from about 0° C. to about 60° C., preferably at about 40° C. to about 45° C., for about 2 to about 60 hours, preferably for about 3 to about 10 hours, or until the reaction is substantially complete. This step is typically conducted in an inert diluent, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, and the like. The resulting compound of formula IV is readily isolated and purified by conventional procedures, such as precipitation, filtration and the like.
In the next step of the process, the compound of formula IV is contacted with formaldehyde and a compound of formula V:
wherein R 4 is as defined herein; in the presence of a base to provide a compound of formula I, or a salt thereof.
This step of the process is typically conducted by contacting one equivalent of compound IV or a salt thereof with one or more equivalents, preferably with about 2 to about 10 equivalents of a compound of formula V, and with an excess, preferably with about 4 to about 5 equivalents, formaldehyde in the presence of a base.
Phosphonate compounds of formula V are either commercially available or can be prepared by conventional procedures using commercially available starting materials and reagents. See for example, Advanced Organic Chemistry , Jerry March, 4th ed, 1992, John Wiley and Sons, New York, page 959; and Frank R. Hartley (ed.) The Chemistry of Organophosphorous Compounds , vol. 1-4, John Wiley and Sons, New York (1996). Aminomethylphosphonic acid is commercially available from Aldrich Chemical Company, Milwaukee, Wis.
The formaldehyde employed in this step of the process is typically added in an aqueous solution, for example, as a 37 wt. % solution in water optionally containing about 5 to about 15 wt. % methanol (i.e., Formalin).
Any suitable base may be used in this reaction including, for example, organic bases such as tertiary amines, and inorganic bases, such as alkali metal hydroxides (i.e., sodium hydroxide). Preferably, the base is a tertiary amine including, by way of example, triethylamine, diisopropylethylamine, and the like. A preferred tertiary amine is diisopropylethylamine. Preferably, the molar ratio of tertiary amine to compound V is about 3:1 to about 5:1; more preferably, about 3.5:1 to about 4.5:1; and still more preferably, about 4:1. Preferably, the pH of the reaction mixture is preferably about 10 to about 11.
Preferably, this reaction is conducted in an inert diluent, such as water, acetonitrile/water and the like. In a preferred embodiment, this step of the process is conducted in acetonitrile/water or water having v/v ratio ranging from about 3:2 to completely water.
This step of the process is typically conducted at a temperature ranging from about −20° C. to about 20° C., preferably at about −10° C. to about −5° C., for about 6 to about 48 hours, or until the reaction is substantially complete.
The resulting compound of formula I or a salt thereof is isolated by conventional procedures including, precipitation, filtration and the like. In a preferred isolation procedure, the pH of the reaction mixture is adjusted to about 2 to about 3 by addition of a suitable acid, such as aqueous hydrochloride acid. Preferably, the temperature of the reaction mixture is maintained below about 5° C. during acidification. Acetonitrile is then added to promote precipitation of the reaction product (i.e., a compound of formula I) and the resulting precipitate is collected by filtration and optionally washed with additional acetonitrile.
If desired, the reaction product can be further purified using reverse-phase HPLC or other chromatographic methods. In a preferred embodiment, the product is purified using a resin as described in co-pending U.S. application Ser. No. 10/226,676, filed on Aug. 23, 2002; which application claims the benefit of U.S. Provisional Application No. 60/314,712, filed on Aug. 24, 2001; the disclosures of which are incorporated herein by reference in their entirety.
Among other advantages, the process of the present invention provides for improved yield, purity and selectivity, i.e., reductive alkylation at the vancosamine amino group is favored over reductive alkylation at the N-terminus (e.g., the leucinyl group) by at least 10:1, more preferably 20:1. Additionally, because the reductive alkylation and deprotection steps are conducted in a single reaction vessel without isolation of the reaction intermediates, the process of the present invention is more efficient, provides a higher yield and generates less waste then previous processes.
The glycopeptide derivatives produced by the process of this invention are useful as antibiotics. See, for example, U.S. patent application Ser. No. 09/847,042, filed May 1, 2001; the disclosure of which is incorporated herein by reference in its entirety.
Additional details of the process of this invention are described in the following Examples which are offered to illustrate this invention and are not to be construed in any way as limiting the scope of this invention.
EXAMPLES
In the examples below, the following abbreviations have the following meanings. Any abbreviations not defined have their generally accepted meaning. Unless otherwise stated, all temperatures are in degrees Celsius (° C.).
DIPEA=diisopropylethylamine
DMF=N,N-dimethylformamide
DMSO=dimethyl sulfoxide
eq.=equivalent
Fmoc=9-fluorenylmethoxycarbonyl
TFA=trifluoroacetic acid
In the following examples, vancomycin hydrochloride semi-hydrate was purchased from Alpharma, Inc. Fort Lee, N.J. 07024 (Alpharma AS, Oslo Norway). Other reagents and reactants are available from Aldrich Chemical Co., Milwaukee, Wis. 53201.
Example A
Preparation of N-Fmoc-Decylaminoacetaldehyde
Step A
Preparation of N-Fmoc-2-(n-Decylamino)ethanol
2-n-Decylamino)ethanol (2.3 g, 11 mmol, 1.1 eq) and DIPEA (2.0 mL, 11 mmol, 1.1 eq) were dissolved in methylene chloride (15 mL) and cooled in an ice bath. 9-Fluorenylmethyl chloroformate (2.6 g, 10 mmol, 1.0 eq) in methylene chloride (15 ml) was added, the mixture stirred for 30 minutes then washed with 3 N hydrochloric acid (50 mL) twice and saturated sodium bicarbonate (50 mL). The organics were dried over magnesium sulfate, and the solvents removed under reduced pressure. N-Fmoc-2-(n-decylamino)ethanol (4.6 g, 11 mmol, 108%) was used without further purification.
Step B
Preparation of N-Fmoc-2-(n-Decylamino)acetaldehyde
To a solution of oxalyl chloride (12.24 mL) and methylene chloride (50 mL) at −35 to −45° C. was added DMSO (14.75 g) in methylene chloride (25 mL) over 20 minutes. The reaction mixture was stirred for 10 minutes at −35 to −45° C. A solution of N-Fmoc-2-(n-decylamino)ethanol (20.0 g) in methylene chloride (70 mL) was added over 25 minutes and then stirred 40 minutes at −35 to −45° C. Triethylamine (21.49 g) was then added and the mixture stirred for 30 minutes at −10 to −20° C. The reaction mixture was quenched with water (120 mL) followed by concentrated sulfuric acid (20.0 g) while maintaining the internal temperature at 0-5° C. The organic layer was isolated and washed with 2% sulfuric acid (100 mL) followed by water (2×100 mL). The organic solution was distilled under vacuum at 60° C. to about 100 mL. Heptane (100 mL) was added, the temperature of the oil bath raised to 80° C. and the distillation was continued until the residual volume was 100 mL. More heptane (100 mL) was added and the distillation repeated to a volume of 100 mL. The heating bath was replaced with a cold water bath at 15° C. The bath was cooled slowly to 5° C. over 20 minutes to start the precipitation of the product. The slurry was then cooled to −5 to −10° C. and the slurry was stirred for 2 hours. The solid was then collected on a Buchner funnel and washed with cold (−5° C.) heptane (2×15 mL). The wet solid was dried in vacuo to yield the title aldehyde.
Example 1
Preparation of N van -2-(n-Decylamino)ethyl Vancomycin Hydrochloride
To a stirred mixture of 20 g (13.46 mmol) of vancomycin hydrochloride and 6.526 g (15.48 mmol) of N-Fmoc-2-(n-decylamino)acetyldehyde was added 130 mL of N,N-dimethylformamide and 4.7 mL (26.92 mmol) of N,N-diisopropylethylamine. The resulting mixture was stirred at room temperature under nitrogen for 15 hours, and 75 mL of methanol and 4.15 mL of trifluoroacetic acid (53.84 mmol) were added at 0° C. successively. The mixture was stirred for 1 hour and 1.93 mL (15.48 mmol) of borane-pyridine complex was added. The resulting mixture was stirred for 4 hours at 0° C., and 80 mL (161.52 mmol) of a2 M methylamine in methanol was added. The resulting mixture was warmed to room temperature and stirred for 50 hours, cooled to 0° C., and water (350 mL) was added dropwise. The mixture was acidified to pH 3.60 by slow addition of 11 mL of concentrated hydrochloric acid, and precipitation occurred. The mixture was stirred for another 30 min and then it was filtered through a Buchner funnel. The resulting wet cake was washed with water (2×200 mL) and dried in vacuo for 16 hours to give 9.8 g of crude N van -2-(n-decylamino)ethyl vancomycin hydrochloride. This intermediate may then be used in step (c) of the process as described in Example 3.
Example 2
Preparation of N van -2-(n-Decylamino)ethyl Vancomycin Hydrochloride
To a 1L three-necked round bottom flask equipped with a mechanical stirrer, a thermometer and a nitrogen bubbler was added 180 mL of N,N-dimethylformamide (DMF). While stirring, 6.75 g (0.0160 mol) of N-Fmoc-2-(n-decylamino)-acetyldehyde and 25 g (0.0168 mol) of vancomycin hydrochloride were added successively. The addition funnel was rinsed with 20 mL of DMF; and then 5.85 mL (0.0336 mol) of N,N-diisopropylethylamine were added. The resulting mixture was stirred at room temperature under nitrogen for 6-8 hours while maintaining the temperature at 20-25° C. Methanol (95 mL) was added in one portion and then 5.2 mL (0.0672) of trifluoroacetic acid were added within 1 minute. The mixture was stirred for 0.25 hours and then 1.39 g (0.016 mol) of borane-tert-butyl amine complex were added to the reaction mixture in one portion. The addition funnel was rinsed with 5 mL of methanol, and the resulting mixture was stirred for 2 hours at room temperature. tert-Butylamine (10.6 mL, 0.101 mol) was added in one portion and the resulting mixture was stirred at 40-42° C. for about 7 hours. The reaction mixture was then cooled to room temperature and 140 mL of 0.5 N HCl were added, followed by 600 mL of a 10% brine solution at room temperature. The resulting mixture was stirred for 2 hours at 20-25° C., and then cooled to 10° C. and stirred for 1 hour. The resulting precipitate is collected using a 12.5 cm Buchner funnel by filtering the reaction mixture over a period of about 90 min. The wet cake was washed with cold water (2×50 mL) and sucked dry for 5 hours. The resulting material was added to 200 mL of acetonitrile while stirring to 2 hours at 20-25° C. The resulting slurry was filtered through an 8 cm Buchner funnel and the collected wet cake was washed with acetonitrile (2×25 mL) and dried under house vacuum (about 25 mm Hg) for 13 hours to afford 31.1 g of crude N van -2-(n-decylamino)ethyl vancomycin hydrochloride. This intermediate may then be used in step (c) of the process as described in Example 3.
Example 3
Preparation of N van -2-(n-Decylamino)ethyl 29-{[(Phosphonomethyl)amino]methyl}Vancomycin
A 250 mL of three-necked round bottom flask equipped with a mechanical stirrer, a thermometer and a nitrogen outlet was charged with 5 g of N van -2-(n-decylamino)ethyl vancomycin and 1.6 g of aminomethylphosphonic acid and 30 mL of acetonitrile. The slurry was stirred for 15 minutes to allow disperse solids at 20-30° C. and then 20 mL of water was added. The mixture was agitated for 15 minutes and 7.5 g of diisopropylethylamine was added. The resulting mixture was agitated until all solids dissolved. The reaction mixture was then cooled to −5 to −10° C. and 2.5 g of 3.7% aqueous formaldehyde was charged and the resulting mixture was agitated at −5 to −10° C. for 24 hours. The reaction was monitored by HPLC. After the reaction was complete, the reaction mixture was adjusted to pH 2-3 with 3M hydrochloric acid solution while maintaining the reaction temperature at −10 to 5° C. With moderate agitation, 125 mL of acetonitrile was added to the reaction mixture at 20 to 25° C. over 10 minutes. The resulting mixture was stirred at 20 to 25° C. for 2 hours and then filtered. The wet cake was washed with 20 mL of acetonitrile twice and dried for 18 hours in a vacuum oven at 20 to 25° C. to give 5.3 g of the title compound as a mixture of the di- and trihydrochloride salt in ˜100% yield with a purity of ca. 80% (HPLC area) (i.e., a compound of formula I where R 1 is —CH 2 CH 2 —, R 2 is n-decyl and R 4 is —CH 2 —).
Example 4
Preparation of N van -2-(n-Decylamino)ethyl 29-{[(Phosphonomethyl)amino]methyl}Vancomycin
To a 12-L jacketed three-necked flask equipped with a mechanical stirrer, nitrogen inlet and temperature probe was added 117 g (ca. 60 mmol) of N van -2-(n-decylamino)ethyl vancomycin (ca. 80% a purity). Aminomethylphosphonic acid (30 g, 320 mmol) was then added, followed by 420 mL of acetonitrile. The resulting slurry was stirred for 15 minutes and then 426 g of water was added and stirring continued for 15 minutes. Diisopropylethylamine (144 g, 1500 mmol) was added ant the mixture was stirred at room temperature for 1 hour. The resulting light pink solution was cooled to −7° C. (internal temperature) and 4.51 g (60 mmol) of 37% aqueous formaldehyde in 33 mL of acetonitrile were added. The resulting mixture was stirred at −7° C. (internal temperature) for 12 hours while monitoring the reaction by HPLC. After the reaction was complete (i.e., <1% starting material after 12 hours), the pH of the reaction mixture was adjusted from 10.4 to 2.59 by addition of 3 N aqueous hydrochloric acid solution while maintaining the internal reaction temperature at −4 to −5° C. The amount of 3 N aqueous hydrochloride acid used was 455 g. To the resulting mixture was added 3.1 kg of 95% ethanol at 5° C. and the mixture was stirred for 3 hours, and then filtered through a Buchner funnel. The resulting wet cake was washed with 500 g of ethyl acetate to give 135 g of a granular solid. This solid was dried at 30 mmHg at room temperature for 20 hours to give 116 g of the title compound as a mixture of the di- and trihydrochloride salt. Karl Fisher assay of this material showed an 11% water content; and HPLC analysis showed 1.7% unreacted glycopeptide and 3.6% bis-Mannich byproduct relative to the title compound.
While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto. Additionally, all publications, patents, and patent documents cited hereinabove are incorporated by reference herein in full, as though individually incorporated by reference. | Disclosed are processes for preparing glycopeptide phosphonate derivatives having an amino-containing side chain. Several of the process steps are conducted in a single reaction vessel without isolation of intermediate reaction products, thereby generating less waste and improving the overall efficiency and yield of the process. | Provide a concise summary of the essential information conveyed in the given context. | [
"CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. application Ser.",
"No. 10/926,148, filed Aug. 25, 2004 now U.S Pat. No. 7,074,890;",
"which application is a continuation of U.S. application Ser.",
"No. 10/226,428, filed Aug. 23, 2002 (now U.S. Pat. No. 6,979,723);",
"which application claims the benefit of U.S. Provisional Application No. 60/314,831, filed on Aug. 24, 2001;",
"the entire disclosures of which are incorporated herein by reference in their entirety.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention This invention is directed to novel processes for preparing derivatives of glycopeptide antibiotics.",
"More specifically, this invention is directed to multi-step processes for preparing phosphonate derivatives of glycopeptide antibiotics having an amino-containing side chain, the first two steps being conducted in a single reaction vessel without isolation of the intermediate reaction products.",
"Background Glycopeptides (e.g. dalbaheptides) are a well-known class of antibiotics produced by various microorganisms (see Glycopeptide Antibiotics , edited by R. Nagarajan, Marcel Dekker, Inc. New York (1994)).",
"Many synthetic derivatives of such glycopeptides are also known in the art and these derivatives are typically reported to have improved properties relative to the naturally-occurring glycopeptides, including enhanced antibacterial activity.",
"For example, U.S. patent application Ser.",
"No. 09/847,042, filed May 1, 2001, describes various glycopeptide phosphonate derivatives, some of which contain an amino-containing side chain.",
"Such phosphate derivatives are particularly useful as antibiotics for treating gram-positive infections.",
"Accordingly, a need exists for new efficient processes which are useful for preparing phosphonate derivatives of glycopeptide antibiotics having an amino-containing side chain.",
"SUMMARY OF THE INVENTION The present invention provides novel processes for preparing phosphonate derivatives of glycopeptide antibiotics having an amino-containing side chain.",
"Among other advantages, the first two steps of the present process are conducted in a single reaction vessel without isolation of the intermediate reaction products, thereby generating less waste and improving the overall efficiency and yield of the process compared to previous processes.",
"Specifically, in one of its aspects, this invention is directed to a process for preparing a compound of formula 1: wherein R 1 is selected from the group consisting of C 1-10 alkylene, C 2-10 alkenylene and C 2-10 alkynylene;",
"R 2 is selected from the group consisting of C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, C 3-8 cycloalkyl, C 5-8 cycloalkenyl, C 6-10 aryl, C 2-9 heteroaryl, C 2-9 heterocyclic, —R a -Cy 1 , —R a —Ar 1 —Ar 2 , —R a —Ar 1 —R b —Ar 2 , —R a —Ar 1 —O—R b —Ar 2 ;",
"R 4 is C 1-10 alkylene;",
"R a is selected from the group consisting of C 1-10 alkylene, C 1-10 alkenylene and C 1-10 alkynylene;",
"R b is selected from the group consisting of C 1-6 alkylene, C 1-6 alkenylene and C 1-6 alkynylene;",
"Cy 1 is selected from the group consisting of C 3-8 cycloalkyl, C 5-8 cycloalkenyl, C 6-10 aryl, C 2-9 heteroaryl, C 2-9 heterocyclic;",
"Ar 1 and Ar 2 are independently selected from C 6-10 aryl and C 2-9 heteroaryl;",
"wherein each aryl, heteroaryl and heterocyclic group is optionally substituted with 1 to 3 substituents independently selected from the group consisting of C 1-6 alkyl, C 1-6 alkoxy, halo, hydroxy, nitro and trifluoromethyl, and each heteroaryl and heterocyclic group contains from 1 to 3 heteroatoms selected from nitrogen, oxygen or sulfur;",
"or a salt thereof;",
"the process comprising: (a) reacting vancomycin or a salt thereof, with a compound of formula II: wherein R 1 and R 2 are as defined herein;",
"and R 3 is a amine-labile protecting group;",
"and a reducing agent to form a compound of formula III: wherein R 1 , R 2 and R 3 are as defined herein or a salt thereof;",
"(b) reacting the compound of formula III with an amine to provide a compound of formula IV: wherein R 1 and R 2 are as defined herein, or a salt thereof;",
"wherein step (a) and step (b) are conducted in the same reaction mixture without isolation of the intermediate from step (a);",
"and (c) reacting the compound of formula IV with formaldehyde and a compound of formula V: in the presence of a base to provide a compound of formula I, or a salt thereof.",
"In the above process, R 1 is preferably C 1-6 alkylene.",
"More preferably, R 1 is C 1-2 alkylene.",
"Still more preferably, R 1 is —CH 2 —.",
"R 2 is preferably C 6-14 alkyl.",
"More preferably, R 2 is C 8-12 alkyl.",
"Still more preferably, R 2 is n-decyl.",
"In the process of this invention, R 3 is an amino-protecting group which is removed by treatment with an amine (i.e., a nucleophilic amine).",
"Preferably, R 3 is a group of formula (A): W—OC(O)— (A) wherein W is selected from the group consisting of 9-fluorenylmethyl, 3-indenylmethyl, benz[f]inden-3-ylmethyl, 17-tetrabenzo[a,c,g,i]fluorenylmethyl, 2,7-di-tert-butyl[9-(10,10-dioxo-10,10,10,10-tetrahydrothioxanthyl)]methyl, 1,1-dioxobenzo[b]thiophene-2-ylmethyl, wherein the 9-fluorenylmethyl group is optionally substituted with 1 to 3 substitutents selected from the group consisting of C 1-6 alkyl, halo, nitro and sulfo.",
"Preferably, W is 9-fluorenylmethyl, wherein the 9-fluorenylmethyl group is optionally substituted with 1 to 3 substitutents selected from the group consisting of C 1-6 alkyl, halo, nitro and sulfo.",
"More preferably, W is 9-fluorenylmethyl.",
"Preferably, R 4 is C 1-6 alkylene.",
"More preferably, R 4 is C 1-4 alkylene.",
"Still more preferably, R 4 is —CH 2 —.",
"In step (a), the reducing agent is preferably an amine/borane complex.",
"More preferably, the reducing agent is pyridine/borane or tert-butylamine/borane;",
"and still more preferably, the reducing agent is tert-butylamine/borane.",
"In a preferred embodiment of this process, step (a) comprises the steps of: (i) combining vancomycin or a salt thereof with a compound of formula II in the presence of base to form a reaction mixture;",
"(ii) acidifying the reaction mixture from step (i) with an acid;",
"and (iii) contacting the reaction mixture from step (ii) with a reducing agent.",
"In this preferred embodiment, the base in step (i) is preferably a tertiary amine;",
"more preferably, the base is diisopropylethylamine.",
"Preferably, the acid employed in step (ii) is trifluoroacetic acid or acetic acid.",
"In step (b), the amine employed is preferably ammonium hydroxide or a primary amine.",
"More preferably, the amine is ammonium hydroxide, methylamine or tert-butylamine;",
"and still more preferably, the amine is tert-butylamine.",
"In step (c), the base employed is preferably a tertiary amine.",
"Preferably, the tertiary amine employed is diisopropylethylamine.",
"In a preferred embodiment, the molar ratio of tertiary amine to compound of formula V is about 3:1 to about 5:1;",
"more preferably, about 4:1.",
"DETAILED DESCRIPTION OF THE INVENTION This invention relates to novel processes for preparing glycopeptide phosphonate derivatives having an amino-containing side chain.",
"When describing such processes, the following terms have the following meanings, unless otherwise indicated.",
"DEFINITIONS The term “alkyl”",
"refers to a monovalent saturated hydrocarbon group which may be linear or branched.",
"Unless otherwise defined, such alkyl groups typically contain from 1 to 20 carbon atoms.",
"Representative alkyl groups include, by way of example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl and the like.",
"The term “alkenyl”",
"refers to a monovalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon double bonds.",
"Unless otherwise defined, such alkenyl groups typically contain from 2 to 20 carbon atoms.",
"Representative alkenyl groups include, by way of example, ethenyl, n-propenyl, isopropenyl, n-but-2-enyl, n-hex-3-enyl and the like.",
"The term “alkynyl”",
"refers to a monovalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon triple bonds.",
"Unless otherwise defined, such alkynyl groups typically contain from 2 to 20 carbon atoms.",
"Representative alkynyl groups include, by way of example, ethynyl, n-propynyl, n-but-2-ynyl, n-hex-3-ynyl and the like.",
"The term “alkylene”",
"refers to a divalent saturated hydrocarbon group which may be linear or branched.",
"Unless otherwise defined, such alkylene groups typically contain from 1 to 10 carbon atoms.",
"Representative alkylene groups include, by way of example, methylene, ethane-1,2-diyl (“ethylene”), propane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl and the like.",
"The term “alkenylene”",
"refers to a divalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon double bonds.",
"Unless otherwise defined, such alkenylene groups typically contain from 2 to 10 carbon atoms.",
"Representative alkenylene groups include, by way of example, ethene-1,2-diyl, prop-1-ene-1,2-diyl, prop-1-ene-1,3-diyl, but-2-ene-1,4-diyl, and the like.",
"The term “alkynylene”",
"refers to a divalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon triple bonds.",
"Unless otherwise defined, such alkynylene groups typically contain from 2 to 10 carbon atoms.",
"Representative alkynylene groups include, by way of example, ethyne-1,2-diyl, prop-1-yne-1,2-diyl, prop-1-yne-1,3-diyl, but-2-yne-1,4diyl, and the like.",
"The term “alkoxy”",
"refers to a group of the formula —O—R, where R is alkyl as defined herein.",
"Representative alkoxy groups include, by way of example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy and the like.",
"The term “aryl”",
"refers to a monovalent aromatic hydrocarbon having a single ring (i.e., phenyl) or fused rings (i.e., naphthalene).",
"Unless otherwise defined, such aryl groups typically contain from 6 to 10 carbon ring atoms.",
"Representative aryl groups include, by way of example, phenyl and naphthalene-1-yl, naphthalene-2-yl, and the like.",
"The term “cycloalkyl”",
"refers to a monovalent saturated carbocyclic hydrocarbon group.",
"Unless otherwise defined, such cycloalkyl groups typically contain from 3 to 10 carbon atoms.",
"Representative cycloalkyl groups include, by way of example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like.",
"The term “cycloalkenyl”",
"refers to a monovalent unsaturated carbocyclic hydrocarbon group having at least one carbon-carbon double bond in the carbocyclic ring.",
"Unless otherwise defined, such cycloalkenyl groups typically contain from 5 to 10 carbon atoms.",
"Representative cycloalkenyl groups include, by way of example, cyclopent-3-en-1-yl, cyclohex-1-en-1-yl and the like.",
"The term “halo”",
"refers to fluoro, chloro, bromo and iodo;",
"preferably, chloro, bromo and iodo.",
"The term “heteroaryl”",
"refers to a monovalent aromatic group having a single ring or two fused rings and containing in the ring at least one heteroatom (typically 1 to 3 heteroatoms) selected from nitrogen, oxygen or sulfur.",
"Unless otherwise defined, such heteroaryl groups typically contain from 5 to 10 total ring atoms.",
"Representative heteroaryl groups include, by way of example, monovalent species of pyrrole, imidazole, thiazole, oxazole, fur, thiophene, triazole, pyrazole, isoxazole, isothiazole, pyridine, pyrazine, pyridazine, pyrimidine, triazine, indole, benzofuran, benzothiophene, benzimidazole, benzthiazole, quinoline, isoquinoline, quinazoline, quinoxaline and the like, where the point of attachment is at any available carbon or nitrogen ring atom.",
"The term “heterocycle”",
"or “heterocyclic”",
"refers to a monovalent saturated or unsaturated (non-aromatic) group having a single ring or multiple condensed rings and containing in the ring at least one heteroatom (typically 1 to 3 heteroatoms) selected from nitrogen, oxygen or sulfur.",
"Unless otherwise defined, such heterocyclic groups typically contain from 2 to 9 total ring atoms.",
"Representative heterocyclic groups include, by way of example, monovalent species of pyrrolidine, imidazolidine, pyrazolidine, piperidine, 1,4-dioxane, morpholine, thiomorpholine, piperazine, 3-pyrroline and the like, where the point of attachment is at any available carbon or nitrogen ring atom.",
"The term “vancomycin”",
"is used herein in its art recognized manner to refer to the glycopeptide antibiotic known as vancomycin.",
"See, for example, R. Nagarajan, “Glycopeptide Anitibiotics”, Marcel Dekker, Inc. (1994) and references cited therein.",
"The designation “N van -”",
"refers to substitution at the vancosamine nitrogen atom of vancomycin.",
"This position is also referred to as the N3″ position of vancomycin.",
"Additionally, using a conventional vancomycin numbering system, the designation “29-”",
"refers to the carbon atom position between the two hydroxyl groups on the phenyl ring of amino acid 7 (AA-7).",
"This position is also sometimes referred to as the “7d”",
"or the “resorcinol position”",
"of vancomycin.",
"The term “salt”",
"when used in conjunction with a compound referred to herein refers to a salt of the compound derived from an inorganic or organic base or from an inorganic or organic acid.",
"Salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic, manganous, potassium, sodium, zinc and the like.",
"Particularly preferred are ammonium, calcium, magnesium, potassium and sodium salts.",
"Salts derived from organic bases include salts of primary, secondary and tertiary amines, including substituted amines, cyclic amines, naturally occuring amines and the like, such as arginine, betaine, caffeine, choline, N,N′-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperadine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine and the like.",
"Salts derived from acids include acetic, ascorbic, benzenesulfonic, benzoic, camphosulfonic, citric, ethanesulfonic, fumaric, gluconic, glucoronic, glutamic, hippuric, hydrobromic, hydrochloric, isethionic, lactic, lactobionic, maleic, malic, mandelic, methanesulfonic, mucic, naphthalenesulfonic, nicotinic, nitric, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic and the like.",
"Particularly preferred are citric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric and tartaric acids.",
"The term “protecting group”",
"or “blocking group”",
"refers to a group which, when covalently attached to a function group such as an amino, hydroxyl, thiol, carboxyl, carbonyl and the like, prevents the functional group from undergoing undesired reactions but which permits the function group to be regenerated (i.e., deprotected or unblocked) upon treatment of the protecting group with a suitable reagent.",
"Representative protecting groups are disclosed, for example, in T. W. Greene and P. G. M. Wuts, “Protective Groups in Organic Synthesis”",
"3rd Ed.",
", 1999, John Wiley and Sons, N.Y. The term “amine-labile protecting group”",
"refers to a protecting group which is removed upon treatment with a suitable amine.",
"Process Conditions The process of the present invention is conducted in three steps beginning with vancomycin or a salt thereof.",
"The first step of the process is a reductive alkylation step which involves first combining one equivalent of vancomycin or a salt thereof, with one or more equivalents of an aldehyde of formula II: wherein R 1 , R 2 and R 3 are as defined herein to form a imine and/or hemiaminal intermediate in situ.",
"The aldehydes of formula II employed in the process of the present invention are well-known in the art and are either commercially available or can be prepared by conventional procedures using commercially available starting materials and conventional reagents.",
"For example, see WO 00/39156, published on Jul. 6, 2000, which describes various methods for preparing such aldehydes.",
"Typically, the vancomycin or a salt thereof and the aldehyde are combined in an inert diluent in the presence of an excess amount of a suitable base to form a reaction mixture.",
"Preferably, the inert diluent is N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, acetonitrile/water, and the like or mixtures thereof Preferably, from about 1 to about 2 equivalents of the aldehyde are employed;",
"more preferably, about 1.1 to about 1.2 equivalents.",
"In this reaction mixture, a mixture of imines and/or hemiaminals is believed to be formed between the aldehyde and the basic nitrogen atoms of vancomycin, i.e., the vancosamine nitrogen atom and the N-terminal (leucinyl) nitrogen atom.",
"Formation of the imine and/or hemiaminal intermediate is typically conducted at a temperature ranging from about 0° C. to about 75° C., preferably at ambient temperature (i.e., about 20-25° C.) for about 1 to about 24 hours, preferably for about 6 to 12 hours, or until formation of the imine and/or hemiaminal is substantially complete.",
"Any suitable base may be employed to neutralize the vancomycin salt and to facilitate formation of the imine and/or hemiaminal, including organic bases, such as amines, alkali metal carboxylate salt (ire.",
", sodium acetate and the like) and inorganic bases, such as alkali metal carbonates (i.e., lithium carbonate, potassium carbonate and the like).",
"Preferably, the base is a tertiary amine including, by way of illustration, triethylamine, diisopropylethylamine, N-methylmorpholine, and the like.",
"A preferred base is diisopropylethylamine.",
"The base is typically employed in a molar excess relative to vancomycin.",
"Preferably, the base is used in an amount ranging from about 1.5 to about 3 equivalents based on vancomycin;",
"more preferably, about 1.8 to 2.2 equivalents.",
"When formation of the imine and/or hemiaminal mixture is substantially complete, the reaction mixture is acidified with an excess of acid.",
"Any suitable acid may be employed including, by way of illustration, carboxylic acids (e.g. acetic acid, trichloroacetic acid, citric acid, formic acid, trifluoroacetic acid, methanesulfonic acid, toluenesulfonic acid and the like), mineral acids (e.g. hydrochloric acid, sulfuric acid, or phosphoric acid), and the like.",
"Preferably, the acid is trifluoroacetic acid or acetic acid.",
"The acid is typically added in a molar excess relative to vancomycin (and the base).",
"Preferably, the acid is used in an amount ranging from about 3 to about 6 equivalents based on vancomycin;",
"more preferably, about 3.5 to 5.5 equivalents.",
"While not wishing to be limited by theory, it is believed that the acid selectively hydrolyzes the imine and/or hemiaminal formed at the N-terminal amine of vancomycin in preference to the imine and/or hemiaminal formed at the vancosamine nitrogen atom.",
"Acidification of the reaction mixture is typically conducted at a temperature ranging from about 0° C. to about 30° C., preferably at about 25° C., for about 0.25 to about 2.0 hours, preferably for about 0.5 to about 1.5 hours.",
"Preferably, a polar, protic solvent is added during this step including, by way of example, methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, and the like.",
"Alternatively, a mixed polar protic/non-protic solvent may be used, such as methanol/tetrahydrofuran, methanol/1,2-dimethoxyethane and the like After acidification, the reaction mixture is contacted with a reducing agent to reduce the imine and/or hemiaminal.",
"Any suitable reducing agent can be employed which is compatible with the functionality present in the glycopeptide.",
"For example, suitable reducing agents include sodium borohydride, sodium cyanoborohydride, zinc borohydride, sodium triacetoxyborohydride, pyridine/borane, tert-butylamine/borane, N-methylmorpholine/borane, ammonia/borane, dimethylamine/borane, triethylamine/borane, trimethylamine/borane, and the like.",
"Preferred reducing agents are amine/borane complexes such as pyridine/borane and tert-butylamine/borane.",
"The reduction phase of the reaction is typically conducted at a temperature ranging from about 0° C. to about 30° C., preferably at about 25° C., for about 0.5 to about 24 hours, preferably for about 1 to about 6 hours, or until the reduction is substantially complete.",
"Preferably, a polar, protic solvent is present during this reduction step.",
"The polar, protic solvent is preferably added during the acidification described above.",
"In contrast to prior procedures, the product of the reductive alkylation process is not isolated but the reaction mixture is contacted with an amine to remove the protecting group (i.e., R 3 ) from the intermediate product.",
"Any suitable amine may be used in this step of the process.",
"Representative amines suitable for use include, by way of example, methylamine, ethylamine, tert-butylamine, triethylamine, piperidine, morpholine, ammonium hydroxide, 1,4-diazabicyclo[2.2[.",
"].2]octane (DABCO) and the like.",
"Preferred amines are methylamine, tert-butylamine, ammonium hydroxide and 1,4-diazabicyclo[2.2[.",
"].2]octane.",
"This deprotection step is typically conducted at a temperature ranging from about 0° C. to about 60° C., preferably at about 40° C. to about 45° C., for about 2 to about 60 hours, preferably for about 3 to about 10 hours, or until the reaction is substantially complete.",
"This step is typically conducted in an inert diluent, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, and the like.",
"The resulting compound of formula IV is readily isolated and purified by conventional procedures, such as precipitation, filtration and the like.",
"In the next step of the process, the compound of formula IV is contacted with formaldehyde and a compound of formula V: wherein R 4 is as defined herein;",
"in the presence of a base to provide a compound of formula I, or a salt thereof.",
"This step of the process is typically conducted by contacting one equivalent of compound IV or a salt thereof with one or more equivalents, preferably with about 2 to about 10 equivalents of a compound of formula V, and with an excess, preferably with about 4 to about 5 equivalents, formaldehyde in the presence of a base.",
"Phosphonate compounds of formula V are either commercially available or can be prepared by conventional procedures using commercially available starting materials and reagents.",
"See for example, Advanced Organic Chemistry , Jerry March, 4th ed, 1992, John Wiley and Sons, New York, page 959;",
"and Frank R. Hartley (ed.) The Chemistry of Organophosphorous Compounds , vol.",
"1-4, John Wiley and Sons, New York (1996).",
"Aminomethylphosphonic acid is commercially available from Aldrich Chemical Company, Milwaukee, Wis.",
"The formaldehyde employed in this step of the process is typically added in an aqueous solution, for example, as a 37 wt.",
"% solution in water optionally containing about 5 to about 15 wt.",
"% methanol (i.e., Formalin).",
"Any suitable base may be used in this reaction including, for example, organic bases such as tertiary amines, and inorganic bases, such as alkali metal hydroxides (i.e., sodium hydroxide).",
"Preferably, the base is a tertiary amine including, by way of example, triethylamine, diisopropylethylamine, and the like.",
"A preferred tertiary amine is diisopropylethylamine.",
"Preferably, the molar ratio of tertiary amine to compound V is about 3:1 to about 5:1;",
"more preferably, about 3.5:1 to about 4.5:1;",
"and still more preferably, about 4:1.",
"Preferably, the pH of the reaction mixture is preferably about 10 to about 11.",
"Preferably, this reaction is conducted in an inert diluent, such as water, acetonitrile/water and the like.",
"In a preferred embodiment, this step of the process is conducted in acetonitrile/water or water having v/v ratio ranging from about 3:2 to completely water.",
"This step of the process is typically conducted at a temperature ranging from about −20° C. to about 20° C., preferably at about −10° C. to about −5° C., for about 6 to about 48 hours, or until the reaction is substantially complete.",
"The resulting compound of formula I or a salt thereof is isolated by conventional procedures including, precipitation, filtration and the like.",
"In a preferred isolation procedure, the pH of the reaction mixture is adjusted to about 2 to about 3 by addition of a suitable acid, such as aqueous hydrochloride acid.",
"Preferably, the temperature of the reaction mixture is maintained below about 5° C. during acidification.",
"Acetonitrile is then added to promote precipitation of the reaction product (i.e., a compound of formula I) and the resulting precipitate is collected by filtration and optionally washed with additional acetonitrile.",
"If desired, the reaction product can be further purified using reverse-phase HPLC or other chromatographic methods.",
"In a preferred embodiment, the product is purified using a resin as described in co-pending U.S. application Ser.",
"No. 10/226,676, filed on Aug. 23, 2002;",
"which application claims the benefit of U.S. Provisional Application No. 60/314,712, filed on Aug. 24, 2001;",
"the disclosures of which are incorporated herein by reference in their entirety.",
"Among other advantages, the process of the present invention provides for improved yield, purity and selectivity, i.e., reductive alkylation at the vancosamine amino group is favored over reductive alkylation at the N-terminus (e.g., the leucinyl group) by at least 10:1, more preferably 20:1.",
"Additionally, because the reductive alkylation and deprotection steps are conducted in a single reaction vessel without isolation of the reaction intermediates, the process of the present invention is more efficient, provides a higher yield and generates less waste then previous processes.",
"The glycopeptide derivatives produced by the process of this invention are useful as antibiotics.",
"See, for example, U.S. patent application Ser.",
"No. 09/847,042, filed May 1, 2001;",
"the disclosure of which is incorporated herein by reference in its entirety.",
"Additional details of the process of this invention are described in the following Examples which are offered to illustrate this invention and are not to be construed in any way as limiting the scope of this invention.",
"EXAMPLES In the examples below, the following abbreviations have the following meanings.",
"Any abbreviations not defined have their generally accepted meaning.",
"Unless otherwise stated, all temperatures are in degrees Celsius (° C.).",
"DIPEA=diisopropylethylamine DMF=N,N-dimethylformamide DMSO=dimethyl sulfoxide eq.",
"=equivalent Fmoc=9-fluorenylmethoxycarbonyl TFA=trifluoroacetic acid In the following examples, vancomycin hydrochloride semi-hydrate was purchased from Alpharma, Inc. Fort Lee, N.J. 07024 (Alpharma AS, Oslo Norway).",
"Other reagents and reactants are available from Aldrich Chemical Co., Milwaukee, Wis.",
"53201.",
"Example A Preparation of N-Fmoc-Decylaminoacetaldehyde Step A Preparation of N-Fmoc-2-(n-Decylamino)ethanol 2-n-Decylamino)ethanol (2.3 g, 11 mmol, 1.1 eq) and DIPEA (2.0 mL, 11 mmol, 1.1 eq) were dissolved in methylene chloride (15 mL) and cooled in an ice bath.",
"9-Fluorenylmethyl chloroformate (2.6 g, 10 mmol, 1.0 eq) in methylene chloride (15 ml) was added, the mixture stirred for 30 minutes then washed with 3 N hydrochloric acid (50 mL) twice and saturated sodium bicarbonate (50 mL).",
"The organics were dried over magnesium sulfate, and the solvents removed under reduced pressure.",
"N-Fmoc-2-(n-decylamino)ethanol (4.6 g, 11 mmol, 108%) was used without further purification.",
"Step B Preparation of N-Fmoc-2-(n-Decylamino)acetaldehyde To a solution of oxalyl chloride (12.24 mL) and methylene chloride (50 mL) at −35 to −45° C. was added DMSO (14.75 g) in methylene chloride (25 mL) over 20 minutes.",
"The reaction mixture was stirred for 10 minutes at −35 to −45° C. A solution of N-Fmoc-2-(n-decylamino)ethanol (20.0 g) in methylene chloride (70 mL) was added over 25 minutes and then stirred 40 minutes at −35 to −45° C. Triethylamine (21.49 g) was then added and the mixture stirred for 30 minutes at −10 to −20° C. The reaction mixture was quenched with water (120 mL) followed by concentrated sulfuric acid (20.0 g) while maintaining the internal temperature at 0-5° C. The organic layer was isolated and washed with 2% sulfuric acid (100 mL) followed by water (2×100 mL).",
"The organic solution was distilled under vacuum at 60° C. to about 100 mL.",
"Heptane (100 mL) was added, the temperature of the oil bath raised to 80° C. and the distillation was continued until the residual volume was 100 mL.",
"More heptane (100 mL) was added and the distillation repeated to a volume of 100 mL.",
"The heating bath was replaced with a cold water bath at 15° C. The bath was cooled slowly to 5° C. over 20 minutes to start the precipitation of the product.",
"The slurry was then cooled to −5 to −10° C. and the slurry was stirred for 2 hours.",
"The solid was then collected on a Buchner funnel and washed with cold (−5° C.) heptane (2×15 mL).",
"The wet solid was dried in vacuo to yield the title aldehyde.",
"Example 1 Preparation of N van -2-(n-Decylamino)ethyl Vancomycin Hydrochloride To a stirred mixture of 20 g (13.46 mmol) of vancomycin hydrochloride and 6.526 g (15.48 mmol) of N-Fmoc-2-(n-decylamino)acetyldehyde was added 130 mL of N,N-dimethylformamide and 4.7 mL (26.92 mmol) of N,N-diisopropylethylamine.",
"The resulting mixture was stirred at room temperature under nitrogen for 15 hours, and 75 mL of methanol and 4.15 mL of trifluoroacetic acid (53.84 mmol) were added at 0° C. successively.",
"The mixture was stirred for 1 hour and 1.93 mL (15.48 mmol) of borane-pyridine complex was added.",
"The resulting mixture was stirred for 4 hours at 0° C., and 80 mL (161.52 mmol) of a2 M methylamine in methanol was added.",
"The resulting mixture was warmed to room temperature and stirred for 50 hours, cooled to 0° C., and water (350 mL) was added dropwise.",
"The mixture was acidified to pH 3.60 by slow addition of 11 mL of concentrated hydrochloric acid, and precipitation occurred.",
"The mixture was stirred for another 30 min and then it was filtered through a Buchner funnel.",
"The resulting wet cake was washed with water (2×200 mL) and dried in vacuo for 16 hours to give 9.8 g of crude N van -2-(n-decylamino)ethyl vancomycin hydrochloride.",
"This intermediate may then be used in step (c) of the process as described in Example 3.",
"Example 2 Preparation of N van -2-(n-Decylamino)ethyl Vancomycin Hydrochloride To a 1L three-necked round bottom flask equipped with a mechanical stirrer, a thermometer and a nitrogen bubbler was added 180 mL of N,N-dimethylformamide (DMF).",
"While stirring, 6.75 g (0.0160 mol) of N-Fmoc-2-(n-decylamino)-acetyldehyde and 25 g (0.0168 mol) of vancomycin hydrochloride were added successively.",
"The addition funnel was rinsed with 20 mL of DMF;",
"and then 5.85 mL (0.0336 mol) of N,N-diisopropylethylamine were added.",
"The resulting mixture was stirred at room temperature under nitrogen for 6-8 hours while maintaining the temperature at 20-25° C. Methanol (95 mL) was added in one portion and then 5.2 mL (0.0672) of trifluoroacetic acid were added within 1 minute.",
"The mixture was stirred for 0.25 hours and then 1.39 g (0.016 mol) of borane-tert-butyl amine complex were added to the reaction mixture in one portion.",
"The addition funnel was rinsed with 5 mL of methanol, and the resulting mixture was stirred for 2 hours at room temperature.",
"tert-Butylamine (10.6 mL, 0.101 mol) was added in one portion and the resulting mixture was stirred at 40-42° C. for about 7 hours.",
"The reaction mixture was then cooled to room temperature and 140 mL of 0.5 N HCl were added, followed by 600 mL of a 10% brine solution at room temperature.",
"The resulting mixture was stirred for 2 hours at 20-25° C., and then cooled to 10° C. and stirred for 1 hour.",
"The resulting precipitate is collected using a 12.5 cm Buchner funnel by filtering the reaction mixture over a period of about 90 min.",
"The wet cake was washed with cold water (2×50 mL) and sucked dry for 5 hours.",
"The resulting material was added to 200 mL of acetonitrile while stirring to 2 hours at 20-25° C. The resulting slurry was filtered through an 8 cm Buchner funnel and the collected wet cake was washed with acetonitrile (2×25 mL) and dried under house vacuum (about 25 mm Hg) for 13 hours to afford 31.1 g of crude N van -2-(n-decylamino)ethyl vancomycin hydrochloride.",
"This intermediate may then be used in step (c) of the process as described in Example 3.",
"Example 3 Preparation of N van -2-(n-Decylamino)ethyl 29-{[(Phosphonomethyl)amino]methyl}Vancomycin A 250 mL of three-necked round bottom flask equipped with a mechanical stirrer, a thermometer and a nitrogen outlet was charged with 5 g of N van -2-(n-decylamino)ethyl vancomycin and 1.6 g of aminomethylphosphonic acid and 30 mL of acetonitrile.",
"The slurry was stirred for 15 minutes to allow disperse solids at 20-30° C. and then 20 mL of water was added.",
"The mixture was agitated for 15 minutes and 7.5 g of diisopropylethylamine was added.",
"The resulting mixture was agitated until all solids dissolved.",
"The reaction mixture was then cooled to −5 to −10° C. and 2.5 g of 3.7% aqueous formaldehyde was charged and the resulting mixture was agitated at −5 to −10° C. for 24 hours.",
"The reaction was monitored by HPLC.",
"After the reaction was complete, the reaction mixture was adjusted to pH 2-3 with 3M hydrochloric acid solution while maintaining the reaction temperature at −10 to 5° C. With moderate agitation, 125 mL of acetonitrile was added to the reaction mixture at 20 to 25° C. over 10 minutes.",
"The resulting mixture was stirred at 20 to 25° C. for 2 hours and then filtered.",
"The wet cake was washed with 20 mL of acetonitrile twice and dried for 18 hours in a vacuum oven at 20 to 25° C. to give 5.3 g of the title compound as a mixture of the di- and trihydrochloride salt in ˜100% yield with a purity of ca.",
"80% (HPLC area) (i.e., a compound of formula I where R 1 is —CH 2 CH 2 —, R 2 is n-decyl and R 4 is —CH 2 —).",
"Example 4 Preparation of N van -2-(n-Decylamino)ethyl 29-{[(Phosphonomethyl)amino]methyl}Vancomycin To a 12-L jacketed three-necked flask equipped with a mechanical stirrer, nitrogen inlet and temperature probe was added 117 g (ca.",
"60 mmol) of N van -2-(n-decylamino)ethyl vancomycin (ca.",
"80% a purity).",
"Aminomethylphosphonic acid (30 g, 320 mmol) was then added, followed by 420 mL of acetonitrile.",
"The resulting slurry was stirred for 15 minutes and then 426 g of water was added and stirring continued for 15 minutes.",
"Diisopropylethylamine (144 g, 1500 mmol) was added ant the mixture was stirred at room temperature for 1 hour.",
"The resulting light pink solution was cooled to −7° C. (internal temperature) and 4.51 g (60 mmol) of 37% aqueous formaldehyde in 33 mL of acetonitrile were added.",
"The resulting mixture was stirred at −7° C. (internal temperature) for 12 hours while monitoring the reaction by HPLC.",
"After the reaction was complete (i.e., <1% starting material after 12 hours), the pH of the reaction mixture was adjusted from 10.4 to 2.59 by addition of 3 N aqueous hydrochloric acid solution while maintaining the internal reaction temperature at −4 to −5° C. The amount of 3 N aqueous hydrochloride acid used was 455 g. To the resulting mixture was added 3.1 kg of 95% ethanol at 5° C. and the mixture was stirred for 3 hours, and then filtered through a Buchner funnel.",
"The resulting wet cake was washed with 500 g of ethyl acetate to give 135 g of a granular solid.",
"This solid was dried at 30 mmHg at room temperature for 20 hours to give 116 g of the title compound as a mixture of the di- and trihydrochloride salt.",
"Karl Fisher assay of this material showed an 11% water content;",
"and HPLC analysis showed 1.7% unreacted glycopeptide and 3.6% bis-Mannich byproduct relative to the title compound.",
"While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention.",
"In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present invention.",
"All such modifications are intended to be within the scope of the claims appended hereto.",
"Additionally, all publications, patents, and patent documents cited hereinabove are incorporated by reference herein in full, as though individually incorporated by reference."
] |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No. 11/741,475 filed Apr. 27, 2007.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
none
REFERENCE TO A “SEQUENCE LISTING”
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the actuation of electromagnetic clutches and more particularly to a controller for such clutches that reduces the stresses associated with engagement of the clutches by providing a progressive or soft start.
2. Description of Related Art
Electromagnetic clutches are used in a variety of applications, including coupling large and small engines and motors to equipment operated by the engines or motors either directly or through transmissions. Especially in the case of relatively small engines and motors, the price of clutch controllers is a significant factor in the implementation of such controllers. However, small engine applications also benefit significantly from controlling the abrupt engagement of clutches since such engagement may increase wear, cause undesirable operating characteristics such as jerking, or cause the engine to stall if the clutch is engaged abruptly.
There have, in the past, been some efforts made towards reducing the abruptness of clutch engagement. Such methods have taken various forms, including mechanical arrangements that suffer from the disadvantage that they are complex and expensive, and electrical arrangements such as a simple switch that have provided less than optimal results. This invention provides a simple and inexpensive method for soft starting an electromagnetic clutch.
In almost all instances, an electromagnetic clutch includes a coil or solenoid through which a current is passed to actuate the clutch, an at least partially ferrous core is arranged to be drawn into the magnetic circuit when current is supplied to the coil. The coil typically resides inside a metal drum directly connected to the engine output shaft. The coil is stationary, but is magnetically coupled to the spinning drum. The armature core usually consists of the clutch disk itself, which is mechanically connected to the output shaft of the clutch assembly and is separated from the driven side by an “air-gap.” As current is applied to the coil, the magnetic field of the coil builds as the drum is magnetized to the point where the output disk (armature core) is pulled across the air-gap and contacts the drum face. At this point, the armature core becomes more closely coupled to the magnetic circuit and the inductance of the coil increases significantly.
This invention relies on the characteristic of a solenoid type of clutch actuator that the inductance of a solenoid increases as the core is drawn into the magnetic circuit of the solenoid. Since the core is mechanically connected to the clutch, movement of the core is directly related to the position and therefore the state of the clutch and by taking advantage of this, the present invention permits the position of the clutch to be determined from the increase in the inductance of the coil that occurs as the core is drawn into the magnetic circuit.
Because the current flowing through a coil will tend to increase with time, according to a well-known relationship, the actual current through a coil as a function of time can be predicted relatively accurately. Where the inductance of the coil increases quickly enough as the core moves into the magnetic circuit, the current through the coil will decrease rather than increase as a function of time, and by monitoring the current through the coil and recognizing this decrease in current as the clutch begins to engage, the present invention provides a method and apparatus for controlling the engagement of the clutch to provide a soft start.
If the clutch armature (clutch disc) pulls in squarely toward the electromagnet a distinct drop in current will occur that is easy to detect. However, the current signature may be less distinct if the armature pulls in obliquely or if the armature assembly is vibrating.
Mechanical vibration of the armature can cause a variation of the inductance as the core position in the coil varies at the vibration frequency. This change in inductance will cause a resulting modulation of the current waveform at the vibration frequency. This effect is most pronounced just before the pull-in point as the electromagnet begins to pull the armature closer. This makes pull-in difficult to detect.
The armature may also pull in obliquely especially in the case where a permanent magnet brake is employed. In this case, the edge of the armature opposite the brake magnet typically pulls in first, causing a relatively small change in inductance. The disc may then peel or roll off the permanent magnet causing several more small changes in inductance rather than one large distinct change.
It is desirable to provide a clutch controller that automatically adjusts for different clutch models. Clutches come in many different sizes, larger clutches requiring more current to activate the solenoid than smaller clutches. In prior art controllers, predetermined absolute current set points have been used to control the operation of the clutches. For example, a controller might initiate a ramp at a starting point of 1.2 amps for a three amp clutch, and a starting point of 2 amps for a 5 amp clutch.
Another problem of known controllers is that the current ramp increases the current slowly from a preset value to 100%. In practice, the clutch is fully engaged at a value somewhat less than 100% and continuing the ramp past this value may cause clutch slippage and overheating.
Heretofore, while a speed sensor has been employed to select a predefined current profile, it is preferable to use the actual RPM of the motor as feedback to actively control the current during the ramp up. Doing this allows the input shaft RPM and the output shaft RPM to be used to actively control the slip via the clutch current.
However, the necessary RPM information is typically not available at reasonable cost on motors of the type to which this invention is addressed. This is particularly true with respect to the RPM of the output shaft. Consequently, known prior art controllers have been open loop controllers. That is, the clutch current is modulated with the expectation that the desired engagement profile will result. However, changing load conditions and clutch wear can cause the engagement profile to vary greatly from the desired profile.
Typically, what is most important to the application is that the load is accelerated smoothly and that mechanical stresses and noise are minimized.
While a variety of methods for controlling the current passing through the clutch may suggest themselves to those skilled in the art, and in accordance with the invention, it is preferred to control the current through the use of a pulse width modulator which can be adjusted to provide a controlled amount of current to the coil of the clutch and thereby to accomplish a soft start.
BRIEF SUMMARY OF THE INVENTION
In accordance with a presently preferred embodiment of the invention, current through the coil of a clutch actuator is initially sent to a high value by establishing a high duty or continuous cycle for a pulse width modulated current controller. When a decrease in current through the clutch is sensed, thereby indicating that engagement of the clutch has begun, the duty cycle of the pulse width modulator is reduced quickly to a lower value and thereafter increased in a controlled fashion to accomplish a soft start.
In accordance with an embodiment of this invention that automatically adapts to clutches of different sizes and current ratings, a normalization factor is used to scale the raw current measured by a current sensor such as an A/D converter by a normalization factor so that the clutch current varies by a scaled value between zero and 100% without regard to the actual maximum clutch current. The clutch current used by the controller to set the ramp current and to detect pull-in is described by the following equation:
ClutchCurrent=CurrentNormalizationFactor*Raw A/D where Raw A/D is the unscaled, current measured through the solenoid.
The invention contemplates determining the CurrentNormalizationFactor in several different ways. In accordance with one aspect of the invention the CurrentNormalizationFactor is based on RawA/D current measured at time t after the clutch is energized.
In accordance with another embodiment of this invention the CurrentNormalizationFactor is based on RawA/D current measured after the clutch solenoid has reached saturation. Because saturation occurs after the soft start has already occurred, the value is stored in nonvolatile memory for the next soft start.
In accordance with another aspect of this invention, pull-in detection is improved. While defining pull-in as a predefined drop in current below a stored maximum reference current detects pull-in in many instances, the present invention improves detection in those cases where pull-in is not distinct. In accordance with the invention the coil current waveform is sampled for example at 1 ms intervals and the rate of change of current over a predetermined time is calculated. This approximates the derivative of the coil current waveform over time (di/dt) and pull-in is defined to occur when di/dt falls below a Pull-InThreshold. By combining this technique with the detection of a sharp pull-in signature, the onset of pull-in may be reliably determined.
In accordance with another aspect of this invention, a clutch controller is provided having an adaptive pull-in detection threshold. Because the current through a solenoid necessary to pull in a clutch increases with clutch wear, a fixed Pull-in Threshold is not an accurate way to detect actual pull-in. In accordance with this invention, the rate of change of solenoid current with respect to time is compared to a calculated current wave form and the Pull-in Threshold is adjusted to accurately detect pull-in at different magnitudes of clutch current so as to adapt to clutch wear.
In accordance with another aspect of this invention, engine RPM is used to actively control the current supplied to the clutch solenoid. Where the clutch controller is used on a spark ignited internal combustion engine, the ignition pulse period can be used to derive engine RPM. RPM droop provides a simple approximation of the load on the driving motor and is therefore particularly useful in adjusting the clutch engagement profile.
In accordance with another aspect of the invention, the BaseRamp that can be initially defined as derived solely as a percentage of the normal current range is modified over time based on accumulated data from prior clutch engagements. In accordance with one aspect of the invention, the difference between the calculated BaseRamp and the actual BaseRamp at the start and end of the ramp are integrated with previous engagement errors at these points and applied to the BaseRamp starting and ending values, thereby adjusting the BaseRamp slope and offset for the next clutch engagement.
In accordance with another aspect of the invention, if desired, once the clutch is fully engaged, the current through the coil may be reduced to a holding value that is somewhat less than the current required to actuate the clutch, by adjusting the duty cycle of the pulse width modulated control power to a holding value. This feature reduces solenoid coil heat dissipation, thereby enabling the use of a higher power solenoid than would be possible without this adjustment.
In accordance with a further aspect of this invention the condition of a partial pull-in is accommodated by allowing the current to build beyond the detected pull-in point. When the current through the solenoid exhibits a large sharp drop, this indicates that complete pull-in has occurred and little or no additional current build time is needed or desired. When the change in current at pull-in is indistinct, an adaptive Pull-in Threshold (ApiInsuranceThr) is calculated based on the difference between the maximum pull-in current and the minimum current drop after pull-in is detected.
While the novel aspects of the invention are set forth with particularity in the appended claims, the invention itself together with further objects and advantages thereof may be more readily comprehended by reference to the following detailed description thereof taken in conjunction with the accompanying drawing in which:
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
FIG. 1 is a diagrammatic view of an arrangement for actuating an electric clutch utilizing the soft start clutch controller of this invention;
FIGS. 2A and 2B are diagrammatic views of the idealized engagement of a clutch of the type to which the invention relates;
FIGS. 3A through 3C are diagrammatic views of the typical engagement of a clutch of the type to which this invention relates;
FIG. 4 is a graphical representation of the current flowing through a clutch solenoid in accordance with one aspect of this invention;
FIG. 5 is a graphical representation of the current through a solenoid in accordance with another aspect of this invention;
FIG. 6 is a graphical representation of current normalization using the saturation value as a reference.
FIGS. 7 , 8 , and 9 are graphical examples of adaptive pull-in insurance;
FIG. 10 is a graph of prior art pull-in detection failing to detect an indistinct pull-in signature;
FIG. 11 is a graph of the derivative based pull-in detection method showing one sample before pull-in is detected on a distinct pull-in signature;
FIG. 12 is a graph of the derivative based pull-in detection method showing the sample where pull-in is detected on a distinct pull-in signature;
FIG. 13 is a graph of the derivative based pull-in detection method showing one sample before pull-in is detected on an indistinct pull-in signature;
FIG. 14 is a graph of the derivative based pull-in detection method showing the sample where pull-in is detected on an indistinct pull-in signature;
FIGS. 15 , 16 , and 17 are graphical representations of clutch current versus time showing adaptive pull-in detector threshold in accordance with this invention;
FIG. 18 is a graphical diagram of how the fixed pull-in threshold is determined;
FIG. 19 is a graph of input shaft RPM and current with respect to time for a clutch controller employing active load feedback in accordance with the invention;
FIG. 20 is a flow chart describing period normalization;
FIG. 21 is an example of period normalization;
FIG. 22 is a block diagram of the controller structure for RPM feedback;
FIGS. 23-26 are graphical representations of actual performance of a clutch controller in accordance with the invention;
FIG. 27 is a graph of input shaft load and current with respect to time for a clutch controller employing active load feedback in accordance with the invention;
FIG. 28 is a block diagram of the clutch control system of this invention with load feedback after pull-in is detected;
FIG. 29 is a block diagram of a load feedback arrangement in accordance with this invention with long term BaseRamp;
FIG. 30 is a block diagram of the controller structure for long term base correction for load;
FIG. 31 is a software block diagram of a softstart algorithm for the clutch controller shown in FIG. 6 ;
FIG. 32 is a software block diagram of a current control PWM algorithm for the clutch controller of FIG. 6 . FIG. 33 is a schematic diagram of a clutch controller in accordance with this invention; and
FIG. 33 is a schematic diagram of a controller in accordance with the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagrammatic view of a clutch arrangement utilizing a clutch controller in accordance with this invention. A clutch 10 includes an input connector 12 for connecting clutch 10 to soft start clutch controller 18 by way of first and second electrical conductors 14 and 16 . Conductors 14 and 16 are connected to output terminals 20 and 22 of clutch controller 18 . Clutch controller 18 also includes input terminals 24 and 26 . Input terminal 26 is conventionally connected to ground while input terminal 24 is connected to a source of 12 volt DC power such as a battery 30 by way of a power switch 28 . When power switch 28 is closed, clutch controller 18 applies power to clutch 10 by way of connector 12 as will be described in more detail below. Input 302 is connected to a an insulated wire that is wrapped around the insulation of a high tension spark plug wire, for example 3 to 4 turns, to capacitively couple pulses from the spark plug wire to the input.
FIGS. 2 and 3 are diagrammatic illustrations showing clutch engagement under ideal and typical circumstances. As shown in FIGS. 2( a ) and 3 ( a ), when disengaged, the clutch driven side and the clutch output side are spaced apart so that no power is transferred between them and moreover the outside clutch plate is ideally disposed parallel to the driven side clutch plate. As the clutch is drawn in, in an ideal clutch, the output side clutch plate remains parallel to the driven side clutch plate as shown in FIG. 2( b ) and engages substantially simultaneously over the entire surface.
In practice, as shown in FIG. 3 , while it is often possible to maintain the driven side and output side clutch plates essentially parallel when the clutch is disengaged, when the clutch is engaged, the output side clutch plate may contact the driven side clutch plate obliquely as shown in FIG. 3( b ) and subsequently move into the position shown in FIG. 3( c ). As shown in FIGS. 3( b ) and 3 ( c ), some clutch manufactures use a permanent magnet brake on the back side of the clutch plate which further exaggerates this problem. This invention allows for this common effect.
FIGS. 4 and 5 are graphical representations of the current applied to a clutch solenoid in accordance with first and second basic open loop embodiments of the invention. Referring to FIG. 4 , the current is shown on a vertical axis against time shown on the horizontal axis. When the clutch is engaged, for example when switch 28 as shown in FIG. 1 is closed, the current begins to increase with time at a rate determined primarily by the inductance of the clutch solenoid. As the current increases, the clutch controller monitors the current and elapsed time, calculating the CurrentNormalizationFactor at time t.
Referring to FIG. 4 , a graph of current versus time is shown to illustrate the manner in which a controller in accordance with this invention adapts to clutches of various sizes and current ratings. Normalization of the current is used to automatically scale the raw A/D value to ClutchCurrent so that ClutchCurrent is targeted to reach approximately 100% at clutch coil saturation.
After current is applied to a clutch, the current flowing through the clutch is measured after a pre-determined time t and stored as Raw Reference A/D. Raw Reference A/D is used to calculate a normalization factor according to the equation:
CurrentNormalizationFactor=Target/Raw Reference A/D
Normalization Factor is then used to scale Clutch Current as follows:
ClutchCurrent=CurrentNormalizationFactor*Raw A/D
The target is a predetermined value, chosen to provide a normalized 100% maximum value of ClutchCurrent for any sized clutch. ClutchCurrent is then used for all clutch control functions. In this example, Target is approximately 20%.
An alternate normalization method is calculated from the saturation current which has been previously measured after the clutch has reached saturation as shown in FIG. 6 . This occurs after the soft start portion of the clutch actuation has occurred and the saturation value is stored in non-volatile memory for the next soft start. In this example, Target is 100%.
Nv Normalization Factor=Target/RawReference A/D
Referring again to FIG. 4 , ClutchCurrent continues to build after time t until the controller detects a local maximum where the current begins to decrease. Normally, this maximum occurs just as contact is first made between the driven side and the output side of the clutch which increases the inductance of the coil and reduces the current. When the current through the clutch solenoid decreases to 95% of the MaxPull-in Current, the start of clutch engagement is declared and CurrentSetpoint is set to the Ramp begin value of 20% of the normalized current range.
When the measured ClutchCurrent has decreased to CurrentSetpoint at Ramp begin value, current is again supplied to the clutch solenoid but at a controlled ramp rate to facilitate a smooth engagement of the clutch. Preferably, the controlled rate is a linear ramp but other controlled increases in current are also contemplated as described below. When the end of the ramp is reached, the clutch should be fully engaged. CurrentSetpoint is set to 100% to ensure full engagement and current is applied to the coil at a rate limited only by the coil inductance.
FIG. 5 shows a graph of the current through a clutch solenoid vs. time in accordance with another embodiment of the invention having an additional feature adapted for uneven engagement of the clutch plates as shown in FIG. 3 . The wave form of FIG. 5 compensates for partial pull-in which would otherwise be detected as full pull-in, causing the current through the clutch solenoid to be reduced and the clutch to either disengage or, drag along the output disc edge until the ramp current increases to a point where the clutch disc pulls in fully, resulting in a delayed and abrupt engagement.
As shown in FIG. 5 , when the maximum current is detected, a set point is established at 95% of the maximum current to detect the beginning of clutch engagement as shown in FIG. 4 . When the current falls below 95% of the maximum current, the maximum current is saved as “MaxPull-in Current”, a new current set point is established at 1.2 times the MaxPull-in Current and power is continuously applied to the clutch until the new current set point is reached whereupon power to the clutch solenoid is removed and the current begins to decrease with time at a rate again determined primarily by the inductance of the solenoid to a point equal to 20% of the normalized current range. At this point, the current ramp up proceeds as already described in connection with FIG. 4 .
This second embodiment allows for the initial reduction of current caused by the sort of uneven initial contact illustrated in FIG. 3( b ) by continuing to apply current until a higher threshold is reached thereby providing “pull-in insurance” that actual clutch contact has occurred.
Because of mechanical variations during operation varying degrees of pull-in may occur. Allowing the current to build to 1.2 times MaxPull-in Current after a complete pull-in is unnecessary and may cause a harsh engagement.
When a sharp drop in current occurs, complete pull-in is indicated and little or no additional current build time is needed or desired. A less distinct drop indicates a partial pull-in which requires current to build to a higher level.
To account for variations in pull-in, as shown in FIGS. 7 and 8 , an adaptive pull-in insurance threshold (ApiInsuranceThr) replaces the fixed threshold of 1.2 times MaxPull-in Current previously described. ApiInsuranceThr varies based on the difference between the MaxPull-InCurrent and the MinPull-InCurrent recorded after pull-in is detected according to the following formula:
ApiInsuranceThr=MaxPull−InCurrent×PiBuildFactor−PiQualFactor×(MaxPull−InCurrent−MinPull−InCurrent)
To account for changes in MinPull-InCurrent, ApiInsuranceThr is continually recalculated and compared to ClutchCurrent (the measured current). Once ClutchCurrent exceeds ApiInsuranceThr, normal ramping commences.
PiBuildFactor and PiQualFactor are constants. Typical values are:
PiBuildFactor=1.5
PiQualFactor=2
As the clutch nears the end of its life, the current may not reach ApiInsuranceThr before coil saturation is reached. To ensure that the softstart occurs within a reasonable timeframe, a timeout is added according to the following rule:
Allow current to build until current is greater than or equal to ApiInsuranceThr or timeout occurs.
As shown in FIG. 7 , for a relatively new clutch with little vibration, the onset of pull-in is distinct and easily recognized. Because of the large difference between MaxPull-InCurrent and Min Pull-in Current, ApiInsuranceThr is set relatively low and ramping begins relatively quickly after the onset of pull-in is detected.
As shown in FIG. 8 , when pull-in is less distinct, ApiInsuranceThr is greater, thus allowing more time for current to build before ramping begins.
This allows current to build beyond MaxPull-InCurrent to be certain that pull-in has actually occurred.
As shown in FIG. 9 , the combination of extra pull-in time and pull-in insurance timeout due to coil saturation are shown. The pull-in signature is relatively indistinct as in the example shown in FIG. 28 , and moreover, coil saturation occurs before the current reaches ApiInsuranceThr. Accordingly, after PI timeout, the ramp phase is initiated automatically.
While the embodiments of the invention described above provide adequate performance in many situations, especially where a distinct drop in current occurs when the clutch armature (clutch disc) pulls in to contact the electromagnet, this distinct current signature, as shown in FIG. 4 , occurs reliably only when the armature pulls in squarely towards the electromagnet in one quick fluid motion. In many practical applications, the current signature may be less distinct if the armature pulls in obliquely or if the armature assembly is vibrating as shown in FIG. 10 . Vibration of the armature can cause a variation of the inductance as the armature distance varies at the vibration frequency. The change in inductance will cause a resulting modulation of the current waveform. The effect is most pronounced just before the pull-in point as the electromagnet begins to pull the armature closer. Vibration and oblique pull-in may occur together especially in a case where a permanent magnet brake is employed. In this case the edge of the armature opposite the brake magnet typically pulls in first causing a relatively small change in inductance and consequently a small change in current. The disk may then peel off the permanent magnet causing several more small changes in inductance rather than one large distinct change. The Pull-in Threshold may be reduced below 5% to compensate for this but this is generally undesirable because it increases the likelihood of false or premature triggers due to noise or armature vibration alone. As can be seen, the current does not fall below the magnitude required to indicate a pull-in, and consequently, after the clutch is actually pulled in, the current continues to increase uncontrolled to saturation.
FIG. 10 is a graph of current versus time showing these effects. The current increases relatively smoothly from the origin initial current 100 to a first current maximum indicated at 102 . Subsequently, as the clutch begins to pull in, clutch vibration causes a series of local minima and maxima 104 of current to occur none of which causes the current to fall below the preselected threshold such as 5% of the maximum current. Consequently, the current is not reduced sufficiently for detection in accordance with the method described above and following the undetected partial pull-in, the current continues to increase to a maximum commencing at time 106 .
In accordance with another aspect of this invention, a plurality of current samples is taken but instead of merely storing the highest current value and presuming clutch pull-in when the current falls below that value by a predetermined percentage such as 5%, the rate of change of current with respect to time (di/dt) is calculated from the sample current values. When di/dt falls below the Pull-in Threshold, pull-in is detected and the controller takes over control of the current to begin the soft start ramp period. While the examples described herein use 7 one millisecond samples, both the duration of the samples and the number of samples may vary somewhat. The length of the samples and the number of samples evaluated to determine di/dt are preferably selected to provide a reliable indication of pull-in without overloading the microprocessor that makes the calculations.
FIGS. 11-13 show examples of this technique where Pull-in Threshold is set to one. As shown in FIG. 11 , the current is sampled every 1 ms and the magnitude of the current detected during each sample is used to compute a derivative of the current with respect to time over a predetermined number of samples, for example 5 to 20, in this case seven. In the example shown in FIG. 11 the derivative is 6.9 which is above Pull-in Threshold resulting in no pull-in having occurred over this interval.
FIG. 12 shows the same graph as FIG. 11 at the point where pull-in is detected. The one millisecond samples are summed over a subsequent seven millisecond period, but in this case, in the last sample of the new period, the current drops by five and the derivative is plus 0.3. Since this is less than the Pull-in Threshold of 1, pull-in is detected.
FIGS. 13 and 14 show the application of the derivative pull-in detection method to a clutch where a sharp pull-in signature is not present. The figures show the current with respect to time which is the same in each of the two figures. In FIG. 13 , the 7 one millisecond samples are summed to produce the derivative di/dt. In this case, the sum is 2.0. With a Pull-in Threshold of 1, pull-in is not detected at this time.
FIG. 14 shows the same window, but one sample later. The derivative di/dt is now 0.6 and with a Pull-in Threshold of 1, pull-in is detected. This demonstrates that the derivative method can be used to detect pull-in in situations such as the one shown in FIG. 10 where the previously described method would not detect pull-in.
As already discussed, pull-in is detected by continuously monitoring the clutch current and noting the characteristic decrease in current when pull-in occurs. A threshold is established to avoid false sensing due to irregularities not indicative of clutch pull-in. A problem with known clutch controllers is that a fixed Pull-in Threshold does not account for clutch wear and may result in the failure to detect pull-in of a worn clutch.
FIG. 15 is a graph of current versus time for a new clutch showing early pull-in. FIG. 17 is a graph of current versus time for a worn clutch showing late pull-in. As can be seen, the rate of change of current with respect to time at pull-in for a new clutch is much higher than the rate of change of current with respect to time for a worn clutch. A single Pull-in Threshold cannot accurately detect pull-in in both of these situations.
In accordance with this invention, the Pull-in Threshold must be changed as the point on the current versus time graph at which pull-in occurs changes.
In accordance with this invention, as shown in FIG. 16 , a synthesized current waveform is generated to approximate the actual current through a clutch coil inductor over time. The synthesized current does not simulate the reduction in current produced by pull-in, so that it is essentially a calculated curve based upon the inductance the solenoid, the applied voltage, and other factors. The synthesized current waveform can be stored as an equation or a look-up table for faster response. The synthesized current waveform is adjusted to be at the same scale as the clutch current so that at saturation, the synthesized current equals the clutch current.
In accordance with the invention, as shown in FIG. 18 , a fixed threshold is set to one half the expected drop in current produced by a typical pull-in. That is, if the drop in current during pull-in is expected to be 4, the fixed threshold is set to 2. The Pull-in Threshold is then set equal to the synthesized change in current minus the fixed threshold. The synthesized change in current is the change in current versus time for a predetermined time period, in this example 15 milliseconds. Referring to FIG. 15 , it can be seen that for a new clutch, pull-in occurs at a relatively low current, whereas, as shown in FIG. 17 , for a worn clutch, pull-in occurs at a higher current. The synthesized change in current at the low current pull-in point is 10, while the synthesized change in current at the high current pull-in point is 2. The value for the fixed threshold is set to 2, one-half the expected drop of 4. Applying these numbers to the formula, for a new clutch the change over 15 milliseconds immediately preceding the time of pull-in is 10. Subtracting 2 yields 8. For a worn clutch, the change in current over 15 milliseconds just prior to the time of pull-in is 2, and the Pull-in Threshold is therefore 0.
Up to this point all of the elements of the basic softstart controller operating in an open loop mode have been described. In accordance with another aspect of this invention, the invention relates to a method of controlling the solenoid current during the period at which the current is supplied to the solenoid at a controlled rate. Referring to FIG. 19 , the initiation of a pull-in is detected in one of the ways already described, that is by noting a drop in the absolute current flowing through the solenoid or by comparing the rate of change of the current to a pre-determined value. Once the commencement of a pull-in has been detected, the current to the solenoid is reduced to begin commencement of the controlled engagement ramp period. Subsequently, BaseRamp current is increased during the controlled engagement period. Simultaneously, the ActualRPM of the input shaft is compared to a DesiredRPM profile and an Error signal is generated. The Error equals the ActualRPM minus the DesiredRPM times the configuration gain, an amount determined in advance. The current is adjusted by adding the Error determined from the ActualRPM to the base current. In this way, by adjusting the current, the error between the ActualRPM and the DesiredRPM is minimized.
Once the actual current has increased to a pre-selected level, complete clutch engagement is presumed and the current is thereafter permitted to increase at a rate limited by the coil inductance as has already been discussed.
RPM droop is an approximation of engine load and as such the DesiredRPM profile may be selected to provide a number of different levels of soft engagement. One method is to decrease the RPM linearly from about 95% of the ReferenceRPM at the beginning of clutch engagement to about 60% of the ReferenceRPM at full engagement. Note that the 95% RPM beginning point is chosen to account for the approximate initial RPM drop that occurs while the clutch coil current is decaying during the period between when pull-in occurs and when the ramp up begins.
A method for controlling clutch engagement in accordance with this invention may be summarized as follows. All references are to FIG. 19 .
Immediately after power up, CurrentSetpoint is set to 100% duty cycle to apply maximum DC power to the armature coil.
At time t CurrentNormalizationFactor is calculated as described previously.
Immediately before engagement commencement, the ReferenceRPM is captured. Preferably, the RPM is captured right before pull-in is detected.
While it is possible to measure RPM directly, it may be more convenient to measure the period of a signal related to RPM such as the period between spark pulses. This period can be used directly or converted to RPM according to the formula
RPM=60/period.
Where period is the time in seconds between pulses.
In accordance with one aspect of the invention the ReferenceRPM or reference period is normalized to a constant at the time of measurement. This has two advantages. Without normalization, the loop gain of the control loop will vary as the RPM changes. For example, a 10% error at 2000 RPM is 200 RPM while a 10% error at 4000 RPM is 400 RPM. Normalization makes these two the same. Normalization also permits the software to operate independently of system configuration differences such as the number of spark pulses per revolution or the actual engine speed. This allows the controller to be used for example on two and four cycle engines as well as on engines operating at different normal speeds, without modification. FIG. 20 is a block diagram of an exemplary method for determining the normalized period from a measured period and a predetermined reference period.
Normalization has a second advantage. The period is often measured as a 16-bit number. When an 8-bit microprocessor is used to keep costs low, processing 16 bit numbers is computationally inefficient. By normalizing the period, the 16-bit number may be converted to an 8-bit number without substantially affecting the dynamic range of the measurement.
FIG. 21 provides an example of period normalization. Immediately after beginning, pull-in is tested. If pull-in has not occurred, the process loops back until pull-in is detected. Once pull-in is detected, the reference period is set to a stored value, in this case 20,000 us and the normalization factor is set equal to 20,000 divided by 100, yielding a normalization factor of 200 in this case. The normalized period is then continuously recalculated until the ramp has been completed and the routine exits.
Pull-in is then detected using either the derivative method or the fixed current drop method described above.
Once the initiation of pull-in has been detected, the BaseRamp current profile is generated as described previously. The BaseRamp profile is typically chosen for optimum open loop soft start performance. Simultaneously, the DesiredRPM profile is generated.
DesiredRPM profile is the desired engine droop rate for a normal engagement based on a percentage of the ReferenceRPM. This profile may be linear or non-linear over time and is based on a percentage of the ReferenceRPM captured in Step 3.
In the example shown in FIG. 19 , the start of the DesiredRPM Profile is 95% of the ReferenceRPM, and the end of the DesiredRPM Profile is 60% of the ReferenceRPM.
The ActualRPM is then continuously compared to the DesiredRPM profile and an error signal is generated. The error is the difference between the ActualRPM and the DesiredRPM. The error is scaled by the configuration gain constant selected for optimum loop stability.
Error is the difference between the DesiredRPM Profile and the ActualRPM at any given time scaled by the ConfigGain. AdjustedRamp is the BaseRamp plus the error, and therefore is the actual CurrentSetpoint that is applied to the clutch coil.
Adding Error to BaseRamp will vary the coupling of the load to the engine with the goal of fitting engine RPM as closely as possible to the DesiredRPM profile.
For clarity of explanation, the method just described used a simple proportional controller. FIG. 22 shows a block diagram of the controller for this embodiment. In FIG. 22 the Error term is fed into a ControlSystem block where it is conditioned before being added to BaseRamp. There are many different control system topologies that will prove effective, but a PID controller will provide good results.
The efficacy of the soft start clutch and the method described herein may be more readily appreciated by a reference to the results of tests made on the clutch, which results are shown in FIGS. 23 and 24 . FIG. 23 shows the results of a first test in which the ramp current was set for a very soft engagement with the ramp starting at 80 and ending at 110. No feedback was employed.
The engine RPM is shown by trace 400 and the output shaft RPM is shown by trace 410 . As can be seen, although the output shaft RPM increases gradually, the engine shaft RPM shows a significant dip at the end of the ramp, illustrating excessive slippage throughout the ramping period.
In FIG. 24 , feedback in accordance with this invention is employed and the output shaft RPM shown by trace 420 increases smoothly while there is a significantly reduced dip in the engine shaft RPM 440 , thus indicating a soft engagement.
The results of a second test are illustrated at FIGS. 25 and 20 . In this case, the ramp was set for a harsh engagement, the ramp starting at 150 and ending at 200. In FIG. 19 , no feedback is employed and a very sharp dip in engine shaft RPM is observed at the time of clutch engagement. In FIG. 26 , with feedback in accordance with this invention, the dip in engine shaft RPM is significantly reduced, thus indicating a soft start in accordance with the invention.
In the previous example RPM droop was used as a simple approximation of engine load. More direct measurements of load can of course be used. For example, the current and voltage supplied to an electric motor may be measured as ActualLoad and applied to the control system shown in FIG. 28 .
FIG. 27 graphically illustrates a general example of load feedback.
Immediately after power up, CurrentSetpoint is set to 100% duty cycle to apply maximum DC power to the armature coil.
At time t CurrentNormalizationFactor is calculated as described previously.
Pull-in is then detected using either the derivative method or the current draw method described above.
Once the initiation of pull-in has been detected, the BaseRamp current profile is generated as described previously. Simultaneously, the DesiredLoad profile is generated.
The DesiredLoad profile is the desired motor load rate for a normal engagement based either on predetermined values or as a percentage of ReferenceLoad which had been captured and stored from previous soft starts. This profile may be linear or non-linear over time.
In the example shown in FIG. 19 , the start of the DesiredRPM Profile is offset above zero to account for initial uncontrolled loading that occurs when the solenoid current is decaying between the time that pull-in occurs and the time that the ramp begins.
Error is the difference between the DesiredLoad Profile and the ActualLoad at any given time scaled by the ConfigGain. AdjustedRamp is the BaseRamp plus the error, and therefore is the actual CurrentSetpoint that is applied to the clutch coil.
For clarity of explanation, the method just described used a simple proportional controller. FIG. 28 shows a block diagram of the controller for this embodiment.
Referring now to FIG. 29 , an arrangement similar to FIG. 28 is illustrated with long term feedback added. The elements of FIG. 29 that are the same as in FIG. 28 are identified with the same reference numbers. As can be seen, the error at the beginning and ending of the ramp is sampled by closing switches 61 , 63 , and 65 and integrating the error over time. Any number of multiple switches and integrators may be added as represented by the dotted line example at t=x. The integrated error is then applied to the BaseRamp for subsequent starts so that the error is minimized. BaseRamp is used as described previously, in FIGS. 28 and 30 .
FIG. 30 shows a controller example which uses long term feedback exclusively. It is essentially the same as the controller described in FIG. 29 with real time feedback removed. As can be seen, the error at the beginning and ending of the ramp is sampled by closing switches 61 , 63 , and 65 and integrating the error over time. Any number of multiple switches and integrators may be added as represented by the dotted line example at t=x. The integrated error is then applied to the BaseRamp for subsequent starts so that the error is minimized.
In accordance with another embodiment, the current normalization may be eliminated altogether and replaced by a conventional factory calibration of the ClutchCurrent.
FIG. 31 is a flowchart showing how the basic software in microcontroller 160 operates to implement the invention. On boot up, either upon the initial application of power or upon the system being reset, an initialization routine as shown at 40 is performed. The current set point is set to zero while a delay period at 42 elapses to wait for the system to stabilize.
The CurrentSetpoint is initialized to 100% at 44 , and clutch coil current begins to build limited only by its L/R time constant. At time t shown by 46 , the software captures a RawA/D sample to be used in the CurrentNormalizationFactor calculation at 48 .
At 50 , the controller software loops at a 1 ms rate while repeatedly calculating Derivative and updating SynthesizedCurrent. Derivative is then compared it to the Pull-in Threshold which is derived from SynthesizedCurrent.
At 52 , immediately after pull-in is detected ReferencePeriod is captured where it is used in the PeriodNormalizationFactor calculation at 53 .
ClutchCurrent continues to build while it is compared against ApiInsuranceThreshold in 54 .
When ClutchCurrent exceeds ApiInsuranceThreshold at 56 , the first BaseCurrent point is generated. At essentially the same time the first DesiredRPM point is generated at 58 . At 60 Error is calculated by Subtracting DesiredRPM from ActualRPM. A new CurrentSetpoint is produced at 61 . If End of Ramp has not occurred at 62 , the process is repeated where the next ramp points are generated and a new Error calculation is made.
At 63 CurrentSetpoint is set to 100% to ensure that the clutch is fully engaged.
FIG. 32 is a software block diagram showing the manner in which the controller shown in FIG. 6 controls the current through the clutch solenoid. The current is sampled by measuring a voltage across resistor 132 at a rate of 50 kHz. The analog to digital conversion occurs within controller 160 . The current is averaged every 50 samples, that is approximately 1,000 times per second, in block 66 and the average current is compared to the CurrentSetpoint minus hysteresis in block 68 . If the current is below the CurrentSetpoint FET 123 is turned on in block 70 and the saturation detector 220 is tested in block 72 . If the current is higher than the saturation current and the over current timeout has expired as tested at block 74 then the FET is latched off in block 76 . As long as the saturation current is not exceeded or is exceeded only for a short time the routine terminates in block 78 .
Returning to block 68 , if the current is greater than the CurrentSetpoint minus hysteresis and continues to increase until it is greater than the CurrentSetpoint as tested in block 80 , the FET is turned off in block 82 , the over current timeout is reset in block 84 and the routine terminates in block 78 . If the current is not greater than the CurrentSetpoint as tested in block 80 then the routine terminates at block 78 .
FIG. 33 is a schematic diagram of a clutch controller in accordance with another embodiment of the invention. A power source such as a 12 V DC power source is connected to an input terminal 102 . Terminal 102 is connected by way of a diode 104 to an input terminal 106 of a voltage regulator 108 . Regulator 108 has a ground terminal 110 and an output terminal 112 that provides an operating voltage for example 4.7 V to the other elements of the clutch controller as will be discussed in more detail below. A filter capacitor 114 filters the output of voltage regulator 108 and the filtered output is available on terminal 116 .
Input terminal 102 is also connected to the source terminal 120 of field effect transistor 122 . Drain 124 of FET 122 is connected to a first clutch solenoid terminal 126 . The other end of the clutch solenoid is connected to terminal 128 which is connected to ground through low resistance resistor 132 which may have resistance of approximately 0.1 ohm. Resistor 132 is connected in such a way that both the ON and OFF current through the clutch solenoid may be measured by sensing the voltage drop across resistor 132 . Ground is connected to output terminal 130 . A snubber diode 134 is connected between terminal 126 and ground to provide a path for the clutch solenoid recirculating current during the PWM off period.
Gate electrode 136 of FET 124 is clamped to a maximum gate-source voltage of approximately 10V by zener diode 138 . Gate terminal 136 is connected to the collector of gate drive transistor 140 by current limiting resistor 142 which may have a value of approximately 390 ohms. A zener diode, preferably a 20 V zener diode 144 is connected between the collector and the emitter of transistor 140 to limit the voltage applied to transistor 140 during a “load-dump” transient. Load-dump transients can occur when the 12V battery is suddenly disconnected from a running engine's charging system. Zener diode 144 also forces FET 122 ON during the load dump, both to keep FET 122 's drain-source voltage within safe limits and to help to suppress the load-dump by providing a load via the clutch. Collector 146 of transistor 140 is connected to the 12 volt source through resistor 148 which is preferably a 1.5 K. ohm resistor. Base 150 of transistor 140 is connected to an output of microcontroller 160 by a series resistor 162 . Base resistor 164 is connected between the base 150 and ground and preferably has a value of approximately 2 K. ohms
The current through the clutch solenoid coil is sensed as a voltage drop across resistor 132 which is connected through a filter comprising a series resistor 170 and a capacitor 173 to a non-inverting input 172 of a comparator 174 . Preferably, resistor 170 has a value of approximately 2 K. ohms. An inverting input 176 of comparator 174 is connected to ground through a series resistor 178 which preferably has a value of about 1000 ohms. A feedback resistor 180 is connected between output 182 of comparator 174 and inverting input 176 . The output of comparator 174 is connected to an input 190 of controller 160 through a filter comprising a series resistor 192 which preferably has a value of approximately 2 K. ohms and a capacitor 194 which preferably has a value of 0.01 μF.
The filtered current signal is also connected to the inverting input 198 of a comparator 200 whose non-inverting input 202 is connected to a voltage divider comprising a first resistor 204 which preferably has a value of approximately 20 K. ohms and a second resistor 206 which preferably has a value of approximately 10 K. ohms. A filter capacitor 208 is connected in parallel with resistor 206 . Comparator 200 provides a signal at output 210 when the current through the clutch solenoid exceeds a predetermined value set by the ratio of resistors 204 and 206 . The current overload signal is applied to input 212 of controller 160 which is preferably an interrupt input.
The clutch controller uses a high side driver with the FET 122 switching the voltage provided to the clutch at terminal 126 and senses the current in the return path at terminal 128 . In the case of an external short circuit to ground, the return path is bypassed. In this case the FET 122 could see a dangerously high current while the sense circuit measured zero current.
The FET drain-source saturation voltage is dependent on the current and the FET R DSON of 0.06 ohms. If the current is normal (<5 A), the FET will saturate to less than 0.3V across its drain-source. As the current increases the saturation voltage increases. Therefore, by monitoring the saturation voltage the approximate current through the FET can be sensed to provide short circuit protection.
A saturation detector comparator 220 has a non-inverting input 234 connected to a first voltage divider comprising resistors 222 and 224 connected between the FET drain terminal 124 and ground, and a second inverting input 235 connected to a second voltage divider comprising resistors to 226 and 228 connected between FET source terminal 120 and ground. Zener diodes 230 and 232 limit the voltage is produced by the two voltage dividers to safe values but do not otherwise affect the comparison. Preferably, resistor 222 has a value of approximately 75 K. ohms, resistor 224 has a value of approximately 10 K. ohms, resistor 226 has a value of approximately 100 K. ohms, and resistor 228 has a value of approximately 10 K. ohms.
Comparator 220 preferably has a feedback resistor 233 which may have a value of 1 meg. ohm connected between its noninverting input 234 and its output 236 to provide a degree of hysteresis for the saturation detector. Output 236 of saturation detector 220 is connected to an input 240 of microcontroller 160 .
Neglecting hysteresis resistor 232 , the resistor ratios are set up for a comparator transition with the FET source 120 at 12V and the drain 124 at 9.27V. Therefore, if the drain is above 9.27V the comparator output 220 is high, below 9.27 it is low. This gives a drain-source maximum of 2.73V—this threshold was set high to ensure that there would be no false trips. It could be reduced significantly to reduce maximum short circuit current.
A sensor 300 is coupled to the ignition circuit of the engine being controlled and to microprocessor 160 for measuring the RPM of the engine. As shown in FIG. 1 , input 302 is connected to a an insulated wire that is wrapped around the insulation of a high tension spark plug wire, for example 3 to 4 turns, to couple pulses from the spark plug wire to the input 302 of the sensor. Input 302 is capacitively coupled to the base 304 of transistor 306 . The negative going portion of the coupled spark signal turns on transistor 306 and produces a positive going edge at collector 308 which is coupled to the timer input 310 of microcomputer 160 . The microcomputer preferably includes an interrupt routine for measuring the period between positive edges of the pulses coupled to the microcomputer for determining the RPM of the engine.
While the invention has been described in connection with certain presently preferred embodiments thereof, those skilled in the art will recognize that many modifications and changes may be made therein without departing from the true spirit and scope of the invention which accordingly is intended to be defined solely by the appended claims. | A clutch actuator for an electromechanical clutch having a solenoid actuating coil initially provides power to the solenoid at a high rate by using a high duty cycle pulse with a modulated controller. When the initial engagement of the clutch elements is sensed by a decrease in current, the duty cycle of the pulse width modulator is reduced and thereafter increased in a controlled fashion to accomplish a soft start. | Identify the most important claim in the given context and summarize it | [
"CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser.",
"No. 11/741,475 filed Apr. 27, 2007.",
"STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT none REFERENCE TO A “SEQUENCE LISTING”",
"Not applicable.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention This invention relates generally to the actuation of electromagnetic clutches and more particularly to a controller for such clutches that reduces the stresses associated with engagement of the clutches by providing a progressive or soft start.",
"Description of Related Art Electromagnetic clutches are used in a variety of applications, including coupling large and small engines and motors to equipment operated by the engines or motors either directly or through transmissions.",
"Especially in the case of relatively small engines and motors, the price of clutch controllers is a significant factor in the implementation of such controllers.",
"However, small engine applications also benefit significantly from controlling the abrupt engagement of clutches since such engagement may increase wear, cause undesirable operating characteristics such as jerking, or cause the engine to stall if the clutch is engaged abruptly.",
"There have, in the past, been some efforts made towards reducing the abruptness of clutch engagement.",
"Such methods have taken various forms, including mechanical arrangements that suffer from the disadvantage that they are complex and expensive, and electrical arrangements such as a simple switch that have provided less than optimal results.",
"This invention provides a simple and inexpensive method for soft starting an electromagnetic clutch.",
"In almost all instances, an electromagnetic clutch includes a coil or solenoid through which a current is passed to actuate the clutch, an at least partially ferrous core is arranged to be drawn into the magnetic circuit when current is supplied to the coil.",
"The coil typically resides inside a metal drum directly connected to the engine output shaft.",
"The coil is stationary, but is magnetically coupled to the spinning drum.",
"The armature core usually consists of the clutch disk itself, which is mechanically connected to the output shaft of the clutch assembly and is separated from the driven side by an “air-gap.”",
"As current is applied to the coil, the magnetic field of the coil builds as the drum is magnetized to the point where the output disk (armature core) is pulled across the air-gap and contacts the drum face.",
"At this point, the armature core becomes more closely coupled to the magnetic circuit and the inductance of the coil increases significantly.",
"This invention relies on the characteristic of a solenoid type of clutch actuator that the inductance of a solenoid increases as the core is drawn into the magnetic circuit of the solenoid.",
"Since the core is mechanically connected to the clutch, movement of the core is directly related to the position and therefore the state of the clutch and by taking advantage of this, the present invention permits the position of the clutch to be determined from the increase in the inductance of the coil that occurs as the core is drawn into the magnetic circuit.",
"Because the current flowing through a coil will tend to increase with time, according to a well-known relationship, the actual current through a coil as a function of time can be predicted relatively accurately.",
"Where the inductance of the coil increases quickly enough as the core moves into the magnetic circuit, the current through the coil will decrease rather than increase as a function of time, and by monitoring the current through the coil and recognizing this decrease in current as the clutch begins to engage, the present invention provides a method and apparatus for controlling the engagement of the clutch to provide a soft start.",
"If the clutch armature (clutch disc) pulls in squarely toward the electromagnet a distinct drop in current will occur that is easy to detect.",
"However, the current signature may be less distinct if the armature pulls in obliquely or if the armature assembly is vibrating.",
"Mechanical vibration of the armature can cause a variation of the inductance as the core position in the coil varies at the vibration frequency.",
"This change in inductance will cause a resulting modulation of the current waveform at the vibration frequency.",
"This effect is most pronounced just before the pull-in point as the electromagnet begins to pull the armature closer.",
"This makes pull-in difficult to detect.",
"The armature may also pull in obliquely especially in the case where a permanent magnet brake is employed.",
"In this case, the edge of the armature opposite the brake magnet typically pulls in first, causing a relatively small change in inductance.",
"The disc may then peel or roll off the permanent magnet causing several more small changes in inductance rather than one large distinct change.",
"It is desirable to provide a clutch controller that automatically adjusts for different clutch models.",
"Clutches come in many different sizes, larger clutches requiring more current to activate the solenoid than smaller clutches.",
"In prior art controllers, predetermined absolute current set points have been used to control the operation of the clutches.",
"For example, a controller might initiate a ramp at a starting point of 1.2 amps for a three amp clutch, and a starting point of 2 amps for a 5 amp clutch.",
"Another problem of known controllers is that the current ramp increases the current slowly from a preset value to 100%.",
"In practice, the clutch is fully engaged at a value somewhat less than 100% and continuing the ramp past this value may cause clutch slippage and overheating.",
"Heretofore, while a speed sensor has been employed to select a predefined current profile, it is preferable to use the actual RPM of the motor as feedback to actively control the current during the ramp up.",
"Doing this allows the input shaft RPM and the output shaft RPM to be used to actively control the slip via the clutch current.",
"However, the necessary RPM information is typically not available at reasonable cost on motors of the type to which this invention is addressed.",
"This is particularly true with respect to the RPM of the output shaft.",
"Consequently, known prior art controllers have been open loop controllers.",
"That is, the clutch current is modulated with the expectation that the desired engagement profile will result.",
"However, changing load conditions and clutch wear can cause the engagement profile to vary greatly from the desired profile.",
"Typically, what is most important to the application is that the load is accelerated smoothly and that mechanical stresses and noise are minimized.",
"While a variety of methods for controlling the current passing through the clutch may suggest themselves to those skilled in the art, and in accordance with the invention, it is preferred to control the current through the use of a pulse width modulator which can be adjusted to provide a controlled amount of current to the coil of the clutch and thereby to accomplish a soft start.",
"BRIEF SUMMARY OF THE INVENTION In accordance with a presently preferred embodiment of the invention, current through the coil of a clutch actuator is initially sent to a high value by establishing a high duty or continuous cycle for a pulse width modulated current controller.",
"When a decrease in current through the clutch is sensed, thereby indicating that engagement of the clutch has begun, the duty cycle of the pulse width modulator is reduced quickly to a lower value and thereafter increased in a controlled fashion to accomplish a soft start.",
"In accordance with an embodiment of this invention that automatically adapts to clutches of different sizes and current ratings, a normalization factor is used to scale the raw current measured by a current sensor such as an A/D converter by a normalization factor so that the clutch current varies by a scaled value between zero and 100% without regard to the actual maximum clutch current.",
"The clutch current used by the controller to set the ramp current and to detect pull-in is described by the following equation: ClutchCurrent=CurrentNormalizationFactor*Raw A/D where Raw A/D is the unscaled, current measured through the solenoid.",
"The invention contemplates determining the CurrentNormalizationFactor in several different ways.",
"In accordance with one aspect of the invention the CurrentNormalizationFactor is based on RawA/D current measured at time t after the clutch is energized.",
"In accordance with another embodiment of this invention the CurrentNormalizationFactor is based on RawA/D current measured after the clutch solenoid has reached saturation.",
"Because saturation occurs after the soft start has already occurred, the value is stored in nonvolatile memory for the next soft start.",
"In accordance with another aspect of this invention, pull-in detection is improved.",
"While defining pull-in as a predefined drop in current below a stored maximum reference current detects pull-in in many instances, the present invention improves detection in those cases where pull-in is not distinct.",
"In accordance with the invention the coil current waveform is sampled for example at 1 ms intervals and the rate of change of current over a predetermined time is calculated.",
"This approximates the derivative of the coil current waveform over time (di/dt) and pull-in is defined to occur when di/dt falls below a Pull-InThreshold.",
"By combining this technique with the detection of a sharp pull-in signature, the onset of pull-in may be reliably determined.",
"In accordance with another aspect of this invention, a clutch controller is provided having an adaptive pull-in detection threshold.",
"Because the current through a solenoid necessary to pull in a clutch increases with clutch wear, a fixed Pull-in Threshold is not an accurate way to detect actual pull-in.",
"In accordance with this invention, the rate of change of solenoid current with respect to time is compared to a calculated current wave form and the Pull-in Threshold is adjusted to accurately detect pull-in at different magnitudes of clutch current so as to adapt to clutch wear.",
"In accordance with another aspect of this invention, engine RPM is used to actively control the current supplied to the clutch solenoid.",
"Where the clutch controller is used on a spark ignited internal combustion engine, the ignition pulse period can be used to derive engine RPM.",
"RPM droop provides a simple approximation of the load on the driving motor and is therefore particularly useful in adjusting the clutch engagement profile.",
"In accordance with another aspect of the invention, the BaseRamp that can be initially defined as derived solely as a percentage of the normal current range is modified over time based on accumulated data from prior clutch engagements.",
"In accordance with one aspect of the invention, the difference between the calculated BaseRamp and the actual BaseRamp at the start and end of the ramp are integrated with previous engagement errors at these points and applied to the BaseRamp starting and ending values, thereby adjusting the BaseRamp slope and offset for the next clutch engagement.",
"In accordance with another aspect of the invention, if desired, once the clutch is fully engaged, the current through the coil may be reduced to a holding value that is somewhat less than the current required to actuate the clutch, by adjusting the duty cycle of the pulse width modulated control power to a holding value.",
"This feature reduces solenoid coil heat dissipation, thereby enabling the use of a higher power solenoid than would be possible without this adjustment.",
"In accordance with a further aspect of this invention the condition of a partial pull-in is accommodated by allowing the current to build beyond the detected pull-in point.",
"When the current through the solenoid exhibits a large sharp drop, this indicates that complete pull-in has occurred and little or no additional current build time is needed or desired.",
"When the change in current at pull-in is indistinct, an adaptive Pull-in Threshold (ApiInsuranceThr) is calculated based on the difference between the maximum pull-in current and the minimum current drop after pull-in is detected.",
"While the novel aspects of the invention are set forth with particularity in the appended claims, the invention itself together with further objects and advantages thereof may be more readily comprehended by reference to the following detailed description thereof taken in conjunction with the accompanying drawing in which: BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) FIG. 1 is a diagrammatic view of an arrangement for actuating an electric clutch utilizing the soft start clutch controller of this invention;",
"FIGS. 2A and 2B are diagrammatic views of the idealized engagement of a clutch of the type to which the invention relates;",
"FIGS. 3A through 3C are diagrammatic views of the typical engagement of a clutch of the type to which this invention relates;",
"FIG. 4 is a graphical representation of the current flowing through a clutch solenoid in accordance with one aspect of this invention;",
"FIG. 5 is a graphical representation of the current through a solenoid in accordance with another aspect of this invention;",
"FIG. 6 is a graphical representation of current normalization using the saturation value as a reference.",
"FIGS. 7 , 8 , and 9 are graphical examples of adaptive pull-in insurance;",
"FIG. 10 is a graph of prior art pull-in detection failing to detect an indistinct pull-in signature;",
"FIG. 11 is a graph of the derivative based pull-in detection method showing one sample before pull-in is detected on a distinct pull-in signature;",
"FIG. 12 is a graph of the derivative based pull-in detection method showing the sample where pull-in is detected on a distinct pull-in signature;",
"FIG. 13 is a graph of the derivative based pull-in detection method showing one sample before pull-in is detected on an indistinct pull-in signature;",
"FIG. 14 is a graph of the derivative based pull-in detection method showing the sample where pull-in is detected on an indistinct pull-in signature;",
"FIGS. 15 , 16 , and 17 are graphical representations of clutch current versus time showing adaptive pull-in detector threshold in accordance with this invention;",
"FIG. 18 is a graphical diagram of how the fixed pull-in threshold is determined;",
"FIG. 19 is a graph of input shaft RPM and current with respect to time for a clutch controller employing active load feedback in accordance with the invention;",
"FIG. 20 is a flow chart describing period normalization;",
"FIG. 21 is an example of period normalization;",
"FIG. 22 is a block diagram of the controller structure for RPM feedback;",
"FIGS. 23-26 are graphical representations of actual performance of a clutch controller in accordance with the invention;",
"FIG. 27 is a graph of input shaft load and current with respect to time for a clutch controller employing active load feedback in accordance with the invention;",
"FIG. 28 is a block diagram of the clutch control system of this invention with load feedback after pull-in is detected;",
"FIG. 29 is a block diagram of a load feedback arrangement in accordance with this invention with long term BaseRamp;",
"FIG. 30 is a block diagram of the controller structure for long term base correction for load;",
"FIG. 31 is a software block diagram of a softstart algorithm for the clutch controller shown in FIG. 6 ;",
"FIG. 32 is a software block diagram of a current control PWM algorithm for the clutch controller of FIG. 6 .",
"FIG. 33 is a schematic diagram of a clutch controller in accordance with this invention;",
"and FIG. 33 is a schematic diagram of a controller in accordance with the invention.",
"DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a diagrammatic view of a clutch arrangement utilizing a clutch controller in accordance with this invention.",
"A clutch 10 includes an input connector 12 for connecting clutch 10 to soft start clutch controller 18 by way of first and second electrical conductors 14 and 16 .",
"Conductors 14 and 16 are connected to output terminals 20 and 22 of clutch controller 18 .",
"Clutch controller 18 also includes input terminals 24 and 26 .",
"Input terminal 26 is conventionally connected to ground while input terminal 24 is connected to a source of 12 volt DC power such as a battery 30 by way of a power switch 28 .",
"When power switch 28 is closed, clutch controller 18 applies power to clutch 10 by way of connector 12 as will be described in more detail below.",
"Input 302 is connected to a an insulated wire that is wrapped around the insulation of a high tension spark plug wire, for example 3 to 4 turns, to capacitively couple pulses from the spark plug wire to the input.",
"FIGS. 2 and 3 are diagrammatic illustrations showing clutch engagement under ideal and typical circumstances.",
"As shown in FIGS. 2( a ) and 3 ( a ), when disengaged, the clutch driven side and the clutch output side are spaced apart so that no power is transferred between them and moreover the outside clutch plate is ideally disposed parallel to the driven side clutch plate.",
"As the clutch is drawn in, in an ideal clutch, the output side clutch plate remains parallel to the driven side clutch plate as shown in FIG. 2( b ) and engages substantially simultaneously over the entire surface.",
"In practice, as shown in FIG. 3 , while it is often possible to maintain the driven side and output side clutch plates essentially parallel when the clutch is disengaged, when the clutch is engaged, the output side clutch plate may contact the driven side clutch plate obliquely as shown in FIG. 3( b ) and subsequently move into the position shown in FIG. 3( c ).",
"As shown in FIGS. 3( b ) and 3 ( c ), some clutch manufactures use a permanent magnet brake on the back side of the clutch plate which further exaggerates this problem.",
"This invention allows for this common effect.",
"FIGS. 4 and 5 are graphical representations of the current applied to a clutch solenoid in accordance with first and second basic open loop embodiments of the invention.",
"Referring to FIG. 4 , the current is shown on a vertical axis against time shown on the horizontal axis.",
"When the clutch is engaged, for example when switch 28 as shown in FIG. 1 is closed, the current begins to increase with time at a rate determined primarily by the inductance of the clutch solenoid.",
"As the current increases, the clutch controller monitors the current and elapsed time, calculating the CurrentNormalizationFactor at time t. Referring to FIG. 4 , a graph of current versus time is shown to illustrate the manner in which a controller in accordance with this invention adapts to clutches of various sizes and current ratings.",
"Normalization of the current is used to automatically scale the raw A/D value to ClutchCurrent so that ClutchCurrent is targeted to reach approximately 100% at clutch coil saturation.",
"After current is applied to a clutch, the current flowing through the clutch is measured after a pre-determined time t and stored as Raw Reference A/D.",
"Raw Reference A/D is used to calculate a normalization factor according to the equation: CurrentNormalizationFactor=Target/Raw Reference A/D Normalization Factor is then used to scale Clutch Current as follows: ClutchCurrent=CurrentNormalizationFactor*Raw A/D The target is a predetermined value, chosen to provide a normalized 100% maximum value of ClutchCurrent for any sized clutch.",
"ClutchCurrent is then used for all clutch control functions.",
"In this example, Target is approximately 20%.",
"An alternate normalization method is calculated from the saturation current which has been previously measured after the clutch has reached saturation as shown in FIG. 6 .",
"This occurs after the soft start portion of the clutch actuation has occurred and the saturation value is stored in non-volatile memory for the next soft start.",
"In this example, Target is 100%.",
"Nv Normalization Factor=Target/RawReference A/D Referring again to FIG. 4 , ClutchCurrent continues to build after time t until the controller detects a local maximum where the current begins to decrease.",
"Normally, this maximum occurs just as contact is first made between the driven side and the output side of the clutch which increases the inductance of the coil and reduces the current.",
"When the current through the clutch solenoid decreases to 95% of the MaxPull-in Current, the start of clutch engagement is declared and CurrentSetpoint is set to the Ramp begin value of 20% of the normalized current range.",
"When the measured ClutchCurrent has decreased to CurrentSetpoint at Ramp begin value, current is again supplied to the clutch solenoid but at a controlled ramp rate to facilitate a smooth engagement of the clutch.",
"Preferably, the controlled rate is a linear ramp but other controlled increases in current are also contemplated as described below.",
"When the end of the ramp is reached, the clutch should be fully engaged.",
"CurrentSetpoint is set to 100% to ensure full engagement and current is applied to the coil at a rate limited only by the coil inductance.",
"FIG. 5 shows a graph of the current through a clutch solenoid vs.",
"time in accordance with another embodiment of the invention having an additional feature adapted for uneven engagement of the clutch plates as shown in FIG. 3 .",
"The wave form of FIG. 5 compensates for partial pull-in which would otherwise be detected as full pull-in, causing the current through the clutch solenoid to be reduced and the clutch to either disengage or, drag along the output disc edge until the ramp current increases to a point where the clutch disc pulls in fully, resulting in a delayed and abrupt engagement.",
"As shown in FIG. 5 , when the maximum current is detected, a set point is established at 95% of the maximum current to detect the beginning of clutch engagement as shown in FIG. 4 .",
"When the current falls below 95% of the maximum current, the maximum current is saved as “MaxPull-in Current”, a new current set point is established at 1.2 times the MaxPull-in Current and power is continuously applied to the clutch until the new current set point is reached whereupon power to the clutch solenoid is removed and the current begins to decrease with time at a rate again determined primarily by the inductance of the solenoid to a point equal to 20% of the normalized current range.",
"At this point, the current ramp up proceeds as already described in connection with FIG. 4 .",
"This second embodiment allows for the initial reduction of current caused by the sort of uneven initial contact illustrated in FIG. 3( b ) by continuing to apply current until a higher threshold is reached thereby providing “pull-in insurance”",
"that actual clutch contact has occurred.",
"Because of mechanical variations during operation varying degrees of pull-in may occur.",
"Allowing the current to build to 1.2 times MaxPull-in Current after a complete pull-in is unnecessary and may cause a harsh engagement.",
"When a sharp drop in current occurs, complete pull-in is indicated and little or no additional current build time is needed or desired.",
"A less distinct drop indicates a partial pull-in which requires current to build to a higher level.",
"To account for variations in pull-in, as shown in FIGS. 7 and 8 , an adaptive pull-in insurance threshold (ApiInsuranceThr) replaces the fixed threshold of 1.2 times MaxPull-in Current previously described.",
"ApiInsuranceThr varies based on the difference between the MaxPull-InCurrent and the MinPull-InCurrent recorded after pull-in is detected according to the following formula: ApiInsuranceThr=MaxPull−InCurrent×PiBuildFactor−PiQualFactor×(MaxPull−InCurrent−MinPull−InCurrent) To account for changes in MinPull-InCurrent, ApiInsuranceThr is continually recalculated and compared to ClutchCurrent (the measured current).",
"Once ClutchCurrent exceeds ApiInsuranceThr, normal ramping commences.",
"PiBuildFactor and PiQualFactor are constants.",
"Typical values are: PiBuildFactor=1.5 PiQualFactor=2 As the clutch nears the end of its life, the current may not reach ApiInsuranceThr before coil saturation is reached.",
"To ensure that the softstart occurs within a reasonable timeframe, a timeout is added according to the following rule: Allow current to build until current is greater than or equal to ApiInsuranceThr or timeout occurs.",
"As shown in FIG. 7 , for a relatively new clutch with little vibration, the onset of pull-in is distinct and easily recognized.",
"Because of the large difference between MaxPull-InCurrent and Min Pull-in Current, ApiInsuranceThr is set relatively low and ramping begins relatively quickly after the onset of pull-in is detected.",
"As shown in FIG. 8 , when pull-in is less distinct, ApiInsuranceThr is greater, thus allowing more time for current to build before ramping begins.",
"This allows current to build beyond MaxPull-InCurrent to be certain that pull-in has actually occurred.",
"As shown in FIG. 9 , the combination of extra pull-in time and pull-in insurance timeout due to coil saturation are shown.",
"The pull-in signature is relatively indistinct as in the example shown in FIG. 28 , and moreover, coil saturation occurs before the current reaches ApiInsuranceThr.",
"Accordingly, after PI timeout, the ramp phase is initiated automatically.",
"While the embodiments of the invention described above provide adequate performance in many situations, especially where a distinct drop in current occurs when the clutch armature (clutch disc) pulls in to contact the electromagnet, this distinct current signature, as shown in FIG. 4 , occurs reliably only when the armature pulls in squarely towards the electromagnet in one quick fluid motion.",
"In many practical applications, the current signature may be less distinct if the armature pulls in obliquely or if the armature assembly is vibrating as shown in FIG. 10 .",
"Vibration of the armature can cause a variation of the inductance as the armature distance varies at the vibration frequency.",
"The change in inductance will cause a resulting modulation of the current waveform.",
"The effect is most pronounced just before the pull-in point as the electromagnet begins to pull the armature closer.",
"Vibration and oblique pull-in may occur together especially in a case where a permanent magnet brake is employed.",
"In this case the edge of the armature opposite the brake magnet typically pulls in first causing a relatively small change in inductance and consequently a small change in current.",
"The disk may then peel off the permanent magnet causing several more small changes in inductance rather than one large distinct change.",
"The Pull-in Threshold may be reduced below 5% to compensate for this but this is generally undesirable because it increases the likelihood of false or premature triggers due to noise or armature vibration alone.",
"As can be seen, the current does not fall below the magnitude required to indicate a pull-in, and consequently, after the clutch is actually pulled in, the current continues to increase uncontrolled to saturation.",
"FIG. 10 is a graph of current versus time showing these effects.",
"The current increases relatively smoothly from the origin initial current 100 to a first current maximum indicated at 102 .",
"Subsequently, as the clutch begins to pull in, clutch vibration causes a series of local minima and maxima 104 of current to occur none of which causes the current to fall below the preselected threshold such as 5% of the maximum current.",
"Consequently, the current is not reduced sufficiently for detection in accordance with the method described above and following the undetected partial pull-in, the current continues to increase to a maximum commencing at time 106 .",
"In accordance with another aspect of this invention, a plurality of current samples is taken but instead of merely storing the highest current value and presuming clutch pull-in when the current falls below that value by a predetermined percentage such as 5%, the rate of change of current with respect to time (di/dt) is calculated from the sample current values.",
"When di/dt falls below the Pull-in Threshold, pull-in is detected and the controller takes over control of the current to begin the soft start ramp period.",
"While the examples described herein use 7 one millisecond samples, both the duration of the samples and the number of samples may vary somewhat.",
"The length of the samples and the number of samples evaluated to determine di/dt are preferably selected to provide a reliable indication of pull-in without overloading the microprocessor that makes the calculations.",
"FIGS. 11-13 show examples of this technique where Pull-in Threshold is set to one.",
"As shown in FIG. 11 , the current is sampled every 1 ms and the magnitude of the current detected during each sample is used to compute a derivative of the current with respect to time over a predetermined number of samples, for example 5 to 20, in this case seven.",
"In the example shown in FIG. 11 the derivative is 6.9 which is above Pull-in Threshold resulting in no pull-in having occurred over this interval.",
"FIG. 12 shows the same graph as FIG. 11 at the point where pull-in is detected.",
"The one millisecond samples are summed over a subsequent seven millisecond period, but in this case, in the last sample of the new period, the current drops by five and the derivative is plus 0.3.",
"Since this is less than the Pull-in Threshold of 1, pull-in is detected.",
"FIGS. 13 and 14 show the application of the derivative pull-in detection method to a clutch where a sharp pull-in signature is not present.",
"The figures show the current with respect to time which is the same in each of the two figures.",
"In FIG. 13 , the 7 one millisecond samples are summed to produce the derivative di/dt.",
"In this case, the sum is 2.0.",
"With a Pull-in Threshold of 1, pull-in is not detected at this time.",
"FIG. 14 shows the same window, but one sample later.",
"The derivative di/dt is now 0.6 and with a Pull-in Threshold of 1, pull-in is detected.",
"This demonstrates that the derivative method can be used to detect pull-in in situations such as the one shown in FIG. 10 where the previously described method would not detect pull-in.",
"As already discussed, pull-in is detected by continuously monitoring the clutch current and noting the characteristic decrease in current when pull-in occurs.",
"A threshold is established to avoid false sensing due to irregularities not indicative of clutch pull-in.",
"A problem with known clutch controllers is that a fixed Pull-in Threshold does not account for clutch wear and may result in the failure to detect pull-in of a worn clutch.",
"FIG. 15 is a graph of current versus time for a new clutch showing early pull-in.",
"FIG. 17 is a graph of current versus time for a worn clutch showing late pull-in.",
"As can be seen, the rate of change of current with respect to time at pull-in for a new clutch is much higher than the rate of change of current with respect to time for a worn clutch.",
"A single Pull-in Threshold cannot accurately detect pull-in in both of these situations.",
"In accordance with this invention, the Pull-in Threshold must be changed as the point on the current versus time graph at which pull-in occurs changes.",
"In accordance with this invention, as shown in FIG. 16 , a synthesized current waveform is generated to approximate the actual current through a clutch coil inductor over time.",
"The synthesized current does not simulate the reduction in current produced by pull-in, so that it is essentially a calculated curve based upon the inductance the solenoid, the applied voltage, and other factors.",
"The synthesized current waveform can be stored as an equation or a look-up table for faster response.",
"The synthesized current waveform is adjusted to be at the same scale as the clutch current so that at saturation, the synthesized current equals the clutch current.",
"In accordance with the invention, as shown in FIG. 18 , a fixed threshold is set to one half the expected drop in current produced by a typical pull-in.",
"That is, if the drop in current during pull-in is expected to be 4, the fixed threshold is set to 2.",
"The Pull-in Threshold is then set equal to the synthesized change in current minus the fixed threshold.",
"The synthesized change in current is the change in current versus time for a predetermined time period, in this example 15 milliseconds.",
"Referring to FIG. 15 , it can be seen that for a new clutch, pull-in occurs at a relatively low current, whereas, as shown in FIG. 17 , for a worn clutch, pull-in occurs at a higher current.",
"The synthesized change in current at the low current pull-in point is 10, while the synthesized change in current at the high current pull-in point is 2.",
"The value for the fixed threshold is set to 2, one-half the expected drop of 4.",
"Applying these numbers to the formula, for a new clutch the change over 15 milliseconds immediately preceding the time of pull-in is 10.",
"Subtracting 2 yields 8.",
"For a worn clutch, the change in current over 15 milliseconds just prior to the time of pull-in is 2, and the Pull-in Threshold is therefore 0.",
"Up to this point all of the elements of the basic softstart controller operating in an open loop mode have been described.",
"In accordance with another aspect of this invention, the invention relates to a method of controlling the solenoid current during the period at which the current is supplied to the solenoid at a controlled rate.",
"Referring to FIG. 19 , the initiation of a pull-in is detected in one of the ways already described, that is by noting a drop in the absolute current flowing through the solenoid or by comparing the rate of change of the current to a pre-determined value.",
"Once the commencement of a pull-in has been detected, the current to the solenoid is reduced to begin commencement of the controlled engagement ramp period.",
"Subsequently, BaseRamp current is increased during the controlled engagement period.",
"Simultaneously, the ActualRPM of the input shaft is compared to a DesiredRPM profile and an Error signal is generated.",
"The Error equals the ActualRPM minus the DesiredRPM times the configuration gain, an amount determined in advance.",
"The current is adjusted by adding the Error determined from the ActualRPM to the base current.",
"In this way, by adjusting the current, the error between the ActualRPM and the DesiredRPM is minimized.",
"Once the actual current has increased to a pre-selected level, complete clutch engagement is presumed and the current is thereafter permitted to increase at a rate limited by the coil inductance as has already been discussed.",
"RPM droop is an approximation of engine load and as such the DesiredRPM profile may be selected to provide a number of different levels of soft engagement.",
"One method is to decrease the RPM linearly from about 95% of the ReferenceRPM at the beginning of clutch engagement to about 60% of the ReferenceRPM at full engagement.",
"Note that the 95% RPM beginning point is chosen to account for the approximate initial RPM drop that occurs while the clutch coil current is decaying during the period between when pull-in occurs and when the ramp up begins.",
"A method for controlling clutch engagement in accordance with this invention may be summarized as follows.",
"All references are to FIG. 19 .",
"Immediately after power up, CurrentSetpoint is set to 100% duty cycle to apply maximum DC power to the armature coil.",
"At time t CurrentNormalizationFactor is calculated as described previously.",
"Immediately before engagement commencement, the ReferenceRPM is captured.",
"Preferably, the RPM is captured right before pull-in is detected.",
"While it is possible to measure RPM directly, it may be more convenient to measure the period of a signal related to RPM such as the period between spark pulses.",
"This period can be used directly or converted to RPM according to the formula RPM=60/period.",
"Where period is the time in seconds between pulses.",
"In accordance with one aspect of the invention the ReferenceRPM or reference period is normalized to a constant at the time of measurement.",
"This has two advantages.",
"Without normalization, the loop gain of the control loop will vary as the RPM changes.",
"For example, a 10% error at 2000 RPM is 200 RPM while a 10% error at 4000 RPM is 400 RPM.",
"Normalization makes these two the same.",
"Normalization also permits the software to operate independently of system configuration differences such as the number of spark pulses per revolution or the actual engine speed.",
"This allows the controller to be used for example on two and four cycle engines as well as on engines operating at different normal speeds, without modification.",
"FIG. 20 is a block diagram of an exemplary method for determining the normalized period from a measured period and a predetermined reference period.",
"Normalization has a second advantage.",
"The period is often measured as a 16-bit number.",
"When an 8-bit microprocessor is used to keep costs low, processing 16 bit numbers is computationally inefficient.",
"By normalizing the period, the 16-bit number may be converted to an 8-bit number without substantially affecting the dynamic range of the measurement.",
"FIG. 21 provides an example of period normalization.",
"Immediately after beginning, pull-in is tested.",
"If pull-in has not occurred, the process loops back until pull-in is detected.",
"Once pull-in is detected, the reference period is set to a stored value, in this case 20,000 us and the normalization factor is set equal to 20,000 divided by 100, yielding a normalization factor of 200 in this case.",
"The normalized period is then continuously recalculated until the ramp has been completed and the routine exits.",
"Pull-in is then detected using either the derivative method or the fixed current drop method described above.",
"Once the initiation of pull-in has been detected, the BaseRamp current profile is generated as described previously.",
"The BaseRamp profile is typically chosen for optimum open loop soft start performance.",
"Simultaneously, the DesiredRPM profile is generated.",
"DesiredRPM profile is the desired engine droop rate for a normal engagement based on a percentage of the ReferenceRPM.",
"This profile may be linear or non-linear over time and is based on a percentage of the ReferenceRPM captured in Step 3.",
"In the example shown in FIG. 19 , the start of the DesiredRPM Profile is 95% of the ReferenceRPM, and the end of the DesiredRPM Profile is 60% of the ReferenceRPM.",
"The ActualRPM is then continuously compared to the DesiredRPM profile and an error signal is generated.",
"The error is the difference between the ActualRPM and the DesiredRPM.",
"The error is scaled by the configuration gain constant selected for optimum loop stability.",
"Error is the difference between the DesiredRPM Profile and the ActualRPM at any given time scaled by the ConfigGain.",
"AdjustedRamp is the BaseRamp plus the error, and therefore is the actual CurrentSetpoint that is applied to the clutch coil.",
"Adding Error to BaseRamp will vary the coupling of the load to the engine with the goal of fitting engine RPM as closely as possible to the DesiredRPM profile.",
"For clarity of explanation, the method just described used a simple proportional controller.",
"FIG. 22 shows a block diagram of the controller for this embodiment.",
"In FIG. 22 the Error term is fed into a ControlSystem block where it is conditioned before being added to BaseRamp.",
"There are many different control system topologies that will prove effective, but a PID controller will provide good results.",
"The efficacy of the soft start clutch and the method described herein may be more readily appreciated by a reference to the results of tests made on the clutch, which results are shown in FIGS. 23 and 24 .",
"FIG. 23 shows the results of a first test in which the ramp current was set for a very soft engagement with the ramp starting at 80 and ending at 110.",
"No feedback was employed.",
"The engine RPM is shown by trace 400 and the output shaft RPM is shown by trace 410 .",
"As can be seen, although the output shaft RPM increases gradually, the engine shaft RPM shows a significant dip at the end of the ramp, illustrating excessive slippage throughout the ramping period.",
"In FIG. 24 , feedback in accordance with this invention is employed and the output shaft RPM shown by trace 420 increases smoothly while there is a significantly reduced dip in the engine shaft RPM 440 , thus indicating a soft engagement.",
"The results of a second test are illustrated at FIGS. 25 and 20 .",
"In this case, the ramp was set for a harsh engagement, the ramp starting at 150 and ending at 200.",
"In FIG. 19 , no feedback is employed and a very sharp dip in engine shaft RPM is observed at the time of clutch engagement.",
"In FIG. 26 , with feedback in accordance with this invention, the dip in engine shaft RPM is significantly reduced, thus indicating a soft start in accordance with the invention.",
"In the previous example RPM droop was used as a simple approximation of engine load.",
"More direct measurements of load can of course be used.",
"For example, the current and voltage supplied to an electric motor may be measured as ActualLoad and applied to the control system shown in FIG. 28 .",
"FIG. 27 graphically illustrates a general example of load feedback.",
"Immediately after power up, CurrentSetpoint is set to 100% duty cycle to apply maximum DC power to the armature coil.",
"At time t CurrentNormalizationFactor is calculated as described previously.",
"Pull-in is then detected using either the derivative method or the current draw method described above.",
"Once the initiation of pull-in has been detected, the BaseRamp current profile is generated as described previously.",
"Simultaneously, the DesiredLoad profile is generated.",
"The DesiredLoad profile is the desired motor load rate for a normal engagement based either on predetermined values or as a percentage of ReferenceLoad which had been captured and stored from previous soft starts.",
"This profile may be linear or non-linear over time.",
"In the example shown in FIG. 19 , the start of the DesiredRPM Profile is offset above zero to account for initial uncontrolled loading that occurs when the solenoid current is decaying between the time that pull-in occurs and the time that the ramp begins.",
"Error is the difference between the DesiredLoad Profile and the ActualLoad at any given time scaled by the ConfigGain.",
"AdjustedRamp is the BaseRamp plus the error, and therefore is the actual CurrentSetpoint that is applied to the clutch coil.",
"For clarity of explanation, the method just described used a simple proportional controller.",
"FIG. 28 shows a block diagram of the controller for this embodiment.",
"Referring now to FIG. 29 , an arrangement similar to FIG. 28 is illustrated with long term feedback added.",
"The elements of FIG. 29 that are the same as in FIG. 28 are identified with the same reference numbers.",
"As can be seen, the error at the beginning and ending of the ramp is sampled by closing switches 61 , 63 , and 65 and integrating the error over time.",
"Any number of multiple switches and integrators may be added as represented by the dotted line example at t=x.",
"The integrated error is then applied to the BaseRamp for subsequent starts so that the error is minimized.",
"BaseRamp is used as described previously, in FIGS. 28 and 30 .",
"FIG. 30 shows a controller example which uses long term feedback exclusively.",
"It is essentially the same as the controller described in FIG. 29 with real time feedback removed.",
"As can be seen, the error at the beginning and ending of the ramp is sampled by closing switches 61 , 63 , and 65 and integrating the error over time.",
"Any number of multiple switches and integrators may be added as represented by the dotted line example at t=x.",
"The integrated error is then applied to the BaseRamp for subsequent starts so that the error is minimized.",
"In accordance with another embodiment, the current normalization may be eliminated altogether and replaced by a conventional factory calibration of the ClutchCurrent.",
"FIG. 31 is a flowchart showing how the basic software in microcontroller 160 operates to implement the invention.",
"On boot up, either upon the initial application of power or upon the system being reset, an initialization routine as shown at 40 is performed.",
"The current set point is set to zero while a delay period at 42 elapses to wait for the system to stabilize.",
"The CurrentSetpoint is initialized to 100% at 44 , and clutch coil current begins to build limited only by its L/R time constant.",
"At time t shown by 46 , the software captures a RawA/D sample to be used in the CurrentNormalizationFactor calculation at 48 .",
"At 50 , the controller software loops at a 1 ms rate while repeatedly calculating Derivative and updating SynthesizedCurrent.",
"Derivative is then compared it to the Pull-in Threshold which is derived from SynthesizedCurrent.",
"At 52 , immediately after pull-in is detected ReferencePeriod is captured where it is used in the PeriodNormalizationFactor calculation at 53 .",
"ClutchCurrent continues to build while it is compared against ApiInsuranceThreshold in 54 .",
"When ClutchCurrent exceeds ApiInsuranceThreshold at 56 , the first BaseCurrent point is generated.",
"At essentially the same time the first DesiredRPM point is generated at 58 .",
"At 60 Error is calculated by Subtracting DesiredRPM from ActualRPM.",
"A new CurrentSetpoint is produced at 61 .",
"If End of Ramp has not occurred at 62 , the process is repeated where the next ramp points are generated and a new Error calculation is made.",
"At 63 CurrentSetpoint is set to 100% to ensure that the clutch is fully engaged.",
"FIG. 32 is a software block diagram showing the manner in which the controller shown in FIG. 6 controls the current through the clutch solenoid.",
"The current is sampled by measuring a voltage across resistor 132 at a rate of 50 kHz.",
"The analog to digital conversion occurs within controller 160 .",
"The current is averaged every 50 samples, that is approximately 1,000 times per second, in block 66 and the average current is compared to the CurrentSetpoint minus hysteresis in block 68 .",
"If the current is below the CurrentSetpoint FET 123 is turned on in block 70 and the saturation detector 220 is tested in block 72 .",
"If the current is higher than the saturation current and the over current timeout has expired as tested at block 74 then the FET is latched off in block 76 .",
"As long as the saturation current is not exceeded or is exceeded only for a short time the routine terminates in block 78 .",
"Returning to block 68 , if the current is greater than the CurrentSetpoint minus hysteresis and continues to increase until it is greater than the CurrentSetpoint as tested in block 80 , the FET is turned off in block 82 , the over current timeout is reset in block 84 and the routine terminates in block 78 .",
"If the current is not greater than the CurrentSetpoint as tested in block 80 then the routine terminates at block 78 .",
"FIG. 33 is a schematic diagram of a clutch controller in accordance with another embodiment of the invention.",
"A power source such as a 12 V DC power source is connected to an input terminal 102 .",
"Terminal 102 is connected by way of a diode 104 to an input terminal 106 of a voltage regulator 108 .",
"Regulator 108 has a ground terminal 110 and an output terminal 112 that provides an operating voltage for example 4.7 V to the other elements of the clutch controller as will be discussed in more detail below.",
"A filter capacitor 114 filters the output of voltage regulator 108 and the filtered output is available on terminal 116 .",
"Input terminal 102 is also connected to the source terminal 120 of field effect transistor 122 .",
"Drain 124 of FET 122 is connected to a first clutch solenoid terminal 126 .",
"The other end of the clutch solenoid is connected to terminal 128 which is connected to ground through low resistance resistor 132 which may have resistance of approximately 0.1 ohm.",
"Resistor 132 is connected in such a way that both the ON and OFF current through the clutch solenoid may be measured by sensing the voltage drop across resistor 132 .",
"Ground is connected to output terminal 130 .",
"A snubber diode 134 is connected between terminal 126 and ground to provide a path for the clutch solenoid recirculating current during the PWM off period.",
"Gate electrode 136 of FET 124 is clamped to a maximum gate-source voltage of approximately 10V by zener diode 138 .",
"Gate terminal 136 is connected to the collector of gate drive transistor 140 by current limiting resistor 142 which may have a value of approximately 390 ohms.",
"A zener diode, preferably a 20 V zener diode 144 is connected between the collector and the emitter of transistor 140 to limit the voltage applied to transistor 140 during a “load-dump”",
"transient.",
"Load-dump transients can occur when the 12V battery is suddenly disconnected from a running engine's charging system.",
"Zener diode 144 also forces FET 122 ON during the load dump, both to keep FET 122 's drain-source voltage within safe limits and to help to suppress the load-dump by providing a load via the clutch.",
"Collector 146 of transistor 140 is connected to the 12 volt source through resistor 148 which is preferably a 1.5 K. ohm resistor.",
"Base 150 of transistor 140 is connected to an output of microcontroller 160 by a series resistor 162 .",
"Base resistor 164 is connected between the base 150 and ground and preferably has a value of approximately 2 K. ohms The current through the clutch solenoid coil is sensed as a voltage drop across resistor 132 which is connected through a filter comprising a series resistor 170 and a capacitor 173 to a non-inverting input 172 of a comparator 174 .",
"Preferably, resistor 170 has a value of approximately 2 K. ohms.",
"An inverting input 176 of comparator 174 is connected to ground through a series resistor 178 which preferably has a value of about 1000 ohms.",
"A feedback resistor 180 is connected between output 182 of comparator 174 and inverting input 176 .",
"The output of comparator 174 is connected to an input 190 of controller 160 through a filter comprising a series resistor 192 which preferably has a value of approximately 2 K. ohms and a capacitor 194 which preferably has a value of 0.01 μF.",
"The filtered current signal is also connected to the inverting input 198 of a comparator 200 whose non-inverting input 202 is connected to a voltage divider comprising a first resistor 204 which preferably has a value of approximately 20 K. ohms and a second resistor 206 which preferably has a value of approximately 10 K. ohms.",
"A filter capacitor 208 is connected in parallel with resistor 206 .",
"Comparator 200 provides a signal at output 210 when the current through the clutch solenoid exceeds a predetermined value set by the ratio of resistors 204 and 206 .",
"The current overload signal is applied to input 212 of controller 160 which is preferably an interrupt input.",
"The clutch controller uses a high side driver with the FET 122 switching the voltage provided to the clutch at terminal 126 and senses the current in the return path at terminal 128 .",
"In the case of an external short circuit to ground, the return path is bypassed.",
"In this case the FET 122 could see a dangerously high current while the sense circuit measured zero current.",
"The FET drain-source saturation voltage is dependent on the current and the FET R DSON of 0.06 ohms.",
"If the current is normal (<5 A), the FET will saturate to less than 0.3V across its drain-source.",
"As the current increases the saturation voltage increases.",
"Therefore, by monitoring the saturation voltage the approximate current through the FET can be sensed to provide short circuit protection.",
"A saturation detector comparator 220 has a non-inverting input 234 connected to a first voltage divider comprising resistors 222 and 224 connected between the FET drain terminal 124 and ground, and a second inverting input 235 connected to a second voltage divider comprising resistors to 226 and 228 connected between FET source terminal 120 and ground.",
"Zener diodes 230 and 232 limit the voltage is produced by the two voltage dividers to safe values but do not otherwise affect the comparison.",
"Preferably, resistor 222 has a value of approximately 75 K. ohms, resistor 224 has a value of approximately 10 K. ohms, resistor 226 has a value of approximately 100 K. ohms, and resistor 228 has a value of approximately 10 K. ohms.",
"Comparator 220 preferably has a feedback resistor 233 which may have a value of 1 meg.",
"ohm connected between its noninverting input 234 and its output 236 to provide a degree of hysteresis for the saturation detector.",
"Output 236 of saturation detector 220 is connected to an input 240 of microcontroller 160 .",
"Neglecting hysteresis resistor 232 , the resistor ratios are set up for a comparator transition with the FET source 120 at 12V and the drain 124 at 9.27V.",
"Therefore, if the drain is above 9.27V the comparator output 220 is high, below 9.27 it is low.",
"This gives a drain-source maximum of 2.73V—this threshold was set high to ensure that there would be no false trips.",
"It could be reduced significantly to reduce maximum short circuit current.",
"A sensor 300 is coupled to the ignition circuit of the engine being controlled and to microprocessor 160 for measuring the RPM of the engine.",
"As shown in FIG. 1 , input 302 is connected to a an insulated wire that is wrapped around the insulation of a high tension spark plug wire, for example 3 to 4 turns, to couple pulses from the spark plug wire to the input 302 of the sensor.",
"Input 302 is capacitively coupled to the base 304 of transistor 306 .",
"The negative going portion of the coupled spark signal turns on transistor 306 and produces a positive going edge at collector 308 which is coupled to the timer input 310 of microcomputer 160 .",
"The microcomputer preferably includes an interrupt routine for measuring the period between positive edges of the pulses coupled to the microcomputer for determining the RPM of the engine.",
"While the invention has been described in connection with certain presently preferred embodiments thereof, those skilled in the art will recognize that many modifications and changes may be made therein without departing from the true spirit and scope of the invention which accordingly is intended to be defined solely by the appended claims."
] |
This application is a continuation of Ser. No. 08/489,816 filed Jun. 13, 1995, now abandoned, which is a continuation in part of Ser. No. 08/142,600 filed Oct. 28, 1993, now abandoned, which claims priority to German application 44 20 936.3 filed Jun. 16, 1994.
BACKGROUND OF THE INVENTION
1. Brief Description of the Invention
The instant invention relates to a novel method of in vivo diagnosis of upper gastrointestinal diseases.
2. Brief Description of the Prior Art
Factors adversely affecting the function of the gastrointestinal system in humans are exceedingly varied in their nature. Such disorders may arise in the upper or lower gastrointestinal tracts, or both. There is a broad range of causes of gastrointestinal disorders, including genetic, physiological, environmental and psychogenic factors. Accordingly, the diagnosis and management of these disorders can be exceptionally difficult.
Among the chronic disorders of the upper gastrointestinal tract are those which fall under the general categories of gastritis and peptic ulcer disease. The upper gastrointestinal tract is generally defined as including the esophagus, the stomach, the duodenum, the jejunum and ileum. Peptic ulcers are lesions of the gastrointestinal tract lining, characterized by loss of tissue due to the action of digestive acids and pepsin. It has generally been held that peptic ulcers are caused by gastric hypersecretion, decreased resistance of the gastric lining to digestive acids and pepsin, or both. Gastritis is, by definition, an inflammation of the stomach mucosa. In practice, though, the disorder is manifested by a broad range of poorly-defined, and heretofore inadequately treated, symptoms such as indigestion, “heart burn”, dyspepsia, and excessive eructation.
As with the management of any disorder, the rapid, precise, and accurate diagnosis of gastrointestinal disorders is of paramount importance. The typical means used to diagnose the gastrointestinal disorder presented by a given patient will depend upon such factors as the nature and severity of symptoms, the overall health of the individual, the medical history of the patient, the need for a specific diagnosis in order to implement a treatment with reasonable likelihood of success, and the availability of diagnostic devices. However, the diagnostic methods typically employed in the art are often slow, cumbersome, costly, and may yield equivocal or inaccurate results. Thus, for patients not having severe symptoms, a precise diagnosis of a gastrointestinal disorder might not be attempted. Such patients may simply be treated with conventional therapies, such as with antacids or drugs which inhibit stomach acid secretion. While such therapies might provide temporary symptomatic relief, a cure is often not effected. More effective treatments may depend upon better diagnoses of the actual underlying gastrointestinal disorder. In particular, it has been discovered that many such gastrointestinal disorders are mediated by infection of gastric mucosa by Helicobacter pylori. H. pylori is a Gram-negative spiral organism which produces the enzyme urease. The organism is predominantly found beneath the mucus layer of the luminal aspect of the gastric epithelium and in the gastric pits. Helicobacter can be diagnosed by blood test for antibodies, breath test, or biopsy of the stomach lining. Antibodies, however, can remain positive for many months after the bacteria have been eradicated. The presence of antibodies presents a falsely positive result in approximately 10 to 15% of patients. Biopsies are relatively quick; however, they add time, expense and risk. Although relatively minor, there is a 1 in 20,000 risk of bleeding from a biopsy site. Biopsies cannot be performed on patients who have a tendency to bleed, such as patients with hemophilia and liver disease. Additionally, it has recently been found that Helicobacter is patchy, thereby requiring multiple biopsies to obtain 100% accuracy. The cost for a biopsy is approximately $100. Biopsies also increase the risk of the person handling the tissue being exposed to HIV. If a urease test is used, the biopsy sample must be placed in the test by the nurse, thereby requiring an additional person during the test.
The prior art has disclosed testing for gastrointestinal disorders, the majority of which have been in vitro. Many tests have also been disclosed using urea and indicators.
Marshall, 4,748,113 discloses compositions and methods for the diagnosis of gastrointestinal disorders involving urease. Methods include obtaining a gastric sample material and contacting the material with a composition including urease and an indicator.
Marshall 4,830,010, discloses methods for the diagnosis of gastrointestinal disorders. The method steps include administration of urea-containing compositions prior to assay.
Steward et al, 5,139,934 disclose substrate compositions and method of urease assay. The method is an in vitro immunoassay that includes the use of pH indicators.
Nagatsu et al, 4,147,692 disclose methods and compositions for measuring enzymatic activities and correlating such activities with various disease states.
Kraffczyk et al, 3,873,369 disclose calorimetric indicators for the determination of urea.
Vasquez et al, 4,851,209 disclose in vivo diagnostic procedures for the clinical evaluation of gastrointestinal ulcer disease using radioactive isotopes. Procedures involve prior administration of a diagnostic pharmaceutical followed by scintigraphic imaging of the gastrointestinal area of interest with scintigraphic imaging equipment.
Although the use of urease or other indicators has been used in combination with pH indicators, all except Vasquez et al are conducted in vitro.
The instant invention discloses a method of detecting the alkaline pH change in vivo. The test dramatically cuts down the number of biopsies required and is safe for patients having any bleeding tendencies while being rapid and low cost. Additionally, through the color change, it can be determined if the change is a true positive or a false positive reaction.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages of the instant disclosure will become more apparent when read with the specification and the drawings, wherein:
FIG. 1 illustrates the location of the beads in the stomach and the urea/ammonia transfer.
SUMMARY OF THE INVENTION
A method for the in vivo detection of urease-producing Helicobacter in the upper stomach is disclosed. A dense carrier is used which is divided into two separate groups, the first combined with a first reagent indicator and the second combined with a second reagent indicator and urea. The carriers are food soluble products, preferably sugar beads having a diameter of approximately 0.2 to 3.0 mm. The carrier and reagent can be combined through coating the carrier or combining the carrier and reagent. The treated carriers and urea are encapsulated in a soluble capsule which is administered to a patient. A buffer can be added, if desired, to obtain more specific results. The density of the carriers cause the capsule to descend to the gastric mucosa. The gastric juices dissolve the capsule containing the reagents and urea thereby placing the two reagents and urea combination in direct contact with the gastric mucosa. The urea reacts with any urease present on the mucosa, creating ammonia which causes the pH within the stomach to increase. The two reagents react differently, through color change, to the increase in pH, which is viewed through use of an endoscope. A preferred first reagent is bromothymol blue (dibromothymolsulfonphthalein), which changes yellow in the presence of urease, and a preferred second reagent is phenol red (phenolsulfonphthalein), which turns red in the presence of urease.
DETAILED DESCRIPTION OF THE INVENTION
The instant disclosure uses indicators to detect pH change, as a result of the presence of H. pylori in the stomach, during endoscopy. A change in the colors of the indicators reflects the pH change within the stomach; a certain combination indicating a pH reaction to the presence of Helicobacter, or H. pylori , organisms.
Urea has the formula H 2 NCONH 2 and is a naturally occurring product of protein metabolism. Gastric materials from humans or other animals having gastrointestinal disorders contain relatively large quantities of urease (urea aminohydrolase), which hydrolizes urea to ammonium carbonate or ammonia and carbon dioxide. Normally urease is present in the body in only trace amounts, performing the function of decomposing urea. H. pylori increases the amount of urease above normal in the affected areas. The increased urease reacts with the administered urea by creating ammonia, which causes an indicator color change due to the increased alkalinity.
The indicators useful in this invention are weak acids with sharply different colors in their dissociated (ionized) and undissociated (neutral) states. The indicators useful herein are medically approved and have pK a values of from about 6.5 to about 8.5, preferably from about 7.0 to about 8.0. The color exhibited by the indicator in the present composition will depend upon the pH of the composition, the particular indicator used, and the dissociation constant (K a ) for that indicator (i.e., pK a |log 10 K a ). As the color exhibited by the indicator changes over a range of pH values (pH=log 10 [H+]), the indicators useful in the present compositions change color over a pH range of from about 5.5 to about 9.0, preferably from about 6.5 to about 8.5. The pH of the present compositions are accordingly adjusted to a pH at least about one pH unit lower than the pK a of the indicator used (i.e. having a hydrogen ion concentration [H + ] ten times less than (10% of) the hydrogen ion concentration in a solution having a pH equal to the pK a of the indicator). Preferably, the pH is adjusted to a pH about two pH units below the pK a of the indicator. Adjustment of the pH of the present compositions can be effected by addition of a base (e.g. sodium hydroxide) or an acid (e.g. hydrochloric acid or citric acid). Thus, preferably, the pH of the composition of this invention is adjusted to a pH of from about 5.0 to about 6.5, with the preferred embodiment being from about 5.0 to about 6.0.
The preferred reagents are bromothymol blue (dibromothymolsulfonphthalein) indicator, Reagent 1, and phenol red (phenolsulfonphthalein) indicator, Reagent 2. Other indicators useful herein include p-nitrophenol, neutral red (2-methyl-3-amino-6-dimethylaminophenazine), quinoline blue (cyanine), cresol red (o-cresolsulfonphthalein), and thymol blue (thymolsulfonphthalein). The reagents used herein must have a pH indicator range which can reflect the range of pH encountered with the the stomach, generally between 5.5 to 9.0. Indicators approved for medical use and useful herein are described in the The Merk Index (9th ed. 1976), incorporated by reference herein. Reagents are commonly used in conjunction with biopsies, such as disclosed in U.S. Pat. Nos. 4,748,113 to Marshall and 3,873,269 to Kraffczyk, the disclosures of which are incorporated herein as though recited in full. Reagent 2 has urea added to react with the urease enzyme, if present. The urea penetrates the mucus layer of the stomach to come into contact with the urease-containing bacteria, H. pylori , on the stomach wall. The urea/urease combination creates ammonia which migrates outward through the mucus layer to come into contact with the Reagents.
The urea is added to a dense carrier, soluble in gastric juices, at approximately 1-20 grams per kilogram of carrier. The preferred carrier is beads, such as nu-pareil beads, although any carrier approved for pharmacological use can be used which has sufficient density to deposit the capsule to the stomach mucosa. The density of the carrier is critical in that it must be able to migrate, or descend to the gastric mucosa, therefore requiring a density, or weight, greater than that of the body fluids. Appropriate dense carriers for use in the medical arts will be readily known to those skilled in the art. It is preferred that the carrier have a neutral pH to prevent interference with the test results. In the event that the carrier has a non-neutral pH, acidic or alkaline ingredients should be incorporated within the capsule to compensate for the carrier's pH.
In the preferred embodiment the Reagents 1 and 2 are put into the stomach in a solid phase, such as beads, which can be individually identified in the stomach. The reagents should be coated onto small diameter beads, preferably 0.2-3.0 mm, with the preferred size being approximately 2 mm. The 2 mm. bead size provides the advantages of visibility as well as preventing obstruction of the endoscope in the event not all of the beads dissolve. A suitable method of making such beads would be to use sugar beads, such as nu-pareil seeds, with a mesh size of 25-35. The nu-pareil beads provide the density required to migrate to the mucosa, either in the capsule or after the capsule dissolves. A less dense vehicle, which floats within the gastric juices, would prevent the Reagents from being placed onto the mucosa.
The choice of the carrier is contrasted with those in the Stern and Brindamour patents wherein the carriers float within the gastric juices. U.S. Pat. No. 3,121,041, issued to Stern et al, discloses the use of a plug, impregnated with a radioactive material, in combination with a soluble capsule. The spongy plug disclosed in Stern would float within the gastric juices, providing several disadvantages. In order to obtain the contrasting results of the two reagents, two impregnated sponges must be used within the capsule, thereby increasing manufacturing expenses. The Stern et al patent discloses tapping the sponges into the capsule. The use of two sponges would possibly double the time required to produce the Stern capsule. Additionally, as the sponges would float within the gastric juices, the Reagents would be diluted and possibly affected by the contents of the gastric juices. The Reagents must be placed directly onto the mucosa to allow the urea to migrate to the stomach wall, react with the urease created by the H. pylori , create ammonia, and subsequently alter the pH. To allow for a dilution factor would require increasing the amount of urea used in the capsule. By placing the urea directly onto the mucosa, dilution is reduced to a minimum and therefore a small quantity produces superior accuracy. The beads cannot be coated as commonly known in the time release capsule art, as the reagents on all the beads must be activated simultaneously to obtain a reliable reading. U.S. Pat. No. 3,383,283 to Brindamour discloses time release beads coated with a fatty acid. The fatty acid coating, along with many other coatings, could cause all or some of the beads to float within the gastric juices, again preventing contact with the mucosa.
The disclosed testing procedure is performed in vivo, thereby frequently eliminating the need for a biopsy. In order to view the reagent color change, the beads must remain in a single area. To accomplish this, the beads must not float, but rather lie directly on the mucosa, at the source of the bacteria. It has recently been discovered that H. pylori within the stomach is not continuous or in large areas, but rather patchy areas within the stomach wall. In the instant disclosure, the natural dispersal of the beads onto the mucosa covers a sufficient area to react with at least one area of H. pylori bacteria. Any floating indicators which come in contact with the mucosa on either a temporary or scattered basis, have a narrow chance to come in direct contact with the affected area and would thus produce unreliable results.
Carriers which do not dissolve after a few minutes in the stomach can cause an obstruction of the endoscope if they are below the preferred size. As stated heretofore, other types of dense, vehicles, approved for pharmacological use, can be used as long as they are capable of absorbing the required reagents, have sufficient density to place the capsule, or its contents, onto the mucosa and dissolving within a few minutes. When using a powdered carrier, the reagents are mixed with the carrier, the carrier is allowed to dry, and, if necessary, re-ground to powder form. The beads have the advantage that coating the beads with the reagents is a simpler, more economical method of obtaining optimum results.
An example of manufacture of the beads would be:
Reagent 1
bromothymol blue indicator
buffer (pH=6.0)
sugar beads
Reagent 2
phenol red indicator
buffer (pH=6.0)
sugar beads
urea
The beads are preferably encapsulated into a quick-dissolving gelatin capsule for delivery to the stomach in mass and undiluted. The capsule can be swallowed with a small amount of liquid, such as water, to more rapidly deliver the capsule and speed the dissolving of the capsule. If necessary, a buffer, such as citrate, having a pH between 4.0 and 6.0 can be added to the liquid to render the gastric pH initially slightly acid. Reagents applied in liquid form will mix with each other, even if taken separately, providing an indefinite result.
Additional ingredients can be added with the reagents to produce any specific desired results. An example of this would be to buffer an Acid pH with a stable buffer such as citrate buffer at pH 6.0, 30 mls. The buffer can be added to the seed-coating along with the reagents or can be placed in powdered form in the capsule. The use of a buffer adds stability to the shelf life of the capsules.
In FIG. 1 the stomach wall, bacteria with urease, and mucus layers are shown with the reagent beads resting on the mucus layer. As the urea released from the Reagent 2 comes in contact with the urease, ammonia is generated. The ammonia rises through the mucus layer and comes into contact with the Reagent indicators, causing an increase in the pH and the Reagents to change color.
In order to reduce false readings, the patient should fast overnight prior to the test. This is well known in the prior art and fasting, as well as other known procedures, should be observed prior to conducting the testing procedure disclosed herein.
To administer the test, the subject takes one to two capsules with 30 mls. of pH 6.0 buffer immediately before endoscopy. It takes approximately 5 minutes for the endoscope to reach the stomach, at which time the capsules have dissolved and the granules are resting and slowly dissolving on the surface of the gastric mucosa. Through the endoscope, the examining person can detect the color changes of the reagents, if any, which indicate the presence of the Helicobacter organisms.
In the following example Reagent 2 is yellow at acid pH, changing to red at alkaline pH and Reagent 1 is yellow at acid pH, changing to blue at alkaline pH. The instant invention relies on a differential color change to identify a true positive from a false positive reaction. It is the differential which is of importance, not the colors themselves and any colors and/or reagents specifically used herein are examples and in no way limit the scope of the invention.
READING EXAMPLE I
Negative result, (no urease, stomach is acid)
Reagent 1 (yellow)
Both remain yellow
no urease
Reagent 2 (yellow)
no pH change occurs
READING EXAMPLE II
False positive result (stomach has an alkaline pH; for ex-
ample, bile is in stomach or patient salivates excessively)
Reagent 1 (yellow)
Changes to blue
no urease, pH > 6.5
Reagent 2 (yellow)
Changes to red
READING EXAMPLE III
True positive result (stomach is acid but contains urease)
Reagent 1 (yellow)
urease
Remains yellow
pH < 6
no pH change occurs.
Reagent 2 (yellow)
urease
Changes red
pH rises > 6.5
The presence of red and yellow reagent, but not blue reagent, indicates that urease is in the stomach (i.e. Helicobacter).
A false positive is produced by means of the first indicator indicating an alkaline environment without the influence of the ammonia generated by the urea-urease reaction.
The positive indication is produce by the first indicator showing the presence of an acid environment and the second indicator showing the presence of an alkaline environment. The difference in the reactions to the same environment is due to the presence of the urea in the second indicator. Unlike the first indicator, the second indicator interacts with urease which is present, to generate ammonia.
Thus, where each of the two indicators respond to an acid environment, urease is not present and therefore Helicobacter is not present, since urease would be present if Helicobacter were present.
The negative result is simply due to neither indicator indicating an alkaline condition and consequently indicating an absence of urease generated by Helicobacter.
The unique aspect of the invention is the use of the reagent which is capable of reacting with urease to produce a product which can be readily detected. Urea reacts with urease to release ammonia, which can be detected by pH indicators. Indicators which undergo color changes are well known in the art are commonly used, and can readily be observed though endoscopy.
If the urea were not used, an alkaline environment in the stomach could be mistaken for the presence of Helicobacter. | A method for the in vivo detection of urease-producing Helicobacter in the upper stomach is disclosed. The dense carrier is divided into two separate groups which are combined with separate reagent indicators, one of which also contains urea. The carriers are food soluble products, preferably sugar beads having a diameter of approximately 0.2 to 3.0 mm. The treated carriers and urea are encapsulated in a soluble capsule which is administered to a patient. The density of the carriers cause the capsule to migrate to the gastric mucosa, where the capsule, but not the reagents, is dissolved, placing the reagents and urea in direct contact with the gastric mucosa. The urea reacts with any urease present in the stomach by creating ammonia, which increases the pH in the immediate vicinity of the urea containing carrier and indicator beads. The two reagents react differently, through color change, to the increase in pH, which is viewed through use of an endoscope. A preferred first reagent is bromothymol blue (dibromothymolsulfonphthalein), which changes yellow in the presence of urease, and a preferred second reagent is phenol red (phenolsulfonphthalein), which turns red in the presence of urease. | Briefly describe the main invention outlined in the provided context. | [
"This application is a continuation of Ser.",
"No. 08/489,816 filed Jun. 13, 1995, now abandoned, which is a continuation in part of Ser.",
"No. 08/142,600 filed Oct. 28, 1993, now abandoned, which claims priority to German application 44 20 936.3 filed Jun. 16, 1994.",
"BACKGROUND OF THE INVENTION 1.",
"Brief Description of the Invention The instant invention relates to a novel method of in vivo diagnosis of upper gastrointestinal diseases.",
"Brief Description of the Prior Art Factors adversely affecting the function of the gastrointestinal system in humans are exceedingly varied in their nature.",
"Such disorders may arise in the upper or lower gastrointestinal tracts, or both.",
"There is a broad range of causes of gastrointestinal disorders, including genetic, physiological, environmental and psychogenic factors.",
"Accordingly, the diagnosis and management of these disorders can be exceptionally difficult.",
"Among the chronic disorders of the upper gastrointestinal tract are those which fall under the general categories of gastritis and peptic ulcer disease.",
"The upper gastrointestinal tract is generally defined as including the esophagus, the stomach, the duodenum, the jejunum and ileum.",
"Peptic ulcers are lesions of the gastrointestinal tract lining, characterized by loss of tissue due to the action of digestive acids and pepsin.",
"It has generally been held that peptic ulcers are caused by gastric hypersecretion, decreased resistance of the gastric lining to digestive acids and pepsin, or both.",
"Gastritis is, by definition, an inflammation of the stomach mucosa.",
"In practice, though, the disorder is manifested by a broad range of poorly-defined, and heretofore inadequately treated, symptoms such as indigestion, “heart burn”, dyspepsia, and excessive eructation.",
"As with the management of any disorder, the rapid, precise, and accurate diagnosis of gastrointestinal disorders is of paramount importance.",
"The typical means used to diagnose the gastrointestinal disorder presented by a given patient will depend upon such factors as the nature and severity of symptoms, the overall health of the individual, the medical history of the patient, the need for a specific diagnosis in order to implement a treatment with reasonable likelihood of success, and the availability of diagnostic devices.",
"However, the diagnostic methods typically employed in the art are often slow, cumbersome, costly, and may yield equivocal or inaccurate results.",
"Thus, for patients not having severe symptoms, a precise diagnosis of a gastrointestinal disorder might not be attempted.",
"Such patients may simply be treated with conventional therapies, such as with antacids or drugs which inhibit stomach acid secretion.",
"While such therapies might provide temporary symptomatic relief, a cure is often not effected.",
"More effective treatments may depend upon better diagnoses of the actual underlying gastrointestinal disorder.",
"In particular, it has been discovered that many such gastrointestinal disorders are mediated by infection of gastric mucosa by Helicobacter pylori.",
"H. pylori is a Gram-negative spiral organism which produces the enzyme urease.",
"The organism is predominantly found beneath the mucus layer of the luminal aspect of the gastric epithelium and in the gastric pits.",
"Helicobacter can be diagnosed by blood test for antibodies, breath test, or biopsy of the stomach lining.",
"Antibodies, however, can remain positive for many months after the bacteria have been eradicated.",
"The presence of antibodies presents a falsely positive result in approximately 10 to 15% of patients.",
"Biopsies are relatively quick;",
"however, they add time, expense and risk.",
"Although relatively minor, there is a 1 in 20,000 risk of bleeding from a biopsy site.",
"Biopsies cannot be performed on patients who have a tendency to bleed, such as patients with hemophilia and liver disease.",
"Additionally, it has recently been found that Helicobacter is patchy, thereby requiring multiple biopsies to obtain 100% accuracy.",
"The cost for a biopsy is approximately $100.",
"Biopsies also increase the risk of the person handling the tissue being exposed to HIV.",
"If a urease test is used, the biopsy sample must be placed in the test by the nurse, thereby requiring an additional person during the test.",
"The prior art has disclosed testing for gastrointestinal disorders, the majority of which have been in vitro.",
"Many tests have also been disclosed using urea and indicators.",
"Marshall, 4,748,113 discloses compositions and methods for the diagnosis of gastrointestinal disorders involving urease.",
"Methods include obtaining a gastric sample material and contacting the material with a composition including urease and an indicator.",
"Marshall 4,830,010, discloses methods for the diagnosis of gastrointestinal disorders.",
"The method steps include administration of urea-containing compositions prior to assay.",
"Steward et al, 5,139,934 disclose substrate compositions and method of urease assay.",
"The method is an in vitro immunoassay that includes the use of pH indicators.",
"Nagatsu et al, 4,147,692 disclose methods and compositions for measuring enzymatic activities and correlating such activities with various disease states.",
"Kraffczyk et al, 3,873,369 disclose calorimetric indicators for the determination of urea.",
"Vasquez et al, 4,851,209 disclose in vivo diagnostic procedures for the clinical evaluation of gastrointestinal ulcer disease using radioactive isotopes.",
"Procedures involve prior administration of a diagnostic pharmaceutical followed by scintigraphic imaging of the gastrointestinal area of interest with scintigraphic imaging equipment.",
"Although the use of urease or other indicators has been used in combination with pH indicators, all except Vasquez et al are conducted in vitro.",
"The instant invention discloses a method of detecting the alkaline pH change in vivo.",
"The test dramatically cuts down the number of biopsies required and is safe for patients having any bleeding tendencies while being rapid and low cost.",
"Additionally, through the color change, it can be determined if the change is a true positive or a false positive reaction.",
"BRIEF DESCRIPTION OF THE DRAWINGS The advantages of the instant disclosure will become more apparent when read with the specification and the drawings, wherein: FIG. 1 illustrates the location of the beads in the stomach and the urea/ammonia transfer.",
"SUMMARY OF THE INVENTION A method for the in vivo detection of urease-producing Helicobacter in the upper stomach is disclosed.",
"A dense carrier is used which is divided into two separate groups, the first combined with a first reagent indicator and the second combined with a second reagent indicator and urea.",
"The carriers are food soluble products, preferably sugar beads having a diameter of approximately 0.2 to 3.0 mm.",
"The carrier and reagent can be combined through coating the carrier or combining the carrier and reagent.",
"The treated carriers and urea are encapsulated in a soluble capsule which is administered to a patient.",
"A buffer can be added, if desired, to obtain more specific results.",
"The density of the carriers cause the capsule to descend to the gastric mucosa.",
"The gastric juices dissolve the capsule containing the reagents and urea thereby placing the two reagents and urea combination in direct contact with the gastric mucosa.",
"The urea reacts with any urease present on the mucosa, creating ammonia which causes the pH within the stomach to increase.",
"The two reagents react differently, through color change, to the increase in pH, which is viewed through use of an endoscope.",
"A preferred first reagent is bromothymol blue (dibromothymolsulfonphthalein), which changes yellow in the presence of urease, and a preferred second reagent is phenol red (phenolsulfonphthalein), which turns red in the presence of urease.",
"DETAILED DESCRIPTION OF THE INVENTION The instant disclosure uses indicators to detect pH change, as a result of the presence of H. pylori in the stomach, during endoscopy.",
"A change in the colors of the indicators reflects the pH change within the stomach;",
"a certain combination indicating a pH reaction to the presence of Helicobacter, or H. pylori , organisms.",
"Urea has the formula H 2 NCONH 2 and is a naturally occurring product of protein metabolism.",
"Gastric materials from humans or other animals having gastrointestinal disorders contain relatively large quantities of urease (urea aminohydrolase), which hydrolizes urea to ammonium carbonate or ammonia and carbon dioxide.",
"Normally urease is present in the body in only trace amounts, performing the function of decomposing urea.",
"H. pylori increases the amount of urease above normal in the affected areas.",
"The increased urease reacts with the administered urea by creating ammonia, which causes an indicator color change due to the increased alkalinity.",
"The indicators useful in this invention are weak acids with sharply different colors in their dissociated (ionized) and undissociated (neutral) states.",
"The indicators useful herein are medically approved and have pK a values of from about 6.5 to about 8.5, preferably from about 7.0 to about 8.0.",
"The color exhibited by the indicator in the present composition will depend upon the pH of the composition, the particular indicator used, and the dissociation constant (K a ) for that indicator (i.e., pK a |log 10 K a ).",
"As the color exhibited by the indicator changes over a range of pH values (pH=log 10 [H+]), the indicators useful in the present compositions change color over a pH range of from about 5.5 to about 9.0, preferably from about 6.5 to about 8.5.",
"The pH of the present compositions are accordingly adjusted to a pH at least about one pH unit lower than the pK a of the indicator used (i.e. having a hydrogen ion concentration [H + ] ten times less than (10% of) the hydrogen ion concentration in a solution having a pH equal to the pK a of the indicator).",
"Preferably, the pH is adjusted to a pH about two pH units below the pK a of the indicator.",
"Adjustment of the pH of the present compositions can be effected by addition of a base (e.g. sodium hydroxide) or an acid (e.g. hydrochloric acid or citric acid).",
"Thus, preferably, the pH of the composition of this invention is adjusted to a pH of from about 5.0 to about 6.5, with the preferred embodiment being from about 5.0 to about 6.0.",
"The preferred reagents are bromothymol blue (dibromothymolsulfonphthalein) indicator, Reagent 1, and phenol red (phenolsulfonphthalein) indicator, Reagent 2.",
"Other indicators useful herein include p-nitrophenol, neutral red (2-methyl-3-amino-6-dimethylaminophenazine), quinoline blue (cyanine), cresol red (o-cresolsulfonphthalein), and thymol blue (thymolsulfonphthalein).",
"The reagents used herein must have a pH indicator range which can reflect the range of pH encountered with the the stomach, generally between 5.5 to 9.0.",
"Indicators approved for medical use and useful herein are described in the The Merk Index (9th ed.",
"1976), incorporated by reference herein.",
"Reagents are commonly used in conjunction with biopsies, such as disclosed in U.S. Pat. Nos. 4,748,113 to Marshall and 3,873,269 to Kraffczyk, the disclosures of which are incorporated herein as though recited in full.",
"Reagent 2 has urea added to react with the urease enzyme, if present.",
"The urea penetrates the mucus layer of the stomach to come into contact with the urease-containing bacteria, H. pylori , on the stomach wall.",
"The urea/urease combination creates ammonia which migrates outward through the mucus layer to come into contact with the Reagents.",
"The urea is added to a dense carrier, soluble in gastric juices, at approximately 1-20 grams per kilogram of carrier.",
"The preferred carrier is beads, such as nu-pareil beads, although any carrier approved for pharmacological use can be used which has sufficient density to deposit the capsule to the stomach mucosa.",
"The density of the carrier is critical in that it must be able to migrate, or descend to the gastric mucosa, therefore requiring a density, or weight, greater than that of the body fluids.",
"Appropriate dense carriers for use in the medical arts will be readily known to those skilled in the art.",
"It is preferred that the carrier have a neutral pH to prevent interference with the test results.",
"In the event that the carrier has a non-neutral pH, acidic or alkaline ingredients should be incorporated within the capsule to compensate for the carrier's pH.",
"In the preferred embodiment the Reagents 1 and 2 are put into the stomach in a solid phase, such as beads, which can be individually identified in the stomach.",
"The reagents should be coated onto small diameter beads, preferably 0.2-3.0 mm, with the preferred size being approximately 2 mm.",
"The 2 mm.",
"bead size provides the advantages of visibility as well as preventing obstruction of the endoscope in the event not all of the beads dissolve.",
"A suitable method of making such beads would be to use sugar beads, such as nu-pareil seeds, with a mesh size of 25-35.",
"The nu-pareil beads provide the density required to migrate to the mucosa, either in the capsule or after the capsule dissolves.",
"A less dense vehicle, which floats within the gastric juices, would prevent the Reagents from being placed onto the mucosa.",
"The choice of the carrier is contrasted with those in the Stern and Brindamour patents wherein the carriers float within the gastric juices.",
"U.S. Pat. No. 3,121,041, issued to Stern et al, discloses the use of a plug, impregnated with a radioactive material, in combination with a soluble capsule.",
"The spongy plug disclosed in Stern would float within the gastric juices, providing several disadvantages.",
"In order to obtain the contrasting results of the two reagents, two impregnated sponges must be used within the capsule, thereby increasing manufacturing expenses.",
"The Stern et al patent discloses tapping the sponges into the capsule.",
"The use of two sponges would possibly double the time required to produce the Stern capsule.",
"Additionally, as the sponges would float within the gastric juices, the Reagents would be diluted and possibly affected by the contents of the gastric juices.",
"The Reagents must be placed directly onto the mucosa to allow the urea to migrate to the stomach wall, react with the urease created by the H. pylori , create ammonia, and subsequently alter the pH.",
"To allow for a dilution factor would require increasing the amount of urea used in the capsule.",
"By placing the urea directly onto the mucosa, dilution is reduced to a minimum and therefore a small quantity produces superior accuracy.",
"The beads cannot be coated as commonly known in the time release capsule art, as the reagents on all the beads must be activated simultaneously to obtain a reliable reading.",
"U.S. Pat. No. 3,383,283 to Brindamour discloses time release beads coated with a fatty acid.",
"The fatty acid coating, along with many other coatings, could cause all or some of the beads to float within the gastric juices, again preventing contact with the mucosa.",
"The disclosed testing procedure is performed in vivo, thereby frequently eliminating the need for a biopsy.",
"In order to view the reagent color change, the beads must remain in a single area.",
"To accomplish this, the beads must not float, but rather lie directly on the mucosa, at the source of the bacteria.",
"It has recently been discovered that H. pylori within the stomach is not continuous or in large areas, but rather patchy areas within the stomach wall.",
"In the instant disclosure, the natural dispersal of the beads onto the mucosa covers a sufficient area to react with at least one area of H. pylori bacteria.",
"Any floating indicators which come in contact with the mucosa on either a temporary or scattered basis, have a narrow chance to come in direct contact with the affected area and would thus produce unreliable results.",
"Carriers which do not dissolve after a few minutes in the stomach can cause an obstruction of the endoscope if they are below the preferred size.",
"As stated heretofore, other types of dense, vehicles, approved for pharmacological use, can be used as long as they are capable of absorbing the required reagents, have sufficient density to place the capsule, or its contents, onto the mucosa and dissolving within a few minutes.",
"When using a powdered carrier, the reagents are mixed with the carrier, the carrier is allowed to dry, and, if necessary, re-ground to powder form.",
"The beads have the advantage that coating the beads with the reagents is a simpler, more economical method of obtaining optimum results.",
"An example of manufacture of the beads would be: Reagent 1 bromothymol blue indicator buffer (pH=6.0) sugar beads Reagent 2 phenol red indicator buffer (pH=6.0) sugar beads urea The beads are preferably encapsulated into a quick-dissolving gelatin capsule for delivery to the stomach in mass and undiluted.",
"The capsule can be swallowed with a small amount of liquid, such as water, to more rapidly deliver the capsule and speed the dissolving of the capsule.",
"If necessary, a buffer, such as citrate, having a pH between 4.0 and 6.0 can be added to the liquid to render the gastric pH initially slightly acid.",
"Reagents applied in liquid form will mix with each other, even if taken separately, providing an indefinite result.",
"Additional ingredients can be added with the reagents to produce any specific desired results.",
"An example of this would be to buffer an Acid pH with a stable buffer such as citrate buffer at pH 6.0, 30 mls.",
"The buffer can be added to the seed-coating along with the reagents or can be placed in powdered form in the capsule.",
"The use of a buffer adds stability to the shelf life of the capsules.",
"In FIG. 1 the stomach wall, bacteria with urease, and mucus layers are shown with the reagent beads resting on the mucus layer.",
"As the urea released from the Reagent 2 comes in contact with the urease, ammonia is generated.",
"The ammonia rises through the mucus layer and comes into contact with the Reagent indicators, causing an increase in the pH and the Reagents to change color.",
"In order to reduce false readings, the patient should fast overnight prior to the test.",
"This is well known in the prior art and fasting, as well as other known procedures, should be observed prior to conducting the testing procedure disclosed herein.",
"To administer the test, the subject takes one to two capsules with 30 mls.",
"of pH 6.0 buffer immediately before endoscopy.",
"It takes approximately 5 minutes for the endoscope to reach the stomach, at which time the capsules have dissolved and the granules are resting and slowly dissolving on the surface of the gastric mucosa.",
"Through the endoscope, the examining person can detect the color changes of the reagents, if any, which indicate the presence of the Helicobacter organisms.",
"In the following example Reagent 2 is yellow at acid pH, changing to red at alkaline pH and Reagent 1 is yellow at acid pH, changing to blue at alkaline pH.",
"The instant invention relies on a differential color change to identify a true positive from a false positive reaction.",
"It is the differential which is of importance, not the colors themselves and any colors and/or reagents specifically used herein are examples and in no way limit the scope of the invention.",
"READING EXAMPLE I Negative result, (no urease, stomach is acid) Reagent 1 (yellow) Both remain yellow no urease Reagent 2 (yellow) no pH change occurs READING EXAMPLE II False positive result (stomach has an alkaline pH;",
"for ex- ample, bile is in stomach or patient salivates excessively) Reagent 1 (yellow) Changes to blue no urease, pH >",
"6.5 Reagent 2 (yellow) Changes to red READING EXAMPLE III True positive result (stomach is acid but contains urease) Reagent 1 (yellow) urease Remains yellow pH <",
"6 no pH change occurs.",
"Reagent 2 (yellow) urease Changes red pH rises >",
"6.5 The presence of red and yellow reagent, but not blue reagent, indicates that urease is in the stomach (i.e. Helicobacter).",
"A false positive is produced by means of the first indicator indicating an alkaline environment without the influence of the ammonia generated by the urea-urease reaction.",
"The positive indication is produce by the first indicator showing the presence of an acid environment and the second indicator showing the presence of an alkaline environment.",
"The difference in the reactions to the same environment is due to the presence of the urea in the second indicator.",
"Unlike the first indicator, the second indicator interacts with urease which is present, to generate ammonia.",
"Thus, where each of the two indicators respond to an acid environment, urease is not present and therefore Helicobacter is not present, since urease would be present if Helicobacter were present.",
"The negative result is simply due to neither indicator indicating an alkaline condition and consequently indicating an absence of urease generated by Helicobacter.",
"The unique aspect of the invention is the use of the reagent which is capable of reacting with urease to produce a product which can be readily detected.",
"Urea reacts with urease to release ammonia, which can be detected by pH indicators.",
"Indicators which undergo color changes are well known in the art are commonly used, and can readily be observed though endoscopy.",
"If the urea were not used, an alkaline environment in the stomach could be mistaken for the presence of Helicobacter."
] |
BACKGROUND OF THE INVENTION
The present invention relates generally to tools used to complete subterranean wells and, in a preferred embodiment thereof, more particularly provides apparatus for use in gravel pack operations and methods of using same.
Gravel pack operations are typically performed in subterranean wells to prevent fine particles of sand or other debris from being produced along with valuable fluids extracted from a geological formation. If produced (i.e., brought to the earth's surface), the fine sand tends to erode production equipment, clog filters, and present disposal problems. It is, therefore, economically and environmentally advantageous to ensure that the fine sand is not produced.
In the subterranean well, a tubular protective casing usually separates the formation containing the fine sand particles from the wellbore. The casing is typically perforated opposite the formation to provide flowpaths for the valuable fluids from the formation to the wellbore. If production tubing is simply lowered into the wellbore and the fluids are allowed to flow directly from the formation, into the wellbore, and through the production tubing to the earth's surface, the fine sand will be swept along with the fluids and will be carried to the surface by the fluids.
Conventional gravel pack operations prevent the fine sand from being swept into the production tubing by installing a sand screen on the end of the production tubing. The wellbore in an annular area between the screen and the casing is then filled with a relatively large grain sand (i.e., "gravel"). The gravel prevents the fine sand from packing off around the production tubing and screen, and the screen prevents the large grain sand from entering the production tubing.
A problem, which is present in every conventional gravel pack operation, is how to place the gravel in the annular area between the screen and the casing opposite the formation. If the screen is merely attached to the bottom of the production tubing when it is installed in the wellbore, the gravel cannot be pumped down the production tubing because the screen will prevent it from exiting the tubing. The gravel cannot be dropped into the wellbore annular area from the earth's surface because a packer is usually installed between the production tubing and the casing above the formation, and this method would be very inaccurate in packerless completions as well.
One solution has been to run the production tubing into the wellbore without the screen being attached to the tubing. A landing nipple is installed at or near the bottom of the tubing before running the tubing into the well. When the landing nipple has been properly positioned above the formation, a screen is lowered into the tubing from the earth's surface on a slickline or wireline. The screen is landed in the nipple in the tubing so that it extends outwardly and downwardly from the tubing and is positioned opposite the formation. Gravel is then pumped down the tubing from the earth's surface, through a small space between the nipple and the screen, and outwardly into the annular area between the screen and the casing opposite the formation. This method is known as "through tubing gravel packing", since the gravel is pumped through the tubing.
This method has several disadvantages, however. One disadvantage is that the screen must be installed into the tubing as a separate operation. This requires coordination with a slickline or wireline service, time spent rigging up and rigging down special equipment such as lubricators needed for these operations, and the inability to conveniently perform such operations in wells which are horizontal or nearly horizontal. In some instances, the screen is run in with the tubing, already landed in the nipple in the tubing. In those instances, a slickline operation is still needed to retrieve the screen from the tubing.
Another disadvantage of the above method is that the screen must be able to pass through the tubing. This means that the size of the screen (at least its outer diameter) can be no larger than the tubing's inner drift diameter. In order to have a sufficiently large screen surface area, very long screens must sometimes be utilized with this method. Additionally, since there is usually only a very small radial gap between the screen (or the slickline tool used to place the screen in the nipple) and the landing nipple, only a very small flow area is available for pumping the gravel out of the tubing and into the annular area of the well.
Yet another disadvantage of the above method is that the tubing may not be conveniently removed from the wellbore for replacing the packer, completing other formations in the well, maintenance, etc. The method requires the screen to be removed along with the tubing, or the screen must be removed by wireline or slickline prior to removing the tubing. In either case, the gravel pack will be destroyed as the gravel falls into the void created when the screen is removed.
From the foregoing, it can be seen that it would be quite desirable to provide apparatus for gravel pack operations which does not require the screen to be positioned as a separate operation and does not require the screen to pass through the tubing, but which provides a large flow area for pumping the gravel into the annular area of the well and provides for convenient detachment of the tubing from the screen for removal of the tubing from the wellbore. It is accordingly an object of the present invention to provide such apparatus and associated methods of using same.
SUMMARY OF THE INVENTION
In carrying out the principles of the present invention, in accordance with an embodiment thereof, gravel pack apparatus is provided which is a unique valve and release mechanism. The valve permits pumping gravel therethrough with the screen attached to the bottom of the tubing, and the release mechanism permits convenient detachment of the tubing from the screen.
In broad terms, apparatus is provided which includes tubular first and second housings, a ball seat, a plurality of collets, a flow passage and a tubular sleeve. The second housing is coaxially disposed relative to the first housing, with an end of the first housing being proximate an end of the second housing. The flow passage extends through the first and second housings.
The collets extend axially between the first housing and the second housing and releasably secure the first housing against axial displacement relative to the second housing. The tubular sleeve is coaxially disposed within the first and second housings and has an outer diameter radially inwardly adjacent the collets. The sleeve outer diameter radially outwardly biases the collets, and the sleeve is disposed adjacent the ball seat, such that the sleeve is capable of axial movement relative to the collets when a pressure differential is created across the ball seat.
Additionally, apparatus is provided which includes tubular first and second housings, a ball seat, a lug, a flow passage, and a tubular sleeve. The flow passage extends through the first and second housings.
The first housing has an end portion and a radially extending opening formed through the end portion. The second housing has an end portion radially outwardly and coaxially disposed relative to the first housing end portion.
The lug extends radially through the opening and between the first housing end portion and the second housing end portion. The lug releasably secures the first housing against axial displacement relative to the second housing.
The tubular sleeve is coaxially disposed within the first housing. It has an outer diameter radially inwardly adjacent the lug which radially outwardly biases the lug. The sleeve is disposed adjacent the ball seat, such that the sleeve is capable of axial movement relative to the lug when a pressure differential is created across the ball seat.
A method of completing a subterranean well having a wellbore intersecting a formation is also provided, which method includes the steps of providing a gravel pack device, providing production tubing, attaching the gravel pack device to the production tubing, and inserting the gravel pack device and production tubing into the wellbore.
The gravel pack device includes first and second tubular housings, a collet member releasably securing the first tubular housing in a coaxial and adjoining relationship with the second tubular housing, an expandable circumferential seal surface, an internal flow passage extending axially through the seal surface and the first housing, and a tubular sleeve having an outer side surface. The tubular sleeve has a first position, in which the sleeve outer side surface radially biases the collet member to secure the first and second housings against axial displacement therebetween, and a second position, axially displaced relative to the collet member from the first position, in which the sleeve outer side surface unbiases the collet member to release the first and second housings for axial displacement therebetween.
The seal surface is capable of biasing the sleeve to axially displace from the first position to the second position when a pressure differential is created across the seal surface. The method also includes the steps of creating the pressure differential across the seal surface and releasing the first and second housings for axial displacement therebetween.
Additionally, a method of gravel packing a formation intersected by a subterranean wellbore is also provided. The method includes the steps of providing a device, production tubing, and a sand control screen, attaching the device between the tubing and the sand control screen, and inserting the tubing, device, and sand control screen into the wellbore.
The device includes first and second tubular housings, a ball seat, collets, a flow passage, a plug releasably secured in the flow passage, a flow port, and a tubular sleeve. The second housing is coaxially disposed relative to the first housing with an end of the first housing being proximate an end of the second housing. The ball seat is coaxially disposed within the first housing. The flow port is capable of permitting fluid communication between the flow passage and the wellbore.
The collets extend axially between the first housing end and the second housing end and releasably secure the first housing against axial displacement relative to the second housing. The sleeve is coaxially disposed within the first and second housings and has an outer diameter radially inwardly adjacent the collets. The sleeve outer diameter radially outwardly biases the collets, and the sleeve is disposed adjacent the ball seat, such that the sleeve is capable of axial movement relative to the flow port and the collets when a first predetermined pressure differential is created across the ball seat. The plug is capable of being expelled from the flow passage when a second predetermined pressure differential is created across the plug.
The method further includes the steps of positioning the sand control screen in a predetermined axial position in the wellbore relative to the formation and forcing a gravel pack slurry through the production tubing, into the flow passage, through the flow port, into the wellbore, and into an annular area radially intermediate the sand control screen and the formation. The first predetermined pressure differential is created across the ball seat by sealingly engaging a ball with the ball seat and applying pressure to the production tubing. The second predetermined pressure differential is created across the plug by applying pressure to the production tubing after the first predetermined pressure differential is created.
The use of the disclosed apparatus and methods of using same permits larger screens to be used in through-tubing gravel pack operations, provides larger flow areas through which to pump the gravel, eliminates separate screen installation and removal by wireline or slickline operations, and permits convenient removal of the tubing while the screen and gravel pack remain undisturbed in the well.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1B are cross-sectional views of a first apparatus embodying principles of the present invention;
FIGS. 2A-2B are highly schematicized cross-sectional views of a method embodying principles of the present invention, using the first apparatus;
FIGS. 3A-3B are cross-sectional views of a second apparatus embodying principles of the present invention;
FIGS. 4A-4B are cross-sectional views of a third apparatus embodying principles of the present invention;
FIGS. 5A-5C are cross-sectional views of a fourth apparatus embodying principles of the present invention; and
FIGS. 6A-6B are cross-sectional views of a sixth apparatus embodying principles of the present invention.
DETAILED DESCRIPTION
The following descriptions of preferred embodiments of the present invention describe use of the embodiments in gravel packing operations in subterranean wellbores. It is to be understood, however, that apparatus and methods embodying principles of the present invention may be utilized in other operations, such as fracturing or acidizing operations.
Illustrated in FIGS. 1A and 1B is a gravel pack apparatus 10 which embodies principles of the present invention. In the following detailed description of the apparatus 10 representatively illustrated in FIGS. 1A and 1B, and subsequent apparatus, methods, and figures described hereinbelow, directional terms such as "upper", "lower", "upward", "downward", etc. will be used in relation to the apparatus 10 as it is depicted in the accompanying figures. It is to be understood that the apparatus 10 and subsequent apparatus and methods described hereinbelow may be utilized in vertical, horizontal, inverted, or inclined orientations without deviating from the principles of the present invention.
The apparatus 10 includes a tubular upper housing 12, a tubular lower housing 14, an expandable ball seat 16, a plug 18, collets 20, and a tubular sleeve 22. FIG. 1A shows the apparatus 10 in a configuration in which it is run into the wellbore prior to the gravel pack operation. FIG. 1B shows the apparatus 10 in a configuration subsequent to the gravel pack operation. Comparing FIG. 1B to FIG. 1A, note that the expandable ball seat 16 has expanded radially outward within the upper housing 12, the sleeve 22 has been shifted downward within the upper housing, the plug 18 has been ejected out of the sleeve, and the lower housing 14 has separated from the upper housing 12.
When initially run into the wellbore prior to the gravel pack operation, as shown in FIG. 1A, the apparatus 10 is installed between the production tubing and the sand control screen (not shown in FIGS. 1A and 1B). The tubing is threadedly and sealingly attached to the upper housing 12 at upper connector 24. An interior axial flow passage 26 is thus placed in fluid communication with the interior of the production tubing. The screen is threadedly and sealingly attached to the lower housing 14 at lower end 28. Plug 18 in sleeve 22 prevents fluid communication between the interior of the production tubing and the interior of the screen via the flow passage 26.
Plug 18 prevents gravel, pumped down the tubing from the earth's surface, from filling the interior of the sand screen during the gravel pack operation. The plug 18 is later ejected, as shown in FIG. 1B, to permit flow of fluids from the interior of the screen, through the flow passage 26, and into the production tubing for transport to the earth's surface. A circumferential seal 34 sealingly engages the plug 18 and sleeve 22 and permits a pressure differential to be created across the plug to shear shear pins 36 which extend radially through the sleeve 22 and into the plug.
Radially extending ports 30 on the sleeve 22 are initially aligned with radially extending ports 32 on the upper housing 12, permitting fluid communication between the flow passage 26 and the wellbore external to the apparatus 10. During the gravel pack operation, gravel may be pumped through the ports 30 and 32 and into the annular area between the screen and the casing. Radially extending and circumferentially spaced splines 33 formed on lower housing 14 permit fluid flow longitudinally between the wellbore external to the upper housing 12 and the wellbore below the lower housing as further described below.
The aligned relationship of the ports 30 and 32 is releasably secured by shear pins 38 threadedly installed radially through the upper housing 12 and into the sleeve 22. When shear pins 38 are sheared, sleeve 22 is permitted to move downwardly until radially sloping shoulder 40 on the sleeve 22 contacts radially sloping shoulder 42 on the upper housing 12.
When sleeve 22 has been downwardly shifted, as shown in FIG. 1B, circumferential seals 44, which sealingly engage the sleeve and upper housing 12, straddle the ports 32 on the upper housing 12 and prevent fluid communication between the flow passage 26 and the wellbore external to the apparatus 10. Circumferential seals 46, 48, and 50 sealingly engage the upper connector 24 and an upper end 52 of the upper housing 12, the sleeve 22 and the upper housing, and the sleeve and the lower housing 14, respectively, also preventing fluid communication between the flow passage 26 and the wellbore external to the apparatus 10.
Sleeve 22 is downwardly shifted within the upper housing 12 by the expandable ball seat 16. The expandable ball seat 16 is of conventional construction and is in a radially compressed configuration, as viewed in FIG. 1A, when installed into the upper connector 24. Upwardly facing seal surface 54 on the ball seat 16, when in the radially compressed configuration, is smaller in diameter than, and is thus capable of sealingly engaging, a ball 56 dropped or pumped down through the production tubing. It is to be understood that the ball 56 would preferably not be dropped through the production tubing during the gravel pack operation as it would interfere with the pumping of gravel through the apparatus 10. The ball 56 is preferably dropped through the production tubing when the gravel pack operation has been completed and it is desired to shift the sleeve 22 to close ports 32.
When the ball 56 sealingly engages the seal surface 54, a pressure differential may be created across the ball seat 16 by applying pressure to the interior of the production tubing at the earth's surface. Such a pressure differential downwardly biases the ball seat 16 against the sleeve 22, forcing radially sloping surface 57 on the ball seat 16 against radially sloping surface 58 on the sleeve. The contact between the sloping surfaces 57 and 58 further biases the ball seat 16 radially outward.
When sufficient pressure differential has been created across the ball seat 16, shear pins 38 shear, permitting the sleeve 22 to downwardly shift, as described above, and permitting the ball seat 16 to expand radially outward into radially enlarged inner diameter 60 within the upper housing 12. Such expansion of the ball seat 16 causes the seal surface 54 to have an inner diameter larger than that of the ball 56, which permits the ball to pass through the ball seat and the flow passage 26 to the plug 18. Thus, when the plug 18 is later expelled from the sleeve 22, as shown in FIG. 1B and described above, the ball 56 will also be expelled.
Lower housing 14 is initially coaxially attached to the upper housing 12, as shown in FIG. 1A, with collets 20 which are threadedly installed onto the upper housing. Radially enlarged outer diameter 62 on the sleeve 22 biases the collets 20 radially outward so that radially extending projections 64 on the collets are radially larger than reduced inner diameter 66 on the lower housing 14. When, however, the sleeve 22 has been downwardly shifted, as shown in FIG. 1B, the collets 20 are no longer radially outwardly biased by diameter 62 on the sleeve, and the collets are permitted to flex radially inward. Inner diameter 66 on the lower housing 14 may then pass over the projections 64, permitting the lower housing to separate from the upper housing 12.
In a preferred mode of operation, the apparatus 10 is installed between the production tubing and the sand control screen as described above. During the gravel pack operation, gravel is pumped down through the tubing and into flow passage 26. The gravel exits through the aligned ports 30 and 32 and flows into the wellbore. When the gravel pack operation is completed, the ball 56 is dropped or pumped down through the tubing to the ball seat 16. Pressure is applied to the tubing at the surface until a first predetermined pressure differential is created across the ball seat 16, shearing the shear pins 38 and forcing the sleeve 22 to shift downward. At this point, ports 32 are closed, preventing fluid communication between the wellbore and the flow passage 26, and collets 20 are no longer biased radially outward. The ball 56 passes through the ball seat 16. A second predetermined pressure differential is then created across the plug 18 by applying pressure to the tubing at the earth's surface, thereby shearing shear pins 36, and expelling the plug 18 and the ball 56 from the sleeve 22. The tubing may be removed from the wellbore when desired, without displacing or otherwise disturbing the screen or gravel pack.
Turning now to FIGS. 2A and 2B, a method 70 of using the apparatus 10 is representatively illustrated. It is to be understood that, with suitable modifications, other apparatus may be utilized in method 70, including other apparatus described hereinbelow, without departing from the principles of the present invention.
FIG. 2A shows the apparatus 10 operatively installed between production tubing 72, which extends to the earth's surface and is attached to the upper housing 12, and sand control screen 74. The screen 74, apparatus 10, and tubing 72 are lowered into wellbore 76, which intersects formation 78 and is lined with protective casing 80. A conventional tubing hanger 82 has previously been set in the casing 80 a predetermined distance above the formation 78. As the screen 74, apparatus 10, and tubing 72 are lowered into the wellbore, splines 33 on the lower housing 14 engage the tubing hanger 82, thereby positioning the screen 74 in the wellbore 76 opposite the formation 78. Alternatively, splines 33 could engage, for example, a nipple (not shown) disposed in a string of production tubing (not shown), or the nipple could be suspended from a packer (not shown) set in the casing 80.
A gravel pack slurry 84 is then pumped down the tubing 72 from the earth's surface. The slurry 84 enters the flow passage 26 of the apparatus 10 and then exits the apparatus through open ports 32. The slurry 84 then flows downwardly in the wellbore 76 and passes between the splines 33 and the tubing hanger 82. From the tubing hanger 82, the slurry 84 enters an annular area 86 below the tubing hanger and radially intermediate the screen 74 and the casing 80.
Slurry 84 is pumped into the annular area 86 until it forms a gravel pack 88 as shown in FIG. 2B. The ball 56 is then dropped or pumped down the tubing 72, the ball sealingly contacting the ball seat 16. Pressure is applied to the tubing 72 to shift the sleeve 22 downward and close ports 32 as described above. The collets 20 are also no longer biased radially outward after the sleeve 22 is downwardly shifted, but the upper housing 12 is not yet separated from the lower housing 14.
Pressure is again applied to the tubing 72 to expel the plug 18 and ball 56 from the sleeve 22 as described above. The plug 18 and ball 56 then drop into the screen 74 as shown in FIG. 2B. At this point the tubing 72 is in fluid communication with the screen 74 and fluids 90 may flow from the formation 78, through the gravel pack 88 in the annular area 86, through the screen 74, through the flow passage 26 of the apparatus 10, and upwardly through the tubing 72 to the earth's surface.
If desired, the tubing 72 may be conveniently removed from the wellbore 76 by raising the tubing to separate the upper housing 12 from the lower housing 14. The lower housing 14 remains in the wellbore 76, supporting the screen 74 opposite the formation 78 in the gravel pack 88 as shown in FIG. 2B. The screen 74 and gravel pack 88 are not disturbed when the tubing 72 is removed from the wellbore 76.
Note that, in the above-described method 70, screen 74 is not required to pass through the tubing 72 and, therefore, has an outer diameter which is limited only by the casing 80 or tubing hanger 82. Note also, that a relatively large flow area is available for slurry 84 to flow between the lower housing 14 and the tubing hanger 82 via the splines 33. Additionally, no separate wireline or slickline operation is needed in method 70 to position or remove the screen 74.
Turning now to FIGS. 3A and 3B, an apparatus 10a is shown which is a modified form of the apparatus 10 shown in FIGS. 1A-2B. Elements of apparatus 10a which are similar to those elements previously described are indicated in FIGS. 3A and 3B with the same reference numerals, but with an added suffix "a".
Apparatus 10a functions similar to apparatus 10, the major difference being that ports 32a are initially closed, as shown in FIG. 3A. Ports 32a are axially displaced from ports 94 on sleeve 96. Circumferential seal 98 sealingly engages the sleeve 96 and upper housing 12a and is disposed axially intermediate ports 94 and 32a, thereby preventing fluid communication between the ports.
When the sleeve 96 is downwardly shifted, as shown in FIG. 3B, ports 94 and 32a are aligned and fluid communication is established between the flow passage 26a and the wellbore external to the apparatus 10a. It will be readily appreciated by one skilled in the art that if the flow passage 26a is in fluid communication with the wellbore and the interior of lower end 28a is in fluid communication with the wellbore, a pressure differential cannot be created across the plug 18a to expel the plug and ball 56a from the sleeve 96. Thus, if the plug 18a is desired to be expelled from the sleeve 96 of apparatus 10a by pressure differential created across the plug, a means, such as gravel pack 88 (see FIG. 2B), to restrict fluid communication between the flow passage 26a and the interior of the lower end 28a via the wellbore must be utilized.
Thus, apparatus 10a is useful in circumstances in which it is desired to run the apparatus into the wellbore with ports 32a initially closed. The ports 32a may then be opened by dropping or pumping ball 56a down the tubing and applying a predetermined pressure to shear shear pins 38a and downwardly shift the sleeve 96.
When sleeve 96 has been shifted downward, ports 32a and 94 are aligned and permit flow therethrough, and collets 20a are no longer radially outwardly biased by enlarged outer diameter 62a. The upper housing 12a may then be separated from lower housing 14a, and, if a means to seal flow passage 26a against fluid communication with lower end 28a has been utilized, the ball 56a and plug 18a may be expelled from the sleeve 96 by applying a second pressure differential to shear shear pins 36a.
Illustrated in FIGS. 4A and 4B is an apparatus 10b which is another modified form of the apparatus 10 shown in FIGS. 1A-2B. Elements of apparatus 10b which are similar to those elements previously described are indicated in FIGS. 4A and 4B with the same reference numerals, but with an added suffix "b".
Apparatus 10b functions similar to apparatus 10, the major difference being that there are no ports 30 and 32 and no plug 18. The flow passage 26b extends axially through the apparatus 10b, permitting flow therethrough at all times, except for when ball 56b is dropped or pumped down to ball seat 16b and engages seal surface 54b. Circumferential seal 102 sealingly engages sleeve 100 and upper housing 12b and is disposed axially intermediate shear pins 38b and upper connector 24b.
The sleeve 100 is shifted downward by pumping or dropping ball 56b into the apparatus lob so that the ball 56b sealingly engages the ball seat 16b. A predetermined pressure is created across the ball seat 16b, shearing shear pins 38b. The ball seat 16b then expands radially outward and ball 56b is permitted to pass through flow passage 26b.
When sleeve 100 is downwardly shifted, as shown in FIG. 4B, collets 20b are no longer radially outwardly biased by enlarged outer diameter 62b. The upper housing 12b may then be separated from lower housing 14b. Thus, apparatus 10b is useful in circumstances in which it is desired to run the apparatus into the wellbore with no fluid communication between the flow passage 26b and the wellbore external to the apparatus 10b, or when such fluid communication is otherwise provided, and then to separate the upper housing 12b from the lower housing 14b.
FIGS. 5A-5C show an apparatus 10c which is yet another modified form of the apparatus 10 shown in FIGS. 1A-2B. Elements of apparatus 10c which are similar to those elements previously described are indicated in FIGS. 5A-5C with the same reference numerals, but with an added suffix "c".
Apparatus 10c functions similar to apparatus 10, the major difference being the inclusion of annular ring 106 in annular space 108 axially intermediate sloping surfaces 40c and 42c, and radially intermediate the sleeve 22c and upper housing 12c. Annular ring 106 has upper and lower radially sloping surfaces 110 and 112, respectively, and is releasably secured by shear pins 114 against axial movement relative to the upper housing 12c. As will be readily appreciated by consideration of the following description, annular ring 106 permits the steps of closing the ports 32c and separating the housings 12c and 14c to be performed separately.
When the sleeve 22c is downwardly shifted, as shown in FIG. 5B, ports 32c are closed, preventing fluid communication between the flow passage 26c and the wellbore external to the apparatus 10c. In this configuration of the apparatus 10c, sloping shoulder 40c on sleeve 22c is in contact with sloping shoulder 110 of annular ring 106. The ball seat 16c is expanded radially outward, permitting the ball 56c to pass through the flow passage 26c. Plug 18c and ball 56c may be expelled from the sleeve 22c by creating a sufficient differential pressure across the plug to shear shear pins 36c. However, unlike apparatus 10 as shown in FIG. 1B, the upper housing 12c may not be separated from the lower housing 14c with the apparatus 10c in the configuration shown in FIG. 5B, because the collets 20c remain radially outwardly biased by outer diameter 62c on the sleeve 22c.
In order to separate upper housing 12c from lower housing 14c, a second ball 116 is dropped or pumped down into the apparatus 10c. The ball 116 has a larger diameter than the first ball 56c, but is still able to pass through the expanded ball seat 16c as shown in FIG. 5C. The ball 116 has a diameter which is, however, too large to pass through the sleeve 22c. Instead, the ball 116 sealingly engages a circumferential seal surface 118 on the sleeve 22c, disposed adjacent the sloping surface 58c. A pressure differential may now be created across the ball 116 to downwardly bias the sleeve 22c and shear shear pins 114. The sleeve 22c and annular ring 106 may then shift downwardly until sloping shoulder 112 contacts sloping shoulder 42c. When the sleeve 22c is thus further shifted downwardly, outer diameter 62c no longer radially outwardly biases the collets 20c and the upper housing 12c may be separated from the lower housing 14c. Additionally, ports 32c are again opened, permitting fluid communication between the wellbore and the apparatus 10c interior above the ball 116.
In a preferred mode of operation, the apparatus 10c is installed between the production tubing and the sand control screen as described above. During the gravel pack operation, gravel is pumped down through the tubing and into flow passage 26c. The gravel exits through the aligned ports 30c and 32c and flows into the wellbore. When the gravel pack operation is completed, the ball 56c is dropped or pumped down through the tubing to the ball seat 16c. Pressure is applied to the tubing at the surface until a first predetermined pressure differential is created across the ball seat 16c, shearing the shear pins 38c and forcing the sleeve 22c to shift downward. At this point, ports 32c are closed, preventing fluid communication between the wellbore and the flow passage 26c. The ball 56c passes through the ball seat 16c. A second predetermined pressure differential is then created across the plug 18c by applying pressure to the tubing at the earth's surface, thereby shearing shear pins 36c, and expelling the plug 18c and the ball 56c from the sleeve 22c. The well may then go into production, with fluids flowing from the formation, through the gravel pack, through the screen, and upwardly through the flow passage 26c and the tubing to the earth's surface. If it is later desired to remove the tubing from the wellbore without displacing or otherwise disturbing the screen and gravel pack, a second ball 116 is dropped or pumped down the tubing and a third predetermined pressure differential is created across the ball to shear shear pins 114. The sleeve 22c then shifts further downwardly, permitting the collets 20c to flex radially inward. The tubing may then be removed from the wellbore, any fluid remaining in the tubing being able to flow out of the re-opened ports 32c into the wellbore during the tubing's removal.
Thus, apparatus 10c is useful in circumstances in which it is desired to run the apparatus into the wellbore with ports 32c initially open, perform the gravel pack operation, close the ports, and expel the plug 18c and ball 56c before putting the well into production, but it is not desired to concurrently release the upper housing 12c for separation from the lower housing 14c. This permits the tubing, apparatus 10c, and screen to later be removed from the wellbore together (the upper and lower housings 12c and 14c, respectively, remaining attached), or, if it is desired to remove the tubing, but not the screen, from the wellbore, the second ball 116 may be dropped or pumped down through the tubing to separate the upper and lower housings 12c and 14c, respectively.
FIGS. 6A and 6B show another apparatus 124 embodying principles of the present invention. The apparatus 124 includes an upper housing 126, a lower housing 128, an expandable ball seat 130, a plug 132, collets or lugs 134, and a sleeve 136. FIG. 6A shows the apparatus 124 in a configuration in which it is run into the wellbore prior to the gravel pack operation. FIG. 6B shows the apparatus 124 in a configuration subsequent to the gravel pack operation. Comparing FIG. 6B to FIG. 6A, note that the expandable ball seat 130 has expanded radially outward within the lower housing 128, the sleeve 136 has been shifted downward within the lower housing, the plug 132 has been ejected, and the lower housing 128 has separated from the upper housing 126.
When initially run into the wellbore prior to the gravel pack operation, as shown in FIG. 6A, the apparatus 124 is installed between the production tubing and the sand control screen. The tubing is threadedly and sealingly attached to the upper housing 126 threaded connection 137. An interior axial flow passage 138 is thus placed in fluid communication with the interior of the production tubing. The screen is threadedly and sealingly attached to the lower housing 128 at threaded connection 140. Plug 132 is retained in an annular sleeve 142 disposed in an inner diameter 144 of lower housing 128 and prevents fluid communication between the interior of the production tubing and the interior of the screen via the flow passage 138. Circumferential seal 146 sealingly engages the annular sleeve 142 and inner diameter 144.
The plug 132 prevents gravel, pumped down the tubing from the earth's surface, from filling the interior of the sand screen during the gravel pack operation. The plug 132 is later ejected, as shown in FIG. 6B, to permit flow of fluids from the interior of the screen, through the flow passage 138, and into the production tubing for transport to the earth's surface. A circumferential seal 148 sealingly engages the plug 132 and sleeve 142 and permits a pressure differential to be created across the plug to shear shear pins 150 which extend radially through the sleeve 142 and into the plug.
Radially extending ports 152 formed through the lower housing 128 are initially open, as shown in FIG. 6A, permitting fluid communication between the flow passage 138 and the wellbore external to the apparatus 124. During the gravel pack operation, gravel may be pumped through the ports 152 and into the annular area between the screen and the casing.
Shear pins 154, extending radially through the upper housing 126 and the sleeve 136, releasably secure the sleeve against axial movement relative to the upper housing. When shear pins 154 are sheared, sleeve 136 is permitted to move downwardly until shoulder 156 on the sleeve 136 contacts shoulder 158 formed on the lower housing 128.
When sleeve 136 has been downwardly shifted, as shown in FIG. 6B, circumferential seals 160 straddle the ports 152 on the lower housing 128 and prevent fluid communication between the flow passage 138 and the wellbore external to the apparatus 124. Circumferential seal 162 sealingly engages the upper housing 126 and an upper end 164 of the lower housing 128, also preventing fluid communication between the flow passage 138 and the wellbore external to the apparatus 124.
Sleeve 136 is downwardly shifted within the lower housing 128 by a first predetermined pressure differential created across the expandable ball seat 130. The expandable ball seat 130 is of conventional construction and is in a radially compressed configuration, as viewed in FIG. 6A, when installed into the sleeve 136. Upwardly facing seal surface 166 on the ball seat 130, when in the radially compressed configuration, is smaller in diameter and is thus capable of sealingly engaging a ball 168 dropped or pumped down through the production tubing. It is to be understood that the ball 168 would preferably not be dropped through the production tubing during the gravel pack operation as it would interfere with the pumping of gravel through the apparatus 124. The ball 168 is preferably dropped through the production tubing when the gravel pack operation has been completed and it is desired to shift the sleeve 136 to close ports 152.
When the ball 168 sealingly engages the seal surface 166, a pressure differential may be created across the ball seat 130 by applying pressure to the interior of the production tubing at the earth's surface. Such a pressure differential downwardly biases the ball seat 130 against a ring 170, forcing radially sloping surface 172 formed on the ball seat 130 against radially sloping surface 174 on the ring. The contact between the sloping surfaces 172 and 174 further biases the ball seat 130 radially outward. The ring 170 is releasably secured against axial movement within the sleeve 136 with shear pins 176 extending radially through the sleeve and the ring.
When a first predetermined pressure differential has been created across the ball seat 130, shear pins 154 shear, permitting the sleeve 136 to downwardly shift, as described above. Lower housing 128 is initially coaxially attached to the upper housing 126, as shown in FIG. 6A, with lugs 134 which are installed radially through openings 178 formed on the upper housing. Radially reduced outer diameter 180 on the sleeve 136 biases the lugs 134 radially outward so that they are radially larger than reduced inner diameter 182 on the lower housing 128. When, however, the sleeve 136 has been downwardly shifted, as shown in FIG. 6B, the lugs 134 are no longer radially outwardly biased by diameter 180 on the sleeve, and the lugs are permitted to displace radially inward. Inner diameter 182 on the lower housing 128 may then pass over the lugs 134, permitting the lower housing to separate from the upper housing 126.
Application of a second predetermined differential pressure across the ball seat 130, greater than the first pressure differential, will then cause the shear pins 176 to shear and permit the ball seat and ring 170 to downwardly shift and move axially into the inner diameter 144 of the lower housing 128, as shown in FIG. 6B. The ball seat 130 is thus permitted to expand radially outward into the inner diameter 144. Such expansion of the ball seat 130 causes the seal surface 166 to have a diameter larger than that of the ball 168, which permits the ball to pass through the ball seat and the flow passage 138 to the plug 132. Thus, when the plug 132 is later expelled from the annular sleeve 142, as shown in FIG. 6B and described above, the ball 168 will also be expelled.
In a preferred mode of operation, the apparatus 124 is installed between the production tubing and the sand control screen as described above. During the gravel pack operation, gravel is pumped down through the tubing and into flow passage 138. The gravel exits through the ports 152 and flows into the wellbore. When the gravel pack operation is completed, the ball 168 is dropped or pumped down through the tubing to the ball seat 130. Pressure is applied to the tubing at the surface until a first predetermined pressure differential is created across the ball seat 130, shearing the shear pins 154 and forcing the sleeve 136 to shift downward. At this point, ports 152 are closed, preventing fluid communication between the wellbore and the flow passage 138, and lugs 134 are no longer biased radially outward. A second predetermined pressure differential is then created across the ball seat 130, causing the shear pins 176 to shear and forcing the ring 170 and ball seat 130 to shift downward into diameter 144 of the lower housing 128 and permitting the ball seat to expand radially outward. The ball 168 passes through the expanded ball seat 130. A third predetermined pressure differential is then created across the plug 132 by applying pressure to the tubing at the earth's surface, thereby shearing shear pins 150, and expelling the plug 132 and the ball 168 from the sleeve 142. The tubing may then be removed from the wellbore when desired, without displacing or otherwise disturbing the screen or gravel pack.
The foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims. | A gravel pack apparatus and associated method of completing subterranean wells provides convenient and economical gravel packing operations, permitting a sand control screen to be run into the well attached to the apparatus which is, in turn, attached to production tubing, and further permitting the tubing to be detached from the screen. In a preferred embodiment, a gravel pack apparatus has interoperable valve and tubing release portions. The valve portion may be closed after the gravel packing operation is completed. Closure of the valve portion activates the release portion, permitting the apparatus to be separated. | Identify and summarize the most critical features from the given passage. | [
"BACKGROUND OF THE INVENTION The present invention relates generally to tools used to complete subterranean wells and, in a preferred embodiment thereof, more particularly provides apparatus for use in gravel pack operations and methods of using same.",
"Gravel pack operations are typically performed in subterranean wells to prevent fine particles of sand or other debris from being produced along with valuable fluids extracted from a geological formation.",
"If produced (i.e., brought to the earth's surface), the fine sand tends to erode production equipment, clog filters, and present disposal problems.",
"It is, therefore, economically and environmentally advantageous to ensure that the fine sand is not produced.",
"In the subterranean well, a tubular protective casing usually separates the formation containing the fine sand particles from the wellbore.",
"The casing is typically perforated opposite the formation to provide flowpaths for the valuable fluids from the formation to the wellbore.",
"If production tubing is simply lowered into the wellbore and the fluids are allowed to flow directly from the formation, into the wellbore, and through the production tubing to the earth's surface, the fine sand will be swept along with the fluids and will be carried to the surface by the fluids.",
"Conventional gravel pack operations prevent the fine sand from being swept into the production tubing by installing a sand screen on the end of the production tubing.",
"The wellbore in an annular area between the screen and the casing is then filled with a relatively large grain sand (i.e., "gravel").",
"The gravel prevents the fine sand from packing off around the production tubing and screen, and the screen prevents the large grain sand from entering the production tubing.",
"A problem, which is present in every conventional gravel pack operation, is how to place the gravel in the annular area between the screen and the casing opposite the formation.",
"If the screen is merely attached to the bottom of the production tubing when it is installed in the wellbore, the gravel cannot be pumped down the production tubing because the screen will prevent it from exiting the tubing.",
"The gravel cannot be dropped into the wellbore annular area from the earth's surface because a packer is usually installed between the production tubing and the casing above the formation, and this method would be very inaccurate in packerless completions as well.",
"One solution has been to run the production tubing into the wellbore without the screen being attached to the tubing.",
"A landing nipple is installed at or near the bottom of the tubing before running the tubing into the well.",
"When the landing nipple has been properly positioned above the formation, a screen is lowered into the tubing from the earth's surface on a slickline or wireline.",
"The screen is landed in the nipple in the tubing so that it extends outwardly and downwardly from the tubing and is positioned opposite the formation.",
"Gravel is then pumped down the tubing from the earth's surface, through a small space between the nipple and the screen, and outwardly into the annular area between the screen and the casing opposite the formation.",
"This method is known as "through tubing gravel packing", since the gravel is pumped through the tubing.",
"This method has several disadvantages, however.",
"One disadvantage is that the screen must be installed into the tubing as a separate operation.",
"This requires coordination with a slickline or wireline service, time spent rigging up and rigging down special equipment such as lubricators needed for these operations, and the inability to conveniently perform such operations in wells which are horizontal or nearly horizontal.",
"In some instances, the screen is run in with the tubing, already landed in the nipple in the tubing.",
"In those instances, a slickline operation is still needed to retrieve the screen from the tubing.",
"Another disadvantage of the above method is that the screen must be able to pass through the tubing.",
"This means that the size of the screen (at least its outer diameter) can be no larger than the tubing's inner drift diameter.",
"In order to have a sufficiently large screen surface area, very long screens must sometimes be utilized with this method.",
"Additionally, since there is usually only a very small radial gap between the screen (or the slickline tool used to place the screen in the nipple) and the landing nipple, only a very small flow area is available for pumping the gravel out of the tubing and into the annular area of the well.",
"Yet another disadvantage of the above method is that the tubing may not be conveniently removed from the wellbore for replacing the packer, completing other formations in the well, maintenance, etc.",
"The method requires the screen to be removed along with the tubing, or the screen must be removed by wireline or slickline prior to removing the tubing.",
"In either case, the gravel pack will be destroyed as the gravel falls into the void created when the screen is removed.",
"From the foregoing, it can be seen that it would be quite desirable to provide apparatus for gravel pack operations which does not require the screen to be positioned as a separate operation and does not require the screen to pass through the tubing, but which provides a large flow area for pumping the gravel into the annular area of the well and provides for convenient detachment of the tubing from the screen for removal of the tubing from the wellbore.",
"It is accordingly an object of the present invention to provide such apparatus and associated methods of using same.",
"SUMMARY OF THE INVENTION In carrying out the principles of the present invention, in accordance with an embodiment thereof, gravel pack apparatus is provided which is a unique valve and release mechanism.",
"The valve permits pumping gravel therethrough with the screen attached to the bottom of the tubing, and the release mechanism permits convenient detachment of the tubing from the screen.",
"In broad terms, apparatus is provided which includes tubular first and second housings, a ball seat, a plurality of collets, a flow passage and a tubular sleeve.",
"The second housing is coaxially disposed relative to the first housing, with an end of the first housing being proximate an end of the second housing.",
"The flow passage extends through the first and second housings.",
"The collets extend axially between the first housing and the second housing and releasably secure the first housing against axial displacement relative to the second housing.",
"The tubular sleeve is coaxially disposed within the first and second housings and has an outer diameter radially inwardly adjacent the collets.",
"The sleeve outer diameter radially outwardly biases the collets, and the sleeve is disposed adjacent the ball seat, such that the sleeve is capable of axial movement relative to the collets when a pressure differential is created across the ball seat.",
"Additionally, apparatus is provided which includes tubular first and second housings, a ball seat, a lug, a flow passage, and a tubular sleeve.",
"The flow passage extends through the first and second housings.",
"The first housing has an end portion and a radially extending opening formed through the end portion.",
"The second housing has an end portion radially outwardly and coaxially disposed relative to the first housing end portion.",
"The lug extends radially through the opening and between the first housing end portion and the second housing end portion.",
"The lug releasably secures the first housing against axial displacement relative to the second housing.",
"The tubular sleeve is coaxially disposed within the first housing.",
"It has an outer diameter radially inwardly adjacent the lug which radially outwardly biases the lug.",
"The sleeve is disposed adjacent the ball seat, such that the sleeve is capable of axial movement relative to the lug when a pressure differential is created across the ball seat.",
"A method of completing a subterranean well having a wellbore intersecting a formation is also provided, which method includes the steps of providing a gravel pack device, providing production tubing, attaching the gravel pack device to the production tubing, and inserting the gravel pack device and production tubing into the wellbore.",
"The gravel pack device includes first and second tubular housings, a collet member releasably securing the first tubular housing in a coaxial and adjoining relationship with the second tubular housing, an expandable circumferential seal surface, an internal flow passage extending axially through the seal surface and the first housing, and a tubular sleeve having an outer side surface.",
"The tubular sleeve has a first position, in which the sleeve outer side surface radially biases the collet member to secure the first and second housings against axial displacement therebetween, and a second position, axially displaced relative to the collet member from the first position, in which the sleeve outer side surface unbiases the collet member to release the first and second housings for axial displacement therebetween.",
"The seal surface is capable of biasing the sleeve to axially displace from the first position to the second position when a pressure differential is created across the seal surface.",
"The method also includes the steps of creating the pressure differential across the seal surface and releasing the first and second housings for axial displacement therebetween.",
"Additionally, a method of gravel packing a formation intersected by a subterranean wellbore is also provided.",
"The method includes the steps of providing a device, production tubing, and a sand control screen, attaching the device between the tubing and the sand control screen, and inserting the tubing, device, and sand control screen into the wellbore.",
"The device includes first and second tubular housings, a ball seat, collets, a flow passage, a plug releasably secured in the flow passage, a flow port, and a tubular sleeve.",
"The second housing is coaxially disposed relative to the first housing with an end of the first housing being proximate an end of the second housing.",
"The ball seat is coaxially disposed within the first housing.",
"The flow port is capable of permitting fluid communication between the flow passage and the wellbore.",
"The collets extend axially between the first housing end and the second housing end and releasably secure the first housing against axial displacement relative to the second housing.",
"The sleeve is coaxially disposed within the first and second housings and has an outer diameter radially inwardly adjacent the collets.",
"The sleeve outer diameter radially outwardly biases the collets, and the sleeve is disposed adjacent the ball seat, such that the sleeve is capable of axial movement relative to the flow port and the collets when a first predetermined pressure differential is created across the ball seat.",
"The plug is capable of being expelled from the flow passage when a second predetermined pressure differential is created across the plug.",
"The method further includes the steps of positioning the sand control screen in a predetermined axial position in the wellbore relative to the formation and forcing a gravel pack slurry through the production tubing, into the flow passage, through the flow port, into the wellbore, and into an annular area radially intermediate the sand control screen and the formation.",
"The first predetermined pressure differential is created across the ball seat by sealingly engaging a ball with the ball seat and applying pressure to the production tubing.",
"The second predetermined pressure differential is created across the plug by applying pressure to the production tubing after the first predetermined pressure differential is created.",
"The use of the disclosed apparatus and methods of using same permits larger screens to be used in through-tubing gravel pack operations, provides larger flow areas through which to pump the gravel, eliminates separate screen installation and removal by wireline or slickline operations, and permits convenient removal of the tubing while the screen and gravel pack remain undisturbed in the well.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-1B are cross-sectional views of a first apparatus embodying principles of the present invention;",
"FIGS. 2A-2B are highly schematicized cross-sectional views of a method embodying principles of the present invention, using the first apparatus;",
"FIGS. 3A-3B are cross-sectional views of a second apparatus embodying principles of the present invention;",
"FIGS. 4A-4B are cross-sectional views of a third apparatus embodying principles of the present invention;",
"FIGS. 5A-5C are cross-sectional views of a fourth apparatus embodying principles of the present invention;",
"and FIGS. 6A-6B are cross-sectional views of a sixth apparatus embodying principles of the present invention.",
"DETAILED DESCRIPTION The following descriptions of preferred embodiments of the present invention describe use of the embodiments in gravel packing operations in subterranean wellbores.",
"It is to be understood, however, that apparatus and methods embodying principles of the present invention may be utilized in other operations, such as fracturing or acidizing operations.",
"Illustrated in FIGS. 1A and 1B is a gravel pack apparatus 10 which embodies principles of the present invention.",
"In the following detailed description of the apparatus 10 representatively illustrated in FIGS. 1A and 1B, and subsequent apparatus, methods, and figures described hereinbelow, directional terms such as "upper", "lower", "upward", "downward", etc.",
"will be used in relation to the apparatus 10 as it is depicted in the accompanying figures.",
"It is to be understood that the apparatus 10 and subsequent apparatus and methods described hereinbelow may be utilized in vertical, horizontal, inverted, or inclined orientations without deviating from the principles of the present invention.",
"The apparatus 10 includes a tubular upper housing 12, a tubular lower housing 14, an expandable ball seat 16, a plug 18, collets 20, and a tubular sleeve 22.",
"FIG. 1A shows the apparatus 10 in a configuration in which it is run into the wellbore prior to the gravel pack operation.",
"FIG. 1B shows the apparatus 10 in a configuration subsequent to the gravel pack operation.",
"Comparing FIG. 1B to FIG. 1A, note that the expandable ball seat 16 has expanded radially outward within the upper housing 12, the sleeve 22 has been shifted downward within the upper housing, the plug 18 has been ejected out of the sleeve, and the lower housing 14 has separated from the upper housing 12.",
"When initially run into the wellbore prior to the gravel pack operation, as shown in FIG. 1A, the apparatus 10 is installed between the production tubing and the sand control screen (not shown in FIGS. 1A and 1B).",
"The tubing is threadedly and sealingly attached to the upper housing 12 at upper connector 24.",
"An interior axial flow passage 26 is thus placed in fluid communication with the interior of the production tubing.",
"The screen is threadedly and sealingly attached to the lower housing 14 at lower end 28.",
"Plug 18 in sleeve 22 prevents fluid communication between the interior of the production tubing and the interior of the screen via the flow passage 26.",
"Plug 18 prevents gravel, pumped down the tubing from the earth's surface, from filling the interior of the sand screen during the gravel pack operation.",
"The plug 18 is later ejected, as shown in FIG. 1B, to permit flow of fluids from the interior of the screen, through the flow passage 26, and into the production tubing for transport to the earth's surface.",
"A circumferential seal 34 sealingly engages the plug 18 and sleeve 22 and permits a pressure differential to be created across the plug to shear shear pins 36 which extend radially through the sleeve 22 and into the plug.",
"Radially extending ports 30 on the sleeve 22 are initially aligned with radially extending ports 32 on the upper housing 12, permitting fluid communication between the flow passage 26 and the wellbore external to the apparatus 10.",
"During the gravel pack operation, gravel may be pumped through the ports 30 and 32 and into the annular area between the screen and the casing.",
"Radially extending and circumferentially spaced splines 33 formed on lower housing 14 permit fluid flow longitudinally between the wellbore external to the upper housing 12 and the wellbore below the lower housing as further described below.",
"The aligned relationship of the ports 30 and 32 is releasably secured by shear pins 38 threadedly installed radially through the upper housing 12 and into the sleeve 22.",
"When shear pins 38 are sheared, sleeve 22 is permitted to move downwardly until radially sloping shoulder 40 on the sleeve 22 contacts radially sloping shoulder 42 on the upper housing 12.",
"When sleeve 22 has been downwardly shifted, as shown in FIG. 1B, circumferential seals 44, which sealingly engage the sleeve and upper housing 12, straddle the ports 32 on the upper housing 12 and prevent fluid communication between the flow passage 26 and the wellbore external to the apparatus 10.",
"Circumferential seals 46, 48, and 50 sealingly engage the upper connector 24 and an upper end 52 of the upper housing 12, the sleeve 22 and the upper housing, and the sleeve and the lower housing 14, respectively, also preventing fluid communication between the flow passage 26 and the wellbore external to the apparatus 10.",
"Sleeve 22 is downwardly shifted within the upper housing 12 by the expandable ball seat 16.",
"The expandable ball seat 16 is of conventional construction and is in a radially compressed configuration, as viewed in FIG. 1A, when installed into the upper connector 24.",
"Upwardly facing seal surface 54 on the ball seat 16, when in the radially compressed configuration, is smaller in diameter than, and is thus capable of sealingly engaging, a ball 56 dropped or pumped down through the production tubing.",
"It is to be understood that the ball 56 would preferably not be dropped through the production tubing during the gravel pack operation as it would interfere with the pumping of gravel through the apparatus 10.",
"The ball 56 is preferably dropped through the production tubing when the gravel pack operation has been completed and it is desired to shift the sleeve 22 to close ports 32.",
"When the ball 56 sealingly engages the seal surface 54, a pressure differential may be created across the ball seat 16 by applying pressure to the interior of the production tubing at the earth's surface.",
"Such a pressure differential downwardly biases the ball seat 16 against the sleeve 22, forcing radially sloping surface 57 on the ball seat 16 against radially sloping surface 58 on the sleeve.",
"The contact between the sloping surfaces 57 and 58 further biases the ball seat 16 radially outward.",
"When sufficient pressure differential has been created across the ball seat 16, shear pins 38 shear, permitting the sleeve 22 to downwardly shift, as described above, and permitting the ball seat 16 to expand radially outward into radially enlarged inner diameter 60 within the upper housing 12.",
"Such expansion of the ball seat 16 causes the seal surface 54 to have an inner diameter larger than that of the ball 56, which permits the ball to pass through the ball seat and the flow passage 26 to the plug 18.",
"Thus, when the plug 18 is later expelled from the sleeve 22, as shown in FIG. 1B and described above, the ball 56 will also be expelled.",
"Lower housing 14 is initially coaxially attached to the upper housing 12, as shown in FIG. 1A, with collets 20 which are threadedly installed onto the upper housing.",
"Radially enlarged outer diameter 62 on the sleeve 22 biases the collets 20 radially outward so that radially extending projections 64 on the collets are radially larger than reduced inner diameter 66 on the lower housing 14.",
"When, however, the sleeve 22 has been downwardly shifted, as shown in FIG. 1B, the collets 20 are no longer radially outwardly biased by diameter 62 on the sleeve, and the collets are permitted to flex radially inward.",
"Inner diameter 66 on the lower housing 14 may then pass over the projections 64, permitting the lower housing to separate from the upper housing 12.",
"In a preferred mode of operation, the apparatus 10 is installed between the production tubing and the sand control screen as described above.",
"During the gravel pack operation, gravel is pumped down through the tubing and into flow passage 26.",
"The gravel exits through the aligned ports 30 and 32 and flows into the wellbore.",
"When the gravel pack operation is completed, the ball 56 is dropped or pumped down through the tubing to the ball seat 16.",
"Pressure is applied to the tubing at the surface until a first predetermined pressure differential is created across the ball seat 16, shearing the shear pins 38 and forcing the sleeve 22 to shift downward.",
"At this point, ports 32 are closed, preventing fluid communication between the wellbore and the flow passage 26, and collets 20 are no longer biased radially outward.",
"The ball 56 passes through the ball seat 16.",
"A second predetermined pressure differential is then created across the plug 18 by applying pressure to the tubing at the earth's surface, thereby shearing shear pins 36, and expelling the plug 18 and the ball 56 from the sleeve 22.",
"The tubing may be removed from the wellbore when desired, without displacing or otherwise disturbing the screen or gravel pack.",
"Turning now to FIGS. 2A and 2B, a method 70 of using the apparatus 10 is representatively illustrated.",
"It is to be understood that, with suitable modifications, other apparatus may be utilized in method 70, including other apparatus described hereinbelow, without departing from the principles of the present invention.",
"FIG. 2A shows the apparatus 10 operatively installed between production tubing 72, which extends to the earth's surface and is attached to the upper housing 12, and sand control screen 74.",
"The screen 74, apparatus 10, and tubing 72 are lowered into wellbore 76, which intersects formation 78 and is lined with protective casing 80.",
"A conventional tubing hanger 82 has previously been set in the casing 80 a predetermined distance above the formation 78.",
"As the screen 74, apparatus 10, and tubing 72 are lowered into the wellbore, splines 33 on the lower housing 14 engage the tubing hanger 82, thereby positioning the screen 74 in the wellbore 76 opposite the formation 78.",
"Alternatively, splines 33 could engage, for example, a nipple (not shown) disposed in a string of production tubing (not shown), or the nipple could be suspended from a packer (not shown) set in the casing 80.",
"A gravel pack slurry 84 is then pumped down the tubing 72 from the earth's surface.",
"The slurry 84 enters the flow passage 26 of the apparatus 10 and then exits the apparatus through open ports 32.",
"The slurry 84 then flows downwardly in the wellbore 76 and passes between the splines 33 and the tubing hanger 82.",
"From the tubing hanger 82, the slurry 84 enters an annular area 86 below the tubing hanger and radially intermediate the screen 74 and the casing 80.",
"Slurry 84 is pumped into the annular area 86 until it forms a gravel pack 88 as shown in FIG. 2B.",
"The ball 56 is then dropped or pumped down the tubing 72, the ball sealingly contacting the ball seat 16.",
"Pressure is applied to the tubing 72 to shift the sleeve 22 downward and close ports 32 as described above.",
"The collets 20 are also no longer biased radially outward after the sleeve 22 is downwardly shifted, but the upper housing 12 is not yet separated from the lower housing 14.",
"Pressure is again applied to the tubing 72 to expel the plug 18 and ball 56 from the sleeve 22 as described above.",
"The plug 18 and ball 56 then drop into the screen 74 as shown in FIG. 2B.",
"At this point the tubing 72 is in fluid communication with the screen 74 and fluids 90 may flow from the formation 78, through the gravel pack 88 in the annular area 86, through the screen 74, through the flow passage 26 of the apparatus 10, and upwardly through the tubing 72 to the earth's surface.",
"If desired, the tubing 72 may be conveniently removed from the wellbore 76 by raising the tubing to separate the upper housing 12 from the lower housing 14.",
"The lower housing 14 remains in the wellbore 76, supporting the screen 74 opposite the formation 78 in the gravel pack 88 as shown in FIG. 2B.",
"The screen 74 and gravel pack 88 are not disturbed when the tubing 72 is removed from the wellbore 76.",
"Note that, in the above-described method 70, screen 74 is not required to pass through the tubing 72 and, therefore, has an outer diameter which is limited only by the casing 80 or tubing hanger 82.",
"Note also, that a relatively large flow area is available for slurry 84 to flow between the lower housing 14 and the tubing hanger 82 via the splines 33.",
"Additionally, no separate wireline or slickline operation is needed in method 70 to position or remove the screen 74.",
"Turning now to FIGS. 3A and 3B, an apparatus 10a is shown which is a modified form of the apparatus 10 shown in FIGS. 1A-2B.",
"Elements of apparatus 10a which are similar to those elements previously described are indicated in FIGS. 3A and 3B with the same reference numerals, but with an added suffix "a".",
"Apparatus 10a functions similar to apparatus 10, the major difference being that ports 32a are initially closed, as shown in FIG. 3A.",
"Ports 32a are axially displaced from ports 94 on sleeve 96.",
"Circumferential seal 98 sealingly engages the sleeve 96 and upper housing 12a and is disposed axially intermediate ports 94 and 32a, thereby preventing fluid communication between the ports.",
"When the sleeve 96 is downwardly shifted, as shown in FIG. 3B, ports 94 and 32a are aligned and fluid communication is established between the flow passage 26a and the wellbore external to the apparatus 10a.",
"It will be readily appreciated by one skilled in the art that if the flow passage 26a is in fluid communication with the wellbore and the interior of lower end 28a is in fluid communication with the wellbore, a pressure differential cannot be created across the plug 18a to expel the plug and ball 56a from the sleeve 96.",
"Thus, if the plug 18a is desired to be expelled from the sleeve 96 of apparatus 10a by pressure differential created across the plug, a means, such as gravel pack 88 (see FIG. 2B), to restrict fluid communication between the flow passage 26a and the interior of the lower end 28a via the wellbore must be utilized.",
"Thus, apparatus 10a is useful in circumstances in which it is desired to run the apparatus into the wellbore with ports 32a initially closed.",
"The ports 32a may then be opened by dropping or pumping ball 56a down the tubing and applying a predetermined pressure to shear shear pins 38a and downwardly shift the sleeve 96.",
"When sleeve 96 has been shifted downward, ports 32a and 94 are aligned and permit flow therethrough, and collets 20a are no longer radially outwardly biased by enlarged outer diameter 62a.",
"The upper housing 12a may then be separated from lower housing 14a, and, if a means to seal flow passage 26a against fluid communication with lower end 28a has been utilized, the ball 56a and plug 18a may be expelled from the sleeve 96 by applying a second pressure differential to shear shear pins 36a.",
"Illustrated in FIGS. 4A and 4B is an apparatus 10b which is another modified form of the apparatus 10 shown in FIGS. 1A-2B.",
"Elements of apparatus 10b which are similar to those elements previously described are indicated in FIGS. 4A and 4B with the same reference numerals, but with an added suffix "b".",
"Apparatus 10b functions similar to apparatus 10, the major difference being that there are no ports 30 and 32 and no plug 18.",
"The flow passage 26b extends axially through the apparatus 10b, permitting flow therethrough at all times, except for when ball 56b is dropped or pumped down to ball seat 16b and engages seal surface 54b.",
"Circumferential seal 102 sealingly engages sleeve 100 and upper housing 12b and is disposed axially intermediate shear pins 38b and upper connector 24b.",
"The sleeve 100 is shifted downward by pumping or dropping ball 56b into the apparatus lob so that the ball 56b sealingly engages the ball seat 16b.",
"A predetermined pressure is created across the ball seat 16b, shearing shear pins 38b.",
"The ball seat 16b then expands radially outward and ball 56b is permitted to pass through flow passage 26b.",
"When sleeve 100 is downwardly shifted, as shown in FIG. 4B, collets 20b are no longer radially outwardly biased by enlarged outer diameter 62b.",
"The upper housing 12b may then be separated from lower housing 14b.",
"Thus, apparatus 10b is useful in circumstances in which it is desired to run the apparatus into the wellbore with no fluid communication between the flow passage 26b and the wellbore external to the apparatus 10b, or when such fluid communication is otherwise provided, and then to separate the upper housing 12b from the lower housing 14b.",
"FIGS. 5A-5C show an apparatus 10c which is yet another modified form of the apparatus 10 shown in FIGS. 1A-2B.",
"Elements of apparatus 10c which are similar to those elements previously described are indicated in FIGS. 5A-5C with the same reference numerals, but with an added suffix "c".",
"Apparatus 10c functions similar to apparatus 10, the major difference being the inclusion of annular ring 106 in annular space 108 axially intermediate sloping surfaces 40c and 42c, and radially intermediate the sleeve 22c and upper housing 12c.",
"Annular ring 106 has upper and lower radially sloping surfaces 110 and 112, respectively, and is releasably secured by shear pins 114 against axial movement relative to the upper housing 12c.",
"As will be readily appreciated by consideration of the following description, annular ring 106 permits the steps of closing the ports 32c and separating the housings 12c and 14c to be performed separately.",
"When the sleeve 22c is downwardly shifted, as shown in FIG. 5B, ports 32c are closed, preventing fluid communication between the flow passage 26c and the wellbore external to the apparatus 10c.",
"In this configuration of the apparatus 10c, sloping shoulder 40c on sleeve 22c is in contact with sloping shoulder 110 of annular ring 106.",
"The ball seat 16c is expanded radially outward, permitting the ball 56c to pass through the flow passage 26c.",
"Plug 18c and ball 56c may be expelled from the sleeve 22c by creating a sufficient differential pressure across the plug to shear shear pins 36c.",
"However, unlike apparatus 10 as shown in FIG. 1B, the upper housing 12c may not be separated from the lower housing 14c with the apparatus 10c in the configuration shown in FIG. 5B, because the collets 20c remain radially outwardly biased by outer diameter 62c on the sleeve 22c.",
"In order to separate upper housing 12c from lower housing 14c, a second ball 116 is dropped or pumped down into the apparatus 10c.",
"The ball 116 has a larger diameter than the first ball 56c, but is still able to pass through the expanded ball seat 16c as shown in FIG. 5C.",
"The ball 116 has a diameter which is, however, too large to pass through the sleeve 22c.",
"Instead, the ball 116 sealingly engages a circumferential seal surface 118 on the sleeve 22c, disposed adjacent the sloping surface 58c.",
"A pressure differential may now be created across the ball 116 to downwardly bias the sleeve 22c and shear shear pins 114.",
"The sleeve 22c and annular ring 106 may then shift downwardly until sloping shoulder 112 contacts sloping shoulder 42c.",
"When the sleeve 22c is thus further shifted downwardly, outer diameter 62c no longer radially outwardly biases the collets 20c and the upper housing 12c may be separated from the lower housing 14c.",
"Additionally, ports 32c are again opened, permitting fluid communication between the wellbore and the apparatus 10c interior above the ball 116.",
"In a preferred mode of operation, the apparatus 10c is installed between the production tubing and the sand control screen as described above.",
"During the gravel pack operation, gravel is pumped down through the tubing and into flow passage 26c.",
"The gravel exits through the aligned ports 30c and 32c and flows into the wellbore.",
"When the gravel pack operation is completed, the ball 56c is dropped or pumped down through the tubing to the ball seat 16c.",
"Pressure is applied to the tubing at the surface until a first predetermined pressure differential is created across the ball seat 16c, shearing the shear pins 38c and forcing the sleeve 22c to shift downward.",
"At this point, ports 32c are closed, preventing fluid communication between the wellbore and the flow passage 26c.",
"The ball 56c passes through the ball seat 16c.",
"A second predetermined pressure differential is then created across the plug 18c by applying pressure to the tubing at the earth's surface, thereby shearing shear pins 36c, and expelling the plug 18c and the ball 56c from the sleeve 22c.",
"The well may then go into production, with fluids flowing from the formation, through the gravel pack, through the screen, and upwardly through the flow passage 26c and the tubing to the earth's surface.",
"If it is later desired to remove the tubing from the wellbore without displacing or otherwise disturbing the screen and gravel pack, a second ball 116 is dropped or pumped down the tubing and a third predetermined pressure differential is created across the ball to shear shear pins 114.",
"The sleeve 22c then shifts further downwardly, permitting the collets 20c to flex radially inward.",
"The tubing may then be removed from the wellbore, any fluid remaining in the tubing being able to flow out of the re-opened ports 32c into the wellbore during the tubing's removal.",
"Thus, apparatus 10c is useful in circumstances in which it is desired to run the apparatus into the wellbore with ports 32c initially open, perform the gravel pack operation, close the ports, and expel the plug 18c and ball 56c before putting the well into production, but it is not desired to concurrently release the upper housing 12c for separation from the lower housing 14c.",
"This permits the tubing, apparatus 10c, and screen to later be removed from the wellbore together (the upper and lower housings 12c and 14c, respectively, remaining attached), or, if it is desired to remove the tubing, but not the screen, from the wellbore, the second ball 116 may be dropped or pumped down through the tubing to separate the upper and lower housings 12c and 14c, respectively.",
"FIGS. 6A and 6B show another apparatus 124 embodying principles of the present invention.",
"The apparatus 124 includes an upper housing 126, a lower housing 128, an expandable ball seat 130, a plug 132, collets or lugs 134, and a sleeve 136.",
"FIG. 6A shows the apparatus 124 in a configuration in which it is run into the wellbore prior to the gravel pack operation.",
"FIG. 6B shows the apparatus 124 in a configuration subsequent to the gravel pack operation.",
"Comparing FIG. 6B to FIG. 6A, note that the expandable ball seat 130 has expanded radially outward within the lower housing 128, the sleeve 136 has been shifted downward within the lower housing, the plug 132 has been ejected, and the lower housing 128 has separated from the upper housing 126.",
"When initially run into the wellbore prior to the gravel pack operation, as shown in FIG. 6A, the apparatus 124 is installed between the production tubing and the sand control screen.",
"The tubing is threadedly and sealingly attached to the upper housing 126 threaded connection 137.",
"An interior axial flow passage 138 is thus placed in fluid communication with the interior of the production tubing.",
"The screen is threadedly and sealingly attached to the lower housing 128 at threaded connection 140.",
"Plug 132 is retained in an annular sleeve 142 disposed in an inner diameter 144 of lower housing 128 and prevents fluid communication between the interior of the production tubing and the interior of the screen via the flow passage 138.",
"Circumferential seal 146 sealingly engages the annular sleeve 142 and inner diameter 144.",
"The plug 132 prevents gravel, pumped down the tubing from the earth's surface, from filling the interior of the sand screen during the gravel pack operation.",
"The plug 132 is later ejected, as shown in FIG. 6B, to permit flow of fluids from the interior of the screen, through the flow passage 138, and into the production tubing for transport to the earth's surface.",
"A circumferential seal 148 sealingly engages the plug 132 and sleeve 142 and permits a pressure differential to be created across the plug to shear shear pins 150 which extend radially through the sleeve 142 and into the plug.",
"Radially extending ports 152 formed through the lower housing 128 are initially open, as shown in FIG. 6A, permitting fluid communication between the flow passage 138 and the wellbore external to the apparatus 124.",
"During the gravel pack operation, gravel may be pumped through the ports 152 and into the annular area between the screen and the casing.",
"Shear pins 154, extending radially through the upper housing 126 and the sleeve 136, releasably secure the sleeve against axial movement relative to the upper housing.",
"When shear pins 154 are sheared, sleeve 136 is permitted to move downwardly until shoulder 156 on the sleeve 136 contacts shoulder 158 formed on the lower housing 128.",
"When sleeve 136 has been downwardly shifted, as shown in FIG. 6B, circumferential seals 160 straddle the ports 152 on the lower housing 128 and prevent fluid communication between the flow passage 138 and the wellbore external to the apparatus 124.",
"Circumferential seal 162 sealingly engages the upper housing 126 and an upper end 164 of the lower housing 128, also preventing fluid communication between the flow passage 138 and the wellbore external to the apparatus 124.",
"Sleeve 136 is downwardly shifted within the lower housing 128 by a first predetermined pressure differential created across the expandable ball seat 130.",
"The expandable ball seat 130 is of conventional construction and is in a radially compressed configuration, as viewed in FIG. 6A, when installed into the sleeve 136.",
"Upwardly facing seal surface 166 on the ball seat 130, when in the radially compressed configuration, is smaller in diameter and is thus capable of sealingly engaging a ball 168 dropped or pumped down through the production tubing.",
"It is to be understood that the ball 168 would preferably not be dropped through the production tubing during the gravel pack operation as it would interfere with the pumping of gravel through the apparatus 124.",
"The ball 168 is preferably dropped through the production tubing when the gravel pack operation has been completed and it is desired to shift the sleeve 136 to close ports 152.",
"When the ball 168 sealingly engages the seal surface 166, a pressure differential may be created across the ball seat 130 by applying pressure to the interior of the production tubing at the earth's surface.",
"Such a pressure differential downwardly biases the ball seat 130 against a ring 170, forcing radially sloping surface 172 formed on the ball seat 130 against radially sloping surface 174 on the ring.",
"The contact between the sloping surfaces 172 and 174 further biases the ball seat 130 radially outward.",
"The ring 170 is releasably secured against axial movement within the sleeve 136 with shear pins 176 extending radially through the sleeve and the ring.",
"When a first predetermined pressure differential has been created across the ball seat 130, shear pins 154 shear, permitting the sleeve 136 to downwardly shift, as described above.",
"Lower housing 128 is initially coaxially attached to the upper housing 126, as shown in FIG. 6A, with lugs 134 which are installed radially through openings 178 formed on the upper housing.",
"Radially reduced outer diameter 180 on the sleeve 136 biases the lugs 134 radially outward so that they are radially larger than reduced inner diameter 182 on the lower housing 128.",
"When, however, the sleeve 136 has been downwardly shifted, as shown in FIG. 6B, the lugs 134 are no longer radially outwardly biased by diameter 180 on the sleeve, and the lugs are permitted to displace radially inward.",
"Inner diameter 182 on the lower housing 128 may then pass over the lugs 134, permitting the lower housing to separate from the upper housing 126.",
"Application of a second predetermined differential pressure across the ball seat 130, greater than the first pressure differential, will then cause the shear pins 176 to shear and permit the ball seat and ring 170 to downwardly shift and move axially into the inner diameter 144 of the lower housing 128, as shown in FIG. 6B.",
"The ball seat 130 is thus permitted to expand radially outward into the inner diameter 144.",
"Such expansion of the ball seat 130 causes the seal surface 166 to have a diameter larger than that of the ball 168, which permits the ball to pass through the ball seat and the flow passage 138 to the plug 132.",
"Thus, when the plug 132 is later expelled from the annular sleeve 142, as shown in FIG. 6B and described above, the ball 168 will also be expelled.",
"In a preferred mode of operation, the apparatus 124 is installed between the production tubing and the sand control screen as described above.",
"During the gravel pack operation, gravel is pumped down through the tubing and into flow passage 138.",
"The gravel exits through the ports 152 and flows into the wellbore.",
"When the gravel pack operation is completed, the ball 168 is dropped or pumped down through the tubing to the ball seat 130.",
"Pressure is applied to the tubing at the surface until a first predetermined pressure differential is created across the ball seat 130, shearing the shear pins 154 and forcing the sleeve 136 to shift downward.",
"At this point, ports 152 are closed, preventing fluid communication between the wellbore and the flow passage 138, and lugs 134 are no longer biased radially outward.",
"A second predetermined pressure differential is then created across the ball seat 130, causing the shear pins 176 to shear and forcing the ring 170 and ball seat 130 to shift downward into diameter 144 of the lower housing 128 and permitting the ball seat to expand radially outward.",
"The ball 168 passes through the expanded ball seat 130.",
"A third predetermined pressure differential is then created across the plug 132 by applying pressure to the tubing at the earth's surface, thereby shearing shear pins 150, and expelling the plug 132 and the ball 168 from the sleeve 142.",
"The tubing may then be removed from the wellbore when desired, without displacing or otherwise disturbing the screen or gravel pack.",
"The foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims."
] |
TECHNICAL FIELD
The present invention relates to fuel cells and, more particularly, to micro-porous layers incorporating non-uniformity of micro-porous media within diffusion media of fuel cells.
BACKGROUND OF THE INVENTION
Electrochemical fuel cells convert fuel and oxidant to electricity and reaction product. Solid polymer electrochemical fuel cells generally employ a membrane electrode assembly (“MEA”) comprising a solid polymer electrolyte or ion exchange membrane disposed between two planar electrode diffusion layers or substrates (diffusion media) formed of porous, electrically conductive sheet material, such as carbon fiber paper or carbon cloth. Suitable carbon fiber paper sheet material is available, for example, from Toray Industries, Inc. with grade designations such as TGP090, TGP060 and TGP030 having thicknesses of 0.27 mm, 0.19 mm and 0.10 mm, respectively, and a porosity of approximately 70%. Carbon fiber paper sheet material is also available in other thicknesses and porosities. Typically, the structure of the electrode substrate is substantially uniform, on a macroscopic scale, as it is traversed in plane (parallel to the planar major surfaces of the electrode substrate, i.e. the XY plane of FIG. 1 ) at any depth.
The MEA contains a layer of electrocatalyst, typically in the form of finely comminuted platinum, at each membrane/electrode substrate interface to induce the desired electrochemical reaction. The electrodes are electrically coupled to provide a path for conducting electrons between the electrodes through an external load.
At the anode, the fuel stream moves through the porous anode substrate (anode diffusion media) and is oxidized at the anode electrocatalyst layer. At the cathode, the oxidant stream moves through the porous cathode substrate (cathode diffusion media) and is reduced at the cathode electrocatalyst layer to form a reaction product. In electrochemical fuel cells employing hydrogen as the fuel and oxygen-containing air (or substantially pure oxygen) as the oxidant, the catalyzed reaction at the anode produces hydrogen cations (protons) from the fuel supply. The ion exchange membrane facilitates the migration of protons from the anode to the cathode. In addition to conducting protons, the membrane isolates the hydrogen-containing fuel stream from the oxygen-containing oxidant stream. At the cathode electrocatalyst layer, oxygen reacts with the protons that have crossed the membrane to form water as the reaction product.
In electrochemical fuel cells, the MEA is typically interposed between two fluid flowfield plates (anode and cathode plates). The plates act as current collectors, provide support to the MEA, provide means for access of the fuel and oxidant to the anode and cathode surfaces, respectively, and provide for the removal of water formed during operation of the cells. As the oxidant stream travels through the fluid flow channels typically formed in the fluid flowfield plates of the cell, the stream transports water passing through the cathode diffusion media that is produced as the product of the electrochemical reaction. The water is transported either as water vapor or as entrained water droplets. As a result, the portion of the flowfield into which the oxidant stream is introduced and through which the oxidant stream initially flows is drier than the portion of the flowfield through which the oxidant stream flows just prior to being exhausted from the fuel cell. In the latter portion of the oxidant flowfield, the oxidant stream can become saturated with water, in which case two phase flow occurs, that is, the oxidant stream contains water vapor and also has liquid water entrained in the stream.
Wet and dry regions of the flowfield can detrimentally affect fuel cell performance and accelerate the degradation of performance over time. Fuel cell performance is defined as the voltage output from the cell for a given current density; the higher the voltage for a given current density, the better. Control of water transport perpendicular to the plane of the electrodes (the Z direction of FIG. 1 ) away from the cathode to the oxidant flowfield; that is, movement of water in the direction from the cathode electrocatalyst layer to the oxidant flow channels (the “free stream”), is important to optimizing fuel cell performance. The “free stream” is the fluid stream within the reactant distribution channels.
In addition to the control of water transport, control of oxidant transport in the direction from the oxidant flow channels or free stream to the cathode electrocatalyst layer, is important to optimizing fuel cell performance. The concentration of oxygen at the electrocatalyst layer directly affects, fuel cell performance because oxygen concentration affects the rate of the electrochemical reaction.
The diffusion media serve several functions. One of these functions is the diffusion of reactant gases therethrough for reacting, within the respective catalyst layer. Another is to diffuse reaction products, namely water, away from the catalyst layer. Additionally, the diffusion media must conduct electrons and heat between the catalyst layers and flowfield plates.
The water generated by the electrochemical reaction on the catalytic layer on the cathode side mostly leaves the electrode as a vapor and condenses in the cathode diffusion media. If the condensed water remains around the catalytic layer, the oxygen gas is prevented from reaching the reaction area and cell performance is lowered. Avoiding a continuous water film in reactant gas pathways is critical to maintaining fuel cell performance.
To solve these problems, various countermeasures have been proposed and tried in the prior art, which include the use of a surface layer or layers on the diffusion media. A micro-porous layer (MPL), well known in the art, consisting of carbon or graphite particles mixed with a polymeric binder is the most common surface layer applied to the surfaces of diffusion media. An MPL has, typically, a pore size between 100 nanometers and 500 nanometers whereas diffusion media, typically, have pore sizes between 10 micrometers and 30 micrometers. Thus, the pore size of an MPL is smaller than the pore sizes of the diffusion media on which it is applied. This is one reason, among others, that an MPL provides an effective way to remove product water from the electrode. It also may reduce electrical contact resistance with the adjacent catalyst layer. An MPL may be applied to a surface of a diffusion media by, for example, screen printing, knife coating, and spraying, and is usually tailored, for example, empirically, to provide a surface coating of desired thickness with the given application technique. A commercial example of an MPL is known as Electrode Los Alamos Type produced by DeNora North America, Etek Division. Micro-porous layers are also described in various literature, for example, “Handbook of Fuel Cells—Fundamentals, Technology, and Applications”, edited by Wolf Vielstich, Hubert Gasteiger, Arnold Lamm, Volume 3, “Fuel Cell Technology and Applications”, Chapter 46, copyright 2003 John Wiley and Sons, Ltd.
It is pointed out that if the diffusion media are given a hydrophilic treatment, the cell performance will drop because the hydrophilic treatment would inhibit transfer of excess water to the flowfield for ultimate removal from the fuel cell.
FIG. 1 depicts a typical prior art subsection 100 of a fuel cell employing a first MPL 102 adjacent to an anode catalyst 104 on the surface 106 of an anode diffusion media 108 and a second MPL 110 adjacent to a cathode catalyst 112 on the surface 114 of a cathode diffusion media 116 , wherein 118 is the solid polymer electrolyte or ion exchange membrane. The MEA 120 , typically, consists of, collectively, elements 104 , 118 , and 112 .
Other methods have also been proposed to remove water from the catalyst layers, especially on the cathode side, such as placing holes in the diffusion media and embossing a pattern onto the diffusion media. Placing holes in an MPL having a uniform thickness perpendicular to the plane of the electrodes (the Z direction of FIG. 1 ) and a pattern of hydrophobic treatment on hydrophilic diffusion media have also been proposed. U.S. Pat. Nos. 5,840,438, 6,117,579, 6,521,369, and 6,579,639 exemplify these methods.
However, placing holes in an MPL or the diffusion media or embossing the diffusion media compromise the mechanical, electrical and thermal integrity of the diffusion media. Hydrophilic treatments of the diffusion, media would inhibit transfer of excess water to the flowfield for ultimate removal from the cell. In addition, by situating a MPL having a sharp interface with the substrate perpendicular to the plane of the electrodes (the Z direction of FIG. 1 ), water within the diffusion media can form a film at the MPL-substrate interface, for example surfaces 106 and 114 of FIG. 1 . Such a film, particularly if continuous, would significantly reduce transfer of reactant gases and reduce the limiting current.
Accordingly, what is needed in the art is a method providing better management of reactant gases and water within fuel cells.
SUMMARY OF THE INVENTION
The present invention is a continuous MPL, consisting of a micro-porous media, applied to one surface on the electrode side of at least one or more diffusion media of a fuel cell, wherein a geometric pattern, for example, dots or stripes, of micro-porous media is also introduced into each diffusion media to which the MPL has been applied. Accordingly, provided by the geometric pattern is a multiplicity of regions of micro-porous media interposed between a multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied wherein non-uniformity of micro-porous media between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media, perpendicular to the electrodes (the Z direction of FIG. 1 ), within each diffusion media is achieved, whereby the regions of micro-porous media may or may not be continuous (in contact) with the MPL.
Each diffusion media to which the MPL has been applied has, preferably, a higher through plane permeability (in the Z direction of FIG. 1 ) of the micro-porous media relative to in plane permeability (the XY plane of FIG. 1 ) of the micro-porous media to enhance penetration of the micro-porous media into each diffusion media relative to lateral dispersion (dispersion in the XY plane of FIG. 1 ) to the extent that the diffusion media substrate fiber orientation can be controlled thereby enhancing the non-uniformity of micro-porous media, perpendicular to the electrodes (the Z direction of FIG. 1 ) within each diffusion media.
The composition of micro-porous media creating the aforementioned MPL and regions of non-uniformity of micro-porous media are well known in the relevant art, as previously described. Techniques well known in the relevant art can also be used to adjust the composition of micro-porous media to affect the penetration (in the Z direction of FIG. 1 ) of the micro-porous media relative to in plane permeability (the XY plane of FIG. 1 ) of the micro-porous media to enhance penetration (in the Z direction of FIG. 1 ) of the micro-porous media into each diffusion media relative to lateral dispersion (dispersion in the XY plane of FIG. 1 ), thereby enhancing the non-uniformity of micro-porous media perpendicular to the electrodes (the Z direction of FIG. 1 ) within each diffusion media.
The aforementioned geometric pattern of micro-porous media creating the aforementioned multiplicity of regions of micro-porous media interposed between a multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied can be introduced into the diffusion media by, for example, screen printing with a mask containing the geometric pattern wherein the geometric pattern, the composition of the micro-porous media, and application pressure of the micro-porous media on the surface of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.
Alternatively, the aforementioned geometric pattern may be pierced into the aforementioned surface of the diffusion media using, for example, a mask containing the geometric pattern to allow preferential penetration (in the Z direction of FIG. 1 ) of the micro-porous media thereby creating the aforementioned multiplicity of regions of micro-porous media interposed between a multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied which can be introduced into the diffusion media by, for example, screen printing wherein the geometric pattern, the composition of the micro-porous media and application pressure of the micro-porous media on the surface of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.
The present invention ensures good water management of the diffusion media. The diffusion media and micro-porous media are, preferably, hydrophobic. The smaller pore size of the micro-porous media moves water to the larger pores of the diffusion media that does not contain micro-porous media and liquid water that is present in the larger pores of the diffusion media that does not contain micro-porous media cannot migrate to the smaller pores of the micro-porous media. Thus, the micro-porous media are relatively free or have a lower fraction of liquid water than the diffusion media without micro-porous media. Therefore, the micro-porous media comprising the continuous MPL functions as a check valve between the electrodes and diffusion media to ensure that water does not migrate back to the electrodes. Furthermore, the aforementioned multiplicity of regions of micro-porous media within each diffusion media to which the MPL has been applied provide conduits for gas passage to the electrodes while the multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied provide regions for excess water movement to the flowfield for expulsion from the fuel cell. Also, water within the diffusion media can form a film which would occur at the MPL-diffusion media interface, for example surfaces 106 and 114 of FIG. 1 . Such a water film, particularly if continuous, would significantly reduce transfer of reactant gases to the electrode and water to the flowfield and limit current production. The aforementioned non-uniformity of micro-porous media between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media, perpendicular to the electrodes (the Z direction of FIG. 1 ), within each diffusion media to which the MPL has been applied break through and disrupt the continuity of this water film thereby creating preferential channels for gas diffusion to the electrodes and water movement away from the electrodes to the flowfield for expulsion from the fuel cell. Hence, water management of the diffusion media is accomplished through pore size difference between micro-porous media and substrate, not by variations in surface properties of the MPL or diffusion media.
In a first preferred embodiment of the present invention, a continuous MPL, consisting of a micro-porous media, is applied to one surface on the electrode side of at least one or more diffusion media of a fuel cell wherein a geometric pattern, for example, dots or stripes, of micro-porous media is also introduced into the same surface of each diffusion media, for example surfaces 106 and 114 of FIG. 1 , to which the MPL is applied thereby forming a multiplicity of regions of micro-porous media interposed between a multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied wherein non-uniformity of micro-porous media between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media, perpendicular to the electrodes (the Z direction of FIG. 1 ), within each diffusion media is achieved whereby the regions of micro-porous media are continuous (in contact) with the MPL.
The geometric pattern of micro-porous media can be introduced into the diffusion media by, for example, screen printing a mask containing the geometric pattern wherein the geometric pattern, the composition of the micro-porous media, and application pressure of the micro-porous media on the surface of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.
Alternatively, the geometric pattern may be pierced into the surface of the diffusion media using, for example, a mask containing the geometric pattern to allow preferential penetration (in the Z direction of FIG. 1 ) of the micro-porous media which can be introduced into the diffusion media by, for example, screen printing wherein the geometric pattern, the composition of the micro-porous media and application pressure of the micro-porous media on the surface of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.
In a second preferred embodiment of the present invention, a continuous MPL, consisting of a micro-porous media, is applied to one surface on the electrode side of at least one or more diffusion media of a fuel cell wherein a geometric pattern, for example, dots or stripes, of micro-porous media is also introduced into the opposite surface (the flowfield side) of each diffusion media, for example surfaces on sides 122 and 124 (the flowfield sides) opposite to surfaces 106 and 114 (the electrode sides) of FIG. 1 , to which the MPL is applied, thereby forming a multiplicity of regions of micro-porous media interposed between a multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied wherein non-uniformity of micro-porous media between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media, perpendicular to the electrodes (the Z direction of FIG. 1 ), within each diffusion media is achieved, whereby the regions of micro-porous media may or may not be continuous (in contact) with the continuous MPL.
The geometric pattern of micro-porous media can be introduced into the diffusion media by, for example, screen printing a mask containing the geometric pattern wherein the geometric pattern, the composition of the micro-porous media, and application pressure of the micro-porous media on the surfaces of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.
Alternatively, the geometric pattern may be pierced into the surface of the diffusion media using, for example, a mask containing the geometric pattern to allow preferential penetration (in the Z direction of FIG. 1 ) of the micro-porous media which can be introduced into the diffusion media by, for example, screen printing wherein the geometric pattern, the composition of the micro-porous media and application pressure of the micro-porous media on the surface of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.
Many variations in the embodiments of present invention are contemplated as described herein in more detail. Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views.
FIG. 1 depicts a perspective, broken-away view of a fuel cell employing micro-porous layers which is known in the prior art.
FIG. 2 depicts a plan view of a portion of a mask containing a geometric hole pattern according to the present invention.
FIG. 3 is a sectional side view of an implementation of a first preferred embodiment according to the present invention.
FIG. 4 is a sectional side view of an implementation of a second preferred embodiment according to the present invention.
FIG. 5 is a plot comparing the performance of first through third fuel cells under wet conditions in accordance with the embodiments of FIGS. 3 and 4 .
FIG. 6 is a plot comparing the performance of the first through third fuel cells of FIG. 5 under dry conditions in accordance with the embodiments of FIGS. 3 and 4 .
FIG. 7 is a plot comparing the performance of fourth and fifth fuel cells under wet conditions in accordance with the embodiments of FIGS. 3 and 4 .
FIG. 8 is a plot comparing the performance of the fourth and fifth fuel cells of FIG. 7 under dry conditions in accordance with the embodiments of FIGS. 3 and 4 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 2 depicts a mask 200 containing a geometric hole pattern 202 utilized with the first and second preferred embodiments of the present invention wherein the hole size (diameter) 204 is 1/16 of an inch and the hole pitch 206 is ⅛ of an inch The hole size 204 and hole pitch 206 are empirically determined in accordance with the properties of the micro-porous media, the diffusion media, and application pressure of the micro-porous media on the surface of the diffusion media as previously described.
FIG. 3 is a first example 300 , utilizing the mask 200 of FIG. 2 , of an implementation of a first preferred embodiment according to the present invention. A continuous MPL 302 , consisting of a micro-porous media, is applied to one surface 304 on the electrode side 306 (opposite the flowfield side 318 ) of at least one or more diffusion media 308 of a fuel cell. A geometric dot pattern 310 of micro-porous media 310 a is also introduced into a multiplicity of regions 310 b in the same surface of each diffusion media to which the MPL is applied. Accordingly, provided is a multiplicity of regions of micro-porous media 312 interposed between a multiplicity of regions without micro-porous media 314 within each diffusion media to which the MPL has been applied. As a result, provided is non-uniformity of the micro-porous media 316 between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media within the diffusion media, perpendicular to the surfaces or electrodes (the Z direction), within each diffusion media. The regions of micro-porous media 310 b are continuous (in contact) with the MPL 302 at the surface 304 .
The geometric dot pattern 310 of micro-porous media 310 a can be introduced into the diffusion media 308 by, for example, the screen printing mask 200 , wherein the geometric hole pattern 202 thereof corresponds to the geometrical dot pattern 310 , and wherein the composition of the micro-porous media, and application pressure of the micro-porous media on the surface 304 of the diffusion media can be empirically adjusted to affect the penetration depth 316 (in the Z direction) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art. Alternatively, the aforementioned geometric dot pattern 310 may be provided by regions 310 b pierced into the aforementioned surface of the diffusion media using, for example, a mask containing the geometric pattern to allow preferential penetration (in the Z direction of FIG. 1 ) of the micro-porous media.
FIG. 4 is a second example 400 , utilizing the mask 200 of FIG. 2 , of an implementation of a second preferred embodiment according to the present invention. A continuous MPL 402 , consisting of a micro-porous media, is applied to one surface 404 on a surface at the electrode side 406 of at least one or more diffusion media 408 of a fuel cell. A geometric dot pattern 410 of micro-porous media 410 a is also introduced into a multiplicity of regions 410 b in the opposite surface 420 at the flowfield side 418 of each diffusion media to which the MPL is applied. Accordingly, provided is a multiplicity of regions of micro-porous media 412 interposed between a multiplicity of regions without micro-porous media 414 within each diffusion media to which the MPL has been applied. As a result, provided is non-uniformity of the micro-porous media 416 between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media, perpendicular to the surfaces or electrodes (the Z direction) within each diffusion media. The regions of micro-porous media 410 b may or may not be continuous (in contact) with the MPL at the surface 404 .
The geometric dot pattern 410 of micro-porous media 410 a can be introduced into the diffusion media 408 by, for example, the screen printing mask 200 , wherein the geometric hole pattern 202 thereof corresponds to the geometric dot pattern 410 , and wherein the composition of the micro-porous media, and application pressure of the micro-porous media on the surfaces 404 , 420 of the diffusion media can be empirically adjusted to affect the penetration depth 416 (in the Z direction) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art. Alternatively, the aforementioned geometric dot pattern 410 may be provided by regions 410 b pierced into the aforementioned surface of the diffusion media using, for example, a mask containing the geometric pattern to allow preferential penetration (in the Z direction of FIG. 1 ) of the micro-porous media.
Each fuel cell tested for FIGS. 5 through 8 used low density Toray (EXP003U) substrate with further micro-porous media treatment for the cathode diffusion media and Toray TGP 060 with 7 wt % PTFE (polytetrafluoroethylene) always for the anode diffusion media. General Motors micro-porous media formulation was introduced into the cathode diffusion media of each fuel cell as described in U.S. patent application Ser. No. 10/925,853, filed Aug. 25, 2004, the disclosure of which is hereby herein incorporated by reference, rather than the anode diffusion media, wherein the MPL of each fuel cell of FIGS. 5 and 6 utilized General Motors micro-porous media formulation on the surface of the cathode media on the cathode electrode side and each fuel cell of FIGS. 7 and 8 utilized Carbel MP30Z from Gore, a free-standing MPL, as the continuous MPL layer on the surface of the cathode media on the cathode electrode side, whereby a first preferred embodiment example and a second preferred embodiment example of the present invention was implemented in FIGS. 5 through 8 . It is the be appreciated, as previously described, that results similar to FIGS. 5 through 8 could also be obtained by the utilization of other commercial micro-porous media produced by, for example, SGL Carbon (SGL). Results of measurements using high frequency resistance (HFR) techniques for measuring the electrical and ionic resistance of fuel cells, well known in the relevant art, are also displayed for each fuel cell in FIGS. 5 through 8 .
Each fuel cell of FIGS. 5 and 7 was operated at 270 KPa absolute outlet pressure and a wet condition of 300% relative humidity of the outlet stream while each fuel cell of FIGS. 6 and 8 was operated at 100 KPa absolute outlet pressure and a dry condition of 84% relative humidity of the outlet stream. Outlet pressure parameters as well as the terms “wet” and “dry” are terminologies used and well understood by those in the relevant art.
Referring now to FIG. 5 , plot 500 compares the performance of first through third fuel cells under wet conditions in accordance with the embodiments of FIGS. 3 and 4 . Curves 502 , 504 , 506 of the first through third fuel cells, respectively, are associated with the voltage axis while curves 502 ′, 504 ′, 506 ′ of the first through third fuel cells, respectively, are associated with the HFR axis.
The first fuel cell of curves 502 , 502 ′ utilized micro-porous media only on an MPL on the surface of the cathode diffusion media on the cathode electrode side and is utilized as a base line for comparison. The second fuel cell of curves 504 , 504 ′ utilized micro-porous media in accordance with FIG. 3 on the cathode diffusion media implementing the first preferred embodiment of the present invention. The third fuel cell of curves 506 , 506 ′ utilized micro-porous media in accordance with FIG. 4 on the cathode diffusion media implementing the second preferred embodiment of the present invention.
It can be seen in FIG. 5 that the second fuel cell of curve 504 implementing a first preferred embodiment of the present invention has a better performance than a first fuel cell of curve 502 , whereby the voltage is higher for a given current for curve 504 compared to curve 502 , as exemplified at points 508 , 510 , under wet conditions.
Referring now to FIG. 6 , plot 600 compares the performance of the first through third fuel cells of FIG. 5 under dry conditions in accordance with the embodiments of FIGS. 3 and 4 . Curves 602 , 604 , 606 of the first through third fuel cells, respectively, are associated with the voltage axis while curves 602 ′, 604 ′, 606 ′ of the first through third fuel cells, respectively, are associated with the HFR axis.
It can be seen in FIG. 6 that the third fuel cell of curve 606 implementing the second preferred embodiment of the present invention has a better performance than a first fuel cell of curve 602 , whereby the voltage is higher for a given current for curve 606 compared to curve 602 and whereby the HFR is lower for a given current for curve 606 ′ compared to curve 602 ′, as exemplified at points 608 ′, 610 ′, under dry conditions.
Referring now to FIG. 7 , plot 700 compares the performance of fourth and fifth fuel cells under wet conditions in accordance with the embodiments of FIGS. 3 and 4 . Curves 704 , 706 of the fourth and fifth fuel cells, respectively, are associated with the voltage axis while curves 704 ′, 706 ′ of the fourth and fifth fuel cells, respectively, are associated with the HFR axis.
The fourth fuel cell of curves 704 , 704 ′ utilized micro-porous media in accordance with FIG. 3 on the cathode diffusion media implementing the first preferred embodiment of the present invention. The fifth fuel cell of curves 706 , 706 ′ utilized micro-porous media in accordance with FIG. 4 on the cathode diffusion media implementing the second preferred embodiment of the present invention.
In FIG. 7 , the fourth fuel cell of curve 704 implementing a first preferred embodiment of the present invention has a better performance, exemplified by points 708 , 710 , than a base line fuel cell (not shown) utilizing only a free-standing MPL (Carbel MP30Z from Gore) on the surface of the cathode media on the cathode electrode side, wherein the performance of the base line fuel cell utilizing only a free-standing MPL (Carbel MP30Z from Gore) on the surface of the cathode media on the cathode electrode side is well known in the relevant art and would reach a maximum current density of, approximately, 0.4 to 1.0 A/cm 2 at 0.5 V under wet conditions.
Referring now to FIG. 8 , plot 800 compares the performance of the fourth and fifth fuel cells of FIG. 7 under dry conditions in accordance with the embodiments of FIGS. 3 and 4 . Curves 804 , 806 of the fourth and fifth fuel cells, respectively, are associated with the voltage axis while curves 804 ′, 806 ′ of the fourth and fifth fuel cells, respectively, are associated with the HFR axis.
In FIG. 8 , the fifth fuel cell of curve 806 implementing the second preferred embodiment of the present invention has a better performance, whereby the voltage is higher for a given current for curve 806 and whereby the HFR is lower for a given current for curve 806 ′, as exemplified at points 808 ′, 810 ′, under dry conditions than a baseline fuel cell (not shown) utilizing only a free-standing MPL (Carbel MP30Z from Gore) on the surface of the cathode media on the cathode electrode side, wherein the performance of the base line fuel cell utilizing only a free-standing MPL (Carbel MP30Z from Gore) on the surface of the cathode media on the cathode electrode side is well known in the art under dry conditions and is similar to curve 804 .
It is to be noted that, conventionally, as the diffusion media is highly porous, the micro-porous media comprising the MPL typically penetrates into the surface 304 , 404 of the diffusion media immediately adjacent the MPL-diffusion media interface to a depth (in the Z direction of FIGS. 3 , 4 ) with respect to the surface of approximately 10 to 100 micrometers. The penetration is of the whole MPL layer sinking into the diffusion media, which depends on the micro-porous media formulation and porosity of the diffusion media substrate. The fibers comprising the diffusion media, typically, do not move, but the micro-porous media comprising the MPL flows around the fibers comprising the diffusion media. In contrast according to the present invention, screen printing or piercing through a mask with a geometric pattern are examples of methods wherein non-uniformity of micro-porous media within a diffusion media is achieved, as previously described, wherein the range of penetration (in the Z direction of FIGS. 3 , 4 ) of the micro-porous media 310 a , 410 a is approximately 50 to 200 micrometers. In the present invention, only a portion, per the geometric pattern, of the MPL is allowed to sink into the diffusion media. In this regard, control of where and how the MPL sinks into the diffusion media is achieved such that a non-uniform interface is provided therebetween which prevents the formation of a continuous liquid water film.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law. | A diffusion media and micro-porous media combination for a fuel cell. A diffusion layer is composed of a diffusion media and has a first (electrode) side and an opposite second (flowfield) side, wherein at least one of the first and second sides has a geometric pattern formed therein comprising a multiplicity of mutually spaced apart regions. A micro-porous media fills the multiplicity of regions and a micro-porous layer composed of the micro-porous media is continuously applied to the first surface. | Briefly outline the background technology and the problem the invention aims to solve. | [
"TECHNICAL FIELD The present invention relates to fuel cells and, more particularly, to micro-porous layers incorporating non-uniformity of micro-porous media within diffusion media of fuel cells.",
"BACKGROUND OF THE INVENTION Electrochemical fuel cells convert fuel and oxidant to electricity and reaction product.",
"Solid polymer electrochemical fuel cells generally employ a membrane electrode assembly (“MEA”) comprising a solid polymer electrolyte or ion exchange membrane disposed between two planar electrode diffusion layers or substrates (diffusion media) formed of porous, electrically conductive sheet material, such as carbon fiber paper or carbon cloth.",
"Suitable carbon fiber paper sheet material is available, for example, from Toray Industries, Inc. with grade designations such as TGP090, TGP060 and TGP030 having thicknesses of 0.27 mm, 0.19 mm and 0.10 mm, respectively, and a porosity of approximately 70%.",
"Carbon fiber paper sheet material is also available in other thicknesses and porosities.",
"Typically, the structure of the electrode substrate is substantially uniform, on a macroscopic scale, as it is traversed in plane (parallel to the planar major surfaces of the electrode substrate, i.e. the XY plane of FIG. 1 ) at any depth.",
"The MEA contains a layer of electrocatalyst, typically in the form of finely comminuted platinum, at each membrane/electrode substrate interface to induce the desired electrochemical reaction.",
"The electrodes are electrically coupled to provide a path for conducting electrons between the electrodes through an external load.",
"At the anode, the fuel stream moves through the porous anode substrate (anode diffusion media) and is oxidized at the anode electrocatalyst layer.",
"At the cathode, the oxidant stream moves through the porous cathode substrate (cathode diffusion media) and is reduced at the cathode electrocatalyst layer to form a reaction product.",
"In electrochemical fuel cells employing hydrogen as the fuel and oxygen-containing air (or substantially pure oxygen) as the oxidant, the catalyzed reaction at the anode produces hydrogen cations (protons) from the fuel supply.",
"The ion exchange membrane facilitates the migration of protons from the anode to the cathode.",
"In addition to conducting protons, the membrane isolates the hydrogen-containing fuel stream from the oxygen-containing oxidant stream.",
"At the cathode electrocatalyst layer, oxygen reacts with the protons that have crossed the membrane to form water as the reaction product.",
"In electrochemical fuel cells, the MEA is typically interposed between two fluid flowfield plates (anode and cathode plates).",
"The plates act as current collectors, provide support to the MEA, provide means for access of the fuel and oxidant to the anode and cathode surfaces, respectively, and provide for the removal of water formed during operation of the cells.",
"As the oxidant stream travels through the fluid flow channels typically formed in the fluid flowfield plates of the cell, the stream transports water passing through the cathode diffusion media that is produced as the product of the electrochemical reaction.",
"The water is transported either as water vapor or as entrained water droplets.",
"As a result, the portion of the flowfield into which the oxidant stream is introduced and through which the oxidant stream initially flows is drier than the portion of the flowfield through which the oxidant stream flows just prior to being exhausted from the fuel cell.",
"In the latter portion of the oxidant flowfield, the oxidant stream can become saturated with water, in which case two phase flow occurs, that is, the oxidant stream contains water vapor and also has liquid water entrained in the stream.",
"Wet and dry regions of the flowfield can detrimentally affect fuel cell performance and accelerate the degradation of performance over time.",
"Fuel cell performance is defined as the voltage output from the cell for a given current density;",
"the higher the voltage for a given current density, the better.",
"Control of water transport perpendicular to the plane of the electrodes (the Z direction of FIG. 1 ) away from the cathode to the oxidant flowfield;",
"that is, movement of water in the direction from the cathode electrocatalyst layer to the oxidant flow channels (the “free stream”), is important to optimizing fuel cell performance.",
"The “free stream”",
"is the fluid stream within the reactant distribution channels.",
"In addition to the control of water transport, control of oxidant transport in the direction from the oxidant flow channels or free stream to the cathode electrocatalyst layer, is important to optimizing fuel cell performance.",
"The concentration of oxygen at the electrocatalyst layer directly affects, fuel cell performance because oxygen concentration affects the rate of the electrochemical reaction.",
"The diffusion media serve several functions.",
"One of these functions is the diffusion of reactant gases therethrough for reacting, within the respective catalyst layer.",
"Another is to diffuse reaction products, namely water, away from the catalyst layer.",
"Additionally, the diffusion media must conduct electrons and heat between the catalyst layers and flowfield plates.",
"The water generated by the electrochemical reaction on the catalytic layer on the cathode side mostly leaves the electrode as a vapor and condenses in the cathode diffusion media.",
"If the condensed water remains around the catalytic layer, the oxygen gas is prevented from reaching the reaction area and cell performance is lowered.",
"Avoiding a continuous water film in reactant gas pathways is critical to maintaining fuel cell performance.",
"To solve these problems, various countermeasures have been proposed and tried in the prior art, which include the use of a surface layer or layers on the diffusion media.",
"A micro-porous layer (MPL), well known in the art, consisting of carbon or graphite particles mixed with a polymeric binder is the most common surface layer applied to the surfaces of diffusion media.",
"An MPL has, typically, a pore size between 100 nanometers and 500 nanometers whereas diffusion media, typically, have pore sizes between 10 micrometers and 30 micrometers.",
"Thus, the pore size of an MPL is smaller than the pore sizes of the diffusion media on which it is applied.",
"This is one reason, among others, that an MPL provides an effective way to remove product water from the electrode.",
"It also may reduce electrical contact resistance with the adjacent catalyst layer.",
"An MPL may be applied to a surface of a diffusion media by, for example, screen printing, knife coating, and spraying, and is usually tailored, for example, empirically, to provide a surface coating of desired thickness with the given application technique.",
"A commercial example of an MPL is known as Electrode Los Alamos Type produced by DeNora North America, Etek Division.",
"Micro-porous layers are also described in various literature, for example, “Handbook of Fuel Cells—Fundamentals, Technology, and Applications”, edited by Wolf Vielstich, Hubert Gasteiger, Arnold Lamm, Volume 3, “Fuel Cell Technology and Applications”, Chapter 46, copyright 2003 John Wiley and Sons, Ltd. It is pointed out that if the diffusion media are given a hydrophilic treatment, the cell performance will drop because the hydrophilic treatment would inhibit transfer of excess water to the flowfield for ultimate removal from the fuel cell.",
"FIG. 1 depicts a typical prior art subsection 100 of a fuel cell employing a first MPL 102 adjacent to an anode catalyst 104 on the surface 106 of an anode diffusion media 108 and a second MPL 110 adjacent to a cathode catalyst 112 on the surface 114 of a cathode diffusion media 116 , wherein 118 is the solid polymer electrolyte or ion exchange membrane.",
"The MEA 120 , typically, consists of, collectively, elements 104 , 118 , and 112 .",
"Other methods have also been proposed to remove water from the catalyst layers, especially on the cathode side, such as placing holes in the diffusion media and embossing a pattern onto the diffusion media.",
"Placing holes in an MPL having a uniform thickness perpendicular to the plane of the electrodes (the Z direction of FIG. 1 ) and a pattern of hydrophobic treatment on hydrophilic diffusion media have also been proposed.",
"U.S. Pat. Nos. 5,840,438, 6,117,579, 6,521,369, and 6,579,639 exemplify these methods.",
"However, placing holes in an MPL or the diffusion media or embossing the diffusion media compromise the mechanical, electrical and thermal integrity of the diffusion media.",
"Hydrophilic treatments of the diffusion, media would inhibit transfer of excess water to the flowfield for ultimate removal from the cell.",
"In addition, by situating a MPL having a sharp interface with the substrate perpendicular to the plane of the electrodes (the Z direction of FIG. 1 ), water within the diffusion media can form a film at the MPL-substrate interface, for example surfaces 106 and 114 of FIG. 1 .",
"Such a film, particularly if continuous, would significantly reduce transfer of reactant gases and reduce the limiting current.",
"Accordingly, what is needed in the art is a method providing better management of reactant gases and water within fuel cells.",
"SUMMARY OF THE INVENTION The present invention is a continuous MPL, consisting of a micro-porous media, applied to one surface on the electrode side of at least one or more diffusion media of a fuel cell, wherein a geometric pattern, for example, dots or stripes, of micro-porous media is also introduced into each diffusion media to which the MPL has been applied.",
"Accordingly, provided by the geometric pattern is a multiplicity of regions of micro-porous media interposed between a multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied wherein non-uniformity of micro-porous media between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media, perpendicular to the electrodes (the Z direction of FIG. 1 ), within each diffusion media is achieved, whereby the regions of micro-porous media may or may not be continuous (in contact) with the MPL.",
"Each diffusion media to which the MPL has been applied has, preferably, a higher through plane permeability (in the Z direction of FIG. 1 ) of the micro-porous media relative to in plane permeability (the XY plane of FIG. 1 ) of the micro-porous media to enhance penetration of the micro-porous media into each diffusion media relative to lateral dispersion (dispersion in the XY plane of FIG. 1 ) to the extent that the diffusion media substrate fiber orientation can be controlled thereby enhancing the non-uniformity of micro-porous media, perpendicular to the electrodes (the Z direction of FIG. 1 ) within each diffusion media.",
"The composition of micro-porous media creating the aforementioned MPL and regions of non-uniformity of micro-porous media are well known in the relevant art, as previously described.",
"Techniques well known in the relevant art can also be used to adjust the composition of micro-porous media to affect the penetration (in the Z direction of FIG. 1 ) of the micro-porous media relative to in plane permeability (the XY plane of FIG. 1 ) of the micro-porous media to enhance penetration (in the Z direction of FIG. 1 ) of the micro-porous media into each diffusion media relative to lateral dispersion (dispersion in the XY plane of FIG. 1 ), thereby enhancing the non-uniformity of micro-porous media perpendicular to the electrodes (the Z direction of FIG. 1 ) within each diffusion media.",
"The aforementioned geometric pattern of micro-porous media creating the aforementioned multiplicity of regions of micro-porous media interposed between a multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied can be introduced into the diffusion media by, for example, screen printing with a mask containing the geometric pattern wherein the geometric pattern, the composition of the micro-porous media, and application pressure of the micro-porous media on the surface of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.",
"Alternatively, the aforementioned geometric pattern may be pierced into the aforementioned surface of the diffusion media using, for example, a mask containing the geometric pattern to allow preferential penetration (in the Z direction of FIG. 1 ) of the micro-porous media thereby creating the aforementioned multiplicity of regions of micro-porous media interposed between a multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied which can be introduced into the diffusion media by, for example, screen printing wherein the geometric pattern, the composition of the micro-porous media and application pressure of the micro-porous media on the surface of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.",
"The present invention ensures good water management of the diffusion media.",
"The diffusion media and micro-porous media are, preferably, hydrophobic.",
"The smaller pore size of the micro-porous media moves water to the larger pores of the diffusion media that does not contain micro-porous media and liquid water that is present in the larger pores of the diffusion media that does not contain micro-porous media cannot migrate to the smaller pores of the micro-porous media.",
"Thus, the micro-porous media are relatively free or have a lower fraction of liquid water than the diffusion media without micro-porous media.",
"Therefore, the micro-porous media comprising the continuous MPL functions as a check valve between the electrodes and diffusion media to ensure that water does not migrate back to the electrodes.",
"Furthermore, the aforementioned multiplicity of regions of micro-porous media within each diffusion media to which the MPL has been applied provide conduits for gas passage to the electrodes while the multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied provide regions for excess water movement to the flowfield for expulsion from the fuel cell.",
"Also, water within the diffusion media can form a film which would occur at the MPL-diffusion media interface, for example surfaces 106 and 114 of FIG. 1 .",
"Such a water film, particularly if continuous, would significantly reduce transfer of reactant gases to the electrode and water to the flowfield and limit current production.",
"The aforementioned non-uniformity of micro-porous media between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media, perpendicular to the electrodes (the Z direction of FIG. 1 ), within each diffusion media to which the MPL has been applied break through and disrupt the continuity of this water film thereby creating preferential channels for gas diffusion to the electrodes and water movement away from the electrodes to the flowfield for expulsion from the fuel cell.",
"Hence, water management of the diffusion media is accomplished through pore size difference between micro-porous media and substrate, not by variations in surface properties of the MPL or diffusion media.",
"In a first preferred embodiment of the present invention, a continuous MPL, consisting of a micro-porous media, is applied to one surface on the electrode side of at least one or more diffusion media of a fuel cell wherein a geometric pattern, for example, dots or stripes, of micro-porous media is also introduced into the same surface of each diffusion media, for example surfaces 106 and 114 of FIG. 1 , to which the MPL is applied thereby forming a multiplicity of regions of micro-porous media interposed between a multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied wherein non-uniformity of micro-porous media between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media, perpendicular to the electrodes (the Z direction of FIG. 1 ), within each diffusion media is achieved whereby the regions of micro-porous media are continuous (in contact) with the MPL.",
"The geometric pattern of micro-porous media can be introduced into the diffusion media by, for example, screen printing a mask containing the geometric pattern wherein the geometric pattern, the composition of the micro-porous media, and application pressure of the micro-porous media on the surface of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.",
"Alternatively, the geometric pattern may be pierced into the surface of the diffusion media using, for example, a mask containing the geometric pattern to allow preferential penetration (in the Z direction of FIG. 1 ) of the micro-porous media which can be introduced into the diffusion media by, for example, screen printing wherein the geometric pattern, the composition of the micro-porous media and application pressure of the micro-porous media on the surface of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.",
"In a second preferred embodiment of the present invention, a continuous MPL, consisting of a micro-porous media, is applied to one surface on the electrode side of at least one or more diffusion media of a fuel cell wherein a geometric pattern, for example, dots or stripes, of micro-porous media is also introduced into the opposite surface (the flowfield side) of each diffusion media, for example surfaces on sides 122 and 124 (the flowfield sides) opposite to surfaces 106 and 114 (the electrode sides) of FIG. 1 , to which the MPL is applied, thereby forming a multiplicity of regions of micro-porous media interposed between a multiplicity of regions without micro-porous media within each diffusion media to which the MPL has been applied wherein non-uniformity of micro-porous media between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media, perpendicular to the electrodes (the Z direction of FIG. 1 ), within each diffusion media is achieved, whereby the regions of micro-porous media may or may not be continuous (in contact) with the continuous MPL.",
"The geometric pattern of micro-porous media can be introduced into the diffusion media by, for example, screen printing a mask containing the geometric pattern wherein the geometric pattern, the composition of the micro-porous media, and application pressure of the micro-porous media on the surfaces of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.",
"Alternatively, the geometric pattern may be pierced into the surface of the diffusion media using, for example, a mask containing the geometric pattern to allow preferential penetration (in the Z direction of FIG. 1 ) of the micro-porous media which can be introduced into the diffusion media by, for example, screen printing wherein the geometric pattern, the composition of the micro-porous media and application pressure of the micro-porous media on the surface of the diffusion media can be empirically adjusted to affect the penetration depth (in the Z direction of FIG. 1 ) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.",
"Many variations in the embodiments of present invention are contemplated as described herein in more detail.",
"Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.",
"BRIEF DESCRIPTION OF THE DRAWING The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views.",
"FIG. 1 depicts a perspective, broken-away view of a fuel cell employing micro-porous layers which is known in the prior art.",
"FIG. 2 depicts a plan view of a portion of a mask containing a geometric hole pattern according to the present invention.",
"FIG. 3 is a sectional side view of an implementation of a first preferred embodiment according to the present invention.",
"FIG. 4 is a sectional side view of an implementation of a second preferred embodiment according to the present invention.",
"FIG. 5 is a plot comparing the performance of first through third fuel cells under wet conditions in accordance with the embodiments of FIGS. 3 and 4 .",
"FIG. 6 is a plot comparing the performance of the first through third fuel cells of FIG. 5 under dry conditions in accordance with the embodiments of FIGS. 3 and 4 .",
"FIG. 7 is a plot comparing the performance of fourth and fifth fuel cells under wet conditions in accordance with the embodiments of FIGS. 3 and 4 .",
"FIG. 8 is a plot comparing the performance of the fourth and fifth fuel cells of FIG. 7 under dry conditions in accordance with the embodiments of FIGS. 3 and 4 .",
"DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 2 depicts a mask 200 containing a geometric hole pattern 202 utilized with the first and second preferred embodiments of the present invention wherein the hole size (diameter) 204 is 1/16 of an inch and the hole pitch 206 is ⅛ of an inch The hole size 204 and hole pitch 206 are empirically determined in accordance with the properties of the micro-porous media, the diffusion media, and application pressure of the micro-porous media on the surface of the diffusion media as previously described.",
"FIG. 3 is a first example 300 , utilizing the mask 200 of FIG. 2 , of an implementation of a first preferred embodiment according to the present invention.",
"A continuous MPL 302 , consisting of a micro-porous media, is applied to one surface 304 on the electrode side 306 (opposite the flowfield side 318 ) of at least one or more diffusion media 308 of a fuel cell.",
"A geometric dot pattern 310 of micro-porous media 310 a is also introduced into a multiplicity of regions 310 b in the same surface of each diffusion media to which the MPL is applied.",
"Accordingly, provided is a multiplicity of regions of micro-porous media 312 interposed between a multiplicity of regions without micro-porous media 314 within each diffusion media to which the MPL has been applied.",
"As a result, provided is non-uniformity of the micro-porous media 316 between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media within the diffusion media, perpendicular to the surfaces or electrodes (the Z direction), within each diffusion media.",
"The regions of micro-porous media 310 b are continuous (in contact) with the MPL 302 at the surface 304 .",
"The geometric dot pattern 310 of micro-porous media 310 a can be introduced into the diffusion media 308 by, for example, the screen printing mask 200 , wherein the geometric hole pattern 202 thereof corresponds to the geometrical dot pattern 310 , and wherein the composition of the micro-porous media, and application pressure of the micro-porous media on the surface 304 of the diffusion media can be empirically adjusted to affect the penetration depth 316 (in the Z direction) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.",
"Alternatively, the aforementioned geometric dot pattern 310 may be provided by regions 310 b pierced into the aforementioned surface of the diffusion media using, for example, a mask containing the geometric pattern to allow preferential penetration (in the Z direction of FIG. 1 ) of the micro-porous media.",
"FIG. 4 is a second example 400 , utilizing the mask 200 of FIG. 2 , of an implementation of a second preferred embodiment according to the present invention.",
"A continuous MPL 402 , consisting of a micro-porous media, is applied to one surface 404 on a surface at the electrode side 406 of at least one or more diffusion media 408 of a fuel cell.",
"A geometric dot pattern 410 of micro-porous media 410 a is also introduced into a multiplicity of regions 410 b in the opposite surface 420 at the flowfield side 418 of each diffusion media to which the MPL is applied.",
"Accordingly, provided is a multiplicity of regions of micro-porous media 412 interposed between a multiplicity of regions without micro-porous media 414 within each diffusion media to which the MPL has been applied.",
"As a result, provided is non-uniformity of the micro-porous media 416 between the multiplicity of regions of micro-porous media and the multiplicity of regions without micro-porous media, perpendicular to the surfaces or electrodes (the Z direction) within each diffusion media.",
"The regions of micro-porous media 410 b may or may not be continuous (in contact) with the MPL at the surface 404 .",
"The geometric dot pattern 410 of micro-porous media 410 a can be introduced into the diffusion media 408 by, for example, the screen printing mask 200 , wherein the geometric hole pattern 202 thereof corresponds to the geometric dot pattern 410 , and wherein the composition of the micro-porous media, and application pressure of the micro-porous media on the surfaces 404 , 420 of the diffusion media can be empirically adjusted to affect the penetration depth 416 (in the Z direction) of the micro-porous media into the diffusion media such that desired performance of water management of the diffusion media is achieved, as empirically determined by techniques well known in the relevant art.",
"Alternatively, the aforementioned geometric dot pattern 410 may be provided by regions 410 b pierced into the aforementioned surface of the diffusion media using, for example, a mask containing the geometric pattern to allow preferential penetration (in the Z direction of FIG. 1 ) of the micro-porous media.",
"Each fuel cell tested for FIGS. 5 through 8 used low density Toray (EXP003U) substrate with further micro-porous media treatment for the cathode diffusion media and Toray TGP 060 with 7 wt % PTFE (polytetrafluoroethylene) always for the anode diffusion media.",
"General Motors micro-porous media formulation was introduced into the cathode diffusion media of each fuel cell as described in U.S. patent application Ser.",
"No. 10/925,853, filed Aug. 25, 2004, the disclosure of which is hereby herein incorporated by reference, rather than the anode diffusion media, wherein the MPL of each fuel cell of FIGS. 5 and 6 utilized General Motors micro-porous media formulation on the surface of the cathode media on the cathode electrode side and each fuel cell of FIGS. 7 and 8 utilized Carbel MP30Z from Gore, a free-standing MPL, as the continuous MPL layer on the surface of the cathode media on the cathode electrode side, whereby a first preferred embodiment example and a second preferred embodiment example of the present invention was implemented in FIGS. 5 through 8 .",
"It is the be appreciated, as previously described, that results similar to FIGS. 5 through 8 could also be obtained by the utilization of other commercial micro-porous media produced by, for example, SGL Carbon (SGL).",
"Results of measurements using high frequency resistance (HFR) techniques for measuring the electrical and ionic resistance of fuel cells, well known in the relevant art, are also displayed for each fuel cell in FIGS. 5 through 8 .",
"Each fuel cell of FIGS. 5 and 7 was operated at 270 KPa absolute outlet pressure and a wet condition of 300% relative humidity of the outlet stream while each fuel cell of FIGS. 6 and 8 was operated at 100 KPa absolute outlet pressure and a dry condition of 84% relative humidity of the outlet stream.",
"Outlet pressure parameters as well as the terms “wet”",
"and “dry”",
"are terminologies used and well understood by those in the relevant art.",
"Referring now to FIG. 5 , plot 500 compares the performance of first through third fuel cells under wet conditions in accordance with the embodiments of FIGS. 3 and 4 .",
"Curves 502 , 504 , 506 of the first through third fuel cells, respectively, are associated with the voltage axis while curves 502 ′, 504 ′, 506 ′ of the first through third fuel cells, respectively, are associated with the HFR axis.",
"The first fuel cell of curves 502 , 502 ′ utilized micro-porous media only on an MPL on the surface of the cathode diffusion media on the cathode electrode side and is utilized as a base line for comparison.",
"The second fuel cell of curves 504 , 504 ′ utilized micro-porous media in accordance with FIG. 3 on the cathode diffusion media implementing the first preferred embodiment of the present invention.",
"The third fuel cell of curves 506 , 506 ′ utilized micro-porous media in accordance with FIG. 4 on the cathode diffusion media implementing the second preferred embodiment of the present invention.",
"It can be seen in FIG. 5 that the second fuel cell of curve 504 implementing a first preferred embodiment of the present invention has a better performance than a first fuel cell of curve 502 , whereby the voltage is higher for a given current for curve 504 compared to curve 502 , as exemplified at points 508 , 510 , under wet conditions.",
"Referring now to FIG. 6 , plot 600 compares the performance of the first through third fuel cells of FIG. 5 under dry conditions in accordance with the embodiments of FIGS. 3 and 4 .",
"Curves 602 , 604 , 606 of the first through third fuel cells, respectively, are associated with the voltage axis while curves 602 ′, 604 ′, 606 ′ of the first through third fuel cells, respectively, are associated with the HFR axis.",
"It can be seen in FIG. 6 that the third fuel cell of curve 606 implementing the second preferred embodiment of the present invention has a better performance than a first fuel cell of curve 602 , whereby the voltage is higher for a given current for curve 606 compared to curve 602 and whereby the HFR is lower for a given current for curve 606 ′ compared to curve 602 ′, as exemplified at points 608 ′, 610 ′, under dry conditions.",
"Referring now to FIG. 7 , plot 700 compares the performance of fourth and fifth fuel cells under wet conditions in accordance with the embodiments of FIGS. 3 and 4 .",
"Curves 704 , 706 of the fourth and fifth fuel cells, respectively, are associated with the voltage axis while curves 704 ′, 706 ′ of the fourth and fifth fuel cells, respectively, are associated with the HFR axis.",
"The fourth fuel cell of curves 704 , 704 ′ utilized micro-porous media in accordance with FIG. 3 on the cathode diffusion media implementing the first preferred embodiment of the present invention.",
"The fifth fuel cell of curves 706 , 706 ′ utilized micro-porous media in accordance with FIG. 4 on the cathode diffusion media implementing the second preferred embodiment of the present invention.",
"In FIG. 7 , the fourth fuel cell of curve 704 implementing a first preferred embodiment of the present invention has a better performance, exemplified by points 708 , 710 , than a base line fuel cell (not shown) utilizing only a free-standing MPL (Carbel MP30Z from Gore) on the surface of the cathode media on the cathode electrode side, wherein the performance of the base line fuel cell utilizing only a free-standing MPL (Carbel MP30Z from Gore) on the surface of the cathode media on the cathode electrode side is well known in the relevant art and would reach a maximum current density of, approximately, 0.4 to 1.0 A/cm 2 at 0.5 V under wet conditions.",
"Referring now to FIG. 8 , plot 800 compares the performance of the fourth and fifth fuel cells of FIG. 7 under dry conditions in accordance with the embodiments of FIGS. 3 and 4 .",
"Curves 804 , 806 of the fourth and fifth fuel cells, respectively, are associated with the voltage axis while curves 804 ′, 806 ′ of the fourth and fifth fuel cells, respectively, are associated with the HFR axis.",
"In FIG. 8 , the fifth fuel cell of curve 806 implementing the second preferred embodiment of the present invention has a better performance, whereby the voltage is higher for a given current for curve 806 and whereby the HFR is lower for a given current for curve 806 ′, as exemplified at points 808 ′, 810 ′, under dry conditions than a baseline fuel cell (not shown) utilizing only a free-standing MPL (Carbel MP30Z from Gore) on the surface of the cathode media on the cathode electrode side, wherein the performance of the base line fuel cell utilizing only a free-standing MPL (Carbel MP30Z from Gore) on the surface of the cathode media on the cathode electrode side is well known in the art under dry conditions and is similar to curve 804 .",
"It is to be noted that, conventionally, as the diffusion media is highly porous, the micro-porous media comprising the MPL typically penetrates into the surface 304 , 404 of the diffusion media immediately adjacent the MPL-diffusion media interface to a depth (in the Z direction of FIGS. 3 , 4 ) with respect to the surface of approximately 10 to 100 micrometers.",
"The penetration is of the whole MPL layer sinking into the diffusion media, which depends on the micro-porous media formulation and porosity of the diffusion media substrate.",
"The fibers comprising the diffusion media, typically, do not move, but the micro-porous media comprising the MPL flows around the fibers comprising the diffusion media.",
"In contrast according to the present invention, screen printing or piercing through a mask with a geometric pattern are examples of methods wherein non-uniformity of micro-porous media within a diffusion media is achieved, as previously described, wherein the range of penetration (in the Z direction of FIGS. 3 , 4 ) of the micro-porous media 310 a , 410 a is approximately 50 to 200 micrometers.",
"In the present invention, only a portion, per the geometric pattern, of the MPL is allowed to sink into the diffusion media.",
"In this regard, control of where and how the MPL sinks into the diffusion media is achieved such that a non-uniform interface is provided therebetween which prevents the formation of a continuous liquid water film.",
"While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law."
] |
This patent application is a continuation and claims priority benefit of U.S. patent application Ser. No. 13/763,729 filed on Feb. 10, 2013,
wherein the Ser. No. 13/763,729 is the continuation and claims priority benefit of Ser. No. 11/931,026 filed on Oct. 31, 2007 and issued as U.S. Pat. No. 8,374,075, wherein the Ser. No. 11/931,026 is the continuation-in-part and claims priority benefit of international application No. PCT/CA2006/001120 filed on 27 Jun. 2006, wherein the Ser. No. 13/763,729 and the Ser. No. 11/931,026 applications are each hereby incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to providing low cost high accuracy phase and frequency recovery techniques (PFRT) offering significantly better stability and accuracy in synchronizing systems and circuits in multiple fields including communication systems, distributed control, test and measurement equipment, and automatic test equipment.
Such PFRT comprises software controlled clock synchronizer (SCCS) which can be used in multiple fields exemplified above wherein said communication systems include communication networks for wireless or wireline or optical transmissions with very wide ranges of data rates.
The SCCS comprises further novel components such as; programmable phase synthesizers (PS), precision frame phase detectors (FPD) of an incoming wave-form, and noise filtering edge detectors (NFED) for precise recovering of wave-form edges from noisy signals.
Furthermore: since said FPD and NFED define circuits and methods enabling ˜10 times faster and more accurate location systems than conventional solutions, they allow reliable location services for mobile and traffic control applications including fast movements at close ranges in noisy environments unacceptable for solutions.
Still furthermore this invention comprises receiver synchronization techniques (RST), utilizing a referencing frame, recovered from an OFDM composite signal, for synchronizing an OFDM receiver clock to a composite signal transmitter clock.
2. Background Art of Software Controlled Clock Synchronizer
Conventional solutions for software controlled synchronization systems use software controlled digital phase locked loops (DPLLs) for implementing software algorithm minimizing phase errors and providing programmed transfer function between a DPLL output clock and a timing reference.
In conventional solutions said timing reference can be provided:
as a conventional external clock connected to a digital phase detector, which compares it with the local clock in order to produce the digital phase error; or with time stamp messages sent by an external source, initiating a capture of local clock time and communicating external clock timing corresponding to the captured local timing, wherein software is used for producing said digital phase errors by comparing the captured local timing with the communicated external timing.
However the conventional DPLL configurations have four major limitations listed below:
1. DPLLs are inherently unstable if said timing reference comprises components having frequencies higher than ⅕ of the DPLL bandwidth. Since time stamp messages are sent over regular communication links they are subjected to highly unpredictable time delay variations (TDVs) resulting from collisions between different packet streams sharing a common communication line. Such unpredictable TDVs are bound to introduce timing reference components having unknown frequency spectrums, when said timing reference is provided by exchanging time stamp packages sent over shared communication link. Resulting stability problems cause such conventional DPPL configurations to be highly unreliable in many applications.
2. Conventional digital phase detectors and said software algorithms minimizing phase errors, involve accumulation of phase digitization errors. Such accumulation causes an uncontrolled phase drift of the output clock, when a software error minimization procedure is unable to recognize and eliminate persistent existence of an digitization error corresponding to a lasting unknown frequency error of the output clock.
3. Conventional digital phase detectors; offer resolutions worse than that of phase steps limited by maximum clock frequency of IC technology, and they require complex processing for calculating precise phase skews when highly irregular edges of a reference timing are defined in newly emerging timing protocols such as IEEE 1588. Similarly clock synthesizers have phase steps resolutions bounded by maximum clock frequency of IC technology and furthermore they use frequency synthesis method unable to provide high precision control of phase transients of synthesized clock.
4. Conventional clock synchronization systems require expensive local oscillators, expensive external off-chip analog components, and expensive IC technologies suitable for mixed mode operations; in order to provide highly stable and low jitter synchronization clocks required in industrial control systems and in communication networks. Temperature stable crystal oscillators are major cost contributors exceeding ⅔ of total costs of synchronization systems. However in conventional solutions; low cost highly stable crystal cuts can not be used, since their oscillation frequencies are to low to be transformed into a stable low jitter clock.
Conventional synchronization systems use digital phase detectors which are >5 times less accurate than this inventions FPD, and frequency synthesizers producing uncontrolled phase transients during any frequency switching and introducing 10 times less accurate phase steps than this inventions phase synthesizer PS.
Such frequency synthesizers are based on direct digital frequency synthesis (DDFS) method modifying average frequency of an output clock by periodical removal of a clock pulse from a continues stream of pulses. Since said frequency synthesizers use over 10 times slower phase processing and introduce unknown numbers of 10 times less accurate phase steps than the PS, they are unable to perform any phase synthesis and produce uncontrolled phase transients during frequency switching and introduce much more jitter than the PS.
Consequently; in order to limit phase transients to acceptable levels, said conventional synchronization systems are bound to work in closed loop configurations wherein output clock phase is subtracted from reference clock phase and resulting phase error is minimized by a programmable control unit driving frequency synthesizer producing said output clock
3. Background Art of Receiver Synchronization Techniques
Insufficient accuracy of conventional synchronization for OFDM receivers impose major limitations on OFDM communication quality (see Cit. [1] and [2] listed below) and such limitations are compounded by rapidly growing data rates.
Some conventional solutions add specific preambles inserted into composite signal (Cit. [3], [4], [5], and [6]). Such preamble comprises similar parts having known phase (displacement in time) within the preamble.
Such preambles enable detection of symbol boundary time offset, by steps of:
evaluating correlation functions between OFDM signal portions shifted properly in time until such similar preamble parts are detected; using a phase of local clock frame marked by the similar parts detection and said known phase of such similar parts detected, for estimating time offset of the local frame; estimating frequency offset of the local clock versus transmitter clock by analyzing said correlation functions between such preamble parts shifted properly in time.
Other synchronization solutions analyze correlation estimates of received pilot preambles or pilot tones with predefined pilot preambles or pilot tones (Cit.[7]), in order to estimate time offset and frequency offset of the local clock frame.
However such use of preambles or pilots; reduces system efficiency by using signal power that could otherwise have been used for transmitting data, and allows limited accuracy only due to such detection and estimates sensitivity to channel interference and insufficient data supplied in the preamble.
There are also pilot-less synchronization techniques. One such pilot-less technique, named maximum likelihood (ML) method (Cit.[8]), utilizes inherent redundancy in OFDM signal, by correlating parts of the signal with other parts having known positioning within frame (cyclic prefix). However; as such pilot-less technique uses statistical methods and depend on transmitted data patterns, they are even less accurate than those using preambles or pilots.
Another pilot-less technique calculates timing offset and frequency offset from displacements of tone phases caused by said timing and frequency offsets (Cit. [9]).
Fundamental deficiency of conventional solutions characterized above is their inability to perform any accurate measurement of frequency offset; due to their reliance on using phase offset observed over single preamble/pilot period only for the frequency offset estimation. Such estimates degraded by unpredictable OFDM channel interference, can not be helped enough by averaging them for as long as each estimate is calculated over single preamble/pilot.
Still other significant deficiency of conventional synchronization is instability of their phase locked loops (used for phase and frequency tracking), caused by changing data patterns and/or unpredictable phase error components introduced into OFDM channel by generally unknown interference.
Such conventional synchronization solutions for OFDM receivers did not succeed in providing reliable and accurate recovery of a referencing frame providing time domain definition of phase and frequency of received OFDM composite frame. However such referencing frame defined in time domain, is essential for achieving accurate control of local oscillator frequency offset and receiver time offset (receiver phase error).
OFDM composite signal has not been originally designed to carry distinctive edges enabling detection of composite frame boundaries, and conventional DFT/IDFT frequency domain processing is not well suited for any accurate detection of such boundaries occurring in time domain either.
Conventional DSP techniques and processors used are not equipped to perform real-time processing of OFDM signal needed to produce such referencing frame maintaining predictable accurate timing relation to the OFDM signal received.
Such major deficiencies of conventional solutions are eliminated by the RST as it is explained in Subsection 2 of BRIEF SUMMARY OF THE INVENTION.
CITATIONS
[1] “Equalization for DMT-Based Broadband Modems” by Thierry Pollet at al., IEEE Communications Magazine, Volume 38, Issue 5, May 2000.
[2] “Retraining WLAN Receivers for OFDM Operation” by Ivan Greenberg, CommsDesign, January 2002.
[3] “A Symbol Synchronization Algorithm for OFDM Systems” by T. Salim at al., Communication Systems and Networks ˜AsiaCSN 2007˜April 2007
[4] “Synchronization Approach for OFDM based Fixed Broadband Wireless Access Systems” by M. Gertou, G. Karachalios, D. Triantis, K. Papantoni and P. I. Dallas, INTRACOM S. A., July 2005.
[5] “A Novel Scheme for Symbol Timing in OFDM WLAN Systems” by Yong Wang at al., ECTI Transactions on Electrical Eng. Electronics and Communications, August 2005.
[6] “Performance of a novel carrier frequency offset estimation algorithm for OFDM-based WLANs” by ZHAO Zhong-wei, Journal of Zhejiang University SCIENCE A, 2006 7(3).
[7] “Synchronization Schemes for Packet OFDM System” by Haiyun Tang, Kam Y. Lau and Robert W. Brodersen, IEEE International Conference on Communications, May 2003.
[8] “ML Estimation of Timing and Frequency Offset in Multicarrier Systems” by Jan-Jaap van de Beek, Magnus Sandell, Per Ola Borjesson, Lulea University of Technology, April 1996.
[9} “A Robust Timing and Frequency Offset Estimation Scheme for Orthogonal Frequency Division Multiplexing (OFDM) Systems” by Bruce McNair, Leonard J. Cimini, Nelson Sollenberger, VTC99 May 1999.
BRIEF SUMMARY OF THE INVENTION
1. Brief Summary of SCCS
Since the SCCS system is using said very accurate FPD and said very accurate PS free of any uncontrolled phase transients, it can implement an inherently stable open loop configuration wherein a programmable control unit (PCU) provides signals producing totally predictable output clock phase implementing precisely defined phase transfer function between an external timing reference and the output clock. In addition to elimination of said feedback related instability problems, such SCCS system allows ˜10 times better control of output clock phase transients and much lower phase jitter by synthesizing output phase with ˜10 times smaller and more accurate phase steps than conventional solutions.
The SCCS eliminates all four limitations mentioned in the “Background art” section, by contributing improvements listed below:
1. Since the SCCS uses an open-ended phase control system without any closed loop feedback, the SCCS enables inherently stable synthesis of the output clock, independently of reference frequency spectrum. 2. The SCCS defines digital frame phase detector (FPD), which eliminates said accumulation of digitization errors during phase tracking of highly irregular waveforms communicated with stamp messages of IEEE 1588 protocol. 3. The FPD part of the SCCS offers >5 times more accurate measurements of time errors, between the local clock and an external clock, occurring during variable lengths time intervals communicated by the external source. The SCCS defines digital phase synthesizer (PS) enabling direct precise control of phase transfer function between PSs input and output clocks, and the PS allows ˜10 times lower jitter of output clock phase. 4. The SCCS significantly reduces system manufacturing costs, by enabling use of inexpensive lower frequency oscillators including all oscillators already used by potential customers, and by enabling use of inexpensive standard CMOS technologies for synthesizing high precision synchronization clocks. The SCCS includes a Hybrid PLL (HPLL) which can multiply crystal frequencies as low as 30 kHz into a stable low jitter clock in GHz frequency range. The HPLL comprises a DPLL driving an analog PLL (APLL) using an analog phase detector (APD) with return input connected to an APLL output clock and with reference input connected to said PS receiving the APLL output clock. The DPLL minimizes digital phase error between said crystal oscillator clock and the APLL output clock, by introducing phase steps into a transfer function of said PS which produce appropriate phase errors on an output of said APD. Since the DPLL is programmable; it can convert any oscillator frequency into any local clock frequency, and consequently it allows use of local oscillator of any frequency including low frequency crystals and oscillators proven already in customers products.
Such HPLL solution is unique, as it allows: multiplication of said very low frequency clocks by factors which can be made as high as 50 000 without increasing jitter or causing stability problems, combined with indefinite flexibility and precision in setting frequency of generated high frequency clocks.
This major contributions over conventional solutions make the HPLL conclusively superior alternative to conventional PLLs in many major areas including analog, mixed mode SOC, signal processing, and all frequency control products where low jitter high multiplication is the major bottleneck.
In addition to the above mentioned advantages over conventional solutions; the SCCS offers unique ability of precise recovering of every single edge of incoming noisy wave-form, with adaptive time-domain noise filtering edge detector (NFED). The NFED densely over-samples incoming wave-form, and filters out phase noise from wave-form edges and eliminates amplitude glitches from wave-form pulses.
Still other advantage of SCCS is its ability to provide a single SOC design accepting all practically possible frequencies of timing references, as it is presented by a Heterodyne Timing Configuration of SCCS shown in FIG. 3 described in the next section.
In contrary to conventional solutions, the SCCS is not limited to discrete sets of input/output frequencies or local oscillator frequencies, but accepts a local oscillator (LocOsc) of any frequency and accepts an external reference clock (Ext_RefClk) of any frequency or an external reference waveform (Ext_RefWfm) carrying any reference frequency, while providing any required frequency of an SCCS output clock (OutClk).
Such very wide universality will allow synchronization products suppliers to replace wide variety of their SOC products with a single chip solution. Consequently, their own costs will be significantly reduced and such single chip solution will make their product much more competitive as being easier to use across diversified product lines produced by major equipment manufacturers who are their major clients.
The next section SUMMARY OF THE INVENTION; explains major configurations of the SCCS (see also FIG. 1 , FIG. 2 and FIG. 3 ), and justifying said configurations novel components such as the phase synthesizer, the frame phase detector and the noise filtering edge detector.
2. Brief Summary of Receiver Synchronization Techniques
The RST alleviates said deficiencies of conventional solutions, since the RST comprises:
supplementing or replacement of said conventional DSP techniques and processors unequipped to perform real-time processing of OFDM signal, with real-time synchronous processing techniques enabling very accurate detection of composite frame boundaries enabling time domain definition of said referencing frame maintaining predictable accurate timing relation to the OFDM signal received; recovery of timing of composite frames boundaries, and using such timing to define said referencing frame; using such referencing frame interval corresponding to any required plurality of OFDM symbols for estimating frequency offset, wherein estimation accuracy by one order higher than that of conventional solutions can be achieved (such accuracy improves proportionally to a length of referencing frame interval); inherently stable frequency locked phase synthesis method (FLPS) for receiver frequency and phase control, wherein such highly accurate frequency offset estimates are used by a frequency locked loop for controlling frequency of its oscillator clock while time offset (phase error) estimates are applied only to a phase synthesizer utilizing such oscillator clock for synthesizing local symbol frame phase minimizing such time offset estimates (i. e. phase aligned with the composite signal frame).
The RST comprises methods and systems for accurate and reliable recovery of said referencing frame from preambles or pilots commonly used already in OFDM systems, thus enabling substantially better receiver synchronization to OFDM composite signal frame.
Furthermore the RST comprises solutions enabling very accurate recovery of the referencing frame from data carrying tones only, and thus RST contributions over conventional solutions include; 10× lower frequency and time offset combined with improvement of system efficiency by eliminating preambles and pilots needed previously.
SUMMARY OF THE INVENTION
1. Open Ended Configuration of Software Controlled Clock Synthesizer
The open ended configuration of SCCS (OEC) is presented in FIG. 1 . Such configuration comprises two major parts described below.
The first part is said Hybrid PLL (HPLL) for multiplying said local oscillator frequency provided by a crystal producing frequencies as low 30 kHz, by a programmed by PCU factor which can exceed 50 000 without any increase of jitter levels and without any stability problems. The HPLL provides practically indefinite flexibility and precision in setting frequency of generated high frequency clocks. Resulting frequency can rise as far as is it supported by a voltage controlled crystal oscillator (VCXO), as long as it remains lower than maximum clock frequency which exceeds GHz ranges in present IC technologies.
The HPLL comprises a DPLL (DPLL) driving an analog PLL (APLL) using an analog phase detector (APD) with return input connected to an APLL output clock (LocClk) and with reference input connected to a local phase synthesizer (LOC_PS) receiving the APLL output clock. The DPLL minimizes digital phase error 2 (PhaErr2) between said local oscillator (LocOsc) and the LocClk, by introducing phase steps into an output phase of said LOC_PS which are converted by the APD into analog phase errors controlling phase locking between the LocClk and the OscClk. The DPLL uses a frame phase detector 2 (FPD2) for measuring said PhaErr2 which is read by a programmable control unit (PCU) using it for producing said phase steps introduced into said LOC_PS output phase, wherein amount of introduced phase steps is controlled using an MC=1_INT signal received by the PCU from the LOC_PS. The MC=1_INT signals a request from the LOC_PS demanding the PCU to send the next series of said phase steps when the last series is applied already. The FPD2 receives PCU control signals programming expected relation between phase of the OutClk and phase of a sampling clock (SampClk) derived from the LocClk through a simple multiplication by a factor <8.
The second part is an open ended software controlled synthesizer (OE_SCS) using PCU software sub-routines for providing a programmable phase transfer function (PTF) between the Ext_RefWfm and the OutClk.
The OE_SCS offers; unique ability to program very precisely synchronized phase free of any uncontrolled transients. Therefore, the OE_SCS provides ˜10 times better precision in frequency and phase control than conventional solutions. Furthermore, the OE_SCS offers inherently stable configuration independently of said highly unpredictable frequency spectrum of the time delay variations occurring in the Ext_RefWfm. Consequently, the OE_SCS eliminates serious stability problems of conventional clock synchronizers bound to use closed loop configurations for implementing message-based protocols.
Said PCU controls operations of the OUT_PS by defining series of phase steps inserted by the OUT_PS into a phase of the OUTCLK.
The PCU calculates said phase steps by processing:
a phase error 1 (PhaErr1) received form a frame phase detector 1 (FPD1) measuring phase error between the sampling clock and a filtered reference wave-form (Filt_RefWfm);
time stamp messages received from a Time Stamp Decoder (TSD) recovering such messages from the FILT_RefWfm produced by a noise filtering edge detector (NFED).
The PCU supplies the next series of said phase steps in response to the interrupt MC=1_INT from the OUT_PS which signals that insertions of the last series has been completed.
Furthermore the PCU controls operations of the NFED providing adaptive time domain filtering of the Ext_RefWfm carrying synchronization signals which can be encoded into time stamp messages or can be conventional BITS references.
The PCU receives unfiltered wave-form samples from the NFED and calculates most suitable noise filtering masks and algorithms which the PCU communicates back to the NFED (see Subsection 8. Noise Filtering Edge Detector).
Compared to a moment when a sync message requesting capturing of a time stamp is received by the PCU; an exact sync edge of the FILT_RefWfm destined to capture said time stamp can be displaced in time by a known number of message symbols (edge displacement). Such edge displacement is determined by a messaging protocol used.
Since FPD1 keeps capturing time stamps of all received edges of the FILT_RefWfm, the FPD1 or the PCU shall be equipped with an edge selection circuit (ESC). The ESC provides selection of time stamps captured by said sync edge and is synchronized by the time stamp messages produced by the Time Stamp Decoder.
Further definitions of a synchronization means provided by the OEC, such as Free-Run and Hold-Over modes, are provided in the Subsection 4.
2. Open Ended Configuration of SCCS with External Synchronization Mode
The open-ended configuration of SCCS with external synchronization mode (OEC_ESM) is presented in FIG. 2 and is described below.
The OEC_ESM comprises the previously explained OEC and is further extended by adding an output clock analog PLL (OutClk_APLL). The OutClk_APLL filters out jitter from a synthesized clock from the OUT_PS (SynOutClk) and produces SCCS output clocks (OutClk(T:1)) which are phase aligned with a reference clock selected by the PCU from a set of timing references including the SynOutClk, external reference clocks (Ext_RefClk) and a clock signal form a mate SCCS unit (f_mate).
Said external reference clocks are used in the external synchronization mode, wherein they are produced by a master synchronization unit and are used to synchronize multiple other units located in a back-plane of a network element. However said other units can alternatively use other synchronization references available in other synchronization modes and may be synchronized by the Ext_RefWfm carrying a message based protocol or BITS clocks.
Such plurality of synchronization references and modes allows switching to one of alternative references when an active reference fails.
The f-mate clock from a mate unit allows Master/Slave protection switching which is described in the Subsection 4.
The output clock analog PLL comprises:
a reference selector (RFS) connected to the SynOutClk from the OUT_PS and to the external reference clocks and to the f_mate clock and to the PCU, wherein the PCU controls selections of made by the RFS producing a reference clock (RefClk) for the OutClk_APLL;
a return clock divider (RCD) connected to a filtered output clock (Fil_OutClk) of the OutClk_APLL and to the PCU, wherein the PCU defines a division coefficient matching frequency of a return clock (RetClk) for the OutClk_APLL with a frequency of the RefClk;
an analog phase detector OutClk APD connected to the reference clock and to the return clock, and producing an analog phase error (PhaDet_UP/DN) driving an output clock loop filter (OutLoopFil) which drives a VCXO producing the filtered output clock;
an output PLL (OUT_PLL) for multiplying one selected OutClk(T:1) clock and for providing phase alignment between all the OutClk_APLL and the Fil_OutClk, wherein the OUT_PLL is connected to the selected OutClk(T:1) clock and to the Fil_OutClk;
an output clocks generator (OCG) connected to the output of the OUT_PLL and to the PCU, wherein the OCG produces the OutClk(T:1) which are phase aligned but have different frequencies wherein the PCU controls OCG operations by programming said frequencies of the SCCS output clocks.
Further definitions of synchronization means provided by the OEC_ESM, are provided in the Subsections 3 and 4.
3. Heterodyne Timing Configuration of SCCS
The heterodyne timing configuration (HTC) simplifies SCCS by integrating:
both the APLL and the OC APLL from the OEC_ESM, into a single APPL;
and both the REF PS and OUT_PS from the OEC_ESM, into a single RET_PS.
The two previous configurations of SCCS offer said practically unlimited universality in accepting said local oscillator (LocOsc) of any frequency and accepting said external reference waveform (Ext_RefWfm) carrying any reference frequency, while providing all practically needed frequencies of said SCCS output clocks (OutClk(T:1)).
The HTC extends this universality even further by enabling acceptance of practically unlimited ranges of said external reference clocks (Ext_RefClk) as well.
Therefore despite implementing a close loop system, the HTC may still be used as a less costly alternative; if timing reference is not provided by a message based protocol, or if a message-based protocol is used in simple networks with stable TDVs.
Said integration is achieved by placing a return phase synthesizer (RET_PS) into a return path of the integrated APLL. Consequently said phase steps supplied by the PCU need to be reversed as they are subtracted from a phase of a reference clock of the APLL instead of being added to it. Indefinite RET_PS flexibility in phase and frequency generation makes it much better frequency divider than the previous configuration Return Clock Divider and allows said unlimited flexibility in accepting all frequencies of the Ext_RefClk.
Resulting HTC comprises:
a programmable control unit (PCU) for implementing a programmable phase transfer function (PTF) between the OutClk and the Ext_RefClk or the Ext_RefWfm, wherein the PCU controls operations of the return phase synthesizer (RET_PS), the PCU has a terminals for an interrupt MC=1_INT and for a first phase error (PhaErr1) and for a second phase error (PhaErr1) and for a time stamp message and for a waveform sample; the reference selector (RFS) connected to a filtered local clock (Fil_OutClk) and to the external reference clocks (Ext_RefClk) and to the f_mate clock and to the PCU, wherein the PCU defines selections made by the RFS producing a reference clock (RefClk) for the analog phase detector (APD); the RET_PS connected to a filtered output clock (Fil_OutClk) and connected to the PCU wherein the RET_PS requests PCU to supply the next series of phase steps by activating the MC=1_INT, wherein the RET_PS introduces such phase steps into the Fil_OutClk thus synthesizing a return clock (RetClk) for the APD; the APD connected to the RefClk and to the RetClk, the APD producing an analog phase error (PhaDet_UP/DN) driving an output clock loop filter (OutLoopFil) which drives a VCXO producing the filtered output clock; the output PLL (OUT_PLL) for multiplying one selected OutClk(T:1) clock and for providing phase alignment between all the OutClk_APLL and the Fil_OutClk wherein the OUT_PLL is connected to the selected OutClk(T:1) clock and to the Fil_OutClk, wherein the OUT_PLL produces an output reference clock (OutRef) connected to the OCG and to the FPD2; the output clocks generator (OCG) connected to the output of the OUT_PLL and to the PCU, wherein the OCG produces the OutClk(T:1) which are phase aligned but have different frequencies wherein the PCU controls OCG operations by programming said frequencies of the SCCS output clocks; the NFED and the TSD and the FPD1 and the FPD2 having the same connectivity and performing the same operations as defined in the Subsection 1, with the exception of the FPD2 which is connected to the OutRef and to the LocOsc and to the PCU; wherein the PCU uses its internal micro-operations for implementing filter functions of an on chip digital PLL (DPLL) by processing the PhaErr1 and the PhaErr2 and the time stamp messages into the PCU output driving the RET_PS into producing the synthesized return clock providing compliance of the SCCS output clocks with the phase transfer function defined by the PTF, wherein the PCU controls NFED operations as it is described in the Subsection 1.
4. SCCS Configurations
In contrary to conventional frequency synthesizers, SCCS phase synthesizer produces totally predictable phase and frequency responses to received from the PCU control signals. Therefore it enables said open ended configurations which can work with only one frame phase detector (FPD) for measuring phase errors between a timing reference and a local clock, in order to implement an actual synchronization system. The second FPD in the open ended configuration explained in the Subsection 1, is used for the frequency multiplication of said local oscillator only. If a local clock had sufficiently high frequency, the FPD would not be needed at all. As said conventional frequency synthesizers produce unpredictable transient during frequency switching, they require second digital phase detector for providing feedback about a phase of synthesizers output clock in order to reduce said phase transients with a DPLL.
An open ended configuration without said multiplication of LocOsc frequency is defined below. A Software Controlled Clock Synthesizer (SCCS) for implementing a programmable phase transfer function (PTF) between an SCCS output clock (OutClk) and external reference clocks (Ext_RefClk) or an external reference carrying wave-form (Ext_RefWfm) such as BITS references or line references or time stamp messages; the SCCS comprises:
a programmable control unit (PCU) using software subroutines for controlling SCCS status and for said implementation of the PTF, wherein the PCU controls operations of a return clock phase synthesizer (RET_PS), the PCU has terminals for interrupts from other SCCS circuits and for a first phase error (PhaErr1) and for a second phase error (PhaErr2) and for a time stamp message and a for a waveform sample; the RET_PS for synthesizing a return clock (RetClk), the RET_PS connected to the PCU and to the SCCS output clock (OutClk); the APLL for producing the OutClk, wherein a reference input of the APLL is connected to the OutClk or to the Ext_RefClk while the return input of the APLL is connected to the synthesized RetClk; a first frame phase detector (FPD1) receiving a local reference clock (LocClk) and the Ext_RefWfm or receiving the LocClk and the OutClk or receiving the Ext_RefClk and the OutClk, wherein the FPD1 produces the PhaErr1 connected back to the PCU; wherein said PCU uses said software subroutines for implementing a digital PLL (DPLL) by processing said first phase error and the second phase error into the PCU output driving the RET_PS into synthesizing the RetClk providing compliance of the APLL output clock with the phase transfer function defined by the PTF.
The SCCS includes reference selection means for alternative use of one of multiple connected external timing references, such as reference clocks or external waveforms, for producing the SCCS output clock, the SCCS further comprises:
a reference selector connected to multiple external timing references and controlled by the PCU, wherein the PCU selects one of the multiple timing references for being connected to the FPD1 which is read by the PCU and used by PCU subroutines for controlling the SCCS output clock; activity monitors for the external timing references for producing status signals indicating active/non-active conditions, wherein said status signals are connected to the PCU; wherein the output signals of the activity monitors are read and processed by the microprocessor which is producing reference selection signals connected to the reference selectors.
The SCCS further comprises:
an output phase locked loop (OUT-PLL) referenced by the APLL output clock and producing a fundamental output clock, wherein the OUT-PLL has a return input connected to one SCCS output clock; an output clock generator (OCG) connected to the fundamental output clock, the OCG produces a plurality of the SCCS output clocks (OutClk).
The SCCS further comprises:
interface circuits, for communication with an external control processor, connected to the external control processor and to the PCU (see the Parallel Interface and the Serial Interface in the FIG. 1 and FIG. 2 and FIG. 3 ); wherein the interface circuits and the PCU enable the external control processor to read information about statuses of the activity monitors and to select an external reference clock or the local reference clock for referencing the SCCS output clock.
Furthermore in the interface circuits and the PCU enable the external control processor to perform switching of mode of operation of the SCCS between the APLL mode and the DPLL mode.
The SCCS PCU is provisioned to perform operations listed below:
reading information about statuses of the activity monitors and selecting an external timing reference or the local reference clock for referencing the SCCS output clock; switching mode of operation of the SCCS between the APLL mode and the DPLL mode.
Furthermore the SCCS is provisioned to perform a master/slave mode switching for maintaining phase alignment between an active SCCS unit and a backup SCCS unit installed in a back-plane for protection switching, the SCCS comprises:
a master/slave subroutine reading activity monitor of a reference clock provided by a mate SCCS unit and reading internal status of the own SCCS unit; wherein the master/slave subroutine performs switching to the master mode by selecting other reference clock than the mate's reference clock when the mate's reference clock becomes inactive or performs switching to the slave mode by selecting the mate's reference clock when the mate's reference clock is detected active during a power-up initialization of the own SCCS unit.
The SCCS comprises using a programmable phase synthesizer to produce an Analog PLL return clock, which can be reprogrammed to match a frequency of a reference clock of said Analog PLL. Furthermore the SCCS comprises:
applying an output clock of the APLL to a reference input of the APLL;
using the return clock synthesizer for inserting phase deviations between the APLL return clock and the output clock applied to the APLL reference input;
using the inserted phase deviations for implementing required phase and frequency transfer functions between the APLL output clock and other SCCS reference clocks;
implementing digital PLL (DPLL) algorithms for providing the required phase and frequency transfer functions.
Still furthermore the SCCS comprises:
using frame phase detectors (FPDs) for measuring phase errors between the APLL output clock and said other SCCS reference clocks;
using the PCU for processing the measured phase errors and producing control codes for the return clock synthesizer, which implement pre-programmed phase and frequency transfer functions between the APLL output clock and said other SCCS reference clocks.
The SCCS comprises:
Said analog phase locked loop (APLL) for producing the output clock (OutClk) which can be locked to the external reference clock (Ext_RefClk), unless the APLL is driven by the digital phase locked loop (DPLL);
Said DPLL can provide locking to the Ext_RefWfm (which can be a GPS clock)., or to a local oscillator.
The SCCS further comprises:
programmable frequency dividers for a reference signal and for return signal of said APLL, for providing programmable bandwidth adjustments of the APLL;
programmable frequency dividers in the output clock generator (OCG) which can be reprogrammed by the PCU, in order to allow utilizing a single pin of the OutClk(T:1) for providing multiple different output clock frequencies;
activity monitoring circuits for synchronizer input clocks and output clocks;
frequency monitoring circuits for synchronizer reference clocks;
status control circuits for switching synchronizer modes of operation and active reference clocks, based on an analysis of said activity and frequency monitoring circuits;
phase transfer control circuits for providing a required phase transfer function between an active reference clock and synchronizer output clocks;
a serial interface which allows the status control circuits and the phase transfer control circuits to be monitored and reprogrammed by an external controller (see the Serial Interface in the FIG. 1 , FIG. 2 and FIG. 3 );
a parallel interface which allows the status control circuits and the phase transfer control circuits to be monitored and reprogrammed by an external controller controller (see the Prallel Interface in the FIG. 1 , FIG. 2 and FIG. 3 );
automatic reference switching functions including hold-over and free-run switching, which are performed by the status control circuits and are based on monitoring a status of the activity and frequency monitoring circuits;
a master/slave switching circuit which allows a pair of integrated synchronizers to work in a master/slave configuration having a slave synchronizer being phase locked to a mate clock which is generated by a mate master synchronizer;
The above listed status control circuits and phase transfer control circuits can be implemented as separate on-chip control units or with a single on-chip PCU.
APLL mode of operation in the Heterodyne Timing Configuration is described below.
One of the external reference clocks (Ext_RefClk) is selected to be applied to the APLL reference input and the return phase synthesizer (RET_PS) is switched by the PCU into producing the APLL return clock which is matching said selected external reference clock.
The implementation of a DPLL mode is explained below.
The APLL output clock Fil_OutClk is applied to the APLL reference input and the return phase synthesizer (RET_PS) is switched by the PCU into producing the APLL return clock which is matching said output clock Fil_OutClk.
The FPD1 measures a phase error between the output clock multiplication SampClk and the Ext_RefWfm, and the FPD2 measures a phase error between the SampClk and the local oscillator LocOsc.
The PCU reads the above phase errors and uses them to calculate new contents of the RET_PS's periodical adjustment buffers and the fractional adjustment buffers needed for inserting phase deviations required for providing a phase transfer function (PTF), between the output clock Fil_OutClk and the Ext_RefWfm, which is already preprogrammed in the PCU.
The invention includes providing slave mode implementation which replaces the external reference clock with the mate SCCS output clock f_mate, in order to drive the above described APLL configuration. The slave mode allows maintaining phase alignment between active and reserve SCCS units, for the purpose of avoiding phase hits when protection switching reverts to using clocks from the reserve SCCS unit.
The invention includes using the above mentioned method of slave SCCS phase alignment for all 3 configurations shown in the FIG. 1 , FIG. 2 and FIG. 3 ).
5. Digital Wave Synthesis from Multi Sub-Clocks
The invention comprises the digital wave synthesis from multi-sub-clocks (DWS MSC) as a new timing method and circuit for programming and selecting a phase and a frequency of a synthesized clock.
The DWS MSC comprises programmable phase modifications which are defined below:
Phase increases of the synthesized clock are provided; by adding whole clock periods and/or fractional sub-clock delays, obtained from serially connected delay elements which the reference clock is propagated through, to a present phase obtained from a counter of reference clock periods and/or a present fractional sub-clock delay.
Phase decreases of the synthesized clock are provided; by subtracting whole clock periods and/or fractional sub-clock delays, obtained from serially connected delay elements which the reference clock is propagated through, from a present phase obtained from a counter of clock periods and/or a present fractional sub-clock delay.
The DWS MSC provides ˜10 times better phase adjustment resolution than the commonly used DDFS method; because the DWS MSC can modify phase with time intervals specified in fractions of clock cycle, instead of inserting or eliminating whole clock cycles from a synthesized clock. Therefore, the phase hits and resulting jitter are reduced by around 10 times compared to the DDFS method.
The DWS MSC provides an implementation of programmable algorithms for synthesizing a very wide range of low and high frequency wave-forms.
The DWS MSC comprises; a 1-P phase generator, a synchronous sequential phase processor (SSPP) for real time processing and selection of a phase of out-coming wave-form, and a programmable computing unit (PCU) for controlling SSPP operations and supporting signal synthesis algorithms.
Said 1-P phase generator is an extension of a 1bit odd/even phase generator to p bits enabling 2 p =P phases to be generated from every reference sub-clock, as it is defined below.
The odd/even phase generator provides splitting of reference sub-clocks, generated by outputs of a reference propagation circuit built with serially connected gates which a reference clock is propagated through, into odd phase sub-clocks which begin during odd cycles of the reference clock and even phase sub-clocks which begin during odd cycles of the reference clock, wherein the odd/even phase selector comprises:
said reference propagation circuit connected to the reference clock; serially connected flip-flops, wherein a clock input of a first flip-flop is connected to the reference clock and a data input of a first flip-flop is connected to an inverted output of the first flip-flop while a clock input of any other Nth flip-flop is connected to an (N−1) output of the reference propagation circuit and a data input of the N flip-flop is connected to an output of the (N−1) flip-flop; connected to the serially connected flip-flops an odd/even selector generating the odd sub-clocks which begin during every odd reference clock cycle and the even sub-clocks which begin during every even reference clock cycle, wherein the output of the 1 st flip-flop is used to select odd and even reference clocks while the output of the Nth flip-flop is used to select odd and even reference sub-clocks from the (N−1) output of the reference propagation circuit.
The odd/even phase generator is extended into the 1-P phase generator splitting the reference sub-clocks into 1-P phase sub-clocks which begin during the corresponding 1-P cycles of the reference clock, wherein the 1-P phase selector further comprises:
a parallel 1-P sub-clock counter built as an extension to the first flip-flop working as 1-2 counter wherein the whole 1-P sub-clock counter is clocked by the first reference sub-clock, wherein an output of the 1-P sub-clock counter represents a 1-P phase number of the first sub-clock; 2-N parallel multi-bit buffers built as extensions to the original 2-N flip-flops working as 1 bit buffers wherein the whole 1-P sub-clock counter is clocked by the 2 nd reference sub-clock into the first multi-bit buffer which is clocked by the 3 rd reference sub-clock into the 2 nd multi-bit buffer and the content of the 1-P counter is similarly propagated into all next buffers until the Nth sub-clock loads the N−2 buffer into the N−1 buffer, wherein the 1 st buffer defines a phase number minus 1 for the 2 nd reference sub-clock and next buffers define similarly phase numbers for their corresponding reference sub-clocks until the N−1 buffer defines a phase number minus (N−1) for the Nth reference sub-clock. 1-P phase selectors built as extensions to the corresponding odd/even selectors wherein a first 1-P selector is connected to the 1-P sub-clock counter and selects a phase, of the first reference sub-clock, defined by the 1-P sub-clock counter while every next N−K+1 phase selector is connected to its N−K buffer and to its N−K+1 reference sub-clock (0<K<N), wherein every next N−K+1 phase selector generates phases, of its N−K+1 sub-clock, defined by its buffer content plus (N−K).
The 1-P phase generator can use both solutions defined below:
using rising edges of the reference sub-clocks for clocking the 1-P sub-clock counter and the 2-P buffers while negative pulses of the reference sub-clocks are used for activating outputs of the 1-P selectors generating the 1-P phase sub-clocks;
or using rising edges of the reference sub-clocks for clocking the 1-P sub-clock counter and the 2-P buffers while negative pulses of the reference sub-clocks are used for activating outputs of the 1-P selectors generating the 1-P phase sub-clocks.
Furthermore the 1-P phase generator can use the serially connected gates of the reference propagation circuit, which are connected into a ring oscillator controlled by a PLL circuit or are connected into a delay line control by a delay locked loop (DLL) circuit or are connected into an open ended delay line.
Furthermore this 1-P phase generator includes extending the remaining 2-N flip-flops with parallel sub-clock counters, the same as the parallel sub-clock counter extending the 1st flip-flop, instead of using the defined above 2-P multi-bit buffers. The use of the 2-P parallel counters requires adding preset means for all the 1-P counters, in order to maintain the same or predictably shifted content in all the 1-N parallel counters. Continues maintaining of said predictability of all the parallel counters content is necessary for generating predictable sequences of multiphase sub-clocks.
Said SSPP comprises a selection of one of multi sub-clocks for providing an edge of out-coming synthesized signal, where said sub-clocks are generated by the outputs of serially connected gates which an SSPP reference clock is propagated through.
The SSPP comprises calculating a binary positioning of a next edge of the out-coming wave-form versus a previous wave edge, which represents a number of reference clock cycles combined with a number of reference clock fractional delays which correspond to a particular sub-clock phase delay versus the reference clock.
Furthermore the SSPP comprises selective enabling of a particular sub-clock, which provides the calculated phase step between the previous and the current wave-form edges.
The SSPP further comprises a synchronous sequential processing (SSP) of incoming signal by using multiple serially connected processing stages with every stage being fed by data from the previous stage which are clocked-in by a clock which is synchronous with the reference clock. Since every consecutive stage is driven by a clock which is synchronous to the same reference clock, all the stages are driven by clocks which are mutually synchronous but may have some constant phase displacements versus each other.
The synchronous sequential processor (SSP) multiplies processing speed by splitting complex signal processing operation into a sequence of singular micro-cycles, wherein:
every consecutive micro-cycle of the complex operation is performed by a separate logical or arithmetical processing stage during a corresponding consecutive time slot synchronous with a reference clock providing a fundamental timing for a synthesized wave-form; serially connected sequential stages are connected to a programmable control unit (PCU), wherein the sequential stages are clocked by reference sub-clocks generated by a reference propagation circuit built with serially connected gates which the reference clock is propagated through; whereby inputs from the PCU are processed into a phase delay between a next edge of the synthesized wave-form versus a previous edge and a position of the next edge is calculated by adding the phase delay to a position of the previous edge, wherein the positions of wave-form edges are provided by a last of the sequential stages and said positions are expressed as numbers identifying reference sub-clocks needed for generating said wave-form edges.
The above defined SSP can be implemented by processing said inputs from the PCU into a phase modification step which is added to a period of the reference clock in order to calculate the phase delay.
Furthermore this invention includes the SSP circuit upgraded into a parallel multiphase processor (PMP) by extending the time slot allowed for the micro-cycles of the synchronous sequential processor by a factor of P, wherein:
2-P stages are added to the original sequential stage and every one of the resulting 1-P parallel multiphase stages is clocked with a corresponding 1-P phase sub-clock, wherein such 1-P phase sub-clock begins during the corresponding to that phase 1-P cycle of the reference clock and has a cycle which is P times longer than the reference clock cycle; whereby consecutive 1-P parallel multiphase stages have processing cycles overlapping by 1 cycle of the reference clock wherein every 1-P parallel processing stage has P times longer cycle time equal to the cycle time of the corresponding 1-P phase sub-clock used for timing that stage.
The parallel multiphase processor further comprises:
a parallel processing phase 2-P built with plurality of 2-P parallel multiphase stages which are connected serially and are driven by the phase sub-clocks belonging to the same 2-P phase.
The SSPP invention comprises the use of the parallel multiphase processing for synthesizing a target wave-form by assigning consecutive parallel phases for the processing of a synthesized signal phase using signal modulation data provided by a programmable control unit (PCU) or by any other source.
Consequently the SSPP comprises using 1 to N parallel phases which are assigned for processing incoming signal data with clocks corresponding to-reference clock periods number 1 to N, as it is further described below:
circuits of phase1 process edge skews or phase skews or other incoming signal data with a clock which corresponds to the reference clock period number 1; circuits of phase2 process edge skews or phase skews or other incoming signal data with a clock which corresponds to the reference clock period number 2; finally circuits of phaseN process edge skews or phase skews or other incoming signal data with a clock which corresponds to the reference clock period number N.
Said parallel multiphase processing allows N times longer processing and/or sub-clocks selection times for said multiphase stages, compared with a single phase solution.
The above mentioned sub-clock selecting methods further include:
using falling edges of said sub-clocks for driving clock selectors which select parallel processing phases during which positive sub-clocks are enabled to perform said synthesized wave-form timing, or using rising edges of said sub-clocks for driving selectors which select parallel processing phases during which negative sub-clocks are enabled to perform said synthesized wave-form timing; using serially connected clock selectors for enabling consecutive sub-clocks during said processing phases, in order to assure that the enabled sub-clocks will occur within a selected processing phase and to enable selection of a sub-clock specified by a number contained in a fraction selection register of a particular processing phase.
The SSPP includes using said serially connected gates:
as being an open ended delay line; or being connected into a ring oscillator which can be controlled in a PLL configuration; or being connected into a delay line which can be controlled in a delay locked loop (DLL) configuration.
Every said sub-clock phase delay versus the reference clock phase amounts to a fraction of a reference clock period which is defined by a content of a fraction selection register which is assigned for a particular processing phase and is driven by the SSPP.
The SSPP includes a parallel stage processing of an incoming signal by providing multiple processing stages which are driven by the same clock which is applied simultaneously to inputs of output registers of all the parallel stages.
The SSPP further comprises:
a merging of processing phases which occurs if multiple parallel processing phases are merged into a smaller number of parallel phases or into a single processing phase, when passing from a one processing stage to a next processing stage; a splitting of processing phases which occurs if one processing phase is split into multiple processing phases or multiple processing stages are split into even more processing stages, when passing from a one processing stage to a next processing stage.
The SSPP includes using the 1-P phase generator defined above to generate SSPP clocks which drive said parallel phases and said sequential stages, and to generate selector switching signals for said merging and splitting of processing phases.
The SSPP includes time sharing of said parallel phases: which is based on assigning a task of processing of a next wave-form edge timing to a next available parallel processing phase.
The SSPP comprises a timing control (TC) circuit, which uses decoding of reference clock counters and/or other wave edge decoding and said SSPP clocks, for performing said time sharing phase assignments and for further control of operations of an already assigned phase.
The SSPP comprises passing outputs of a one parallel phase to a next parallel phase, in order to use said passed outputs for processing conducted by a following stage of the next parallel phase. The outputs passing is performed: by re-timing output register bits of the one phase by clocking them into an output register of the next parallel phase simultaneously with processing results of the next parallel phase.
The SSPP further comprises all the possible combinations of the above defined: parallel multiphase processing, parallel stage processing, synchronous sequential processing, merging of processing phases, splitting of processing phases, and outputs passing.
The SSPP includes processing stage configurations using selectors, arithmometers, and output registers, which are arranged as it is defined below:
input selectors select constant values or outputs of previous stages or outputs of parallel stages or an output of the same stage to provide arithmometer inputs, and arithmometer output is clocked-in to an output register by a clock which is synchronous to the reference clock; multiple arithmometers are fed with constant values or outputs of previous stages or outputs of parallel stages or an output of the same stage, and an output selector selects an arithmometer output to be clocked-in to an output register by a clock synchronous to the reference clock; the above defined configuration as being supplemented by using an output of an output selector of a parallel processing stage for controlling functions of other output selector.
The SSPP comprises:
using switching signals of said input selectors for producing pulses which clock data into output registers of previous stages;
using switching signals of said output selectors for producing pulses which clock data into output registers of previous stages;
The SSPP also comprises:
using results obtained in earlier stages for controlling later stages operations, and using results obtained in the later stages for controlling the earlier stages operations.
Proper arrangements of said parallel and sequential combinations and said stages configurations provide real time processing capabilities for very wide ranges of signal frequencies and enable a wide coverage of very diversified application areas.
The DWS MSC comprises two different methods for accommodating a phase skew between the reference clock and a required carrier clock frequency of the transmitted signal, and both methods allow elimination of ambiguities and errors in encoding of output signal data patterns. Said two methods are further defined below:
a source of the reference clock provides frequency or phase alignment with the timing of the data which are being encoded and sent out in the synthesized output wave-form; phase skews between the reference clock and the timing of the destined for transmission data are digitally measured and translated into implemented by the SSPP phase adjustments of the synthesized signal which provide required carrier frequency of the transmitted output signal; both above mentioned methods include measurements of phase or frequency deviations of the destined for transmission data versus the reference clock, and using said measurements results to assure required carrier frequency of the synthesized signal.
Furthermore the DWS MSC method comprises phase modulations of the synthesized wave-form by adding or subtracting a number of reference clock periods and/or a number of fractional delays to a phase of any edge of the synthesized wave-form.
Said adding or subtracting of a number of reference clock periods is further referred to as a periodical adjustment, and said adding or subtracting of fractional delays is further called a fractional adjustment.
The DWS MSC method allows synthesizing of any waveform by modulating a phase of the reference clock with periodical and/or fractional adjustments of any size.
6 Phase Synthesizer
The invention also includes the Phase Synthesizer (PS) for carrying out the DWS MSC method; as it is further explained below and is shown in FIG. 4 , FIG. 4A , FIG. 5 , and FIG. 6 . The Timing Diagram of the PS is shown in the FIG. 7 .
Said phase synthesizer provides programmable modifications of a phase of a synthesized clock by unlimited number of gate delays per a modification step with step resolution matching single gate delay at steps frequencies ranging from 0 to ½ of maximum clock frequency, wherein:
a delay control circuit is connected to a programmable control unit (PCU) wherein the delay control circuit defines size and frequency of phase delay modifications of the synthesized clock versus a reference clock, the delay control circuit also having a terminal connected to reference sub-clocks generated by a reference propagation circuit or connected to odd/even sub-clocks generated by an odd/even phase selector; the reference clock is connected to the reference propagation circuit consisting of serially connected gates wherein outputs of the gates generate the reference sub-clocks providing variety of phase delays versus the reference clock; the reference sub-clocks are connected to an odd/even phase selector which splits the reference sub-clocks by generating separate odd sub-clocks and even sub-clocks, wherein the odd sub-clocks begin during odd cycles of the reference clock and the even sub-clocks begin during even cycles of the reference clock; a clock selection register is loaded by the odd sub-clocks and by the even sub-clocks with the outputs of the delay control circuit, wherein the odd sub-clocks or the even sub-clocks beginning during an earlier cycle of the reference clock download outputs of the delay control circuit which select the even sub-clocks or the odd sub-clocks beginning during a later cycle of the reference clock for providing the synthesized clock; an output selector is connected to the output of the clock selection register and to the outputs of the odd/even phase selector, wherein the output selector uses inputs from the clock selection register for selecting output of the odd/even phase selector which is passed through the output selector for providing the synthesized clock.
The above defined PS can use the odd/even phase generator or the 1-P phase generator, which have been already defined above.
The PS can use the delay control circuit implemented with the parallel multiphase processor (PMP) which has been already defined above.
The PS comprises 2 different implementation methods, which are explained below.
The first PS implementation method is based on moving a synthesized clock selection point from a delay line which propagates a reference clock (see the FIG. 4 ); wherein:
said phase increases are provided by moving said selection point of the synthesized clock from the reference clock propagation circuit, in a way which adds gate delays to a present delay obtained from the propagation circuit;
said phase decreases are provided by moving said selection point of the synthesized clock from the reference clock propagation circuit, in a way which subtracts gate delays from a present delay obtained from the propagation circuit;
The first PS implementation method is conceptually presented in FIG. 4 & FIG. 6 , and its principles of operations are explained below.
The PLL×L Freq. Multiplier produces the series of sub-clocks Clk0, ClkR-Clk1.
The sub-clock Clk0 keeps clocking in a reversed output of its own selector PR0.
The sub-clocks CLkR-Clk1 keep clocking in outputs of the previous selectors PR0, PRR-PR2 into their own selectors PRR-PR1.
Since the selector PR0 is being reversed by every Clk0, every selector in the PR0, PRR-PR1 chain is being reversed as well by a falling edge of its own sub-clock Clk0, ClkR-Clk1, and every selector in the chain represents reversal of its predecessor which is delayed by a single sub-clock fractional delay.
Consequently the PR0, PR1N-PRR select sub-clocks Clk0, Clk1-ClkR during any odd processing phase, and their reversals PR0N, PR1-PRRN select sub-clocks Clk0, Clk1-ClkR during any even processing phase.
The odd/even processing phase has been named phase1/phase2, and their sub-clocks are named 1Clk0, 1Clk1-1ClkR/2Clk0, 2Clk1-2ClkR accordingly.
Since said phase1/phase2 sub-clocks are used to run a phase synthesis processing in separate designated for phase1/phase2 phase processing stages which work in parallel, a time available for performing single stage operations is doubled (see also the FIG. 6 for more comprehensive presentation of said parallel processing).
Furthermore, the Clock Selection Register 1 (CSR1) can be reloaded at the beginning of the phase2 by the 2Clk0 and its decoders shall be ready to select a glitch free phase1 sub-clock which is defined by any binary content of the CSR1.
Similarly the CSR2 is reloaded by the 1Clk0, in order to select a single glitch free sub-clock belonging to the phase2.
The second PS implementation method is based on adjusting alignment between an exit point of the synthesized clock from the reference propagation circuit versus an input reference clock; in a way which adds gate delays for phase increases, and subtracts gate delays for phase decreases. The second method is presented in FIG. 4A , and its differences versus the FIG. 4 are explained below.
The moving exit point from the driven by Fsync/2Dsel phase locked delay line is used as a return clock for the PLL×2Dsel multiplier, instead of using a fixed output of the INV0 to be the PLL return clock.
The fixed output of the INV0 is divided by the programmable frequency divider (PFD) in order to provide the synthesized clock Fsynt, instead of the moving synthesized clock selection point.
The first method exit point alignments, introduce phase jumps which cause synthesized clock jitter. The second method configuration shown in FIG. 4A , filters out Fsynt jitter frequencies which are higher than a bandwidth of the multiplier's PLL.
While any of the two PS implementation methods is shown above using a particular type of a reference clock propagation circuit, the PS comprises using all the listed below reference clock propagation circuits by any of the two methods:
an open ended delay line built with serially connected logical gates or other delay elements; a ring oscillator built with serially connected logical gates or other delay elements, which have propagation delays controlled in a PLL configuration;
a delay line built with serially connected logical gates or other delay elements, which have propagation delays controlled in a Delay Locked Loop (DLL) configuration.
It shall be noticed that further splitting to more than 2 parallel phases is actually easier than the splitting to the original 2 processing phases; because while one of the phases is active, its earlier sub-clocks can be used to trigger flip-flops which can segregate sub-clocks which belong to multiple other phases and can be used to drive the other parallel phases.
Consequently using this approach; allows increasing parallel stages processing times to multiples of reference clock periods, and provides implementation of said DWS MSC multiple phase processing which has been introduced in the previous section.
Said selection of a sub-clock for synthesized clock timing, can be physically implemented in two different ways:
by using phase producing gates from linv0 to linvR and from linv0 to linvR, as having 3state outputs with enable inputs EN, one of which is enabled by one of the outputs of the sub-clock selection gates from 1sel0 to 1selR and from 2sel0 to 2selR;
or by using the sub-clock selection gates which have all their outputs connected into a common collector configuration (instead of having them followed by the 3 state gates), in order to allow a currently active output of one of the sub-clock selection gates to produce a phase of the synthesized clock FselN.
The PS comprises fractional adjustments of synthesized clock phase for providing high resolution phase modifications by fractional parts of a reference clock period.
The PS comprises combined periodical and fractional adjustments of synthesized clock phase, which use counters of reference clock periods for generating counter end (CE) signals when a periodical part of a phase adjustment is expired.
The PS further comprises using said counter end signals for generation of control signals which assign and/or synchronize consecutive parallel processing phases for processing consecutive combined or fractional phase adjustments of the synthesized clock.
The PS comprises:
Using a basic periodical adjustment and a basic fractional adjustment for providing a basic phase step, which can remain the same for multiple edges of the synthesized clock. Using a modulating periodical adjustment and a modulating fractional adjustment, which can be different for every specific edge of the synthesized clock. Using said DWS MSC and SSPP methods for processing of said basic periodical adjustments, basic fractional adjustments, modulating periodical adjustments and modulating fractional adjustments for calculating periodical and fractional parts of combined adjustments.
Processing of said calculated combined adjustment with a positioning of a synthesized clock previous edge for calculating a periodical and a fractional part of the next edge position of the synthesized clock.
7. Frame Phase Detector
The Frame Phase Detector (FPD) operates as follows:
local clock phase is measured continuously by counting time units signaled by the local clock; abstract frame, consisting of time intervals defined by software, is used for high resolution measurements of local clock phase error versus an external clock phase defined by it's frame signaled by external events, wherein such time intervals expected by software and expressed in local time units are subtracted from time intervals, occurring between said external events, measured in local clock units; resulting phase error is read back by software subroutines.
Using such software defined frame instead of using an equivalent frame produced by hardware is advantageous, as it eliminates circuits and errors associated with using such electrical local frame and allows instant phase adjustments to be applied after the arrival of the external frame thus resulting in more stable DPLL operations.
Furthermore such software frame is more suitable for time messaging protocols such as IEEE 1588.
Subtracting a nominal number of local clock cycles corresponding to an imaginary frame has been anticipated by Bogdan in U.S. Pat. No. 6,864,672 wherein basic circuits and timing diagrams are shown, however this invention comprises further contributions, such as:
more comprehensive programming of said software frame, in order to allow timing adjustments in more complex systems with rapidly changing references frequencies and references phase hits; programmable presetting of numerical first edge allows elimination of an initial phase error when phase error measurements begun, in order to enable the use of the FPD for very precise delay measurements in critical traffic control applications; elimination of any accumulation of digitization errors with an alternative solution simpler than presently existing arrangement.
The FPD comprises solutions described below.
1. A frame phase detector (FPD) for measuring a frame phase skew between a first frame consisting of a programmable sequence of expected numbers of sampling local clocks, and a second frame defined with a series of time intervals located between second frame edges defined by changes of an external frame signal or by changes of a frame status signal driven with external messages such as time stamps, wherein a frame measurement circuit captures a number of said sampling clocks occurring during an interval of the second frame and a phase processing unit subtracts the captured number from the expected number representing expected duration of the corresponding interval of the first frame; wherein-the frame phase detector comprises:
a means for a detection of said second frame edges, by detecting said changes of the external frame signal, or by detecting said changes of the frame status driven by the external messages; the frame measurement circuit using the sampling local clock, which is a higher frequency signal, to measure said time intervals of the second frame having lower frequency, wherein the frame measurement circuit counts said sampling clocks occurring during every interval of the second frame and captures and buffers the counted value until it is read by a phase processing unit; the phase processing unit for subtracting the expected number of the sampling clocks from the counted number of the sampling clocks, in order to calculate an interval phase skew between the expected interval of the first frame and the corresponding interval of the second frame. a means for combining said interval phase skews of particular frame intervals into said frame phase skew.
2. A frame phase detector as described in statement 1, wherein said second frame begins with a numerical first edge, representing initial phase of the second frame, defined as a number of sampling delays between an expected location of such numerical first edge and the first counted sampling clock, wherein the frame measurement circuit is preset to the numerical first edge before any said counting of the sampling clocks takes place; the frame phase detector comprising:
a means for presetting the frame measurement circuit to said numerical first edge before said counting of the sampling periods of the first interval of the second frame takes place; a means for supplementing said preset numerical first edge by adding following sampling periods counted until the second edge of the second frame is encountered, and a means for capturing and buffering a resulting total number of sampling periods until it is read by a phase processing unit; wherein the resulting total number of the sampling periods represents duration of such first interval of the second frame and is made available for further processing.
3. A frame phase detector as described in statement 1 receiving an incoming wave-form carrying the external frame signal or carrying the external message; the frame phase detector wherein:
said detection of the second frame edges from the incoming wave-form, is performed by a circuit synchronized with the local sampling clock and producing a known propagation delay.
4. An FPD as described in statement 1, wherein the frame phase skew is calculated without any accumulation of digitization errors of said intervals phase skews while the single intervals phase skews are still available for intermediate signal processing; the FPD comprising:
a means for rounding said counted number of the sampling periods by adding 1 such sampling period to the counted number defining length of said frame interval, wherein ½ of the added sampling period approximates a fraction of the sampling period occurring before said counting of the interval sampling periods and another ½ of the added sampling period approximates a fraction of the sampling period occurring after said counting; whereby such addition of 1 sampling period to every interval measurement, provides all sampling periods occurring between said counted numbers of sampling periods relating to consecutive intervals of the second frame, and reduces a digitization error of any long frame to a time sampling error of a single interval.
5. A frame phase detector as described in statement 1 including a high resolution circuit for extending resolution of phase measurements below a period of the local clock, wherein the high resolution circuit propagates the local clock through a delay line built with serially connected gates producing different phases of the local clock; the frame phase detector comprising:
the high resolution circuit using a phase capture register for capturing a state of outputs of the serially connected gates, which the local clock is propagated through, at an edge of the interval of the second frame; or the high resolution circuit using a phase capture register for capturing an edge of the interval of the second frame by using the outputs of the serially connected gates as sampling sub-clocks applied to clocking-in inputs of the phase capture register while said second frame, defined with the frame signal or the frame status, is applied to data inputs of the phase capture register.
6. A frame phase detector as described in statement 1 including a high resolution circuit for extending resolution of phase measurements below the period of the local clock, wherein the high resolution circuit propagates the second frame, defined with the frame signal or the frame status, through a delay line built with serially connected gates producing different phases of the second frame; the frame phase detector comprising:
the high resolution circuit using a phase capture register for capturing a phase of an edge of the interval of the second frame by applying the outputs of the serially connected gates which the second frame is propagated through to data inputs of the phase capture register while the local clock is used for clocking the data inputs in; or the high resolution circuit using a phase capture register for capturing a phase of an edge of the interval of the second frame by using the outputs of the serially connected gates-which the second signal frame is propagated through-as clocking in signals while the local clock is applied to data inputs of the phase capture register.
7. A frame phase detector as described in statement 1 including a noise filtering edge detector (NFED) improving reliability and precision of said detection of the second frame edges by removing phase noise from wave-form edges and amplitude glitches from wave-form levels through continues over-sampling and digital filtering of an entire incoming wave-form carrying said external frame signal or said external messages, wherein the incoming wave-form is over-sampled with sampling sub-clocks generated by a delay line built with serially connected gates which the sampling local clock is propagated through, and wave-forms variable length pulses are processed by comparing an edge mask, which provides an expected pattern of wave-form samples corresponding to an edge of the wave-form, with a sequence of wave-form samples surrounding a consecutive analyzed sample; the FPD wherein the NFED further comprises:
a wave capturing circuit for capturing results of sampling the incoming wave-form in time instances produced by the outputs of the delay line which the sampling local clock is propagated through;
means for performing logical or arithmetic operations on particular samples of the edge mask and their counterparts from the wave-form samples surrounding the consecutive analyzed sample of the captured wave-form;
means for using the results of said operations for deciding if said operations can determine a filtered location of an edge of a filtered wave-form, wherein such filtered location is further used for said detection of boundaries of the second frame.
8. Noise Filtering Edge Detector
The NFED is directed to signal and data recovery in wireless, optical, or wireline transmission systems and measurement systems.
The noise filtering edge detector (NFED) provides digital filtering of waveform pulses transmitting serial streams of data symbols with data rates reaching ½ of maximum clock frequency of IC technology.
The NFED enables:
continues waveform over-sampling with sampling frequencies 5 times higher than the maximum clock frequency;
elimination of phase jitter from edges of the pulses and elimination of amplitude glitches from insides of the pulses as well;
and a system for adaptive noise filtering based on analysis of captured unfiltered portions of the over-sampled waveform.
The noise filtering edge detectors (NFED) shall be particularly advantageous in system on chip (SOC) implementations of signal processing systems.
The NFED provides an implementation of programmable algorithms for noise filtering for a very wide range of low and high frequency wave-forms.
The NFED is based on a synchronous sequential processor (SSP) which allows >10 times faster processing than conventional digital signal processors.
The NFED comprises:
the SSP used for capturing and real time processing of an incoming waveform (see the end of this Subsection); a wave-from screening & capturing circuit (WFSC) (see the end of this Subsection); a programmable control unit (PCU) for supporting adaptive noise filtering and edge detection algorithms;
The NFED compares: a captured set of binary values surrounding a particular bit of a captured waveform, with an edge mask comprising a programmed set of binary values.
Such comparison produces an indicator of proximity between the surrounded bit and an expected edge of the waveform. The indicator is named edge proximity figure (EPF).
Said comparison comprises:
performing logical and/or arithmetic operation on any bit of the captured set and its counterpart from the edge mask; integrating results of said operations performed on all the bits of the captured set, in order to estimate the EPF for the surrounded bit; defining a waveform transition area by comparing the EPF with an edge threshold, wherein a set of bits having EPFs exceeding the threshold defines the waveform transition area where an edge is expected. Finding the most extreme EPF by comparing all the EPFs belonging to the same waveform transition area, wherein such EPF identifies a bit position localizing a filtered edge.
The NFED further comprises:
modulating locations of detected rising and/or falling waveform edges by an edge modulating factor (EMF) used to modify edge thresholds which are subtracted from the EPFs, wherein such reduced EPFs are used for finding edge location;
using an edge modulation control register (EMCR) programmed by the PCU, for defining function transforming said EMFs into said modifications of edge thresholds.
The NFED still further comprises displacing detected edges by a preset number of bits, in order to compensate for inter-symbol interference ISI or other duty cycle distortions.
The NFED further includes:
using the WFSC for programmable screening of the over-sampled unfiltered wave-form, and for capturing screened out wave-form intervals, and for communicating said captured intervals and other results to the PCU; programmable waveform analysis and adaptive noise filtering algorithms; edge mask registers for providing said edge masks used for detecting rising and/or falling waveform edges; edge threshold registers for providing said edge thresholds used for detecting rising and/or falling waveform edges; edge displacement registers for providing said edge displacement numbers used for shifting detected rising and/or falling edges by a programmable number of bits of waveform processing registers; filter control registers which control; said logical and/or arithmetic operations conducting the comparison of captured waveform bits with the edge mask, and said edge displacements in the processed waveforms; using the PCU for calculating and loading said edge mask registers and/or said edge threshold registers and/or said edge displacement registers and/or said filter control registers; using the PCU for controlling said calculations of the EMF by presetting the EMCR in accordance with adaptive noise filtering algorithms. using the PCU for controlling and using the WFSC operations for implementing adaptive filters by controlling noise filtering edge detection stages of the SSP.
Further description of the NFED is provided below.
The NFED comprises:
a wave capturing circuit for capturing an incoming wave-form sampled by sub-clocks produced by the outputs of the delay line which the sampling clock is propagated through; a circuit performing logical or arithmetic operations on particular samples of the edge mask and their counterparts from the wave-form samples surrounding the consecutive analyzed sample of the captured wave-form; using the results of said operations for defining a filtered location of an edge of the waveform.
Such NFED further comprises:
a filter arithmometer for comparing the edge mask with the captured wave-form in order to introduce noise filtering corrections of the edges of the filtered wave-form; a filter mask register providing the edge mask which is compared with the captured wave-form of an input signal and/or filter control register which provides code for controlling operations of said filter arithmometer in order to provide said corrections of the filtered wave-form.
The NFED compares said edge mask samples of the expected edge pattern with samples from a consecutive processed region of the captured wave-form.
Consequently the NFED comprises:
accessing any said consecutive processed region of the captured wave-form and using such region as comprising samples corresponding to the edge mask samples; selection of a consecutive sample from the edge mask and simultaneous selection of a corresponding consecutive sample from the processed region of the captured wave-form; calculating a correlation component between such selected samples by performing an arithmetical or logical operation on said selected samples; calculating a digital correlation integral by adding said correlation components calculated for single samples of the edge mask.
The NFED includes calculating correlation integrals for said consecutive processed regions uniformly spread over all the captured wave-form, wherein the calculated correlation integrals are further analyzed and locations of their maximums or minimums are used to produce said filtered locations of said edges of the filtered wave-form;
Such NFED operations comprise:
moving said processed region by a programmable number of samples positions of the captured wave-form; storing and comparison of said correlation integrals calculated for different processed regions, in order to identify said maximums or minimums and their locations; using said locations of said maximums or minimums for producing the filtered locations of the edges of the filtered wave-from.
The NFED includes compensation of inter-symbol interference (ISI) or other predictable noise by adding a programmable displacement to said filtered location of the edge of the wave-form.
Therefore the NFED comprises:
programmable amendment of the filtered location of the wave-form edge by presetting said programmable displacement with a new content; using such newly preset displacement for shifting the filtered location of the next detected edge.
The NFED includes compensation of periodical predictable noise with programmable modulations of said filtered locations of the wave-form edges by using an edge modulating factor (EMF) for a periodical diversification of said edge thresholds corresponding to different said regions of the wave-form; wherein the NFED comprises:
modulation of the filtered locations of the wave-form edges by using the edge modulating factor (EMF) for modulating said edge thresholds; subtracting such modulated thresholds from the correlation integrals calculated in said different wave-form regions; using such reduced correlation integrals for locating said maximums defining locations of filtered edges. whereby said EMF provides such modulation of the edge thresholds, that predictable noise introduced to consecutive wave-form samples by known external or internal sources, is compensated.
The NFED further includes:
using an edge modulation control register (EMCR) programmed by the PCU, for said modulation of the edge thresholds.
The NFED comprises:
sequential processing stages configured into a sequential synchronous processor driven synchronously with said sampling clock.
The NFED further comprises parallel processing phases implemented with said synchronous sequential processors; wherein:
said parallel processing phases are driven by clocks having two or more times lower frequencies than said sampling clock; consecutive parallel phases are driven by clocks which are shifted in time by one or more periods of said sampling clock;
The NFED comprises using multiple noise filtering sequential stages in every parallel processing phase for extending said wave-form filtering beyond a boundary of a single phase.
Such NFED further includes an over-sampled capturing of consecutive wave-form phases in corresponding phases wave registers which are further rewritten to wave buffers with overlaps which are sufficient for providing all wave samples needed for a uniform filtering of any edge detection despite crossing boundaries of the wave buffers which are loaded and used during different said phases; wherein the NFED comprises:
rewriting the entire wave register belonging to one phase into the wave buffer of the same phase and rewriting an end part of said wave register into a front part of the next phase wave buffer, while the remaining part of the next wave buffer is loaded from the wave register belonging to the next phase; whereby every wave buffer contains entire said wave-form regions needed for calculating said EPF's corresponding to the samples belonging to the phase covered by this buffer.
The NFED includes:
merging of said parallel processing phases, wherein multiple said parallel processing phases are merged into a smaller number of parallel phases or into a single processing phase, when passing from one said sequential processing stage to the next sequential stage. splitting of said parallel processing phases, wherein one said processing phase is split into multiple parallel processing phases or multiple parallel processing phases are split into even more parallel phases, when passing from one said sequential processing stage to the next sequential stage.
The NFED includes said PCU for analyzing results of said real time signal processing form the SSP and for controlling operations of the SSP; wherein the PCU comprises:
means for reading results of captured signal processing from the SSP; means for programming the filter mask register and/or the filter control register and/or said presetting of the programmable displacement and/or the edge modulating factor, which are applied for achieving said filtering of the captured wave-forms.
The NFED includes a wave-form screening and capturing circuit (WFSC) for capturing pre-selected intervals of unfiltered over-sampled wave-form; wherein the WFSC comprises:
using programmable screening masks and/or programmable control codes for verifying incoming wave-form captures for compliance with said programmable screening masks. buffering captured wave-form for which the pre-programmed compliance or non-compliance has been detected, or for counting a number of said detections; communicating said buffered wave-form and a detections counter to the PCU.
The PCU reads resulting captured signals from the WFSC and controls operations of the WFSC; wherein the PCU comprises:
programming the screening masks and/or the control codes for performing said verification of captured wave-forms compliance or non-compliance with said screening patterns; reading verification results and/or reading captured wave-forms which correspond to the preprogrammed verification criteria.
The NFED includes using said PCU for adaptive noise filtering; wherein the PCU comprises:
means for programmable waveform analysis; means for loading edge mask registers which provide said edge masks used for detecting rising and/or falling wave-form edges; or means for loading edge threshold registers which provide said edge thresholds used for detecting rising and/or falling waveform edges; or means for loading edge displacement registers which provide said edge displacements used for shifting detected rising and/or falling edges by a programmable number of samples positions of the captured wave-form; or means for loading filter control registers which control said logical and/or arithmetic operations conducting the comparison of captured wave-form samples with the edge mask, and said edge displacements in the processed wave-forms; or means for controlling said EMF by presetting the EMCR in accordance with adaptive noise filtering algorithms.
General definition of the SSP is provided below.
The SSP includes real time capturing and processing of in-coming wave-form and a programmable computing unit (PCU) for controlling SSP operations and supporting adaptive signal analysis algorithms.
Said SSP comprises an over-sampling of incoming wave-form level by using a locally generated sampling clock and its sub-clocks generated by the outputs of serially connected gates which the sampling clock is propagated through. If an active edge of the wave-form is detected by capturing a change in a wave-form level, the position of the captured signal change represents an edge skew between the wave-form edge and an edge of the sampling clock.
In addition to the above wave-form capturing method, the SSP includes 3 other methods of the edge skew capturing which are defined below:
the sampling clock captures the outputs of serially connected gates which the incoming wave-form is propagated through; the outputs of serially connected gates which the incoming wave-form is propagated through, provide wave-form sub-clocks which capture the sampling clock. the incoming wave-form captures the outputs of serially connected gates which the sampling clock is propagated through;
The above mentioned edge skew capturing methods further include:
using falling edges of said sub-clocks for driving clock selectors which select parallel processing phases during which positive sub-clocks are enabled to perform said edge skew capturing, or using rising edges of said sub-clocks for driving selectors which select parallel processing phases during which negative sub-clocks are enabled to perform said edge skew capturing; using serially connected clock selectors for enabling consecutive sub-clocks, in order to assure that consecutive sub-clocks will target appropriate consecutive bits of appropriate capture registers. The SSP invention includes using said serially connected gates: as being an open ended delay line; or being connected into a ring oscillator which can be controlled in a PLL configuration; or being connected into a delay line which can be controlled in a delay locked loop (DLL) configuration.
Every said edge skew amounts to a fraction of a sampling clock period.
The SSP comprises measuring time intervals between active wave form edges, as being composed of said edge skew of a front edge of the incoming waveform, an integer number of sampling clock periods between the front edge and an end edge, and said edge skew of the end edge of the wave-form.
The SSP further comprises a parallel multiphase processing of incoming signal by assigning consecutive parallel phases for the capturing of edge skews and/or processing of other incoming wave-form data with clocks which correspond to consecutive sampling clocks.
Consequently the SSP invention comprises using 1 to N parallel phases which are assigned for processing incoming signal data with clocks corresponding to sampling clock periods numbered from 1 to N, as it is further described below:
circuits of phase1 process edge skews or phase skews or other incoming signal data with a clock which corresponds to the sampling clock period number 1; circuits of phase2 process edge skews or phase skews or other incoming signal data with a clock which corresponds to the sampling clock period number 2; finally circuits of phase N process edge skews or phase skews or other incoming signal data with a clock which corresponds to the sampling clock period number N.
Said parallel multiphase processing allows N times longer capturing and/or processing times for said multiphase stages, compared with a single phase solution.
The SSP includes parallel stage processing of incoming signal by providing multiple processing stages which are driven by the same clock which is applied simultaneously to inputs of output registers of all the parallel stages.
The SSP further comprises a synchronous sequential processing of incoming signal by using multiple serially connected processing stages with every stage being fed by data from the previous stage which are clocked-in by a clock which is synchronous with the sampling clock.
Since every consecutive stage is driven by a clock which is synchronous to the same sampling clock, all the stages are driven by clocks which are mutually synchronous but may have some constant phase displacements versus each other.
The SSP further comprises:
merging of processing phases which occurs if multiple parallel processing phases are merged into a smaller number of parallel phases or into a single processing phase, when passing from a one processing stage to a next processing stage; splitting of processing phases which occurs if one processing phase is split into multiple processing phases or multiple processing stages are split into even more processing stages, when passing from a one processing stage to a next processing stage.
The SSP includes a sequential clock generation (SCG) circuit which uses said clock selectors and said sub-clocks: to generate SSP clocks which drive said parallel phases and said sequential stages, and to generate selector switching signals for said merging and splitting of processing phases.
The SSP includes time sharing of said parallel phases: which is based on assigning a task of processing of a newly began wave-form pulse to a next available parallel processing phase.
The SSP comprises a sequential phase control (SPC) circuit, which uses results of a wave edge decoding and said SSP clocks, for performing said time sharing phase assignments and for further control of operations of an already assigned phase.
The SSP comprises passing outputs of a one parallel phase to a next parallel phase, in order to use said passed outputs for processing conducted by a following stage of the next parallel phase.
The outputs passing is performed: by re-timing output register bits of the one phase by clocking them into an output register of the next parallel phase simultaneously with processing results of the next parallel phase.
The SSP further comprises all the possible combinations of the above defined: parallel multiphase processing, parallel stage processing, synchronous sequential processing, merging of processing phases, splitting of processing phases, and outputs passing.
The SSP includes processing stage configurations using selectors, arithmometers, and output registers, which are arranged as it is defined below:
input selectors select constant values or outputs of previous stages or outputs of parallel stages or an output of the same stage to provide arithmometer inputs, and arithmometer output is clocked-in to an output register by a clock which is synchronous to the sampling clock; multiple arithmometers are fed with constant values or outputs of previous stages or outputs of parallel stages or an output of the same stage, and an output selector selects an arithmometer output to be clocked-in to an output register by a clock synchronous to the sampling clock; the above defined configuration as being supplemented by using an output of an output selector of a parallel processing stage for controlling output selector functions.
Proper arrangements of said parallel and sequential combinations and said stages configurations provide real time processing capabilities for very wide ranges of signal frequencies and enable a wide coverage of very diversified application areas.
Summary of the WFSC is provided below (see the Subsection 4 of the next section for preferred embodiment of WFSC).
The wave-form screening and capturing circuits (WFSC) comprises:
using programmable data masks and programmable control codes for verifying incoming wave-form captures for compliance or non-compliance with a pre-programmed screening patterns; buffering captured data for which the pre-programmed compliance or non-compliance have been detected; counting a number of the above mentioned detections; communicating both the buffered captured data and the number of detections, to an internal control unit and/or to an external unit; using programmable time slot selection circuits for selecting a time interval for which wave-form captures shall be buffered and communicated to the PCU.
Said PCU comprises implementation of the functions listed below:
programming of verification functions and patterns for checking captured wave-forms for compliance or non-compliance with the patterns; reading verification results and reading captured wave-forms which correspond to the preprogrammed verification criteria; reading captured wave-forms which can be pre-selected by the PCU arbitrarily or based on other inputs from the SSP; programming of noise filtering functions and noise filtering masks for filtering captured wave-forms; reading results of real-time wave-form processing from the SSP, processing the results and providing control codes and parameters for further real-time wave-form processing in the SSP, in accordance with adaptive signal processing algorithms; reading output data from the SSP, interpreting the data, and communicating the data to external units.
9. Summary of SCCS
SCCS introduced above comprises methods, systems and devices described below (listed as claims in PCT/CA2006/001120).
1. A phase synthesizer providing programmable modifications of a phase of a synthesized clock by unlimited number of gate delays per a modification step with step resolution matching single gate delay at steps frequencies ranging from 0 to ½ of maximum clock frequency; the phase synthesizer comprising:
a delay control circuit connected to a programmable control unit (PCU) wherein the delay control circuit defines size and frequency of phase delay modifications of the synthesized clock versus a reference clock, the delay control circuit also having a terminal connected to reference sub-clocks generated by a reference propagation circuit or connected to odd/even sub-clocks generated by an odd/even phase selector; the reference propagation circuit, connected to the reference clock, consisting of serially connected gates wherein outputs of the gates generate the reference sub-clocks providing variety of phase delays versus the reference clock; an odd/even phase selector, connected to the reference sub-clocks, for splitting the reference sub-clocks by generating separate odd sub-clocks and even sub-clocks, wherein the odd sub-clocks begin during odd cycles of the reference clock and the even sub-clocks begin during even cycles of the reference clock; a clock selection register loaded by the odd sub-clocks and by the even sub-clocks with the outputs of the delay control circuit, wherein the odd sub-clocks or the even sub-clocks beginning during an earlier cycle of the reference clock download outputs of the delay control circuit which select the even sub-clocks or the odd sub-clocks beginning during a later cycle of the reference clock for providing the synthesized clock; an output selector connected to the output of the clock selection register and to the outputs of the odd/even phase selector, wherein the output selector uses inputs from the clock selection register for selecting output of the odd/even phase selector which is passed through the output selector for providing the synthesized clock.
2. A phase synthesizer providing programmable modifications of a phase of a synthesized clock by a programmable number of gate delays per a modification step with step resolution matching single gate delay at steps frequencies ranging from 0 to ½ of maximum clock frequency, wherein uncontrolled phase transients inherent for frequency synthesizers are eliminated; the phase synthesizer comprising:
a reference propagation circuit, connected to a reference clock, consisting of serially connected gates wherein outputs of the gates generate reference sub-clocks providing variety of phase delays versus the reference clock; a delay control circuit, connected to a programmable control unit (PCU) and to the reference propagation circuit, for applying phase delay modifications of the synthesized clock versus a reference clock by modifying selections of said reference sub-clocks chosen for sourcing the synthesized clock; the PCU, connected to an interrupt signal generated by the delay control circuit, for supplying programmable sequences of said phase delay modifications in response to interrupt signals sent by the delay control circuit.
3. A noise filtering edge detector (NFED) for recovering digital signal transitions and their phases from noisy waveforms while assuming ideal signal shape between the transitions, in order to identify digitally transmitted data, by continues over-sampling and digital filtering of the incoming waveform based on comparing an edge mask, representing an expected pattern of wave-form samples corresponding to an edge of the original wave-form, with a sequence of wave-form samples surrounding a consecutive analyzed sample; the NFED comprising:
a wave capturing circuit for capturing results of sampling the incoming wave-form in time instances produced by the outputs of the delay line which the sampling clock is propagated through; a correlation calculating circuit for performing logical or arithmetic operations on particular samples of the edge mask and their counterparts from a wave samples region surrounding the consecutively analyzed sample of the captured wave-form, in order to calculate a correlation integral between the wave samples region and the edge mask; a proximity estimating circuit for deciding if there is an edge occurrence at the consecutively analyzed sampling instant based on processing of such correlation integrals calculated for samples belonging to a surrounding wave region.
4. A noise filtering edge detector (NFED) for recovering digital signal transitions and their phases from noisy waveforms while assuming ideal signal shape between the transitions, in order to identify digitally transmitted data, by continues over-sampling and digital filtering of the incoming waveform based on comparing an edge mask, representing an expected pattern of wave-form samples corresponding to an edge of the original wave-form, with a sequence of wave-form samples surrounding a consecutive analyzed sample; the NFED comprising:
a wave capturing circuit, connected to a sampling clock and to the incoming waveform, for continues over-sampling of the incoming wave-form; a correlation calculating circuit for performing logical or arithmetic operations on particular samples of the edge mask and their counterparts from a wave samples region surrounding the consecutively analyzed sample of the captured wave-form, in order to calculate a correlation integral between the wave samples region and the edge mask; a proximity estimating circuit for deciding if there is an edge occurrence at the consecutively analyzed sampling instant based on processing of such correlation integrals calculated for samples belonging to a surrounding wave region.
5. A hybrid phase locked loop (HPLL) producing a stable low jitter output clock while enabling very high frequency multiplication factor which can be programmed to any real number belonging to a continues range from 1 to tens of thousands, wherein a low frequency reference clock multiplied by such factor produces such HPLL output clock while a desirable preprogrammed phase and frequency transfer function (PFTF) is maintained by a micro-controller (MC); the HPLL comprising:
an analog phase locked loop (APLL) having one input of it's analog phase detector (APD) connected to the HPLL output clock while another APD input is connected to a local synthesized clock produced by a local phase synthesizer (LPS) connected to the HPLL output clock; a frame phase detector (FPD) for measuring a digital phase error between the output clock and the reference clock, wherein such digital phase error is read by said micro-controller which controls operations of said local phase synthesizer; a digital phase locked loop (DPLL) comprising the frame phase detector and the micro-controller and the local phase synthesizer, wherein the MC drives said local phase synthesizer into producing phase differences between the APD inputs needed for implementing said preprogrammed PFTF between the output clock and the reference clock.
6. An open-ended software controlled synchronizer (OE-SCS) using micro-controller (MC) subroutines for providing programmable phase frequency transfer function (PFTF) between a reference clock and an output clock generated by a phase synthesizer totally avoiding uncontrolled phase transients inherent for frequency synthesizers, wherein such phase synthesizer works in an open loop configuration enabling inherently stable generation of said output clock and maintains low phase jitter of the output clock independent of phase jitter levels in the reference clock; the OE-SCS comprising:
a frame phase detector (FPD) measuring digital phase error between a local clock and said reference clock; the MC for reading said digital phase error and for processing it and for driving said phase synthesizer into generating the output clock implementing said PFTF between the output clock and the reference clock; the phase synthesizer, connected to a local clock and controlled by the MC, for producing said output clock in the open loop configuration.
7. The OE-SCS configuration of claim 6 further including an external synchronization mode (ESM) enabling analog phase locking of the output clock to an external clock which can be provided by a local reference clock or an output clock from a backup synthesizer unit, wherein such OE-SCS with ESM comprises:
an analog PLL (APLL-ESM), connected alternatively to the phase synthesizer output clock or to such external clock, for producing such phase locked output clock.
8. The OE-SCS configuration of statement 7, wherein the APLL-ESM further comprises:
a reference selector (RFS) for selecting the phase synthesizer output clock or said external clock as sourcing an APLL-ESM reference clock which the output clock has to be phase locked to.
9. A heterodyne timing configuration of a software controlled synchronizer (HTC-SCS) using a local oscillator which can have very low frequency and a micro-controller (MC) for securing programmable phase frequency transfer functions (PFTF) between a reference clock and an output clock while enabling very high frequency multiplication factor which can be programmed to any real number belonging to a continues range from 0 to tens of thousands, wherein very low phase jitter of the output clock is maintained independent of phase jitter levels in the reference clock; the HTC-SCS comprising:
a frame phase detector (FPD) for measuring a digital phase error between the reference clock and the output clock; the MC for reading the digital phase error and for implementing the PFTF by controlling operations of a phase synthesizer defining analog phase errors produced by an analog phase detector (APD) of an analog phase locked loop (APLL), wherein such analog phase errors control phase and frequency of the output clock produced by the APLL; the phase synthesizer, controlled by the MC while connected to the output clock and supplying an input of the APD, for introducing the analog phase errors programmed by the MC; an analog phase locked loop (APLL), having one input connected to the output of the phase synthesizer while another input is connected to the output clock, for generating said output clock; a digital phase locked loop (DPLL) using the FPD and the MC and the phase synthesizer for controlling operations of the APLL in order to implement the PFTF between the output clock and the reference clock.
10. The HTC-SCS of statement 9 further including the HPLL of statement 5 in order to multiply a very low frequency of an inexpensive local oscillator to much higher frequency range needed to synthesize the output clock required; such configuration comprising:
an additional frame phase detector (A-FPD) for measuring a digital phase error between the output clock and the local oscillator applied as an additional reference clock; an additional DPLL subroutine in the MC for implementing another PFTF applicable to the relation between the output clock and the additional reference clock.
11. The HTC-SCS of statement 9 further including an external synchronization mode (ESM) enabling analog phase locking of the output clock to an external clock which can be provided by a local reference clock or an output clock from a backup synthesizer unit, wherein such HTC-SCS with ESM comprises:
an additional clock selector (CLK-SEL) inserted between the output clock and said another input of the APLL for providing alternative selection of the output clock or such external clock for being connected to said another input of the APLL.
12. The OE-SCS configuration of statement 6 or the HTS-SCS of statement 9 further including the NFED of claim 4 for time domain phase noise filtering from an external reference waveform in order to produce a filtered reference waveform used further on as the reference clock, wherein the NFED can enable by one order more accurate phase detection when the external reference waveform is coming from a noisy serial link such as those utilized by network time protocols; wherein such synchronizer configuration comprises:
the NFED circuit, controlled by the MC and connected to the MC and to the external reference waveform, for producing the filtered reference waveform which is further used as the reference clock by the synchronizer.
13. The OE-SCS configuration of statement 6 or the HTS-SCS of statement 9 further including a time stamp decoder (TSD) circuit for decoding time stamp messages received from a remote serial link in order improve accuracy of phase/frequency detection by eliminating timing uncertainties caused otherwise by interrupts decoding software sub-routines; wherein such synchronizer configuration comprises:
the time stamp decoder, connected to a serial link receiver recovering a message signal, for producing time stamp messages communicated to the MC and for signaling time stamp detections to the FPD; network time protocol subroutines residing in the MC for reading the digital phase errors occurring between message signal transitions and for reading the time stamp messages and for controlling operations of the phase synthesizer; wherein such MC subroutines implement said programmed PFTF between the output clock and the reference clock signal defined with pulses occurring between those message signal transitions which are specified by stamp messages as signaling arrivals of such stamp messages.
14. A frame phase detector (FPD) for measuring a frame phase skew between a first frame consisting of a programmable expected number of sampling local clocks, and a second frame defined with a series of time intervals located between second frame edges defined by changes of an external frame signal or by changes of a frame status driven with external messages such as time stamps, wherein a frame measurement circuit captures a number of said sampling periods occurring during an interval of the second frame and a phase processing unit subtracts the captured number from the expected number representing expected duration of the corresponding interval of the first frame; wherein-the frame phase detector comprises:
a circuit for a detection of said second frame edges, by detecting said changes of the external frame signal, or by detecting said changes of the frame status driven by the external messages; the frame measurement circuit using the sampling local clock, which is a higher frequency signal, to measure said time intervals of the second frame having lower frequency, wherein the frame measurement circuit counts said sampling periods occurring during every interval of the second frame and captures and buffers the counted value until it is read by a phase processing unit; the phase processing unit for subtracting the expected number of the sampling periods from the counted number of the sampling periods, in order to calculate an interval phase skew between the expected interval of the first frame and the corresponding interval of the second frame. a circuit and/or a subroutine for combining said interval phase skews of particular frame intervals into said frame phase skew.
15. A frame phase detector as described in statement 14, wherein said second frame begins with a numerical first edge, representing initial phase of the second frame, defined as a number of sampling delays between an expected location of such numerical first edge and the first counted sampling clock, wherein the frame measurement circuit is preset to the numerical first edge before any said counting of the sampling clocks takes place; the frame phase detector comprising:
a circuit for presetting the frame measurement circuit to said numerical first edge before said counting of the sampling periods of the first interval of the second frame takes place; a circuit and/or a subroutine for supplementing said preset numerical first edge by adding following sampling periods counted until the second edge of the second frame is encountered, and a means for capturing and buffering a resulting total number of sampling periods until it is read by a phase processing unit; wherein the resulting total number of the sampling periods represents duration of such first interval of the second frame and is made available for further processing.
16. A frame phase detector as described in statement 14 receiving an incoming wave-form carrying the external frame signal or carrying the external message; the frame phase detector wherein:
said detection of the second frame edges from the incoming wave-form, is performed by a circuit synchronized with the local sampling clock and producing a known propagation delay.
17. An FPD as described in statement 14, wherein the frame phase skew is calculated without any accumulation of digitization errors of said intervals phase skews while the single intervals phase skews are still available for intermediate signal processing; the FPD comprising:
a circuit and/or a subroutine for rounding said counted number of the sampling periods by adding 1 such sampling period to the counted number defining length of said frame interval, wherein ½ of the added sampling period approximates a fraction of the sampling period occurring before said counting of the interval sampling periods and another ½ of the added sampling period approximates a fraction of the sampling period occurring after said counting; whereby such addition of 1 sampling period to every interval measurement, provides all sampling periods occurring between said counted numbers of sampling periods relating to consecutive intervals of the second frame, and reduces a digitization error of any long frame to a time sampling error of a single interval.
10. Receiver Synchronization Techniques
RST comprises methods and systems utilizing said referencing frame for achieving substantially more accurate and more stable of synchronization OFDM receiver to composite signal frame.
Furthermore RST comprises methods and systems enabling more accurate recovery of said referencing frame from OFDM data tones only and thus RTS enables both; better accuracy and improved efficiency resulting from elimination of preambles or pilots needed previously.
RST includes a method, a system and an apparatus for recovering said referencing frame signal from received composite frames carrying transmitted data or control pilot information, and for using such recovered referencing frame for synchronizing timing and frequency of receiver's local oscillator and data recovering circuits.
The RST comprises a method for recovering a referencing frame signal from OFDM composite frames carrying transmitted data or control pilot information, and for using such recovered referencing frame for synchronizing timing and frequency of receiver's local oscillator and data sampling circuits wherein a recovered frame lengths of such referencing frame interval represents a combined length of single or multiple composite frame intervals originating this referencing frame interval; wherein such RST comprises:
detection of boundaries of the data carrying frames or pilot frames by processing received OFDM composite signal or a recovered sub-carrier signal; using such boundaries detections for specifying said referencing frame signal, wherein such detections delimit said referencing frame interval; calculating a lengths difference between the recovered frame length and a measured frame length wherein such measured frame length of an equivalent symbol frame is the combined length of symbol frame intervals corresponding to said composite frame intervals originating this referencing frame, wherein the symbol frame defines a set of composite signal samples belonging to the same OFDM composite frame; calculating frequency offset between the referencing frame and such equivalent symbol frame by dividing such lengths difference by the recovered frame lengths or by the measured frame lengths; using such frequency offset for adjusting frequency of said local oscillator in order to maintain frequency alignment between a local oscillator clock and an OFDM transmitter clock; using such length difference for measuring a time offset between the composite frame and the symbol frame; using such time offset to synthesize phase of the symbol frame from the local oscillator clocks, in order to maintain correct time alignment between the symbol frame and the composite signal frame.
The RST further comprises:
application of time or frequency domain filters and/or statistical methods for evaluating reliability of such boundary detection, wherein: if said boundary detection signal is evaluated as reliable, it is used for delimiting said referencing frame interval corresponding to said single or multiple symbol frames; if said boundary detection signal is dismissed as unreliable, said measured frame length of equivalent symbol frame is increased by the length of symbol frame interval corresponding the composite frame interval which the boundary detection has failed for.
The RST further includes a frequency locked phase synthesis (FLPS) method and system for producing said symbol frame maintaining frequency and phase alignment to said referencing frame providing frequency and phase transmittal from an external source, wherein a frequency locked loop utilizes said local oscillator clock for producing frequency aligned symbol frame and a programmable phase synthesizer utilizes such local oscillator clock for producing the frequency and phase aligned symbol frame; wherein such FLPS comprises:
measuring a frequency error between the referencing frame and the symbol frame; using such frequency error for maintaining frequency alignment between the symbol frame and the referencing frame by controlling frequency of said local oscillator clock; presetting said phase synthesizer to an initial phase displacement needed to maintain a phase alignment between the referencing frame and the symbol frame; measuring a phase error between the referencing frame and the symbol frame; using such phase error for maintaining said phase alignment between the symbol frame and the referencing frame by controlling phase synthesis functions of said phase synthesizer from the local oscillator clock.
Such RST methods systems and apparatus are described below.
The RST comprises:
detection of boundaries of the data carrying frames or pilot frames by processing received OFDM composite signal or recovered sub-carrier signal; using such boundaries detections for specifying said referencing frame signal, wherein such detections delimit referencing frame interval and/or are utilized to define a nominal number of local oscillator output clocks expected to occur during such interval if frequency offset between the local oscillator clock and a transmitter clock equals zero;
The RTS further comprises using such referencing frame signal for measuring a normalized phase skew (equal to said frequency offset) and said time offset between the receiver and transmitter, wherein:
the local oscillator clock is counted during such referencing frame interval, and the counted value is buffered until it is used for calculating a phase skew between a local oscillator interval consisting of said nominal number of local oscillator clocks and the referencing frame interval; said phase skew is calculated as equal to a difference between the counted number of said local oscillator clocks and the nominal number; said normalized phase skew is calculated by dividing such phase skew by the nominal number; such normalized phase skew is used for synchronizing local oscillator frequency to a transmitter oscillator frequency; time offset is measured utilizing a phase difference between the referencing frame and a receiver symbol frame which defines a set of composite signal samples carrying an OFDM symbol, or between the referencing frame and an local oscillator frame consisting of the nominal number of said local oscillator clocks; such time offset is used to synthesize phase of the receiver symbol frame from the local oscillator clocks, in order to maintain correct time displacement between the receiver symbol frame and the composite signal frame.
The RST includes using such boundary detections for defining referencing frame intervals corresponding to multiple composite frames detected and thus such inter-detection intervals can represent multiple OFDM symbol intervals.
Accuracy of time offset measurement (evaluating timing difference between such boundary detection and a corresponding boundary of local symbol frame) is determined by a pilot/preamble form and/or processing method used.
Said frequency offset (equal to the normalized phase skew) measured over referencing frame interval is derived by dividing said phase skew, detected within the interval, by the expected interval length specified by the nominal number.
Accuracy of such phase skew detection is similar to that of the time offsets, since all of them are defined using said boundary detections.
Consequently such use of said referencing frame consisting of such prolonged intervals, greatly improves accuracy of frequency offset measurements.
RST includes:
maintaining known or predictable processing delay between reception of composite frame samples supplying direct or embodied definition of composite frame boundary, and a detection signal of such frame boundary produced by said synchronous processor operating synchronously with the local oscillator while processing such composite signal samples;
The RST further comprises:
using the synchronous sequential processing method and circuit (such SSP is defined in Subsection 8 of SUMMARY OF THE INVENTION), for implementing such synchronous processor maintaining said known or predictable processing delay.
RST comprises application of time or frequency domain filters and/or statistical methods for evaluating reliability of such boundary detections, wherein:
if said boundary detection signal is evaluated as reliable, it is used for delimiting said referencing frame interval corresponding to a singular or multiple said received symbol frames; if said boundary detection signal is dismissed as unreliable; an expected filtered lengths of said symbol frame period specifies generation time of a signal delimiting said referencing frame interval, or said nominal number of local oscillator clocks, corresponding to zero frequency offset within the last symbol frame, is added to said nominal number, corresponding to zero frequency offset within the current referencing frame interval, instead of generating such delimiting signal.
The RST covers both versions explained below:
utilizing said conventional DSP techniques and processors, implemented already by conventional solutions for the time offset measurement, for the detection of composite frame boundaries; or using said real-time synchronous processing techniques for such detection of composite frame boundaries (by ˜10× more accurate than that of such conventional DSP techniques).
Even if such conventional less accurate boundary detection is implemented; said RTS frequency offset measurement (10 times more accurate) will similarly improve amount of time offset introduced between consecutive boundary detections. Therefore time offset tracking and protection from any inter-symbol interference will be greatly improved as well, despite implementing such less accurate boundary detection.
RST includes an inherently stable frequency locked phase synthesis (FLPS) method and system producing said symbol frame maintaining frequency and phase alignment to a referencing frame providing frequency and phase transmittal from an external source, wherein a frequency locked loop utilizes an oscillator for producing a frequency aligned oscillator clock and a programmable phase synthesizer utilizes such frequency aligned oscillator clock for producing the frequency and phase aligned symbol frame (see FIG. 13 and FIG. 15 ); wherein:
the oscillator clock is counted during an interval of the referencing frame, and the counted value is buffered until it is used for calculating a phase skew between an oscillator nominal frame, consisting of a nominal number of said oscillator clocks, and said referencing frame, wherein the nominal number is such number of oscillator clocks which is expected to occur during such referencing frame interval if the phase skew equals zero; said phase skew is calculated as equal to a difference between the counted number of said oscillator clocks and the nominal number; if said referencing frame intervals are expected to have varying lengths specified by their nominal numbers varying accordingly, a normalized phase skew is calculated by dividing such phase skew by the nominal number assigned to such interval; said phase skew or normalized phase skew is applied back to the oscillator, in order to maintain said frequency alignment of the oscillator clock to the referencing frame; the referencing frame is applied to the phase synthesizer which utilizes said such oscillator clock for synthesizing said symbol frame maintaining frequency and phase alignment to the referencing frame; wherein such phase synthesizer (PS) (described in Subsections 5 and 6 of SUMMARY OF THE INVENTION) has its phase synchronization acquisition initialized by presetting initial phase of the synthesized frame (as it is exemplified in Subsection 5 of DESCRIPTION OF THE PREFERRED EMBODIMENT).
Furthermore RST comprises a second version of the FLPS offering better stability than that of conventional phase locked loops combined with highly accurate phase control (see FIG. 14 ); wherein the last step of the described above first version is replaced with the 2 steps listed below:
phase error (time offset) is measured as a phase difference between the referencing frame interval and a symbol frame interval produced by the phase synthesizer; such phase error is applied back to the phase synthesizer which utilizes said oscillator clocks for synthesizing the symbol frame maintaining frequency and phase alignment to the referencing frame.
Such phase synthesizer can be implemented; by utilizing methods and circuits defined in said Subsections 5 and 6 of this section.
Such second version comprises using much simpler phase synthesizer (without phase jitter control & reduction), which can be implemented as modulo (nominal-number) counter of oscillator clocks wherein such phase error is applied as counter preset value.
In addition to the stability improvements, both FLPS versions explained above enable by one order (˜10×) faster acquisition of frequency/phase alignment than that of conventional configurations for phase/frequency synchronization or control.
Such much faster synchronization acquisition shall be advantageous; in reducing mobile phone hand-over losses, or improving reliability of Wi/Fi or WiMAX connection switching.
RST comprises methods and systems enabling recovery of referencing frame phase (i.e. time offset) from OFDM data sub-carriers (or tones) only, without any use of bandwidth consuming preambles or pilot tones needed in conventional solutions.
Such phase (time offset) recovery from data sub-carriers (PRDS) methods comprise using said real-time synchronous processing techniques for recovering amplitudes and phases of sinusoidal cycles or half-cycles of a sub-carrier (tone) selected as being most reliable based on previous training session and/or on-fly channel evaluation. Such synchronous processing techniques are shown in the U.S. 60/894,433 claimed as priority application.
Such synchronous processing performed in phase with OFDM waveform capturing circuit, uses frequency sampling filters for recovering time domain sinusoidal representations of two tones (sub-carrierss) elected as being reliable enough and spaced sufficiently in frequency domain.
Every half-cycle of such recovered sinusoid identifies phase and amplitude of the tone (or sub-carrier) signal.
Such redundancy enables using statistical and deterministic filtering methods, much more efficient than DFT/FFT averaging effect, for selecting the half-cycle supplying most reliable and accurate tone parameters.
Such in phase synchronous processing implementing said SSP is used to provide said time domain recovery of only one or several such tones (sub-carriers), selected to facilitate said recovery of the referencing frame.
Such in phase processing assures maintaining said known or predictable processing delay between; said reception of composite frame, and said detection signal of referencing frame boundary.
By evaluating amplitudes and/or phases of such recovered sinusoidal cycles or half-cycles, said received symbol boundary is detected when correlation between consecutive amplitudes and/or phases recovered falls down after maintaining a middle-symbol plateau, thus indicating the end of the received symbol frame.
Such in phase synchronous processing enables recovery of single half-cycles of said selected sub-carrier. Therefore the phase of the end of last negative half-cycle recovered during such symbol frame, can be treated as the end boundary E B of this symbol frame.
Furthermore such ending phase enables detection of the received symbol boundary (time offset) with accuracy by ˜10× better than that of conventional solutions, when a data coding phase displacement C D of such selected tone is recovered and used to correct this ending phase, as it is explained below.
For a displacement code D C equal to 0, 1, 2 or 3, and for tone period T T , such coding displacement C D shall be calculated as:
C
D
=
D
C
T
T
4
Plurality of half-cycles detected over symbol interval supplies a lot of redundant timing information about in phase processed tones (sub-carriers). If another selected tone T2 is similarly in phase processed, than both tones coding displacements (C DT1 for T1, C DT2 for T2) can be calculated by analyzing time delay T KT1-KT2 measured between T1 cycle number K T1 and T2 cycle number K T2 .
Such displacement code can be calculated first as explained below:
T
KT
1
-
KT
2
=
K
T
1
·
T
T
1
+
C
DT
1
-
(
K
T
2
·
T
T
2
+
C
D
T
2
)
,
consequent
ly
:
D
CT
1
T
T
1
4
-
D
CT
2
T
T
2
4
=
T
KT
1
-
KT
2
-
(
K
T
1
·
T
T
1
+
K
T
2
·
T
T
2
)
=
Δ
,
D
CT
1
=
D
CT
2
T
T
2
T
T
1
+
Δ
4
T
T
1
wherein final D CT1 digit can be derived by substituting D CT2 =0, 1, 2, 3 into the above equation and by choosing for D CT1 this one of integers 0, 1, 2, 3 which is the closest to one of D CT1 values calculated with the above equation.
Knowing the D CT1 number said coding displacement of T1 can be calculated as:
C
DT
1
=
D
CT
1
T
T
1
4
It shall be noticed that if Tone 1 frequency is by 4 times greater than that of Tone 2; than the multiplier T T2 /T T1 =4 and consequently a time delay between a T1 cycle and closest to it T2 cycle supplies the value of the coding displacement C DT1 directly.
Furthermore in phase tones processing circuits implemented using said SSP techniques, define efficient and accurate registration of such time delays (between neighbor cycles of different tones), which can represent said direct C DT1 measurement.
RST comprises methods and systems enabling referencing frame phase recovery from OFDM data sub-carriers with ˜10× greater accuracy than that of conventional solutions without even requiring said preambles or pilot tones; wherein such high accuracy phase recovery (HAPR) method comprises steps listed below:
said in phase processing techniques are used for recovering amplitudes and phases of sinusoidal cycles or half-cycles of selected sub-carriers (tones), wherein such in phase processing assures maintaining said known or predictable processing delay between; said reception of composite frame, and said detection signal of referencing frame boundary; delay time between sinusoidal cycles of different selected tones is registered and used to recover data coding displacements occurring in the selected tones of the received composite frame; an approximate symbol frame boundary is detected by evaluating amplitudes and/or phases of such recovered sinusoidal cycles or half-cycles, when correlation between consecutive amplitudes and/or phases recovered falls down after maintaining a middle-symbol plateau, thus indicating the end of the received symbol frame; a phase of last cycle of such recovered sinusoidal tone is derived by analyzing amplitudes and/or phases of said sinusoidal cycles or half-cycles recovered before the end of symbol frame; an accurate symbol boundary is derived by correcting such phase of last cycle with the data coding displacement.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 Shows an Open Ended Configuration of Software Controlled Clock Synchronizer.
FIG. 2 Shows Open Ended Configuration of SCCS with External Synchronization Mode
FIG. 3 Shows Heterodyne Timing Configuration of SCCS enabling acceptance of very. range of referencing clock frequencies.
FIG. 4 Shows Sequential Clocks Generator (SCG) and Output Selection Circuits (OSC) enabling high resolution selections of mutually overlapping sub-clocks.
FIG. 4A Shows Sequential Clocks Generator (SCG) and Return Selection Circuits (RSC), lowering output clock jitter
FIG. 5 Shows Timing Control (TC) and Clocks Equalization (CE), which control timing of high frequency switching of synthesized clock
FIG. 6 Shows Synchronous Sequential Phase Processor (SSPP), which performs programmable high-speed phase synthesis.
FIG. 7 Shows Timing Diagram of Phase Synthesizer.
FIG. 8 Shows Wave Capturing including Edge Regions (WCER), which enable continues capturing of a an oversampled high frequency waveform.
FIG. 9 Shows Sequential Clocks Generation for the NFED(SCG NFED), which provides mutually overlapping sub-clocks enabling high accuracy detection of noisy signal edges.
FIG. 10 Shows Noise Filtering Edge Detectors (NFED)
FIG. 11 Shows Wave Form Screening & Capturing (WFSC), which enables analysis of incoming noisy waveform facilitating adaptive noise filtering
FIG. 12 Shows Timing Diagrams of the WFSC.
FIG. 13 Shows a block diagram of Inherently Stable Synchronization System.
Notes referring to FIG. 13 , are provided below:
Boundary detection delay (Tbd) determines predictable part of referencing frame delay to OFDM composite frame. Frequency offset (Fos) is not affected by the boundary detection delays Tbd for as long as Tbd remains constant. In order to make up for the boundary detection delay, Phase Synthesizer (PS) positions Local Symbol Frame forward in time compared to Referencing Frame. Frequency offset Fos derived using counted number of sampling clocks (Fcnt) and the nominal number (Fnom), can be measured with over 10× greater accuracy if it is measured over a reference frame interval over 10× longer.
FIG. 14 Shows a block diagram of Synchronization System with Improved Stability.
Notes referring to FIG. 14 , are provided below:
Boundary detection delay (Tbd) determines predictable part of referencing frame delay to OFDM composite frame. Frequency offset (Fos) is not affected by the boundary detection delays Tbd for as long as Tbd remains constant. Time error (Terr) between local symbol frame and composite frame, amounts to boundary detection delay added to the phase error between reference frame and local symbol frame i.e. Ter=Tbd+(Trf−Is).
FIG. 15 Shows an Inherently Stable Frequency Locked Phase Synthesis system.
FIG. 16 Shows a similar FLPS system with its Frequency Detector utilizing local XTAL clock.
FIG. 17 Shows a similar FLPS with Improved Stability.
FIG. 18 Shows a similar FLPS but enabling more accurate generation of a synchronized clock.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
1. Phase Synthesizer
The above mentioned first PS implementation is selected for the preferred embodiment, and it is shown in the FIG. 4 , FIG. 5 , FIG. 6 and FIG. 7 .
The PS comprises wave timing definition, which includes two major components downloaded to the PS from the PCU:
basic less frequently changed phase adjustments, which can include both periodical adjustments and fractional adjustments, define more stable components of wave-form phase;
high frequency phase modulations, which can include both the periodical adjustments and the fractional adjustments, allow every leading edge phase and/or every falling edge phase to be modulated with a different modulation factor.
Said phase modulations are downloaded to the PS simultaneously in batches containing multiple different modulation factors, where every said batch refers to a series of consecutive wave edges.
The PS has internal selection circuits, which select and use consecutive modulation factors for modulating phases of consecutive edges.
In order to allow higher wave generation frequencies, 2 parallel processing circuits are implemented which use consecutive phase1/phase2 circuits for synthesizing phases of consecutive odd/even edges.
As it is shown in the FIG. 6 , said basic phase adjustments are loaded to the Periodical Number Buffer (PNB) and to the Fractional Number Buffer (FNB); where they remain unchanged until PS internal Modulations Counter (MC) reaches MC=0 condition.
On the other hand, said modulation factors M1, M2-M6, M7 are shifted left, by one factor for every new edge, in the Phase Modulation Buffers (PMB1/PMB2) for providing consecutive modulation factor needed for a next edge in the left end of the PMB1/PMB2.
Such updated modulation factor is then added to the basic phase adjustments and resulting modulated phase adjustments are downloaded into the Periodical Number Registers (PNR1/PNR2) and into the Fractional Number Registers (FNR1/FNR2).
In order to synthesize an actual position of a new edge of the synthesized waveform; said downloaded modulated phase adjustments need to be added to a current edge position, and the results of said addition are downloaded into the Periods Counters (PC1 or PC2) and into the Fractional Selection Register (FSR)
The Sequential Clocks Generator (SCG) and Output Selection Circuits (OSC) are shown in the FIG. 4 and have been already explained in the Subsection “6. General Definition of Phase Synthesizer” of the previous section.
The Clock Selection Register ½ (CSR1/CSR2) specifies a sub-clock which will be selected in a forthcoming Phase2/Phase1 cycle of the reference clock fsync.
In order to remain settled during a whole next cycle of the fsync, the CSR1/CSR2 registers are loaded by the early sub-clocks of the present Phase2/Phase1 cycle of the fsync.
The CSR1/CSR2 are loaded:
with a current content of the Fractional Selection Register (FSR) (shown in FIG. 6 ), if the LD_C1 or LD_C2 (Load Counter 1 or Load Counter2) signal indicates that an end period of the present phase adjustment is indicated by the C2E or C1E (Counter 2 End or Counter 1 End) accordingly (see FIG. 2 and FIG. 3 );
with the binary value 2 S −1=R+1 which exceeds ranges of the 1 st Clock Selector (1CS) and the 2 nd Clock Selector (2CS) and results in none of selectors outputs being activated and none of sub-clocks being selected during a following phase cycle.
The Timing Control (TC) circuits are shown in FIG. 5 , the resulting Timing Diagram of Phase Synthesizer (TDPS) is shown in FIG. 7 , and TC operations are explained below.
The LD_C1 signal enables loading of the Period Counter 1 (PC1) with a number of periods which the previous stages of the Synchronous Sequential phase Processor (SSPP) have calculated for the current phase adjustment.
Said download deactivates/activates the C1E signal if a downloaded value is (bigger than 1)/(equal to 1) accordingly. When said downloaded value is bigger than 1, the C1EN=1 enables decreasing the PC1 content by 1 at every leading edge of the Clk1.1 until the PC1=1 condition is achieved and is detected by the PC1-OVF Detector which signals it with the C1E=1 signal. It shall be noticed that: when a fractional part of a phase adjustment calculated in said FSR reaches or exceeds a whole period of the fsync, the overflow bit FSR(OVF)=1
is activated and switches the PC1=1-OVF DETECTOR from said 1 detection mode to a 0 detection mode which prolongs current phase adjustment by 1 fsync period.
The phase 2 control circuit is driven by the C1E and by the LD_C1, and controls phase 2 operations with signals LD_C2, LD_RE2, LD_BU2; as it is further explained below:
The first C1E activation period generates the LD_C2 signal, and is followed by setting the LDR2_which terminates the LD_C2. The LD_C2 signal; enables loading of PC2 with a periods number for the next phase adjustment, enables loading of the FSR with a fractional adjustment for the next phase adjustment, and enables a downloading of the FSR to the CSR1 or to the CSR2. The LDR2_FF=1 generates the leading edge of the LD_RE2 signal. The LD_RE2 signal clocks in; a new modified fractional adjustment to the Fractional Number Register 2 (FNR2), and a new modified periodical adjustment to the Periodical Number Register 2 (PNR2). When the period number loaded by the LD_C2 is counted down to its end by the PC2, the C2E signal activates the LD_C1 similarly as the C1E has activated the LD_C2. The LD_C1=1 resets both the C1E and the LDR2_FF in the next cycle; The LDR2_FF=0 generates the leading edge of the LD_BU2 signal. The LD_BU2 signal clocks in; a previous PMB2 content shifted left by S+1 bits, or a new PM[M6,M4,M2,M0] content from the PCU when the Modulations Counter (MC) is decoded as MC=0.
The phase 1 control circuit is similarly driven by the C2E and by the LD_C2; and similarly generates the LD_C1, LD_RE1, LD_BU1 signals for controlling phase1 operations.
The only differences in the phase 1 versus phase 2 operations, are specified below:
The LD_BU1 signal clocks in a decreased by 1 value to the MC which is the modulo 4 counter. The DECODER MC=0 generates the MC=0 signal which selects provided by the PCU; the Periodical Number (PN)/the Fractional Number (FN)/the Phase Modifications (PM) to be loaded into the Periodical Number Buffer (PNB/the Fractional Number Buffer/the Phase Modifications Buffer 1(PMB1) by the leading edge of the LD_BU1. The DECODER MC=1 generates the MC=1_INT interrupt signal to the PCU, which informs the PCU that all the above mentioned phase adjustment parameters have been already stored in the PS buffers and can be replaced by new phase adjustment parameters.
2. Heterodyne Timing Configuration
FIG. 3 shows the heterodyne timing configuration (HTC) according to the preferred embodiment. The HTC integrates both Digital PLLs (DPLLs) and Analog PLLs (APLLs) into a single CMOS ASIC, with the exception of the external VCXO which provides a stable clock (Fil_LocClk) having very low phase jitter.
Said APLL mode of the HTC is described below.
The Reference Selector (RFS) is programmed by the PCU to select one of the external reference clocks (Ext_RefClk). Such selected external reference clock is applied to the reference input of the Analog Phase Detector (APD) which drives the Loop Filter of the VCXO which provides the stable low jitter output f_filter.
The Fil_OutClk; drives the Output PLL (OUT_PLL), and is connected to the fsync/L input of the Return Clock Synthesizer (RET_PS) which is implemented with the PS embodiment described in the previous section.
The RET_PS synthesizes the RetClk, which is connected to the APD return input.
It shall be noticed that very wide ranges of the RET_PS frequency adjustments, enable the PCU to tune the RET_PS to any frequency which the selected external reference may have.
Said OUT_PLL generates the output reference clock (OutRef) which drives the Output Clocks Generator (OCG) which provides all the major HTC output clocks OutClk(T:1).
Since the OCG consists of frequency dividers having very tightly controlled and well matched propagation delays, all the OutClk(T:1) are phase aligned with the Fil_OutClk and between themselves.
The DPLL mode of the HTC is described below.
The Fil_OutClk signal is programmed to be selected by the RFS for the APD reference signal, and the RET_PS provides the APD return signal which is synthesized from the same Fil_OutClk signal. One of the external reference waveforms (Ext_RefWfm) is selected by a selector controlled by the PCU for being processed by the NFED providing the filtered reference waveform (Fil_RefWfm), which is connected to the Time Stamp Decoder (TSD) and to the FPD1.
Local oscillator fixed output (LocOsc) is connected to the FPD2.
Both frame phase detectors FPD1/FPD2 shall use the high frequency sampling clock (SampClk) for accurate digital measurements of the PhaErr1 and the PhaErr2.
Said sampling clock is generated by the frequency multiplier OutRefxR from the OutRef generated by the OUT_PLL.
Since the OutClk(T:1) output clocks are phase aligned with the OUT_PLL ouput clock OutRef, and the sampling clock SampClk is phase aligned with the OutRef as well; the SampClk is phase aligned with the HTC output clocks OutClk(T:1).
The FPD1 measures a phase error between the sampling clock SampClk and the Ext_RefWfm, as Δφ1=φ_samp−φ_wfm.
The FPD2 measures a phase error between the sampling clock SampClk and the LocOsc, as Δφ2=φ_samp−φ_osc.
The PCU reads the measured phase errors and uses the RET_PS to introduce digital phase displacements between the APD reference input and the APD return input which will drive the VCXO based PLL for providing required phase transfer functions between the Fil_OutClk and the Ext_RefWfm.
Since the Fil_OutClk drives the OUT_PLL which has much higher BW than the VCXO PLL and the OUT_PLL determines phase of the OutClk, the OutClk implements the same phase transfer function as the Fil_OutClk.
Based on the measurements of Δφ 1 and Δφ 2 , the PCU calculates said Periodical Numbers (PN), Fractional Numbers (FN) and Phase Modifications (PM) which need to be provided to the Return Phase Synthesizer (RET_PS); in order to achieve a preprogrammed transfer function between the HTC output clocks and the selected DPLL reference clock Ext_RefWfm.
HTC free-run and hold-over modes use the above described DPLL mode configuration, as it is described below.
In the free-run mode; the PCU uses the phase error measurements for calculating phase differences which need to be inserted via the RET_PS for providing said OutClk locking to the local oscillator LocOsc.
In the hold-over mode; the PCU inserts phase differences via the RET_PS which cause the OutClk to maintain its last frequency displacement versus the LocOsc.
3. Noise Filtering Edge Detectors
The preferred embodiment implements the above defined general components of the NFED and is shown in FIG. 8 , FIG. 9 and FIG. 10 .
The NFED comprises over-sampling and capturing of consecutive wave-form intervals in specifically dedicated consecutive wave registers, wherein odd intervals are written into the wave register 1WR and even intervals are written into the wave register 2WR. Therefore incoming stream of samples is split into the two parallel processing phases (sometimes named as parallel synchronous pipelines). The first processing phase begins in the wave register 1WR and the second begins in the register 2WR. Such splitting into 2 parallel phases obviously doubles cycle time available in the sequential stages following the register 1WR and in the stages following the 2WR as well.
A sequential clock generation circuit (SCG) shows a method for splitting a steady stream of mutually overlapping sub-clocks spaced by a gate delay only into sub-sets of sub-clocks active during their dedicated phases only and non-active during all other phases. Such subsets are obviously used for providing timing for their dedicated phases.
The wave register 1WR is further split into 2 parallel sub-phases and the 2WR is split into other 2 parallel sub-phases, for the purpose of quadrupling cycle time available in said sub-phases (see the FIG. 8 showing the wave registers 1WR, 2WR followed by the wave buffers 11WB, 12WB, 21WB, 22WB).
In order to provide all wave samples needed for the filtering edge detection along a whole wave buffer, the NFED includes rewriting:
the end part 2WR(R:(R−M+1) of the wave register 2WR, into the front parts 11WB(M:1), 12WB(M:1) of the wave buffers 11WB, 12WB; the end part 1WR(R:(R−M+1) of the wave register 1WR, into the front parts 21WB(M:1), 22WB(M:1) of the wave buffers 21WB, 22WB.
The preferred embodiment is based on the assumptions listed below:
the wave registers 1WR and the 2WR are 15 bit registers (i.e. R=14); the rising edge mask REM(M:0) and the falling edge mask FEM(M:0) are 8 bit registers (i.e. M=7) and the PCU loads the same masks equal to 00001111 to both mask registers; the rising edge threshold RET is loaded with 0110 (6 decimal), and the falling edge threshold FET is loaded with 0010 (2 decimal);
The digital filter arithmometers 21DFA1/22DFA1/11DFA1/12DFA1 perform all the comparison functions, between the edge mask registers REM/FEM and the waveform buffers 21WB/22WB/11WB/12WB involving the edge threshold registers RET/FET, with the 3 basic operations which are further explained below.
The first operation is performed on all the waveform bits and involves the edge mask bits as it is specified below:
For every waveform buffer consecutive bit WB k the surrounding bits WB k−4 , WB k−3 , WB k−2 , WB k−1 , WB k , WB k+1 , WB k+2 , WB k+3 are logically compared with the mask bits B 0 , B 1 , B 2 , B 3 , B 4 , B 5 , B 6 , B M and the resulting 8 bit binary expression BE k (7:0) is created as equal to;
BE k (0)=(WB k−4 =B 0 ), BE k (1)=(WB k−3 =B 1 ), BE k (2)=(WB k−2 =B 2 )
BE k (3)=(WB k−1 =B 3 ), BE k (4)=(WB k =B 4 ), BE k (5)=(WB k+1 =B 5 )
BE k (6)=(WB k+2 =B 6 ), BE k (7)=(WB k+3 =B 7 ).
The second operation adds arithmetically all the bits of the binary expression BE k (7:0) and the resulting edge proximity figure EPF k is calculated as equal to EPF k =BE k (0)+BE k (1)+BE k (2)+BE k (3)+BE k (4)+BE k (5)+BE k (6)+BE k (7) which shall amount to a 0-8 decimal number. During the first and the second operations: all bits of any particular wave buffer have their specific edge proximity figures calculated at the same time during a cycle assigned for one of the arithmometers 21DFA1/22DFA1/11DFA1/12DFA1 attached to that buffer.
Since there are 15 bits in every wave buffer every such arithmometer consists of 15 parallel micro-arithmometers, wherein each such micro-arithmometer performs operation on an 8 bit edge mask and on 8 bit wave region.
Since this arithmometers perform the most intense processing, said quadrupling of cycle time by gradual splitting from the original 1 phase into the present 4 parallel phases was needed.
The third operation performs functions explained below:
In order to carry the same level from the last bit of the previous phase DFR1 into the following bits of the present phase digital filter register2 (DFR2), the last bit DFR1(R) of the previous DFR1 is always rewritten into the carry bit DFR1(C) of the present DFR1 and is used by the digital filter arithmometer2 (DFRA2) to fill front bits of the DFR2 with the same level as the last bit of the previous phase DFR1. The verification is made if the EPF k indicates a rising edge condition by exceeding the content of the rising edge threshold RET(T:0). Consequent detection of the EPF k >RET=6 condition, sets to level=1 the corresponding DFR1 k bit of the DFR1 and all the remaining bits of the present DFR1 until a falling edge is detected as it is explained below. The verification is made if the EPF k indicates a falling edge condition by being smaller than the content of the falling edge threshold FET(T:0). Consequent detection of the EPF k <RET=2 condition, sets to level=0 the corresponding DFR1 k bit of the DFR1 and all the remaining bits of the present DFR1 unless a rising edge is detected as it explained above.
The digital filter arithmometers 21DFA2/22DFA2/11DFA2/12DFA2 perform; the inter-phase continuation of filling front bits of the present phase register in accordance with the level set in the last bit of the previous phase, followed by said edge displacement which compensates for duty cycle distortions due to inter-symbol interference (ISI), etc.
The edge displacement comprises the 3 basic operations described below.
Any DFR1 rising edge, indicated by a level 0 to 1 transition, is shifted left by a number of bits specified by a content of the rising edge displacement register (RED(D:0)) loaded by the PCU in accordance with its filtering algorithms. Any DFR1 falling edge, indicated by a level 1 to 0 transition, is shifted left by a number of bits specified by a content of the falling edge displacement register (FED(D:0)) loaded by the PCU in accordance with its filtering algorithms. In order to propagate said displacement operations from the present phase to the previous phase; the propagated sign of the edge bit (DFR2(Sp)) and the propagated bits (DFR2(Dp:0)), are calculated by the DFA2 and are written down into the DFR2 extension DFR2(Sp,Dp:0).
In order to propagate said displacement operations from the next phase DFR2 into end bits of the present phase digital filter register3 (DFR3); the propagated sign of the edge bit and the propagated displaced bits DFR2(Sp,Dp:0) from the next phase, are used by the digital filter arithmometer3 (DFRA3) to fill end bits of the digital filter register3 (DFR3) with the correctly displaced bits propagated form the next phase to the present phase.
4. Wave-Form Screening and Capturing
The wave-form screening and capturing (WFSC) of screened out intervals is performed by the circuits which are shown in FIG. 11 and the timing diagrams of the WFSC are shown FIG. 12 .
The WFSC allows the PCU to perform screening and capturing of the incoming signal, for timing intervals which correspond roughly to a period of a single data bit, based on a content of the wave buffers 11WB, 12WB, 21WB and 22WB.
The WFSC allows the PCU to screen signal quality of incoming wave form, by applying programmable screening functions using programmable data masks, as it is listed below:
content of said wave buffers can be verified for compliance or non compliance with a mask provided by the PCU, based on verification functions and verification tolerances which are programmed by the PCU; if any wave buffer verification detects preset by PCU screening out criteria to be met, the corresponding content of a wave buffer is captured and made available for PCU for further analysis; in addition to the wave buffer capturing, a number of said screened out results will be counted and communicated to the PCU as well.
In addition to the above mentioned screening; the WFSC allows also the PCU to select arbitrarily a content of any of the wave buffers during any particular time slot; for being captured and made available for analysis by the PCU.
The above mentioned signal screening is implemented by the WFSC, as it is explained below. The Mask Detection Arithmometrs (11MDA and 12MDA) for the WFSC are positioned similarly as the DFAs of the NFED.
The second stage uses the mask detection arithmometers 11MDA/12MDA for identifying wave-forms which are beyond usually acceptable range defined by the PCU.
The programmable control unit (PCU) determines logical and/or arithmetical processing which the 11MDA/12MDA shall perform, by pre-loading the detection control register (DCR) with a control code applied as the DCR(P:0) to the 11MDA/12MDA.
Additionally the PCU determines the mask DMR(R:0) which the captured data 11WB(R:0)/12WB(R:0) shall be processed against, by pre-loading the detection mask register (DMR). The 11SEL signal equal to 1/0 selects; the 11WB(R:0)/12WB(R:0) to be downloaded to the phase one detected data buffer (1DDB) by the clock 1Clk2 (see FIG. 11 and FIG. 12 ), if the 11DET/12DET indicate detection of a pre-selected mask by the mask detection arithmometer 11DMA/12DMA.
At the beginning of the next time frame, which has 128 phase1 cycles, the last captured 1DDB content is further downloaded to the phase1 data register (1DDR) by the clock signal 1Clk3/128. Number of said mask detections is counted in the mask counter buffer (1MCB), as it is explained below:
at the beginning of every time frame which has 128 phase1 cycles, the 1MCB is reset/preset to 0/1 if there isn't/is a mask detection for the first cycle of the frame which is signaled by the 1PHA/128ena=1; the 1MCB is increased by 1/kept the same, if there is/isn't any mask detection during a particular phase1 cycle; at the beginning of the next time frame, the 1MCB is downloaded to the phase1 mask counter register (1MCR) and the output of the 1MCB>0 decoder (MCB>0 DEC) is downloaded to the 1MCR(P) bit, by the 1Clk3/128.
Said 1DDR and 1MCR are read by the PCU, when the beginning of the next frame is communicated to the PCU by the phase1 128 th clock enable signal (1PHA/128ena) and the above mentioned 1MCR(P)=1 indicates that at least 1 detection of a pre-selected mask occurred during the previous frame.
Said PCU controlled capturing of a wave buffer content is implemented, as it is explained further below.
The sample number register (SNR) is loaded by the PCU: with a phase number defined as phase1/phase2 if the SNR(0) is set 0/1, and with a particular phase cycle number in a time frame defined by SNR(7:1) bits.
Since there are 2 phases with 128 cycles per time frame, SNR(7:0) bits define 1 of 256 sampling cycles for having its wave buffer captured and made available for a further analysis by the PCU. Said SNR is downloaded into the phase1 sample number buffer (1SNB) at the beginning of a time frame by the first phase1 clock of the frame 1Clk2/128.
At the beginning of a time frame: the phase1 sample number counter (1SNC) is set to 0, since the 1PHA/128ena selects 0 to be loaded into the 1SNC by 1Clk2.
During every other cycle of the time frame: 1 is added to the SNC content, since the 1PHA/128ena is inactive during all the next cycles of the frame.
The 1SNC(7:1) and the 1SNB(7:1) are being compared by the logical comparator (Log.Comp.), which produces the Eq=1 signal when their identity is detected.
Said Eq=1 enables the 1SNB(1)=0/1 to select the 11WB(R:0)/12WB(R:0) in the 3:1 selector (3:1 SEL), for capturing in the phase1 sampled data buffer (1SDB).
At the beginning of the next time frame, the output of the 3:1 SEL is additionally captured in the phase1 sampled data register (1SDR) by the signal 1Clk3/128.
Said 1SDR is read by the PCU, which is notified about availability of the requested sample by the signal 1PHA/128ena.
5. Receiver Synchronization Techniques
Functional block diagram of inherently stable synchronization system is provided in FIG. 13 wherein recovery of OFDM receiver sampling clock Cs and local symbol frame F1s is shown. More detailed implementation and partitioning of such system is shown in FIG. 15 .
Samples from an OFDM composite signal interval, long enough to comprise entire OFDM symbol, are processed by the Synchronous Sequential Processor (defined in Subsection 8 of SUMMARY OF THE INVENTION) which uses Cs as its reference clock (see FIG. 13 and FIG. 14 ).
Sub-clocks of such reference clock, driving such SSP used for OFDM processing, may not need to facilitate phase resolution matching single gate delay. Therefore a conventional delay line, consisting of serially connected flip-flops driven by a frequency multiplier of the reference clock, can be sufficient to generate such lower resolution sub-clocks instead of using the delay line consisting of serially connected gates with all elaborate timing involved.
However independent of any delay line implementation, SSP architecture guaranties that all SSP micro-operations are performed in exactly predefined time windows within known time displacements to such reference clock. Therefore SSP processing delay measured from entering last sample of an interval processed to producing the final result of such interval processing is totally predictable.
As specified therein, SSP includes real-time processing stages of incoming wave-form and a programmable computing unit (PCU) for supporting any adaptive signal processing dependent of previous micro-operations results or wave-form content.
SSP uses interrupts to acquire results of such PCU adaptive processing, while PCU produces such results in advance before they are needed (see also Subsection 8 of SUMMARY OF THE INVENTION). Therefore SSP can use such results in predefined time windows synchronizing known sequence of said SSP micro-operations, while PCU accommodates all changes of processing time and/or algorithms.
Since such SSP is used to detect composite frame boundary, resulting boundary detection delay Tbd is known very accurately.
Despite such accurate Tbd, composite signal distortions due to channel interference and inherent problems of conventional methods for composite frame boundary detection, shall be expected to cause noticeable errors in boundary detection times which convey into receiver time offset errors.
However said predictable Tbd of the boundary detection signal Sbd (see FIG. 13 ) facilitates generation of the referencing frame Fr, re-timed by the sampling clock Cs.
Such Fr is applied to the digital frequency detector (DFD) which produces frequency offset estimate Fos by subtracting said expected nominal number of sampling clocks form the number of sampling clocks counted during said referencing frame interval.
As such DFD arrangement facilitates measuring frequency offset within referencing frame intervals corresponding to multiple periods of OFDM composite frame, such prolongation of frequency sensing intervals multiples accuracy of frequency offset measurements (see also time-diagrams and Note 4 in FIG. 13 ).
Such much more accurate frequency offset Fos applied to the frequency locked loop FLL, enables generation of said sampling clock with frequency by one order more accurate and thus prevents any inter-bin leaking endangering IDFT/IFFT processing of OFDM composite frame.
Such DFD/FLL configuration offers other significant advantages as well over phase locked loops PLL used conventionally in OFDM receivers. Such configuration assures much faster frequency acquisition when connecting to new composite signal source, and avoids PLL instability when exposed to an unknown spectrum of phase noise caused by unpredictable channel interference and inaccuracy of conventional phase measurements methods.
Inherent stability is achieved by combining such stable sampling clock generation by FLL with the phase synthesizer PS (defined in Subsections 5 and 6 of SUMMARY OF THE INVENTION) working in the open ended configuration (shown in FIG. 13 and FIG. 15 ).
Such open ended PS configuration applies modifications of referencing frame phase with programmable phase steps defined by sub-clocks of sampling clock, wherein such sub-clocks are generated internally in PS from flip-flop based delay line driven by FreqDetClk produced by the frequency multiplier Samp-Clk×R of sampling clock Cs.
Such PS method (defined in the Subsections 5 and 6 mentioned above) uses the same SSP architecture as that used for the boundary detection discussed above. Similarly sub-clocks driving such SSP do not need to facilitate phase resolution matching single gate delay. Coincidentally sub-clocks used by PS for defining programmable phase steps applied to the local symbol frame do not need to provide phase resolution matching single gate delay either. Therefore the same sub-clocks, generated by conventional flip-flop based delay line, can be used for both; for driving said SSP utilized by SP, and for defining said programmable phase steps.
Such conventional delay line is used as consisting of serially connected flip-flops driven by the frequency multiplier Samp-Clk×R of the sampling clock wherein the sampling clock represents frequency multiplication of the local symbol frame (utilized as the reference clock by the SF_PS) by said nominal number Nn. Consequently total frequency multiplication factor amounts to R×Nn.
PCU produces such steps number definition before it is requested by PS and places such steps number on its output PCU-OUT in response to PS interrupt MC_INT.
PCU shown in FIG. 15 receives; the referencing frame Fr, the sampling clock Cs, the boundary delay time Tbd and said frequency offset Fos.
When synchronization acquisition is initialized, Fr presets an PCU internal Fr phase register to Nn-Tbd, wherein Nn is said nominal number expected for reference frame interval covering single OFDM symbol.
As such presetting of PCU internal Fr register provides said programmable presetting of numerical first edge specific for the FPD (see Subsection 7 of SUMMARY OF THE INVENTION), it utilizes such PCU function for upgrading this DPD to provide such FPD functionality.
At the same time the referencing frame prompts the PCU_OUT register to provide definition of such Nn-Tbd phase step, and prompts the symbol frame phase synthesizer SF_PS to generate PCU interrupt MC=1_INT and to implement such Nn-Tbd phase step.
Consequently the first edge of the Local Symbol Frame F1s is generated with the Nn-Tbd phase displacement to the initializing edge of Fr.
Dependent of specifics of a particular PS design;
such generation of F1s first edge displaced by Nn-Tbd phase step to the referencing frame edge, can include resetting the phase of frame generated previously by PS before such phase step is applied.
As PCU receives consecutive Fos values defining displacements of next detected Fr boundaries to consecutive expected boundaries, it keeps updating track record of previous Fos and said Fr phase register with such Fos values in order to maintain continues record of Fr phase changes and present status.
In order to avoid uncontrolled phase transients resulting from an accumulation of DFD digitization errors, only DFD design eliminating such digitization errors accumulation can be used (such DFD is defined in U.S. Pat. No. 6,864,672 by Bogdan).
Similarly PCU keeps also track record of previous phase steps defined to SF_PS and keeps updating its internal F1s phase register defining present phase of the local symbol frame.
Based on such data about Fr phase and F1s phase, PCU calculates a number of said phase steps which the referencing frame phase needs to be modified by, in order to implement a preprogrammed phase/frequency transient function between the local symbol frame and the referencing frame.
Such configuration enables accurate phase frequency control reducing phase noise and jitter.
In addition to the SF_PS, configuration shown in FIG. 15 uses another phase synthesizer FLL_PS placed in the return path of the analog phase locked loop APLL used to modify sampling clock frequency in order to minimize said frequency offset between the sampling clock and said composite signal clock.
Additionally to the data mentioned above, PCU keeps track of phase steps introduced into the sampling clock Cs via the FLL_PS. Therefore PCU has all the data defining frequency and phase relations between the sampling clock Cs and the crystal oscillator clock LX_Clk, and between the LX_Clk and said composite frame clock outlined by the referencing frame clock.
Similar configuration shown in FIG. 16 utilizes LX_Clk, instead of the sampling clock, for producing said Freq.DetClk. Therefore PCU scales said nominal number Nn, proportionally to frequency offset between the LX_Clk and the composite clock outlined by the Fr, before utilizing such Nn for measuring Fos with the DFD referenced by the LX_Clk.
Synchronization System with improved stability shown in FIG. 14 and FIG. 17 , includes:
using the additional DPD for measuring time offset (phase error) Trf-1s between the referencing frame Fr and the symbol frame F1s, instead of relying entirely on PCU subroutines explained above; such Trf-1s is supplied to PCU which uses it to maintain close control of such time offset (phase error) by defining appropriate phase steps to the symbol frame synthesizer SF_PS.
Such synchronization system can facilitate even closer control of such phase offset, while it implicates lesser stability improvements and simpler phase frequency control less efficient in reducing phase/frequency transients.
High Accuracy FLPS shown in FIG. 18 represents high performance synchronization system which will be needed in future high speed wireless/wireline OFDM and mobile receivers, including next generations of ADSL, WiFi or WiMAX.
Such system facilitates multiplying low frequency (down to 30 kHz) of XTAL oscillator (LX_Clk) by very high factor (up to 50 000), in order to utilize very inexpensive low frequency crystal cuts for producing highly stable local oscillator clock.
Such frequency multiplier utilizes DFD1 for measuring frequency error XTALos between the XTAL oscillator clock (LX_Clk) and the sampling clock Cs represented by the FreqDetClk, wherein the frequency multiplication factor R shall be lower than 10 in order to avoid stability problems in SOC PLL implementations.
PCU reads the frequency error XTALos and produces sequence of PCU-OUT signals supplied to the frequency locked loop phase synthesizer (FLL_PS) located in the reference path of VCXO based analog PLL having very low bandwidth (for example 0.1-1 kHz).
Such PCU_OUT signals cause said FLL_PS to insert phase errors which drive said analog PLL into producing sampling clock Cs maintaining pre-programmed frequency relation to the LX_Clk.
Since such PCU-OUT signals represent sequence of small phase steps applied with frequency by several orders higher than that of analog PLL bandwidth, resulting Cs jitter shall be very low.
Consequently, such system multiplies low frequency of highly accurate inexpensive local XTAL oscillator (LX_Clk), in order to produce sampling clock frequency with accuracy much better than 1 ppm.
Such system utilizes SCCS concept of multiplying low frequency of highly accurate inexpensive local XTAL oscillator, in order to produce sampling clock frequency with accuracy much better than 1 ppm (see Subsections 1, 2 and 3 of SUMMARY OF THE INVENTION).
This system combines all the advanced features, explained above for the FLPS shown in FIG. 15 , combined with such highly efficient frequency multiplication method.
CONCLUSION
In view of the above description of the invention and associated drawings, other modifications and variations will now become apparent to those skilled in the art based on the teachings contained herein. Such other modifications and variations fall within the scope and spirit of the present invention. | Clock recovery techniques (CRT) useful in a wide variety of communication systems based on wireless, optical and wireline links, include: a hybrid PLL (HPLL) enabling 1-50,000 frequency multiplication with very low output jitter independent of reference clock quality, a software controlled clock synthesizer (SCCS) for high accuracy phase & frequency synthesis producing synchronized low jitter clock from external time referencing clocks, waveforms or messages, receiver synchronization techniques (RST) contributing more accurate synchronization of receiver clock to OFDM composite frame combined with much faster acquisition time and better stability of the receiver clock. | Identify and summarize the most critical features from the given passage. | [
"This patent application is a continuation and claims priority benefit of U.S. patent application Ser.",
"No. 13/763,729 filed on Feb. 10, 2013, wherein the Ser.",
"No. 13/763,729 is the continuation and claims priority benefit of Ser.",
"No. 11/931,026 filed on Oct. 31, 2007 and issued as U.S. Pat. No. 8,374,075, wherein the Ser.",
"No. 11/931,026 is the continuation-in-part and claims priority benefit of international application No. PCT/CA2006/001120 filed on 27 Jun. 2006, wherein the Ser.",
"No. 13/763,729 and the Ser.",
"No. 11/931,026 applications are each hereby incorporated by reference in their entirety.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention This invention is directed to providing low cost high accuracy phase and frequency recovery techniques (PFRT) offering significantly better stability and accuracy in synchronizing systems and circuits in multiple fields including communication systems, distributed control, test and measurement equipment, and automatic test equipment.",
"Such PFRT comprises software controlled clock synchronizer (SCCS) which can be used in multiple fields exemplified above wherein said communication systems include communication networks for wireless or wireline or optical transmissions with very wide ranges of data rates.",
"The SCCS comprises further novel components such as;",
"programmable phase synthesizers (PS), precision frame phase detectors (FPD) of an incoming wave-form, and noise filtering edge detectors (NFED) for precise recovering of wave-form edges from noisy signals.",
"Furthermore: since said FPD and NFED define circuits and methods enabling ˜10 times faster and more accurate location systems than conventional solutions, they allow reliable location services for mobile and traffic control applications including fast movements at close ranges in noisy environments unacceptable for solutions.",
"Still furthermore this invention comprises receiver synchronization techniques (RST), utilizing a referencing frame, recovered from an OFDM composite signal, for synchronizing an OFDM receiver clock to a composite signal transmitter clock.",
"Background Art of Software Controlled Clock Synchronizer Conventional solutions for software controlled synchronization systems use software controlled digital phase locked loops (DPLLs) for implementing software algorithm minimizing phase errors and providing programmed transfer function between a DPLL output clock and a timing reference.",
"In conventional solutions said timing reference can be provided: as a conventional external clock connected to a digital phase detector, which compares it with the local clock in order to produce the digital phase error;",
"or with time stamp messages sent by an external source, initiating a capture of local clock time and communicating external clock timing corresponding to the captured local timing, wherein software is used for producing said digital phase errors by comparing the captured local timing with the communicated external timing.",
"However the conventional DPLL configurations have four major limitations listed below: 1.",
"DPLLs are inherently unstable if said timing reference comprises components having frequencies higher than ⅕ of the DPLL bandwidth.",
"Since time stamp messages are sent over regular communication links they are subjected to highly unpredictable time delay variations (TDVs) resulting from collisions between different packet streams sharing a common communication line.",
"Such unpredictable TDVs are bound to introduce timing reference components having unknown frequency spectrums, when said timing reference is provided by exchanging time stamp packages sent over shared communication link.",
"Resulting stability problems cause such conventional DPPL configurations to be highly unreliable in many applications.",
"Conventional digital phase detectors and said software algorithms minimizing phase errors, involve accumulation of phase digitization errors.",
"Such accumulation causes an uncontrolled phase drift of the output clock, when a software error minimization procedure is unable to recognize and eliminate persistent existence of an digitization error corresponding to a lasting unknown frequency error of the output clock.",
"Conventional digital phase detectors;",
"offer resolutions worse than that of phase steps limited by maximum clock frequency of IC technology, and they require complex processing for calculating precise phase skews when highly irregular edges of a reference timing are defined in newly emerging timing protocols such as IEEE 1588.",
"Similarly clock synthesizers have phase steps resolutions bounded by maximum clock frequency of IC technology and furthermore they use frequency synthesis method unable to provide high precision control of phase transients of synthesized clock.",
"Conventional clock synchronization systems require expensive local oscillators, expensive external off-chip analog components, and expensive IC technologies suitable for mixed mode operations;",
"in order to provide highly stable and low jitter synchronization clocks required in industrial control systems and in communication networks.",
"Temperature stable crystal oscillators are major cost contributors exceeding ⅔ of total costs of synchronization systems.",
"However in conventional solutions;",
"low cost highly stable crystal cuts can not be used, since their oscillation frequencies are to low to be transformed into a stable low jitter clock.",
"Conventional synchronization systems use digital phase detectors which are >5 times less accurate than this inventions FPD, and frequency synthesizers producing uncontrolled phase transients during any frequency switching and introducing 10 times less accurate phase steps than this inventions phase synthesizer PS.",
"Such frequency synthesizers are based on direct digital frequency synthesis (DDFS) method modifying average frequency of an output clock by periodical removal of a clock pulse from a continues stream of pulses.",
"Since said frequency synthesizers use over 10 times slower phase processing and introduce unknown numbers of 10 times less accurate phase steps than the PS, they are unable to perform any phase synthesis and produce uncontrolled phase transients during frequency switching and introduce much more jitter than the PS.",
"Consequently;",
"in order to limit phase transients to acceptable levels, said conventional synchronization systems are bound to work in closed loop configurations wherein output clock phase is subtracted from reference clock phase and resulting phase error is minimized by a programmable control unit driving frequency synthesizer producing said output clock 3.",
"Background Art of Receiver Synchronization Techniques Insufficient accuracy of conventional synchronization for OFDM receivers impose major limitations on OFDM communication quality (see Cit.",
"[1] and [2] listed below) and such limitations are compounded by rapidly growing data rates.",
"Some conventional solutions add specific preambles inserted into composite signal (Cit.",
"[3], [4], [5], and [6]).",
"Such preamble comprises similar parts having known phase (displacement in time) within the preamble.",
"Such preambles enable detection of symbol boundary time offset, by steps of: evaluating correlation functions between OFDM signal portions shifted properly in time until such similar preamble parts are detected;",
"using a phase of local clock frame marked by the similar parts detection and said known phase of such similar parts detected, for estimating time offset of the local frame;",
"estimating frequency offset of the local clock versus transmitter clock by analyzing said correlation functions between such preamble parts shifted properly in time.",
"Other synchronization solutions analyze correlation estimates of received pilot preambles or pilot tones with predefined pilot preambles or pilot tones (Cit.",
"[7]), in order to estimate time offset and frequency offset of the local clock frame.",
"However such use of preambles or pilots;",
"reduces system efficiency by using signal power that could otherwise have been used for transmitting data, and allows limited accuracy only due to such detection and estimates sensitivity to channel interference and insufficient data supplied in the preamble.",
"There are also pilot-less synchronization techniques.",
"One such pilot-less technique, named maximum likelihood (ML) method (Cit.",
"[8]), utilizes inherent redundancy in OFDM signal, by correlating parts of the signal with other parts having known positioning within frame (cyclic prefix).",
"However;",
"as such pilot-less technique uses statistical methods and depend on transmitted data patterns, they are even less accurate than those using preambles or pilots.",
"Another pilot-less technique calculates timing offset and frequency offset from displacements of tone phases caused by said timing and frequency offsets (Cit.",
"[9]).",
"Fundamental deficiency of conventional solutions characterized above is their inability to perform any accurate measurement of frequency offset;",
"due to their reliance on using phase offset observed over single preamble/pilot period only for the frequency offset estimation.",
"Such estimates degraded by unpredictable OFDM channel interference, can not be helped enough by averaging them for as long as each estimate is calculated over single preamble/pilot.",
"Still other significant deficiency of conventional synchronization is instability of their phase locked loops (used for phase and frequency tracking), caused by changing data patterns and/or unpredictable phase error components introduced into OFDM channel by generally unknown interference.",
"Such conventional synchronization solutions for OFDM receivers did not succeed in providing reliable and accurate recovery of a referencing frame providing time domain definition of phase and frequency of received OFDM composite frame.",
"However such referencing frame defined in time domain, is essential for achieving accurate control of local oscillator frequency offset and receiver time offset (receiver phase error).",
"OFDM composite signal has not been originally designed to carry distinctive edges enabling detection of composite frame boundaries, and conventional DFT/IDFT frequency domain processing is not well suited for any accurate detection of such boundaries occurring in time domain either.",
"Conventional DSP techniques and processors used are not equipped to perform real-time processing of OFDM signal needed to produce such referencing frame maintaining predictable accurate timing relation to the OFDM signal received.",
"Such major deficiencies of conventional solutions are eliminated by the RST as it is explained in Subsection 2 of BRIEF SUMMARY OF THE INVENTION.",
"CITATIONS [1] “Equalization for DMT-Based Broadband Modems”",
"by Thierry Pollet at al.",
", IEEE Communications Magazine, Volume 38, Issue 5, May 2000.",
"[2] “Retraining WLAN Receivers for OFDM Operation”",
"by Ivan Greenberg, CommsDesign, January 2002.",
"[3] “A Symbol Synchronization Algorithm for OFDM Systems”",
"by T. Salim at al.",
", Communication Systems and Networks ˜AsiaCSN 2007˜April 2007 [4] “Synchronization Approach for OFDM based Fixed Broadband Wireless Access Systems”",
"by M. Gertou, G. Karachalios, D. Triantis, K. Papantoni and P. I. Dallas, INTRACOM S. A., July 2005.",
"[5] “A Novel Scheme for Symbol Timing in OFDM WLAN Systems”",
"by Yong Wang at al.",
", ECTI Transactions on Electrical Eng.",
"Electronics and Communications, August 2005.",
"[6] “Performance of a novel carrier frequency offset estimation algorithm for OFDM-based WLANs”",
"by ZHAO Zhong-wei, Journal of Zhejiang University SCIENCE A, 2006 7(3).",
"[7] “Synchronization Schemes for Packet OFDM System”",
"by Haiyun Tang, Kam Y. Lau and Robert W. Brodersen, IEEE International Conference on Communications, May 2003.",
"[8] “ML Estimation of Timing and Frequency Offset in Multicarrier Systems”",
"by Jan-Jaap van de Beek, Magnus Sandell, Per Ola Borjesson, Lulea University of Technology, April 1996.",
"[9} “A Robust Timing and Frequency Offset Estimation Scheme for Orthogonal Frequency Division Multiplexing (OFDM) Systems”",
"by Bruce McNair, Leonard J. Cimini, Nelson Sollenberger, VTC99 May 1999.",
"BRIEF SUMMARY OF THE INVENTION 1.",
"Brief Summary of SCCS Since the SCCS system is using said very accurate FPD and said very accurate PS free of any uncontrolled phase transients, it can implement an inherently stable open loop configuration wherein a programmable control unit (PCU) provides signals producing totally predictable output clock phase implementing precisely defined phase transfer function between an external timing reference and the output clock.",
"In addition to elimination of said feedback related instability problems, such SCCS system allows ˜10 times better control of output clock phase transients and much lower phase jitter by synthesizing output phase with ˜10 times smaller and more accurate phase steps than conventional solutions.",
"The SCCS eliminates all four limitations mentioned in the “Background art”",
"section, by contributing improvements listed below: 1.",
"Since the SCCS uses an open-ended phase control system without any closed loop feedback, the SCCS enables inherently stable synthesis of the output clock, independently of reference frequency spectrum.",
"The SCCS defines digital frame phase detector (FPD), which eliminates said accumulation of digitization errors during phase tracking of highly irregular waveforms communicated with stamp messages of IEEE 1588 protocol.",
"The FPD part of the SCCS offers >5 times more accurate measurements of time errors, between the local clock and an external clock, occurring during variable lengths time intervals communicated by the external source.",
"The SCCS defines digital phase synthesizer (PS) enabling direct precise control of phase transfer function between PSs input and output clocks, and the PS allows ˜10 times lower jitter of output clock phase.",
"The SCCS significantly reduces system manufacturing costs, by enabling use of inexpensive lower frequency oscillators including all oscillators already used by potential customers, and by enabling use of inexpensive standard CMOS technologies for synthesizing high precision synchronization clocks.",
"The SCCS includes a Hybrid PLL (HPLL) which can multiply crystal frequencies as low as 30 kHz into a stable low jitter clock in GHz frequency range.",
"The HPLL comprises a DPLL driving an analog PLL (APLL) using an analog phase detector (APD) with return input connected to an APLL output clock and with reference input connected to said PS receiving the APLL output clock.",
"The DPLL minimizes digital phase error between said crystal oscillator clock and the APLL output clock, by introducing phase steps into a transfer function of said PS which produce appropriate phase errors on an output of said APD.",
"Since the DPLL is programmable;",
"it can convert any oscillator frequency into any local clock frequency, and consequently it allows use of local oscillator of any frequency including low frequency crystals and oscillators proven already in customers products.",
"Such HPLL solution is unique, as it allows: multiplication of said very low frequency clocks by factors which can be made as high as 50 000 without increasing jitter or causing stability problems, combined with indefinite flexibility and precision in setting frequency of generated high frequency clocks.",
"This major contributions over conventional solutions make the HPLL conclusively superior alternative to conventional PLLs in many major areas including analog, mixed mode SOC, signal processing, and all frequency control products where low jitter high multiplication is the major bottleneck.",
"In addition to the above mentioned advantages over conventional solutions;",
"the SCCS offers unique ability of precise recovering of every single edge of incoming noisy wave-form, with adaptive time-domain noise filtering edge detector (NFED).",
"The NFED densely over-samples incoming wave-form, and filters out phase noise from wave-form edges and eliminates amplitude glitches from wave-form pulses.",
"Still other advantage of SCCS is its ability to provide a single SOC design accepting all practically possible frequencies of timing references, as it is presented by a Heterodyne Timing Configuration of SCCS shown in FIG. 3 described in the next section.",
"In contrary to conventional solutions, the SCCS is not limited to discrete sets of input/output frequencies or local oscillator frequencies, but accepts a local oscillator (LocOsc) of any frequency and accepts an external reference clock (Ext_RefClk) of any frequency or an external reference waveform (Ext_RefWfm) carrying any reference frequency, while providing any required frequency of an SCCS output clock (OutClk).",
"Such very wide universality will allow synchronization products suppliers to replace wide variety of their SOC products with a single chip solution.",
"Consequently, their own costs will be significantly reduced and such single chip solution will make their product much more competitive as being easier to use across diversified product lines produced by major equipment manufacturers who are their major clients.",
"The next section SUMMARY OF THE INVENTION;",
"explains major configurations of the SCCS (see also FIG. 1 , FIG. 2 and FIG. 3 ), and justifying said configurations novel components such as the phase synthesizer, the frame phase detector and the noise filtering edge detector.",
"Brief Summary of Receiver Synchronization Techniques The RST alleviates said deficiencies of conventional solutions, since the RST comprises: supplementing or replacement of said conventional DSP techniques and processors unequipped to perform real-time processing of OFDM signal, with real-time synchronous processing techniques enabling very accurate detection of composite frame boundaries enabling time domain definition of said referencing frame maintaining predictable accurate timing relation to the OFDM signal received;",
"recovery of timing of composite frames boundaries, and using such timing to define said referencing frame;",
"using such referencing frame interval corresponding to any required plurality of OFDM symbols for estimating frequency offset, wherein estimation accuracy by one order higher than that of conventional solutions can be achieved (such accuracy improves proportionally to a length of referencing frame interval);",
"inherently stable frequency locked phase synthesis method (FLPS) for receiver frequency and phase control, wherein such highly accurate frequency offset estimates are used by a frequency locked loop for controlling frequency of its oscillator clock while time offset (phase error) estimates are applied only to a phase synthesizer utilizing such oscillator clock for synthesizing local symbol frame phase minimizing such time offset estimates (i.",
"e. phase aligned with the composite signal frame).",
"The RST comprises methods and systems for accurate and reliable recovery of said referencing frame from preambles or pilots commonly used already in OFDM systems, thus enabling substantially better receiver synchronization to OFDM composite signal frame.",
"Furthermore the RST comprises solutions enabling very accurate recovery of the referencing frame from data carrying tones only, and thus RST contributions over conventional solutions include;",
"10× lower frequency and time offset combined with improvement of system efficiency by eliminating preambles and pilots needed previously.",
"SUMMARY OF THE INVENTION 1.",
"Open Ended Configuration of Software Controlled Clock Synthesizer The open ended configuration of SCCS (OEC) is presented in FIG. 1 .",
"Such configuration comprises two major parts described below.",
"The first part is said Hybrid PLL (HPLL) for multiplying said local oscillator frequency provided by a crystal producing frequencies as low 30 kHz, by a programmed by PCU factor which can exceed 50 000 without any increase of jitter levels and without any stability problems.",
"The HPLL provides practically indefinite flexibility and precision in setting frequency of generated high frequency clocks.",
"Resulting frequency can rise as far as is it supported by a voltage controlled crystal oscillator (VCXO), as long as it remains lower than maximum clock frequency which exceeds GHz ranges in present IC technologies.",
"The HPLL comprises a DPLL (DPLL) driving an analog PLL (APLL) using an analog phase detector (APD) with return input connected to an APLL output clock (LocClk) and with reference input connected to a local phase synthesizer (LOC_PS) receiving the APLL output clock.",
"The DPLL minimizes digital phase error 2 (PhaErr2) between said local oscillator (LocOsc) and the LocClk, by introducing phase steps into an output phase of said LOC_PS which are converted by the APD into analog phase errors controlling phase locking between the LocClk and the OscClk.",
"The DPLL uses a frame phase detector 2 (FPD2) for measuring said PhaErr2 which is read by a programmable control unit (PCU) using it for producing said phase steps introduced into said LOC_PS output phase, wherein amount of introduced phase steps is controlled using an MC=1_INT signal received by the PCU from the LOC_PS.",
"The MC=1_INT signals a request from the LOC_PS demanding the PCU to send the next series of said phase steps when the last series is applied already.",
"The FPD2 receives PCU control signals programming expected relation between phase of the OutClk and phase of a sampling clock (SampClk) derived from the LocClk through a simple multiplication by a factor <8.",
"The second part is an open ended software controlled synthesizer (OE_SCS) using PCU software sub-routines for providing a programmable phase transfer function (PTF) between the Ext_RefWfm and the OutClk.",
"The OE_SCS offers;",
"unique ability to program very precisely synchronized phase free of any uncontrolled transients.",
"Therefore, the OE_SCS provides ˜10 times better precision in frequency and phase control than conventional solutions.",
"Furthermore, the OE_SCS offers inherently stable configuration independently of said highly unpredictable frequency spectrum of the time delay variations occurring in the Ext_RefWfm.",
"Consequently, the OE_SCS eliminates serious stability problems of conventional clock synchronizers bound to use closed loop configurations for implementing message-based protocols.",
"Said PCU controls operations of the OUT_PS by defining series of phase steps inserted by the OUT_PS into a phase of the OUTCLK.",
"The PCU calculates said phase steps by processing: a phase error 1 (PhaErr1) received form a frame phase detector 1 (FPD1) measuring phase error between the sampling clock and a filtered reference wave-form (Filt_RefWfm);",
"time stamp messages received from a Time Stamp Decoder (TSD) recovering such messages from the FILT_RefWfm produced by a noise filtering edge detector (NFED).",
"The PCU supplies the next series of said phase steps in response to the interrupt MC=1_INT from the OUT_PS which signals that insertions of the last series has been completed.",
"Furthermore the PCU controls operations of the NFED providing adaptive time domain filtering of the Ext_RefWfm carrying synchronization signals which can be encoded into time stamp messages or can be conventional BITS references.",
"The PCU receives unfiltered wave-form samples from the NFED and calculates most suitable noise filtering masks and algorithms which the PCU communicates back to the NFED (see Subsection 8.",
"Noise Filtering Edge Detector).",
"Compared to a moment when a sync message requesting capturing of a time stamp is received by the PCU;",
"an exact sync edge of the FILT_RefWfm destined to capture said time stamp can be displaced in time by a known number of message symbols (edge displacement).",
"Such edge displacement is determined by a messaging protocol used.",
"Since FPD1 keeps capturing time stamps of all received edges of the FILT_RefWfm, the FPD1 or the PCU shall be equipped with an edge selection circuit (ESC).",
"The ESC provides selection of time stamps captured by said sync edge and is synchronized by the time stamp messages produced by the Time Stamp Decoder.",
"Further definitions of a synchronization means provided by the OEC, such as Free-Run and Hold-Over modes, are provided in the Subsection 4.",
"Open Ended Configuration of SCCS with External Synchronization Mode The open-ended configuration of SCCS with external synchronization mode (OEC_ESM) is presented in FIG. 2 and is described below.",
"The OEC_ESM comprises the previously explained OEC and is further extended by adding an output clock analog PLL (OutClk_APLL).",
"The OutClk_APLL filters out jitter from a synthesized clock from the OUT_PS (SynOutClk) and produces SCCS output clocks (OutClk(T:1)) which are phase aligned with a reference clock selected by the PCU from a set of timing references including the SynOutClk, external reference clocks (Ext_RefClk) and a clock signal form a mate SCCS unit (f_mate).",
"Said external reference clocks are used in the external synchronization mode, wherein they are produced by a master synchronization unit and are used to synchronize multiple other units located in a back-plane of a network element.",
"However said other units can alternatively use other synchronization references available in other synchronization modes and may be synchronized by the Ext_RefWfm carrying a message based protocol or BITS clocks.",
"Such plurality of synchronization references and modes allows switching to one of alternative references when an active reference fails.",
"The f-mate clock from a mate unit allows Master/Slave protection switching which is described in the Subsection 4.",
"The output clock analog PLL comprises: a reference selector (RFS) connected to the SynOutClk from the OUT_PS and to the external reference clocks and to the f_mate clock and to the PCU, wherein the PCU controls selections of made by the RFS producing a reference clock (RefClk) for the OutClk_APLL;",
"a return clock divider (RCD) connected to a filtered output clock (Fil_OutClk) of the OutClk_APLL and to the PCU, wherein the PCU defines a division coefficient matching frequency of a return clock (RetClk) for the OutClk_APLL with a frequency of the RefClk;",
"an analog phase detector OutClk APD connected to the reference clock and to the return clock, and producing an analog phase error (PhaDet_UP/DN) driving an output clock loop filter (OutLoopFil) which drives a VCXO producing the filtered output clock;",
"an output PLL (OUT_PLL) for multiplying one selected OutClk(T:1) clock and for providing phase alignment between all the OutClk_APLL and the Fil_OutClk, wherein the OUT_PLL is connected to the selected OutClk(T:1) clock and to the Fil_OutClk;",
"an output clocks generator (OCG) connected to the output of the OUT_PLL and to the PCU, wherein the OCG produces the OutClk(T:1) which are phase aligned but have different frequencies wherein the PCU controls OCG operations by programming said frequencies of the SCCS output clocks.",
"Further definitions of synchronization means provided by the OEC_ESM, are provided in the Subsections 3 and 4.",
"Heterodyne Timing Configuration of SCCS The heterodyne timing configuration (HTC) simplifies SCCS by integrating: both the APLL and the OC APLL from the OEC_ESM, into a single APPL;",
"and both the REF PS and OUT_PS from the OEC_ESM, into a single RET_PS.",
"The two previous configurations of SCCS offer said practically unlimited universality in accepting said local oscillator (LocOsc) of any frequency and accepting said external reference waveform (Ext_RefWfm) carrying any reference frequency, while providing all practically needed frequencies of said SCCS output clocks (OutClk(T:1)).",
"The HTC extends this universality even further by enabling acceptance of practically unlimited ranges of said external reference clocks (Ext_RefClk) as well.",
"Therefore despite implementing a close loop system, the HTC may still be used as a less costly alternative;",
"if timing reference is not provided by a message based protocol, or if a message-based protocol is used in simple networks with stable TDVs.",
"Said integration is achieved by placing a return phase synthesizer (RET_PS) into a return path of the integrated APLL.",
"Consequently said phase steps supplied by the PCU need to be reversed as they are subtracted from a phase of a reference clock of the APLL instead of being added to it.",
"Indefinite RET_PS flexibility in phase and frequency generation makes it much better frequency divider than the previous configuration Return Clock Divider and allows said unlimited flexibility in accepting all frequencies of the Ext_RefClk.",
"Resulting HTC comprises: a programmable control unit (PCU) for implementing a programmable phase transfer function (PTF) between the OutClk and the Ext_RefClk or the Ext_RefWfm, wherein the PCU controls operations of the return phase synthesizer (RET_PS), the PCU has a terminals for an interrupt MC=1_INT and for a first phase error (PhaErr1) and for a second phase error (PhaErr1) and for a time stamp message and for a waveform sample;",
"the reference selector (RFS) connected to a filtered local clock (Fil_OutClk) and to the external reference clocks (Ext_RefClk) and to the f_mate clock and to the PCU, wherein the PCU defines selections made by the RFS producing a reference clock (RefClk) for the analog phase detector (APD);",
"the RET_PS connected to a filtered output clock (Fil_OutClk) and connected to the PCU wherein the RET_PS requests PCU to supply the next series of phase steps by activating the MC=1_INT, wherein the RET_PS introduces such phase steps into the Fil_OutClk thus synthesizing a return clock (RetClk) for the APD;",
"the APD connected to the RefClk and to the RetClk, the APD producing an analog phase error (PhaDet_UP/DN) driving an output clock loop filter (OutLoopFil) which drives a VCXO producing the filtered output clock;",
"the output PLL (OUT_PLL) for multiplying one selected OutClk(T:1) clock and for providing phase alignment between all the OutClk_APLL and the Fil_OutClk wherein the OUT_PLL is connected to the selected OutClk(T:1) clock and to the Fil_OutClk, wherein the OUT_PLL produces an output reference clock (OutRef) connected to the OCG and to the FPD2;",
"the output clocks generator (OCG) connected to the output of the OUT_PLL and to the PCU, wherein the OCG produces the OutClk(T:1) which are phase aligned but have different frequencies wherein the PCU controls OCG operations by programming said frequencies of the SCCS output clocks;",
"the NFED and the TSD and the FPD1 and the FPD2 having the same connectivity and performing the same operations as defined in the Subsection 1, with the exception of the FPD2 which is connected to the OutRef and to the LocOsc and to the PCU;",
"wherein the PCU uses its internal micro-operations for implementing filter functions of an on chip digital PLL (DPLL) by processing the PhaErr1 and the PhaErr2 and the time stamp messages into the PCU output driving the RET_PS into producing the synthesized return clock providing compliance of the SCCS output clocks with the phase transfer function defined by the PTF, wherein the PCU controls NFED operations as it is described in the Subsection 1.",
"SCCS Configurations In contrary to conventional frequency synthesizers, SCCS phase synthesizer produces totally predictable phase and frequency responses to received from the PCU control signals.",
"Therefore it enables said open ended configurations which can work with only one frame phase detector (FPD) for measuring phase errors between a timing reference and a local clock, in order to implement an actual synchronization system.",
"The second FPD in the open ended configuration explained in the Subsection 1, is used for the frequency multiplication of said local oscillator only.",
"If a local clock had sufficiently high frequency, the FPD would not be needed at all.",
"As said conventional frequency synthesizers produce unpredictable transient during frequency switching, they require second digital phase detector for providing feedback about a phase of synthesizers output clock in order to reduce said phase transients with a DPLL.",
"An open ended configuration without said multiplication of LocOsc frequency is defined below.",
"A Software Controlled Clock Synthesizer (SCCS) for implementing a programmable phase transfer function (PTF) between an SCCS output clock (OutClk) and external reference clocks (Ext_RefClk) or an external reference carrying wave-form (Ext_RefWfm) such as BITS references or line references or time stamp messages;",
"the SCCS comprises: a programmable control unit (PCU) using software subroutines for controlling SCCS status and for said implementation of the PTF, wherein the PCU controls operations of a return clock phase synthesizer (RET_PS), the PCU has terminals for interrupts from other SCCS circuits and for a first phase error (PhaErr1) and for a second phase error (PhaErr2) and for a time stamp message and a for a waveform sample;",
"the RET_PS for synthesizing a return clock (RetClk), the RET_PS connected to the PCU and to the SCCS output clock (OutClk);",
"the APLL for producing the OutClk, wherein a reference input of the APLL is connected to the OutClk or to the Ext_RefClk while the return input of the APLL is connected to the synthesized RetClk;",
"a first frame phase detector (FPD1) receiving a local reference clock (LocClk) and the Ext_RefWfm or receiving the LocClk and the OutClk or receiving the Ext_RefClk and the OutClk, wherein the FPD1 produces the PhaErr1 connected back to the PCU;",
"wherein said PCU uses said software subroutines for implementing a digital PLL (DPLL) by processing said first phase error and the second phase error into the PCU output driving the RET_PS into synthesizing the RetClk providing compliance of the APLL output clock with the phase transfer function defined by the PTF.",
"The SCCS includes reference selection means for alternative use of one of multiple connected external timing references, such as reference clocks or external waveforms, for producing the SCCS output clock, the SCCS further comprises: a reference selector connected to multiple external timing references and controlled by the PCU, wherein the PCU selects one of the multiple timing references for being connected to the FPD1 which is read by the PCU and used by PCU subroutines for controlling the SCCS output clock;",
"activity monitors for the external timing references for producing status signals indicating active/non-active conditions, wherein said status signals are connected to the PCU;",
"wherein the output signals of the activity monitors are read and processed by the microprocessor which is producing reference selection signals connected to the reference selectors.",
"The SCCS further comprises: an output phase locked loop (OUT-PLL) referenced by the APLL output clock and producing a fundamental output clock, wherein the OUT-PLL has a return input connected to one SCCS output clock;",
"an output clock generator (OCG) connected to the fundamental output clock, the OCG produces a plurality of the SCCS output clocks (OutClk).",
"The SCCS further comprises: interface circuits, for communication with an external control processor, connected to the external control processor and to the PCU (see the Parallel Interface and the Serial Interface in the FIG. 1 and FIG. 2 and FIG. 3 );",
"wherein the interface circuits and the PCU enable the external control processor to read information about statuses of the activity monitors and to select an external reference clock or the local reference clock for referencing the SCCS output clock.",
"Furthermore in the interface circuits and the PCU enable the external control processor to perform switching of mode of operation of the SCCS between the APLL mode and the DPLL mode.",
"The SCCS PCU is provisioned to perform operations listed below: reading information about statuses of the activity monitors and selecting an external timing reference or the local reference clock for referencing the SCCS output clock;",
"switching mode of operation of the SCCS between the APLL mode and the DPLL mode.",
"Furthermore the SCCS is provisioned to perform a master/slave mode switching for maintaining phase alignment between an active SCCS unit and a backup SCCS unit installed in a back-plane for protection switching, the SCCS comprises: a master/slave subroutine reading activity monitor of a reference clock provided by a mate SCCS unit and reading internal status of the own SCCS unit;",
"wherein the master/slave subroutine performs switching to the master mode by selecting other reference clock than the mate's reference clock when the mate's reference clock becomes inactive or performs switching to the slave mode by selecting the mate's reference clock when the mate's reference clock is detected active during a power-up initialization of the own SCCS unit.",
"The SCCS comprises using a programmable phase synthesizer to produce an Analog PLL return clock, which can be reprogrammed to match a frequency of a reference clock of said Analog PLL.",
"Furthermore the SCCS comprises: applying an output clock of the APLL to a reference input of the APLL;",
"using the return clock synthesizer for inserting phase deviations between the APLL return clock and the output clock applied to the APLL reference input;",
"using the inserted phase deviations for implementing required phase and frequency transfer functions between the APLL output clock and other SCCS reference clocks;",
"implementing digital PLL (DPLL) algorithms for providing the required phase and frequency transfer functions.",
"Still furthermore the SCCS comprises: using frame phase detectors (FPDs) for measuring phase errors between the APLL output clock and said other SCCS reference clocks;",
"using the PCU for processing the measured phase errors and producing control codes for the return clock synthesizer, which implement pre-programmed phase and frequency transfer functions between the APLL output clock and said other SCCS reference clocks.",
"The SCCS comprises: Said analog phase locked loop (APLL) for producing the output clock (OutClk) which can be locked to the external reference clock (Ext_RefClk), unless the APLL is driven by the digital phase locked loop (DPLL);",
"Said DPLL can provide locking to the Ext_RefWfm (which can be a GPS clock).",
", or to a local oscillator.",
"The SCCS further comprises: programmable frequency dividers for a reference signal and for return signal of said APLL, for providing programmable bandwidth adjustments of the APLL;",
"programmable frequency dividers in the output clock generator (OCG) which can be reprogrammed by the PCU, in order to allow utilizing a single pin of the OutClk(T:1) for providing multiple different output clock frequencies;",
"activity monitoring circuits for synchronizer input clocks and output clocks;",
"frequency monitoring circuits for synchronizer reference clocks;",
"status control circuits for switching synchronizer modes of operation and active reference clocks, based on an analysis of said activity and frequency monitoring circuits;",
"phase transfer control circuits for providing a required phase transfer function between an active reference clock and synchronizer output clocks;",
"a serial interface which allows the status control circuits and the phase transfer control circuits to be monitored and reprogrammed by an external controller (see the Serial Interface in the FIG. 1 , FIG. 2 and FIG. 3 );",
"a parallel interface which allows the status control circuits and the phase transfer control circuits to be monitored and reprogrammed by an external controller controller (see the Prallel Interface in the FIG. 1 , FIG. 2 and FIG. 3 );",
"automatic reference switching functions including hold-over and free-run switching, which are performed by the status control circuits and are based on monitoring a status of the activity and frequency monitoring circuits;",
"a master/slave switching circuit which allows a pair of integrated synchronizers to work in a master/slave configuration having a slave synchronizer being phase locked to a mate clock which is generated by a mate master synchronizer;",
"The above listed status control circuits and phase transfer control circuits can be implemented as separate on-chip control units or with a single on-chip PCU.",
"APLL mode of operation in the Heterodyne Timing Configuration is described below.",
"One of the external reference clocks (Ext_RefClk) is selected to be applied to the APLL reference input and the return phase synthesizer (RET_PS) is switched by the PCU into producing the APLL return clock which is matching said selected external reference clock.",
"The implementation of a DPLL mode is explained below.",
"The APLL output clock Fil_OutClk is applied to the APLL reference input and the return phase synthesizer (RET_PS) is switched by the PCU into producing the APLL return clock which is matching said output clock Fil_OutClk.",
"The FPD1 measures a phase error between the output clock multiplication SampClk and the Ext_RefWfm, and the FPD2 measures a phase error between the SampClk and the local oscillator LocOsc.",
"The PCU reads the above phase errors and uses them to calculate new contents of the RET_PS's periodical adjustment buffers and the fractional adjustment buffers needed for inserting phase deviations required for providing a phase transfer function (PTF), between the output clock Fil_OutClk and the Ext_RefWfm, which is already preprogrammed in the PCU.",
"The invention includes providing slave mode implementation which replaces the external reference clock with the mate SCCS output clock f_mate, in order to drive the above described APLL configuration.",
"The slave mode allows maintaining phase alignment between active and reserve SCCS units, for the purpose of avoiding phase hits when protection switching reverts to using clocks from the reserve SCCS unit.",
"The invention includes using the above mentioned method of slave SCCS phase alignment for all 3 configurations shown in the FIG. 1 , FIG. 2 and FIG. 3 ).",
"Digital Wave Synthesis from Multi Sub-Clocks The invention comprises the digital wave synthesis from multi-sub-clocks (DWS MSC) as a new timing method and circuit for programming and selecting a phase and a frequency of a synthesized clock.",
"The DWS MSC comprises programmable phase modifications which are defined below: Phase increases of the synthesized clock are provided;",
"by adding whole clock periods and/or fractional sub-clock delays, obtained from serially connected delay elements which the reference clock is propagated through, to a present phase obtained from a counter of reference clock periods and/or a present fractional sub-clock delay.",
"Phase decreases of the synthesized clock are provided;",
"by subtracting whole clock periods and/or fractional sub-clock delays, obtained from serially connected delay elements which the reference clock is propagated through, from a present phase obtained from a counter of clock periods and/or a present fractional sub-clock delay.",
"The DWS MSC provides ˜10 times better phase adjustment resolution than the commonly used DDFS method;",
"because the DWS MSC can modify phase with time intervals specified in fractions of clock cycle, instead of inserting or eliminating whole clock cycles from a synthesized clock.",
"Therefore, the phase hits and resulting jitter are reduced by around 10 times compared to the DDFS method.",
"The DWS MSC provides an implementation of programmable algorithms for synthesizing a very wide range of low and high frequency wave-forms.",
"The DWS MSC comprises;",
"a 1-P phase generator, a synchronous sequential phase processor (SSPP) for real time processing and selection of a phase of out-coming wave-form, and a programmable computing unit (PCU) for controlling SSPP operations and supporting signal synthesis algorithms.",
"Said 1-P phase generator is an extension of a 1bit odd/even phase generator to p bits enabling 2 p =P phases to be generated from every reference sub-clock, as it is defined below.",
"The odd/even phase generator provides splitting of reference sub-clocks, generated by outputs of a reference propagation circuit built with serially connected gates which a reference clock is propagated through, into odd phase sub-clocks which begin during odd cycles of the reference clock and even phase sub-clocks which begin during odd cycles of the reference clock, wherein the odd/even phase selector comprises: said reference propagation circuit connected to the reference clock;",
"serially connected flip-flops, wherein a clock input of a first flip-flop is connected to the reference clock and a data input of a first flip-flop is connected to an inverted output of the first flip-flop while a clock input of any other Nth flip-flop is connected to an (N−1) output of the reference propagation circuit and a data input of the N flip-flop is connected to an output of the (N−1) flip-flop;",
"connected to the serially connected flip-flops an odd/even selector generating the odd sub-clocks which begin during every odd reference clock cycle and the even sub-clocks which begin during every even reference clock cycle, wherein the output of the 1 st flip-flop is used to select odd and even reference clocks while the output of the Nth flip-flop is used to select odd and even reference sub-clocks from the (N−1) output of the reference propagation circuit.",
"The odd/even phase generator is extended into the 1-P phase generator splitting the reference sub-clocks into 1-P phase sub-clocks which begin during the corresponding 1-P cycles of the reference clock, wherein the 1-P phase selector further comprises: a parallel 1-P sub-clock counter built as an extension to the first flip-flop working as 1-2 counter wherein the whole 1-P sub-clock counter is clocked by the first reference sub-clock, wherein an output of the 1-P sub-clock counter represents a 1-P phase number of the first sub-clock;",
"2-N parallel multi-bit buffers built as extensions to the original 2-N flip-flops working as 1 bit buffers wherein the whole 1-P sub-clock counter is clocked by the 2 nd reference sub-clock into the first multi-bit buffer which is clocked by the 3 rd reference sub-clock into the 2 nd multi-bit buffer and the content of the 1-P counter is similarly propagated into all next buffers until the Nth sub-clock loads the N−2 buffer into the N−1 buffer, wherein the 1 st buffer defines a phase number minus 1 for the 2 nd reference sub-clock and next buffers define similarly phase numbers for their corresponding reference sub-clocks until the N−1 buffer defines a phase number minus (N−1) for the Nth reference sub-clock.",
"1-P phase selectors built as extensions to the corresponding odd/even selectors wherein a first 1-P selector is connected to the 1-P sub-clock counter and selects a phase, of the first reference sub-clock, defined by the 1-P sub-clock counter while every next N−K+1 phase selector is connected to its N−K buffer and to its N−K+1 reference sub-clock (0<K<N), wherein every next N−K+1 phase selector generates phases, of its N−K+1 sub-clock, defined by its buffer content plus (N−K).",
"The 1-P phase generator can use both solutions defined below: using rising edges of the reference sub-clocks for clocking the 1-P sub-clock counter and the 2-P buffers while negative pulses of the reference sub-clocks are used for activating outputs of the 1-P selectors generating the 1-P phase sub-clocks;",
"or using rising edges of the reference sub-clocks for clocking the 1-P sub-clock counter and the 2-P buffers while negative pulses of the reference sub-clocks are used for activating outputs of the 1-P selectors generating the 1-P phase sub-clocks.",
"Furthermore the 1-P phase generator can use the serially connected gates of the reference propagation circuit, which are connected into a ring oscillator controlled by a PLL circuit or are connected into a delay line control by a delay locked loop (DLL) circuit or are connected into an open ended delay line.",
"Furthermore this 1-P phase generator includes extending the remaining 2-N flip-flops with parallel sub-clock counters, the same as the parallel sub-clock counter extending the 1st flip-flop, instead of using the defined above 2-P multi-bit buffers.",
"The use of the 2-P parallel counters requires adding preset means for all the 1-P counters, in order to maintain the same or predictably shifted content in all the 1-N parallel counters.",
"Continues maintaining of said predictability of all the parallel counters content is necessary for generating predictable sequences of multiphase sub-clocks.",
"Said SSPP comprises a selection of one of multi sub-clocks for providing an edge of out-coming synthesized signal, where said sub-clocks are generated by the outputs of serially connected gates which an SSPP reference clock is propagated through.",
"The SSPP comprises calculating a binary positioning of a next edge of the out-coming wave-form versus a previous wave edge, which represents a number of reference clock cycles combined with a number of reference clock fractional delays which correspond to a particular sub-clock phase delay versus the reference clock.",
"Furthermore the SSPP comprises selective enabling of a particular sub-clock, which provides the calculated phase step between the previous and the current wave-form edges.",
"The SSPP further comprises a synchronous sequential processing (SSP) of incoming signal by using multiple serially connected processing stages with every stage being fed by data from the previous stage which are clocked-in by a clock which is synchronous with the reference clock.",
"Since every consecutive stage is driven by a clock which is synchronous to the same reference clock, all the stages are driven by clocks which are mutually synchronous but may have some constant phase displacements versus each other.",
"The synchronous sequential processor (SSP) multiplies processing speed by splitting complex signal processing operation into a sequence of singular micro-cycles, wherein: every consecutive micro-cycle of the complex operation is performed by a separate logical or arithmetical processing stage during a corresponding consecutive time slot synchronous with a reference clock providing a fundamental timing for a synthesized wave-form;",
"serially connected sequential stages are connected to a programmable control unit (PCU), wherein the sequential stages are clocked by reference sub-clocks generated by a reference propagation circuit built with serially connected gates which the reference clock is propagated through;",
"whereby inputs from the PCU are processed into a phase delay between a next edge of the synthesized wave-form versus a previous edge and a position of the next edge is calculated by adding the phase delay to a position of the previous edge, wherein the positions of wave-form edges are provided by a last of the sequential stages and said positions are expressed as numbers identifying reference sub-clocks needed for generating said wave-form edges.",
"The above defined SSP can be implemented by processing said inputs from the PCU into a phase modification step which is added to a period of the reference clock in order to calculate the phase delay.",
"Furthermore this invention includes the SSP circuit upgraded into a parallel multiphase processor (PMP) by extending the time slot allowed for the micro-cycles of the synchronous sequential processor by a factor of P, wherein: 2-P stages are added to the original sequential stage and every one of the resulting 1-P parallel multiphase stages is clocked with a corresponding 1-P phase sub-clock, wherein such 1-P phase sub-clock begins during the corresponding to that phase 1-P cycle of the reference clock and has a cycle which is P times longer than the reference clock cycle;",
"whereby consecutive 1-P parallel multiphase stages have processing cycles overlapping by 1 cycle of the reference clock wherein every 1-P parallel processing stage has P times longer cycle time equal to the cycle time of the corresponding 1-P phase sub-clock used for timing that stage.",
"The parallel multiphase processor further comprises: a parallel processing phase 2-P built with plurality of 2-P parallel multiphase stages which are connected serially and are driven by the phase sub-clocks belonging to the same 2-P phase.",
"The SSPP invention comprises the use of the parallel multiphase processing for synthesizing a target wave-form by assigning consecutive parallel phases for the processing of a synthesized signal phase using signal modulation data provided by a programmable control unit (PCU) or by any other source.",
"Consequently the SSPP comprises using 1 to N parallel phases which are assigned for processing incoming signal data with clocks corresponding to-reference clock periods number 1 to N, as it is further described below: circuits of phase1 process edge skews or phase skews or other incoming signal data with a clock which corresponds to the reference clock period number 1;",
"circuits of phase2 process edge skews or phase skews or other incoming signal data with a clock which corresponds to the reference clock period number 2;",
"finally circuits of phaseN process edge skews or phase skews or other incoming signal data with a clock which corresponds to the reference clock period number N. Said parallel multiphase processing allows N times longer processing and/or sub-clocks selection times for said multiphase stages, compared with a single phase solution.",
"The above mentioned sub-clock selecting methods further include: using falling edges of said sub-clocks for driving clock selectors which select parallel processing phases during which positive sub-clocks are enabled to perform said synthesized wave-form timing, or using rising edges of said sub-clocks for driving selectors which select parallel processing phases during which negative sub-clocks are enabled to perform said synthesized wave-form timing;",
"using serially connected clock selectors for enabling consecutive sub-clocks during said processing phases, in order to assure that the enabled sub-clocks will occur within a selected processing phase and to enable selection of a sub-clock specified by a number contained in a fraction selection register of a particular processing phase.",
"The SSPP includes using said serially connected gates: as being an open ended delay line;",
"or being connected into a ring oscillator which can be controlled in a PLL configuration;",
"or being connected into a delay line which can be controlled in a delay locked loop (DLL) configuration.",
"Every said sub-clock phase delay versus the reference clock phase amounts to a fraction of a reference clock period which is defined by a content of a fraction selection register which is assigned for a particular processing phase and is driven by the SSPP.",
"The SSPP includes a parallel stage processing of an incoming signal by providing multiple processing stages which are driven by the same clock which is applied simultaneously to inputs of output registers of all the parallel stages.",
"The SSPP further comprises: a merging of processing phases which occurs if multiple parallel processing phases are merged into a smaller number of parallel phases or into a single processing phase, when passing from a one processing stage to a next processing stage;",
"a splitting of processing phases which occurs if one processing phase is split into multiple processing phases or multiple processing stages are split into even more processing stages, when passing from a one processing stage to a next processing stage.",
"The SSPP includes using the 1-P phase generator defined above to generate SSPP clocks which drive said parallel phases and said sequential stages, and to generate selector switching signals for said merging and splitting of processing phases.",
"The SSPP includes time sharing of said parallel phases: which is based on assigning a task of processing of a next wave-form edge timing to a next available parallel processing phase.",
"The SSPP comprises a timing control (TC) circuit, which uses decoding of reference clock counters and/or other wave edge decoding and said SSPP clocks, for performing said time sharing phase assignments and for further control of operations of an already assigned phase.",
"The SSPP comprises passing outputs of a one parallel phase to a next parallel phase, in order to use said passed outputs for processing conducted by a following stage of the next parallel phase.",
"The outputs passing is performed: by re-timing output register bits of the one phase by clocking them into an output register of the next parallel phase simultaneously with processing results of the next parallel phase.",
"The SSPP further comprises all the possible combinations of the above defined: parallel multiphase processing, parallel stage processing, synchronous sequential processing, merging of processing phases, splitting of processing phases, and outputs passing.",
"The SSPP includes processing stage configurations using selectors, arithmometers, and output registers, which are arranged as it is defined below: input selectors select constant values or outputs of previous stages or outputs of parallel stages or an output of the same stage to provide arithmometer inputs, and arithmometer output is clocked-in to an output register by a clock which is synchronous to the reference clock;",
"multiple arithmometers are fed with constant values or outputs of previous stages or outputs of parallel stages or an output of the same stage, and an output selector selects an arithmometer output to be clocked-in to an output register by a clock synchronous to the reference clock;",
"the above defined configuration as being supplemented by using an output of an output selector of a parallel processing stage for controlling functions of other output selector.",
"The SSPP comprises: using switching signals of said input selectors for producing pulses which clock data into output registers of previous stages;",
"using switching signals of said output selectors for producing pulses which clock data into output registers of previous stages;",
"The SSPP also comprises: using results obtained in earlier stages for controlling later stages operations, and using results obtained in the later stages for controlling the earlier stages operations.",
"Proper arrangements of said parallel and sequential combinations and said stages configurations provide real time processing capabilities for very wide ranges of signal frequencies and enable a wide coverage of very diversified application areas.",
"The DWS MSC comprises two different methods for accommodating a phase skew between the reference clock and a required carrier clock frequency of the transmitted signal, and both methods allow elimination of ambiguities and errors in encoding of output signal data patterns.",
"Said two methods are further defined below: a source of the reference clock provides frequency or phase alignment with the timing of the data which are being encoded and sent out in the synthesized output wave-form;",
"phase skews between the reference clock and the timing of the destined for transmission data are digitally measured and translated into implemented by the SSPP phase adjustments of the synthesized signal which provide required carrier frequency of the transmitted output signal;",
"both above mentioned methods include measurements of phase or frequency deviations of the destined for transmission data versus the reference clock, and using said measurements results to assure required carrier frequency of the synthesized signal.",
"Furthermore the DWS MSC method comprises phase modulations of the synthesized wave-form by adding or subtracting a number of reference clock periods and/or a number of fractional delays to a phase of any edge of the synthesized wave-form.",
"Said adding or subtracting of a number of reference clock periods is further referred to as a periodical adjustment, and said adding or subtracting of fractional delays is further called a fractional adjustment.",
"The DWS MSC method allows synthesizing of any waveform by modulating a phase of the reference clock with periodical and/or fractional adjustments of any size.",
"6 Phase Synthesizer The invention also includes the Phase Synthesizer (PS) for carrying out the DWS MSC method;",
"as it is further explained below and is shown in FIG. 4 , FIG. 4A , FIG. 5 , and FIG. 6 .",
"The Timing Diagram of the PS is shown in the FIG. 7 .",
"Said phase synthesizer provides programmable modifications of a phase of a synthesized clock by unlimited number of gate delays per a modification step with step resolution matching single gate delay at steps frequencies ranging from 0 to ½ of maximum clock frequency, wherein: a delay control circuit is connected to a programmable control unit (PCU) wherein the delay control circuit defines size and frequency of phase delay modifications of the synthesized clock versus a reference clock, the delay control circuit also having a terminal connected to reference sub-clocks generated by a reference propagation circuit or connected to odd/even sub-clocks generated by an odd/even phase selector;",
"the reference clock is connected to the reference propagation circuit consisting of serially connected gates wherein outputs of the gates generate the reference sub-clocks providing variety of phase delays versus the reference clock;",
"the reference sub-clocks are connected to an odd/even phase selector which splits the reference sub-clocks by generating separate odd sub-clocks and even sub-clocks, wherein the odd sub-clocks begin during odd cycles of the reference clock and the even sub-clocks begin during even cycles of the reference clock;",
"a clock selection register is loaded by the odd sub-clocks and by the even sub-clocks with the outputs of the delay control circuit, wherein the odd sub-clocks or the even sub-clocks beginning during an earlier cycle of the reference clock download outputs of the delay control circuit which select the even sub-clocks or the odd sub-clocks beginning during a later cycle of the reference clock for providing the synthesized clock;",
"an output selector is connected to the output of the clock selection register and to the outputs of the odd/even phase selector, wherein the output selector uses inputs from the clock selection register for selecting output of the odd/even phase selector which is passed through the output selector for providing the synthesized clock.",
"The above defined PS can use the odd/even phase generator or the 1-P phase generator, which have been already defined above.",
"The PS can use the delay control circuit implemented with the parallel multiphase processor (PMP) which has been already defined above.",
"The PS comprises 2 different implementation methods, which are explained below.",
"The first PS implementation method is based on moving a synthesized clock selection point from a delay line which propagates a reference clock (see the FIG. 4 );",
"wherein: said phase increases are provided by moving said selection point of the synthesized clock from the reference clock propagation circuit, in a way which adds gate delays to a present delay obtained from the propagation circuit;",
"said phase decreases are provided by moving said selection point of the synthesized clock from the reference clock propagation circuit, in a way which subtracts gate delays from a present delay obtained from the propagation circuit;",
"The first PS implementation method is conceptually presented in FIG. 4 &",
"FIG. 6 , and its principles of operations are explained below.",
"The PLL×L Freq.",
"Multiplier produces the series of sub-clocks Clk0, ClkR-Clk1.",
"The sub-clock Clk0 keeps clocking in a reversed output of its own selector PR0.",
"The sub-clocks CLkR-Clk1 keep clocking in outputs of the previous selectors PR0, PRR-PR2 into their own selectors PRR-PR1.",
"Since the selector PR0 is being reversed by every Clk0, every selector in the PR0, PRR-PR1 chain is being reversed as well by a falling edge of its own sub-clock Clk0, ClkR-Clk1, and every selector in the chain represents reversal of its predecessor which is delayed by a single sub-clock fractional delay.",
"Consequently the PR0, PR1N-PRR select sub-clocks Clk0, Clk1-ClkR during any odd processing phase, and their reversals PR0N, PR1-PRRN select sub-clocks Clk0, Clk1-ClkR during any even processing phase.",
"The odd/even processing phase has been named phase1/phase2, and their sub-clocks are named 1Clk0, 1Clk1-1ClkR/2Clk0, 2Clk1-2ClkR accordingly.",
"Since said phase1/phase2 sub-clocks are used to run a phase synthesis processing in separate designated for phase1/phase2 phase processing stages which work in parallel, a time available for performing single stage operations is doubled (see also the FIG. 6 for more comprehensive presentation of said parallel processing).",
"Furthermore, the Clock Selection Register 1 (CSR1) can be reloaded at the beginning of the phase2 by the 2Clk0 and its decoders shall be ready to select a glitch free phase1 sub-clock which is defined by any binary content of the CSR1.",
"Similarly the CSR2 is reloaded by the 1Clk0, in order to select a single glitch free sub-clock belonging to the phase2.",
"The second PS implementation method is based on adjusting alignment between an exit point of the synthesized clock from the reference propagation circuit versus an input reference clock;",
"in a way which adds gate delays for phase increases, and subtracts gate delays for phase decreases.",
"The second method is presented in FIG. 4A , and its differences versus the FIG. 4 are explained below.",
"The moving exit point from the driven by Fsync/2Dsel phase locked delay line is used as a return clock for the PLL×2Dsel multiplier, instead of using a fixed output of the INV0 to be the PLL return clock.",
"The fixed output of the INV0 is divided by the programmable frequency divider (PFD) in order to provide the synthesized clock Fsynt, instead of the moving synthesized clock selection point.",
"The first method exit point alignments, introduce phase jumps which cause synthesized clock jitter.",
"The second method configuration shown in FIG. 4A , filters out Fsynt jitter frequencies which are higher than a bandwidth of the multiplier's PLL.",
"While any of the two PS implementation methods is shown above using a particular type of a reference clock propagation circuit, the PS comprises using all the listed below reference clock propagation circuits by any of the two methods: an open ended delay line built with serially connected logical gates or other delay elements;",
"a ring oscillator built with serially connected logical gates or other delay elements, which have propagation delays controlled in a PLL configuration;",
"a delay line built with serially connected logical gates or other delay elements, which have propagation delays controlled in a Delay Locked Loop (DLL) configuration.",
"It shall be noticed that further splitting to more than 2 parallel phases is actually easier than the splitting to the original 2 processing phases;",
"because while one of the phases is active, its earlier sub-clocks can be used to trigger flip-flops which can segregate sub-clocks which belong to multiple other phases and can be used to drive the other parallel phases.",
"Consequently using this approach;",
"allows increasing parallel stages processing times to multiples of reference clock periods, and provides implementation of said DWS MSC multiple phase processing which has been introduced in the previous section.",
"Said selection of a sub-clock for synthesized clock timing, can be physically implemented in two different ways: by using phase producing gates from linv0 to linvR and from linv0 to linvR, as having 3state outputs with enable inputs EN, one of which is enabled by one of the outputs of the sub-clock selection gates from 1sel0 to 1selR and from 2sel0 to 2selR;",
"or by using the sub-clock selection gates which have all their outputs connected into a common collector configuration (instead of having them followed by the 3 state gates), in order to allow a currently active output of one of the sub-clock selection gates to produce a phase of the synthesized clock FselN.",
"The PS comprises fractional adjustments of synthesized clock phase for providing high resolution phase modifications by fractional parts of a reference clock period.",
"The PS comprises combined periodical and fractional adjustments of synthesized clock phase, which use counters of reference clock periods for generating counter end (CE) signals when a periodical part of a phase adjustment is expired.",
"The PS further comprises using said counter end signals for generation of control signals which assign and/or synchronize consecutive parallel processing phases for processing consecutive combined or fractional phase adjustments of the synthesized clock.",
"The PS comprises: Using a basic periodical adjustment and a basic fractional adjustment for providing a basic phase step, which can remain the same for multiple edges of the synthesized clock.",
"Using a modulating periodical adjustment and a modulating fractional adjustment, which can be different for every specific edge of the synthesized clock.",
"Using said DWS MSC and SSPP methods for processing of said basic periodical adjustments, basic fractional adjustments, modulating periodical adjustments and modulating fractional adjustments for calculating periodical and fractional parts of combined adjustments.",
"Processing of said calculated combined adjustment with a positioning of a synthesized clock previous edge for calculating a periodical and a fractional part of the next edge position of the synthesized clock.",
"Frame Phase Detector The Frame Phase Detector (FPD) operates as follows: local clock phase is measured continuously by counting time units signaled by the local clock;",
"abstract frame, consisting of time intervals defined by software, is used for high resolution measurements of local clock phase error versus an external clock phase defined by it's frame signaled by external events, wherein such time intervals expected by software and expressed in local time units are subtracted from time intervals, occurring between said external events, measured in local clock units;",
"resulting phase error is read back by software subroutines.",
"Using such software defined frame instead of using an equivalent frame produced by hardware is advantageous, as it eliminates circuits and errors associated with using such electrical local frame and allows instant phase adjustments to be applied after the arrival of the external frame thus resulting in more stable DPLL operations.",
"Furthermore such software frame is more suitable for time messaging protocols such as IEEE 1588.",
"Subtracting a nominal number of local clock cycles corresponding to an imaginary frame has been anticipated by Bogdan in U.S. Pat. No. 6,864,672 wherein basic circuits and timing diagrams are shown, however this invention comprises further contributions, such as: more comprehensive programming of said software frame, in order to allow timing adjustments in more complex systems with rapidly changing references frequencies and references phase hits;",
"programmable presetting of numerical first edge allows elimination of an initial phase error when phase error measurements begun, in order to enable the use of the FPD for very precise delay measurements in critical traffic control applications;",
"elimination of any accumulation of digitization errors with an alternative solution simpler than presently existing arrangement.",
"The FPD comprises solutions described below.",
"A frame phase detector (FPD) for measuring a frame phase skew between a first frame consisting of a programmable sequence of expected numbers of sampling local clocks, and a second frame defined with a series of time intervals located between second frame edges defined by changes of an external frame signal or by changes of a frame status signal driven with external messages such as time stamps, wherein a frame measurement circuit captures a number of said sampling clocks occurring during an interval of the second frame and a phase processing unit subtracts the captured number from the expected number representing expected duration of the corresponding interval of the first frame;",
"wherein-the frame phase detector comprises: a means for a detection of said second frame edges, by detecting said changes of the external frame signal, or by detecting said changes of the frame status driven by the external messages;",
"the frame measurement circuit using the sampling local clock, which is a higher frequency signal, to measure said time intervals of the second frame having lower frequency, wherein the frame measurement circuit counts said sampling clocks occurring during every interval of the second frame and captures and buffers the counted value until it is read by a phase processing unit;",
"the phase processing unit for subtracting the expected number of the sampling clocks from the counted number of the sampling clocks, in order to calculate an interval phase skew between the expected interval of the first frame and the corresponding interval of the second frame.",
"a means for combining said interval phase skews of particular frame intervals into said frame phase skew.",
"A frame phase detector as described in statement 1, wherein said second frame begins with a numerical first edge, representing initial phase of the second frame, defined as a number of sampling delays between an expected location of such numerical first edge and the first counted sampling clock, wherein the frame measurement circuit is preset to the numerical first edge before any said counting of the sampling clocks takes place;",
"the frame phase detector comprising: a means for presetting the frame measurement circuit to said numerical first edge before said counting of the sampling periods of the first interval of the second frame takes place;",
"a means for supplementing said preset numerical first edge by adding following sampling periods counted until the second edge of the second frame is encountered, and a means for capturing and buffering a resulting total number of sampling periods until it is read by a phase processing unit;",
"wherein the resulting total number of the sampling periods represents duration of such first interval of the second frame and is made available for further processing.",
"A frame phase detector as described in statement 1 receiving an incoming wave-form carrying the external frame signal or carrying the external message;",
"the frame phase detector wherein: said detection of the second frame edges from the incoming wave-form, is performed by a circuit synchronized with the local sampling clock and producing a known propagation delay.",
"An FPD as described in statement 1, wherein the frame phase skew is calculated without any accumulation of digitization errors of said intervals phase skews while the single intervals phase skews are still available for intermediate signal processing;",
"the FPD comprising: a means for rounding said counted number of the sampling periods by adding 1 such sampling period to the counted number defining length of said frame interval, wherein ½ of the added sampling period approximates a fraction of the sampling period occurring before said counting of the interval sampling periods and another ½ of the added sampling period approximates a fraction of the sampling period occurring after said counting;",
"whereby such addition of 1 sampling period to every interval measurement, provides all sampling periods occurring between said counted numbers of sampling periods relating to consecutive intervals of the second frame, and reduces a digitization error of any long frame to a time sampling error of a single interval.",
"A frame phase detector as described in statement 1 including a high resolution circuit for extending resolution of phase measurements below a period of the local clock, wherein the high resolution circuit propagates the local clock through a delay line built with serially connected gates producing different phases of the local clock;",
"the frame phase detector comprising: the high resolution circuit using a phase capture register for capturing a state of outputs of the serially connected gates, which the local clock is propagated through, at an edge of the interval of the second frame;",
"or the high resolution circuit using a phase capture register for capturing an edge of the interval of the second frame by using the outputs of the serially connected gates as sampling sub-clocks applied to clocking-in inputs of the phase capture register while said second frame, defined with the frame signal or the frame status, is applied to data inputs of the phase capture register.",
"A frame phase detector as described in statement 1 including a high resolution circuit for extending resolution of phase measurements below the period of the local clock, wherein the high resolution circuit propagates the second frame, defined with the frame signal or the frame status, through a delay line built with serially connected gates producing different phases of the second frame;",
"the frame phase detector comprising: the high resolution circuit using a phase capture register for capturing a phase of an edge of the interval of the second frame by applying the outputs of the serially connected gates which the second frame is propagated through to data inputs of the phase capture register while the local clock is used for clocking the data inputs in;",
"or the high resolution circuit using a phase capture register for capturing a phase of an edge of the interval of the second frame by using the outputs of the serially connected gates-which the second signal frame is propagated through-as clocking in signals while the local clock is applied to data inputs of the phase capture register.",
"A frame phase detector as described in statement 1 including a noise filtering edge detector (NFED) improving reliability and precision of said detection of the second frame edges by removing phase noise from wave-form edges and amplitude glitches from wave-form levels through continues over-sampling and digital filtering of an entire incoming wave-form carrying said external frame signal or said external messages, wherein the incoming wave-form is over-sampled with sampling sub-clocks generated by a delay line built with serially connected gates which the sampling local clock is propagated through, and wave-forms variable length pulses are processed by comparing an edge mask, which provides an expected pattern of wave-form samples corresponding to an edge of the wave-form, with a sequence of wave-form samples surrounding a consecutive analyzed sample;",
"the FPD wherein the NFED further comprises: a wave capturing circuit for capturing results of sampling the incoming wave-form in time instances produced by the outputs of the delay line which the sampling local clock is propagated through;",
"means for performing logical or arithmetic operations on particular samples of the edge mask and their counterparts from the wave-form samples surrounding the consecutive analyzed sample of the captured wave-form;",
"means for using the results of said operations for deciding if said operations can determine a filtered location of an edge of a filtered wave-form, wherein such filtered location is further used for said detection of boundaries of the second frame.",
"Noise Filtering Edge Detector The NFED is directed to signal and data recovery in wireless, optical, or wireline transmission systems and measurement systems.",
"The noise filtering edge detector (NFED) provides digital filtering of waveform pulses transmitting serial streams of data symbols with data rates reaching ½ of maximum clock frequency of IC technology.",
"The NFED enables: continues waveform over-sampling with sampling frequencies 5 times higher than the maximum clock frequency;",
"elimination of phase jitter from edges of the pulses and elimination of amplitude glitches from insides of the pulses as well;",
"and a system for adaptive noise filtering based on analysis of captured unfiltered portions of the over-sampled waveform.",
"The noise filtering edge detectors (NFED) shall be particularly advantageous in system on chip (SOC) implementations of signal processing systems.",
"The NFED provides an implementation of programmable algorithms for noise filtering for a very wide range of low and high frequency wave-forms.",
"The NFED is based on a synchronous sequential processor (SSP) which allows >10 times faster processing than conventional digital signal processors.",
"The NFED comprises: the SSP used for capturing and real time processing of an incoming waveform (see the end of this Subsection);",
"a wave-from screening &",
"capturing circuit (WFSC) (see the end of this Subsection);",
"a programmable control unit (PCU) for supporting adaptive noise filtering and edge detection algorithms;",
"The NFED compares: a captured set of binary values surrounding a particular bit of a captured waveform, with an edge mask comprising a programmed set of binary values.",
"Such comparison produces an indicator of proximity between the surrounded bit and an expected edge of the waveform.",
"The indicator is named edge proximity figure (EPF).",
"Said comparison comprises: performing logical and/or arithmetic operation on any bit of the captured set and its counterpart from the edge mask;",
"integrating results of said operations performed on all the bits of the captured set, in order to estimate the EPF for the surrounded bit;",
"defining a waveform transition area by comparing the EPF with an edge threshold, wherein a set of bits having EPFs exceeding the threshold defines the waveform transition area where an edge is expected.",
"Finding the most extreme EPF by comparing all the EPFs belonging to the same waveform transition area, wherein such EPF identifies a bit position localizing a filtered edge.",
"The NFED further comprises: modulating locations of detected rising and/or falling waveform edges by an edge modulating factor (EMF) used to modify edge thresholds which are subtracted from the EPFs, wherein such reduced EPFs are used for finding edge location;",
"using an edge modulation control register (EMCR) programmed by the PCU, for defining function transforming said EMFs into said modifications of edge thresholds.",
"The NFED still further comprises displacing detected edges by a preset number of bits, in order to compensate for inter-symbol interference ISI or other duty cycle distortions.",
"The NFED further includes: using the WFSC for programmable screening of the over-sampled unfiltered wave-form, and for capturing screened out wave-form intervals, and for communicating said captured intervals and other results to the PCU;",
"programmable waveform analysis and adaptive noise filtering algorithms;",
"edge mask registers for providing said edge masks used for detecting rising and/or falling waveform edges;",
"edge threshold registers for providing said edge thresholds used for detecting rising and/or falling waveform edges;",
"edge displacement registers for providing said edge displacement numbers used for shifting detected rising and/or falling edges by a programmable number of bits of waveform processing registers;",
"filter control registers which control;",
"said logical and/or arithmetic operations conducting the comparison of captured waveform bits with the edge mask, and said edge displacements in the processed waveforms;",
"using the PCU for calculating and loading said edge mask registers and/or said edge threshold registers and/or said edge displacement registers and/or said filter control registers;",
"using the PCU for controlling said calculations of the EMF by presetting the EMCR in accordance with adaptive noise filtering algorithms.",
"using the PCU for controlling and using the WFSC operations for implementing adaptive filters by controlling noise filtering edge detection stages of the SSP.",
"Further description of the NFED is provided below.",
"The NFED comprises: a wave capturing circuit for capturing an incoming wave-form sampled by sub-clocks produced by the outputs of the delay line which the sampling clock is propagated through;",
"a circuit performing logical or arithmetic operations on particular samples of the edge mask and their counterparts from the wave-form samples surrounding the consecutive analyzed sample of the captured wave-form;",
"using the results of said operations for defining a filtered location of an edge of the waveform.",
"Such NFED further comprises: a filter arithmometer for comparing the edge mask with the captured wave-form in order to introduce noise filtering corrections of the edges of the filtered wave-form;",
"a filter mask register providing the edge mask which is compared with the captured wave-form of an input signal and/or filter control register which provides code for controlling operations of said filter arithmometer in order to provide said corrections of the filtered wave-form.",
"The NFED compares said edge mask samples of the expected edge pattern with samples from a consecutive processed region of the captured wave-form.",
"Consequently the NFED comprises: accessing any said consecutive processed region of the captured wave-form and using such region as comprising samples corresponding to the edge mask samples;",
"selection of a consecutive sample from the edge mask and simultaneous selection of a corresponding consecutive sample from the processed region of the captured wave-form;",
"calculating a correlation component between such selected samples by performing an arithmetical or logical operation on said selected samples;",
"calculating a digital correlation integral by adding said correlation components calculated for single samples of the edge mask.",
"The NFED includes calculating correlation integrals for said consecutive processed regions uniformly spread over all the captured wave-form, wherein the calculated correlation integrals are further analyzed and locations of their maximums or minimums are used to produce said filtered locations of said edges of the filtered wave-form;",
"Such NFED operations comprise: moving said processed region by a programmable number of samples positions of the captured wave-form;",
"storing and comparison of said correlation integrals calculated for different processed regions, in order to identify said maximums or minimums and their locations;",
"using said locations of said maximums or minimums for producing the filtered locations of the edges of the filtered wave-from.",
"The NFED includes compensation of inter-symbol interference (ISI) or other predictable noise by adding a programmable displacement to said filtered location of the edge of the wave-form.",
"Therefore the NFED comprises: programmable amendment of the filtered location of the wave-form edge by presetting said programmable displacement with a new content;",
"using such newly preset displacement for shifting the filtered location of the next detected edge.",
"The NFED includes compensation of periodical predictable noise with programmable modulations of said filtered locations of the wave-form edges by using an edge modulating factor (EMF) for a periodical diversification of said edge thresholds corresponding to different said regions of the wave-form;",
"wherein the NFED comprises: modulation of the filtered locations of the wave-form edges by using the edge modulating factor (EMF) for modulating said edge thresholds;",
"subtracting such modulated thresholds from the correlation integrals calculated in said different wave-form regions;",
"using such reduced correlation integrals for locating said maximums defining locations of filtered edges.",
"whereby said EMF provides such modulation of the edge thresholds, that predictable noise introduced to consecutive wave-form samples by known external or internal sources, is compensated.",
"The NFED further includes: using an edge modulation control register (EMCR) programmed by the PCU, for said modulation of the edge thresholds.",
"The NFED comprises: sequential processing stages configured into a sequential synchronous processor driven synchronously with said sampling clock.",
"The NFED further comprises parallel processing phases implemented with said synchronous sequential processors;",
"wherein: said parallel processing phases are driven by clocks having two or more times lower frequencies than said sampling clock;",
"consecutive parallel phases are driven by clocks which are shifted in time by one or more periods of said sampling clock;",
"The NFED comprises using multiple noise filtering sequential stages in every parallel processing phase for extending said wave-form filtering beyond a boundary of a single phase.",
"Such NFED further includes an over-sampled capturing of consecutive wave-form phases in corresponding phases wave registers which are further rewritten to wave buffers with overlaps which are sufficient for providing all wave samples needed for a uniform filtering of any edge detection despite crossing boundaries of the wave buffers which are loaded and used during different said phases;",
"wherein the NFED comprises: rewriting the entire wave register belonging to one phase into the wave buffer of the same phase and rewriting an end part of said wave register into a front part of the next phase wave buffer, while the remaining part of the next wave buffer is loaded from the wave register belonging to the next phase;",
"whereby every wave buffer contains entire said wave-form regions needed for calculating said EPF's corresponding to the samples belonging to the phase covered by this buffer.",
"The NFED includes: merging of said parallel processing phases, wherein multiple said parallel processing phases are merged into a smaller number of parallel phases or into a single processing phase, when passing from one said sequential processing stage to the next sequential stage.",
"splitting of said parallel processing phases, wherein one said processing phase is split into multiple parallel processing phases or multiple parallel processing phases are split into even more parallel phases, when passing from one said sequential processing stage to the next sequential stage.",
"The NFED includes said PCU for analyzing results of said real time signal processing form the SSP and for controlling operations of the SSP;",
"wherein the PCU comprises: means for reading results of captured signal processing from the SSP;",
"means for programming the filter mask register and/or the filter control register and/or said presetting of the programmable displacement and/or the edge modulating factor, which are applied for achieving said filtering of the captured wave-forms.",
"The NFED includes a wave-form screening and capturing circuit (WFSC) for capturing pre-selected intervals of unfiltered over-sampled wave-form;",
"wherein the WFSC comprises: using programmable screening masks and/or programmable control codes for verifying incoming wave-form captures for compliance with said programmable screening masks.",
"buffering captured wave-form for which the pre-programmed compliance or non-compliance has been detected, or for counting a number of said detections;",
"communicating said buffered wave-form and a detections counter to the PCU.",
"The PCU reads resulting captured signals from the WFSC and controls operations of the WFSC;",
"wherein the PCU comprises: programming the screening masks and/or the control codes for performing said verification of captured wave-forms compliance or non-compliance with said screening patterns;",
"reading verification results and/or reading captured wave-forms which correspond to the preprogrammed verification criteria.",
"The NFED includes using said PCU for adaptive noise filtering;",
"wherein the PCU comprises: means for programmable waveform analysis;",
"means for loading edge mask registers which provide said edge masks used for detecting rising and/or falling wave-form edges;",
"or means for loading edge threshold registers which provide said edge thresholds used for detecting rising and/or falling waveform edges;",
"or means for loading edge displacement registers which provide said edge displacements used for shifting detected rising and/or falling edges by a programmable number of samples positions of the captured wave-form;",
"or means for loading filter control registers which control said logical and/or arithmetic operations conducting the comparison of captured wave-form samples with the edge mask, and said edge displacements in the processed wave-forms;",
"or means for controlling said EMF by presetting the EMCR in accordance with adaptive noise filtering algorithms.",
"General definition of the SSP is provided below.",
"The SSP includes real time capturing and processing of in-coming wave-form and a programmable computing unit (PCU) for controlling SSP operations and supporting adaptive signal analysis algorithms.",
"Said SSP comprises an over-sampling of incoming wave-form level by using a locally generated sampling clock and its sub-clocks generated by the outputs of serially connected gates which the sampling clock is propagated through.",
"If an active edge of the wave-form is detected by capturing a change in a wave-form level, the position of the captured signal change represents an edge skew between the wave-form edge and an edge of the sampling clock.",
"In addition to the above wave-form capturing method, the SSP includes 3 other methods of the edge skew capturing which are defined below: the sampling clock captures the outputs of serially connected gates which the incoming wave-form is propagated through;",
"the outputs of serially connected gates which the incoming wave-form is propagated through, provide wave-form sub-clocks which capture the sampling clock.",
"the incoming wave-form captures the outputs of serially connected gates which the sampling clock is propagated through;",
"The above mentioned edge skew capturing methods further include: using falling edges of said sub-clocks for driving clock selectors which select parallel processing phases during which positive sub-clocks are enabled to perform said edge skew capturing, or using rising edges of said sub-clocks for driving selectors which select parallel processing phases during which negative sub-clocks are enabled to perform said edge skew capturing;",
"using serially connected clock selectors for enabling consecutive sub-clocks, in order to assure that consecutive sub-clocks will target appropriate consecutive bits of appropriate capture registers.",
"The SSP invention includes using said serially connected gates: as being an open ended delay line;",
"or being connected into a ring oscillator which can be controlled in a PLL configuration;",
"or being connected into a delay line which can be controlled in a delay locked loop (DLL) configuration.",
"Every said edge skew amounts to a fraction of a sampling clock period.",
"The SSP comprises measuring time intervals between active wave form edges, as being composed of said edge skew of a front edge of the incoming waveform, an integer number of sampling clock periods between the front edge and an end edge, and said edge skew of the end edge of the wave-form.",
"The SSP further comprises a parallel multiphase processing of incoming signal by assigning consecutive parallel phases for the capturing of edge skews and/or processing of other incoming wave-form data with clocks which correspond to consecutive sampling clocks.",
"Consequently the SSP invention comprises using 1 to N parallel phases which are assigned for processing incoming signal data with clocks corresponding to sampling clock periods numbered from 1 to N, as it is further described below: circuits of phase1 process edge skews or phase skews or other incoming signal data with a clock which corresponds to the sampling clock period number 1;",
"circuits of phase2 process edge skews or phase skews or other incoming signal data with a clock which corresponds to the sampling clock period number 2;",
"finally circuits of phase N process edge skews or phase skews or other incoming signal data with a clock which corresponds to the sampling clock period number N. Said parallel multiphase processing allows N times longer capturing and/or processing times for said multiphase stages, compared with a single phase solution.",
"The SSP includes parallel stage processing of incoming signal by providing multiple processing stages which are driven by the same clock which is applied simultaneously to inputs of output registers of all the parallel stages.",
"The SSP further comprises a synchronous sequential processing of incoming signal by using multiple serially connected processing stages with every stage being fed by data from the previous stage which are clocked-in by a clock which is synchronous with the sampling clock.",
"Since every consecutive stage is driven by a clock which is synchronous to the same sampling clock, all the stages are driven by clocks which are mutually synchronous but may have some constant phase displacements versus each other.",
"The SSP further comprises: merging of processing phases which occurs if multiple parallel processing phases are merged into a smaller number of parallel phases or into a single processing phase, when passing from a one processing stage to a next processing stage;",
"splitting of processing phases which occurs if one processing phase is split into multiple processing phases or multiple processing stages are split into even more processing stages, when passing from a one processing stage to a next processing stage.",
"The SSP includes a sequential clock generation (SCG) circuit which uses said clock selectors and said sub-clocks: to generate SSP clocks which drive said parallel phases and said sequential stages, and to generate selector switching signals for said merging and splitting of processing phases.",
"The SSP includes time sharing of said parallel phases: which is based on assigning a task of processing of a newly began wave-form pulse to a next available parallel processing phase.",
"The SSP comprises a sequential phase control (SPC) circuit, which uses results of a wave edge decoding and said SSP clocks, for performing said time sharing phase assignments and for further control of operations of an already assigned phase.",
"The SSP comprises passing outputs of a one parallel phase to a next parallel phase, in order to use said passed outputs for processing conducted by a following stage of the next parallel phase.",
"The outputs passing is performed: by re-timing output register bits of the one phase by clocking them into an output register of the next parallel phase simultaneously with processing results of the next parallel phase.",
"The SSP further comprises all the possible combinations of the above defined: parallel multiphase processing, parallel stage processing, synchronous sequential processing, merging of processing phases, splitting of processing phases, and outputs passing.",
"The SSP includes processing stage configurations using selectors, arithmometers, and output registers, which are arranged as it is defined below: input selectors select constant values or outputs of previous stages or outputs of parallel stages or an output of the same stage to provide arithmometer inputs, and arithmometer output is clocked-in to an output register by a clock which is synchronous to the sampling clock;",
"multiple arithmometers are fed with constant values or outputs of previous stages or outputs of parallel stages or an output of the same stage, and an output selector selects an arithmometer output to be clocked-in to an output register by a clock synchronous to the sampling clock;",
"the above defined configuration as being supplemented by using an output of an output selector of a parallel processing stage for controlling output selector functions.",
"Proper arrangements of said parallel and sequential combinations and said stages configurations provide real time processing capabilities for very wide ranges of signal frequencies and enable a wide coverage of very diversified application areas.",
"Summary of the WFSC is provided below (see the Subsection 4 of the next section for preferred embodiment of WFSC).",
"The wave-form screening and capturing circuits (WFSC) comprises: using programmable data masks and programmable control codes for verifying incoming wave-form captures for compliance or non-compliance with a pre-programmed screening patterns;",
"buffering captured data for which the pre-programmed compliance or non-compliance have been detected;",
"counting a number of the above mentioned detections;",
"communicating both the buffered captured data and the number of detections, to an internal control unit and/or to an external unit;",
"using programmable time slot selection circuits for selecting a time interval for which wave-form captures shall be buffered and communicated to the PCU.",
"Said PCU comprises implementation of the functions listed below: programming of verification functions and patterns for checking captured wave-forms for compliance or non-compliance with the patterns;",
"reading verification results and reading captured wave-forms which correspond to the preprogrammed verification criteria;",
"reading captured wave-forms which can be pre-selected by the PCU arbitrarily or based on other inputs from the SSP;",
"programming of noise filtering functions and noise filtering masks for filtering captured wave-forms;",
"reading results of real-time wave-form processing from the SSP, processing the results and providing control codes and parameters for further real-time wave-form processing in the SSP, in accordance with adaptive signal processing algorithms;",
"reading output data from the SSP, interpreting the data, and communicating the data to external units.",
"Summary of SCCS SCCS introduced above comprises methods, systems and devices described below (listed as claims in PCT/CA2006/001120).",
"A phase synthesizer providing programmable modifications of a phase of a synthesized clock by unlimited number of gate delays per a modification step with step resolution matching single gate delay at steps frequencies ranging from 0 to ½ of maximum clock frequency;",
"the phase synthesizer comprising: a delay control circuit connected to a programmable control unit (PCU) wherein the delay control circuit defines size and frequency of phase delay modifications of the synthesized clock versus a reference clock, the delay control circuit also having a terminal connected to reference sub-clocks generated by a reference propagation circuit or connected to odd/even sub-clocks generated by an odd/even phase selector;",
"the reference propagation circuit, connected to the reference clock, consisting of serially connected gates wherein outputs of the gates generate the reference sub-clocks providing variety of phase delays versus the reference clock;",
"an odd/even phase selector, connected to the reference sub-clocks, for splitting the reference sub-clocks by generating separate odd sub-clocks and even sub-clocks, wherein the odd sub-clocks begin during odd cycles of the reference clock and the even sub-clocks begin during even cycles of the reference clock;",
"a clock selection register loaded by the odd sub-clocks and by the even sub-clocks with the outputs of the delay control circuit, wherein the odd sub-clocks or the even sub-clocks beginning during an earlier cycle of the reference clock download outputs of the delay control circuit which select the even sub-clocks or the odd sub-clocks beginning during a later cycle of the reference clock for providing the synthesized clock;",
"an output selector connected to the output of the clock selection register and to the outputs of the odd/even phase selector, wherein the output selector uses inputs from the clock selection register for selecting output of the odd/even phase selector which is passed through the output selector for providing the synthesized clock.",
"A phase synthesizer providing programmable modifications of a phase of a synthesized clock by a programmable number of gate delays per a modification step with step resolution matching single gate delay at steps frequencies ranging from 0 to ½ of maximum clock frequency, wherein uncontrolled phase transients inherent for frequency synthesizers are eliminated;",
"the phase synthesizer comprising: a reference propagation circuit, connected to a reference clock, consisting of serially connected gates wherein outputs of the gates generate reference sub-clocks providing variety of phase delays versus the reference clock;",
"a delay control circuit, connected to a programmable control unit (PCU) and to the reference propagation circuit, for applying phase delay modifications of the synthesized clock versus a reference clock by modifying selections of said reference sub-clocks chosen for sourcing the synthesized clock;",
"the PCU, connected to an interrupt signal generated by the delay control circuit, for supplying programmable sequences of said phase delay modifications in response to interrupt signals sent by the delay control circuit.",
"A noise filtering edge detector (NFED) for recovering digital signal transitions and their phases from noisy waveforms while assuming ideal signal shape between the transitions, in order to identify digitally transmitted data, by continues over-sampling and digital filtering of the incoming waveform based on comparing an edge mask, representing an expected pattern of wave-form samples corresponding to an edge of the original wave-form, with a sequence of wave-form samples surrounding a consecutive analyzed sample;",
"the NFED comprising: a wave capturing circuit for capturing results of sampling the incoming wave-form in time instances produced by the outputs of the delay line which the sampling clock is propagated through;",
"a correlation calculating circuit for performing logical or arithmetic operations on particular samples of the edge mask and their counterparts from a wave samples region surrounding the consecutively analyzed sample of the captured wave-form, in order to calculate a correlation integral between the wave samples region and the edge mask;",
"a proximity estimating circuit for deciding if there is an edge occurrence at the consecutively analyzed sampling instant based on processing of such correlation integrals calculated for samples belonging to a surrounding wave region.",
"A noise filtering edge detector (NFED) for recovering digital signal transitions and their phases from noisy waveforms while assuming ideal signal shape between the transitions, in order to identify digitally transmitted data, by continues over-sampling and digital filtering of the incoming waveform based on comparing an edge mask, representing an expected pattern of wave-form samples corresponding to an edge of the original wave-form, with a sequence of wave-form samples surrounding a consecutive analyzed sample;",
"the NFED comprising: a wave capturing circuit, connected to a sampling clock and to the incoming waveform, for continues over-sampling of the incoming wave-form;",
"a correlation calculating circuit for performing logical or arithmetic operations on particular samples of the edge mask and their counterparts from a wave samples region surrounding the consecutively analyzed sample of the captured wave-form, in order to calculate a correlation integral between the wave samples region and the edge mask;",
"a proximity estimating circuit for deciding if there is an edge occurrence at the consecutively analyzed sampling instant based on processing of such correlation integrals calculated for samples belonging to a surrounding wave region.",
"A hybrid phase locked loop (HPLL) producing a stable low jitter output clock while enabling very high frequency multiplication factor which can be programmed to any real number belonging to a continues range from 1 to tens of thousands, wherein a low frequency reference clock multiplied by such factor produces such HPLL output clock while a desirable preprogrammed phase and frequency transfer function (PFTF) is maintained by a micro-controller (MC);",
"the HPLL comprising: an analog phase locked loop (APLL) having one input of it's analog phase detector (APD) connected to the HPLL output clock while another APD input is connected to a local synthesized clock produced by a local phase synthesizer (LPS) connected to the HPLL output clock;",
"a frame phase detector (FPD) for measuring a digital phase error between the output clock and the reference clock, wherein such digital phase error is read by said micro-controller which controls operations of said local phase synthesizer;",
"a digital phase locked loop (DPLL) comprising the frame phase detector and the micro-controller and the local phase synthesizer, wherein the MC drives said local phase synthesizer into producing phase differences between the APD inputs needed for implementing said preprogrammed PFTF between the output clock and the reference clock.",
"An open-ended software controlled synchronizer (OE-SCS) using micro-controller (MC) subroutines for providing programmable phase frequency transfer function (PFTF) between a reference clock and an output clock generated by a phase synthesizer totally avoiding uncontrolled phase transients inherent for frequency synthesizers, wherein such phase synthesizer works in an open loop configuration enabling inherently stable generation of said output clock and maintains low phase jitter of the output clock independent of phase jitter levels in the reference clock;",
"the OE-SCS comprising: a frame phase detector (FPD) measuring digital phase error between a local clock and said reference clock;",
"the MC for reading said digital phase error and for processing it and for driving said phase synthesizer into generating the output clock implementing said PFTF between the output clock and the reference clock;",
"the phase synthesizer, connected to a local clock and controlled by the MC, for producing said output clock in the open loop configuration.",
"The OE-SCS configuration of claim 6 further including an external synchronization mode (ESM) enabling analog phase locking of the output clock to an external clock which can be provided by a local reference clock or an output clock from a backup synthesizer unit, wherein such OE-SCS with ESM comprises: an analog PLL (APLL-ESM), connected alternatively to the phase synthesizer output clock or to such external clock, for producing such phase locked output clock.",
"The OE-SCS configuration of statement 7, wherein the APLL-ESM further comprises: a reference selector (RFS) for selecting the phase synthesizer output clock or said external clock as sourcing an APLL-ESM reference clock which the output clock has to be phase locked to.",
"A heterodyne timing configuration of a software controlled synchronizer (HTC-SCS) using a local oscillator which can have very low frequency and a micro-controller (MC) for securing programmable phase frequency transfer functions (PFTF) between a reference clock and an output clock while enabling very high frequency multiplication factor which can be programmed to any real number belonging to a continues range from 0 to tens of thousands, wherein very low phase jitter of the output clock is maintained independent of phase jitter levels in the reference clock;",
"the HTC-SCS comprising: a frame phase detector (FPD) for measuring a digital phase error between the reference clock and the output clock;",
"the MC for reading the digital phase error and for implementing the PFTF by controlling operations of a phase synthesizer defining analog phase errors produced by an analog phase detector (APD) of an analog phase locked loop (APLL), wherein such analog phase errors control phase and frequency of the output clock produced by the APLL;",
"the phase synthesizer, controlled by the MC while connected to the output clock and supplying an input of the APD, for introducing the analog phase errors programmed by the MC;",
"an analog phase locked loop (APLL), having one input connected to the output of the phase synthesizer while another input is connected to the output clock, for generating said output clock;",
"a digital phase locked loop (DPLL) using the FPD and the MC and the phase synthesizer for controlling operations of the APLL in order to implement the PFTF between the output clock and the reference clock.",
"10.",
"The HTC-SCS of statement 9 further including the HPLL of statement 5 in order to multiply a very low frequency of an inexpensive local oscillator to much higher frequency range needed to synthesize the output clock required;",
"such configuration comprising: an additional frame phase detector (A-FPD) for measuring a digital phase error between the output clock and the local oscillator applied as an additional reference clock;",
"an additional DPLL subroutine in the MC for implementing another PFTF applicable to the relation between the output clock and the additional reference clock.",
"11.",
"The HTC-SCS of statement 9 further including an external synchronization mode (ESM) enabling analog phase locking of the output clock to an external clock which can be provided by a local reference clock or an output clock from a backup synthesizer unit, wherein such HTC-SCS with ESM comprises: an additional clock selector (CLK-SEL) inserted between the output clock and said another input of the APLL for providing alternative selection of the output clock or such external clock for being connected to said another input of the APLL.",
"12.",
"The OE-SCS configuration of statement 6 or the HTS-SCS of statement 9 further including the NFED of claim 4 for time domain phase noise filtering from an external reference waveform in order to produce a filtered reference waveform used further on as the reference clock, wherein the NFED can enable by one order more accurate phase detection when the external reference waveform is coming from a noisy serial link such as those utilized by network time protocols;",
"wherein such synchronizer configuration comprises: the NFED circuit, controlled by the MC and connected to the MC and to the external reference waveform, for producing the filtered reference waveform which is further used as the reference clock by the synchronizer.",
"13.",
"The OE-SCS configuration of statement 6 or the HTS-SCS of statement 9 further including a time stamp decoder (TSD) circuit for decoding time stamp messages received from a remote serial link in order improve accuracy of phase/frequency detection by eliminating timing uncertainties caused otherwise by interrupts decoding software sub-routines;",
"wherein such synchronizer configuration comprises: the time stamp decoder, connected to a serial link receiver recovering a message signal, for producing time stamp messages communicated to the MC and for signaling time stamp detections to the FPD;",
"network time protocol subroutines residing in the MC for reading the digital phase errors occurring between message signal transitions and for reading the time stamp messages and for controlling operations of the phase synthesizer;",
"wherein such MC subroutines implement said programmed PFTF between the output clock and the reference clock signal defined with pulses occurring between those message signal transitions which are specified by stamp messages as signaling arrivals of such stamp messages.",
"14.",
"A frame phase detector (FPD) for measuring a frame phase skew between a first frame consisting of a programmable expected number of sampling local clocks, and a second frame defined with a series of time intervals located between second frame edges defined by changes of an external frame signal or by changes of a frame status driven with external messages such as time stamps, wherein a frame measurement circuit captures a number of said sampling periods occurring during an interval of the second frame and a phase processing unit subtracts the captured number from the expected number representing expected duration of the corresponding interval of the first frame;",
"wherein-the frame phase detector comprises: a circuit for a detection of said second frame edges, by detecting said changes of the external frame signal, or by detecting said changes of the frame status driven by the external messages;",
"the frame measurement circuit using the sampling local clock, which is a higher frequency signal, to measure said time intervals of the second frame having lower frequency, wherein the frame measurement circuit counts said sampling periods occurring during every interval of the second frame and captures and buffers the counted value until it is read by a phase processing unit;",
"the phase processing unit for subtracting the expected number of the sampling periods from the counted number of the sampling periods, in order to calculate an interval phase skew between the expected interval of the first frame and the corresponding interval of the second frame.",
"a circuit and/or a subroutine for combining said interval phase skews of particular frame intervals into said frame phase skew.",
"15.",
"A frame phase detector as described in statement 14, wherein said second frame begins with a numerical first edge, representing initial phase of the second frame, defined as a number of sampling delays between an expected location of such numerical first edge and the first counted sampling clock, wherein the frame measurement circuit is preset to the numerical first edge before any said counting of the sampling clocks takes place;",
"the frame phase detector comprising: a circuit for presetting the frame measurement circuit to said numerical first edge before said counting of the sampling periods of the first interval of the second frame takes place;",
"a circuit and/or a subroutine for supplementing said preset numerical first edge by adding following sampling periods counted until the second edge of the second frame is encountered, and a means for capturing and buffering a resulting total number of sampling periods until it is read by a phase processing unit;",
"wherein the resulting total number of the sampling periods represents duration of such first interval of the second frame and is made available for further processing.",
"16.",
"A frame phase detector as described in statement 14 receiving an incoming wave-form carrying the external frame signal or carrying the external message;",
"the frame phase detector wherein: said detection of the second frame edges from the incoming wave-form, is performed by a circuit synchronized with the local sampling clock and producing a known propagation delay.",
"17.",
"An FPD as described in statement 14, wherein the frame phase skew is calculated without any accumulation of digitization errors of said intervals phase skews while the single intervals phase skews are still available for intermediate signal processing;",
"the FPD comprising: a circuit and/or a subroutine for rounding said counted number of the sampling periods by adding 1 such sampling period to the counted number defining length of said frame interval, wherein ½ of the added sampling period approximates a fraction of the sampling period occurring before said counting of the interval sampling periods and another ½ of the added sampling period approximates a fraction of the sampling period occurring after said counting;",
"whereby such addition of 1 sampling period to every interval measurement, provides all sampling periods occurring between said counted numbers of sampling periods relating to consecutive intervals of the second frame, and reduces a digitization error of any long frame to a time sampling error of a single interval.",
"10.",
"Receiver Synchronization Techniques RST comprises methods and systems utilizing said referencing frame for achieving substantially more accurate and more stable of synchronization OFDM receiver to composite signal frame.",
"Furthermore RST comprises methods and systems enabling more accurate recovery of said referencing frame from OFDM data tones only and thus RTS enables both;",
"better accuracy and improved efficiency resulting from elimination of preambles or pilots needed previously.",
"RST includes a method, a system and an apparatus for recovering said referencing frame signal from received composite frames carrying transmitted data or control pilot information, and for using such recovered referencing frame for synchronizing timing and frequency of receiver's local oscillator and data recovering circuits.",
"The RST comprises a method for recovering a referencing frame signal from OFDM composite frames carrying transmitted data or control pilot information, and for using such recovered referencing frame for synchronizing timing and frequency of receiver's local oscillator and data sampling circuits wherein a recovered frame lengths of such referencing frame interval represents a combined length of single or multiple composite frame intervals originating this referencing frame interval;",
"wherein such RST comprises: detection of boundaries of the data carrying frames or pilot frames by processing received OFDM composite signal or a recovered sub-carrier signal;",
"using such boundaries detections for specifying said referencing frame signal, wherein such detections delimit said referencing frame interval;",
"calculating a lengths difference between the recovered frame length and a measured frame length wherein such measured frame length of an equivalent symbol frame is the combined length of symbol frame intervals corresponding to said composite frame intervals originating this referencing frame, wherein the symbol frame defines a set of composite signal samples belonging to the same OFDM composite frame;",
"calculating frequency offset between the referencing frame and such equivalent symbol frame by dividing such lengths difference by the recovered frame lengths or by the measured frame lengths;",
"using such frequency offset for adjusting frequency of said local oscillator in order to maintain frequency alignment between a local oscillator clock and an OFDM transmitter clock;",
"using such length difference for measuring a time offset between the composite frame and the symbol frame;",
"using such time offset to synthesize phase of the symbol frame from the local oscillator clocks, in order to maintain correct time alignment between the symbol frame and the composite signal frame.",
"The RST further comprises: application of time or frequency domain filters and/or statistical methods for evaluating reliability of such boundary detection, wherein: if said boundary detection signal is evaluated as reliable, it is used for delimiting said referencing frame interval corresponding to said single or multiple symbol frames;",
"if said boundary detection signal is dismissed as unreliable, said measured frame length of equivalent symbol frame is increased by the length of symbol frame interval corresponding the composite frame interval which the boundary detection has failed for.",
"The RST further includes a frequency locked phase synthesis (FLPS) method and system for producing said symbol frame maintaining frequency and phase alignment to said referencing frame providing frequency and phase transmittal from an external source, wherein a frequency locked loop utilizes said local oscillator clock for producing frequency aligned symbol frame and a programmable phase synthesizer utilizes such local oscillator clock for producing the frequency and phase aligned symbol frame;",
"wherein such FLPS comprises: measuring a frequency error between the referencing frame and the symbol frame;",
"using such frequency error for maintaining frequency alignment between the symbol frame and the referencing frame by controlling frequency of said local oscillator clock;",
"presetting said phase synthesizer to an initial phase displacement needed to maintain a phase alignment between the referencing frame and the symbol frame;",
"measuring a phase error between the referencing frame and the symbol frame;",
"using such phase error for maintaining said phase alignment between the symbol frame and the referencing frame by controlling phase synthesis functions of said phase synthesizer from the local oscillator clock.",
"Such RST methods systems and apparatus are described below.",
"The RST comprises: detection of boundaries of the data carrying frames or pilot frames by processing received OFDM composite signal or recovered sub-carrier signal;",
"using such boundaries detections for specifying said referencing frame signal, wherein such detections delimit referencing frame interval and/or are utilized to define a nominal number of local oscillator output clocks expected to occur during such interval if frequency offset between the local oscillator clock and a transmitter clock equals zero;",
"The RTS further comprises using such referencing frame signal for measuring a normalized phase skew (equal to said frequency offset) and said time offset between the receiver and transmitter, wherein: the local oscillator clock is counted during such referencing frame interval, and the counted value is buffered until it is used for calculating a phase skew between a local oscillator interval consisting of said nominal number of local oscillator clocks and the referencing frame interval;",
"said phase skew is calculated as equal to a difference between the counted number of said local oscillator clocks and the nominal number;",
"said normalized phase skew is calculated by dividing such phase skew by the nominal number;",
"such normalized phase skew is used for synchronizing local oscillator frequency to a transmitter oscillator frequency;",
"time offset is measured utilizing a phase difference between the referencing frame and a receiver symbol frame which defines a set of composite signal samples carrying an OFDM symbol, or between the referencing frame and an local oscillator frame consisting of the nominal number of said local oscillator clocks;",
"such time offset is used to synthesize phase of the receiver symbol frame from the local oscillator clocks, in order to maintain correct time displacement between the receiver symbol frame and the composite signal frame.",
"The RST includes using such boundary detections for defining referencing frame intervals corresponding to multiple composite frames detected and thus such inter-detection intervals can represent multiple OFDM symbol intervals.",
"Accuracy of time offset measurement (evaluating timing difference between such boundary detection and a corresponding boundary of local symbol frame) is determined by a pilot/preamble form and/or processing method used.",
"Said frequency offset (equal to the normalized phase skew) measured over referencing frame interval is derived by dividing said phase skew, detected within the interval, by the expected interval length specified by the nominal number.",
"Accuracy of such phase skew detection is similar to that of the time offsets, since all of them are defined using said boundary detections.",
"Consequently such use of said referencing frame consisting of such prolonged intervals, greatly improves accuracy of frequency offset measurements.",
"RST includes: maintaining known or predictable processing delay between reception of composite frame samples supplying direct or embodied definition of composite frame boundary, and a detection signal of such frame boundary produced by said synchronous processor operating synchronously with the local oscillator while processing such composite signal samples;",
"The RST further comprises: using the synchronous sequential processing method and circuit (such SSP is defined in Subsection 8 of SUMMARY OF THE INVENTION), for implementing such synchronous processor maintaining said known or predictable processing delay.",
"RST comprises application of time or frequency domain filters and/or statistical methods for evaluating reliability of such boundary detections, wherein: if said boundary detection signal is evaluated as reliable, it is used for delimiting said referencing frame interval corresponding to a singular or multiple said received symbol frames;",
"if said boundary detection signal is dismissed as unreliable;",
"an expected filtered lengths of said symbol frame period specifies generation time of a signal delimiting said referencing frame interval, or said nominal number of local oscillator clocks, corresponding to zero frequency offset within the last symbol frame, is added to said nominal number, corresponding to zero frequency offset within the current referencing frame interval, instead of generating such delimiting signal.",
"The RST covers both versions explained below: utilizing said conventional DSP techniques and processors, implemented already by conventional solutions for the time offset measurement, for the detection of composite frame boundaries;",
"or using said real-time synchronous processing techniques for such detection of composite frame boundaries (by ˜10× more accurate than that of such conventional DSP techniques).",
"Even if such conventional less accurate boundary detection is implemented;",
"said RTS frequency offset measurement (10 times more accurate) will similarly improve amount of time offset introduced between consecutive boundary detections.",
"Therefore time offset tracking and protection from any inter-symbol interference will be greatly improved as well, despite implementing such less accurate boundary detection.",
"RST includes an inherently stable frequency locked phase synthesis (FLPS) method and system producing said symbol frame maintaining frequency and phase alignment to a referencing frame providing frequency and phase transmittal from an external source, wherein a frequency locked loop utilizes an oscillator for producing a frequency aligned oscillator clock and a programmable phase synthesizer utilizes such frequency aligned oscillator clock for producing the frequency and phase aligned symbol frame (see FIG. 13 and FIG. 15 );",
"wherein: the oscillator clock is counted during an interval of the referencing frame, and the counted value is buffered until it is used for calculating a phase skew between an oscillator nominal frame, consisting of a nominal number of said oscillator clocks, and said referencing frame, wherein the nominal number is such number of oscillator clocks which is expected to occur during such referencing frame interval if the phase skew equals zero;",
"said phase skew is calculated as equal to a difference between the counted number of said oscillator clocks and the nominal number;",
"if said referencing frame intervals are expected to have varying lengths specified by their nominal numbers varying accordingly, a normalized phase skew is calculated by dividing such phase skew by the nominal number assigned to such interval;",
"said phase skew or normalized phase skew is applied back to the oscillator, in order to maintain said frequency alignment of the oscillator clock to the referencing frame;",
"the referencing frame is applied to the phase synthesizer which utilizes said such oscillator clock for synthesizing said symbol frame maintaining frequency and phase alignment to the referencing frame;",
"wherein such phase synthesizer (PS) (described in Subsections 5 and 6 of SUMMARY OF THE INVENTION) has its phase synchronization acquisition initialized by presetting initial phase of the synthesized frame (as it is exemplified in Subsection 5 of DESCRIPTION OF THE PREFERRED EMBODIMENT).",
"Furthermore RST comprises a second version of the FLPS offering better stability than that of conventional phase locked loops combined with highly accurate phase control (see FIG. 14 );",
"wherein the last step of the described above first version is replaced with the 2 steps listed below: phase error (time offset) is measured as a phase difference between the referencing frame interval and a symbol frame interval produced by the phase synthesizer;",
"such phase error is applied back to the phase synthesizer which utilizes said oscillator clocks for synthesizing the symbol frame maintaining frequency and phase alignment to the referencing frame.",
"Such phase synthesizer can be implemented;",
"by utilizing methods and circuits defined in said Subsections 5 and 6 of this section.",
"Such second version comprises using much simpler phase synthesizer (without phase jitter control &",
"reduction), which can be implemented as modulo (nominal-number) counter of oscillator clocks wherein such phase error is applied as counter preset value.",
"In addition to the stability improvements, both FLPS versions explained above enable by one order (˜10×) faster acquisition of frequency/phase alignment than that of conventional configurations for phase/frequency synchronization or control.",
"Such much faster synchronization acquisition shall be advantageous;",
"in reducing mobile phone hand-over losses, or improving reliability of Wi/Fi or WiMAX connection switching.",
"RST comprises methods and systems enabling recovery of referencing frame phase (i.e. time offset) from OFDM data sub-carriers (or tones) only, without any use of bandwidth consuming preambles or pilot tones needed in conventional solutions.",
"Such phase (time offset) recovery from data sub-carriers (PRDS) methods comprise using said real-time synchronous processing techniques for recovering amplitudes and phases of sinusoidal cycles or half-cycles of a sub-carrier (tone) selected as being most reliable based on previous training session and/or on-fly channel evaluation.",
"Such synchronous processing techniques are shown in the U.S. 60/894,433 claimed as priority application.",
"Such synchronous processing performed in phase with OFDM waveform capturing circuit, uses frequency sampling filters for recovering time domain sinusoidal representations of two tones (sub-carrierss) elected as being reliable enough and spaced sufficiently in frequency domain.",
"Every half-cycle of such recovered sinusoid identifies phase and amplitude of the tone (or sub-carrier) signal.",
"Such redundancy enables using statistical and deterministic filtering methods, much more efficient than DFT/FFT averaging effect, for selecting the half-cycle supplying most reliable and accurate tone parameters.",
"Such in phase synchronous processing implementing said SSP is used to provide said time domain recovery of only one or several such tones (sub-carriers), selected to facilitate said recovery of the referencing frame.",
"Such in phase processing assures maintaining said known or predictable processing delay between;",
"said reception of composite frame, and said detection signal of referencing frame boundary.",
"By evaluating amplitudes and/or phases of such recovered sinusoidal cycles or half-cycles, said received symbol boundary is detected when correlation between consecutive amplitudes and/or phases recovered falls down after maintaining a middle-symbol plateau, thus indicating the end of the received symbol frame.",
"Such in phase synchronous processing enables recovery of single half-cycles of said selected sub-carrier.",
"Therefore the phase of the end of last negative half-cycle recovered during such symbol frame, can be treated as the end boundary E B of this symbol frame.",
"Furthermore such ending phase enables detection of the received symbol boundary (time offset) with accuracy by ˜10× better than that of conventional solutions, when a data coding phase displacement C D of such selected tone is recovered and used to correct this ending phase, as it is explained below.",
"For a displacement code D C equal to 0, 1, 2 or 3, and for tone period T T , such coding displacement C D shall be calculated as: C D = D C T T 4 Plurality of half-cycles detected over symbol interval supplies a lot of redundant timing information about in phase processed tones (sub-carriers).",
"If another selected tone T2 is similarly in phase processed, than both tones coding displacements (C DT1 for T1, C DT2 for T2) can be calculated by analyzing time delay T KT1-KT2 measured between T1 cycle number K T1 and T2 cycle number K T2 .",
"Such displacement code can be calculated first as explained below: T KT 1 - KT 2 = K T 1 · T T 1 + C DT 1 - ( K T 2 · T T 2 + C D T 2 ) , consequent ly : D CT 1 T T 1 4 - D CT 2 T T 2 4 = T KT 1 - KT 2 - ( K T 1 · T T 1 + K T 2 · T T 2 ) = Δ , D CT 1 = D CT 2 T T 2 T T 1 + Δ 4 T T 1 wherein final D CT1 digit can be derived by substituting D CT2 =0, 1, 2, 3 into the above equation and by choosing for D CT1 this one of integers 0, 1, 2, 3 which is the closest to one of D CT1 values calculated with the above equation.",
"Knowing the D CT1 number said coding displacement of T1 can be calculated as: C DT 1 = D CT 1 T T 1 4 It shall be noticed that if Tone 1 frequency is by 4 times greater than that of Tone 2;",
"than the multiplier T T2 /T T1 =4 and consequently a time delay between a T1 cycle and closest to it T2 cycle supplies the value of the coding displacement C DT1 directly.",
"Furthermore in phase tones processing circuits implemented using said SSP techniques, define efficient and accurate registration of such time delays (between neighbor cycles of different tones), which can represent said direct C DT1 measurement.",
"RST comprises methods and systems enabling referencing frame phase recovery from OFDM data sub-carriers with ˜10× greater accuracy than that of conventional solutions without even requiring said preambles or pilot tones;",
"wherein such high accuracy phase recovery (HAPR) method comprises steps listed below: said in phase processing techniques are used for recovering amplitudes and phases of sinusoidal cycles or half-cycles of selected sub-carriers (tones), wherein such in phase processing assures maintaining said known or predictable processing delay between;",
"said reception of composite frame, and said detection signal of referencing frame boundary;",
"delay time between sinusoidal cycles of different selected tones is registered and used to recover data coding displacements occurring in the selected tones of the received composite frame;",
"an approximate symbol frame boundary is detected by evaluating amplitudes and/or phases of such recovered sinusoidal cycles or half-cycles, when correlation between consecutive amplitudes and/or phases recovered falls down after maintaining a middle-symbol plateau, thus indicating the end of the received symbol frame;",
"a phase of last cycle of such recovered sinusoidal tone is derived by analyzing amplitudes and/or phases of said sinusoidal cycles or half-cycles recovered before the end of symbol frame;",
"an accurate symbol boundary is derived by correcting such phase of last cycle with the data coding displacement.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 Shows an Open Ended Configuration of Software Controlled Clock Synchronizer.",
"FIG. 2 Shows Open Ended Configuration of SCCS with External Synchronization Mode FIG. 3 Shows Heterodyne Timing Configuration of SCCS enabling acceptance of very.",
"range of referencing clock frequencies.",
"FIG. 4 Shows Sequential Clocks Generator (SCG) and Output Selection Circuits (OSC) enabling high resolution selections of mutually overlapping sub-clocks.",
"FIG. 4A Shows Sequential Clocks Generator (SCG) and Return Selection Circuits (RSC), lowering output clock jitter FIG. 5 Shows Timing Control (TC) and Clocks Equalization (CE), which control timing of high frequency switching of synthesized clock FIG. 6 Shows Synchronous Sequential Phase Processor (SSPP), which performs programmable high-speed phase synthesis.",
"FIG. 7 Shows Timing Diagram of Phase Synthesizer.",
"FIG. 8 Shows Wave Capturing including Edge Regions (WCER), which enable continues capturing of a an oversampled high frequency waveform.",
"FIG. 9 Shows Sequential Clocks Generation for the NFED(SCG NFED), which provides mutually overlapping sub-clocks enabling high accuracy detection of noisy signal edges.",
"FIG. 10 Shows Noise Filtering Edge Detectors (NFED) FIG. 11 Shows Wave Form Screening &",
"Capturing (WFSC), which enables analysis of incoming noisy waveform facilitating adaptive noise filtering FIG. 12 Shows Timing Diagrams of the WFSC.",
"FIG. 13 Shows a block diagram of Inherently Stable Synchronization System.",
"Notes referring to FIG. 13 , are provided below: Boundary detection delay (Tbd) determines predictable part of referencing frame delay to OFDM composite frame.",
"Frequency offset (Fos) is not affected by the boundary detection delays Tbd for as long as Tbd remains constant.",
"In order to make up for the boundary detection delay, Phase Synthesizer (PS) positions Local Symbol Frame forward in time compared to Referencing Frame.",
"Frequency offset Fos derived using counted number of sampling clocks (Fcnt) and the nominal number (Fnom), can be measured with over 10× greater accuracy if it is measured over a reference frame interval over 10× longer.",
"FIG. 14 Shows a block diagram of Synchronization System with Improved Stability.",
"Notes referring to FIG. 14 , are provided below: Boundary detection delay (Tbd) determines predictable part of referencing frame delay to OFDM composite frame.",
"Frequency offset (Fos) is not affected by the boundary detection delays Tbd for as long as Tbd remains constant.",
"Time error (Terr) between local symbol frame and composite frame, amounts to boundary detection delay added to the phase error between reference frame and local symbol frame i.e. Ter=Tbd+(Trf−Is).",
"FIG. 15 Shows an Inherently Stable Frequency Locked Phase Synthesis system.",
"FIG. 16 Shows a similar FLPS system with its Frequency Detector utilizing local XTAL clock.",
"FIG. 17 Shows a similar FLPS with Improved Stability.",
"FIG. 18 Shows a similar FLPS but enabling more accurate generation of a synchronized clock.",
"DESCRIPTION OF THE PREFERRED EMBODIMENTS 1.",
"Phase Synthesizer The above mentioned first PS implementation is selected for the preferred embodiment, and it is shown in the FIG. 4 , FIG. 5 , FIG. 6 and FIG. 7 .",
"The PS comprises wave timing definition, which includes two major components downloaded to the PS from the PCU: basic less frequently changed phase adjustments, which can include both periodical adjustments and fractional adjustments, define more stable components of wave-form phase;",
"high frequency phase modulations, which can include both the periodical adjustments and the fractional adjustments, allow every leading edge phase and/or every falling edge phase to be modulated with a different modulation factor.",
"Said phase modulations are downloaded to the PS simultaneously in batches containing multiple different modulation factors, where every said batch refers to a series of consecutive wave edges.",
"The PS has internal selection circuits, which select and use consecutive modulation factors for modulating phases of consecutive edges.",
"In order to allow higher wave generation frequencies, 2 parallel processing circuits are implemented which use consecutive phase1/phase2 circuits for synthesizing phases of consecutive odd/even edges.",
"As it is shown in the FIG. 6 , said basic phase adjustments are loaded to the Periodical Number Buffer (PNB) and to the Fractional Number Buffer (FNB);",
"where they remain unchanged until PS internal Modulations Counter (MC) reaches MC=0 condition.",
"On the other hand, said modulation factors M1, M2-M6, M7 are shifted left, by one factor for every new edge, in the Phase Modulation Buffers (PMB1/PMB2) for providing consecutive modulation factor needed for a next edge in the left end of the PMB1/PMB2.",
"Such updated modulation factor is then added to the basic phase adjustments and resulting modulated phase adjustments are downloaded into the Periodical Number Registers (PNR1/PNR2) and into the Fractional Number Registers (FNR1/FNR2).",
"In order to synthesize an actual position of a new edge of the synthesized waveform;",
"said downloaded modulated phase adjustments need to be added to a current edge position, and the results of said addition are downloaded into the Periods Counters (PC1 or PC2) and into the Fractional Selection Register (FSR) The Sequential Clocks Generator (SCG) and Output Selection Circuits (OSC) are shown in the FIG. 4 and have been already explained in the Subsection “6. General Definition of Phase Synthesizer”",
"of the previous section.",
"The Clock Selection Register ½ (CSR1/CSR2) specifies a sub-clock which will be selected in a forthcoming Phase2/Phase1 cycle of the reference clock fsync.",
"In order to remain settled during a whole next cycle of the fsync, the CSR1/CSR2 registers are loaded by the early sub-clocks of the present Phase2/Phase1 cycle of the fsync.",
"The CSR1/CSR2 are loaded: with a current content of the Fractional Selection Register (FSR) (shown in FIG. 6 ), if the LD_C1 or LD_C2 (Load Counter 1 or Load Counter2) signal indicates that an end period of the present phase adjustment is indicated by the C2E or C1E (Counter 2 End or Counter 1 End) accordingly (see FIG. 2 and FIG. 3 );",
"with the binary value 2 S −1=R+1 which exceeds ranges of the 1 st Clock Selector (1CS) and the 2 nd Clock Selector (2CS) and results in none of selectors outputs being activated and none of sub-clocks being selected during a following phase cycle.",
"The Timing Control (TC) circuits are shown in FIG. 5 , the resulting Timing Diagram of Phase Synthesizer (TDPS) is shown in FIG. 7 , and TC operations are explained below.",
"The LD_C1 signal enables loading of the Period Counter 1 (PC1) with a number of periods which the previous stages of the Synchronous Sequential phase Processor (SSPP) have calculated for the current phase adjustment.",
"Said download deactivates/activates the C1E signal if a downloaded value is (bigger than 1)/(equal to 1) accordingly.",
"When said downloaded value is bigger than 1, the C1EN=1 enables decreasing the PC1 content by 1 at every leading edge of the Clk1.1 until the PC1=1 condition is achieved and is detected by the PC1-OVF Detector which signals it with the C1E=1 signal.",
"It shall be noticed that: when a fractional part of a phase adjustment calculated in said FSR reaches or exceeds a whole period of the fsync, the overflow bit FSR(OVF)=1 is activated and switches the PC1=1-OVF DETECTOR from said 1 detection mode to a 0 detection mode which prolongs current phase adjustment by 1 fsync period.",
"The phase 2 control circuit is driven by the C1E and by the LD_C1, and controls phase 2 operations with signals LD_C2, LD_RE2, LD_BU2;",
"as it is further explained below: The first C1E activation period generates the LD_C2 signal, and is followed by setting the LDR2_which terminates the LD_C2.",
"The LD_C2 signal;",
"enables loading of PC2 with a periods number for the next phase adjustment, enables loading of the FSR with a fractional adjustment for the next phase adjustment, and enables a downloading of the FSR to the CSR1 or to the CSR2.",
"The LDR2_FF=1 generates the leading edge of the LD_RE2 signal.",
"The LD_RE2 signal clocks in;",
"a new modified fractional adjustment to the Fractional Number Register 2 (FNR2), and a new modified periodical adjustment to the Periodical Number Register 2 (PNR2).",
"When the period number loaded by the LD_C2 is counted down to its end by the PC2, the C2E signal activates the LD_C1 similarly as the C1E has activated the LD_C2.",
"The LD_C1=1 resets both the C1E and the LDR2_FF in the next cycle;",
"The LDR2_FF=0 generates the leading edge of the LD_BU2 signal.",
"The LD_BU2 signal clocks in;",
"a previous PMB2 content shifted left by S+1 bits, or a new PM[M6,M4,M2,M0] content from the PCU when the Modulations Counter (MC) is decoded as MC=0.",
"The phase 1 control circuit is similarly driven by the C2E and by the LD_C2;",
"and similarly generates the LD_C1, LD_RE1, LD_BU1 signals for controlling phase1 operations.",
"The only differences in the phase 1 versus phase 2 operations, are specified below: The LD_BU1 signal clocks in a decreased by 1 value to the MC which is the modulo 4 counter.",
"The DECODER MC=0 generates the MC=0 signal which selects provided by the PCU;",
"the Periodical Number (PN)/the Fractional Number (FN)/the Phase Modifications (PM) to be loaded into the Periodical Number Buffer (PNB/the Fractional Number Buffer/the Phase Modifications Buffer 1(PMB1) by the leading edge of the LD_BU1.",
"The DECODER MC=1 generates the MC=1_INT interrupt signal to the PCU, which informs the PCU that all the above mentioned phase adjustment parameters have been already stored in the PS buffers and can be replaced by new phase adjustment parameters.",
"Heterodyne Timing Configuration FIG. 3 shows the heterodyne timing configuration (HTC) according to the preferred embodiment.",
"The HTC integrates both Digital PLLs (DPLLs) and Analog PLLs (APLLs) into a single CMOS ASIC, with the exception of the external VCXO which provides a stable clock (Fil_LocClk) having very low phase jitter.",
"Said APLL mode of the HTC is described below.",
"The Reference Selector (RFS) is programmed by the PCU to select one of the external reference clocks (Ext_RefClk).",
"Such selected external reference clock is applied to the reference input of the Analog Phase Detector (APD) which drives the Loop Filter of the VCXO which provides the stable low jitter output f_filter.",
"The Fil_OutClk;",
"drives the Output PLL (OUT_PLL), and is connected to the fsync/L input of the Return Clock Synthesizer (RET_PS) which is implemented with the PS embodiment described in the previous section.",
"The RET_PS synthesizes the RetClk, which is connected to the APD return input.",
"It shall be noticed that very wide ranges of the RET_PS frequency adjustments, enable the PCU to tune the RET_PS to any frequency which the selected external reference may have.",
"Said OUT_PLL generates the output reference clock (OutRef) which drives the Output Clocks Generator (OCG) which provides all the major HTC output clocks OutClk(T:1).",
"Since the OCG consists of frequency dividers having very tightly controlled and well matched propagation delays, all the OutClk(T:1) are phase aligned with the Fil_OutClk and between themselves.",
"The DPLL mode of the HTC is described below.",
"The Fil_OutClk signal is programmed to be selected by the RFS for the APD reference signal, and the RET_PS provides the APD return signal which is synthesized from the same Fil_OutClk signal.",
"One of the external reference waveforms (Ext_RefWfm) is selected by a selector controlled by the PCU for being processed by the NFED providing the filtered reference waveform (Fil_RefWfm), which is connected to the Time Stamp Decoder (TSD) and to the FPD1.",
"Local oscillator fixed output (LocOsc) is connected to the FPD2.",
"Both frame phase detectors FPD1/FPD2 shall use the high frequency sampling clock (SampClk) for accurate digital measurements of the PhaErr1 and the PhaErr2.",
"Said sampling clock is generated by the frequency multiplier OutRefxR from the OutRef generated by the OUT_PLL.",
"Since the OutClk(T:1) output clocks are phase aligned with the OUT_PLL ouput clock OutRef, and the sampling clock SampClk is phase aligned with the OutRef as well;",
"the SampClk is phase aligned with the HTC output clocks OutClk(T:1).",
"The FPD1 measures a phase error between the sampling clock SampClk and the Ext_RefWfm, as Δφ1=φ_samp−φ_wfm.",
"The FPD2 measures a phase error between the sampling clock SampClk and the LocOsc, as Δφ2=φ_samp−φ_osc.",
"The PCU reads the measured phase errors and uses the RET_PS to introduce digital phase displacements between the APD reference input and the APD return input which will drive the VCXO based PLL for providing required phase transfer functions between the Fil_OutClk and the Ext_RefWfm.",
"Since the Fil_OutClk drives the OUT_PLL which has much higher BW than the VCXO PLL and the OUT_PLL determines phase of the OutClk, the OutClk implements the same phase transfer function as the Fil_OutClk.",
"Based on the measurements of Δφ 1 and Δφ 2 , the PCU calculates said Periodical Numbers (PN), Fractional Numbers (FN) and Phase Modifications (PM) which need to be provided to the Return Phase Synthesizer (RET_PS);",
"in order to achieve a preprogrammed transfer function between the HTC output clocks and the selected DPLL reference clock Ext_RefWfm.",
"HTC free-run and hold-over modes use the above described DPLL mode configuration, as it is described below.",
"In the free-run mode;",
"the PCU uses the phase error measurements for calculating phase differences which need to be inserted via the RET_PS for providing said OutClk locking to the local oscillator LocOsc.",
"In the hold-over mode;",
"the PCU inserts phase differences via the RET_PS which cause the OutClk to maintain its last frequency displacement versus the LocOsc.",
"Noise Filtering Edge Detectors The preferred embodiment implements the above defined general components of the NFED and is shown in FIG. 8 , FIG. 9 and FIG. 10 .",
"The NFED comprises over-sampling and capturing of consecutive wave-form intervals in specifically dedicated consecutive wave registers, wherein odd intervals are written into the wave register 1WR and even intervals are written into the wave register 2WR.",
"Therefore incoming stream of samples is split into the two parallel processing phases (sometimes named as parallel synchronous pipelines).",
"The first processing phase begins in the wave register 1WR and the second begins in the register 2WR.",
"Such splitting into 2 parallel phases obviously doubles cycle time available in the sequential stages following the register 1WR and in the stages following the 2WR as well.",
"A sequential clock generation circuit (SCG) shows a method for splitting a steady stream of mutually overlapping sub-clocks spaced by a gate delay only into sub-sets of sub-clocks active during their dedicated phases only and non-active during all other phases.",
"Such subsets are obviously used for providing timing for their dedicated phases.",
"The wave register 1WR is further split into 2 parallel sub-phases and the 2WR is split into other 2 parallel sub-phases, for the purpose of quadrupling cycle time available in said sub-phases (see the FIG. 8 showing the wave registers 1WR, 2WR followed by the wave buffers 11WB, 12WB, 21WB, 22WB).",
"In order to provide all wave samples needed for the filtering edge detection along a whole wave buffer, the NFED includes rewriting: the end part 2WR(R:(R−M+1) of the wave register 2WR, into the front parts 11WB(M:1), 12WB(M:1) of the wave buffers 11WB, 12WB;",
"the end part 1WR(R:(R−M+1) of the wave register 1WR, into the front parts 21WB(M:1), 22WB(M:1) of the wave buffers 21WB, 22WB.",
"The preferred embodiment is based on the assumptions listed below: the wave registers 1WR and the 2WR are 15 bit registers (i.e. R=14);",
"the rising edge mask REM(M:0) and the falling edge mask FEM(M:0) are 8 bit registers (i.e. M=7) and the PCU loads the same masks equal to 00001111 to both mask registers;",
"the rising edge threshold RET is loaded with 0110 (6 decimal), and the falling edge threshold FET is loaded with 0010 (2 decimal);",
"The digital filter arithmometers 21DFA1/22DFA1/11DFA1/12DFA1 perform all the comparison functions, between the edge mask registers REM/FEM and the waveform buffers 21WB/22WB/11WB/12WB involving the edge threshold registers RET/FET, with the 3 basic operations which are further explained below.",
"The first operation is performed on all the waveform bits and involves the edge mask bits as it is specified below: For every waveform buffer consecutive bit WB k the surrounding bits WB k−4 , WB k−3 , WB k−2 , WB k−1 , WB k , WB k+1 , WB k+2 , WB k+3 are logically compared with the mask bits B 0 , B 1 , B 2 , B 3 , B 4 , B 5 , B 6 , B M and the resulting 8 bit binary expression BE k (7:0) is created as equal to;",
"BE k (0)=(WB k−4 =B 0 ), BE k (1)=(WB k−3 =B 1 ), BE k (2)=(WB k−2 =B 2 ) BE k (3)=(WB k−1 =B 3 ), BE k (4)=(WB k =B 4 ), BE k (5)=(WB k+1 =B 5 ) BE k (6)=(WB k+2 =B 6 ), BE k (7)=(WB k+3 =B 7 ).",
"The second operation adds arithmetically all the bits of the binary expression BE k (7:0) and the resulting edge proximity figure EPF k is calculated as equal to EPF k =BE k (0)+BE k (1)+BE k (2)+BE k (3)+BE k (4)+BE k (5)+BE k (6)+BE k (7) which shall amount to a 0-8 decimal number.",
"During the first and the second operations: all bits of any particular wave buffer have their specific edge proximity figures calculated at the same time during a cycle assigned for one of the arithmometers 21DFA1/22DFA1/11DFA1/12DFA1 attached to that buffer.",
"Since there are 15 bits in every wave buffer every such arithmometer consists of 15 parallel micro-arithmometers, wherein each such micro-arithmometer performs operation on an 8 bit edge mask and on 8 bit wave region.",
"Since this arithmometers perform the most intense processing, said quadrupling of cycle time by gradual splitting from the original 1 phase into the present 4 parallel phases was needed.",
"The third operation performs functions explained below: In order to carry the same level from the last bit of the previous phase DFR1 into the following bits of the present phase digital filter register2 (DFR2), the last bit DFR1(R) of the previous DFR1 is always rewritten into the carry bit DFR1(C) of the present DFR1 and is used by the digital filter arithmometer2 (DFRA2) to fill front bits of the DFR2 with the same level as the last bit of the previous phase DFR1.",
"The verification is made if the EPF k indicates a rising edge condition by exceeding the content of the rising edge threshold RET(T:0).",
"Consequent detection of the EPF k >RET=6 condition, sets to level=1 the corresponding DFR1 k bit of the DFR1 and all the remaining bits of the present DFR1 until a falling edge is detected as it is explained below.",
"The verification is made if the EPF k indicates a falling edge condition by being smaller than the content of the falling edge threshold FET(T:0).",
"Consequent detection of the EPF k <RET=2 condition, sets to level=0 the corresponding DFR1 k bit of the DFR1 and all the remaining bits of the present DFR1 unless a rising edge is detected as it explained above.",
"The digital filter arithmometers 21DFA2/22DFA2/11DFA2/12DFA2 perform;",
"the inter-phase continuation of filling front bits of the present phase register in accordance with the level set in the last bit of the previous phase, followed by said edge displacement which compensates for duty cycle distortions due to inter-symbol interference (ISI), etc.",
"The edge displacement comprises the 3 basic operations described below.",
"Any DFR1 rising edge, indicated by a level 0 to 1 transition, is shifted left by a number of bits specified by a content of the rising edge displacement register (RED(D:0)) loaded by the PCU in accordance with its filtering algorithms.",
"Any DFR1 falling edge, indicated by a level 1 to 0 transition, is shifted left by a number of bits specified by a content of the falling edge displacement register (FED(D:0)) loaded by the PCU in accordance with its filtering algorithms.",
"In order to propagate said displacement operations from the present phase to the previous phase;",
"the propagated sign of the edge bit (DFR2(Sp)) and the propagated bits (DFR2(Dp:0)), are calculated by the DFA2 and are written down into the DFR2 extension DFR2(Sp,Dp:0).",
"In order to propagate said displacement operations from the next phase DFR2 into end bits of the present phase digital filter register3 (DFR3);",
"the propagated sign of the edge bit and the propagated displaced bits DFR2(Sp,Dp:0) from the next phase, are used by the digital filter arithmometer3 (DFRA3) to fill end bits of the digital filter register3 (DFR3) with the correctly displaced bits propagated form the next phase to the present phase.",
"Wave-Form Screening and Capturing The wave-form screening and capturing (WFSC) of screened out intervals is performed by the circuits which are shown in FIG. 11 and the timing diagrams of the WFSC are shown FIG. 12 .",
"The WFSC allows the PCU to perform screening and capturing of the incoming signal, for timing intervals which correspond roughly to a period of a single data bit, based on a content of the wave buffers 11WB, 12WB, 21WB and 22WB.",
"The WFSC allows the PCU to screen signal quality of incoming wave form, by applying programmable screening functions using programmable data masks, as it is listed below: content of said wave buffers can be verified for compliance or non compliance with a mask provided by the PCU, based on verification functions and verification tolerances which are programmed by the PCU;",
"if any wave buffer verification detects preset by PCU screening out criteria to be met, the corresponding content of a wave buffer is captured and made available for PCU for further analysis;",
"in addition to the wave buffer capturing, a number of said screened out results will be counted and communicated to the PCU as well.",
"In addition to the above mentioned screening;",
"the WFSC allows also the PCU to select arbitrarily a content of any of the wave buffers during any particular time slot;",
"for being captured and made available for analysis by the PCU.",
"The above mentioned signal screening is implemented by the WFSC, as it is explained below.",
"The Mask Detection Arithmometrs (11MDA and 12MDA) for the WFSC are positioned similarly as the DFAs of the NFED.",
"The second stage uses the mask detection arithmometers 11MDA/12MDA for identifying wave-forms which are beyond usually acceptable range defined by the PCU.",
"The programmable control unit (PCU) determines logical and/or arithmetical processing which the 11MDA/12MDA shall perform, by pre-loading the detection control register (DCR) with a control code applied as the DCR(P:0) to the 11MDA/12MDA.",
"Additionally the PCU determines the mask DMR(R:0) which the captured data 11WB(R:0)/12WB(R:0) shall be processed against, by pre-loading the detection mask register (DMR).",
"The 11SEL signal equal to 1/0 selects;",
"the 11WB(R:0)/12WB(R:0) to be downloaded to the phase one detected data buffer (1DDB) by the clock 1Clk2 (see FIG. 11 and FIG. 12 ), if the 11DET/12DET indicate detection of a pre-selected mask by the mask detection arithmometer 11DMA/12DMA.",
"At the beginning of the next time frame, which has 128 phase1 cycles, the last captured 1DDB content is further downloaded to the phase1 data register (1DDR) by the clock signal 1Clk3/128.",
"Number of said mask detections is counted in the mask counter buffer (1MCB), as it is explained below: at the beginning of every time frame which has 128 phase1 cycles, the 1MCB is reset/preset to 0/1 if there isn't/is a mask detection for the first cycle of the frame which is signaled by the 1PHA/128ena=1;",
"the 1MCB is increased by 1/kept the same, if there is/isn't any mask detection during a particular phase1 cycle;",
"at the beginning of the next time frame, the 1MCB is downloaded to the phase1 mask counter register (1MCR) and the output of the 1MCB>0 decoder (MCB>0 DEC) is downloaded to the 1MCR(P) bit, by the 1Clk3/128.",
"Said 1DDR and 1MCR are read by the PCU, when the beginning of the next frame is communicated to the PCU by the phase1 128 th clock enable signal (1PHA/128ena) and the above mentioned 1MCR(P)=1 indicates that at least 1 detection of a pre-selected mask occurred during the previous frame.",
"Said PCU controlled capturing of a wave buffer content is implemented, as it is explained further below.",
"The sample number register (SNR) is loaded by the PCU: with a phase number defined as phase1/phase2 if the SNR(0) is set 0/1, and with a particular phase cycle number in a time frame defined by SNR(7:1) bits.",
"Since there are 2 phases with 128 cycles per time frame, SNR(7:0) bits define 1 of 256 sampling cycles for having its wave buffer captured and made available for a further analysis by the PCU.",
"Said SNR is downloaded into the phase1 sample number buffer (1SNB) at the beginning of a time frame by the first phase1 clock of the frame 1Clk2/128.",
"At the beginning of a time frame: the phase1 sample number counter (1SNC) is set to 0, since the 1PHA/128ena selects 0 to be loaded into the 1SNC by 1Clk2.",
"During every other cycle of the time frame: 1 is added to the SNC content, since the 1PHA/128ena is inactive during all the next cycles of the frame.",
"The 1SNC(7:1) and the 1SNB(7:1) are being compared by the logical comparator (Log.",
"Comp.), which produces the Eq=1 signal when their identity is detected.",
"Said Eq=1 enables the 1SNB(1)=0/1 to select the 11WB(R:0)/12WB(R:0) in the 3:1 selector (3:1 SEL), for capturing in the phase1 sampled data buffer (1SDB).",
"At the beginning of the next time frame, the output of the 3:1 SEL is additionally captured in the phase1 sampled data register (1SDR) by the signal 1Clk3/128.",
"Said 1SDR is read by the PCU, which is notified about availability of the requested sample by the signal 1PHA/128ena.",
"Receiver Synchronization Techniques Functional block diagram of inherently stable synchronization system is provided in FIG. 13 wherein recovery of OFDM receiver sampling clock Cs and local symbol frame F1s is shown.",
"More detailed implementation and partitioning of such system is shown in FIG. 15 .",
"Samples from an OFDM composite signal interval, long enough to comprise entire OFDM symbol, are processed by the Synchronous Sequential Processor (defined in Subsection 8 of SUMMARY OF THE INVENTION) which uses Cs as its reference clock (see FIG. 13 and FIG. 14 ).",
"Sub-clocks of such reference clock, driving such SSP used for OFDM processing, may not need to facilitate phase resolution matching single gate delay.",
"Therefore a conventional delay line, consisting of serially connected flip-flops driven by a frequency multiplier of the reference clock, can be sufficient to generate such lower resolution sub-clocks instead of using the delay line consisting of serially connected gates with all elaborate timing involved.",
"However independent of any delay line implementation, SSP architecture guaranties that all SSP micro-operations are performed in exactly predefined time windows within known time displacements to such reference clock.",
"Therefore SSP processing delay measured from entering last sample of an interval processed to producing the final result of such interval processing is totally predictable.",
"As specified therein, SSP includes real-time processing stages of incoming wave-form and a programmable computing unit (PCU) for supporting any adaptive signal processing dependent of previous micro-operations results or wave-form content.",
"SSP uses interrupts to acquire results of such PCU adaptive processing, while PCU produces such results in advance before they are needed (see also Subsection 8 of SUMMARY OF THE INVENTION).",
"Therefore SSP can use such results in predefined time windows synchronizing known sequence of said SSP micro-operations, while PCU accommodates all changes of processing time and/or algorithms.",
"Since such SSP is used to detect composite frame boundary, resulting boundary detection delay Tbd is known very accurately.",
"Despite such accurate Tbd, composite signal distortions due to channel interference and inherent problems of conventional methods for composite frame boundary detection, shall be expected to cause noticeable errors in boundary detection times which convey into receiver time offset errors.",
"However said predictable Tbd of the boundary detection signal Sbd (see FIG. 13 ) facilitates generation of the referencing frame Fr, re-timed by the sampling clock Cs.",
"Such Fr is applied to the digital frequency detector (DFD) which produces frequency offset estimate Fos by subtracting said expected nominal number of sampling clocks form the number of sampling clocks counted during said referencing frame interval.",
"As such DFD arrangement facilitates measuring frequency offset within referencing frame intervals corresponding to multiple periods of OFDM composite frame, such prolongation of frequency sensing intervals multiples accuracy of frequency offset measurements (see also time-diagrams and Note 4 in FIG. 13 ).",
"Such much more accurate frequency offset Fos applied to the frequency locked loop FLL, enables generation of said sampling clock with frequency by one order more accurate and thus prevents any inter-bin leaking endangering IDFT/IFFT processing of OFDM composite frame.",
"Such DFD/FLL configuration offers other significant advantages as well over phase locked loops PLL used conventionally in OFDM receivers.",
"Such configuration assures much faster frequency acquisition when connecting to new composite signal source, and avoids PLL instability when exposed to an unknown spectrum of phase noise caused by unpredictable channel interference and inaccuracy of conventional phase measurements methods.",
"Inherent stability is achieved by combining such stable sampling clock generation by FLL with the phase synthesizer PS (defined in Subsections 5 and 6 of SUMMARY OF THE INVENTION) working in the open ended configuration (shown in FIG. 13 and FIG. 15 ).",
"Such open ended PS configuration applies modifications of referencing frame phase with programmable phase steps defined by sub-clocks of sampling clock, wherein such sub-clocks are generated internally in PS from flip-flop based delay line driven by FreqDetClk produced by the frequency multiplier Samp-Clk×R of sampling clock Cs.",
"Such PS method (defined in the Subsections 5 and 6 mentioned above) uses the same SSP architecture as that used for the boundary detection discussed above.",
"Similarly sub-clocks driving such SSP do not need to facilitate phase resolution matching single gate delay.",
"Coincidentally sub-clocks used by PS for defining programmable phase steps applied to the local symbol frame do not need to provide phase resolution matching single gate delay either.",
"Therefore the same sub-clocks, generated by conventional flip-flop based delay line, can be used for both;",
"for driving said SSP utilized by SP, and for defining said programmable phase steps.",
"Such conventional delay line is used as consisting of serially connected flip-flops driven by the frequency multiplier Samp-Clk×R of the sampling clock wherein the sampling clock represents frequency multiplication of the local symbol frame (utilized as the reference clock by the SF_PS) by said nominal number Nn.",
"Consequently total frequency multiplication factor amounts to R×Nn.",
"PCU produces such steps number definition before it is requested by PS and places such steps number on its output PCU-OUT in response to PS interrupt MC_INT.",
"PCU shown in FIG. 15 receives;",
"the referencing frame Fr, the sampling clock Cs, the boundary delay time Tbd and said frequency offset Fos.",
"When synchronization acquisition is initialized, Fr presets an PCU internal Fr phase register to Nn-Tbd, wherein Nn is said nominal number expected for reference frame interval covering single OFDM symbol.",
"As such presetting of PCU internal Fr register provides said programmable presetting of numerical first edge specific for the FPD (see Subsection 7 of SUMMARY OF THE INVENTION), it utilizes such PCU function for upgrading this DPD to provide such FPD functionality.",
"At the same time the referencing frame prompts the PCU_OUT register to provide definition of such Nn-Tbd phase step, and prompts the symbol frame phase synthesizer SF_PS to generate PCU interrupt MC=1_INT and to implement such Nn-Tbd phase step.",
"Consequently the first edge of the Local Symbol Frame F1s is generated with the Nn-Tbd phase displacement to the initializing edge of Fr.",
"Dependent of specifics of a particular PS design;",
"such generation of F1s first edge displaced by Nn-Tbd phase step to the referencing frame edge, can include resetting the phase of frame generated previously by PS before such phase step is applied.",
"As PCU receives consecutive Fos values defining displacements of next detected Fr boundaries to consecutive expected boundaries, it keeps updating track record of previous Fos and said Fr phase register with such Fos values in order to maintain continues record of Fr phase changes and present status.",
"In order to avoid uncontrolled phase transients resulting from an accumulation of DFD digitization errors, only DFD design eliminating such digitization errors accumulation can be used (such DFD is defined in U.S. Pat. No. 6,864,672 by Bogdan).",
"Similarly PCU keeps also track record of previous phase steps defined to SF_PS and keeps updating its internal F1s phase register defining present phase of the local symbol frame.",
"Based on such data about Fr phase and F1s phase, PCU calculates a number of said phase steps which the referencing frame phase needs to be modified by, in order to implement a preprogrammed phase/frequency transient function between the local symbol frame and the referencing frame.",
"Such configuration enables accurate phase frequency control reducing phase noise and jitter.",
"In addition to the SF_PS, configuration shown in FIG. 15 uses another phase synthesizer FLL_PS placed in the return path of the analog phase locked loop APLL used to modify sampling clock frequency in order to minimize said frequency offset between the sampling clock and said composite signal clock.",
"Additionally to the data mentioned above, PCU keeps track of phase steps introduced into the sampling clock Cs via the FLL_PS.",
"Therefore PCU has all the data defining frequency and phase relations between the sampling clock Cs and the crystal oscillator clock LX_Clk, and between the LX_Clk and said composite frame clock outlined by the referencing frame clock.",
"Similar configuration shown in FIG. 16 utilizes LX_Clk, instead of the sampling clock, for producing said Freq.",
"DetClk.",
"Therefore PCU scales said nominal number Nn, proportionally to frequency offset between the LX_Clk and the composite clock outlined by the Fr, before utilizing such Nn for measuring Fos with the DFD referenced by the LX_Clk.",
"Synchronization System with improved stability shown in FIG. 14 and FIG. 17 , includes: using the additional DPD for measuring time offset (phase error) Trf-1s between the referencing frame Fr and the symbol frame F1s, instead of relying entirely on PCU subroutines explained above;",
"such Trf-1s is supplied to PCU which uses it to maintain close control of such time offset (phase error) by defining appropriate phase steps to the symbol frame synthesizer SF_PS.",
"Such synchronization system can facilitate even closer control of such phase offset, while it implicates lesser stability improvements and simpler phase frequency control less efficient in reducing phase/frequency transients.",
"High Accuracy FLPS shown in FIG. 18 represents high performance synchronization system which will be needed in future high speed wireless/wireline OFDM and mobile receivers, including next generations of ADSL, WiFi or WiMAX.",
"Such system facilitates multiplying low frequency (down to 30 kHz) of XTAL oscillator (LX_Clk) by very high factor (up to 50 000), in order to utilize very inexpensive low frequency crystal cuts for producing highly stable local oscillator clock.",
"Such frequency multiplier utilizes DFD1 for measuring frequency error XTALos between the XTAL oscillator clock (LX_Clk) and the sampling clock Cs represented by the FreqDetClk, wherein the frequency multiplication factor R shall be lower than 10 in order to avoid stability problems in SOC PLL implementations.",
"PCU reads the frequency error XTALos and produces sequence of PCU-OUT signals supplied to the frequency locked loop phase synthesizer (FLL_PS) located in the reference path of VCXO based analog PLL having very low bandwidth (for example 0.1-1 kHz).",
"Such PCU_OUT signals cause said FLL_PS to insert phase errors which drive said analog PLL into producing sampling clock Cs maintaining pre-programmed frequency relation to the LX_Clk.",
"Since such PCU-OUT signals represent sequence of small phase steps applied with frequency by several orders higher than that of analog PLL bandwidth, resulting Cs jitter shall be very low.",
"Consequently, such system multiplies low frequency of highly accurate inexpensive local XTAL oscillator (LX_Clk), in order to produce sampling clock frequency with accuracy much better than 1 ppm.",
"Such system utilizes SCCS concept of multiplying low frequency of highly accurate inexpensive local XTAL oscillator, in order to produce sampling clock frequency with accuracy much better than 1 ppm (see Subsections 1, 2 and 3 of SUMMARY OF THE INVENTION).",
"This system combines all the advanced features, explained above for the FLPS shown in FIG. 15 , combined with such highly efficient frequency multiplication method.",
"CONCLUSION In view of the above description of the invention and associated drawings, other modifications and variations will now become apparent to those skilled in the art based on the teachings contained herein.",
"Such other modifications and variations fall within the scope and spirit of the present invention."
] |
TECHNICAL FIELD
[0001] The present invention relates to a base station apparatus, a terminal apparatus, a radio communication apparatus and a transmission method in a multimedia broadcast and multicast service (MBMS) system.
BACKGROUND ART
[0002] MBMS is a point-to-multipoint (p-t-m) transmission service in which a base station apparatus (hereinafter simply referred to as “base station”) transmits information data of, for example, multimedia broadcasting and broadcast service to a plurality of terminal apparatuses (hereinafter simply referred to as “terminal”). In MBMS, a base station performs transmission to a plurality of terminals by assigning the same data block to the same radio resource, so that, compared to unicast transmission for performing transmission by assigning a plurality of data blocks to a plurality of radio resources by point-to-point (p-t-p), MBMS has a feature that makes it possible to improve the efficiency of use of radio resources.
[0003] MBMS is stipulated by 3rd Generation Partnership Project (3GPP), a standards organization. In MBMS, the scheme for transmitting the same data block from a single base station is called “single-cell transmission,” and the scheme for performing transmission from a plurality of base stations is called “multi-cell transmission.”
[0004] Non-Patent Literature 1 stipulates applying hybrid-automatic repeat request (HARQ) as retransmission control in the single-cell transmission MBMS, as is the case with unicast transmission.
[0005] A terminal that receives an MBMS data block returns acknowledgement or negative acknowledgement (ACK or NACK) to a base station, depending on whether or not the terminal is able to decode the data block correctly. The base station retransmits the MBMS data block in response to which a NACK is detected.
[0006] According to the technique described in Non-Patent Literature 1, a plurality of terminals return an ACK or a NACK separately, so that the efficiency of use of radio resources in an uplink (uplink channel) lowers as the number of terminals increases.
[0007] Further, as the number of NACKs increases, frequent retransmission occurs, so that the efficiency of use of radio resources in a downlink (downlink channel) lowers. For example, when the frequency of NACKs at a terminal receiving an MBMS service at the cell edge is high, retransmission is performed to all terminals receiving the same service.
[0008] To solve the problem of the above-described technique, Non-Patent Literature 2 suggests the following methods of returning an ACK or a NACK.
[0009] An ACK is not returned, and only a NACK is returned using on-off keying (OOK).
[0010] A plurality of terminals return a NACK using the same radio resources in an uplink.
[0011] NACKs from a plurality of terminals are added to the same radio resources and are transmitted to a base station. The base station receives the NACKs that are added for a plurality of terminals, and determines whether or not to perform retransmission according to those NACKs. For example, the base station compares the power of NACKs against a threshold value, and according to the result of the comparison with the threshold value, determines whether or not to perform retransmission.
CITATION LIST
Non-Patent Literature
NPL 1
[0000]
3GPP TS 36.300 V8.7.0 (2008-12)
NPL 2
[0000]
Nokia, Nokia Siemens Networks, “MBMS single cell p-t-m related control signaling,” R1-080929, 3GPP TSG RAN WG1 Meeting #52
SUMMARY OF INVENTION
Technical Problem
[0014] However, the scheme described in Non-Patent Literature 2 has the following problem.
[0015] In the case where a base station determines whether or not to perform retransmission according to the comparison with a threshold value of power of NACKs that are added for a plurality of terminals, when NACKs are transmitted by the minority number of terminals, there is a likelihood that a condition where the data block that could not be decoded by the minority number of terminals is not retransmitted (hereinafter referred to as “Minority NACK”) occurs. NACK occurs stochastically. Therefore, minority NACK can occur in all terminals.
[0016] Generally speaking, because transmission information data is divided into a plurality of data blocks to be transmitted, minority NACK occurs, and when that data block is not retransmitted, the terminal cannot decode the transmission information data and has difficulty receiving the service.
[0017] As described above, because the scheme described in Non-Patent Literature 2 is a majority rule-based retransmission scheme, the data block that could not be decoded by the terminal is not retransmitted to that terminal for which minority NACK occurs, lowering service quality in that terminal.
[0018] It is therefore an object of the present invention to provide a base station apparatus, a terminal apparatus, a radio communication system, and a transmission method that can provide all terminals reporting a retransmission request with a chance of retransmission, and alleviate decrease of the efficiency of downlink channel radio resources due to retransmission.
Solution to Problem
[0019] A base station apparatus according to the present invention employs a configuration to be a base station apparatus for transmitting multi-carrier data and/or broadcast data to a plurality of terminal apparatuses per data block at the same time, the base station apparatus including: a reception section that receives a retransmission request signal from each of the plurality of terminal apparatuses; an encoding and modulation section that encodes and modulates transmission data contained in data blocks that are different from each other, according to the received retransmission request signal, and outputs a plurality of data blocks for retransmission; a multiplexing section that multiplexes the plurality of data blocks for retransmission and outputs a multiplexed block; and an arrangement section that arranges the multiplexed block in a time slot for retransmission.
[0020] A terminal apparatus according to the present invention employs a configuration to include a reception section that receives a symbol sequence transmitted per data block at the same time from a base station apparatus; a slot demultiplexing section that demultiplexes a multiplexed block arranged in a time slot for retransmission, from the symbol sequence; a block demultiplexing section that demultiplexes the multiplexed block into a plurality of data blocks and outputs a data block for retransmission; a demodulation and decoding section that demodulates and decodes the data block for retransmission and outputs decoded data; an error detection section that detects whether an error of the decoded data is present or not present; and a transmission section that transmits a retransmission request signal according to a result of the error detection.
[0021] A radio communication system according to the present invention employs a configuration to include a base station apparatus that transmits multi-carrier data and/or broadcast data per data block to a plurality of terminal apparatuses at the same time and includes: a reception section that receives a retransmission request signal from each of the plurality of terminal apparatuses; an encoding and modulation section that encodes and modulates transmission data contained in data blocks that are different from each other, according to the received retransmission request signal, and outputs a plurality of data blocks for retransmission; a multiplexing section that multiplexes the plurality of data blocks for retransmission and outputs a multiplexed block; and an arrangement section that arranges the multiplexed block in a time slot for retransmission; and a terminal apparatus that includes: a reception section that receives a symbol sequence transmitted per data block at the same time from the base station apparatus; a slot demultiplexing section that demultiplexes the multiplexed block arranged in the time slot for retransmission, from the symbol sequence; a block demultiplexing section that demultiplexes the multiplexed block into a plurality of data blocks, and outputs a data block for retransmission; a demodulation and decoding section that demodulates and decodes the data block for retransmission, and outputs decoded data; an error detection section that detects whether an error of the decoded data is present or not present; and a transmission section that transmits the retransmission request signal according to a result of the error detection.
[0022] A transmission method according to the present invention employs a configuration to be a transmission method of transmitting multi-carrier data and/or broadcast data per data block to a plurality of terminal apparatuses at the same time, the method including the steps of: receiving a retransmission request signal from each of the plurality of terminal apparatuses; encoding and modulating transmission data contained in data blocks that are different from each other, according to the received retransmission request signal, and outputting a plurality of data blocks for retransmission; multiplexing the plurality of data blocks for retransmission, and outputting a multiplexed block; and arranging the multiplexed block in a time slot for retransmission.
Advantageous Effects of Invention
[0023] According to the present invention, it is possible to provide all terminals reporting a retransmission request with a chance of retransmission, and alleviate decrease of the efficiency of downlink channel radio resources due to retransmission.
BRIEF DESCRIPTION OF DRAWINGS
[0024] FIG. 1 shows a principal-part configuration of a transmitting base station according to Embodiment 1 of the present invention;
[0025] FIG. 2 shows a principal-part configuration of a receiving terminal according to Embodiment 1;
[0026] FIG. 3 shows an example of an arrangement of multiplexed blocks according to Embodiment 1;
[0027] FIG. 4 shows an example of an arrangement of multiplexed blocks according to Embodiment 1;
[0028] FIG. 5 shows yet another example of an arrangement of multiplexed blocks according to Embodiment 1;
[0029] FIG. 6 shows a principal-part configuration of a transmitting base station according to Embodiment 2 of the present invention;
[0030] FIG. 7 shows a principal-part configuration of a receiving terminal according to Embodiment 2;
[0031] FIG. 8 shows an example of an arrangement of multiplexed blocks according to Embodiment 2;
[0032] FIG. 9 shows a principal-part configuration of a transmitting base station according to Embodiment 3 of the present invention;
[0033] FIG. 10 shows a principal-part configuration of a receiving terminal according to Embodiment 3; and
[0034] FIG. 11 shows an example of an arrangement of multiplexed blocks according to Embodiment 3.
DESCRIPTION OF EMBODIMENTS
[0035] Now, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Embodiment I
[0036] FIG. 1 shows a principal-part configuration of transmitting base station 100 according to the present embodiment.
[0037] Division section 101 receives as input transmission data and divides the transmission data into a plurality of blocks. Then, division section 101 outputs the plurality of data blocks obtained to encoding and modulation section 102 and encoding and modulation section 110 .
[0038] Encoding and modulation section 102 includes encoding section 103 and modulation section 104 , and encoding section 103 performs encoding processing on a data block containing transmission data for the initial transmission that is output from division section 101 . Further, modulation section 104 modulates the encoded data output from encoding section 103 to generate a data block for the initial, transmission. Then, modulation section 104 outputs the generated data block for the initial transmission to arrangement section 114 .
[0039] Radio reception section 106 receives a control signal (feedback information) transmitted from a receiving terminal, via antenna 105 , performs reception processing, such as down conversion and A/D conversion, on that control signal, and outputs the reception-processed control signal to demodulation section 107 . This control signal contains a response signal (ACK or NACK) and a data block number that are sent by feedback from the receiving terminal. According to the present embodiment, a response signal (ACK or NACK) is reported to base station 100 , per data block.
[0040] Demodulation section 107 demodulates the control signal and outputs the demodulated control signal to retransmission request detection section 108 .
[0041] From the control signal input from demodulation section 107 , retransmission request detection section 108 detects the response signal (ACK or NACK), which is reported from each terminal, per data block. Then, retransmission request detection section 108 outputs information about the detected response signal and data block number to retransmission control section 109 .
[0042] Retransmission control section 109 controls retransmission of the data block based on the response signal and the data block number input from retransmission request detection section 108 . Specifically, retransmission control section 109 outputs the data block number in response to which a NACK is reported, which is input from retransmission request detection section 108 , to encoding and modulation section 110 . Further, retransmission control section 109 outputs the number of data block numbers in response to which a NACK is reported in a predetermined time, as multiplexing number N, to multiplexing section 113 and modulation section 115 . Further, retransmission control section 109 outputs information about the data block number contained in the multiplexed block to modulation section 115 . Further, in the case where arbitrarily setting a predetermined time for detecting the number of data block numbers in response to which a NACK is reported, retransmission control section 109 outputs information about that predetermined time to modulation section 115 .
[0043] Encoding and modulation section 110 includes encoding section 111 and modulation section 112 , and encoding section 111 maintains the transmission data output from division section 101 , per data block, and performs encoding processing on the transmission data contained in the data block number reported from retransmission control section 109 . Further, modulation section 112 modulates the encoded data output from encoding section 111 to generate a data block for retransmission. Then, modulation section 112 outputs the generated data block for retransmission to multiplexing section 113 .
[0044] Multiplexing section 113 multiplexes N data blocks for retransmission based on multiplexing number N input from retransmission control section 109 , to generate a multiplexed block. For the multiplexing method, multiplexing section 113 uses time division multiplexing, frequency division multiplexing, or code division multiplexing. Multiplexing section 113 outputs the generated multiplexed block to arrangement section 114 .
[0045] Arrangement section 114 arranges the data block for the initial transmission and the multiplexed block in the time slots, and outputs the arranged data block for the initial transmission and multiplexed block (symbol sequence) to data and control signal multiplexing section 116 . Specifically, arrangement section 114 provides a time slot for retransmission per predetermined period, and arranges a multiplexed block in that time slot for retransmission. The predetermined period is set based on the predetermined time for detecting the number of data block numbers in response to which a NACK is reported, in the above-described retransmission control section 109 . The method of arrangement in arrangement section 114 will be described later. Arrangement section 114 outputs the arranged symbol sequence to data and control signal multiplexing section 116 .
[0046] Modulation section 115 modulates multiplexing number N, the control information including information about the data block number contained in the multiplexed block and information about the period in which the time slot for retransmission is provided, and outputs the modulated control information to data and control signal multiplexing section 116 .
[0047] Data and control signal multiplexing section 116 multiplexes the symbol sequence arranged in each time slot (data block for the initial transmission and multiplexed block) with the control information input from modulation section 115 , in arrangement section 114 , and outputs the multiplexed signal to radio transmission section 117 .
[0048] Radio transmission section 117 performs transmission processing, such as DIA conversion, amplification, and up-conversion, on the signal input from data and control signal multiplexing section 116 , and transmits the transmission-processed signal to receiving terminals at the same time, via antenna 105 .
[0049] FIG. 2 shows a principal-part configuration of receiving terminal 200 according to the present embodiment.
[0050] Radio reception section 202 receives the signal transmitted from transmitting base station 100 via antenna 201 , and performs reception processing, such as down conversion and AID conversion, on that signal. Then, radio reception section 202 outputs the reception-processed signal to multiplexing information detection section 203 and time slot demultiplexing section 204 .
[0051] Multiplexing information detection section 203 extracts information about multiplexing number N of the data block for retransmission that is multiplexed with a multiplexed block, from the reception signal, and outputs information about extracted multiplexing number N and the data block number of the data block for retransmission, to block demultiplexing section 206 . Further, upon detecting information about the period in which a time slot for retransmission is provided, from a reception signal, multiplexing information detection section 203 outputs the detected information about the period in which a time slot for retransmission is provided, to time slot demultiplexing section 204 .
[0052] Time slot demultiplexing section 204 demultiplexes the data block for the initial transmission that is arranged in the time slot for the initial transmission and the multiplexed block arranged in the time slot for retransmission, from the reception-processed signal. Then, time slot demultiplexing section 204 outputs the data block for the initial transmission to demodulation section 205 , and outputs the data block for retransmission to block demultiplexing section 206 .
[0053] Demodulation section 205 demodulates the data block for the initial transmission input from time slot demultiplexing section 204 , and outputs the demodulated data block to decoding section 208 .
[0054] Block demultiplexing section 206 demultiplexes the multiplexed block arranged in the time slot for retransmission that is input from time slot demultiplexing section 204 into N data blocks for retransmission, based on multiplexing number N input from multiplexing information detection section 203 , by associating that multiplexed block with the multiplexing method in multiplexing section 113 of base station 100 .
[0055] Further, block demultiplexing section 206 extracts the data block number from which an error is detected, from the control signal input from error detection section 209 (described later), and, out of the demultiplexed data blocks for retransmission, outputs the data block for retransmission corresponding to the data block number from which an error is detected, to demodulation section 207 .
[0056] Demodulation section 207 demodulates the data block for retransmission input from block demultiplexing section 206 (i.e. data block from which an error is detected in the past in error detection section 209 ), and outputs the demodulated data block to decoding section 208 .
[0057] Decoding section 208 decodes each of the data blocks input from demodulation section 205 and demodulation section 207 . For the decoding method, preferably, decoding section 208 performs, for example, HARQ processing per data block. That is, when decoding a data block, decoding processing is performed by synthesizing the data block that is received previously and from which an error is detected in error detection section 209 and the data block for retransmission that is received this time, so that it is possible to improve the encoding gain. Decoding section 208 outputs each of the decoded data blocks to error detection section 209 .
[0058] Error detection section 209 performs error detection on the data block input from decoding section 208 . Then, error detection section 209 generates a response signal per data block according the result of the error detection (whether an error is present or not present). When the error detection result is “error is present,” error detection section 209 generates a response signal containing a NACK and the data block number of the data block from which an error is detected. On the other hand, when the error detection result is “error is not present,” error detection section 209 generates a response signal containing an ACK and the data block number of the data block from which an error is not detected. Error detection section 209 outputs the control signal containing a NACK or an ACK and the data block number, to block demultiplexing section 206 and modulation section 210 .
[0059] Modulation section 210 modulates the control signal input from error detection section 209 , and outputs the modulated control signal to radio transmission section 211 .
[0060] Radio transmission section 211 performs transmission processing, such as D/A conversion, amplification, and up-conversion, on the control signal, and transmits the transmission-processed control signal to transmitting base station 100 via antenna 201 .
[0061] Next, the method of arranging time slots for retransmission according to the present embodiment will be described with reference to FIG. 3 .
[0062] FIG. 3 shows an example of correspondence between data block numbers (# 1 to # 6 ) arranged in respective time slots (T 1 to T 8 ) and response signals reported from four terminals (UE # 1 to UE # 4 , UE: user equipment) to respective data blocks.
[0063] In FIG. 3 , time slots T 1 to T 3 and T 5 to T 7 are time slots for the initial transmission, and time slots T 4 and T 8 are time slots for retransmission, and FIG. 3 shows a case where time slots for retransmission are provided per four time slots. In this case, retransmission control section 109 sets the number of data block numbers in response to which a MACK is reported within a predetermined time of three time slots, as multiplexing number N.
[0064] For example, as shown in FIG. 3 , when NACKs are reported from UEs # 2 , # 3 , and # 4 in response to data block # 1 that is transmitted in time slot for the initial transmission T 1 , a NACK is reported from UE # 4 in response to data block # 2 that is transmitted in time slot for the initial transmission T 2 , and ACKs are reported from all UEs # 1 to # 4 in response to data block # 3 that is transmitted in time slot for the initial transmission T 3 , retransmission control section 109 sets multiplexing number N as two and outputs the multiplexing number of two to multiplexing section 113 .
[0065] Multiplexing section 113 multiplexes data blocks # 1 and # 2 to generate a multiplexed block, and arrangement section 114 provides a time slot for retransmission in time slot T 4 and arranges the multiplexed block in that time slot T 4 . With reference to FIG. 3 , the multiplexed block arranged in time slot T 4 shows a case where data blocks for retransmission of data blocks # 1 and # 2 , are frequency multiplexed in multiplexing section 113 , and the multiplexed block arranged in time slot T 8 shows a case where data blocks for retransmission of data blocks # 4 , # 5 , and # 6 , are frequency multiplexed in multiplexing section 113 .
[0066] As described above, according to the present embodiment, arrangement section 114 provides a time slot per predetermined period, and multiplexes and combines data blocks in response to which a NACK is sent by feedback to arrange the data blocks in that time slot for retransmission. By this means, it is possible to ensure retransmission to all terminals that have sent a NACK by feedback, that is, in the case of FIG. 3 , UE # 2 to UE # 4 . Further, data blocks for retransmission are arranged to be multiplexed in one time slot, it is possible to reduce the loss of the efficiency of frequency of downlink channel radio resources due to retransmission.
[0067] The arrangement pattern of time slots for the initial transmission and time slots for retransmission (hereinafter referred to as “time slot arrangement pattern”) is not limited to the pattern of FIG. 3 , and it is possible to adopt any arrangement patterns as long as time slots for retransmission are provided periodically. In this ease, when terminal 200 knows the time slot arrangement pattern in advance, base station 100 can only report multiplexing number N of the multiplexed blocks to be arranged in the time slot for retransmission.
[0068] Further, it is possible to configure retransmission control section 109 to determine the encoding rate and the modulation level for generating retransmission data blocks according to multiplexing number N in multiplexing section 113 , and output the determined encoding rate and modulation level to encoding and modulation section 110 . For example, in the case shown in FIG. 3 , because the number of data blocks for retransmission to be multiplexed in time slot T 4 is two, retransmission control section 109 determines the encoding rates and modulation levels of data block # 1 and data block # 2 so that half of the frequency resources are assigned to each block. By this means, it is possible to efficiently use frequency resources that can be used in a time slot for retransmission and generate multiplexed blocks at the same time.
[0069] Further, retransmission control section 109 can assign more radio resources to transmission data of a data block having a larger number of NACKs reported, that is, transmission data of a data block having a larger number of NACKs reported from different terminals, out of data blocks to be multiplexed. For example, in the case where NACKs are reported from three UEs (# 2 , # 3 , and # 4 ) in response to data block # 1 , and a NACK is reported from one UE (# 4 ) in response to data block # 2 , the proportion of radio resources to be assigned to data block # 1 is set greater than the proportion of radio resources to be assigned to data block # 2 , among radio resources in the time slot for retransmission (see FIG. 4 ). By this means, by assigning more radio resources in the time slot for retransmission to a data block having more retransmission requests, it is possible to improve the encoding gain or the modulation gain of the data block having many retransmission requests and prevent a retransmission request from being reported again. In other words, retransmission control section 109 can lower the encoding rate or the modulation level of transmission data of a data block having a larger number of NACKs reported, that is, transmission data of a data block having a larger number of NACKs reported from different terminals, out of data blocks to be multiplexed.
[0070] Although a case in which data blocks for retransmission are frequency multiplexed is shown in FIG. 3 and FIG. 4 , it is possible to time multiplex a data block for retransmission, as shown in FIG. 5 , and it is also possible to code multiplex a data block for retransmission.
Embodiment 2
[0071] A case has been described with Embodiment 1 where a time slot for retransmission is provided per predetermined period, and data blocks in response to which a NACK is sent by feedback are multiplexed and combined to be arranged in that time slot for retransmission.
[0072] A case will be described with the present embodiment where, when the number of different data blocks in response to which a NACK is sent by feedback reaches predetermined number M, a time slot for retransmission is provided, and M data blocks in response to which a NACK is sent by feedback is multiplexed and combined to be arranged in that time slot for retransmission.
[0073] FIG. 6 shows a principal-part configuration of a transmitting base station according to the present embodiment. In the base station of FIG. 6 according to the present embodiment, parts that are the same as in FIG. 1 will be assigned the same reference numerals as in FIG. 1 and overlapping explanations will be omitted. Compared to base station 100 of FIG. 1 , base station 100 A of FIG. 6 includes retransmission control section 109 A, multiplexing section 113 A, arrangement section 114 A, and modulation section 115 A, instead of retransmission control section 109 , multiplexing section 113 , arrangement section 114 , and modulation section 115 .
[0074] Retransmission control section 109 A controls retransmission of a data block based on the response signal and the data block number that are input from retransmission request detection section 108 . Specifically, retransmission control section 109 A outputs the data block number in response to which a NACK is reported, which is input from retransmission request detection section 108 , to encoding and modulation section 110 . Further, retransmission control section 109 A counts the number of different data block numbers in response to which a NACK is reported, and when the number of different data block numbers in response to which a NACK is reported reaches predetermined number M, outputs a control signal for reporting that the number of different data block numbers in response to which a NACK is reported has reached predetermined number M, to multiplexing section 113 A, arrangement section 114 A, and modulation section 115 A. Further, in the case where base station 100 A sets the value of predetermined number M arbitrarily, retransmission control section 109 A outputs information about predetermined number M to modulation section 115 A.
[0075] Upon receiving the control signal from retransmission control section 109 A, multiplexing section 113 A multiplexes M data blocks for retransmission to generate a multiplexed block. For the multiplexing method, multiplexing section 113 A uses time division multiplexing, frequency division multiplexing, or code division multiplexing. Multiplexing section 113 A outputs the generated multiplexed block to arrangement section 114 A.
[0076] Arrangement section 114 A arranges the data blocks for the initial transmission and the multiplexed block in time slots, and outputs the arranged data blocks for the initial transmission and multiplexed block, to data and control signal multiplexing section 116 . Specifically, upon receiving the control signal to report that the number of different block numbers in response to which a NACK is reported has reached predetermined number M from retransmission control section 109 A, arrangement section 114 A provides a time slot for retransmission, and arranges the multiplexed block in that time slot for retransmission. The method of arrangement in arrangement section 114 A will be described later.
[0077] Modulation section 115 A modulates the control information including information about the data block number contained in the multiplexed block and information about the position of the time slot for retransmission, and outputs the modulated control information to data and control signal multiplexing section 116 . Further, when receiving as input information about predetermined number M from retransmission control section 109 A, modulation section 115 A performs modulation by including information about predetermined number M in the control information.
[0078] FIG. 7 shows a principal-part configuration of a receiving terminal according to the present embodiment. In the terminal of FIG. 7 according to the present embodiment, parts that are the same as in FIG. 2 will be assigned the same reference numerals as in FIG. 2 and overlapping explanations will be omitted. Compared to terminal 200 of FIG. 2 , terminal 200 A of FIG. 7 is configured to include multiplexing information detection section 203 A, time slot demultiplexing section 204 A, and block demultiplexing section 206 A, instead of multiplexing information detection section 203 , time slot demultiplexing section 204 , and block demultiplexing section 206 .
[0079] Multiplexing information detection section 203 A detects the position of the time slot for retransmission in which a multiplexed block is arranged, from the control information contained in the reception signal, and outputs information about the detected position of the time slot for retransmission, to time slot demultiplexing section 204 A. Further, in the case where information about predetermined number M is contained in the control information, multiplexing information detection section 203 A outputs the information about predetermined number M to block demultiplexing section 206 A.
[0080] Time slot demultiplexing section 204 A demultiplexes the data block for the initial transmission that is arranged in the time slot for the initial transmission and the multiplexed block arranged in the time slot for retransmission, from the reception-processed signal, using information of the position of the time slot for retransmission reported from multiplexing information detection section 203 A. Then, time slot demultiplexing section 204 A outputs the data block for the initial transmission to demodulation section 205 , and outputs the data block for retransmission to block demultiplexing section 206 A.
[0081] Block demultiplexing section 206 A demultiplexes the multiplexed block arranged in the time slot for retransmission that is input from time slot demultiplexing section 204 A, into M data blocks for retransmission, based on predetermined multiplexing number M, by associating the multiplexed block with the multiplexing method in multiplexing section 113 A of base station 100 A. Block demultiplexing section 206 A outputs the demultiplexed data block for retransmission to demodulation section 207 .
[0082] Next, the method of arranging time slots for retransmission according to the present embodiment will be described with reference to FIG. 8 .
[0083] FIG. 8 shows an example of correspondence between data blocks arranged in respective time slots (T 1 to T 8 ) and response signals reported from four terminals (UE # 1 to UE # 4 ) in response to respective data block numbers (# 1 to # 6 ).
[0084] According to the present embodiment, arrangement section 114 A provides a time slot for retransmission, when the number of different blocks in response to which a NACK is reported reaches predetermined number M.
[0085] In FIG. 8 , time slots TI, T 2 , T 4 to T 6 , and T 8 are time slots for the initial transmission, and time slots T 3 and T 7 are time slots for retransmission, and FIG. 8 shows a case where time slots for retransmission are provided when the number of different blocks in response to which a NACK is reported is two.
[0086] Specifically, in the case where NACKs are reported from UEs # 2 , # 3 , and # 4 in response to data block for the initial transmission # 1 that is transmitted in time slot T 1 , and a NACK is reported from UE # 4 in response to data block for the initial transmission # 2 that is transmitted in time slot T 2 , retransmission control section 109 A outputs a control signal for reporting that the number of different data block numbers in response to which a NACK is reported becomes a predetermined number of two, to multiplexing section 113 A.
[0087] Multiplexing section 113 A multiplexes data blocks # 1 and # 2 to generate a multiplexed block, and arrangement section 114 A provides a time slot for retransmission in time slot T 3 and arranges the multiplexed block in that time slot T 3 .
[0088] As described above, according to the present embodiment, in the case where the number of different data blocks in response to which a NACK is reported reaches predetermined number M, arrangement section 114 A provides a time slot for retransmission, and multiplexes and combines the data blocks in response to which a NACK is sent by feedback to arrange the multiplexed and combined data block in that time slot for retransmission. By this means, it is possible to ensure retransmission to all terminals that have sent a NACK by feedback, that is, in the case of FIG. 8 , UE # 2 to UE # 4 . Further, data blocks for retransmission are arranged to be multiplexed in one time slot, it is possible to reduce the loss of the efficiency of frequency of downlink channel radio resources due to retransmission. Further, it is possible to set a limit to the number of data blocks to be multiplexed, so that, by setting predetermined number M as an appropriate value, it is possible to prevent the condition where radio resources in data blocks for retransmission is divided into a large numbers and radio resources to be assigned to each data block for retransmission becomes extremely scarce, making it possible to ensure appropriate radio resources for a data block for retransmission.
[0089] The multiplexing number of a data block for retransmission is not limited to two, and it is possible to provide base station 100 A and terminal 200 A with multiplexing number M in advance, or it is possible to report multiplexing number M from base station 100 A to terminal 200 A. cl Embodiment 3
[0090] A method of assigning radio resources to a data block for retransmission that is to be arranged by being multiplexed in a time slot for retransmission, will be described with the present embodiment.
[0091] FIG. 9 shows a principal-part configuration of transmitting base station 300 according to the present embodiment. In base station 300 of FIG. 9 according to the present embodiment, parts that are the same as in FIG. 1 will be assigned the same reference numerals as in FIG. 1 and overlapping explanations will be omitted. Compared to base station 100 of
[0092] FIG. 1 , base station 300 of FIG. 9 is configured to include retransmission control section 302 and modulation section 303 , instead of retransmission control section 109 and modulation section 115 , and add channel quality indicator (CQI) extraction section 301 .
[0093] CQI extraction section 301 extracts channel quality indicator (CQI) of each terminal from demodulated control information, and outputs information about the extracted CQI to retransmission control section 302 .
[0094] Retransmission control section 302 , in the same way as retransmission control section 109 , controls retransmission of a data block based on the response signal and the data block number input from retransmission request detection section 108 . Further, retransmission control section 302 determines the encoding rate and the modulation level for generating a data block for retransmission and radio resources to which that data block for retransmission is assigned, so as to assign the data block for retransmission of the data block in response to which a NACK is reported, to radio resources having better channel quality of a terminal that has returned that NACK, based on the channel quality indicator (CQI) of the terminal that has reported the NACK. Retransmission control section 302 outputs information about the determined encoding rate and modulation level to encoding and modulation section 110 , and outputs information about the radio resources to which a data block for retransmission is to be assigned, to multiplexing section 113 and modulation section 303 .
[0095] In addition to the operation of modulation section 115 , modulation section 303 performs modulation by including information about radio resources to which a data block for retransmission is to be assigned in the control information.
[0096] FIG. 10 shows a principal-part configuration of a transmitting terminal according to the present embodiment. In terminal 400 of FIG. 10 according to the present embodiment, parts that are the same as in FIG. 2 will be assigned the same reference numerals as in FIG. 2 and overlapping explanations will be omitted. Compared to terminal 200 of FIG. 2 , terminal 400 of FIG. 10 is configured to include modulation section 402 instead of modulation section 210 , and add channel condition detection section 401 .
[0097] Channel condition detection section 401 detects the condition of a channel using the control signal transmitted from base station 300 , and outputs the detected channel condition to modulation section 402 as a channel quality indicator (CQI).
[0098] Modulation section 402 modulates the control signal input from error detection section 209 and the channel quality indicator (CQI) input from channel condition detection section 401 , and outputs the modulated control signal to radio transmission section 211 .
[0099] Next, a method of assigning radio resources to a data block for retransmission according to the present embodiment, will be described with reference to FIG. 11 .
[0100] FIG. 11 shows an example of correspondence between data blocks arranged in respective time slots (T 1 to T 8 ) and response signals reported from four terminals (UE # 1 to UE # 4 ) in response to respective data block numbers (# 1 to # 6 ).
[0101] In FIG. 11 , time slots T 1 to T 3 and T 5 to T 7 are time slots for the initial transmission, and time slots T 4 and T 8 are time slots for retransmission, and FIG. 10 , in the same way as FIG. 3 , shows a case where time slots for retransmission are provided per predetermined period, per four time slots.
[0102] In this case, in the same way as in FIG. 3 , consider a case where NACKs are reported from UEs # 2 , # 3 , and # 4 in response to data block # 1 that is transmitted in time slot for the initial transmission T 1 , and a NACK is reported from UE # 4 in response to data block # 2 that is transmitted in time slot for the initial transmission T 2 , and ACKs are reported from all UEs # 1 to # 4 in response to data block # 3 that is transmitted in time slot for the initial transmission T 3 .
[0103] Retransmission control section 302 determines the encoding rate and the modulation level for generating a data block for retransmission and radio resources for assigning that data block for retransmission, so as to assign the data block for retransmission of the data block in response to which a NACK is reported, to radio resources having good channel quality of a terminal that has returned that NACK, based on the channel quality indicator (CQI) of the terminal that reports the NACK in the time slot interposed between the time slots for retransmission.
[0104] For example, in the case where, in time slots T 1 to T 3 , the channel quality of UEs # 2 and # 3 that have reported a NACK in response to data block # 1 is better as the frequency decreases, and the channel quality of UE # 4 that has reported a NACK in response to data block # 2 is better as the frequency increases, retransmission control section 302 assigns data block # 1 to the low-frequency area, and assigns data block # 2 to the high-frequency area, in the radio resources of the time slot for retransmission (see FIG. 11 ), and outputs information about radio resources to which the data block for retransmission will be assigned, to multiplexing section 113 .
[0105] Further, in the case where, in time slots T 5 to T 7 , the channel quality of UE # 3 that has reported a NACK in response to data block # 5 is better nearer the center of the frequency, and the channel quality of UE # 4 that has reported a NACK in response to data block # 6 is better as the frequency decreases, retransmission control section 302 assigns data block # 5 to the center area of frequency, assigns data block # 6 to the low-frequency area, and assigns the remaining data block # 4 to the high-frequency area, in the radio resources of the time slots for retransmission (see FIG. 11 ), and outputs information about radio resources to which the data block for retransmission will be assigned, to multiplexing section 113 .
[0106] The example shown in FIG. 11 is a case where the proportion of radio resources to assign is made larger, for transmission data of a data block having a larger number of NACKs reported, that is, transmission data of a data block having a larger number of NACKs reported from different terminals, out of data blocks for retransmission to be multiplexed.
[0107] As described above, according to the present embodiment, retransmission control section 302 determines radio resources to which data blocks for retransmission are assigned, based on the channel quality of a terminal that has reported a retransmission request. By this means, multiplexing section 113 can assign a data block for retransmission to radio resources having good channel quality of a terminal that has reported a retransmission request, so that it is possible to prevent a retransmission request from being reported again and improve the efficiency of retransmission.
[0108] Although a method of assigning radio resources to a data block for retransmission to be multiplexed and arranged in the time slot for retransmission that is described in Embodiment 1, has been described with the above embodiment, it is also possible to apply the radio resource assignment method described in the present embodiment to a data block for retransmission to be multiplexed and arranged in the time slot for retransmission that is described in Embodiment 2.
[0109] Further, the above descriptions are examples of preferable embodiments of the present invention and the scope of the present invention is not limited to these.
[0110] Further, in the above descriptions, a data block refers to a unit for encoding and decoding, and it is possible to substitute “transport block,” “code ward,” or “packet,” for example, for “data block.” Further, in the above descriptions, “a time slot” refers to a transmission time unit, and it is possible to substitute “subframe” or “frame,” for example for “time slot.”
[0111] The disclosure of Japanese Patent Application No. 2009-130869, filed on May 29, 2009, including the specification, drawings and abstract, is incorporated herein by reference in its entirety.
INDUSTRIAL APPLICABILITY
[0112] The present invention is useful, for example, for a base station apparatus, a terminal apparatus, a radio communication system, and a transmission method in an MBMS system.
REFERENCE SIGNS LIST
[0000]
100 , 100 A, 300 Base station
101 Division section
102 , 110 Encoding and modulation section
103 , 111 Encoding section
104 , 112 , 115 , 115 A, 210 , 303 , 402 Modulation section
106 , 202 Radio reception section
105 , 201 Antenna
107 , 205 , 207 Demodulation section
108 Retransmission request detection section
109 , 109 A, 302 Retransmission control section
113 , 113 A Multiplexing section
114 , 114 A Arrangement section
116 Data and control signal multiplexing section
117 , 211 Radio transmission section
200 , 200 A, 400 Terminal
203 , 203 A Multiplexing information detection section
204 , 204 A Time slot demultiplexing section
206 , 206 A Block demultiplexing section
208 Decoding section
209 Error detection section | Disclosed is a base station device that reduces efficiency drops in downlink radio resources due to retransmission while giving all terminals that have sent a retransmission request a retransmission opportunity. In the base station device ( 100 ), an allocator unit ( 114 ) creates a retransmission time slot for each fixed cycle, and data blocks having received a NACK are multiplexed and allocated to said retransmission time slots. By this means, retransmission can be guaranteed for all terminals (for UE# 2 -UE# 4 in FIG. 3 ) that have sent a NACK. Further, because the retransmission data blocks are multiplexed and allocated to one time slot, frequency efficiency losses of downlink radio resources due to retransmission can be reduced. | Identify the most important claim in the given context and summarize it | [
"TECHNICAL FIELD [0001] The present invention relates to a base station apparatus, a terminal apparatus, a radio communication apparatus and a transmission method in a multimedia broadcast and multicast service (MBMS) system.",
"BACKGROUND ART [0002] MBMS is a point-to-multipoint (p-t-m) transmission service in which a base station apparatus (hereinafter simply referred to as “base station”) transmits information data of, for example, multimedia broadcasting and broadcast service to a plurality of terminal apparatuses (hereinafter simply referred to as “terminal”).",
"In MBMS, a base station performs transmission to a plurality of terminals by assigning the same data block to the same radio resource, so that, compared to unicast transmission for performing transmission by assigning a plurality of data blocks to a plurality of radio resources by point-to-point (p-t-p), MBMS has a feature that makes it possible to improve the efficiency of use of radio resources.",
"[0003] MBMS is stipulated by 3rd Generation Partnership Project (3GPP), a standards organization.",
"In MBMS, the scheme for transmitting the same data block from a single base station is called “single-cell transmission,” and the scheme for performing transmission from a plurality of base stations is called “multi-cell transmission.”",
"[0004] Non-Patent Literature 1 stipulates applying hybrid-automatic repeat request (HARQ) as retransmission control in the single-cell transmission MBMS, as is the case with unicast transmission.",
"[0005] A terminal that receives an MBMS data block returns acknowledgement or negative acknowledgement (ACK or NACK) to a base station, depending on whether or not the terminal is able to decode the data block correctly.",
"The base station retransmits the MBMS data block in response to which a NACK is detected.",
"[0006] According to the technique described in Non-Patent Literature 1, a plurality of terminals return an ACK or a NACK separately, so that the efficiency of use of radio resources in an uplink (uplink channel) lowers as the number of terminals increases.",
"[0007] Further, as the number of NACKs increases, frequent retransmission occurs, so that the efficiency of use of radio resources in a downlink (downlink channel) lowers.",
"For example, when the frequency of NACKs at a terminal receiving an MBMS service at the cell edge is high, retransmission is performed to all terminals receiving the same service.",
"[0008] To solve the problem of the above-described technique, Non-Patent Literature 2 suggests the following methods of returning an ACK or a NACK.",
"[0009] An ACK is not returned, and only a NACK is returned using on-off keying (OOK).",
"[0010] A plurality of terminals return a NACK using the same radio resources in an uplink.",
"[0011] NACKs from a plurality of terminals are added to the same radio resources and are transmitted to a base station.",
"The base station receives the NACKs that are added for a plurality of terminals, and determines whether or not to perform retransmission according to those NACKs.",
"For example, the base station compares the power of NACKs against a threshold value, and according to the result of the comparison with the threshold value, determines whether or not to perform retransmission.",
"CITATION LIST Non-Patent Literature NPL 1 [0000] 3GPP TS 36.300 V8.7[.",
"].0 (2008-12) NPL 2 [0000] Nokia, Nokia Siemens Networks, “MBMS single cell p-t-m related control signaling,” R1-080929, 3GPP TSG RAN WG1 Meeting #52 SUMMARY OF INVENTION Technical Problem [0014] However, the scheme described in Non-Patent Literature 2 has the following problem.",
"[0015] In the case where a base station determines whether or not to perform retransmission according to the comparison with a threshold value of power of NACKs that are added for a plurality of terminals, when NACKs are transmitted by the minority number of terminals, there is a likelihood that a condition where the data block that could not be decoded by the minority number of terminals is not retransmitted (hereinafter referred to as “Minority NACK”) occurs.",
"NACK occurs stochastically.",
"Therefore, minority NACK can occur in all terminals.",
"[0016] Generally speaking, because transmission information data is divided into a plurality of data blocks to be transmitted, minority NACK occurs, and when that data block is not retransmitted, the terminal cannot decode the transmission information data and has difficulty receiving the service.",
"[0017] As described above, because the scheme described in Non-Patent Literature 2 is a majority rule-based retransmission scheme, the data block that could not be decoded by the terminal is not retransmitted to that terminal for which minority NACK occurs, lowering service quality in that terminal.",
"[0018] It is therefore an object of the present invention to provide a base station apparatus, a terminal apparatus, a radio communication system, and a transmission method that can provide all terminals reporting a retransmission request with a chance of retransmission, and alleviate decrease of the efficiency of downlink channel radio resources due to retransmission.",
"Solution to Problem [0019] A base station apparatus according to the present invention employs a configuration to be a base station apparatus for transmitting multi-carrier data and/or broadcast data to a plurality of terminal apparatuses per data block at the same time, the base station apparatus including: a reception section that receives a retransmission request signal from each of the plurality of terminal apparatuses;",
"an encoding and modulation section that encodes and modulates transmission data contained in data blocks that are different from each other, according to the received retransmission request signal, and outputs a plurality of data blocks for retransmission;",
"a multiplexing section that multiplexes the plurality of data blocks for retransmission and outputs a multiplexed block;",
"and an arrangement section that arranges the multiplexed block in a time slot for retransmission.",
"[0020] A terminal apparatus according to the present invention employs a configuration to include a reception section that receives a symbol sequence transmitted per data block at the same time from a base station apparatus;",
"a slot demultiplexing section that demultiplexes a multiplexed block arranged in a time slot for retransmission, from the symbol sequence;",
"a block demultiplexing section that demultiplexes the multiplexed block into a plurality of data blocks and outputs a data block for retransmission;",
"a demodulation and decoding section that demodulates and decodes the data block for retransmission and outputs decoded data;",
"an error detection section that detects whether an error of the decoded data is present or not present;",
"and a transmission section that transmits a retransmission request signal according to a result of the error detection.",
"[0021] A radio communication system according to the present invention employs a configuration to include a base station apparatus that transmits multi-carrier data and/or broadcast data per data block to a plurality of terminal apparatuses at the same time and includes: a reception section that receives a retransmission request signal from each of the plurality of terminal apparatuses;",
"an encoding and modulation section that encodes and modulates transmission data contained in data blocks that are different from each other, according to the received retransmission request signal, and outputs a plurality of data blocks for retransmission;",
"a multiplexing section that multiplexes the plurality of data blocks for retransmission and outputs a multiplexed block;",
"and an arrangement section that arranges the multiplexed block in a time slot for retransmission;",
"and a terminal apparatus that includes: a reception section that receives a symbol sequence transmitted per data block at the same time from the base station apparatus;",
"a slot demultiplexing section that demultiplexes the multiplexed block arranged in the time slot for retransmission, from the symbol sequence;",
"a block demultiplexing section that demultiplexes the multiplexed block into a plurality of data blocks, and outputs a data block for retransmission;",
"a demodulation and decoding section that demodulates and decodes the data block for retransmission, and outputs decoded data;",
"an error detection section that detects whether an error of the decoded data is present or not present;",
"and a transmission section that transmits the retransmission request signal according to a result of the error detection.",
"[0022] A transmission method according to the present invention employs a configuration to be a transmission method of transmitting multi-carrier data and/or broadcast data per data block to a plurality of terminal apparatuses at the same time, the method including the steps of: receiving a retransmission request signal from each of the plurality of terminal apparatuses;",
"encoding and modulating transmission data contained in data blocks that are different from each other, according to the received retransmission request signal, and outputting a plurality of data blocks for retransmission;",
"multiplexing the plurality of data blocks for retransmission, and outputting a multiplexed block;",
"and arranging the multiplexed block in a time slot for retransmission.",
"Advantageous Effects of Invention [0023] According to the present invention, it is possible to provide all terminals reporting a retransmission request with a chance of retransmission, and alleviate decrease of the efficiency of downlink channel radio resources due to retransmission.",
"BRIEF DESCRIPTION OF DRAWINGS [0024] FIG. 1 shows a principal-part configuration of a transmitting base station according to Embodiment 1 of the present invention;",
"[0025] FIG. 2 shows a principal-part configuration of a receiving terminal according to Embodiment 1;",
"[0026] FIG. 3 shows an example of an arrangement of multiplexed blocks according to Embodiment 1;",
"[0027] FIG. 4 shows an example of an arrangement of multiplexed blocks according to Embodiment 1;",
"[0028] FIG. 5 shows yet another example of an arrangement of multiplexed blocks according to Embodiment 1;",
"[0029] FIG. 6 shows a principal-part configuration of a transmitting base station according to Embodiment 2 of the present invention;",
"[0030] FIG. 7 shows a principal-part configuration of a receiving terminal according to Embodiment 2;",
"[0031] FIG. 8 shows an example of an arrangement of multiplexed blocks according to Embodiment 2;",
"[0032] FIG. 9 shows a principal-part configuration of a transmitting base station according to Embodiment 3 of the present invention;",
"[0033] FIG. 10 shows a principal-part configuration of a receiving terminal according to Embodiment 3;",
"and [0034] FIG. 11 shows an example of an arrangement of multiplexed blocks according to Embodiment 3.",
"DESCRIPTION OF EMBODIMENTS [0035] Now, embodiments of the present invention will be described in detail with reference to the accompanying drawings.",
"Embodiment I [0036] FIG. 1 shows a principal-part configuration of transmitting base station 100 according to the present embodiment.",
"[0037] Division section 101 receives as input transmission data and divides the transmission data into a plurality of blocks.",
"Then, division section 101 outputs the plurality of data blocks obtained to encoding and modulation section 102 and encoding and modulation section 110 .",
"[0038] Encoding and modulation section 102 includes encoding section 103 and modulation section 104 , and encoding section 103 performs encoding processing on a data block containing transmission data for the initial transmission that is output from division section 101 .",
"Further, modulation section 104 modulates the encoded data output from encoding section 103 to generate a data block for the initial, transmission.",
"Then, modulation section 104 outputs the generated data block for the initial transmission to arrangement section 114 .",
"[0039] Radio reception section 106 receives a control signal (feedback information) transmitted from a receiving terminal, via antenna 105 , performs reception processing, such as down conversion and A/D conversion, on that control signal, and outputs the reception-processed control signal to demodulation section 107 .",
"This control signal contains a response signal (ACK or NACK) and a data block number that are sent by feedback from the receiving terminal.",
"According to the present embodiment, a response signal (ACK or NACK) is reported to base station 100 , per data block.",
"[0040] Demodulation section 107 demodulates the control signal and outputs the demodulated control signal to retransmission request detection section 108 .",
"[0041] From the control signal input from demodulation section 107 , retransmission request detection section 108 detects the response signal (ACK or NACK), which is reported from each terminal, per data block.",
"Then, retransmission request detection section 108 outputs information about the detected response signal and data block number to retransmission control section 109 .",
"[0042] Retransmission control section 109 controls retransmission of the data block based on the response signal and the data block number input from retransmission request detection section 108 .",
"Specifically, retransmission control section 109 outputs the data block number in response to which a NACK is reported, which is input from retransmission request detection section 108 , to encoding and modulation section 110 .",
"Further, retransmission control section 109 outputs the number of data block numbers in response to which a NACK is reported in a predetermined time, as multiplexing number N, to multiplexing section 113 and modulation section 115 .",
"Further, retransmission control section 109 outputs information about the data block number contained in the multiplexed block to modulation section 115 .",
"Further, in the case where arbitrarily setting a predetermined time for detecting the number of data block numbers in response to which a NACK is reported, retransmission control section 109 outputs information about that predetermined time to modulation section 115 .",
"[0043] Encoding and modulation section 110 includes encoding section 111 and modulation section 112 , and encoding section 111 maintains the transmission data output from division section 101 , per data block, and performs encoding processing on the transmission data contained in the data block number reported from retransmission control section 109 .",
"Further, modulation section 112 modulates the encoded data output from encoding section 111 to generate a data block for retransmission.",
"Then, modulation section 112 outputs the generated data block for retransmission to multiplexing section 113 .",
"[0044] Multiplexing section 113 multiplexes N data blocks for retransmission based on multiplexing number N input from retransmission control section 109 , to generate a multiplexed block.",
"For the multiplexing method, multiplexing section 113 uses time division multiplexing, frequency division multiplexing, or code division multiplexing.",
"Multiplexing section 113 outputs the generated multiplexed block to arrangement section 114 .",
"[0045] Arrangement section 114 arranges the data block for the initial transmission and the multiplexed block in the time slots, and outputs the arranged data block for the initial transmission and multiplexed block (symbol sequence) to data and control signal multiplexing section 116 .",
"Specifically, arrangement section 114 provides a time slot for retransmission per predetermined period, and arranges a multiplexed block in that time slot for retransmission.",
"The predetermined period is set based on the predetermined time for detecting the number of data block numbers in response to which a NACK is reported, in the above-described retransmission control section 109 .",
"The method of arrangement in arrangement section 114 will be described later.",
"Arrangement section 114 outputs the arranged symbol sequence to data and control signal multiplexing section 116 .",
"[0046] Modulation section 115 modulates multiplexing number N, the control information including information about the data block number contained in the multiplexed block and information about the period in which the time slot for retransmission is provided, and outputs the modulated control information to data and control signal multiplexing section 116 .",
"[0047] Data and control signal multiplexing section 116 multiplexes the symbol sequence arranged in each time slot (data block for the initial transmission and multiplexed block) with the control information input from modulation section 115 , in arrangement section 114 , and outputs the multiplexed signal to radio transmission section 117 .",
"[0048] Radio transmission section 117 performs transmission processing, such as DIA conversion, amplification, and up-conversion, on the signal input from data and control signal multiplexing section 116 , and transmits the transmission-processed signal to receiving terminals at the same time, via antenna 105 .",
"[0049] FIG. 2 shows a principal-part configuration of receiving terminal 200 according to the present embodiment.",
"[0050] Radio reception section 202 receives the signal transmitted from transmitting base station 100 via antenna 201 , and performs reception processing, such as down conversion and AID conversion, on that signal.",
"Then, radio reception section 202 outputs the reception-processed signal to multiplexing information detection section 203 and time slot demultiplexing section 204 .",
"[0051] Multiplexing information detection section 203 extracts information about multiplexing number N of the data block for retransmission that is multiplexed with a multiplexed block, from the reception signal, and outputs information about extracted multiplexing number N and the data block number of the data block for retransmission, to block demultiplexing section 206 .",
"Further, upon detecting information about the period in which a time slot for retransmission is provided, from a reception signal, multiplexing information detection section 203 outputs the detected information about the period in which a time slot for retransmission is provided, to time slot demultiplexing section 204 .",
"[0052] Time slot demultiplexing section 204 demultiplexes the data block for the initial transmission that is arranged in the time slot for the initial transmission and the multiplexed block arranged in the time slot for retransmission, from the reception-processed signal.",
"Then, time slot demultiplexing section 204 outputs the data block for the initial transmission to demodulation section 205 , and outputs the data block for retransmission to block demultiplexing section 206 .",
"[0053] Demodulation section 205 demodulates the data block for the initial transmission input from time slot demultiplexing section 204 , and outputs the demodulated data block to decoding section 208 .",
"[0054] Block demultiplexing section 206 demultiplexes the multiplexed block arranged in the time slot for retransmission that is input from time slot demultiplexing section 204 into N data blocks for retransmission, based on multiplexing number N input from multiplexing information detection section 203 , by associating that multiplexed block with the multiplexing method in multiplexing section 113 of base station 100 .",
"[0055] Further, block demultiplexing section 206 extracts the data block number from which an error is detected, from the control signal input from error detection section 209 (described later), and, out of the demultiplexed data blocks for retransmission, outputs the data block for retransmission corresponding to the data block number from which an error is detected, to demodulation section 207 .",
"[0056] Demodulation section 207 demodulates the data block for retransmission input from block demultiplexing section 206 (i.e. data block from which an error is detected in the past in error detection section 209 ), and outputs the demodulated data block to decoding section 208 .",
"[0057] Decoding section 208 decodes each of the data blocks input from demodulation section 205 and demodulation section 207 .",
"For the decoding method, preferably, decoding section 208 performs, for example, HARQ processing per data block.",
"That is, when decoding a data block, decoding processing is performed by synthesizing the data block that is received previously and from which an error is detected in error detection section 209 and the data block for retransmission that is received this time, so that it is possible to improve the encoding gain.",
"Decoding section 208 outputs each of the decoded data blocks to error detection section 209 .",
"[0058] Error detection section 209 performs error detection on the data block input from decoding section 208 .",
"Then, error detection section 209 generates a response signal per data block according the result of the error detection (whether an error is present or not present).",
"When the error detection result is “error is present,” error detection section 209 generates a response signal containing a NACK and the data block number of the data block from which an error is detected.",
"On the other hand, when the error detection result is “error is not present,” error detection section 209 generates a response signal containing an ACK and the data block number of the data block from which an error is not detected.",
"Error detection section 209 outputs the control signal containing a NACK or an ACK and the data block number, to block demultiplexing section 206 and modulation section 210 .",
"[0059] Modulation section 210 modulates the control signal input from error detection section 209 , and outputs the modulated control signal to radio transmission section 211 .",
"[0060] Radio transmission section 211 performs transmission processing, such as D/A conversion, amplification, and up-conversion, on the control signal, and transmits the transmission-processed control signal to transmitting base station 100 via antenna 201 .",
"[0061] Next, the method of arranging time slots for retransmission according to the present embodiment will be described with reference to FIG. 3 .",
"[0062] FIG. 3 shows an example of correspondence between data block numbers (# 1 to # 6 ) arranged in respective time slots (T 1 to T 8 ) and response signals reported from four terminals (UE # 1 to UE # 4 , UE: user equipment) to respective data blocks.",
"[0063] In FIG. 3 , time slots T 1 to T 3 and T 5 to T 7 are time slots for the initial transmission, and time slots T 4 and T 8 are time slots for retransmission, and FIG. 3 shows a case where time slots for retransmission are provided per four time slots.",
"In this case, retransmission control section 109 sets the number of data block numbers in response to which a MACK is reported within a predetermined time of three time slots, as multiplexing number N. [0064] For example, as shown in FIG. 3 , when NACKs are reported from UEs # 2 , # 3 , and # 4 in response to data block # 1 that is transmitted in time slot for the initial transmission T 1 , a NACK is reported from UE # 4 in response to data block # 2 that is transmitted in time slot for the initial transmission T 2 , and ACKs are reported from all UEs # 1 to # 4 in response to data block # 3 that is transmitted in time slot for the initial transmission T 3 , retransmission control section 109 sets multiplexing number N as two and outputs the multiplexing number of two to multiplexing section 113 .",
"[0065] Multiplexing section 113 multiplexes data blocks # 1 and # 2 to generate a multiplexed block, and arrangement section 114 provides a time slot for retransmission in time slot T 4 and arranges the multiplexed block in that time slot T 4 .",
"With reference to FIG. 3 , the multiplexed block arranged in time slot T 4 shows a case where data blocks for retransmission of data blocks # 1 and # 2 , are frequency multiplexed in multiplexing section 113 , and the multiplexed block arranged in time slot T 8 shows a case where data blocks for retransmission of data blocks # 4 , # 5 , and # 6 , are frequency multiplexed in multiplexing section 113 .",
"[0066] As described above, according to the present embodiment, arrangement section 114 provides a time slot per predetermined period, and multiplexes and combines data blocks in response to which a NACK is sent by feedback to arrange the data blocks in that time slot for retransmission.",
"By this means, it is possible to ensure retransmission to all terminals that have sent a NACK by feedback, that is, in the case of FIG. 3 , UE # 2 to UE # 4 .",
"Further, data blocks for retransmission are arranged to be multiplexed in one time slot, it is possible to reduce the loss of the efficiency of frequency of downlink channel radio resources due to retransmission.",
"[0067] The arrangement pattern of time slots for the initial transmission and time slots for retransmission (hereinafter referred to as “time slot arrangement pattern”) is not limited to the pattern of FIG. 3 , and it is possible to adopt any arrangement patterns as long as time slots for retransmission are provided periodically.",
"In this ease, when terminal 200 knows the time slot arrangement pattern in advance, base station 100 can only report multiplexing number N of the multiplexed blocks to be arranged in the time slot for retransmission.",
"[0068] Further, it is possible to configure retransmission control section 109 to determine the encoding rate and the modulation level for generating retransmission data blocks according to multiplexing number N in multiplexing section 113 , and output the determined encoding rate and modulation level to encoding and modulation section 110 .",
"For example, in the case shown in FIG. 3 , because the number of data blocks for retransmission to be multiplexed in time slot T 4 is two, retransmission control section 109 determines the encoding rates and modulation levels of data block # 1 and data block # 2 so that half of the frequency resources are assigned to each block.",
"By this means, it is possible to efficiently use frequency resources that can be used in a time slot for retransmission and generate multiplexed blocks at the same time.",
"[0069] Further, retransmission control section 109 can assign more radio resources to transmission data of a data block having a larger number of NACKs reported, that is, transmission data of a data block having a larger number of NACKs reported from different terminals, out of data blocks to be multiplexed.",
"For example, in the case where NACKs are reported from three UEs (# 2 , # 3 , and # 4 ) in response to data block # 1 , and a NACK is reported from one UE (# 4 ) in response to data block # 2 , the proportion of radio resources to be assigned to data block # 1 is set greater than the proportion of radio resources to be assigned to data block # 2 , among radio resources in the time slot for retransmission (see FIG. 4 ).",
"By this means, by assigning more radio resources in the time slot for retransmission to a data block having more retransmission requests, it is possible to improve the encoding gain or the modulation gain of the data block having many retransmission requests and prevent a retransmission request from being reported again.",
"In other words, retransmission control section 109 can lower the encoding rate or the modulation level of transmission data of a data block having a larger number of NACKs reported, that is, transmission data of a data block having a larger number of NACKs reported from different terminals, out of data blocks to be multiplexed.",
"[0070] Although a case in which data blocks for retransmission are frequency multiplexed is shown in FIG. 3 and FIG. 4 , it is possible to time multiplex a data block for retransmission, as shown in FIG. 5 , and it is also possible to code multiplex a data block for retransmission.",
"Embodiment 2 [0071] A case has been described with Embodiment 1 where a time slot for retransmission is provided per predetermined period, and data blocks in response to which a NACK is sent by feedback are multiplexed and combined to be arranged in that time slot for retransmission.",
"[0072] A case will be described with the present embodiment where, when the number of different data blocks in response to which a NACK is sent by feedback reaches predetermined number M, a time slot for retransmission is provided, and M data blocks in response to which a NACK is sent by feedback is multiplexed and combined to be arranged in that time slot for retransmission.",
"[0073] FIG. 6 shows a principal-part configuration of a transmitting base station according to the present embodiment.",
"In the base station of FIG. 6 according to the present embodiment, parts that are the same as in FIG. 1 will be assigned the same reference numerals as in FIG. 1 and overlapping explanations will be omitted.",
"Compared to base station 100 of FIG. 1 , base station 100 A of FIG. 6 includes retransmission control section 109 A, multiplexing section 113 A, arrangement section 114 A, and modulation section 115 A, instead of retransmission control section 109 , multiplexing section 113 , arrangement section 114 , and modulation section 115 .",
"[0074] Retransmission control section 109 A controls retransmission of a data block based on the response signal and the data block number that are input from retransmission request detection section 108 .",
"Specifically, retransmission control section 109 A outputs the data block number in response to which a NACK is reported, which is input from retransmission request detection section 108 , to encoding and modulation section 110 .",
"Further, retransmission control section 109 A counts the number of different data block numbers in response to which a NACK is reported, and when the number of different data block numbers in response to which a NACK is reported reaches predetermined number M, outputs a control signal for reporting that the number of different data block numbers in response to which a NACK is reported has reached predetermined number M, to multiplexing section 113 A, arrangement section 114 A, and modulation section 115 A. Further, in the case where base station 100 A sets the value of predetermined number M arbitrarily, retransmission control section 109 A outputs information about predetermined number M to modulation section 115 A. [0075] Upon receiving the control signal from retransmission control section 109 A, multiplexing section 113 A multiplexes M data blocks for retransmission to generate a multiplexed block.",
"For the multiplexing method, multiplexing section 113 A uses time division multiplexing, frequency division multiplexing, or code division multiplexing.",
"Multiplexing section 113 A outputs the generated multiplexed block to arrangement section 114 A. [0076] Arrangement section 114 A arranges the data blocks for the initial transmission and the multiplexed block in time slots, and outputs the arranged data blocks for the initial transmission and multiplexed block, to data and control signal multiplexing section 116 .",
"Specifically, upon receiving the control signal to report that the number of different block numbers in response to which a NACK is reported has reached predetermined number M from retransmission control section 109 A, arrangement section 114 A provides a time slot for retransmission, and arranges the multiplexed block in that time slot for retransmission.",
"The method of arrangement in arrangement section 114 A will be described later.",
"[0077] Modulation section 115 A modulates the control information including information about the data block number contained in the multiplexed block and information about the position of the time slot for retransmission, and outputs the modulated control information to data and control signal multiplexing section 116 .",
"Further, when receiving as input information about predetermined number M from retransmission control section 109 A, modulation section 115 A performs modulation by including information about predetermined number M in the control information.",
"[0078] FIG. 7 shows a principal-part configuration of a receiving terminal according to the present embodiment.",
"In the terminal of FIG. 7 according to the present embodiment, parts that are the same as in FIG. 2 will be assigned the same reference numerals as in FIG. 2 and overlapping explanations will be omitted.",
"Compared to terminal 200 of FIG. 2 , terminal 200 A of FIG. 7 is configured to include multiplexing information detection section 203 A, time slot demultiplexing section 204 A, and block demultiplexing section 206 A, instead of multiplexing information detection section 203 , time slot demultiplexing section 204 , and block demultiplexing section 206 .",
"[0079] Multiplexing information detection section 203 A detects the position of the time slot for retransmission in which a multiplexed block is arranged, from the control information contained in the reception signal, and outputs information about the detected position of the time slot for retransmission, to time slot demultiplexing section 204 A. Further, in the case where information about predetermined number M is contained in the control information, multiplexing information detection section 203 A outputs the information about predetermined number M to block demultiplexing section 206 A. [0080] Time slot demultiplexing section 204 A demultiplexes the data block for the initial transmission that is arranged in the time slot for the initial transmission and the multiplexed block arranged in the time slot for retransmission, from the reception-processed signal, using information of the position of the time slot for retransmission reported from multiplexing information detection section 203 A. Then, time slot demultiplexing section 204 A outputs the data block for the initial transmission to demodulation section 205 , and outputs the data block for retransmission to block demultiplexing section 206 A. [0081] Block demultiplexing section 206 A demultiplexes the multiplexed block arranged in the time slot for retransmission that is input from time slot demultiplexing section 204 A, into M data blocks for retransmission, based on predetermined multiplexing number M, by associating the multiplexed block with the multiplexing method in multiplexing section 113 A of base station 100 A. Block demultiplexing section 206 A outputs the demultiplexed data block for retransmission to demodulation section 207 .",
"[0082] Next, the method of arranging time slots for retransmission according to the present embodiment will be described with reference to FIG. 8 .",
"[0083] FIG. 8 shows an example of correspondence between data blocks arranged in respective time slots (T 1 to T 8 ) and response signals reported from four terminals (UE # 1 to UE # 4 ) in response to respective data block numbers (# 1 to # 6 ).",
"[0084] According to the present embodiment, arrangement section 114 A provides a time slot for retransmission, when the number of different blocks in response to which a NACK is reported reaches predetermined number M. [0085] In FIG. 8 , time slots TI, T 2 , T 4 to T 6 , and T 8 are time slots for the initial transmission, and time slots T 3 and T 7 are time slots for retransmission, and FIG. 8 shows a case where time slots for retransmission are provided when the number of different blocks in response to which a NACK is reported is two.",
"[0086] Specifically, in the case where NACKs are reported from UEs # 2 , # 3 , and # 4 in response to data block for the initial transmission # 1 that is transmitted in time slot T 1 , and a NACK is reported from UE # 4 in response to data block for the initial transmission # 2 that is transmitted in time slot T 2 , retransmission control section 109 A outputs a control signal for reporting that the number of different data block numbers in response to which a NACK is reported becomes a predetermined number of two, to multiplexing section 113 A. [0087] Multiplexing section 113 A multiplexes data blocks # 1 and # 2 to generate a multiplexed block, and arrangement section 114 A provides a time slot for retransmission in time slot T 3 and arranges the multiplexed block in that time slot T 3 .",
"[0088] As described above, according to the present embodiment, in the case where the number of different data blocks in response to which a NACK is reported reaches predetermined number M, arrangement section 114 A provides a time slot for retransmission, and multiplexes and combines the data blocks in response to which a NACK is sent by feedback to arrange the multiplexed and combined data block in that time slot for retransmission.",
"By this means, it is possible to ensure retransmission to all terminals that have sent a NACK by feedback, that is, in the case of FIG. 8 , UE # 2 to UE # 4 .",
"Further, data blocks for retransmission are arranged to be multiplexed in one time slot, it is possible to reduce the loss of the efficiency of frequency of downlink channel radio resources due to retransmission.",
"Further, it is possible to set a limit to the number of data blocks to be multiplexed, so that, by setting predetermined number M as an appropriate value, it is possible to prevent the condition where radio resources in data blocks for retransmission is divided into a large numbers and radio resources to be assigned to each data block for retransmission becomes extremely scarce, making it possible to ensure appropriate radio resources for a data block for retransmission.",
"[0089] The multiplexing number of a data block for retransmission is not limited to two, and it is possible to provide base station 100 A and terminal 200 A with multiplexing number M in advance, or it is possible to report multiplexing number M from base station 100 A to terminal 200 A. cl Embodiment 3 [0090] A method of assigning radio resources to a data block for retransmission that is to be arranged by being multiplexed in a time slot for retransmission, will be described with the present embodiment.",
"[0091] FIG. 9 shows a principal-part configuration of transmitting base station 300 according to the present embodiment.",
"In base station 300 of FIG. 9 according to the present embodiment, parts that are the same as in FIG. 1 will be assigned the same reference numerals as in FIG. 1 and overlapping explanations will be omitted.",
"Compared to base station 100 of [0092] FIG. 1 , base station 300 of FIG. 9 is configured to include retransmission control section 302 and modulation section 303 , instead of retransmission control section 109 and modulation section 115 , and add channel quality indicator (CQI) extraction section 301 .",
"[0093] CQI extraction section 301 extracts channel quality indicator (CQI) of each terminal from demodulated control information, and outputs information about the extracted CQI to retransmission control section 302 .",
"[0094] Retransmission control section 302 , in the same way as retransmission control section 109 , controls retransmission of a data block based on the response signal and the data block number input from retransmission request detection section 108 .",
"Further, retransmission control section 302 determines the encoding rate and the modulation level for generating a data block for retransmission and radio resources to which that data block for retransmission is assigned, so as to assign the data block for retransmission of the data block in response to which a NACK is reported, to radio resources having better channel quality of a terminal that has returned that NACK, based on the channel quality indicator (CQI) of the terminal that has reported the NACK.",
"Retransmission control section 302 outputs information about the determined encoding rate and modulation level to encoding and modulation section 110 , and outputs information about the radio resources to which a data block for retransmission is to be assigned, to multiplexing section 113 and modulation section 303 .",
"[0095] In addition to the operation of modulation section 115 , modulation section 303 performs modulation by including information about radio resources to which a data block for retransmission is to be assigned in the control information.",
"[0096] FIG. 10 shows a principal-part configuration of a transmitting terminal according to the present embodiment.",
"In terminal 400 of FIG. 10 according to the present embodiment, parts that are the same as in FIG. 2 will be assigned the same reference numerals as in FIG. 2 and overlapping explanations will be omitted.",
"Compared to terminal 200 of FIG. 2 , terminal 400 of FIG. 10 is configured to include modulation section 402 instead of modulation section 210 , and add channel condition detection section 401 .",
"[0097] Channel condition detection section 401 detects the condition of a channel using the control signal transmitted from base station 300 , and outputs the detected channel condition to modulation section 402 as a channel quality indicator (CQI).",
"[0098] Modulation section 402 modulates the control signal input from error detection section 209 and the channel quality indicator (CQI) input from channel condition detection section 401 , and outputs the modulated control signal to radio transmission section 211 .",
"[0099] Next, a method of assigning radio resources to a data block for retransmission according to the present embodiment, will be described with reference to FIG. 11 .",
"[0100] FIG. 11 shows an example of correspondence between data blocks arranged in respective time slots (T 1 to T 8 ) and response signals reported from four terminals (UE # 1 to UE # 4 ) in response to respective data block numbers (# 1 to # 6 ).",
"[0101] In FIG. 11 , time slots T 1 to T 3 and T 5 to T 7 are time slots for the initial transmission, and time slots T 4 and T 8 are time slots for retransmission, and FIG. 10 , in the same way as FIG. 3 , shows a case where time slots for retransmission are provided per predetermined period, per four time slots.",
"[0102] In this case, in the same way as in FIG. 3 , consider a case where NACKs are reported from UEs # 2 , # 3 , and # 4 in response to data block # 1 that is transmitted in time slot for the initial transmission T 1 , and a NACK is reported from UE # 4 in response to data block # 2 that is transmitted in time slot for the initial transmission T 2 , and ACKs are reported from all UEs # 1 to # 4 in response to data block # 3 that is transmitted in time slot for the initial transmission T 3 .",
"[0103] Retransmission control section 302 determines the encoding rate and the modulation level for generating a data block for retransmission and radio resources for assigning that data block for retransmission, so as to assign the data block for retransmission of the data block in response to which a NACK is reported, to radio resources having good channel quality of a terminal that has returned that NACK, based on the channel quality indicator (CQI) of the terminal that reports the NACK in the time slot interposed between the time slots for retransmission.",
"[0104] For example, in the case where, in time slots T 1 to T 3 , the channel quality of UEs # 2 and # 3 that have reported a NACK in response to data block # 1 is better as the frequency decreases, and the channel quality of UE # 4 that has reported a NACK in response to data block # 2 is better as the frequency increases, retransmission control section 302 assigns data block # 1 to the low-frequency area, and assigns data block # 2 to the high-frequency area, in the radio resources of the time slot for retransmission (see FIG. 11 ), and outputs information about radio resources to which the data block for retransmission will be assigned, to multiplexing section 113 .",
"[0105] Further, in the case where, in time slots T 5 to T 7 , the channel quality of UE # 3 that has reported a NACK in response to data block # 5 is better nearer the center of the frequency, and the channel quality of UE # 4 that has reported a NACK in response to data block # 6 is better as the frequency decreases, retransmission control section 302 assigns data block # 5 to the center area of frequency, assigns data block # 6 to the low-frequency area, and assigns the remaining data block # 4 to the high-frequency area, in the radio resources of the time slots for retransmission (see FIG. 11 ), and outputs information about radio resources to which the data block for retransmission will be assigned, to multiplexing section 113 .",
"[0106] The example shown in FIG. 11 is a case where the proportion of radio resources to assign is made larger, for transmission data of a data block having a larger number of NACKs reported, that is, transmission data of a data block having a larger number of NACKs reported from different terminals, out of data blocks for retransmission to be multiplexed.",
"[0107] As described above, according to the present embodiment, retransmission control section 302 determines radio resources to which data blocks for retransmission are assigned, based on the channel quality of a terminal that has reported a retransmission request.",
"By this means, multiplexing section 113 can assign a data block for retransmission to radio resources having good channel quality of a terminal that has reported a retransmission request, so that it is possible to prevent a retransmission request from being reported again and improve the efficiency of retransmission.",
"[0108] Although a method of assigning radio resources to a data block for retransmission to be multiplexed and arranged in the time slot for retransmission that is described in Embodiment 1, has been described with the above embodiment, it is also possible to apply the radio resource assignment method described in the present embodiment to a data block for retransmission to be multiplexed and arranged in the time slot for retransmission that is described in Embodiment 2.",
"[0109] Further, the above descriptions are examples of preferable embodiments of the present invention and the scope of the present invention is not limited to these.",
"[0110] Further, in the above descriptions, a data block refers to a unit for encoding and decoding, and it is possible to substitute “transport block,” “code ward,” or “packet,” for example, for “data block.”",
"Further, in the above descriptions, “a time slot”",
"refers to a transmission time unit, and it is possible to substitute “subframe”",
"or “frame,” for example for “time slot.”",
"[0111] The disclosure of Japanese Patent Application No. 2009-130869, filed on May 29, 2009, including the specification, drawings and abstract, is incorporated herein by reference in its entirety.",
"INDUSTRIAL APPLICABILITY [0112] The present invention is useful, for example, for a base station apparatus, a terminal apparatus, a radio communication system, and a transmission method in an MBMS system.",
"REFERENCE SIGNS LIST [0000] 100 , 100 A, 300 Base station 101 Division section 102 , 110 Encoding and modulation section 103 , 111 Encoding section 104 , 112 , 115 , 115 A, 210 , 303 , 402 Modulation section 106 , 202 Radio reception section 105 , 201 Antenna 107 , 205 , 207 Demodulation section 108 Retransmission request detection section 109 , 109 A, 302 Retransmission control section 113 , 113 A Multiplexing section 114 , 114 A Arrangement section 116 Data and control signal multiplexing section 117 , 211 Radio transmission section 200 , 200 A, 400 Terminal 203 , 203 A Multiplexing information detection section 204 , 204 A Time slot demultiplexing section 206 , 206 A Block demultiplexing section 208 Decoding section 209 Error detection section"
] |
FIELD OF THE INVENTION
The present invention relates to a glass plate having electrically charge-preventive film of conductive organic polymer, its making method, a solution for making the film, and its manufacturing method. In detail, it relates to an anti-static film formed using electroconductive organic polymer on the surface of the glass plate, particularly, an image display faceplate or a screen portion in a panel of a CRT 1 so as to improve the electrically charge-preventive so anti-static characteristics of the glass plate, such as the image display faceplate.
Recently, a wide use of an anti-explosion type cathode ray tube allows a face cover glass to be unnecessary in a television receiver, a monitor, etc., regarding the prevention of electrostatic charge, thereby exposing the front portion of the cathode ray tube, and giving electric shock by charged electrical high voltage, to the person who comes access, to the faceplate of the cathode ray tube. Furthermore, dust in air, particles, etc., are adhered to by the electric force, and accumulated on, the charged faceplate of the cathode ray tube, thereby having the image on the display faceplate difficult to see.
The cause of electrostatic charge as to the faceplate panel as one example of the glass plate is as follows.
A thin and uniform aluminium film is deposited by vacuum on the phosphor screen structure on the interior surface of the faceplate panel. When a electric power is applied to, a high anode voltage is applied to the aluminium film. Electric charges generate on the exterior surface wall of the panel by electrostatic induction due to the high voltage of the inside aluminium film.
Korean patent publication No. 2713 as one prior arts for providing an anti-static characteristics on the image display faceplate describes one such anti-static coating formed by the steps of preparing a slurry by mixing an alcohol solution containing alkoxysilane Si(OR) 4 (R is an alkyl group) and at least one of tin oxide, indium oxide and antimony oxide, spraying the slurry on the faceplate panel, and heat-treating the sprayed panel at a relatively low temperature.
U.S. Pat. No. 5,750,054, issued to Patrizia Cinquina, Vasto, et al. on May 12, 1998, discloses an anti-static, anti-glare coating for a reflective-transmissive surface wherein the surface is applied onto with a coating solution comprising a thiophene-based, electroconductive polymer and a siliceous material. As the concrete electroconductive polymer, polyethylenedioxythiophene, and as a siliceous material, lithium-stabilized silica sol and tetraethoxysilane are disclosed.
Further, U.S. Pat. No. 5,742,119 issued to Aben, et al. on Apr. 21, 1998, discloses a display screen of a cathode ray tube provided with an electroconductive coating of poly-3,4-ethylenedioxythiophene. The coating layer has a sheet resistance of 1 kilo-ohm/quadrature and a high transmission. The layer provides an effective shield against electromagnetic radiation. The coating can be provided with additional layers of, for example, silicon dioxide to improve the mechanical properties.
However, the metallic oxide costs too much, thereby making the manufacturing cost very high.
Further, the problem is that while the metallic oxide exists dispersedly in the alcohol solution, deposition problem arises due to cohesion between the particles according the condition of the surroundings, thereby making spots or unevenness and lowering the electroconductivity.
Accordingly, it is one object of the present invention to provide a glass plate such as image display faceplate having high-electroconductive film which can be formed using electroconductive organic polymer in a simple method and at a low cost, and have an improved anti-static characteristic with a strong film hardness and a strong adhesive strength. Also, the present invention provides a method of making such film , said method comprising the steps of obtaining a anti-static layer by dissolving in alcohol an aqueous solution of electroconductive organic polymers and applying the resultant dissolved solution, and then spin overcoating an alcoholic solution of silicon alkoxide and heat-treating the resultant overcoated film. If necessary, an additional anti-glare layer may be further formed by spraying the alcoholic solution of silicon alkoxide onto the anti-static layer or the resultant film of the alcoholic solution of silicon alkoxide.
SUMMARY OF THE INVENTION
To accomplish the aforementioned purpose, the present invention provides a glass plate on which an anti-static film is formed on the exterior surface, said film comprising a first coating layer formed containing an electroconductive organic polymeric component and a second coating layer of silica coating formed by being overcoated onto the first coating layer.
Said first coating layer may be formed by coating an electroconductive organic polymeric solution containing 0.005-0.5 wt. % of polyethylenedioxythiophene which polystyrenesulphonate is doped to and silicon alkoxide of below 10 wt. %, and said electroconductive organic polymeric solution may contain 40-90 wt. % of at least one alcoholic solvent selected from a group consisting of a methanol, an ethanol, an isopropanol, a butanol, and combinations thereof, 5-70 wt. % of pure water, and 1-20 wt. % of at least one co-solvent selected from a group consisting of a compound having a carbonyl group, an ether, and combinations thereof. And, said second coating layer is formed by overcoating with alkoxysilane Si(OR) 4 .
The anti-static film may have an anti-glare characteristic itself, and otherwise at least one anti-glare film formed thereon. Such glass plate may be an image display faceplate or a screen portion in a panel of a CRT.
Also, the present invention provides a method of forming a anti-static film on a surface of a glass plate, the method comprising the steps of: first-coating an electroconductive organic polymeric solution on the surface of the glass plate, said solution containing 0.005-0.5 wt. % of polyethylenedioxythiophene which polystyrenesulphonate is doped to and silicon alkoxide of below 10 wt. %; and second-coating alkoxysilane Si(OR) 4 after the first-coating step.
Furthermore, the present invention provides a solution for applying onto a surface of a glass plate in order to form an anti-static film, said solution containing 0.005-0.5 wt. % of polyethylenedioxythiophene which polystyrenesulphonate is doped to, silicon alkoxide of below 10 wt. %, 40-90 wt. % of at least one alcoholic solvent selected from a group consisting of a methanol, an ethanol, an isopropanol, a butanol, and combinations thereof, 5-70 wt. % of pure water, and 1-20 wt. % of at least one co-solvent selected from a group consisting of a compound having a carbonyl group, an ether, and combinations thereof.
It is preferred, in the electroconductivity, that said solution contain said silicon alkoxide of below 2 wt. %.
Furthermore, the present invention provides a method of making a solution for applying onto a surface of a glass plate in order to form an anti-static film, said solution being prepared by the steps of: dissolving in alcohol an aqueous solution of electroconductive organic polymers; first-adding silicon alkoxide to the alcoholic solution for improving the cohesive strength; and second-adding pure water and an inorganic acid catalyst for hydrolysis, and co-solvent for improving the application property.
The anti-static film formed by such method, comprises a first coating layer having fine porosities and an excellent electroconductive property, and a second coating layer formed by being overcoated with a material of a strong adhesive strength onto the first coating layer so as to adhere to at least the glass plate by penetrating through the porosities of the first coating layer, thus the anti-static film is adhered to the glass plate due to the strong adhesive strength without being scaled off and with obtaining an excellent electroconductive characteristic of the first coating layer.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the principle and nature of the present invention reference should be made to the following detailed description taken in connection with the accompanying drawings in which:
FIG. 1 is a schematical side view partially in axial section of a color cathode-ray tube, wherein an electroconductive organic polymeric anti-static film is formed on the exterior surface of a faceplate panel thereof according to one embodiment of the present invention;
FIG. 2 is an enlarged sectional view of one portion in a panel in FIG. 1;
FIG. 3 is an enlarged sectional view similar to FIG. 2, showing an electroconductive organic polymeric anti-static film formed on a general glass plate according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 and FIG. 2 show a color cathode ray tube as one example of an image display faceplate among a glass plate for an explanation of one embodiment of the present invention.
In FIG. 1, an electroconductive organic polymeric anti-static film 10 is formed on the exterior surface of a faceplate panel 2 in a color cathode ray tube 1 . A grounded anti-explosion band 4 comes into contact with the anti-static film 10 and makes the potential of the overall surface of the anti-static film 10 zero, thereby preventing electrical charge.
In FIGS. 1 and 2, the anti-static film 10 according to the present invention comprises a first coating layer 11 formed containing an electroconductive organic polymeric component and a second coating layer 12 of silica coating formed by being overcoated onto the first coating layer 11 , being characterizing in that the first coating layer 11 has fine porosities 11 ′ and an excellent electroconductive property, and that the second coating layer 12 adheres to at least the glass plate 2 ′ with a strong adhesive strength by penetrating through the porosities 11 ′, 21 ′ of the first coating layer 11 , 21 . Embodiments according to the present invention, using an electroconductive organic polymeric solution containing 0.005-0.5 wt. % of polyethylenedioxythiophene which polystyrenesulphonate is doped to as the organic polymer of the first coating layer 11 , and using alkoxysilane Si(OR) 4 (R is an alkyl group as a solution for making said second coating layer 12 , are explained as follows.
EXAMPLE 1
In FIGS. 1 and 2, the anti-static film 10 is formed according to the present invention as follows.
That is, an aqueous solution of polyethylenedioxythiophene(PEDT/PSS) which polystyrene sulphonate is doped to is dissolved in methanol. Sequently, ethylsilicate(Si(OC 2 H 5 ) 4 ) as an adhesive agent is added to the aqueous solution(PEDT/PSS aqueous solution), thereby the electroconductive solution being prepared. Then, pure water and an inorganic acid catalyst for hydrolysis, for example hydrochloric acid (HCl) are added, and dispersion agent is finally added, thus an electroconductive organic polymeric solutions prepared. Then, in an upward state of the exterior surface of the faceplate panel 2 of the color cathode ray tube 1 , the color cathode ray tube 1 is rotated with around 130 rpm and the prepared solution is dropped on the exterior surface of the faceplate panel 2 , thus a first coating layer 11 of a thin and uniform thickness is formed. This spin-coating is completed for about 1 minute 10 seconds. Following this spin-coating, a second coating layer 12 is formed by spin-coating alkoxysilane(Si(OR) 4 ) on the first coating layer 11 , thereby making the anti-static film 10 as shown in FIG. 2 with an excellent adhesion between the first coating layer 11 and the panel 2 . This spin-coating is completed for about 1 minute 20 seconds. At the last time, the anti-static film 10 is baked at above about 150 degrees centigrade for 30 minutes, thereby the anti-static film 10 comprising the first coating layer 11 and the second coating layer 12 being completely formed.
The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.30 wt. %
ETHYL SILICATE
0.50 wt. %
ETHANOL
60.19 wt. %
ISOPROPANOL
10.00 wt. %
PURE WATER
25.00 wt. %
HYDROCHLORIC ACID (HCl, 35%)
0.01 wt. %
N-METHYL-2-PYRROLIDONE
2.00 wt. %
ETHYL CELLOSOLVE
2.00 wt. %
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1. Surface resistivity: 9*10 3 ohms/sq. (Ω/□)
2. Film hardness: 7H
EXAMPLE 2
The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, the content of ethylsilicate is increased for improving the film hardness; and diacetonealcohol is added for improving the application characteristics. The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.30 wt. %
ETHYL SILICATE
1.00 wt. %
ETHANOL
57.69 wt. %
ISOPROPANOL
10.00 wt. %
PURE WATER
25.00 wt. %
HYDROCHLORIC ACID (HCl, 35%)
0.01 wt. %
N-METHYL-2-PYRROLIDONE
2.00 wt. %
ETHYL CELLOSOLVE
2.00 wt. %
DIACETONEALCOHOL
2.00 wt. %
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1. Surface resistivity: 44*10 4 ohms/sq.
2. Film hardness: 8H
EXAMPLE 3
The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, the content of PEDT/PSS is increased for improving the electroconductivity, and methylethylketone (MEK is added as a co-solvent for lowering the surface tension of the solution and improving the application characteristics. The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.50 wt. %
ETHYL SILICATE
0.50 wt. %
ETHANOL
57.99 wt. %
ISOPROPANOL
10.00 wt. %
PURE WATER
25.00 wt. %
HYDROCHLORIC ACID (HCl, 35%)
0.01 wt. %
ETHYL CELLOSOLVE
3.00 wt. %
MEK (METHYLETHYLKETONE)
3.00 wt. %
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1) Surface resistivity: 8*10 3 ohms/sq.
2) Film hardness: 7H
EXAMPLE 4
The coating method is the same as that in EXAMPLE 1, but instead of ethyl silicate as a solvent in the electroconductive organic polymeric solution, butanol is used. The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.30 wt. %
ETHANOL
60.70 wt. %
BUTANOL
10.00 wt. %
PURE WATER
25.00 wt. %
PROPYLENE GLYCOL MONO METHYL ESTER
2.00 wt. %
ETHYL CELLOSOLVE
2.00 wt. %
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1) Surface resistivity: 4*10 3 ohms/sq.
2) Film hardness: 6H
EXAMPLE 5
The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a solvent and a co-solvent are changed for improving the electroconductivity. The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.30 wt. %
ETHYL SILICATE
0.50 wt. %
ETHANOL
58.19 wt. %
METHANOL
10.00 wt. %
PURE WATER
25.00 wt. %
HYDROCHLORIC ACID (HCl, 35%)
0.01 wt. %
N-METHYL-2-PYRROLIDONE
2.00 wt. %
BUTYL CELLOSOLVE
2.00 wt. %
ETHYL CELLOSOLVE
2.00 wt. %
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1) Surface resistivity: 8*10 3 ohms/sq.
2) Film hardness: 7H
EXAMPLE 6
The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a content of pure water, and a solvent and a co-solvent are changed for improving the application characteristic. The constituents and the contents of the electroconductive organic polymeric solution or forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.30 wt. %
ETHYL SILICATE
0.50 wt. %
ETHANOL
58.19 wt. %
METHANOL
3.00 wt. %
ISOPROPYL ALCOHOL
17.00 wt. %
PURE WATER
15.00 wt. %
HYDROCHLORIC ACID (HCl, 35%)
0.01 wt. %
N-METHYL-2-PYRROLIDONE
2.00 wt. %
BUTYL CELLOSOLVE
2.00 wt. %
ETHYL CELLOSOLVE
2.00 wt. %
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1) Surface resistivity: 1*10 4 ohms/sq.
2) Film hardness: 7H
EXAMPLE 7
The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, contents of pure water and ethylsilicate, and a solvent and a co-solvent are changed. The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.30 wt. %
ETHYL SILICATE
0.40 wt. %
ETHANOL
58.29 wt. %
METHANOL
10.00 wt. %
ISOPROPYL ALCOHOL
10.00 wt. %
PURE WATER
15.00 wt. %
HYDROCHLORIC ACID (HCl, 35%)
0.01 wt. %
N-METHYL-2-PYRROLIDONE
2.00 wt. %
PROPYLENE GLYCOL MONO METHYL ESTER
2.00 wt. %
ETHYL CELLOSOLVE
2.00 wt. %
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1) Surface resistivity: 6*10 3 ohms/sq.
2) Film hardness: 7H
EXAMPLE 8
The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a content of PEDT/PSS is decreased. The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.10
ETHYL SILICATE
0.50
ETHANOL
70.39
ISOPROPANOL
10.00
PURE WATER
15.00
HYDROCHLORIC ACID (HCl, 35%)
0.01
N-METHYL-2-PYRROLIDONE
2.00
ETHYL CELLOSOLVE
2.00
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1) Surface resistivity: 1*10 5 ohms/sq.
2) Film hardness: 8H
EXAMPLE 9
The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a content of PEDT/PSS is remarkably decreased. The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.005
ETHYL SILICATE
0.50
ETHANOL
80.485
ISOPROPANOL
10.00
PURE WATER
5.00
HYDROCHLORIC ACID (HCl, 35%)
0.01
N-METHYL-2-PYRROLIDONE
2.00
ETHYL CELLOSOLVE
2.00
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1) Surface resistivity: 3*10 6 ohms/sq.
2) Film hardness: 8H
EXAMPLE 10
The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a content of PEDT/PSS is extremely decreased. The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.001
ETHYL SILICATE
0.50
ETHANOL
80.489
ISOPROPANOL
10.00
PURE WATER
5.00
HYDROCHLORIC ACID (HCl, 35%)
0.01
N-METHYL-2-PYRROLIDONE
2.00
ETHYL CELLOSOLVE
2.00
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1) Surface resistivity: 4*10 3 ohms/sq.
2) Film hardness: 8H
EXAMPLE 11
The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a content of PEDT/PSS is remarkably increased. The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows:
CONSTITUENTS OF THE ELECTRO-
CONTENT
CONDUCTIVE ORGANIC POLYMERIC SOLUTION
(wt. %)
PEDT/PSS
0.65
ETHYL SILICATE
0.50
ETHANOL
31.84
ISOPROPANOL
10.00
PURE WATER
53.00
HYDROCHLORIC ACID (HCl, 35%)
0.01
N-METHYL-2-PYRROLIDONE
2.00
ETHYL CELLOSOLVE
2.00
In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows:
1) Surface resistivity: 6*10 3 ohms/sq.
2) Film hardness: 5H
As found from the above-described Examples 1 to 11, within the scope of the appended claims according to the present invention, it is realized to form, on the image display faceplate, the anti-static film 10 comprising a first coating layer 11 of high-electroconductivity containing an electroconductive organic polymeric component. And, when the minimum of the ethyl silicate, i.e., only a binder is contained in the electroconductive first coating layer 11 , the electroconductivity can be maximized.
That is, compared with the examples 1 to 7 and 11, the examples 8, 9 and 10 shows the very high surface resistivity, thereby conspicuously lowering the electroconductivity. Particularly, in less than 0.005 wt. % of PEDT/PSS as shown in the example 10, the electroconductivity becomes abruptly lowered, while, PEDT/PSS of above 0.005 wt. % is contained as shown in the example 11, the spin coating is difficult(the application characteristics become lowered and the film hardness becomes remarkably lowered due to the increase of the viscosity. Therefore, the content of PEDT/PSS between 0.1 to 0.3 wt. % is found to be proper as an electroconductive organic polymeric anti-static film for the image display faceplate.
Furthermore, the alkoxysilane solution is overcoating on the first coating layer 11 and permeated in the firs coating layer 11 , thereby making the silica film on the panel 2 and increasing the sticking strength. Therefore, the first coating layer 11 becomes strongly attached to the panel 2 and the film hardness increased.
Thus, the anti-static film 10 having an excellent shield effect′ against electromagnetic radiation and the superior anti-static characteristics can be obtained. Further, compared with the conventional metallic oxide coating, the manufacturing cost of the anti-static film 10 according to the present invention becomes lowered and its method simpler. Also, deposition problem was not found, thereby making the coating on the exterior surface of the faceplate even without any spots. The reason is understood to be that the solution used in the present invention does not comprise any inorganic slurry.
FIG. 3 is an enlarged sectional view similar, in part, showing an electroconductive organic polymeric anti-static film 20 formed on a general glass plate 2 ′ according to another embodiment of the present invention by means of the forementioned method.
In FIG. 3, the anti-static film 20 comprises a first coating layer 21 formed containing an electroconductive organic polymeric component and a second coating layer 22 of silica coating formed by being overcoated onto the first coating layer 21 , said anti-static film 20 having fine porosities 21 ′, as shown in FIG. 2 . That is, the anti-static film 20 comprises the first coating layer 21 having fine porosities 21 ′ with an excellent electroconductivity, and the second coating layer 22 penetrates through the porosities 21 ′ of the first coating layer 21 when overcoated on the first coating layer 21 , thereby being adhered to at least the surface of the glass plate 2 ′. Therefore, the second coating layer 22 is very high in the film hardness and the adhesive strength.
In examples for the glass plate 2 ′, using an electroconductive organic polymeric solution containing 0.005-0.5 wt. % of polyethylenedioxythiophene which polystyrenesulphonate is doped to as the organic polymer of the first coating layer 21 , and using alkoxysilane Si(OR4(R is an alkyl group as a solution for making said second coating layer 12 , and similar to the above-described examples for the panel 2 , the coating structure of the electroconductive organic polymeric film is formed as shown in FIG. 3, and each surface resistivity and each film hardness in the pencil test are similar to those in each examples above for the panel 2 .
Therefore, except for an image display faceplate, the anti-static film 20 can be used for the general glass plate in which the anti-static characteristic is required like a monitor protective cover and also, for the shield effect against electromagnetic radiation or the anti-reflective effect.
Meanwhile, an anti-reflective layer 23 can be formed even in this embodiment for a more effective anti-reflection as shown in phantom line in FIG. 3 .
As understood from the above-described embodiments, the present invention enables an anti-static coating on a general glass plate having high electroconductivity or superior anti-static characteristics, very high sticking strength and film hardness, etc., and at the lower manufacturing cost and in the simple manufacturing method. It should be clear to one skilled in the art that the present invention can be altered and applied without any limitation to the aforementioned embodiments of the present invention and within the scope of the present invention's spirit. | A glass plate having high-electroconductive film which can be formed using electroconductive organic polyrmer in a simple method and at a low cost, and having an improved anti-static characteristic with a strong film hardness and a strong adhesive strength. The glass plate has an anti-static film ( 10, 20 ) formed on the exterior surface, the film comprising a first coating layer ( 11, 21 ) formed containing an electroconductive organic polymeric component and a second coating layer ( 12, 22 ) of silica coating formed by being overcoated onto the first coating layer ( 11, 21 ). The electroconductive organic polymeric solution contains 0.005-0.5 wt. % of polyethylenedioxythiophene which polystyrenesulphonate is doped to and silicon alkoxide of below 10 wt. %, and also may contain 40-90 wt. % of at least one a selected from a group consisting of a methanol, an ethanol, an isopropanol, a butanol, and combinations thereof, 5-70 wt. % of pure water, and 1-20 wt. % of at least one co-solvent selected from a group consisting of a compound having a carbonyl group, an ether, and combinations thereof. | Summarize the patent information, clearly outlining the technical challenges and proposed solutions. | [
"FIELD OF THE INVENTION The present invention relates to a glass plate having electrically charge-preventive film of conductive organic polymer, its making method, a solution for making the film, and its manufacturing method.",
"In detail, it relates to an anti-static film formed using electroconductive organic polymer on the surface of the glass plate, particularly, an image display faceplate or a screen portion in a panel of a CRT 1 so as to improve the electrically charge-preventive so anti-static characteristics of the glass plate, such as the image display faceplate.",
"Recently, a wide use of an anti-explosion type cathode ray tube allows a face cover glass to be unnecessary in a television receiver, a monitor, etc.",
", regarding the prevention of electrostatic charge, thereby exposing the front portion of the cathode ray tube, and giving electric shock by charged electrical high voltage, to the person who comes access, to the faceplate of the cathode ray tube.",
"Furthermore, dust in air, particles, etc.",
", are adhered to by the electric force, and accumulated on, the charged faceplate of the cathode ray tube, thereby having the image on the display faceplate difficult to see.",
"The cause of electrostatic charge as to the faceplate panel as one example of the glass plate is as follows.",
"A thin and uniform aluminium film is deposited by vacuum on the phosphor screen structure on the interior surface of the faceplate panel.",
"When a electric power is applied to, a high anode voltage is applied to the aluminium film.",
"Electric charges generate on the exterior surface wall of the panel by electrostatic induction due to the high voltage of the inside aluminium film.",
"Korean patent publication No. 2713 as one prior arts for providing an anti-static characteristics on the image display faceplate describes one such anti-static coating formed by the steps of preparing a slurry by mixing an alcohol solution containing alkoxysilane Si(OR) 4 (R is an alkyl group) and at least one of tin oxide, indium oxide and antimony oxide, spraying the slurry on the faceplate panel, and heat-treating the sprayed panel at a relatively low temperature.",
"U.S. Pat. No. 5,750,054, issued to Patrizia Cinquina, Vasto, et al.",
"on May 12, 1998, discloses an anti-static, anti-glare coating for a reflective-transmissive surface wherein the surface is applied onto with a coating solution comprising a thiophene-based, electroconductive polymer and a siliceous material.",
"As the concrete electroconductive polymer, polyethylenedioxythiophene, and as a siliceous material, lithium-stabilized silica sol and tetraethoxysilane are disclosed.",
"Further, U.S. Pat. No. 5,742,119 issued to Aben, et al.",
"on Apr. 21, 1998, discloses a display screen of a cathode ray tube provided with an electroconductive coating of poly-3,4-ethylenedioxythiophene.",
"The coating layer has a sheet resistance of 1 kilo-ohm/quadrature and a high transmission.",
"The layer provides an effective shield against electromagnetic radiation.",
"The coating can be provided with additional layers of, for example, silicon dioxide to improve the mechanical properties.",
"However, the metallic oxide costs too much, thereby making the manufacturing cost very high.",
"Further, the problem is that while the metallic oxide exists dispersedly in the alcohol solution, deposition problem arises due to cohesion between the particles according the condition of the surroundings, thereby making spots or unevenness and lowering the electroconductivity.",
"Accordingly, it is one object of the present invention to provide a glass plate such as image display faceplate having high-electroconductive film which can be formed using electroconductive organic polymer in a simple method and at a low cost, and have an improved anti-static characteristic with a strong film hardness and a strong adhesive strength.",
"Also, the present invention provides a method of making such film , said method comprising the steps of obtaining a anti-static layer by dissolving in alcohol an aqueous solution of electroconductive organic polymers and applying the resultant dissolved solution, and then spin overcoating an alcoholic solution of silicon alkoxide and heat-treating the resultant overcoated film.",
"If necessary, an additional anti-glare layer may be further formed by spraying the alcoholic solution of silicon alkoxide onto the anti-static layer or the resultant film of the alcoholic solution of silicon alkoxide.",
"SUMMARY OF THE INVENTION To accomplish the aforementioned purpose, the present invention provides a glass plate on which an anti-static film is formed on the exterior surface, said film comprising a first coating layer formed containing an electroconductive organic polymeric component and a second coating layer of silica coating formed by being overcoated onto the first coating layer.",
"Said first coating layer may be formed by coating an electroconductive organic polymeric solution containing 0.005-0.5 wt.",
"% of polyethylenedioxythiophene which polystyrenesulphonate is doped to and silicon alkoxide of below 10 wt.",
"%, and said electroconductive organic polymeric solution may contain 40-90 wt.",
"% of at least one alcoholic solvent selected from a group consisting of a methanol, an ethanol, an isopropanol, a butanol, and combinations thereof, 5-70 wt.",
"% of pure water, and 1-20 wt.",
"% of at least one co-solvent selected from a group consisting of a compound having a carbonyl group, an ether, and combinations thereof.",
"And, said second coating layer is formed by overcoating with alkoxysilane Si(OR) 4 .",
"The anti-static film may have an anti-glare characteristic itself, and otherwise at least one anti-glare film formed thereon.",
"Such glass plate may be an image display faceplate or a screen portion in a panel of a CRT.",
"Also, the present invention provides a method of forming a anti-static film on a surface of a glass plate, the method comprising the steps of: first-coating an electroconductive organic polymeric solution on the surface of the glass plate, said solution containing 0.005-0.5 wt.",
"% of polyethylenedioxythiophene which polystyrenesulphonate is doped to and silicon alkoxide of below 10 wt.",
"and second-coating alkoxysilane Si(OR) 4 after the first-coating step.",
"Furthermore, the present invention provides a solution for applying onto a surface of a glass plate in order to form an anti-static film, said solution containing 0.005-0.5 wt.",
"% of polyethylenedioxythiophene which polystyrenesulphonate is doped to, silicon alkoxide of below 10 wt.",
"%, 40-90 wt.",
"% of at least one alcoholic solvent selected from a group consisting of a methanol, an ethanol, an isopropanol, a butanol, and combinations thereof, 5-70 wt.",
"% of pure water, and 1-20 wt.",
"% of at least one co-solvent selected from a group consisting of a compound having a carbonyl group, an ether, and combinations thereof.",
"It is preferred, in the electroconductivity, that said solution contain said silicon alkoxide of below 2 wt.",
"Furthermore, the present invention provides a method of making a solution for applying onto a surface of a glass plate in order to form an anti-static film, said solution being prepared by the steps of: dissolving in alcohol an aqueous solution of electroconductive organic polymers;",
"first-adding silicon alkoxide to the alcoholic solution for improving the cohesive strength;",
"and second-adding pure water and an inorganic acid catalyst for hydrolysis, and co-solvent for improving the application property.",
"The anti-static film formed by such method, comprises a first coating layer having fine porosities and an excellent electroconductive property, and a second coating layer formed by being overcoated with a material of a strong adhesive strength onto the first coating layer so as to adhere to at least the glass plate by penetrating through the porosities of the first coating layer, thus the anti-static film is adhered to the glass plate due to the strong adhesive strength without being scaled off and with obtaining an excellent electroconductive characteristic of the first coating layer.",
"BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the principle and nature of the present invention reference should be made to the following detailed description taken in connection with the accompanying drawings in which: FIG. 1 is a schematical side view partially in axial section of a color cathode-ray tube, wherein an electroconductive organic polymeric anti-static film is formed on the exterior surface of a faceplate panel thereof according to one embodiment of the present invention;",
"FIG. 2 is an enlarged sectional view of one portion in a panel in FIG. 1;",
"FIG. 3 is an enlarged sectional view similar to FIG. 2, showing an electroconductive organic polymeric anti-static film formed on a general glass plate according to another embodiment of the present invention.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 and FIG. 2 show a color cathode ray tube as one example of an image display faceplate among a glass plate for an explanation of one embodiment of the present invention.",
"In FIG. 1, an electroconductive organic polymeric anti-static film 10 is formed on the exterior surface of a faceplate panel 2 in a color cathode ray tube 1 .",
"A grounded anti-explosion band 4 comes into contact with the anti-static film 10 and makes the potential of the overall surface of the anti-static film 10 zero, thereby preventing electrical charge.",
"In FIGS. 1 and 2, the anti-static film 10 according to the present invention comprises a first coating layer 11 formed containing an electroconductive organic polymeric component and a second coating layer 12 of silica coating formed by being overcoated onto the first coating layer 11 , being characterizing in that the first coating layer 11 has fine porosities 11 ′ and an excellent electroconductive property, and that the second coating layer 12 adheres to at least the glass plate 2 ′ with a strong adhesive strength by penetrating through the porosities 11 ′, 21 ′ of the first coating layer 11 , 21 .",
"Embodiments according to the present invention, using an electroconductive organic polymeric solution containing 0.005-0.5 wt.",
"% of polyethylenedioxythiophene which polystyrenesulphonate is doped to as the organic polymer of the first coating layer 11 , and using alkoxysilane Si(OR) 4 (R is an alkyl group as a solution for making said second coating layer 12 , are explained as follows.",
"EXAMPLE 1 In FIGS. 1 and 2, the anti-static film 10 is formed according to the present invention as follows.",
"That is, an aqueous solution of polyethylenedioxythiophene(PEDT/PSS) which polystyrene sulphonate is doped to is dissolved in methanol.",
"Sequently, ethylsilicate(Si(OC 2 H 5 ) 4 ) as an adhesive agent is added to the aqueous solution(PEDT/PSS aqueous solution), thereby the electroconductive solution being prepared.",
"Then, pure water and an inorganic acid catalyst for hydrolysis, for example hydrochloric acid (HCl) are added, and dispersion agent is finally added, thus an electroconductive organic polymeric solutions prepared.",
"Then, in an upward state of the exterior surface of the faceplate panel 2 of the color cathode ray tube 1 , the color cathode ray tube 1 is rotated with around 130 rpm and the prepared solution is dropped on the exterior surface of the faceplate panel 2 , thus a first coating layer 11 of a thin and uniform thickness is formed.",
"This spin-coating is completed for about 1 minute 10 seconds.",
"Following this spin-coating, a second coating layer 12 is formed by spin-coating alkoxysilane(Si(OR) 4 ) on the first coating layer 11 , thereby making the anti-static film 10 as shown in FIG. 2 with an excellent adhesion between the first coating layer 11 and the panel 2 .",
"This spin-coating is completed for about 1 minute 20 seconds.",
"At the last time, the anti-static film 10 is baked at above about 150 degrees centigrade for 30 minutes, thereby the anti-static film 10 comprising the first coating layer 11 and the second coating layer 12 being completely formed.",
"The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.30 wt.",
"% ETHYL SILICATE 0.50 wt.",
"% ETHANOL 60.19 wt.",
"% ISOPROPANOL 10.00 wt.",
"% PURE WATER 25.00 wt.",
"% HYDROCHLORIC ACID (HCl, 35%) 0.01 wt.",
"% N-METHYL-2-PYRROLIDONE 2.00 wt.",
"% ETHYL CELLOSOLVE 2.00 wt.",
"% In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1.",
"Surface resistivity: 9*10 3 ohms/sq.",
"(Ω/□) 2.",
"Film hardness: 7H EXAMPLE 2 The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, the content of ethylsilicate is increased for improving the film hardness;",
"and diacetonealcohol is added for improving the application characteristics.",
"The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.30 wt.",
"% ETHYL SILICATE 1.00 wt.",
"% ETHANOL 57.69 wt.",
"% ISOPROPANOL 10.00 wt.",
"% PURE WATER 25.00 wt.",
"% HYDROCHLORIC ACID (HCl, 35%) 0.01 wt.",
"% N-METHYL-2-PYRROLIDONE 2.00 wt.",
"% ETHYL CELLOSOLVE 2.00 wt.",
"% DIACETONEALCOHOL 2.00 wt.",
"% In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1.",
"Surface resistivity: 44*10 4 ohms/sq.",
"Film hardness: 8H EXAMPLE 3 The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, the content of PEDT/PSS is increased for improving the electroconductivity, and methylethylketone (MEK is added as a co-solvent for lowering the surface tension of the solution and improving the application characteristics.",
"The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.50 wt.",
"% ETHYL SILICATE 0.50 wt.",
"% ETHANOL 57.99 wt.",
"% ISOPROPANOL 10.00 wt.",
"% PURE WATER 25.00 wt.",
"% HYDROCHLORIC ACID (HCl, 35%) 0.01 wt.",
"% ETHYL CELLOSOLVE 3.00 wt.",
"% MEK (METHYLETHYLKETONE) 3.00 wt.",
"% In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1) Surface resistivity: 8*10 3 ohms/sq.",
"2) Film hardness: 7H EXAMPLE 4 The coating method is the same as that in EXAMPLE 1, but instead of ethyl silicate as a solvent in the electroconductive organic polymeric solution, butanol is used.",
"The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.30 wt.",
"% ETHANOL 60.70 wt.",
"% BUTANOL 10.00 wt.",
"% PURE WATER 25.00 wt.",
"% PROPYLENE GLYCOL MONO METHYL ESTER 2.00 wt.",
"% ETHYL CELLOSOLVE 2.00 wt.",
"% In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1) Surface resistivity: 4*10 3 ohms/sq.",
"2) Film hardness: 6H EXAMPLE 5 The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a solvent and a co-solvent are changed for improving the electroconductivity.",
"The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.30 wt.",
"% ETHYL SILICATE 0.50 wt.",
"% ETHANOL 58.19 wt.",
"% METHANOL 10.00 wt.",
"% PURE WATER 25.00 wt.",
"% HYDROCHLORIC ACID (HCl, 35%) 0.01 wt.",
"% N-METHYL-2-PYRROLIDONE 2.00 wt.",
"% BUTYL CELLOSOLVE 2.00 wt.",
"% ETHYL CELLOSOLVE 2.00 wt.",
"% In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1) Surface resistivity: 8*10 3 ohms/sq.",
"2) Film hardness: 7H EXAMPLE 6 The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a content of pure water, and a solvent and a co-solvent are changed for improving the application characteristic.",
"The constituents and the contents of the electroconductive organic polymeric solution or forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.30 wt.",
"% ETHYL SILICATE 0.50 wt.",
"% ETHANOL 58.19 wt.",
"% METHANOL 3.00 wt.",
"% ISOPROPYL ALCOHOL 17.00 wt.",
"% PURE WATER 15.00 wt.",
"% HYDROCHLORIC ACID (HCl, 35%) 0.01 wt.",
"% N-METHYL-2-PYRROLIDONE 2.00 wt.",
"% BUTYL CELLOSOLVE 2.00 wt.",
"% ETHYL CELLOSOLVE 2.00 wt.",
"% In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1) Surface resistivity: 1*10 4 ohms/sq.",
"2) Film hardness: 7H EXAMPLE 7 The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, contents of pure water and ethylsilicate, and a solvent and a co-solvent are changed.",
"The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.30 wt.",
"% ETHYL SILICATE 0.40 wt.",
"% ETHANOL 58.29 wt.",
"% METHANOL 10.00 wt.",
"% ISOPROPYL ALCOHOL 10.00 wt.",
"% PURE WATER 15.00 wt.",
"% HYDROCHLORIC ACID (HCl, 35%) 0.01 wt.",
"% N-METHYL-2-PYRROLIDONE 2.00 wt.",
"% PROPYLENE GLYCOL MONO METHYL ESTER 2.00 wt.",
"% ETHYL CELLOSOLVE 2.00 wt.",
"% In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1) Surface resistivity: 6*10 3 ohms/sq.",
"2) Film hardness: 7H EXAMPLE 8 The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a content of PEDT/PSS is decreased.",
"The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.10 ETHYL SILICATE 0.50 ETHANOL 70.39 ISOPROPANOL 10.00 PURE WATER 15.00 HYDROCHLORIC ACID (HCl, 35%) 0.01 N-METHYL-2-PYRROLIDONE 2.00 ETHYL CELLOSOLVE 2.00 In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1) Surface resistivity: 1*10 5 ohms/sq.",
"2) Film hardness: 8H EXAMPLE 9 The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a content of PEDT/PSS is remarkably decreased.",
"The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.005 ETHYL SILICATE 0.50 ETHANOL 80.485 ISOPROPANOL 10.00 PURE WATER 5.00 HYDROCHLORIC ACID (HCl, 35%) 0.01 N-METHYL-2-PYRROLIDONE 2.00 ETHYL CELLOSOLVE 2.00 In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1) Surface resistivity: 3*10 6 ohms/sq.",
"2) Film hardness: 8H EXAMPLE 10 The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a content of PEDT/PSS is extremely decreased.",
"The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.001 ETHYL SILICATE 0.50 ETHANOL 80.489 ISOPROPANOL 10.00 PURE WATER 5.00 HYDROCHLORIC ACID (HCl, 35%) 0.01 N-METHYL-2-PYRROLIDONE 2.00 ETHYL CELLOSOLVE 2.00 In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1) Surface resistivity: 4*10 3 ohms/sq.",
"2) Film hardness: 8H EXAMPLE 11 The coating method is the same as that in EXAMPLE 1, but in the electroconductive organic polymeric solution, a content of PEDT/PSS is remarkably increased.",
"The constituents and the contents of the electroconductive organic polymeric solution for forming the first coating layer 11 are as follows: CONSTITUENTS OF THE ELECTRO- CONTENT CONDUCTIVE ORGANIC POLYMERIC SOLUTION (wt.",
"%) PEDT/PSS 0.65 ETHYL SILICATE 0.50 ETHANOL 31.84 ISOPROPANOL 10.00 PURE WATER 53.00 HYDROCHLORIC ACID (HCl, 35%) 0.01 N-METHYL-2-PYRROLIDONE 2.00 ETHYL CELLOSOLVE 2.00 In the result from the example above, the surface resistivity and the film hardness by means of a pencil test are as follows: 1) Surface resistivity: 6*10 3 ohms/sq.",
"2) Film hardness: 5H As found from the above-described Examples 1 to 11, within the scope of the appended claims according to the present invention, it is realized to form, on the image display faceplate, the anti-static film 10 comprising a first coating layer 11 of high-electroconductivity containing an electroconductive organic polymeric component.",
"And, when the minimum of the ethyl silicate, i.e., only a binder is contained in the electroconductive first coating layer 11 , the electroconductivity can be maximized.",
"That is, compared with the examples 1 to 7 and 11, the examples 8, 9 and 10 shows the very high surface resistivity, thereby conspicuously lowering the electroconductivity.",
"Particularly, in less than 0.005 wt.",
"% of PEDT/PSS as shown in the example 10, the electroconductivity becomes abruptly lowered, while, PEDT/PSS of above 0.005 wt.",
"% is contained as shown in the example 11, the spin coating is difficult(the application characteristics become lowered and the film hardness becomes remarkably lowered due to the increase of the viscosity.",
"Therefore, the content of PEDT/PSS between 0.1 to 0.3 wt.",
"% is found to be proper as an electroconductive organic polymeric anti-static film for the image display faceplate.",
"Furthermore, the alkoxysilane solution is overcoating on the first coating layer 11 and permeated in the firs coating layer 11 , thereby making the silica film on the panel 2 and increasing the sticking strength.",
"Therefore, the first coating layer 11 becomes strongly attached to the panel 2 and the film hardness increased.",
"Thus, the anti-static film 10 having an excellent shield effect′ against electromagnetic radiation and the superior anti-static characteristics can be obtained.",
"Further, compared with the conventional metallic oxide coating, the manufacturing cost of the anti-static film 10 according to the present invention becomes lowered and its method simpler.",
"Also, deposition problem was not found, thereby making the coating on the exterior surface of the faceplate even without any spots.",
"The reason is understood to be that the solution used in the present invention does not comprise any inorganic slurry.",
"FIG. 3 is an enlarged sectional view similar, in part, showing an electroconductive organic polymeric anti-static film 20 formed on a general glass plate 2 ′ according to another embodiment of the present invention by means of the forementioned method.",
"In FIG. 3, the anti-static film 20 comprises a first coating layer 21 formed containing an electroconductive organic polymeric component and a second coating layer 22 of silica coating formed by being overcoated onto the first coating layer 21 , said anti-static film 20 having fine porosities 21 ′, as shown in FIG. 2 .",
"That is, the anti-static film 20 comprises the first coating layer 21 having fine porosities 21 ′ with an excellent electroconductivity, and the second coating layer 22 penetrates through the porosities 21 ′ of the first coating layer 21 when overcoated on the first coating layer 21 , thereby being adhered to at least the surface of the glass plate 2 ′.",
"Therefore, the second coating layer 22 is very high in the film hardness and the adhesive strength.",
"In examples for the glass plate 2 ′, using an electroconductive organic polymeric solution containing 0.005-0.5 wt.",
"% of polyethylenedioxythiophene which polystyrenesulphonate is doped to as the organic polymer of the first coating layer 21 , and using alkoxysilane Si(OR4(R is an alkyl group as a solution for making said second coating layer 12 , and similar to the above-described examples for the panel 2 , the coating structure of the electroconductive organic polymeric film is formed as shown in FIG. 3, and each surface resistivity and each film hardness in the pencil test are similar to those in each examples above for the panel 2 .",
"Therefore, except for an image display faceplate, the anti-static film 20 can be used for the general glass plate in which the anti-static characteristic is required like a monitor protective cover and also, for the shield effect against electromagnetic radiation or the anti-reflective effect.",
"Meanwhile, an anti-reflective layer 23 can be formed even in this embodiment for a more effective anti-reflection as shown in phantom line in FIG. 3 .",
"As understood from the above-described embodiments, the present invention enables an anti-static coating on a general glass plate having high electroconductivity or superior anti-static characteristics, very high sticking strength and film hardness, etc.",
", and at the lower manufacturing cost and in the simple manufacturing method.",
"It should be clear to one skilled in the art that the present invention can be altered and applied without any limitation to the aforementioned embodiments of the present invention and within the scope of the present invention's spirit."
] |
CROSSREFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/354,106 filed Jun. 11, 2010, which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention pertains to crutches, and more particularly to attachments for providing convenient means to carry items while using a crutch.
[0004] 2. Background of the Prior Art
[0005] Anyone who is deprived of the normal use of any of their bodily functions, even for a short period of time, knows that the performance of normal everyday activities, such as carrying a cup with a liquid, may be reduced or severely restricted during that time. One reason this may occur is that the individual is required to use their limbs to manipulate some type of artificial device to get around such as a wheelchair, cane, or crutches. The present invention is directed to an aid which is usable with such a device, in this case a crutch, which permits the user to manipulate the crutches and transport themselves while still performing the everyday simple activity of transporting a container having a liquid in it.
[0006] Productive adults are often injured during their leisure activities, such as in skiing accidents. In many cases, they suffer injuries requiring the temporary use of crutches for mobility. Crutches most commonly used during rehabilitation of such injuries are of the “Y” design. Such a crutch frame has two members that converge near the bottom and attach to a central leg member. The two frame members are spread apart at the top to support an under-arm brace. Horizontally opposing sets of holes in the frame members permit a handgrip to be attached between the frame members by a bolt and wing nut. Handgrip position is adjustable vertically for arm length by selecting the appropriate set of bolt holes. The central leg is similarly adjustable vertically in order to adapt the crutch to the user's height. There are at least four different types of “Y” crutches on the market, distinguishable by different frame cross-sections and materials of construction.
[0007] In order to continue performing their jobs, and even for everyday living, crutch users frequently have to carry a newspaper, documents, notepads, folders, mail, an address booklet, and similar articles found in both the home and business settings. Crutch users have considerable difficulty hand-carrying articles while simultaneously supporting themselves on a pair of crutches. Each crutch has a handgrip that the user grasps to both lean on and manipulate the crutch. While moving around on crutches, the user needs a method other than hand-carrying to transport even the smallest articles. A carrying device attached to one of the crutches can be of significant benefit to a productive adult, especially if it is capable of supporting articles found in the business setting, such as papers, folders, legal pads, and other predominantly thin, flat, and non-rigid articles.
[0008] Increasingly common in the business setting are metal 12 oz. beverage cans for single-service cold beverages, available from vending machines. With the popularity of vending machines in office complexes and other work facilities, a carrying device attachable to a crutch that not only supports business items, but which also supports an open 12 oz. beverage can, is highly desirable. Also of benefit is a carrying device which can be conveniently attached without tools to a wide variety of commercial crutch frames, and which is not as bulky as to limit the user's access through doorways or to knock things over.
[0009] Although carrying devices attachable to a crutch are known in the art, most are deficient in some respect. U.S. Pat. No. 3,429,541 to Herman, for example, shows a wire frame attachment that connects to handgrip adjusting holes below the handgrip, for carrying books, parcels, and other large objects. Although preferably made of resilient spring steel and coated with rubber, such a carrier has no way of clamping thin or small items because there is nothing to clamp against. The outermost end of the bent wire frame is centered between the two crutch frame members, requiring an article to be large and rigid so that both frame members resist the clamping force applied by the wire frame. A non-rigid article like a notepad would easily bend and avoid being clamped. Since the device is intended to be mounted in the handgrip holes below the handgrip, the lowermost position of the handgrip is unavailable. Mounting a carrying device above the handgrip is generally not feasible because articles then interfere with grasping the handgrip.
[0010] U.S. Pat. No. 3,985,148 to Cadman discloses a crutch carry-all attachment that has a hinged compartment for holding letters, papers, books, and the like. The compartment can be folded downward to carry a cup or beverage can. The attachment is bolted to the bottom leg of the crutch, which causes it to have limited usefulness when the leg is near its extreme extended or retracted position. In the leg extended position, the article being carried will be difficult to reach; in the leg retracted position, the attachment will interfere with the crutch handle.
[0011] U.S. Pat. No. 4,146,045 to Grant discloses a crutch carry-all attachment for holding small items such as papers, cigarettes, pens or pencils, and the like. The device is wedged between the side arms of the crutch and suffers from the same deficiencies as the Cadman patent.
[0012] U.S. Pat. No. 5,101,845 to Kravetz discloses a device that is attachable to the side of a crutch. The device interferes with the crutch handle to which the top portion is attached, and uses straps to attach the bottom portion to the sides of the crutch.
[0013] U.S. Pat. No. 5,803,327 to Nipper et al. discloses a cup holder that is attachable to the handle of a crutch. Like the Kravetz device, this appliance interferes with the crutch handle.
[0014] Thus, a need exists for a carrying attachment for a crutch that combines the features of convenience and versatility while avoiding interference with the operation of the crutch.
SUMMARY OF THE INVENTION
[0015] It is, therefore, an object of the present invention to provide a carrying attachment for a crutch that avoids the disadvantages of the prior art. It is another object of the invention is to provide a carrying attachment that can be attached to a crutch for holding articles in a convenient position to the crutch user. A related object is to provide a carrying attachment for a crutch that is inexpensive and of simplified construction so as to be commercially feasible.
[0016] In accordance with the above objects, a carrying attachment is disclosed having a front plate and a back plate detachably connected to each other. The front plate has a convex central portion and the back plate has a concave central portion. When the back plate and the front plate are connected, the convex central portion and the concave central portion form a channel that allows a crutch leg to move freely within the channel. In addition, the convex central portion of the front plate comprises a receptacle for an attachment piece. The front plate and the back plate each have a first end and a second end. The first end of the front plate and the first end of the back plate form a receptacle for a first side rail. The second end of the front plate and the second end of the back plate form a receptacle for a second side rail. Once connected, the receptacles formed by the first and second plates prevent the carrying attachment from sliding along the first side rail and the second side rail.
[0017] The carrying attachment disclosed herein can be used for holding letters, papers, books, and magazines. In some embodiments, the carrying attachment can also be used for holding a flashlight or water bottle. The carrying attachment can be attached to a crutch at any position and does not interfere with the adjustment of the leg or the use of the crutch handle. The carrying attachment may be constructed of a variety of materials such as, lightweight metal or plastic, among others.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and other features, aspects, and advantages of the present invention are considered in more detail, in relation to the following description of embodiments thereof shown in the accompanying drawings, in which:
[0019] FIG. 1 shows a perspective view of a front portion of a carrying attachment according to one embodiment of the present invention.
[0020] FIG. 2 shows a perspective view of a back portion of a carrying attachment according to one embodiment of the present invention.
[0021] FIG. 3 a shows a side view and FIG. 3 b shows a plan view of an attachment piece according to a particular embodiment of the present invention.
[0022] FIGS. 4-9 show various devices that can be used with a carrying attachment according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The invention summarized above may be better understood by referring to the following description, which should be read in conjunction with the claims and accompanying drawings in which like reference numbers are used for like parts. This description of an embodiment, set out below to enable one to practice an implementation of the invention, is not intended to limit the preferred embodiment, but to serve as a particular example thereof. Those skilled in the art should appreciate that they may readily use the conception and specific embodiments disclosed as a basis for modifying or designing other methods and systems for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent assemblies do not depart from the spirit and scope of the invention in its broadest form.
[0024] FIGS. 1 and 2 show a carrying attachment for a crutch, indicated generally as 10 . The carrying attachment 10 is adapted for use with a crutch 13 (partially shown) having a pair of side rails 15 , 16 (also referred to as the first side rail 15 and the second side rail 16 ) and a handle (not shown) extending between and secured to the side rails 15 , 16 . The side rails 15 , 16 converge inwardly at 18 , 19 to engage a leg 22 , which is secured therebetween. The crutch 13 is of conventional design and may vary in accordance with the needs of the user. Carrying attachment 10 comprises a front plate 25 and back plate 28 , made of strong, lightweight material, such as aluminum or plastic. The front plate 25 and the back plate 28 are detachably connected to each other by a plurality of fasteners.
[0025] In a preferred embodiment, the dimension of the width of the carrying attachment 10 is sized and configured to fit between the side rails 15 , 16 . Additionally, the front plate 25 and back plate 28 of carrying attachment 10 are shaped on their outer ends 30 , 31 and 33 , 34 , respectively, to conform to the shape of the side rails 15 , 16 . For example, in some embodiments, the ends 30 , 31 of front plate 25 and ends 33 , 34 of back plate 28 may be round to conform to round side rails 15 , 16 , while in other embodiments, the ends 30 , 31 of front plate 25 and ends 33 , 34 of back plate 28 may be rectangular to conform to square or rectangular side rails 15 , 16 . The first end 30 of the front plate 25 and the first end 33 of the back plate 28 come together forming a receptacle for the first side rail 15 when the front plate 25 and the back plate 28 are detachably connected to each other. The receptacle formed squeezes the first side rail 15 of the crutch 13 . Similarly, the second end 31 of the front plate 25 and the second end 34 of the back plate 28 come together forming a receptacle for the second side rail 16 when the front plate 25 and the back plate 28 are detachably connected to each other. The receptacle formed squeezes the second side rail 16 of the crutch 13 .
[0026] Typically, the front and back plates 25 , 28 may be approximately 5½ inches wide and approximately 2 inches tall. Other sizes can be used, for example, in one further embodiment, the front and back plates 25 , 28 may be up to 3 inches tall and 5½ inches wide. The front plate 25 has a convex central portion 38 that extends away from the crutch 13 and the back plate 28 . The back plate 28 has a concave central portion 39 that extends away from the crutch 13 and the front plate 25 . When the front plate 25 and the back plate 28 are detachably connected, the convex central portion 38 and the concave central portion 39 form a channel that provides sufficient clearance for the leg 22 to pass between the front and back plates 25 , 28 .
[0027] The carrying attachment 10 is mounted to the crutch 13 by a plurality of fasteners 36 , such as screws, bolts and wing nuts, bolts and nuts, or other appropriate device that allows the plates to be attached to one another. In one preferred embodiment, the plates 25 , 28 are attached to one another by two fasteners 36 . In a further embodiment, the plates 25 , 28 are attached to one another by four fasteners 36 . Preferably, the screws 36 extend from the back plate 28 into the front plate 25 enough to engage the plates 25 , 28 and squeeze the ends 30 , 31 , 33 , 34 against the side rails 15 , 16 , and prevent the carrying attachment 10 from sliding along the side rails 15 , 16 .
[0028] The convex central portion 38 of front plate 25 includes a receptacle 40 for an attachment piece 44 . The receptacle 40 allows the attachment piece 44 to be connected to the carrying attachment 10 . The attachment piece has an attachment element 47 that connects the attachment piece 44 to the receptacle 40 on the carrying attachment 10 . In one preferred embodiment, the receptacle 40 includes an elongate slot 41 into which the attachment element 47 fits to secure the attachment piece 44 to the carrying attachment 10 . FIGS. 3 a and 3 b show an attachment piece 44 having one or more attachment elements 47 , such as buttons, nuts and bolts, wing nuts and bolts and other devices that allow attachment of the attachment element 47 to the front plate 25 . The buttons 47 are sized and configured to slidably engage in the elongate slot 41 .
[0029] The attachment piece 44 provides the backing for a carrying element 50 that connects a variety of implements to the crutch, such as shown in FIGS. 4-9 . For example, FIG. 4 the carrying element 50 allows for attachment of a flashlight that may have a swivel connection to the elongate slot 41 . In FIG. 5 , the carrying element 50 fits a water bottle with a closable top in a wire holder that can be connected by an attachment piece 44 to the elongate slot 41 . FIG. 6 shows a carrying element 50 in the form of a mug holder that can be connected by an attachment piece 44 to the elongate slot 41 . For mugs and cups, it is preferred that the mug or cup has a spill proof top. In FIG. 7 the carrying element 50 is a pair of hooks that can be hingedly mounted to an attachment piece 44 that can slidably engage the elongate slot 41 . For such hooks, it is preferred that the hooks can fold flush against the attachment piece 44 when not in use. In a preferred embodiment, such hooks can be held against the attachment piece by magnetic force. FIG. 8 shows the attachment piece 44 comprising a protective laptop computer case. Preferably, such case comprises a plastic enclosure having a padded inner face. Additionally, for a computer case, one end of the enclosure should remain open to allow the computer to slide in. FIG. 9 shows the attachment piece 44 comprising a bag or purse having a closable top.
[0030] In some embodiments, the elongate slot 41 may include a detent 42 or releasable locking mechanism to hold the attachment piece when engaged in the elongate slot 41 . In other preferred embodiments, that attachment element 47 may be secured to the front plate 25 by a lock, which prevents the attachment element 47 from sliding out of the elongate slot 41 .
[0031] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It should be understood, therefore, that the invention may be practiced otherwise than as specifically set forth herein. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. | A carrying attachment is disclosed for holding letters, papers, books, and magazines. In some embodiments, the carrying attachment can be used for holding a flashlight, water bottle, etc. The carrying attachment can be attached to a crutch at any position and does not interfere with the adjustment of the leg or the use of the crutch handle. The carrying attachment may be constructed of a variety of materials such as, lightweight metal or plastic, among others. | Identify and summarize the most critical features from the given passage. | [
"CROSSREFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/354,106 filed Jun. 11, 2010, which is incorporated herein by reference in its entirety.",
"BACKGROUND OF THE INVENTION [0002] 1.",
"Field of the Invention [0003] This invention pertains to crutches, and more particularly to attachments for providing convenient means to carry items while using a crutch.",
"[0004] 2.",
"Background of the Prior Art [0005] Anyone who is deprived of the normal use of any of their bodily functions, even for a short period of time, knows that the performance of normal everyday activities, such as carrying a cup with a liquid, may be reduced or severely restricted during that time.",
"One reason this may occur is that the individual is required to use their limbs to manipulate some type of artificial device to get around such as a wheelchair, cane, or crutches.",
"The present invention is directed to an aid which is usable with such a device, in this case a crutch, which permits the user to manipulate the crutches and transport themselves while still performing the everyday simple activity of transporting a container having a liquid in it.",
"[0006] Productive adults are often injured during their leisure activities, such as in skiing accidents.",
"In many cases, they suffer injuries requiring the temporary use of crutches for mobility.",
"Crutches most commonly used during rehabilitation of such injuries are of the “Y”",
"design.",
"Such a crutch frame has two members that converge near the bottom and attach to a central leg member.",
"The two frame members are spread apart at the top to support an under-arm brace.",
"Horizontally opposing sets of holes in the frame members permit a handgrip to be attached between the frame members by a bolt and wing nut.",
"Handgrip position is adjustable vertically for arm length by selecting the appropriate set of bolt holes.",
"The central leg is similarly adjustable vertically in order to adapt the crutch to the user's height.",
"There are at least four different types of “Y”",
"crutches on the market, distinguishable by different frame cross-sections and materials of construction.",
"[0007] In order to continue performing their jobs, and even for everyday living, crutch users frequently have to carry a newspaper, documents, notepads, folders, mail, an address booklet, and similar articles found in both the home and business settings.",
"Crutch users have considerable difficulty hand-carrying articles while simultaneously supporting themselves on a pair of crutches.",
"Each crutch has a handgrip that the user grasps to both lean on and manipulate the crutch.",
"While moving around on crutches, the user needs a method other than hand-carrying to transport even the smallest articles.",
"A carrying device attached to one of the crutches can be of significant benefit to a productive adult, especially if it is capable of supporting articles found in the business setting, such as papers, folders, legal pads, and other predominantly thin, flat, and non-rigid articles.",
"[0008] Increasingly common in the business setting are metal 12 oz.",
"beverage cans for single-service cold beverages, available from vending machines.",
"With the popularity of vending machines in office complexes and other work facilities, a carrying device attachable to a crutch that not only supports business items, but which also supports an open 12 oz.",
"beverage can, is highly desirable.",
"Also of benefit is a carrying device which can be conveniently attached without tools to a wide variety of commercial crutch frames, and which is not as bulky as to limit the user's access through doorways or to knock things over.",
"[0009] Although carrying devices attachable to a crutch are known in the art, most are deficient in some respect.",
"U.S. Pat. No. 3,429,541 to Herman, for example, shows a wire frame attachment that connects to handgrip adjusting holes below the handgrip, for carrying books, parcels, and other large objects.",
"Although preferably made of resilient spring steel and coated with rubber, such a carrier has no way of clamping thin or small items because there is nothing to clamp against.",
"The outermost end of the bent wire frame is centered between the two crutch frame members, requiring an article to be large and rigid so that both frame members resist the clamping force applied by the wire frame.",
"A non-rigid article like a notepad would easily bend and avoid being clamped.",
"Since the device is intended to be mounted in the handgrip holes below the handgrip, the lowermost position of the handgrip is unavailable.",
"Mounting a carrying device above the handgrip is generally not feasible because articles then interfere with grasping the handgrip.",
"[0010] U.S. Pat. No. 3,985,148 to Cadman discloses a crutch carry-all attachment that has a hinged compartment for holding letters, papers, books, and the like.",
"The compartment can be folded downward to carry a cup or beverage can.",
"The attachment is bolted to the bottom leg of the crutch, which causes it to have limited usefulness when the leg is near its extreme extended or retracted position.",
"In the leg extended position, the article being carried will be difficult to reach;",
"in the leg retracted position, the attachment will interfere with the crutch handle.",
"[0011] U.S. Pat. No. 4,146,045 to Grant discloses a crutch carry-all attachment for holding small items such as papers, cigarettes, pens or pencils, and the like.",
"The device is wedged between the side arms of the crutch and suffers from the same deficiencies as the Cadman patent.",
"[0012] U.S. Pat. No. 5,101,845 to Kravetz discloses a device that is attachable to the side of a crutch.",
"The device interferes with the crutch handle to which the top portion is attached, and uses straps to attach the bottom portion to the sides of the crutch.",
"[0013] U.S. Pat. No. 5,803,327 to Nipper et al.",
"discloses a cup holder that is attachable to the handle of a crutch.",
"Like the Kravetz device, this appliance interferes with the crutch handle.",
"[0014] Thus, a need exists for a carrying attachment for a crutch that combines the features of convenience and versatility while avoiding interference with the operation of the crutch.",
"SUMMARY OF THE INVENTION [0015] It is, therefore, an object of the present invention to provide a carrying attachment for a crutch that avoids the disadvantages of the prior art.",
"It is another object of the invention is to provide a carrying attachment that can be attached to a crutch for holding articles in a convenient position to the crutch user.",
"A related object is to provide a carrying attachment for a crutch that is inexpensive and of simplified construction so as to be commercially feasible.",
"[0016] In accordance with the above objects, a carrying attachment is disclosed having a front plate and a back plate detachably connected to each other.",
"The front plate has a convex central portion and the back plate has a concave central portion.",
"When the back plate and the front plate are connected, the convex central portion and the concave central portion form a channel that allows a crutch leg to move freely within the channel.",
"In addition, the convex central portion of the front plate comprises a receptacle for an attachment piece.",
"The front plate and the back plate each have a first end and a second end.",
"The first end of the front plate and the first end of the back plate form a receptacle for a first side rail.",
"The second end of the front plate and the second end of the back plate form a receptacle for a second side rail.",
"Once connected, the receptacles formed by the first and second plates prevent the carrying attachment from sliding along the first side rail and the second side rail.",
"[0017] The carrying attachment disclosed herein can be used for holding letters, papers, books, and magazines.",
"In some embodiments, the carrying attachment can also be used for holding a flashlight or water bottle.",
"The carrying attachment can be attached to a crutch at any position and does not interfere with the adjustment of the leg or the use of the crutch handle.",
"The carrying attachment may be constructed of a variety of materials such as, lightweight metal or plastic, among others.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0018] The above and other features, aspects, and advantages of the present invention are considered in more detail, in relation to the following description of embodiments thereof shown in the accompanying drawings, in which: [0019] FIG. 1 shows a perspective view of a front portion of a carrying attachment according to one embodiment of the present invention.",
"[0020] FIG. 2 shows a perspective view of a back portion of a carrying attachment according to one embodiment of the present invention.",
"[0021] FIG. 3 a shows a side view and FIG. 3 b shows a plan view of an attachment piece according to a particular embodiment of the present invention.",
"[0022] FIGS. 4-9 show various devices that can be used with a carrying attachment according to an embodiment of the present invention.",
"DETAILED DESCRIPTION OF THE INVENTION [0023] The invention summarized above may be better understood by referring to the following description, which should be read in conjunction with the claims and accompanying drawings in which like reference numbers are used for like parts.",
"This description of an embodiment, set out below to enable one to practice an implementation of the invention, is not intended to limit the preferred embodiment, but to serve as a particular example thereof.",
"Those skilled in the art should appreciate that they may readily use the conception and specific embodiments disclosed as a basis for modifying or designing other methods and systems for carrying out the same purposes of the present invention.",
"Those skilled in the art should also realize that such equivalent assemblies do not depart from the spirit and scope of the invention in its broadest form.",
"[0024] FIGS. 1 and 2 show a carrying attachment for a crutch, indicated generally as 10 .",
"The carrying attachment 10 is adapted for use with a crutch 13 (partially shown) having a pair of side rails 15 , 16 (also referred to as the first side rail 15 and the second side rail 16 ) and a handle (not shown) extending between and secured to the side rails 15 , 16 .",
"The side rails 15 , 16 converge inwardly at 18 , 19 to engage a leg 22 , which is secured therebetween.",
"The crutch 13 is of conventional design and may vary in accordance with the needs of the user.",
"Carrying attachment 10 comprises a front plate 25 and back plate 28 , made of strong, lightweight material, such as aluminum or plastic.",
"The front plate 25 and the back plate 28 are detachably connected to each other by a plurality of fasteners.",
"[0025] In a preferred embodiment, the dimension of the width of the carrying attachment 10 is sized and configured to fit between the side rails 15 , 16 .",
"Additionally, the front plate 25 and back plate 28 of carrying attachment 10 are shaped on their outer ends 30 , 31 and 33 , 34 , respectively, to conform to the shape of the side rails 15 , 16 .",
"For example, in some embodiments, the ends 30 , 31 of front plate 25 and ends 33 , 34 of back plate 28 may be round to conform to round side rails 15 , 16 , while in other embodiments, the ends 30 , 31 of front plate 25 and ends 33 , 34 of back plate 28 may be rectangular to conform to square or rectangular side rails 15 , 16 .",
"The first end 30 of the front plate 25 and the first end 33 of the back plate 28 come together forming a receptacle for the first side rail 15 when the front plate 25 and the back plate 28 are detachably connected to each other.",
"The receptacle formed squeezes the first side rail 15 of the crutch 13 .",
"Similarly, the second end 31 of the front plate 25 and the second end 34 of the back plate 28 come together forming a receptacle for the second side rail 16 when the front plate 25 and the back plate 28 are detachably connected to each other.",
"The receptacle formed squeezes the second side rail 16 of the crutch 13 .",
"[0026] Typically, the front and back plates 25 , 28 may be approximately 5½ inches wide and approximately 2 inches tall.",
"Other sizes can be used, for example, in one further embodiment, the front and back plates 25 , 28 may be up to 3 inches tall and 5½ inches wide.",
"The front plate 25 has a convex central portion 38 that extends away from the crutch 13 and the back plate 28 .",
"The back plate 28 has a concave central portion 39 that extends away from the crutch 13 and the front plate 25 .",
"When the front plate 25 and the back plate 28 are detachably connected, the convex central portion 38 and the concave central portion 39 form a channel that provides sufficient clearance for the leg 22 to pass between the front and back plates 25 , 28 .",
"[0027] The carrying attachment 10 is mounted to the crutch 13 by a plurality of fasteners 36 , such as screws, bolts and wing nuts, bolts and nuts, or other appropriate device that allows the plates to be attached to one another.",
"In one preferred embodiment, the plates 25 , 28 are attached to one another by two fasteners 36 .",
"In a further embodiment, the plates 25 , 28 are attached to one another by four fasteners 36 .",
"Preferably, the screws 36 extend from the back plate 28 into the front plate 25 enough to engage the plates 25 , 28 and squeeze the ends 30 , 31 , 33 , 34 against the side rails 15 , 16 , and prevent the carrying attachment 10 from sliding along the side rails 15 , 16 .",
"[0028] The convex central portion 38 of front plate 25 includes a receptacle 40 for an attachment piece 44 .",
"The receptacle 40 allows the attachment piece 44 to be connected to the carrying attachment 10 .",
"The attachment piece has an attachment element 47 that connects the attachment piece 44 to the receptacle 40 on the carrying attachment 10 .",
"In one preferred embodiment, the receptacle 40 includes an elongate slot 41 into which the attachment element 47 fits to secure the attachment piece 44 to the carrying attachment 10 .",
"FIGS. 3 a and 3 b show an attachment piece 44 having one or more attachment elements 47 , such as buttons, nuts and bolts, wing nuts and bolts and other devices that allow attachment of the attachment element 47 to the front plate 25 .",
"The buttons 47 are sized and configured to slidably engage in the elongate slot 41 .",
"[0029] The attachment piece 44 provides the backing for a carrying element 50 that connects a variety of implements to the crutch, such as shown in FIGS. 4-9 .",
"For example, FIG. 4 the carrying element 50 allows for attachment of a flashlight that may have a swivel connection to the elongate slot 41 .",
"In FIG. 5 , the carrying element 50 fits a water bottle with a closable top in a wire holder that can be connected by an attachment piece 44 to the elongate slot 41 .",
"FIG. 6 shows a carrying element 50 in the form of a mug holder that can be connected by an attachment piece 44 to the elongate slot 41 .",
"For mugs and cups, it is preferred that the mug or cup has a spill proof top.",
"In FIG. 7 the carrying element 50 is a pair of hooks that can be hingedly mounted to an attachment piece 44 that can slidably engage the elongate slot 41 .",
"For such hooks, it is preferred that the hooks can fold flush against the attachment piece 44 when not in use.",
"In a preferred embodiment, such hooks can be held against the attachment piece by magnetic force.",
"FIG. 8 shows the attachment piece 44 comprising a protective laptop computer case.",
"Preferably, such case comprises a plastic enclosure having a padded inner face.",
"Additionally, for a computer case, one end of the enclosure should remain open to allow the computer to slide in.",
"FIG. 9 shows the attachment piece 44 comprising a bag or purse having a closable top.",
"[0030] In some embodiments, the elongate slot 41 may include a detent 42 or releasable locking mechanism to hold the attachment piece when engaged in the elongate slot 41 .",
"In other preferred embodiments, that attachment element 47 may be secured to the front plate 25 by a lock, which prevents the attachment element 47 from sliding out of the elongate slot 41 .",
"[0031] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described.",
"Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept.",
"It should be understood, therefore, that the invention may be practiced otherwise than as specifically set forth herein.",
"The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive."
] |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority of German patent applications Nos. 10 2008 064 205.3 filed on Dec. 22, 2008 and 10 2009 011 204.9 filed on Mar. 4, 2009. All prior applications are herein incorporated by reference in their entirety.
FIELD OF THE INVENTION
The present invention relates to a method and a device for cleaning soiled instrument channels, in particular for the efficient cleaning of channels in medical instruments.
BACKGROUND OF THE INVENTION
If a reusable medical instrument is being used with a patient, then it requires cleaning after its application to the patient. Cleaning of instrumental channels of medical products is particularly difficult.
German patent application DE 2006 001 076 A1 discloses a cleaning brush composed of a long, flexible carrier element and a digitally attached brush head. A section of the carrier element extends beyond the bridge head on its digital side. Lengthening the rod-shaped carrier element avoids the scattering of liquids by a swinging or springing motion by the carrier element. Thanks to the distribution of impure materials in the instrument channel by the brush, cleaning with this cleaning brush does not yield a satisfactory cleaning result.
European patent application EP 1105061 B1 discloses a method and device for cleaning a soiled lumen of an endoscope, by which the impure materials are distributed uniformly inside the instrument channel by pulling and pushing the cleaning device in the instrument channel. Thereafter, this film uniformly distributed in the channel is treated with an enzymatic cleaning liquid. In this case the cleaning device does not serve to remove substances that are to be expelled from the instrument channel, but rather serves for uniform distribution to improve the subsequent treatment with an enzymatic cleaning liquid. The cleaning effect is not sufficient.
The design patent DE 20200700793 U1 discloses a cleaning wick for an instrument channel of a medical instrument. It shows a wick that comprises an adhesive flocking in a partial area. The fibers consist of synthetic material or else natural fibers. When using this cleaning device, the total soiling is distributed after a single pass through the instrument channel, upon withdrawing the cleaning device in the instrument channel. It is necessary to perform a subsequent treatment with cleaning fluid or a repeated cleaning after washing the fibers of the cleaning device.
It is the object of the invention to disclose a method and a device for cleaning medical instrument channels that produce an efficient, good cleaning result.
SUMMARY OF THE INVENTION
The present invention fulfills this object by means of the cleaning device with a rod-shaped carrier element and at least one cleaning element connected with the carrier element, where the cleaning element can be detached from the carrier element, and/or a cleaning method including the steps of moving the cleaning device in the axial direction in the instrument channel up to an end point, so that after reaching the end point the cleaning device is moved outward in the opposite axial direction in the instrument channel and a detachable cleaning element is separated from the carrier element and then is no longer part of the cleaning process of the previously cleaned instrument channel. Advantageous adaptations of the invention are given in the subsidiary claims.
The cleaning device in accordance with the present invention contains a rod-shaped carrier element with cleaning elements. The cleaning elements show at least one fixed cleaning element and in addition at least one detachable cleaning element that can be slid axially on the carrier element. As a result of this multi-partite structure of the cleaning elements on the rod-shaped carrier element, any distribution of impurities in the instrument channel can be reduced as much as possible. The multiform structure of the cleaning element serves the purpose of releasing a detachable element positioned on a fixed cleaning element—said detachable element picking up or combining the majority of impurities by pushing the cleaning device forward through the instrument channel—after the typically one-time motion in the axial direction of the instrument channel up to an end point.
In the subsequent withdrawal of the cleaning device through the instrument channel, this detachable cleaning element is released from the carrier element and is no longer part of the ensuing typical cleaning process. In this manner, any distribution of impurities in the instrument channel, especially those adhering to the detachable cleaning element, is reduced, because a major portion of the impurities are separated from the cleaning device by the detachable cleaning element. Cleaning with the present cleaning device is therefore more efficient and reduces the impurities in the already cleaned instrument channel.
Through the releasing of the detachable cleaning element from the carrier element, there is the additional advantage that on removing the cleaning device from the instrument channel, the extending carrier element on which the distally positioned detachable cleaning element is inserted, prevents any uncontrolled spraying of cleaning fluids and the like that may have been used, by its protrusion, during removal of the remaining cleaning device from the instrument channel. In this manner it is possible to reduce any spraying contamination of the surroundings with possibly infectious material.
The terms “detachable” and “fixed,” as used in the foregoing and hereafter, indicate various detaching and fixing possibilities between the cleaning element and the carrier element. In this respect, the term “detachable” is understood to mean a type of connection that allows a sliding of the cleaning element on the carrier element and thus a separation from the carrier element, for instance by slipping or pushing down the cleaning element from the carrier element. Alternatively, the cleaning element, with a part of the carrier element, can also be separated from the rest of the carrier element at a foreseen cut-off point, for instance by means of breaking at a predetermined fracture point or by severing it at a defined cut-off point. The term “fixed” designates a connection that does not allow any sliding of the cleaning element on the carrier element because of the axial motion of the instrument channel. The connection between the cleaning element and the carrier element is preserved during the cleaning process.
In a particular embodiment, at least one cleaning element is connected with the carrier element and is configured so that it can be separated from the carrier element.
A renewed distribution of the impurities, in particular, that are connected to the detachable cleaning element is reduced in the instrument channel because a great portion of the impurities was separated from the cleaning device through the separation of the cleaning element from the cleaning device. A cleaning is extremely efficient and reduces the impurities in the already cleaned instrument channel. This configuration offers the additional advantage that the cleaning device itself shows a high cleaning quality because of the separation of the cleaning element from the carrier element.
One embodiment of the present invention shows that at least one detachable cleaning element is positioned distally on the carrier element and at least one fixed cleaning element is positioned proximally to said first element.
This has the advantage that upon withdrawing the cleaning device, the detachable cleaning element can detach itself from the carrier element and in this manner the impurities already collected on the detachable cleaning element are not distributed in the already cleaned instrument channel. The cleaning of the instrument channel is therefore more efficient and allows a better cleaning result.
Preferably, the detachable cleaning element is attached to the carrier element by a lubricious connection. It is possible not to push the detachable cleaning element onto the carrier element, but rather to slide it through the instrument channel with the carrier element and the fixed cleaning element. Preferably, however, it is advisable to equip the detachable cleaning element with a bored aperture, through which the carrier element can be pinned onto the detachable cleaning element in sliding fashion. This allows the detachable cleaning element to be slid uniformly through the channel and prevents any irregular deforming of the cleaning element.
It has been demonstrated, in particular, that part of the carrier element can be detached with at least one cleaning element by means of a cut-off point provided on the distal end of the carrier element.
This embodiment has the advantage that the soiled cleaning element, after it emerges from the instrument channel, can be detached by the carrier element independently of its shape, its material, and its stretch properties, and in this way the impurities already collected and no longer distributed in the instrument channel. The cleaning of the instrument channels is therefore far more efficient.
In a particular embodiment, several fixed cleaning elements are secured on the rod-shaped carrier element such as to allow an intermediate space with respect to one another. These inventive intermediate spaces have the advantage that within these spaces it is also possible to transport larger collections of impurities, which can fall away or can be manually removed after one passage of the cleaning device through the instrument channel with the detachable cleaning element. In addition, they allow a spreading of the cleaning elements into the instrument channel in the axial direction, leading to an improved cleaning result. Preferably the carrier element is provided with a stop, which restricts the slidability of the cleaning element on the carrier element.
The stop provided for limiting the slidability of the cleaning element prevents the cleaning element from detaching itself from the carrier element during the cleaning process and remaining stuck in the instrument channel. This manner of fixing a cleaning element on the carrier element has the additional advantage that the user can assemble his cleaning device in modular fashion, for instance by making possible the limiting of the slidability of the cleaning elements with synthetic elements, which he can apply distally from the proximal and/or distal end of the cleaning element.
It has been shown that the area of the carrier element on which the cleaning element is fixed has, because of the addition or removal of material, the property of fulfilling the purpose of a fixing of the cleaning elements. For instance, applying a metallic structure to the area of the carrier element can enlarge the diameter of the carrier element at this spot, so that a cleaning element that includes a borehole with the diameter of the rest of the carrier element and is pushed onto the rod-shaped carrier element is fixed. An adhesive connection constitutes another preferred possibility for fixing the cleaning element on the carrier element.
In a preferred configuration for fixing a cleaning element on the carrier element, areas for fixing onto the carrier element with a thread are provided and fixed thereto so that the cleaning elements to be fixed can be screwed on. This configuration offers the advantage that the carrier element can be prepared anew after its use and, once provided with new cleaning elements, can be applied again to the cleaning of instrument channels. A carrier element that has been prepared anew can be selected as more worthwhile in its material properties and in its design, because it can be used repeatedly for the cleaning of diverse channels. The combination of the cleaning elements as a disposable article and the carrier element as a reusable article therefore offers a considerably more valuable material configuration and likewise cost reduction. During the cleaning process the material can be put under greater pressure through the use of more valuable materials, leading to a better, more efficient cleaning result.
The cleaning elements are preferably constructed of a material with compressible properties. A material with compressible properties, preferably with felt-type properties, allows compression of the cleaning element upon insertion into the instrument channel. In this manner the cleaning element is compressed upon shoving the cleaning device onto the instrument channel. This allows a higher abrasive property of the cleaning elements. As a result, greater impurities for instance, as well as hardened substances adhering to the instrument channel, can be removed better. By using the compressible material, the spraying of cleaning liquid and collected impurities in the instrument channel upon removal of the cleaning device from the instrument channel can be avoided because the cleaning elements stretch more uniformly upon removal because of the compressible material.
In an especially preferred embodiment, at least one cleaning element can take up and exude a liquid. As a result of the combination of the cleaning device with a liquid, in particular water or a liquid with cleansing properties such as by using enzymatic substances, the cleaning process can be clearly optimized. Preferably not all cleaning elements are provided with a liquid, so that the other cleaning elements on the carrier element can absorb the liquids from the instrument channel. In an additional embodiment the diameter of the cleaning elements is selected so that it is larger than the smallest and largest diameter of the instrument channel that is to be cleaned.
If the cleaning elements were to have a smaller diameter than the smallest and largest diameter of the instrument channel, then upon sliding the cleaning device through the instrument channel in the axial direction, the cleaning elements would not continually touch and clean the channel interior.
A larger diameter of the cleaning elements than the smallest and largest diameter of the instrument channels, which can also vary in its diameter, therefore prevents a back-and-forth motion of the carrier element diagonally to the instrument channel during the cleaning process by specialized personnel, because the material of the cleaning elements all around the entire channel wall is pressed together. In this manner in particular it is possible to prevent damage, especially by the carrier element in the instrument channel, because the cleaning device is moved uniformly through the instrument channel and an efficient cleaning result is achieved.
It has been shown in particular that the outer form of the cross-section of the cleaning elements corresponds to the cross-section of the instrument channel that is to be cleaned.
This has the advantage that by means of the same configuration a uniform compression of the material of the cleaning elements, as well as an easier insertion and sliding of the cleaning device through the instrument channel, can be realized. As a result of this arrangement, a lower use of force needs to be applied in moving the cleaning device back and forth in the instrument channel, which clearly reduces the risk of damage inside the instrument channel by erroneous operation and makes the cleaning process more comfortable for the specialized personnel. In addition, owing to this configuration, depending on the choice of the proportion of the dimensions of the cross-section of the instrument channel and cleaning elements to one another, the abrasive property of the cleaning device can be modulated and the cleaning needs can be taken into account.
In a particular embodiment of the cleaning device, the degree of hardness of the cleaning elements varies along the rod-shaped carrier element.
Owing to this diverse degree of hardness, the cleaning device can be used both for combining and removing larger impurities as well as for absorbing existing liquids that are found increasingly in the instrument channel after the use of a medical instrument on the patient. In this process the cleaning elements with the lower degree of hardness absorb the liquids and impurities present in the instrument channel, while the cleaning elements whose materials show a higher degree of hardness because of their higher abrasive properties, remove and combine together larger and more adherent substances from the instrument channel.
According to a particularly preferred embodiment, the hardness properties of the cleaning elements decrease in the direction from proximal to distal on the carrier element.
In this particular configuration of the arrangement of the cleaning elements with various hardness properties, there is the advantage that the cleaning device, along with the absorption of liquids and the collection of impurities, can be more easily inserted into the instrument channel. The arrangement of the cleaning elements of diverse hardness properties on the carrier element can, however, also be increasing in the reverse direction.
In one embodiment, at least one cleaning element on the carrier element has a hardness gradient of compressible material that varies in the direction from proximal to distal.
This gradient leads to a particularly good cleaning result, even if the carrier element is equipped only with few cleaning elements. Thus, for instance, only with a cleaning element that is very long in the axial direction can the impurities in the instrument channel be efficiently combined together.
Preferably the cleaning elements on the carrier element are of diverse materials.
The design of the cleaning elements on a carrier element with diverse materials allows the adaptation of the cleaning device to the diverse requirements that frequently arise in practice. Thus, for instance, a device can be selected for the cleaning of an irrigation channel that has cleaning elements which consist of an elastic synthetic material whose sides are provided with a blade edge. The combination of cleaning elements with felt-type properties with cleaning elements of synthetic material, for instance a spongy material, is also very effective especially when using cleaning liquids.
In a particular embodiment, the cleaning elements on a carrier element have different diameters. In a special configuration of this model, the diameters of the cleaning elements are positioned in declining order from the proximal to the distal side.
As a result the insertion of the cleaning device into the instrument channel and thus the handling is simplified, but because of the decreasing diameters of the cleaning elements from proximal to distal side, the cleaning elements decreasing from proximal to distal side are compressed to varying degrees, so that because of this configuration the strongly compressed cleaning elements show a stronger combining or abrasive function and the less compressed cleaning elements show instead an increasing function. The arrangement of the diverse diameters of the cleaning elements can also vary, however, or else can be selected as decreasing from the distal to the proximal side. It has proven especially beneficial to optimize the slidability of the distally situated cleaning elements on the carrier element by coating the area of the carrier element that is situated distally to the fixed cleaning element preferably with an especially lubricious surface, for instance with Teflon, or by making it from a corresponding low-friction material.
The rigid rod-shaped carrier element can also be coated with a low-friction synthetic material, such as polytetrafluorethylene (PTFE), or with another lubricious material such as Teflon.
Such a low-friction realization of the surface of the rod-shaped carrier element facilitates the removal of the detachable cleaning element from the carrier element after a single passage through the instrument channel and in addition, upon contact of the carrier element with the instrument channel that is to be cleaned, prevents damage to the channel of the instrument. It has been shown that it is advantageous to choose for the carrier element a rigid material, in particular steel. The term “rigid,” as used here, is understood to mean a material that has a high buckling resistance, stability, and cannot be deformed. This makes possible a very reliable and safe cleaning, especially for straight, rigid endoscopes. Depending on the size of the cross-section, the material can also have elastic properties or can be made of an elastic material so that the cleaning device is well adapted to the shape of the instrument channel and also can be used for cleaning flexible and possibly bent medical instruments. An additional possibility is to segment the rod-shaped carrier element to reach various areas with elastic and deformable properties and to be able to clean especially efficient, difficult channel geometries.
In a preferred embodiment, the carrier element is made of a solid material. If the rod-shaped carrier element consists of solid material, then despite small cross-section surfaces, which are often used in cleaning channels of small instruments with small diameters, it can have very high stability and resistance to buckling. In particular, the solid material also offers the advantage that no impurities can collect in the carrier element that, in turn, need to be cleaned with a cleaning device if the carrier element takes the form of a reprocessed product.
It has been shown in particular that the carrier element comprises a phase at its ends.
A phase at the ends of the carrier element has the advantage that damage that can be caused by the cleaning device in the instrument channel, for instance by grazing along the channel surface, can be avoided and in addition that introduction of the cleaning device into the instrument channel is supported.
Preferably a marker is provided on the carrier element constituting a measurement for the insertion depth of the cleaning device in the instrument channel and representing the desired end position of the cleaning device in the instrument channel.
This has the advantage that all parts of the instrument channel are reliably cleaned and the marker enables the user to clean the instrument channel completely without moving the device unnecessarily far outside the channel in the distal direction. Thus the detachable cleaning element, corresponding to the position of the marker, for instance, can be pushed out of the instrument channel only so far that part of the cleaning element remains inside the instrument channel and is fixed in such a way that it can, however, be manually removed from the channel. The detachable cleaning element, in this manner, does not fall uncontrollably out of the instrument channel, and an uncontrolled distribution of collected substances into the environment by the detachable cleaning element is avoided. Alternatively, the position of the marker can also be selected in such a way that the detachable cleaning element extends entirely out of the channel in the distal direction and becomes detached when pulled back. The handling of the cleaning device is therefore further improved by this marker.
It has been shown to be advantageous to provide for the cleaning device a container for inserting contaminated cleaning elements with a closeable opening. Through this opening it is possible for at least one cleaning element of the cleaning device to be brought into container interior space. In addition, according to the invention, the container is provided with a device for detaching at least one cleaning element from a carrier element in the container interior.
The container for inserting contaminated cleaning elements offers the advantage that the cleaning elements, after a single passage through the instrument channel and thus after emerging from the instrument channel, are not required to be detached from the carrier element, but rather can be detached automatically, in particular, from the carrier element by a device in the container interior space and conveyed together with the container toward disposal without any contamination of the environment occurring. Here the container can be produced both as a disposable product with just one cleaning element included and as a reusable product after the insertion of several cleaning elements in a disposal container for collecting several contaminated cleaning elements. As a result of using such a container, the risk of a contamination directly by cleaning personnel from soiled and bacteria-laden cleaning elements is considerably reduced. In addition, according to the invention, it is possible to avoid further contamination of the instrument channel by the withdrawal of the soiled cleaning elements through the instrument channel.
In a particular embodiment, at least one cleaning element is detached from the carrier element of the cleaning device by a device for releasing it in the container at a predetermined cut-off point, which is configured for instance as a preset break point or a tapering of the carrier element.
The device for releasing the cleaning element from the carrier element can comprise various mechanisms for releasing the soiled cleaning elements. In a particular embodiment, at least one cleaning element is released by pinching, together with a part of the carrier element, from the cleaning device. For this particular embodiment, a preset break point can also be provided on the carrier element and can be separated for release by pinching off the cleaning device by the device. Another possibility is to twist or pull off the cleaning element from the carrier element. In this embodiment the carrier element would remain unchanged in its originally geometric form and in its length. All these mechanisms for releasing the soiled cleaning elements from the carrier element in the container interior space have the advantage, however, that the carrier element after it is withdrawn can be provided with new cleaning elements again according to a preparation process and can be used for a new cleaning process and that any recontamination of the instrument channel by impurities and bacteria is considerably reduced.
It has been proven advantageous that the container for inserting contaminated cleaning elements of the cleaning device should comprise a sensor, which determines the position of the cleaning element that is to be released in the container interior space and signals it to the device for detaching and said device automatically releases the designated cleaning element from the carrier element by a release mechanism.
The sensor for detecting the position of the cleaning device in the container interior space has the advantage that the soiled and bacteria-laden cleaning elements are safely and completely released from the carrier element at the cut-off point foreseen for this purpose. This can very securely prevent a soiled cleaning element from being only partly released, or not released at all, from the carrier element and from soiling the carrier element again when it is withdrawn through the instrument channel. In a particular embodiment, the sensor indicates to the user the precise position for releasing the soiled cleaning element from the cleaning device, so that the user inserts the cleaning device sufficiently far into the container interior space for the release process of the cleaning elements from the carrier element. In this manner a secure release of the cleaning elements is guaranteed on the basis of the detected and reported position in the container interior space.
A preferred method for cleaning instrument channels of medical instruments with the cleaning device described above includes the following sequence. After insertion in the instrument channel that is to be cleaned, the cleaning device is moved in axial direction in the instrument channel up to an end point, so that after reaching the end point the cleaning device is moved in the opposite axial direction in the instrument channel. In this context the detachable cleaning element is released from the carrier element and is then no longer part of the cleaning process of the previously cleaned instrument channels.
In this manner, a distribution, in particular of the impurities connected with the releasable cleaning element in the instrument channel, is reduced, because a regularly larger portion of the impurities with the detachable cleaning element is separated from the cleaning device. A cleaning with the present cleaning device is therefore more efficient and reduces the remaining impurities in the instrument channel.
The term “end position” as used so far and hereafter is understood as the reverse point of the motion between the motion of the cleaning device in axial direction and the withdrawal in the opposite axial direction through the instrument channel. The end position of the cleaning device can be selected in such a way that the detachable cleaning element emerges at the end of the instrument channel, and that it is removed manually in an additional working step. Another variant is for the cleaning device, previous to the emergence of the detachable cleaning element from the distal end of the instrument channel, to be withdrawn. In this case the detachable cleaning element after the cleaning process is found in the instrument channel and in an additional step is pushed out of the instrument channel with an additional device. An alternative for this purpose is to use a rod or a carrier element with or without cleaning elements. In a preferred embodiment, the end position of the cleaning device is, however, selected in such a way that the cleaning device is pushed into the instrument channel until the detachable cleaning element emerges completely from the distal end of the instrument channel. Upon emerging from the instrument channel, the cleaning element stretches because of its particularly compressible material properties and falls down upon the withdrawal of the cleaning device from the contact with the instrument channel that is to be cleaned. In this manner the detachable cleaning element is no longer mounted slidably on the carrier element and therefore is no longer part of the cleaning process. The introduction of impurities adhering to the detached cleaning element is thus, according to the invention, prevented.
In a particular embodiment, the cleaning device is pushed forward into the instrument channel until at least one cleaning element emerges completely from the distal end of the instrument channel. After the emergence of the cleaning device from the instrument channel, a part of the carrier element with the soiled cleaning element is separated at a site provided for this purpose. In this manner the cleaning element is no longer part of the cleaning process. The introduction of impurities adhering to the released carrier element with the cleaning element is therefore, according to the invention, prevented.
In a preferred method for cleaning instrument channels, at least one cleaning element that is to be detached when the cleaning device is inserted, after emergence of the cleaning device from the distal end of the instrument channel, in a container for inserting contaminated cleaning elements. In the interior space of the container, through the insertion of the cleaning device, a mechanism is triggered which releases the contaminated and soiled cleaning element from the carrier element and, after removal of the carrier element of the cleaning device from the container, said container is closed in sterile manner.
In summary, the present invention in other words reveals a device and a process for removing impurities from the lumen of medical instruments. It consists of a lengthwise base element and at least one cleaning member that is connected with said base element and is characterized in that at least one cleaning member is separated from the base element during back-and-forth motion of the cleaning device in the lengthwise lumen. The process for cleaning the lumen of medical instruments with the inventive device embraces the following steps:
The apparatus for cleaning the lumen of medical instruments is pushed forward in the longitudinal direction of the lumen as far as a reverse point. After reaching the reverse point, the apparatus for cleaning is moved back in the opposite direction through the lumen of the instrument. Because of the reverse motion of the apparatus to cleaning, the slidable, moveable cleaning member is separated from the base element and is then no longer part of the cleaning process of the previously cleaned instrument lumen and can no longer soil said lumen.
A container receives the contaminated, soiled cleaning members and ensures a secure removal of the soiled cleaning members. The present invention discloses a device and a method for cleaning the lumen of medical instruments that securely transport and dispose of removed substances from the instrument lumen and make possible the requirements for an efficient and good cleaning of the lumen according to the invention.
Additional advantages of the present invention can be seen from the following illustrations of several preferred embodiments. The invention is not restricted to these embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an exemplary inventive cleaning device with a rod-shaped carrier element and with cleaning elements.
FIG. 2 shows a phase of the inventive cleaning process with the inventive cleaning device at the start of the cleaning process.
FIG. 3 shows a phase of the inventive cleaning process with the cleaning device in the end position.
FIG. 4 shows a phase of the inventive cleaning device with the inventive cleaning device after reaching the end point and subsequent withdrawing of the cleaning device.
FIG. 5 shows an exemplary inventive cleaning device with a rod-shaped carrier element and with a fixed cleaning element after the inventive cleaning process.
FIG. 6 shows an exemplary realization of a rod-shaped carrier element for an inventive cleaning device.
FIG. 7 shows an additional variant of the inventive cleaning device with cleaning elements fixed at distances from one another.
FIG. 8 shows a variant of the inventive cleaning device with several cleaning elements of diverse diameter fixed on the carrier element.
FIG. 9 shows a variant of the inventive cleaning device with a particular fixing possibility of the cleaning element.
FIG. 10 shows a variant of the inventive cleaning device with a container for inserting and removing contaminated cleaning elements.
FIG. 11 shows in exemplary fashion an inventive cleaning device with a cleaning element fixed on the carrier element in a device for releasing a cleaning element.
DETAILED DESCRIPTION OF THE INVENTION
The cleaning device illustrated in FIG. 1 shows a carrier element 1 made of a rigid, buckle-resistant, and non-deformable material with cleaning element 2 fixed on the carrier element 1 and with a detachable cleaning element 3 that can slide axially on the carrier element 1 .
The carrier element 1 is made of solid material, such as steel, and has a smaller diameter than the instrument channel 4 that is to be cleaned. The carrier element 1 is longer than the instrumental channel 4 that is to be cleaned, so that the cleaning device can still be held sufficiently well with the hand if the cleaning device is pushed completely through the instrument channel 4 in axial direction to the end position. The cleaning device, depending on the length of the instrument channel 4 that is to be cleaned, has a length of 0.5 m to 3 m and a diameter between 0.1 cm and 0.8 cm.
The cleaning elements 2 and 3 have a greater diameter than the smallest diameter of the instrument channel 4 that is to be cleaned. This prevents the need for specialized personnel in cleaning the instrument channel 4 with the inventive cleaning device to make a back-and-forth motion of the carrier element 1 diagonally to the instrument channel 4 for an efficient cleaning. In this manner, in addition, damage to the entry opening, into which the cleaning device is inserted, is prevented in the instrument channel 4 , because the cleaning device is uniformly passed through the instrument channel 4 .
The cleaning elements 2 and 3 are made of a material with compressible properties, of synthetic material or natural fibers. The structure of the material is felt-like. This has the advantage that cleaning elements 2 and 3 comprise both abrasive and receptive properties. The detachable cleaning element 3 is mounted on the rod-shaped carrier element 1 by a borehole whose diameter is greater than the solid material cross-section of the carrier element 1 . Because the area of the carrier element 1 situated distally from the fixed cleaning element 2 has its surface coated with Teflon, the lubricity of the detachable cleaning element 3 on the carrier element 1 is increased, thereby facilitating the detachment from the carrier element according to the invention.
FIGS. 2 , 3 , and 4 show the preferred method for cleaning with the inventive cleaning device. The cleaning device with a fixed cleaning element 2 in FIG. 2 comprises on the carrier element an axially slidable, detachable cleaning element 3 , which is inserted in an instrument channel 4 that is to be cleaned. The arrangement of one fixed and one detachable cleaning element on a carrier element 1 has the aim that the detachable cleaning element 3 , which lies distally to the fixed cleaning element 2 , should pick up and assemble more impurities, by the sliding of the cleaning device in the instrument channel 4 , than the fixed cleaning element.
FIG. 3 shows the detachment of the cleaning element 2 . This occurs at the end point, which is reached here with the complete emergence of the detachable cleaning element 3 from the instrument channel 4 . For this purpose the rod-shaped carrier element 1 is equipped with a marker 6 , which shows how far the cleaning device is to be inserted by cleaning specialized personnel into the instrument channel 4 .
The cleaning device in FIG. 4 shows no detachable cleaning element 3 . As a result of pulling back the cleaning device through the instrument channel 4 , the detachable cleaning element 3 is released from the carrier element 1 and on emerging from the instrument channel becomes stretched because of its compressible material properties, and is no longer part of the further cleaning process. In this way any distribution, in particular of the impurities connected to the detachable cleaning element 3 in the instrument channel 4 , is reduced. The cleaning is therefore very effective.
FIG. 5 shows the cleaning device after the cleaning of the instrument channel 4 . The detachable cleaning element 3 has detached itself from the carrier element inside the instrument channel because of the reverse motion of the cleaning device. A fixed cleaning element 2 is found on the carrier element. By detaching the cleaning element 3 , the result is a protrusion of the carrier element 1 with a section with a phase 7 distally from the fixed cleaning element 2 , which reduces any spraying of cleaning liquid and the like after removal of the cleaning device from the instrument channel 4 .
A particular embodiment of the attachment feature of a fixed cleaning element 2 is shown in FIG. 6 . The carrier element 1 shows an area that is equipped with a thread 8 . The cleaning element 2 made of felt, which is to be fixed, is screwed onto the thread 8 . For this purpose the cleaning element 2 comprises a borehole whose diameter is slightly larger than the nominal diameter of the carrier element 1 . This makes possible a defined release of the fixed cleaning element 2 from the carrier element 1 .
This offers the advantage that the carrier element 1 can be prepared again by sterilization, for instance, after its use and, equipped with new cleaning elements 2 and 3 that are to be used once, can be applied once more to the cleaning of instrument channels 4 . The re-preparation and reuse of the carrier element 1 allow costs to be clearly reduced. The distal end of the carrier element 1 is rounded in order to avoid damage to the instrument channel 4 and to facilitate simpler insertion of the cleaning device in the instrument channel 4 .
Another particular arrangement of the fixed cleaning elements 2 on the rod-shaped carrier element 1 in accordance with the invention is shown in FIG. 7 . There is an intermediate space between the two fixed cleaning elements 2 . Thanks to this, impurities that are to be expelled are collected in said space and after passing through the instrument channel 4 , on the emergence of the cleaning device out of the instrument channel 4 , they can fall away or be manually removed. In this way the impurities collected in the intermediate space 9 are prevented from being redistributed in the instrument channel 4 upon withdrawal of the cleaning device through said channel. These intermediate spaces 9 also facilitate the insertion of the cleaning device, because the cleaning elements 2 and 3 are made of a compressible material and comprise a greater diameter than the instrument channel 4 . The intermediate space 9 therefore, according to the invention, offers room in which the cleaning elements 2 and 3 spread out because of their shape change upon entering the instrument channel 4 and in this manner they can adapt well to the channel shape. Several cleaning elements 2 , made of felt, are fixed on the carrier element 1 . Therefore they have both abrasive and absorbent properties. The proximally situated fixed cleaning element 10 is made of an elastic synthetic material and in addition is equipped with a blade edge 10 . This has the advantage that liquids that are not completely registered or picked up by the cleaning elements 2 and 3 are skimmed out of the instrument channel 4 .
In the illustrations already described, the diameters of the cleaning elements 2 and 3 on a carrier element 1 are of equal size. FIG. 7 shows an alternative exemplary embodiment of the cleaning device. The cleaning device in FIG. 7 shows several cleaning elements 2 and a detachable cleaning element 3 with various diameters. The diameters are in decreasing size going in the distal direction. This makes possible, first, a simpler insertion of the cleaning device in the instrument channel 4 and, second, because of the varying compression of the cleaning elements 2 and 3 there are diverse degrees of hardness of the cleaning elements 2 and 3 , which support the removal, assembling, and absorbing functions of the cleaning device, leading to an especially effective cleaning.
An alternative configuration for fixing the cleaning element 3 onto the carrier element and for releasing after emergence from the instrument channel 4 is shown in FIG. 9 . The cleaning element 3 is restricted in its slidability on the carrier element 1 by a stop 12 situated proximally and distally on the carrier element 1 . These stops 12 in this embodiment are made of synthetic materials, which are mounted firmly against slipping proximally and distally from the cleaning element 3 . The cleaning element 3 after its distal emergence from the instrument channel 4 is separated by a cutting device at the predetermined cut-off point 11 .
This modular structure of the cleaning device offers the user various possibilities for assembling for individual use in cleaning medical instrument channels.
FIG. 10 shows an inventive cleaning device. The carrier element 1 with cleaning elements 3 , which has passed the distal end of the instrument channel 4 , is inserted into the container interior space of the container 13 for receiving contaminated cleaning elements 3 .
The container 13 is made of polyethylene, in particular, which guarantees a high degree of rigidity of the container. The cleaning device is inserted with the instrument channel 4 of the endoscopic system into the opening 16 of the container. The opening 16 of the container is equipped with a flap, which can be flipped open by the insertion of the cleaning device. If no removal of cleaning elements takes place, the flap on the opening 16 ensures that the container 13 is closed to bacteria and any contamination of the cleaning personnel is avoided. In the container interior space there is a removable refuse container 17 , provided in order to make possible the collection of cleaning elements 3 of several cleaning devices after the detachment from the carrier element 1 .
A sensor 14 in the container 13 informs the user of the correct position of the cleaning device in the device for release 15 by means of the sensor signal, so that the separation is performed by pinching off the carrier element 1 in the device 15 , which leads to the break-up of the foreseen cut-off point 11 and the cleaning element 3 is released from the carrier element 1 and falls into the refuse container 17 of the container for receiving contaminated cleaning elements 13 . As a result, cleaning elements 3 of various cleaning devices can be removed together with the refuse container 17 .
FIG. 11 shows another variant for removing contaminated cleaning elements 3 . The device for detaching 15 here is manually inserted by means of a contaminated cleaning element 3 , which on the distal side extends out of the endoscopic system. By pressing together the device for release 15 , the cleaning element 3 is gripped and exchanged upon drawing back the carrier element 1 . After the ensuing removal of the endoscopic system from the device 15 , the device 15 closes bacteria-free. The device for release 15 together with the collected contaminated cleaning elements 3 is removed as one unit. After release of the contaminated cleaning elements 3 and removal from the instrument channel, the carrier element 1 is prepared again and can be reused. | A device for cleaning channels including a rod-shaped carrier element, at least one cleaning element that is connected with the carrier element, and at least one additional cleaning element that can be detached from the carrier element. A method for cleaning instrument channels wherein the cleaning device is moved in the axial direction in the instrument channel as far as an end point; after reaching the end point the cleaning device is moved back in the opposite axial direction in the instrument channel. Owing to the reverse motion of the cleaning device, the detachable cleaning element is released from the carrier element and thereafter is no longer part of the cleaning process of the previously cleaned instrument channel and can no longer soil the channel. The device and method removes from the instrument channel the substances that are to be removed and produces an efficient and good cleaning result. | Identify the most important aspect in the document and summarize the concept accordingly. | [
"CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority of German patent applications Nos. 10 2008 064 205.3 filed on Dec. 22, 2008 and 10 2009 011 204.9 filed on Mar. 4, 2009.",
"All prior applications are herein incorporated by reference in their entirety.",
"FIELD OF THE INVENTION The present invention relates to a method and a device for cleaning soiled instrument channels, in particular for the efficient cleaning of channels in medical instruments.",
"BACKGROUND OF THE INVENTION If a reusable medical instrument is being used with a patient, then it requires cleaning after its application to the patient.",
"Cleaning of instrumental channels of medical products is particularly difficult.",
"German patent application DE 2006 001 076 A1 discloses a cleaning brush composed of a long, flexible carrier element and a digitally attached brush head.",
"A section of the carrier element extends beyond the bridge head on its digital side.",
"Lengthening the rod-shaped carrier element avoids the scattering of liquids by a swinging or springing motion by the carrier element.",
"Thanks to the distribution of impure materials in the instrument channel by the brush, cleaning with this cleaning brush does not yield a satisfactory cleaning result.",
"European patent application EP 1105061 B1 discloses a method and device for cleaning a soiled lumen of an endoscope, by which the impure materials are distributed uniformly inside the instrument channel by pulling and pushing the cleaning device in the instrument channel.",
"Thereafter, this film uniformly distributed in the channel is treated with an enzymatic cleaning liquid.",
"In this case the cleaning device does not serve to remove substances that are to be expelled from the instrument channel, but rather serves for uniform distribution to improve the subsequent treatment with an enzymatic cleaning liquid.",
"The cleaning effect is not sufficient.",
"The design patent DE 20200700793 U1 discloses a cleaning wick for an instrument channel of a medical instrument.",
"It shows a wick that comprises an adhesive flocking in a partial area.",
"The fibers consist of synthetic material or else natural fibers.",
"When using this cleaning device, the total soiling is distributed after a single pass through the instrument channel, upon withdrawing the cleaning device in the instrument channel.",
"It is necessary to perform a subsequent treatment with cleaning fluid or a repeated cleaning after washing the fibers of the cleaning device.",
"It is the object of the invention to disclose a method and a device for cleaning medical instrument channels that produce an efficient, good cleaning result.",
"SUMMARY OF THE INVENTION The present invention fulfills this object by means of the cleaning device with a rod-shaped carrier element and at least one cleaning element connected with the carrier element, where the cleaning element can be detached from the carrier element, and/or a cleaning method including the steps of moving the cleaning device in the axial direction in the instrument channel up to an end point, so that after reaching the end point the cleaning device is moved outward in the opposite axial direction in the instrument channel and a detachable cleaning element is separated from the carrier element and then is no longer part of the cleaning process of the previously cleaned instrument channel.",
"Advantageous adaptations of the invention are given in the subsidiary claims.",
"The cleaning device in accordance with the present invention contains a rod-shaped carrier element with cleaning elements.",
"The cleaning elements show at least one fixed cleaning element and in addition at least one detachable cleaning element that can be slid axially on the carrier element.",
"As a result of this multi-partite structure of the cleaning elements on the rod-shaped carrier element, any distribution of impurities in the instrument channel can be reduced as much as possible.",
"The multiform structure of the cleaning element serves the purpose of releasing a detachable element positioned on a fixed cleaning element—said detachable element picking up or combining the majority of impurities by pushing the cleaning device forward through the instrument channel—after the typically one-time motion in the axial direction of the instrument channel up to an end point.",
"In the subsequent withdrawal of the cleaning device through the instrument channel, this detachable cleaning element is released from the carrier element and is no longer part of the ensuing typical cleaning process.",
"In this manner, any distribution of impurities in the instrument channel, especially those adhering to the detachable cleaning element, is reduced, because a major portion of the impurities are separated from the cleaning device by the detachable cleaning element.",
"Cleaning with the present cleaning device is therefore more efficient and reduces the impurities in the already cleaned instrument channel.",
"Through the releasing of the detachable cleaning element from the carrier element, there is the additional advantage that on removing the cleaning device from the instrument channel, the extending carrier element on which the distally positioned detachable cleaning element is inserted, prevents any uncontrolled spraying of cleaning fluids and the like that may have been used, by its protrusion, during removal of the remaining cleaning device from the instrument channel.",
"In this manner it is possible to reduce any spraying contamination of the surroundings with possibly infectious material.",
"The terms “detachable”",
"and “fixed,” as used in the foregoing and hereafter, indicate various detaching and fixing possibilities between the cleaning element and the carrier element.",
"In this respect, the term “detachable”",
"is understood to mean a type of connection that allows a sliding of the cleaning element on the carrier element and thus a separation from the carrier element, for instance by slipping or pushing down the cleaning element from the carrier element.",
"Alternatively, the cleaning element, with a part of the carrier element, can also be separated from the rest of the carrier element at a foreseen cut-off point, for instance by means of breaking at a predetermined fracture point or by severing it at a defined cut-off point.",
"The term “fixed”",
"designates a connection that does not allow any sliding of the cleaning element on the carrier element because of the axial motion of the instrument channel.",
"The connection between the cleaning element and the carrier element is preserved during the cleaning process.",
"In a particular embodiment, at least one cleaning element is connected with the carrier element and is configured so that it can be separated from the carrier element.",
"A renewed distribution of the impurities, in particular, that are connected to the detachable cleaning element is reduced in the instrument channel because a great portion of the impurities was separated from the cleaning device through the separation of the cleaning element from the cleaning device.",
"A cleaning is extremely efficient and reduces the impurities in the already cleaned instrument channel.",
"This configuration offers the additional advantage that the cleaning device itself shows a high cleaning quality because of the separation of the cleaning element from the carrier element.",
"One embodiment of the present invention shows that at least one detachable cleaning element is positioned distally on the carrier element and at least one fixed cleaning element is positioned proximally to said first element.",
"This has the advantage that upon withdrawing the cleaning device, the detachable cleaning element can detach itself from the carrier element and in this manner the impurities already collected on the detachable cleaning element are not distributed in the already cleaned instrument channel.",
"The cleaning of the instrument channel is therefore more efficient and allows a better cleaning result.",
"Preferably, the detachable cleaning element is attached to the carrier element by a lubricious connection.",
"It is possible not to push the detachable cleaning element onto the carrier element, but rather to slide it through the instrument channel with the carrier element and the fixed cleaning element.",
"Preferably, however, it is advisable to equip the detachable cleaning element with a bored aperture, through which the carrier element can be pinned onto the detachable cleaning element in sliding fashion.",
"This allows the detachable cleaning element to be slid uniformly through the channel and prevents any irregular deforming of the cleaning element.",
"It has been demonstrated, in particular, that part of the carrier element can be detached with at least one cleaning element by means of a cut-off point provided on the distal end of the carrier element.",
"This embodiment has the advantage that the soiled cleaning element, after it emerges from the instrument channel, can be detached by the carrier element independently of its shape, its material, and its stretch properties, and in this way the impurities already collected and no longer distributed in the instrument channel.",
"The cleaning of the instrument channels is therefore far more efficient.",
"In a particular embodiment, several fixed cleaning elements are secured on the rod-shaped carrier element such as to allow an intermediate space with respect to one another.",
"These inventive intermediate spaces have the advantage that within these spaces it is also possible to transport larger collections of impurities, which can fall away or can be manually removed after one passage of the cleaning device through the instrument channel with the detachable cleaning element.",
"In addition, they allow a spreading of the cleaning elements into the instrument channel in the axial direction, leading to an improved cleaning result.",
"Preferably the carrier element is provided with a stop, which restricts the slidability of the cleaning element on the carrier element.",
"The stop provided for limiting the slidability of the cleaning element prevents the cleaning element from detaching itself from the carrier element during the cleaning process and remaining stuck in the instrument channel.",
"This manner of fixing a cleaning element on the carrier element has the additional advantage that the user can assemble his cleaning device in modular fashion, for instance by making possible the limiting of the slidability of the cleaning elements with synthetic elements, which he can apply distally from the proximal and/or distal end of the cleaning element.",
"It has been shown that the area of the carrier element on which the cleaning element is fixed has, because of the addition or removal of material, the property of fulfilling the purpose of a fixing of the cleaning elements.",
"For instance, applying a metallic structure to the area of the carrier element can enlarge the diameter of the carrier element at this spot, so that a cleaning element that includes a borehole with the diameter of the rest of the carrier element and is pushed onto the rod-shaped carrier element is fixed.",
"An adhesive connection constitutes another preferred possibility for fixing the cleaning element on the carrier element.",
"In a preferred configuration for fixing a cleaning element on the carrier element, areas for fixing onto the carrier element with a thread are provided and fixed thereto so that the cleaning elements to be fixed can be screwed on.",
"This configuration offers the advantage that the carrier element can be prepared anew after its use and, once provided with new cleaning elements, can be applied again to the cleaning of instrument channels.",
"A carrier element that has been prepared anew can be selected as more worthwhile in its material properties and in its design, because it can be used repeatedly for the cleaning of diverse channels.",
"The combination of the cleaning elements as a disposable article and the carrier element as a reusable article therefore offers a considerably more valuable material configuration and likewise cost reduction.",
"During the cleaning process the material can be put under greater pressure through the use of more valuable materials, leading to a better, more efficient cleaning result.",
"The cleaning elements are preferably constructed of a material with compressible properties.",
"A material with compressible properties, preferably with felt-type properties, allows compression of the cleaning element upon insertion into the instrument channel.",
"In this manner the cleaning element is compressed upon shoving the cleaning device onto the instrument channel.",
"This allows a higher abrasive property of the cleaning elements.",
"As a result, greater impurities for instance, as well as hardened substances adhering to the instrument channel, can be removed better.",
"By using the compressible material, the spraying of cleaning liquid and collected impurities in the instrument channel upon removal of the cleaning device from the instrument channel can be avoided because the cleaning elements stretch more uniformly upon removal because of the compressible material.",
"In an especially preferred embodiment, at least one cleaning element can take up and exude a liquid.",
"As a result of the combination of the cleaning device with a liquid, in particular water or a liquid with cleansing properties such as by using enzymatic substances, the cleaning process can be clearly optimized.",
"Preferably not all cleaning elements are provided with a liquid, so that the other cleaning elements on the carrier element can absorb the liquids from the instrument channel.",
"In an additional embodiment the diameter of the cleaning elements is selected so that it is larger than the smallest and largest diameter of the instrument channel that is to be cleaned.",
"If the cleaning elements were to have a smaller diameter than the smallest and largest diameter of the instrument channel, then upon sliding the cleaning device through the instrument channel in the axial direction, the cleaning elements would not continually touch and clean the channel interior.",
"A larger diameter of the cleaning elements than the smallest and largest diameter of the instrument channels, which can also vary in its diameter, therefore prevents a back-and-forth motion of the carrier element diagonally to the instrument channel during the cleaning process by specialized personnel, because the material of the cleaning elements all around the entire channel wall is pressed together.",
"In this manner in particular it is possible to prevent damage, especially by the carrier element in the instrument channel, because the cleaning device is moved uniformly through the instrument channel and an efficient cleaning result is achieved.",
"It has been shown in particular that the outer form of the cross-section of the cleaning elements corresponds to the cross-section of the instrument channel that is to be cleaned.",
"This has the advantage that by means of the same configuration a uniform compression of the material of the cleaning elements, as well as an easier insertion and sliding of the cleaning device through the instrument channel, can be realized.",
"As a result of this arrangement, a lower use of force needs to be applied in moving the cleaning device back and forth in the instrument channel, which clearly reduces the risk of damage inside the instrument channel by erroneous operation and makes the cleaning process more comfortable for the specialized personnel.",
"In addition, owing to this configuration, depending on the choice of the proportion of the dimensions of the cross-section of the instrument channel and cleaning elements to one another, the abrasive property of the cleaning device can be modulated and the cleaning needs can be taken into account.",
"In a particular embodiment of the cleaning device, the degree of hardness of the cleaning elements varies along the rod-shaped carrier element.",
"Owing to this diverse degree of hardness, the cleaning device can be used both for combining and removing larger impurities as well as for absorbing existing liquids that are found increasingly in the instrument channel after the use of a medical instrument on the patient.",
"In this process the cleaning elements with the lower degree of hardness absorb the liquids and impurities present in the instrument channel, while the cleaning elements whose materials show a higher degree of hardness because of their higher abrasive properties, remove and combine together larger and more adherent substances from the instrument channel.",
"According to a particularly preferred embodiment, the hardness properties of the cleaning elements decrease in the direction from proximal to distal on the carrier element.",
"In this particular configuration of the arrangement of the cleaning elements with various hardness properties, there is the advantage that the cleaning device, along with the absorption of liquids and the collection of impurities, can be more easily inserted into the instrument channel.",
"The arrangement of the cleaning elements of diverse hardness properties on the carrier element can, however, also be increasing in the reverse direction.",
"In one embodiment, at least one cleaning element on the carrier element has a hardness gradient of compressible material that varies in the direction from proximal to distal.",
"This gradient leads to a particularly good cleaning result, even if the carrier element is equipped only with few cleaning elements.",
"Thus, for instance, only with a cleaning element that is very long in the axial direction can the impurities in the instrument channel be efficiently combined together.",
"Preferably the cleaning elements on the carrier element are of diverse materials.",
"The design of the cleaning elements on a carrier element with diverse materials allows the adaptation of the cleaning device to the diverse requirements that frequently arise in practice.",
"Thus, for instance, a device can be selected for the cleaning of an irrigation channel that has cleaning elements which consist of an elastic synthetic material whose sides are provided with a blade edge.",
"The combination of cleaning elements with felt-type properties with cleaning elements of synthetic material, for instance a spongy material, is also very effective especially when using cleaning liquids.",
"In a particular embodiment, the cleaning elements on a carrier element have different diameters.",
"In a special configuration of this model, the diameters of the cleaning elements are positioned in declining order from the proximal to the distal side.",
"As a result the insertion of the cleaning device into the instrument channel and thus the handling is simplified, but because of the decreasing diameters of the cleaning elements from proximal to distal side, the cleaning elements decreasing from proximal to distal side are compressed to varying degrees, so that because of this configuration the strongly compressed cleaning elements show a stronger combining or abrasive function and the less compressed cleaning elements show instead an increasing function.",
"The arrangement of the diverse diameters of the cleaning elements can also vary, however, or else can be selected as decreasing from the distal to the proximal side.",
"It has proven especially beneficial to optimize the slidability of the distally situated cleaning elements on the carrier element by coating the area of the carrier element that is situated distally to the fixed cleaning element preferably with an especially lubricious surface, for instance with Teflon, or by making it from a corresponding low-friction material.",
"The rigid rod-shaped carrier element can also be coated with a low-friction synthetic material, such as polytetrafluorethylene (PTFE), or with another lubricious material such as Teflon.",
"Such a low-friction realization of the surface of the rod-shaped carrier element facilitates the removal of the detachable cleaning element from the carrier element after a single passage through the instrument channel and in addition, upon contact of the carrier element with the instrument channel that is to be cleaned, prevents damage to the channel of the instrument.",
"It has been shown that it is advantageous to choose for the carrier element a rigid material, in particular steel.",
"The term “rigid,” as used here, is understood to mean a material that has a high buckling resistance, stability, and cannot be deformed.",
"This makes possible a very reliable and safe cleaning, especially for straight, rigid endoscopes.",
"Depending on the size of the cross-section, the material can also have elastic properties or can be made of an elastic material so that the cleaning device is well adapted to the shape of the instrument channel and also can be used for cleaning flexible and possibly bent medical instruments.",
"An additional possibility is to segment the rod-shaped carrier element to reach various areas with elastic and deformable properties and to be able to clean especially efficient, difficult channel geometries.",
"In a preferred embodiment, the carrier element is made of a solid material.",
"If the rod-shaped carrier element consists of solid material, then despite small cross-section surfaces, which are often used in cleaning channels of small instruments with small diameters, it can have very high stability and resistance to buckling.",
"In particular, the solid material also offers the advantage that no impurities can collect in the carrier element that, in turn, need to be cleaned with a cleaning device if the carrier element takes the form of a reprocessed product.",
"It has been shown in particular that the carrier element comprises a phase at its ends.",
"A phase at the ends of the carrier element has the advantage that damage that can be caused by the cleaning device in the instrument channel, for instance by grazing along the channel surface, can be avoided and in addition that introduction of the cleaning device into the instrument channel is supported.",
"Preferably a marker is provided on the carrier element constituting a measurement for the insertion depth of the cleaning device in the instrument channel and representing the desired end position of the cleaning device in the instrument channel.",
"This has the advantage that all parts of the instrument channel are reliably cleaned and the marker enables the user to clean the instrument channel completely without moving the device unnecessarily far outside the channel in the distal direction.",
"Thus the detachable cleaning element, corresponding to the position of the marker, for instance, can be pushed out of the instrument channel only so far that part of the cleaning element remains inside the instrument channel and is fixed in such a way that it can, however, be manually removed from the channel.",
"The detachable cleaning element, in this manner, does not fall uncontrollably out of the instrument channel, and an uncontrolled distribution of collected substances into the environment by the detachable cleaning element is avoided.",
"Alternatively, the position of the marker can also be selected in such a way that the detachable cleaning element extends entirely out of the channel in the distal direction and becomes detached when pulled back.",
"The handling of the cleaning device is therefore further improved by this marker.",
"It has been shown to be advantageous to provide for the cleaning device a container for inserting contaminated cleaning elements with a closeable opening.",
"Through this opening it is possible for at least one cleaning element of the cleaning device to be brought into container interior space.",
"In addition, according to the invention, the container is provided with a device for detaching at least one cleaning element from a carrier element in the container interior.",
"The container for inserting contaminated cleaning elements offers the advantage that the cleaning elements, after a single passage through the instrument channel and thus after emerging from the instrument channel, are not required to be detached from the carrier element, but rather can be detached automatically, in particular, from the carrier element by a device in the container interior space and conveyed together with the container toward disposal without any contamination of the environment occurring.",
"Here the container can be produced both as a disposable product with just one cleaning element included and as a reusable product after the insertion of several cleaning elements in a disposal container for collecting several contaminated cleaning elements.",
"As a result of using such a container, the risk of a contamination directly by cleaning personnel from soiled and bacteria-laden cleaning elements is considerably reduced.",
"In addition, according to the invention, it is possible to avoid further contamination of the instrument channel by the withdrawal of the soiled cleaning elements through the instrument channel.",
"In a particular embodiment, at least one cleaning element is detached from the carrier element of the cleaning device by a device for releasing it in the container at a predetermined cut-off point, which is configured for instance as a preset break point or a tapering of the carrier element.",
"The device for releasing the cleaning element from the carrier element can comprise various mechanisms for releasing the soiled cleaning elements.",
"In a particular embodiment, at least one cleaning element is released by pinching, together with a part of the carrier element, from the cleaning device.",
"For this particular embodiment, a preset break point can also be provided on the carrier element and can be separated for release by pinching off the cleaning device by the device.",
"Another possibility is to twist or pull off the cleaning element from the carrier element.",
"In this embodiment the carrier element would remain unchanged in its originally geometric form and in its length.",
"All these mechanisms for releasing the soiled cleaning elements from the carrier element in the container interior space have the advantage, however, that the carrier element after it is withdrawn can be provided with new cleaning elements again according to a preparation process and can be used for a new cleaning process and that any recontamination of the instrument channel by impurities and bacteria is considerably reduced.",
"It has been proven advantageous that the container for inserting contaminated cleaning elements of the cleaning device should comprise a sensor, which determines the position of the cleaning element that is to be released in the container interior space and signals it to the device for detaching and said device automatically releases the designated cleaning element from the carrier element by a release mechanism.",
"The sensor for detecting the position of the cleaning device in the container interior space has the advantage that the soiled and bacteria-laden cleaning elements are safely and completely released from the carrier element at the cut-off point foreseen for this purpose.",
"This can very securely prevent a soiled cleaning element from being only partly released, or not released at all, from the carrier element and from soiling the carrier element again when it is withdrawn through the instrument channel.",
"In a particular embodiment, the sensor indicates to the user the precise position for releasing the soiled cleaning element from the cleaning device, so that the user inserts the cleaning device sufficiently far into the container interior space for the release process of the cleaning elements from the carrier element.",
"In this manner a secure release of the cleaning elements is guaranteed on the basis of the detected and reported position in the container interior space.",
"A preferred method for cleaning instrument channels of medical instruments with the cleaning device described above includes the following sequence.",
"After insertion in the instrument channel that is to be cleaned, the cleaning device is moved in axial direction in the instrument channel up to an end point, so that after reaching the end point the cleaning device is moved in the opposite axial direction in the instrument channel.",
"In this context the detachable cleaning element is released from the carrier element and is then no longer part of the cleaning process of the previously cleaned instrument channels.",
"In this manner, a distribution, in particular of the impurities connected with the releasable cleaning element in the instrument channel, is reduced, because a regularly larger portion of the impurities with the detachable cleaning element is separated from the cleaning device.",
"A cleaning with the present cleaning device is therefore more efficient and reduces the remaining impurities in the instrument channel.",
"The term “end position”",
"as used so far and hereafter is understood as the reverse point of the motion between the motion of the cleaning device in axial direction and the withdrawal in the opposite axial direction through the instrument channel.",
"The end position of the cleaning device can be selected in such a way that the detachable cleaning element emerges at the end of the instrument channel, and that it is removed manually in an additional working step.",
"Another variant is for the cleaning device, previous to the emergence of the detachable cleaning element from the distal end of the instrument channel, to be withdrawn.",
"In this case the detachable cleaning element after the cleaning process is found in the instrument channel and in an additional step is pushed out of the instrument channel with an additional device.",
"An alternative for this purpose is to use a rod or a carrier element with or without cleaning elements.",
"In a preferred embodiment, the end position of the cleaning device is, however, selected in such a way that the cleaning device is pushed into the instrument channel until the detachable cleaning element emerges completely from the distal end of the instrument channel.",
"Upon emerging from the instrument channel, the cleaning element stretches because of its particularly compressible material properties and falls down upon the withdrawal of the cleaning device from the contact with the instrument channel that is to be cleaned.",
"In this manner the detachable cleaning element is no longer mounted slidably on the carrier element and therefore is no longer part of the cleaning process.",
"The introduction of impurities adhering to the detached cleaning element is thus, according to the invention, prevented.",
"In a particular embodiment, the cleaning device is pushed forward into the instrument channel until at least one cleaning element emerges completely from the distal end of the instrument channel.",
"After the emergence of the cleaning device from the instrument channel, a part of the carrier element with the soiled cleaning element is separated at a site provided for this purpose.",
"In this manner the cleaning element is no longer part of the cleaning process.",
"The introduction of impurities adhering to the released carrier element with the cleaning element is therefore, according to the invention, prevented.",
"In a preferred method for cleaning instrument channels, at least one cleaning element that is to be detached when the cleaning device is inserted, after emergence of the cleaning device from the distal end of the instrument channel, in a container for inserting contaminated cleaning elements.",
"In the interior space of the container, through the insertion of the cleaning device, a mechanism is triggered which releases the contaminated and soiled cleaning element from the carrier element and, after removal of the carrier element of the cleaning device from the container, said container is closed in sterile manner.",
"In summary, the present invention in other words reveals a device and a process for removing impurities from the lumen of medical instruments.",
"It consists of a lengthwise base element and at least one cleaning member that is connected with said base element and is characterized in that at least one cleaning member is separated from the base element during back-and-forth motion of the cleaning device in the lengthwise lumen.",
"The process for cleaning the lumen of medical instruments with the inventive device embraces the following steps: The apparatus for cleaning the lumen of medical instruments is pushed forward in the longitudinal direction of the lumen as far as a reverse point.",
"After reaching the reverse point, the apparatus for cleaning is moved back in the opposite direction through the lumen of the instrument.",
"Because of the reverse motion of the apparatus to cleaning, the slidable, moveable cleaning member is separated from the base element and is then no longer part of the cleaning process of the previously cleaned instrument lumen and can no longer soil said lumen.",
"A container receives the contaminated, soiled cleaning members and ensures a secure removal of the soiled cleaning members.",
"The present invention discloses a device and a method for cleaning the lumen of medical instruments that securely transport and dispose of removed substances from the instrument lumen and make possible the requirements for an efficient and good cleaning of the lumen according to the invention.",
"Additional advantages of the present invention can be seen from the following illustrations of several preferred embodiments.",
"The invention is not restricted to these embodiments.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an exemplary inventive cleaning device with a rod-shaped carrier element and with cleaning elements.",
"FIG. 2 shows a phase of the inventive cleaning process with the inventive cleaning device at the start of the cleaning process.",
"FIG. 3 shows a phase of the inventive cleaning process with the cleaning device in the end position.",
"FIG. 4 shows a phase of the inventive cleaning device with the inventive cleaning device after reaching the end point and subsequent withdrawing of the cleaning device.",
"FIG. 5 shows an exemplary inventive cleaning device with a rod-shaped carrier element and with a fixed cleaning element after the inventive cleaning process.",
"FIG. 6 shows an exemplary realization of a rod-shaped carrier element for an inventive cleaning device.",
"FIG. 7 shows an additional variant of the inventive cleaning device with cleaning elements fixed at distances from one another.",
"FIG. 8 shows a variant of the inventive cleaning device with several cleaning elements of diverse diameter fixed on the carrier element.",
"FIG. 9 shows a variant of the inventive cleaning device with a particular fixing possibility of the cleaning element.",
"FIG. 10 shows a variant of the inventive cleaning device with a container for inserting and removing contaminated cleaning elements.",
"FIG. 11 shows in exemplary fashion an inventive cleaning device with a cleaning element fixed on the carrier element in a device for releasing a cleaning element.",
"DETAILED DESCRIPTION OF THE INVENTION The cleaning device illustrated in FIG. 1 shows a carrier element 1 made of a rigid, buckle-resistant, and non-deformable material with cleaning element 2 fixed on the carrier element 1 and with a detachable cleaning element 3 that can slide axially on the carrier element 1 .",
"The carrier element 1 is made of solid material, such as steel, and has a smaller diameter than the instrument channel 4 that is to be cleaned.",
"The carrier element 1 is longer than the instrumental channel 4 that is to be cleaned, so that the cleaning device can still be held sufficiently well with the hand if the cleaning device is pushed completely through the instrument channel 4 in axial direction to the end position.",
"The cleaning device, depending on the length of the instrument channel 4 that is to be cleaned, has a length of 0.5 m to 3 m and a diameter between 0.1 cm and 0.8 cm.",
"The cleaning elements 2 and 3 have a greater diameter than the smallest diameter of the instrument channel 4 that is to be cleaned.",
"This prevents the need for specialized personnel in cleaning the instrument channel 4 with the inventive cleaning device to make a back-and-forth motion of the carrier element 1 diagonally to the instrument channel 4 for an efficient cleaning.",
"In this manner, in addition, damage to the entry opening, into which the cleaning device is inserted, is prevented in the instrument channel 4 , because the cleaning device is uniformly passed through the instrument channel 4 .",
"The cleaning elements 2 and 3 are made of a material with compressible properties, of synthetic material or natural fibers.",
"The structure of the material is felt-like.",
"This has the advantage that cleaning elements 2 and 3 comprise both abrasive and receptive properties.",
"The detachable cleaning element 3 is mounted on the rod-shaped carrier element 1 by a borehole whose diameter is greater than the solid material cross-section of the carrier element 1 .",
"Because the area of the carrier element 1 situated distally from the fixed cleaning element 2 has its surface coated with Teflon, the lubricity of the detachable cleaning element 3 on the carrier element 1 is increased, thereby facilitating the detachment from the carrier element according to the invention.",
"FIGS. 2 , 3 , and 4 show the preferred method for cleaning with the inventive cleaning device.",
"The cleaning device with a fixed cleaning element 2 in FIG. 2 comprises on the carrier element an axially slidable, detachable cleaning element 3 , which is inserted in an instrument channel 4 that is to be cleaned.",
"The arrangement of one fixed and one detachable cleaning element on a carrier element 1 has the aim that the detachable cleaning element 3 , which lies distally to the fixed cleaning element 2 , should pick up and assemble more impurities, by the sliding of the cleaning device in the instrument channel 4 , than the fixed cleaning element.",
"FIG. 3 shows the detachment of the cleaning element 2 .",
"This occurs at the end point, which is reached here with the complete emergence of the detachable cleaning element 3 from the instrument channel 4 .",
"For this purpose the rod-shaped carrier element 1 is equipped with a marker 6 , which shows how far the cleaning device is to be inserted by cleaning specialized personnel into the instrument channel 4 .",
"The cleaning device in FIG. 4 shows no detachable cleaning element 3 .",
"As a result of pulling back the cleaning device through the instrument channel 4 , the detachable cleaning element 3 is released from the carrier element 1 and on emerging from the instrument channel becomes stretched because of its compressible material properties, and is no longer part of the further cleaning process.",
"In this way any distribution, in particular of the impurities connected to the detachable cleaning element 3 in the instrument channel 4 , is reduced.",
"The cleaning is therefore very effective.",
"FIG. 5 shows the cleaning device after the cleaning of the instrument channel 4 .",
"The detachable cleaning element 3 has detached itself from the carrier element inside the instrument channel because of the reverse motion of the cleaning device.",
"A fixed cleaning element 2 is found on the carrier element.",
"By detaching the cleaning element 3 , the result is a protrusion of the carrier element 1 with a section with a phase 7 distally from the fixed cleaning element 2 , which reduces any spraying of cleaning liquid and the like after removal of the cleaning device from the instrument channel 4 .",
"A particular embodiment of the attachment feature of a fixed cleaning element 2 is shown in FIG. 6 .",
"The carrier element 1 shows an area that is equipped with a thread 8 .",
"The cleaning element 2 made of felt, which is to be fixed, is screwed onto the thread 8 .",
"For this purpose the cleaning element 2 comprises a borehole whose diameter is slightly larger than the nominal diameter of the carrier element 1 .",
"This makes possible a defined release of the fixed cleaning element 2 from the carrier element 1 .",
"This offers the advantage that the carrier element 1 can be prepared again by sterilization, for instance, after its use and, equipped with new cleaning elements 2 and 3 that are to be used once, can be applied once more to the cleaning of instrument channels 4 .",
"The re-preparation and reuse of the carrier element 1 allow costs to be clearly reduced.",
"The distal end of the carrier element 1 is rounded in order to avoid damage to the instrument channel 4 and to facilitate simpler insertion of the cleaning device in the instrument channel 4 .",
"Another particular arrangement of the fixed cleaning elements 2 on the rod-shaped carrier element 1 in accordance with the invention is shown in FIG. 7 .",
"There is an intermediate space between the two fixed cleaning elements 2 .",
"Thanks to this, impurities that are to be expelled are collected in said space and after passing through the instrument channel 4 , on the emergence of the cleaning device out of the instrument channel 4 , they can fall away or be manually removed.",
"In this way the impurities collected in the intermediate space 9 are prevented from being redistributed in the instrument channel 4 upon withdrawal of the cleaning device through said channel.",
"These intermediate spaces 9 also facilitate the insertion of the cleaning device, because the cleaning elements 2 and 3 are made of a compressible material and comprise a greater diameter than the instrument channel 4 .",
"The intermediate space 9 therefore, according to the invention, offers room in which the cleaning elements 2 and 3 spread out because of their shape change upon entering the instrument channel 4 and in this manner they can adapt well to the channel shape.",
"Several cleaning elements 2 , made of felt, are fixed on the carrier element 1 .",
"Therefore they have both abrasive and absorbent properties.",
"The proximally situated fixed cleaning element 10 is made of an elastic synthetic material and in addition is equipped with a blade edge 10 .",
"This has the advantage that liquids that are not completely registered or picked up by the cleaning elements 2 and 3 are skimmed out of the instrument channel 4 .",
"In the illustrations already described, the diameters of the cleaning elements 2 and 3 on a carrier element 1 are of equal size.",
"FIG. 7 shows an alternative exemplary embodiment of the cleaning device.",
"The cleaning device in FIG. 7 shows several cleaning elements 2 and a detachable cleaning element 3 with various diameters.",
"The diameters are in decreasing size going in the distal direction.",
"This makes possible, first, a simpler insertion of the cleaning device in the instrument channel 4 and, second, because of the varying compression of the cleaning elements 2 and 3 there are diverse degrees of hardness of the cleaning elements 2 and 3 , which support the removal, assembling, and absorbing functions of the cleaning device, leading to an especially effective cleaning.",
"An alternative configuration for fixing the cleaning element 3 onto the carrier element and for releasing after emergence from the instrument channel 4 is shown in FIG. 9 .",
"The cleaning element 3 is restricted in its slidability on the carrier element 1 by a stop 12 situated proximally and distally on the carrier element 1 .",
"These stops 12 in this embodiment are made of synthetic materials, which are mounted firmly against slipping proximally and distally from the cleaning element 3 .",
"The cleaning element 3 after its distal emergence from the instrument channel 4 is separated by a cutting device at the predetermined cut-off point 11 .",
"This modular structure of the cleaning device offers the user various possibilities for assembling for individual use in cleaning medical instrument channels.",
"FIG. 10 shows an inventive cleaning device.",
"The carrier element 1 with cleaning elements 3 , which has passed the distal end of the instrument channel 4 , is inserted into the container interior space of the container 13 for receiving contaminated cleaning elements 3 .",
"The container 13 is made of polyethylene, in particular, which guarantees a high degree of rigidity of the container.",
"The cleaning device is inserted with the instrument channel 4 of the endoscopic system into the opening 16 of the container.",
"The opening 16 of the container is equipped with a flap, which can be flipped open by the insertion of the cleaning device.",
"If no removal of cleaning elements takes place, the flap on the opening 16 ensures that the container 13 is closed to bacteria and any contamination of the cleaning personnel is avoided.",
"In the container interior space there is a removable refuse container 17 , provided in order to make possible the collection of cleaning elements 3 of several cleaning devices after the detachment from the carrier element 1 .",
"A sensor 14 in the container 13 informs the user of the correct position of the cleaning device in the device for release 15 by means of the sensor signal, so that the separation is performed by pinching off the carrier element 1 in the device 15 , which leads to the break-up of the foreseen cut-off point 11 and the cleaning element 3 is released from the carrier element 1 and falls into the refuse container 17 of the container for receiving contaminated cleaning elements 13 .",
"As a result, cleaning elements 3 of various cleaning devices can be removed together with the refuse container 17 .",
"FIG. 11 shows another variant for removing contaminated cleaning elements 3 .",
"The device for detaching 15 here is manually inserted by means of a contaminated cleaning element 3 , which on the distal side extends out of the endoscopic system.",
"By pressing together the device for release 15 , the cleaning element 3 is gripped and exchanged upon drawing back the carrier element 1 .",
"After the ensuing removal of the endoscopic system from the device 15 , the device 15 closes bacteria-free.",
"The device for release 15 together with the collected contaminated cleaning elements 3 is removed as one unit.",
"After release of the contaminated cleaning elements 3 and removal from the instrument channel, the carrier element 1 is prepared again and can be reused."
] |
FIELD OF THE INVENTION
[0001] The present invention relates to network communications and, in particular, to streaming data in a peer-to-peer network.
BACKGROUND OF THE INVENTION
[0002] The prior art shows that the maximum video streaming rate in a peer-to-peer (P2P) streaming system is determined by the video source server's capacity, the number of the peers in the system, and the aggregate uploading capacity of all peers. A centralized “perfect” scheduling algorithm was described in order to achieve the maximum streaming rate. However, the “perfect” scheduling algorithm has two shortcomings. First, it requires a central scheduler that collects the upload capacity information of all of the individual peers. The central scheduler then computes the rate of sub-streams sent from the source to the peers. In the “perfect” scheduling algorithm, the central scheduler is a single point/unit/device. As used herein, “/” denotes alternative names for the same or similar components or structures. That is, a “/” can be taken as meaning “or” as used herein. Moreover, peer upload capacity information may not be available and varies over time. Inaccurate upload capacity leads to incorrect sub-stream rates that would either under utilize the system bandwidth or over-estimate the supportable streaming rate.
[0003] A fully connected mesh between the server and all peers is required. In a P2P system that routinely has thousands of peers, it is unrealistic for a peer to maintain thousands of active P2P connections. In addition, the server needs to split the video stream into sub-streams, one for each peer. It will be challenging for a server to partition a video stream into thousands of sub-streams in real-time.
[0004] In an earlier application, PCT/US07/025,656, a hierarchically clustered P2P live streaming system was designed that divides the peers into small clusters and forms a hierarchy among the clusters. The hierarchically clustered P2P system achieves the streaming rate close to the theoretical upper bound. A peer need only maintain connections with a small number of neighboring peers within the cluster. The centralized “perfect” scheduling method is employed within the individual clusters.
[0005] In another earlier patent application PCT/US07/15246 a decentralized version of the “perfect” scheduling with peers forming a fully connected mesh was described.
SUMMARY OF THE INVENTION
[0006] The present invention is directed towards a fully distributed scheduling mechanism for a hierarchically clustered P2P live streaming system. The distributed scheduling mechanism is executed at the source server and peer nodes. It utilizes local information and no central controller is required at the cluster level. Decentralized hierarchically clustered P2P live streaming system thus overcomes two major shortcomings of the original “perfect” scheduling algorithm.
[0007] The hierarchically clustered P2P streaming method of the present invention is described in terms of live video streaming. However, any form of data can be streamed including but not limited to video, audio, multimedia, streaming content, files, etc.
[0008] A method and apparatus are described including forwarding data in a transmission queue to a first peer in a same cluster, computing an average transmission queue size, comparing the average transmission queue size to a threshold, sending a signal to a cluster head based on a result of the comparison. A method and apparatus are also described including forwarding data in a transmission queue to a peer associated with an upper level peer, forwarding data in a playback buffer to a peer in a lower level cluster responsive to a first signal in a signal queue associated with the lower level cluster, determining if the playback buffer has exceeded a threshold for a period of time, sending a second signal to a source server based on a result of the determination. A method and apparatus are further described including forwarding data responsive to a signal in a signal queue to an issuer of the signal and forwarding data in a content buffer to a peer in a same cluster. Further described are a method and apparatus including determining if a source server can serve more data, moving the more data to a content buffer if the source server can serve more data, determining if a first sub-server is lagging significantly behind a second sub-server, executing the first sub-server's data handling process if the first sub-server is lagging significantly behind the second sub-server and executing the second sub-server's data handling process if the first sub-server is not lagging significantly behind the second sub-server.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention is best understood from the following detailed description when read in conjunction with the accompanying drawings. The drawings include the following figures briefly described below where like-numbers on the figures represent similar elements:
[0010] FIG. 1 is a schematic diagram of a prior art P2P system using the “perfect” scheduling algorithm.
[0011] FIG. 2 is a schematic diagram of the Hierarchical Clustered P2P Streaming (HCPS) system of the prior art.
[0012] FIG. 3 shows the queueing model for a “normal” peer/node of the present invention.
[0013] FIG. 4 shows the queueing model for a cluster head of the present invention.
[0014] FIG. 5 shows the queueing model for the source server of the present invention.
[0015] FIG. 6 shows the architecture of a “normal” peer/node of the present invention.
[0016] FIG. 7 is a flowchart of the data handling process of a “normal” peer/node of the present invention.
[0017] FIG. 8 shows the architecture of a cluster head of the present invention.
[0018] FIG. 9 is a flowchart of the data handling process of a cluster head of the present invention.
[0019] FIG. 10 shows the architecture of the source server of the present invention.
[0020] FIG. 11A is a flowchart of the data handling process of a sub-server of the present invention.
[0021] FIG. 11B is a flowchart of the data handling process of the source server of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] A prior art scheme described a “perfect” scheduling algorithm that achieves the maximum streaming rate allowed by a P2P system. There are n peers in the system, and peer i's upload capacity is u i , i=1, 2, . . . , n. There is one source (the server) in the system with an upload capacity of u s . Denote by r max the maximum streaming rate allowed by the system, which can be expressed as:
[0000]
r
max
=
min
{
u
s
,
u
s
+
∑
i
=
1
n
u
i
n
}
(
1
)
[0000] The value of
[0000]
(
u
s
+
∑
i
=
1
n
u
i
)
/
n
[0000] is the average upload capacity per peer.
[0023] FIG. 1 shows an example how the different portions of data are scheduled among three heterogeneous nodes using the “perfect” scheduling algorithm of the prior art. There are three peers/nodes in the system. The source server has a capacity of 6 chunks per time-unit, where chunk is the basic data unit. The upload capacities of a, b and c are 2 chunks per time-unit, 4 chunks/time-unit and 6 chunks/time-unit, respectively. Suppose the peers all have enough downloading capacity, the maximum data/video rate can be supported by the system is 6 chunks/time-unit. To achieve that rate, the server divides the data/video chunks into groups of 6. Node a is responsible for uploading 1 chunk out of each group while nodes b and c are responsible for upload 2 and 3 chunks within each group. This way, all peers can download data/video at the maximum rate of 6 chunks/units. To implement such a “perfect” scheduling algorithm, each peer needs to maintain a connection and exchange data/video content with all other peers in the system. Additionally, the server needs to split the video stream into multiple sub-streams with different rates, one for each peer. A real practical P2P streaming system can easily have a few thousand of peers. With current operating systems, it is unrealistic for a regular peer to maintain thousands of concurrent connections. It is also challenging for a server to partition a data/video stream into thousands of sub-streams in real time.
[0024] The hierarchically Clustered P2P Streaming (HCPS) system of the previous invention supports a streaming rate approaching the optimum upper bound with short delay, yet is scalable to accommodate a large number of users/peers/nodes/clients in practice. In the HCPS of the previous invention, the peers are grouped into small size clusters and a hierarchy is formed among clusters to retrieve data/video from the source server. By actively balancing the uploading capacities among the clusters, and executing the “perfect” scheduling algorithm within each cluster, the system resources can be efficiently utilized.
[0025] FIG. 2 depicts a two-level HCPS system. Peers/nodes are organized into bandwidth-balanced clusters, where each cluster consists of a small number of peers. In the current example, 30 peers are evenly divided into six clusters. Within each cluster, one peer is selected as the cluster head. Cluster head acts as the local data/video proxy server for the peers in its cluster. “Normal” peers maintain connections within the cluster but do not have to maintain connections with peers/nodes in other clusters. Cluster heads not only maintain connections with peers of the cluster they heads, they also participate as peers in an upper-level cluster from which data/video is retrieved. For instance, in FIG. 2 , cluster heads of all clusters form two upper-level clusters to retrieve data/video from the data/video source server. In the architecture of the present invention, the source server distributes data/video to the cluster heads and peers in the upper level cluster. The exemplary two-level HCPS has the ability to support a large number of peers with minimal connection requirements on the server, cluster heads and normal peers.
[0026] While the peers within the same cluster could collaborate according to the “perfect” scheduling algorithm to retrieve data/video from their cluster head, the “perfect” scheduling employed in HCPS does not work well in practice. Described herein is a decentralized scheduling mechanism that works for the HCPS architecture of the present invention. The decentralized scheduling method of the present invention is able to serve a large number of users/peers/nodes, while individual users/peers/nodes maintain a small number of peer/node connections and exchange data with other peers/nodes/users according to locally available information.
[0027] There are three types of nodes/peers in the HCPS system of the present invention: source server, cluster head, and “normal” peer. The source server is the true server of the entire system. The source server serves one or multiple top-level clusters. For instance, the source server in FIG. 2 serves two top-level clusters. A cluster head participates in two clusters: upper-level cluster and lower-level cluster. A cluster head behaves as a “normal” peer in the upper level cluster and obtains the data/video content from the upper level cluster. That is, in the upper level cluster the cluster head receives streaming content from the source server/cluster head and/or by exchanging data/streaming content with other cluster heads (nodes/peers) in the cluster. The cluster head serves as the local source for the lower-level cluster. Finally, a “normal” peer is a peer/node that participates in only one cluster. It receives the streaming content from the cluster head and exchanges data with other peers within the same cluster. In FIG. 2 , peers a 1 , a 2 , a 3 , and b 1 , b 2 , b 3 are cluster heads. They act as the source (so behave like source servers) in their respective lower-level clusters. Meanwhile, cluster heads a 1 , a 2 , a 3 , and the source server form one top-level cluster. Cluster heads b 1 , b 2 , b 3 , and the source server form the other top-level cluster. It should be noted that an architecture including more than two-levels is possible and a two-level architecture is used herein in order to explain the principles of the present invention.
[0028] Next the decentralized scheduling mechanism, the queuing model, and the architecture for a “normal” peer (at the lower level), a cluster head, and the source server, are respectively described.
[0029] As shown in FIG. 3 , a “normal” peer/node (lower level) maintains a playback buffer that stores all received streaming content. The “normal” peer/node also maintains a forwarding queue that stores the content to be forwarded to all other “normal” peers/nodes within the cluster. The content obtained from the cluster head acting as the source is marked as either “F” or “NF” content. “F” represents that the content needs to be relayed to other “normal” peers/nodes within the cluster. “NF” means that the content is intended for this peer only and no forwarding is required. The content received from other “normal” peers is always marked as ‘NF’ content. The received content is first saved into the playback buffer. The ‘F’ marked content marked is then stored into the forwarding queue and to be forwarded to other “normal” peers within the cluster. Whenever the forwarding queue becomes empty, the “normal” peer issues a “pull” signal to the cluster head requesting more content.
[0030] FIG. 6 illustrates the architecture of a normal peer. The receiving process handles the incoming traffic from cluster head and other “normal” peers. The received data is then handed over to data handling process. The data handling process includes a “pull” signal issuer, a packet handler and a playback buffer. Data chunks stored in the playback buffer are rendered such that a user (at a peer/node) can view the streamed data stored in the playback buffer as a continuous program. The data and signals that need to be sent to other nodes are stored in the transmission queues. The transmission process handles the transmission of data and signals in the transmission queues. The receiving process, data handling process and transmission process may each be separate processes/modules within a “normal” peer or may be a single process/module. Similarly, the process/module that issues a “pull” signal, the process/module that handles data packets and the playback buffer may be implemented in a single process/module or separate processes/modules. The processes/modules may be implemented in software with the instructions stored in a memory of a processor or may be implemented in hardware or firmware using application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) etc. The queues and buffers described may be implemented in storage, which may be an integral part of a processor or may be separate units/devices. The peer-to-peer connections can be established over wired network, wireless network, or the combination of them.
[0031] FIG. 7 is the flow chart describes the method of the present invention at a “normal” peer/node. At 705 the “normal” peer receives data chunks at the receiving process. The receiving process received the incoming data chunks from the cluster head and/or other “normal” peers/nodes in the cluster. The data chunks are then passed to the data handling process and are stored by the packet handler of data handling process in the playback buffer at 710 . The “F” marked data chunks are also forwarded by the packet handler to the transmission process for storing into the transmission queues. The “F” marked data chunks are un-marked in the transmission queues and forwarded to all peers/nodes within the same cluster at 715 . The “pull” signal issuer calculates the average queue size of the transmission queue at 720 . A test is performed at 725 to determine if the average queue size is less than or equal to a predetermined threshold value. If the average queue size is less than or equal to the predetermined threshold value then the “pull” signal issuer generates a “pull” signal and sends the pull signal to the cluster head in order to obtain more content/data at 730 . If the average queue size is greater than the predetermined threshold value then processing proceeds to 705 .
[0032] Cluster heads joins two clusters. That is, a cluster head will be a member of two clusters concurrently. A cluster head behaves as a “normal” peer in the upper-level cluster and as the source node in the lower-level cluster. The queuing model of the cluster head, thus, is two levels as well, as shown in FIG. 4 . As a “normal” node in the upper-level cluster, the cluster head receives the content from peers within the same cluster as well as from the source server. It relays the ‘F’ marked content to other peers in the same upper level cluster and issues “pull” signals to the source server when it needs more content. At the upper level, the cluster head also may issue a throttle signal to the source server, which is described in more detail below.
[0033] Still referring to FIG. 4 , as the source in the lower-level cluster, the cluster head has two queues: a content queue and a signal queue. The content queue is a multi-server queue with two servers: an “F” marked content server and a forwarding server. Which server to use depends on the status of the signal queue. Specifically, if there is ‘pull’ signal in the signal queue, a small chunk of content is taken off content buffer, marked as “F”, and served by the “F” marked content server to the peer that issued the “pull” signal. The “pull” signal is then removed from the “pull” signal queue. On the other hand, if the signal queue is empty, the server takes a small chunk of content (data chunk) from the content buffer and transfers it to the forwarding server. The forwarding server marks the data chunk as “NF” and sends it to all peers in the same cluster.
[0034] A cluster head's upload capacity is shared between upper-level cluster and lower level cluster. In order to achieve the maximum streaming rate allowed by a dHCPS system, the forwarding server and “F” marked content server in the lower-level cluster always has priority over the forwarding queue in the upper-level cluster. Specifically, the cluster head will not serve the forwarding queuing in the upper-level until the content in the playback buffer for the lower-level cluster has been fully served.
[0035] A lower-level cluster can be overwhelmed by the upper-level cluster if the streaming rate supported at the upper-level cluster is larger than the streaming rate supported by the lower-level cluster. If the entire upload capacity of the cluster head has been used in the lower-level, yet the content accumulated in the upper-level content buffer continues to increase, it can be inferred that the current streaming rate is too large to be supported by the lower-level cluster. A feedback mechanism at the playback buffer of the cluster head is introduced. The playback buffer has a content rate estimator that continuously estimates the incoming streaming rate. A threshold is set at the playback buffer. If the received content is over the threshold for an extended period of time, say t, the cluster head will send a throttle signal together with the estimated incoming streaming rate to the source server. The signal reports to the source server that the current streaming rate surpasses the rate that can be consumed by the lower-level cluster headed by this node. The source server responds to the ‘throttle’ signal and acts correspondingly to reduce the streaming rate. The source server may choose to respond to the “throttle” signal and acts correspondingly to reduce the streaming rate. As an alternative, the source server may choose not to slow down the current streaming rate. In that case, the peer(s) in the cluster that issued the throttle signal will experience degraded viewing quality such as frequent frame freezing. However, the quality degradation does not spill over to other clusters.
[0036] FIG. 8 depicts the architecture of a cluster head. The receiving process handles the incoming traffic from both upper-level cluster and lower-level cluster. The received data is then handed over to data handling process. The data handling process for the upper level includes a packet handler, playback buffer and “pull” signal issuer. Data chunks stored in the playback buffer are rendered such that a user (at a cluster head) can view the streamed data stored in the playback buffer as a continuous program. The data handling process for the lower level includes a packet handler, a “pull” signal handler and a throttle signal issuer. The incoming queues for low-level cluster only receive ‘pull’ signals. The data and signals that need to be sent to other nodes are stored in the transmission queues. The transmission process handles the transmission of data in the transmission queues. The data chunks in the upper level cluster queues are transmitted to other cluster heads/peers in the upper-level cluster, and the data chunks in the lower level transmission queues are transmitted to the peers in the lower level cluster for which this cluster head is the source. The transmission process gives higher priority to the traffic in the lower-level cluster.
[0037] The receiving process, data handling process and transmission process may each be separate processes/modules within a cluster head or may be a single process/module. Similarly, the process/module that issues a “pull” signal, the process/module that handles packets and the playback buffer may be implemented in a single process/module or separate processes/modules. The processes/modules may be implemented in software with the instructions stored in a memory of a processor or may be implemented in hardware or firmware using application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) etc. The queues and buffers described may be implemented in storage, which may be an integral part of a processor or may be separate units/devices.
[0038] FIG. 9 is the flow chart describes the process of data handling for a cluster head. At 905 the cluster head receives incoming data chunks (upper level incoming queues) and stores the received incoming data chunks in its playback buffer. The packet handler of the upper level data handling process stores the data chunks marked “F” into the transmission queues in the upper level cluster of the transmission process at 910 . The “F” marked data chunks are to be forwarded to other cluster heads and peers in the same cluster. The packet handler of the lower level data handling process inspects the signal queue and if there is a “pull” signal pending at 915 , the packet handler of the lower level data handling process removes the pending “pull” signal from the “pull” signal queue and serves K “F′ marked data chunks to the “normal” peer in the lower level cluster that issued the “pull” signal at 920 . Receiving a “pull” signal from a lower level cluster indicates that the lower level cluster's queue is empty or that the average queue size is below a predetermined threshold. The process then loops back to 915 . If the “pull” signal queue is empty then the next data chunk in the playback buffer is marked as “NF” and served to all peers in the same lower level cluster at 925 . A test is performed at 930 to determine if the playback buffer has been over a threshold for an extended predetermined period of time, t. If the playback buffer has been over a threshold for an extended predetermined period of time, t, then a throttle signal is generated and sent to the source server at 935 . If the playback buffer has not been over a threshold for an extended predetermined period of time, t, then processing proceeds to 905 .
[0039] Referring to FIG. 5 , the source server in HCPS system may participate in one or multiple top-level clusters. The source server has one sub-server for each top-level cluster. Each sub-server includes two queues: content queue and signal queue. The content queue is a multi-server queue with two servers: ‘F’ marked content server and forwarding server. Which server to use depends on the status of the signal queue. Specifically, if there is ‘pull’ signal in the signal queue, a small chunk of content is taken off content buffer, marked as “F”, and served by the ‘F’ marked content server to the peer that issued the ‘pull’ signal. The ‘pull’ signal is thereby consumed (and removed from the signal queue). On the other hand, if the signal queue is empty, the server takes a small chunk of content off the content buffer and hands it to the forwarding server. The forwarding server marks the chunk as ‘NF’ and sends it to all peers in the cluster.
[0040] The source server maintains an original content queue that stores the data/streaming content. It also handles the ‘throttle’ signals from the lower level clusters and from cluster heads the source server serves at the top-level clusters. The server regulates the streaming rate according to the ‘throttle’ signals from the peers/nodes. The server's upload capacity is shared among all top-level clusters. The bandwidth sharing follows the following rules:
[0041] The cluster that lags behind other clusters significantly (by a threshold in terms of content queue size) has the highest priority to use the upload capacity.
[0042] If all content queues are of the same/similar size, then clusters/sub-servers are served in a round robin fashion.
[0043] FIG. 10 depicts the architecture of the source server. The receiving process handles the incoming ‘pull’ signals from the members of the top-level clusters. The source server has a throttle signal handler. The data/video source is pushed into sub-servers' content buffers. A throttle signal may hold back such data pushing process, and change the streaming rate to the rate suggested by the throttle signal. The data handling process for each sub-server includes a packet handler and a “pull” signal handler. Upon serving a ‘pull’ signal, data chunks in the sub-server's content buffer are pushed into the transmission queue for the peer that issues the ‘pull’ signal. If the “pull” signal queue is empty, a data chunk is pushed into the transmission queues to all peers in the cluster. The transmission process handles the transmission of data in the transmission queues in a round robin fashion. The receiving process, data handling process and transmission process may each be separate processes/modules within the source server or may be a single process/module. Similarly, the process/module that issues a “pull” signal, the process/module that handles packets and the playback buffer may be implemented in a single process/module or separate processes/modules. The processes/modules may be implemented in software with the instructions stored in a memory of a processor or may be implemented in hardware or firmware using application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) etc. The queues and buffers described may be implemented in storage, which may be an integral part of a processor or may be separate units/devices.
[0044] FIG. 11A is the flow chart describes the data handling process of the sub-server. In this exemplary implementation, the sub-server data handling process inspects the signal queue and if there is a “pull” signal pending at 1105 , the packet handler removes the pending “pull” signal from the “pull” signal queue and serves K “F” marked data chunks to the peer that issued the “pull” signal at 1110 . The process then loops back to 1105 . If the “pull” signal queue is empty then the next data chunk in the playback buffer is marked as “NF” and served to all peers in the same cluster at 1115 .
[0045] FIG. 11B is the flow chart describes the data handling process of the source server. A test is performed at 1120 to determine if the source server can send/serve more data to the peers headed by the source server. More data are pushed into sub-servers' content buffers if allowed at 1123 . At 1125 , the sub-server that lags significantly is identified according to the bandwidth sharing rule described above. The identified sub-server gets to run its data handling process first at 1130 and thus put more data chunks into transmission queue. Since transmission process will treat all transmission queues fairly, the sub-server that stores more data chunks into transmission queues get to use more bandwidth. The process then loops back to 1125 . If no sub-server significantly lags behind, the process proceeds to 1135 and the cluster counter is initialized. The cluster counter is initialized to zero. The cluster counter may be initialized to one, in which case the test at 1150 would be against n+1. In yet another alternative embodiment the cluster counter may be initialized to the highest numbered cluster first and decremented. Counter initialization and incrementation or decrementation is well known in the art. The data handling process of the corresponding sub-server is executed at 1140 . The cluster counter is incremented at 1145 and a test is performed at 1150 to determine if the last cluster head has been served in this round of service. If the last cluster head has been served in this round of service, then processing looks back to 1120 .
[0046] The invention describe herein can achieve the maximum/optimal streaming rate allowed by the P2P system with the specific peer-to-peer overlay topology. If a constant-bit-rate (CBR) video is streamed over such a P2P system, all peers/users can be supported as long as the constant bit rate is smaller than the maximum supportable streaming rate.
[0047] The invention described herein does not assume any knowledge of the underlying network topology or the support of a dedicated network infrastructure such as in-network cache proxies or CDN (content distribution network) edge servers. If such information or infrastructure support is available, the decentralized HCPS (dHCPS) of the present invention is able to take advantage of such and deliver better user quality of experience (QoE). For instance, if the network topology is known, dHCPS can group the close-by peers into the same cluster hence reduce the traffic load on the underlying network and shorten the propagation delays. As another example, if in-network cache proxies or CDN edge servers are available to support the live streaming, dHCPS can use them as cluster heads since this dedicated network infrastructure typically has more upload capacity and are less likely to leave the network suddenly.
[0048] It is to be understood that the present invention may be implemented in various forms of hardware (e.g. ASIC chip), software, firmware, special purpose processors, or a combination thereof, for example, within a server, an intermediate device (such as a wireless access point, a wireless router, a set-top box, or mobile device). Preferably, the present invention is implemented as a combination of hardware and software. Moreover, the software is preferably implemented as an application program tangibly embodied on a program storage device. The application program may be uploaded to, and executed by, a machine comprising any suitable architecture. Preferably, the machine is implemented on a computer platform having hardware such as one or more central processing units (CPU), a random access memory (RAM), and input/output (I/O) interface(s). The computer platform also includes an operating system and microinstruction code. The various processes and functions described herein may either be part of the microinstruction code or part of the application program (or a combination thereof), which is executed via the operating system. In addition, various other peripheral devices may be connected to the computer platform such as an additional data storage device and a printing device.
[0049] It is to be further understood that, because some of the constituent system components and method steps depicted in the accompanying figures are preferably implemented in software, the actual connections between the system components (or the process steps) may differ depending upon the manner in which the present invention is programmed. Given the teachings herein, one of ordinary skill in the related art will be able to contemplate these and similar implementations or configurations of the present invention. | A method and apparatus are described including forwarding data in a transmission queue to a first peer in a same cluster, computing an average transmission queue size to a threshold, sending a signal to a cluster head based on a result of the comparison. A method and apparatus are also described including forwarding data in a transmission queue to a peer associated with an upper level peer, forwarding data in a playback buffer to a peer in a lower level cluster responsive to a first signal in a signal queue associated with the lower level cluster, determining if the playback buffer has exceeded a threshold for a period of time, sending a second signal to a source server based on a result of the determination. | Briefly summarize the invention's components and working principles as described in the document. | [
"FIELD OF THE INVENTION [0001] The present invention relates to network communications and, in particular, to streaming data in a peer-to-peer network.",
"BACKGROUND OF THE INVENTION [0002] The prior art shows that the maximum video streaming rate in a peer-to-peer (P2P) streaming system is determined by the video source server's capacity, the number of the peers in the system, and the aggregate uploading capacity of all peers.",
"A centralized “perfect”",
"scheduling algorithm was described in order to achieve the maximum streaming rate.",
"However, the “perfect”",
"scheduling algorithm has two shortcomings.",
"First, it requires a central scheduler that collects the upload capacity information of all of the individual peers.",
"The central scheduler then computes the rate of sub-streams sent from the source to the peers.",
"In the “perfect”",
"scheduling algorithm, the central scheduler is a single point/unit/device.",
"As used herein, “/”",
"denotes alternative names for the same or similar components or structures.",
"That is, a “/”",
"can be taken as meaning “or”",
"as used herein.",
"Moreover, peer upload capacity information may not be available and varies over time.",
"Inaccurate upload capacity leads to incorrect sub-stream rates that would either under utilize the system bandwidth or over-estimate the supportable streaming rate.",
"[0003] A fully connected mesh between the server and all peers is required.",
"In a P2P system that routinely has thousands of peers, it is unrealistic for a peer to maintain thousands of active P2P connections.",
"In addition, the server needs to split the video stream into sub-streams, one for each peer.",
"It will be challenging for a server to partition a video stream into thousands of sub-streams in real-time.",
"[0004] In an earlier application, PCT/US07/025,656, a hierarchically clustered P2P live streaming system was designed that divides the peers into small clusters and forms a hierarchy among the clusters.",
"The hierarchically clustered P2P system achieves the streaming rate close to the theoretical upper bound.",
"A peer need only maintain connections with a small number of neighboring peers within the cluster.",
"The centralized “perfect”",
"scheduling method is employed within the individual clusters.",
"[0005] In another earlier patent application PCT/US07/15246 a decentralized version of the “perfect”",
"scheduling with peers forming a fully connected mesh was described.",
"SUMMARY OF THE INVENTION [0006] The present invention is directed towards a fully distributed scheduling mechanism for a hierarchically clustered P2P live streaming system.",
"The distributed scheduling mechanism is executed at the source server and peer nodes.",
"It utilizes local information and no central controller is required at the cluster level.",
"Decentralized hierarchically clustered P2P live streaming system thus overcomes two major shortcomings of the original “perfect”",
"scheduling algorithm.",
"[0007] The hierarchically clustered P2P streaming method of the present invention is described in terms of live video streaming.",
"However, any form of data can be streamed including but not limited to video, audio, multimedia, streaming content, files, etc.",
"[0008] A method and apparatus are described including forwarding data in a transmission queue to a first peer in a same cluster, computing an average transmission queue size, comparing the average transmission queue size to a threshold, sending a signal to a cluster head based on a result of the comparison.",
"A method and apparatus are also described including forwarding data in a transmission queue to a peer associated with an upper level peer, forwarding data in a playback buffer to a peer in a lower level cluster responsive to a first signal in a signal queue associated with the lower level cluster, determining if the playback buffer has exceeded a threshold for a period of time, sending a second signal to a source server based on a result of the determination.",
"A method and apparatus are further described including forwarding data responsive to a signal in a signal queue to an issuer of the signal and forwarding data in a content buffer to a peer in a same cluster.",
"Further described are a method and apparatus including determining if a source server can serve more data, moving the more data to a content buffer if the source server can serve more data, determining if a first sub-server is lagging significantly behind a second sub-server, executing the first sub-server's data handling process if the first sub-server is lagging significantly behind the second sub-server and executing the second sub-server's data handling process if the first sub-server is not lagging significantly behind the second sub-server.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0009] The present invention is best understood from the following detailed description when read in conjunction with the accompanying drawings.",
"The drawings include the following figures briefly described below where like-numbers on the figures represent similar elements: [0010] FIG. 1 is a schematic diagram of a prior art P2P system using the “perfect”",
"scheduling algorithm.",
"[0011] FIG. 2 is a schematic diagram of the Hierarchical Clustered P2P Streaming (HCPS) system of the prior art.",
"[0012] FIG. 3 shows the queueing model for a “normal”",
"peer/node of the present invention.",
"[0013] FIG. 4 shows the queueing model for a cluster head of the present invention.",
"[0014] FIG. 5 shows the queueing model for the source server of the present invention.",
"[0015] FIG. 6 shows the architecture of a “normal”",
"peer/node of the present invention.",
"[0016] FIG. 7 is a flowchart of the data handling process of a “normal”",
"peer/node of the present invention.",
"[0017] FIG. 8 shows the architecture of a cluster head of the present invention.",
"[0018] FIG. 9 is a flowchart of the data handling process of a cluster head of the present invention.",
"[0019] FIG. 10 shows the architecture of the source server of the present invention.",
"[0020] FIG. 11A is a flowchart of the data handling process of a sub-server of the present invention.",
"[0021] FIG. 11B is a flowchart of the data handling process of the source server of the present invention.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0022] A prior art scheme described a “perfect”",
"scheduling algorithm that achieves the maximum streaming rate allowed by a P2P system.",
"There are n peers in the system, and peer i's upload capacity is u i , i=1, 2, .",
", n. There is one source (the server) in the system with an upload capacity of u s .",
"Denote by r max the maximum streaming rate allowed by the system, which can be expressed as: [0000] r max = min { u s , u s + ∑ i = 1 n u i n } ( 1 ) [0000] The value of [0000] ( u s + ∑ i = 1 n u i ) / n [0000] is the average upload capacity per peer.",
"[0023] FIG. 1 shows an example how the different portions of data are scheduled among three heterogeneous nodes using the “perfect”",
"scheduling algorithm of the prior art.",
"There are three peers/nodes in the system.",
"The source server has a capacity of 6 chunks per time-unit, where chunk is the basic data unit.",
"The upload capacities of a, b and c are 2 chunks per time-unit, 4 chunks/time-unit and 6 chunks/time-unit, respectively.",
"Suppose the peers all have enough downloading capacity, the maximum data/video rate can be supported by the system is 6 chunks/time-unit.",
"To achieve that rate, the server divides the data/video chunks into groups of 6.",
"Node a is responsible for uploading 1 chunk out of each group while nodes b and c are responsible for upload 2 and 3 chunks within each group.",
"This way, all peers can download data/video at the maximum rate of 6 chunks/units.",
"To implement such a “perfect”",
"scheduling algorithm, each peer needs to maintain a connection and exchange data/video content with all other peers in the system.",
"Additionally, the server needs to split the video stream into multiple sub-streams with different rates, one for each peer.",
"A real practical P2P streaming system can easily have a few thousand of peers.",
"With current operating systems, it is unrealistic for a regular peer to maintain thousands of concurrent connections.",
"It is also challenging for a server to partition a data/video stream into thousands of sub-streams in real time.",
"[0024] The hierarchically Clustered P2P Streaming (HCPS) system of the previous invention supports a streaming rate approaching the optimum upper bound with short delay, yet is scalable to accommodate a large number of users/peers/nodes/clients in practice.",
"In the HCPS of the previous invention, the peers are grouped into small size clusters and a hierarchy is formed among clusters to retrieve data/video from the source server.",
"By actively balancing the uploading capacities among the clusters, and executing the “perfect”",
"scheduling algorithm within each cluster, the system resources can be efficiently utilized.",
"[0025] FIG. 2 depicts a two-level HCPS system.",
"Peers/nodes are organized into bandwidth-balanced clusters, where each cluster consists of a small number of peers.",
"In the current example, 30 peers are evenly divided into six clusters.",
"Within each cluster, one peer is selected as the cluster head.",
"Cluster head acts as the local data/video proxy server for the peers in its cluster.",
"“Normal”",
"peers maintain connections within the cluster but do not have to maintain connections with peers/nodes in other clusters.",
"Cluster heads not only maintain connections with peers of the cluster they heads, they also participate as peers in an upper-level cluster from which data/video is retrieved.",
"For instance, in FIG. 2 , cluster heads of all clusters form two upper-level clusters to retrieve data/video from the data/video source server.",
"In the architecture of the present invention, the source server distributes data/video to the cluster heads and peers in the upper level cluster.",
"The exemplary two-level HCPS has the ability to support a large number of peers with minimal connection requirements on the server, cluster heads and normal peers.",
"[0026] While the peers within the same cluster could collaborate according to the “perfect”",
"scheduling algorithm to retrieve data/video from their cluster head, the “perfect”",
"scheduling employed in HCPS does not work well in practice.",
"Described herein is a decentralized scheduling mechanism that works for the HCPS architecture of the present invention.",
"The decentralized scheduling method of the present invention is able to serve a large number of users/peers/nodes, while individual users/peers/nodes maintain a small number of peer/node connections and exchange data with other peers/nodes/users according to locally available information.",
"[0027] There are three types of nodes/peers in the HCPS system of the present invention: source server, cluster head, and “normal”",
"peer.",
"The source server is the true server of the entire system.",
"The source server serves one or multiple top-level clusters.",
"For instance, the source server in FIG. 2 serves two top-level clusters.",
"A cluster head participates in two clusters: upper-level cluster and lower-level cluster.",
"A cluster head behaves as a “normal”",
"peer in the upper level cluster and obtains the data/video content from the upper level cluster.",
"That is, in the upper level cluster the cluster head receives streaming content from the source server/cluster head and/or by exchanging data/streaming content with other cluster heads (nodes/peers) in the cluster.",
"The cluster head serves as the local source for the lower-level cluster.",
"Finally, a “normal”",
"peer is a peer/node that participates in only one cluster.",
"It receives the streaming content from the cluster head and exchanges data with other peers within the same cluster.",
"In FIG. 2 , peers a 1 , a 2 , a 3 , and b 1 , b 2 , b 3 are cluster heads.",
"They act as the source (so behave like source servers) in their respective lower-level clusters.",
"Meanwhile, cluster heads a 1 , a 2 , a 3 , and the source server form one top-level cluster.",
"Cluster heads b 1 , b 2 , b 3 , and the source server form the other top-level cluster.",
"It should be noted that an architecture including more than two-levels is possible and a two-level architecture is used herein in order to explain the principles of the present invention.",
"[0028] Next the decentralized scheduling mechanism, the queuing model, and the architecture for a “normal”",
"peer (at the lower level), a cluster head, and the source server, are respectively described.",
"[0029] As shown in FIG. 3 , a “normal”",
"peer/node (lower level) maintains a playback buffer that stores all received streaming content.",
"The “normal”",
"peer/node also maintains a forwarding queue that stores the content to be forwarded to all other “normal”",
"peers/nodes within the cluster.",
"The content obtained from the cluster head acting as the source is marked as either “F”",
"or “NF”",
"content.",
"“F”",
"represents that the content needs to be relayed to other “normal”",
"peers/nodes within the cluster.",
"“NF”",
"means that the content is intended for this peer only and no forwarding is required.",
"The content received from other “normal”",
"peers is always marked as ‘NF’ content.",
"The received content is first saved into the playback buffer.",
"The ‘F’ marked content marked is then stored into the forwarding queue and to be forwarded to other “normal”",
"peers within the cluster.",
"Whenever the forwarding queue becomes empty, the “normal”",
"peer issues a “pull”",
"signal to the cluster head requesting more content.",
"[0030] FIG. 6 illustrates the architecture of a normal peer.",
"The receiving process handles the incoming traffic from cluster head and other “normal”",
"peers.",
"The received data is then handed over to data handling process.",
"The data handling process includes a “pull”",
"signal issuer, a packet handler and a playback buffer.",
"Data chunks stored in the playback buffer are rendered such that a user (at a peer/node) can view the streamed data stored in the playback buffer as a continuous program.",
"The data and signals that need to be sent to other nodes are stored in the transmission queues.",
"The transmission process handles the transmission of data and signals in the transmission queues.",
"The receiving process, data handling process and transmission process may each be separate processes/modules within a “normal”",
"peer or may be a single process/module.",
"Similarly, the process/module that issues a “pull”",
"signal, the process/module that handles data packets and the playback buffer may be implemented in a single process/module or separate processes/modules.",
"The processes/modules may be implemented in software with the instructions stored in a memory of a processor or may be implemented in hardware or firmware using application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) etc.",
"The queues and buffers described may be implemented in storage, which may be an integral part of a processor or may be separate units/devices.",
"The peer-to-peer connections can be established over wired network, wireless network, or the combination of them.",
"[0031] FIG. 7 is the flow chart describes the method of the present invention at a “normal”",
"peer/node.",
"At 705 the “normal”",
"peer receives data chunks at the receiving process.",
"The receiving process received the incoming data chunks from the cluster head and/or other “normal”",
"peers/nodes in the cluster.",
"The data chunks are then passed to the data handling process and are stored by the packet handler of data handling process in the playback buffer at 710 .",
"The “F”",
"marked data chunks are also forwarded by the packet handler to the transmission process for storing into the transmission queues.",
"The “F”",
"marked data chunks are un-marked in the transmission queues and forwarded to all peers/nodes within the same cluster at 715 .",
"The “pull”",
"signal issuer calculates the average queue size of the transmission queue at 720 .",
"A test is performed at 725 to determine if the average queue size is less than or equal to a predetermined threshold value.",
"If the average queue size is less than or equal to the predetermined threshold value then the “pull”",
"signal issuer generates a “pull”",
"signal and sends the pull signal to the cluster head in order to obtain more content/data at 730 .",
"If the average queue size is greater than the predetermined threshold value then processing proceeds to 705 .",
"[0032] Cluster heads joins two clusters.",
"That is, a cluster head will be a member of two clusters concurrently.",
"A cluster head behaves as a “normal”",
"peer in the upper-level cluster and as the source node in the lower-level cluster.",
"The queuing model of the cluster head, thus, is two levels as well, as shown in FIG. 4 .",
"As a “normal”",
"node in the upper-level cluster, the cluster head receives the content from peers within the same cluster as well as from the source server.",
"It relays the ‘F’ marked content to other peers in the same upper level cluster and issues “pull”",
"signals to the source server when it needs more content.",
"At the upper level, the cluster head also may issue a throttle signal to the source server, which is described in more detail below.",
"[0033] Still referring to FIG. 4 , as the source in the lower-level cluster, the cluster head has two queues: a content queue and a signal queue.",
"The content queue is a multi-server queue with two servers: an “F”",
"marked content server and a forwarding server.",
"Which server to use depends on the status of the signal queue.",
"Specifically, if there is ‘pull’ signal in the signal queue, a small chunk of content is taken off content buffer, marked as “F”, and served by the “F”",
"marked content server to the peer that issued the “pull”",
"signal.",
"The “pull”",
"signal is then removed from the “pull”",
"signal queue.",
"On the other hand, if the signal queue is empty, the server takes a small chunk of content (data chunk) from the content buffer and transfers it to the forwarding server.",
"The forwarding server marks the data chunk as “NF”",
"and sends it to all peers in the same cluster.",
"[0034] A cluster head's upload capacity is shared between upper-level cluster and lower level cluster.",
"In order to achieve the maximum streaming rate allowed by a dHCPS system, the forwarding server and “F”",
"marked content server in the lower-level cluster always has priority over the forwarding queue in the upper-level cluster.",
"Specifically, the cluster head will not serve the forwarding queuing in the upper-level until the content in the playback buffer for the lower-level cluster has been fully served.",
"[0035] A lower-level cluster can be overwhelmed by the upper-level cluster if the streaming rate supported at the upper-level cluster is larger than the streaming rate supported by the lower-level cluster.",
"If the entire upload capacity of the cluster head has been used in the lower-level, yet the content accumulated in the upper-level content buffer continues to increase, it can be inferred that the current streaming rate is too large to be supported by the lower-level cluster.",
"A feedback mechanism at the playback buffer of the cluster head is introduced.",
"The playback buffer has a content rate estimator that continuously estimates the incoming streaming rate.",
"A threshold is set at the playback buffer.",
"If the received content is over the threshold for an extended period of time, say t, the cluster head will send a throttle signal together with the estimated incoming streaming rate to the source server.",
"The signal reports to the source server that the current streaming rate surpasses the rate that can be consumed by the lower-level cluster headed by this node.",
"The source server responds to the ‘throttle’ signal and acts correspondingly to reduce the streaming rate.",
"The source server may choose to respond to the “throttle”",
"signal and acts correspondingly to reduce the streaming rate.",
"As an alternative, the source server may choose not to slow down the current streaming rate.",
"In that case, the peer(s) in the cluster that issued the throttle signal will experience degraded viewing quality such as frequent frame freezing.",
"However, the quality degradation does not spill over to other clusters.",
"[0036] FIG. 8 depicts the architecture of a cluster head.",
"The receiving process handles the incoming traffic from both upper-level cluster and lower-level cluster.",
"The received data is then handed over to data handling process.",
"The data handling process for the upper level includes a packet handler, playback buffer and “pull”",
"signal issuer.",
"Data chunks stored in the playback buffer are rendered such that a user (at a cluster head) can view the streamed data stored in the playback buffer as a continuous program.",
"The data handling process for the lower level includes a packet handler, a “pull”",
"signal handler and a throttle signal issuer.",
"The incoming queues for low-level cluster only receive ‘pull’ signals.",
"The data and signals that need to be sent to other nodes are stored in the transmission queues.",
"The transmission process handles the transmission of data in the transmission queues.",
"The data chunks in the upper level cluster queues are transmitted to other cluster heads/peers in the upper-level cluster, and the data chunks in the lower level transmission queues are transmitted to the peers in the lower level cluster for which this cluster head is the source.",
"The transmission process gives higher priority to the traffic in the lower-level cluster.",
"[0037] The receiving process, data handling process and transmission process may each be separate processes/modules within a cluster head or may be a single process/module.",
"Similarly, the process/module that issues a “pull”",
"signal, the process/module that handles packets and the playback buffer may be implemented in a single process/module or separate processes/modules.",
"The processes/modules may be implemented in software with the instructions stored in a memory of a processor or may be implemented in hardware or firmware using application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) etc.",
"The queues and buffers described may be implemented in storage, which may be an integral part of a processor or may be separate units/devices.",
"[0038] FIG. 9 is the flow chart describes the process of data handling for a cluster head.",
"At 905 the cluster head receives incoming data chunks (upper level incoming queues) and stores the received incoming data chunks in its playback buffer.",
"The packet handler of the upper level data handling process stores the data chunks marked “F”",
"into the transmission queues in the upper level cluster of the transmission process at 910 .",
"The “F”",
"marked data chunks are to be forwarded to other cluster heads and peers in the same cluster.",
"The packet handler of the lower level data handling process inspects the signal queue and if there is a “pull”",
"signal pending at 915 , the packet handler of the lower level data handling process removes the pending “pull”",
"signal from the “pull”",
"signal queue and serves K “F′ marked data chunks to the “normal”",
"peer in the lower level cluster that issued the “pull”",
"signal at 920 .",
"Receiving a “pull”",
"signal from a lower level cluster indicates that the lower level cluster's queue is empty or that the average queue size is below a predetermined threshold.",
"The process then loops back to 915 .",
"If the “pull”",
"signal queue is empty then the next data chunk in the playback buffer is marked as “NF”",
"and served to all peers in the same lower level cluster at 925 .",
"A test is performed at 930 to determine if the playback buffer has been over a threshold for an extended predetermined period of time, t. If the playback buffer has been over a threshold for an extended predetermined period of time, t, then a throttle signal is generated and sent to the source server at 935 .",
"If the playback buffer has not been over a threshold for an extended predetermined period of time, t, then processing proceeds to 905 .",
"[0039] Referring to FIG. 5 , the source server in HCPS system may participate in one or multiple top-level clusters.",
"The source server has one sub-server for each top-level cluster.",
"Each sub-server includes two queues: content queue and signal queue.",
"The content queue is a multi-server queue with two servers: ‘F’ marked content server and forwarding server.",
"Which server to use depends on the status of the signal queue.",
"Specifically, if there is ‘pull’ signal in the signal queue, a small chunk of content is taken off content buffer, marked as “F”, and served by the ‘F’ marked content server to the peer that issued the ‘pull’ signal.",
"The ‘pull’ signal is thereby consumed (and removed from the signal queue).",
"On the other hand, if the signal queue is empty, the server takes a small chunk of content off the content buffer and hands it to the forwarding server.",
"The forwarding server marks the chunk as ‘NF’ and sends it to all peers in the cluster.",
"[0040] The source server maintains an original content queue that stores the data/streaming content.",
"It also handles the ‘throttle’ signals from the lower level clusters and from cluster heads the source server serves at the top-level clusters.",
"The server regulates the streaming rate according to the ‘throttle’ signals from the peers/nodes.",
"The server's upload capacity is shared among all top-level clusters.",
"The bandwidth sharing follows the following rules: [0041] The cluster that lags behind other clusters significantly (by a threshold in terms of content queue size) has the highest priority to use the upload capacity.",
"[0042] If all content queues are of the same/similar size, then clusters/sub-servers are served in a round robin fashion.",
"[0043] FIG. 10 depicts the architecture of the source server.",
"The receiving process handles the incoming ‘pull’ signals from the members of the top-level clusters.",
"The source server has a throttle signal handler.",
"The data/video source is pushed into sub-servers'",
"content buffers.",
"A throttle signal may hold back such data pushing process, and change the streaming rate to the rate suggested by the throttle signal.",
"The data handling process for each sub-server includes a packet handler and a “pull”",
"signal handler.",
"Upon serving a ‘pull’ signal, data chunks in the sub-server's content buffer are pushed into the transmission queue for the peer that issues the ‘pull’ signal.",
"If the “pull”",
"signal queue is empty, a data chunk is pushed into the transmission queues to all peers in the cluster.",
"The transmission process handles the transmission of data in the transmission queues in a round robin fashion.",
"The receiving process, data handling process and transmission process may each be separate processes/modules within the source server or may be a single process/module.",
"Similarly, the process/module that issues a “pull”",
"signal, the process/module that handles packets and the playback buffer may be implemented in a single process/module or separate processes/modules.",
"The processes/modules may be implemented in software with the instructions stored in a memory of a processor or may be implemented in hardware or firmware using application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) etc.",
"The queues and buffers described may be implemented in storage, which may be an integral part of a processor or may be separate units/devices.",
"[0044] FIG. 11A is the flow chart describes the data handling process of the sub-server.",
"In this exemplary implementation, the sub-server data handling process inspects the signal queue and if there is a “pull”",
"signal pending at 1105 , the packet handler removes the pending “pull”",
"signal from the “pull”",
"signal queue and serves K “F”",
"marked data chunks to the peer that issued the “pull”",
"signal at 1110 .",
"The process then loops back to 1105 .",
"If the “pull”",
"signal queue is empty then the next data chunk in the playback buffer is marked as “NF”",
"and served to all peers in the same cluster at 1115 .",
"[0045] FIG. 11B is the flow chart describes the data handling process of the source server.",
"A test is performed at 1120 to determine if the source server can send/serve more data to the peers headed by the source server.",
"More data are pushed into sub-servers'",
"content buffers if allowed at 1123 .",
"At 1125 , the sub-server that lags significantly is identified according to the bandwidth sharing rule described above.",
"The identified sub-server gets to run its data handling process first at 1130 and thus put more data chunks into transmission queue.",
"Since transmission process will treat all transmission queues fairly, the sub-server that stores more data chunks into transmission queues get to use more bandwidth.",
"The process then loops back to 1125 .",
"If no sub-server significantly lags behind, the process proceeds to 1135 and the cluster counter is initialized.",
"The cluster counter is initialized to zero.",
"The cluster counter may be initialized to one, in which case the test at 1150 would be against n+1.",
"In yet another alternative embodiment the cluster counter may be initialized to the highest numbered cluster first and decremented.",
"Counter initialization and incrementation or decrementation is well known in the art.",
"The data handling process of the corresponding sub-server is executed at 1140 .",
"The cluster counter is incremented at 1145 and a test is performed at 1150 to determine if the last cluster head has been served in this round of service.",
"If the last cluster head has been served in this round of service, then processing looks back to 1120 .",
"[0046] The invention describe herein can achieve the maximum/optimal streaming rate allowed by the P2P system with the specific peer-to-peer overlay topology.",
"If a constant-bit-rate (CBR) video is streamed over such a P2P system, all peers/users can be supported as long as the constant bit rate is smaller than the maximum supportable streaming rate.",
"[0047] The invention described herein does not assume any knowledge of the underlying network topology or the support of a dedicated network infrastructure such as in-network cache proxies or CDN (content distribution network) edge servers.",
"If such information or infrastructure support is available, the decentralized HCPS (dHCPS) of the present invention is able to take advantage of such and deliver better user quality of experience (QoE).",
"For instance, if the network topology is known, dHCPS can group the close-by peers into the same cluster hence reduce the traffic load on the underlying network and shorten the propagation delays.",
"As another example, if in-network cache proxies or CDN edge servers are available to support the live streaming, dHCPS can use them as cluster heads since this dedicated network infrastructure typically has more upload capacity and are less likely to leave the network suddenly.",
"[0048] It is to be understood that the present invention may be implemented in various forms of hardware (e.g. ASIC chip), software, firmware, special purpose processors, or a combination thereof, for example, within a server, an intermediate device (such as a wireless access point, a wireless router, a set-top box, or mobile device).",
"Preferably, the present invention is implemented as a combination of hardware and software.",
"Moreover, the software is preferably implemented as an application program tangibly embodied on a program storage device.",
"The application program may be uploaded to, and executed by, a machine comprising any suitable architecture.",
"Preferably, the machine is implemented on a computer platform having hardware such as one or more central processing units (CPU), a random access memory (RAM), and input/output (I/O) interface(s).",
"The computer platform also includes an operating system and microinstruction code.",
"The various processes and functions described herein may either be part of the microinstruction code or part of the application program (or a combination thereof), which is executed via the operating system.",
"In addition, various other peripheral devices may be connected to the computer platform such as an additional data storage device and a printing device.",
"[0049] It is to be further understood that, because some of the constituent system components and method steps depicted in the accompanying figures are preferably implemented in software, the actual connections between the system components (or the process steps) may differ depending upon the manner in which the present invention is programmed.",
"Given the teachings herein, one of ordinary skill in the related art will be able to contemplate these and similar implementations or configurations of the present invention."
] |
FIELD
The subject matter disclosed herein generally relates to techniques to couple differential amplifiers.
DESCRIPTION OF RELATED ART
FIG. 1 depicts a prior art two stage differential amplifier. The RC time constant of this two stage differential amplifier is based on the resistances of RL 12 and RL 13 as well as the input capacitances of transistors Q 12 and Q 15 . The RC time constant limits the maximum speed of the prior art two stage differential amplifier. To lower this time constant, a well known emitter follower (not depicted) may be added to couple the differential amplifiers. However, by doing so the voltage across current source I 7 is lowered (e.g., by Vbe volts) and thereby may lower the voltage across current source I 7 to the point of not operating (e.g., lower the voltage at the emitter terminals of transistors Q 12 and Q 15 below a threshold operating voltage).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a prior art two stage amplifier;
FIG. 2 depicts a receiver system in accordance with an embodiment of the present invention;
FIG. 3 depicts an amplifier in accordance with an embodiment of the present invention;
FIG. 4 depicts an implementation of a coupling device in accordance with an embodiment of the present invention; and
FIG. 5 depicts an implementation of an amplifier in accordance with an embodiment of the present invention.
Note that use of the same reference numbers in different figures indicates the same or like elements.
DETAILED DESCRIPTION
FIG. 2 depicts a receiver system 20 in accordance with an embodiment of the present invention. Receiver system 20 may include optical-to-electrical converter (O/E) 22 , amplifier 24 , re-timer system 25 , data processor 26 , bus 27 , and interface 28 .
O/E 22 may convert optical signals to electrical format. In some embodiments of receiver system 20 , O/E 22 may not be used and electrical format signals are received by amplifier 24 . Amplifier 24 may amplify an electrical format input signal. For example, amplifier 24 may receive a small input current and convert such current to a small output voltage (e.g., in the order of millivolts). Amplifier 24 may use some embodiments of the present invention. Re-timer system 25 may reduce jitter in the amplified electrical signals.
Data processor 26 may perform optical transport network (OTN) de-framing and de-wrapping in compliance for example with ITU-T G.709; and/or forward error correction (FEC) processing in compliance for example with ITU-T G.975; and/or media access control (MAC) processing in compliance for example with Ethernet.
Bus 27 may provide intercommunication between re-timer system 25 and/or data processor 26 and other devices such as a memory device (not depicted) and/or microprocessor (not depicted). Bus 27 may comply with one or more of the following standards: Ten Gigabit Attachment Unit Interface (XAUI) (described in IEEE 802.3, IEEE 802.3ae, and related standards), Serial Peripheral Interface (SPI), I 2 C, universal serial bus (USB), IEEE 1394, Gigabit Media Independent Interface (GMII) (described in IEEE 802.3, IEEE 802.3ae, and related standards), Peripheral Component Interconnect (PCI), ten bit interface (TBI), and/or a vendor specific multi-source agreement (MSA) protocol.
Interface 28 may provide intercommunication between data processor 26 and other devices such as a packet processor (not depicted) and/or a switch fabric (not depicted). Interface 28 may comply with similar communications standards as that of bus 27 .
In one implementation, components of system 20 may be implemented as any or a combination of: hardwired logic, software stored by a memory device and executed by a microprocessor, firmware, an application specific integrated circuit (ASIC), and/or a field programmable gate array (FPGA). In one implementation, components of system 20 may be implemented among the same integrated circuit. In another implementation, components of system 20 may be implemented among several integrated circuits that intercommunicate using, for example, a bus or conductive leads of a printed circuit board.
FIG. 3 depicts an amplifier 100 in accordance with an embodiment of the present invention. One implementation of amplifier 100 may include input signal source 102 , differential amplifier 104 A, differential amplifier 104 B, coupling device 106 A, and coupling device 106 B. In one implementation, differential amplifiers 104 A and 104 B have similar characteristics and may be implemented in a similar manner. In one implementation, coupling devices 106 A and 106 B may have similar characteristics and may be implemented in a similar manner.
Terminal Y 2 of differential amplifier 104 A may provide an input to coupling device 106 A whereas terminal Y 2 N of differential amplifier 104 A may provide an input to coupling device 106 B. Outputs of coupling devices 106 A and 106 B may be coupled to respective differential inputs Y 22 and Y 22 N of differential amplifier 104 B. Differential amplifier 104 B may provide a differential output to terminals Out 2 and Out 2 N.
FIG. 4 depicts one possible implementation of each of coupling devices 106 A and 106 B in accordance with an embodiment of the present invention. This implementation may include transistor Q 1 , current source I 1 , capacitance element C 0 , and resistive element R 1 . Transistor Q 1 may be implemented as a bipolar junction transistor (BJT). A collector terminal of transistor Q 1 may be coupled to a voltage source Vdd. A base terminal of transistor Q 1 may be coupled to receive an input signal. An emitter terminal of transistor Q 1 may be coupled to current source I 1 . Current source I 1 may be coupled between an emitter terminal of transistor Q 1 and voltage terminal Vee. Capacitance element C 0 and resistive element R 1 may couple respective emitter and base terminals of transistor Q 1 to an output terminal.
FIG. 5 depicts an implementation of an amplifier in accordance with an embodiment of the present invention. The amplifier of FIG. 5 may include input signal source 102 , differential amplifier 104 A, differential amplifier 104 B, coupling device 106 A, and coupling device 106 B. Input signal source 102 may provide an input signal to differential amplifier 104 A.
One implementation of differential amplifier 104 A may include transistors Q 2 and Q 3 , current source I 2 , resistive element RL 1 , and resistive element RL 2 . Input signal source 102 may provide a differential input signal to terminals In 2 and In 2 N of respective transistors Q 2 and Q 3 . Transistors Q 2 and Q 3 may be implemented as bipolar junction transistors (BJT) having similar characteristics, although other transistors may be used. Collector terminals of transistors Q 2 and Q 3 may provide respective output terminals Y 2 and Y 2 N. Resistive elements RL 1 and RL 2 may couple collector terminals of transistors Q 2 and Q 3 to a DC voltage source, Vdd. A common mode voltage for the input signal provided to base terminals of transistors Q 2 and Q 3 may be the same as that at respective output terminals Y 2 and Y 2 N. Emitter terminals of transistors Q 2 and Q 3 may be coupled to current source I 2 . Terminal Y 2 of differential amplifier 104 A may provide an input to coupling device 106 A whereas terminal Y 2 N of differential amplifier 104 A may provide an input to coupling device 106 B.
Coupling devices 106 A and 106 B may couple nodes Y 2 and Y 2 N of differential amplifier 104 A to respective differential inputs Y 22 and Y 22 N of differential amplifier 104 B. Coupling devices 106 A and 106 B may be implemented as devices with similar characteristics. For example, coupling devices 106 A and 106 B may be implemented in a similar manner to the implementation shown in FIG. 4 . However, one implementation of coupling device 106 A may include transistor Q 18 , current source 110 , resistive element R 8 , and capacitive element C 2 . One implementation of coupling device 106 B may include transistor Q 19 , current source I 11 , resistive element R 9 , and capacitive element C 1 .
Resistive element R 8 of coupling device 106 A may transfer low frequency components of signals from node Y 2 to node Y 22 . Resistive element R 9 of coupling device 106 B may transfer low frequency components of signals from node Y 2 N to node Y 22 N. Capacitance element C 2 may transfer high frequency components of signals from node Y 2 to node Y 22 . Capacitance element C 1 may transfer high frequency components of signals from node Y 2 N to node Y 22 N. In one implementation, common mode voltages at Y 2 and Y 2 N may match those at nodes Y 22 and Y 22 N.
One advantage of this implementation, but not a necessary feature, is that the RC time constant at output terminals of differential amplifier 104 A may be lower than at the base terminals of Q 12 and Q 15 of the prior art two stage differential amplifier of FIG. 1 . One advantage of this implementation, but not a necessary feature, is that the switching speed of nodes Y 22 and Y 22 N may be faster than those of respective Q 12 and Q 15 of the prior art two stage differential amplifier of FIG. 1 .
Differential amplifier 104 B may be implemented in a similar manner as differential amplifier 104 A. For example, one implementation of differential amplifier 104 B may include transistors Q 4 and Q 5 , current source I 3 , resistive element RL 3 , and resistive element RL 4 . Input node Y 22 may be provided to a base terminal of transistor Q 5 whereas input node Y 22 N may be provided to a base terminal of transistor Q 4 . Collector terminals of transistors Q 4 and Q 5 may provide respective output terminals Out 2 and Out 2 N. Resistive elements RL 3 and RL 4 may couple collector terminals of transistors Q 4 and Q 5 to a DC voltage source, Vdd. Emitter terminals of transistors Q 4 and Q 5 may be coupled to current source I 3 .
The following parameters are merely examples and in no way limit the scope of the invention. In one implementation, resistive elements RL 1 , RL 2 , RL 3 , and RL 4 may each have resistance values of 250 ohms. In one implementation, resistive elements R 8 and R 9 may each have resistance values of 1,000 ohms. In one implementation, capacitance elements C 1 and C 2 each may have capacitance values of 300 femtofarads. In one implementation, transistors Q 2 , Q 3 , Q 4 , and Q 5 may have similar transistor characteristics. In one implementation, transistors Q 18 and Q 19 may have similar transistor characteristics. In one implementation, current sources I 10 and I 11 may each provide a current of 0.5 mA. In one implementation, current sources I 2 and I 3 may each provide a current of 1 mA. In one implementation, Vdd may have a value of 1.8 volts.
The drawings and the forgoing description gave examples of the present invention. The scope of the present invention, however, is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of the invention is at least as broad as given by the following claims. | Briefly, techniques to couple differential amplifiers with a low RC time constant and provide minimal common mode voltage reduction. | Summarize the key points of the given document. | [
"FIELD The subject matter disclosed herein generally relates to techniques to couple differential amplifiers.",
"DESCRIPTION OF RELATED ART FIG. 1 depicts a prior art two stage differential amplifier.",
"The RC time constant of this two stage differential amplifier is based on the resistances of RL 12 and RL 13 as well as the input capacitances of transistors Q 12 and Q 15 .",
"The RC time constant limits the maximum speed of the prior art two stage differential amplifier.",
"To lower this time constant, a well known emitter follower (not depicted) may be added to couple the differential amplifiers.",
"However, by doing so the voltage across current source I 7 is lowered (e.g., by Vbe volts) and thereby may lower the voltage across current source I 7 to the point of not operating (e.g., lower the voltage at the emitter terminals of transistors Q 12 and Q 15 below a threshold operating voltage).",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 depicts a prior art two stage amplifier;",
"FIG. 2 depicts a receiver system in accordance with an embodiment of the present invention;",
"FIG. 3 depicts an amplifier in accordance with an embodiment of the present invention;",
"FIG. 4 depicts an implementation of a coupling device in accordance with an embodiment of the present invention;",
"and FIG. 5 depicts an implementation of an amplifier in accordance with an embodiment of the present invention.",
"Note that use of the same reference numbers in different figures indicates the same or like elements.",
"DETAILED DESCRIPTION FIG. 2 depicts a receiver system 20 in accordance with an embodiment of the present invention.",
"Receiver system 20 may include optical-to-electrical converter (O/E) 22 , amplifier 24 , re-timer system 25 , data processor 26 , bus 27 , and interface 28 .",
"O/E 22 may convert optical signals to electrical format.",
"In some embodiments of receiver system 20 , O/E 22 may not be used and electrical format signals are received by amplifier 24 .",
"Amplifier 24 may amplify an electrical format input signal.",
"For example, amplifier 24 may receive a small input current and convert such current to a small output voltage (e.g., in the order of millivolts).",
"Amplifier 24 may use some embodiments of the present invention.",
"Re-timer system 25 may reduce jitter in the amplified electrical signals.",
"Data processor 26 may perform optical transport network (OTN) de-framing and de-wrapping in compliance for example with ITU-T G[.",
"].709;",
"and/or forward error correction (FEC) processing in compliance for example with ITU-T G[.",
"].975;",
"and/or media access control (MAC) processing in compliance for example with Ethernet.",
"Bus 27 may provide intercommunication between re-timer system 25 and/or data processor 26 and other devices such as a memory device (not depicted) and/or microprocessor (not depicted).",
"Bus 27 may comply with one or more of the following standards: Ten Gigabit Attachment Unit Interface (XAUI) (described in IEEE 802.3, IEEE 802.3ae, and related standards), Serial Peripheral Interface (SPI), I 2 C, universal serial bus (USB), IEEE 1394, Gigabit Media Independent Interface (GMII) (described in IEEE 802.3, IEEE 802.3ae, and related standards), Peripheral Component Interconnect (PCI), ten bit interface (TBI), and/or a vendor specific multi-source agreement (MSA) protocol.",
"Interface 28 may provide intercommunication between data processor 26 and other devices such as a packet processor (not depicted) and/or a switch fabric (not depicted).",
"Interface 28 may comply with similar communications standards as that of bus 27 .",
"In one implementation, components of system 20 may be implemented as any or a combination of: hardwired logic, software stored by a memory device and executed by a microprocessor, firmware, an application specific integrated circuit (ASIC), and/or a field programmable gate array (FPGA).",
"In one implementation, components of system 20 may be implemented among the same integrated circuit.",
"In another implementation, components of system 20 may be implemented among several integrated circuits that intercommunicate using, for example, a bus or conductive leads of a printed circuit board.",
"FIG. 3 depicts an amplifier 100 in accordance with an embodiment of the present invention.",
"One implementation of amplifier 100 may include input signal source 102 , differential amplifier 104 A, differential amplifier 104 B, coupling device 106 A, and coupling device 106 B. In one implementation, differential amplifiers 104 A and 104 B have similar characteristics and may be implemented in a similar manner.",
"In one implementation, coupling devices 106 A and 106 B may have similar characteristics and may be implemented in a similar manner.",
"Terminal Y 2 of differential amplifier 104 A may provide an input to coupling device 106 A whereas terminal Y 2 N of differential amplifier 104 A may provide an input to coupling device 106 B. Outputs of coupling devices 106 A and 106 B may be coupled to respective differential inputs Y 22 and Y 22 N of differential amplifier 104 B. Differential amplifier 104 B may provide a differential output to terminals Out 2 and Out 2 N. FIG. 4 depicts one possible implementation of each of coupling devices 106 A and 106 B in accordance with an embodiment of the present invention.",
"This implementation may include transistor Q 1 , current source I 1 , capacitance element C 0 , and resistive element R 1 .",
"Transistor Q 1 may be implemented as a bipolar junction transistor (BJT).",
"A collector terminal of transistor Q 1 may be coupled to a voltage source Vdd.",
"A base terminal of transistor Q 1 may be coupled to receive an input signal.",
"An emitter terminal of transistor Q 1 may be coupled to current source I 1 .",
"Current source I 1 may be coupled between an emitter terminal of transistor Q 1 and voltage terminal Vee.",
"Capacitance element C 0 and resistive element R 1 may couple respective emitter and base terminals of transistor Q 1 to an output terminal.",
"FIG. 5 depicts an implementation of an amplifier in accordance with an embodiment of the present invention.",
"The amplifier of FIG. 5 may include input signal source 102 , differential amplifier 104 A, differential amplifier 104 B, coupling device 106 A, and coupling device 106 B. Input signal source 102 may provide an input signal to differential amplifier 104 A. One implementation of differential amplifier 104 A may include transistors Q 2 and Q 3 , current source I 2 , resistive element RL 1 , and resistive element RL 2 .",
"Input signal source 102 may provide a differential input signal to terminals In 2 and In 2 N of respective transistors Q 2 and Q 3 .",
"Transistors Q 2 and Q 3 may be implemented as bipolar junction transistors (BJT) having similar characteristics, although other transistors may be used.",
"Collector terminals of transistors Q 2 and Q 3 may provide respective output terminals Y 2 and Y 2 N. Resistive elements RL 1 and RL 2 may couple collector terminals of transistors Q 2 and Q 3 to a DC voltage source, Vdd.",
"A common mode voltage for the input signal provided to base terminals of transistors Q 2 and Q 3 may be the same as that at respective output terminals Y 2 and Y 2 N. Emitter terminals of transistors Q 2 and Q 3 may be coupled to current source I 2 .",
"Terminal Y 2 of differential amplifier 104 A may provide an input to coupling device 106 A whereas terminal Y 2 N of differential amplifier 104 A may provide an input to coupling device 106 B. Coupling devices 106 A and 106 B may couple nodes Y 2 and Y 2 N of differential amplifier 104 A to respective differential inputs Y 22 and Y 22 N of differential amplifier 104 B. Coupling devices 106 A and 106 B may be implemented as devices with similar characteristics.",
"For example, coupling devices 106 A and 106 B may be implemented in a similar manner to the implementation shown in FIG. 4 .",
"However, one implementation of coupling device 106 A may include transistor Q 18 , current source 110 , resistive element R 8 , and capacitive element C 2 .",
"One implementation of coupling device 106 B may include transistor Q 19 , current source I 11 , resistive element R 9 , and capacitive element C 1 .",
"Resistive element R 8 of coupling device 106 A may transfer low frequency components of signals from node Y 2 to node Y 22 .",
"Resistive element R 9 of coupling device 106 B may transfer low frequency components of signals from node Y 2 N to node Y 22 N. Capacitance element C 2 may transfer high frequency components of signals from node Y 2 to node Y 22 .",
"Capacitance element C 1 may transfer high frequency components of signals from node Y 2 N to node Y 22 N. In one implementation, common mode voltages at Y 2 and Y 2 N may match those at nodes Y 22 and Y 22 N. One advantage of this implementation, but not a necessary feature, is that the RC time constant at output terminals of differential amplifier 104 A may be lower than at the base terminals of Q 12 and Q 15 of the prior art two stage differential amplifier of FIG. 1 .",
"One advantage of this implementation, but not a necessary feature, is that the switching speed of nodes Y 22 and Y 22 N may be faster than those of respective Q 12 and Q 15 of the prior art two stage differential amplifier of FIG. 1 .",
"Differential amplifier 104 B may be implemented in a similar manner as differential amplifier 104 A. For example, one implementation of differential amplifier 104 B may include transistors Q 4 and Q 5 , current source I 3 , resistive element RL 3 , and resistive element RL 4 .",
"Input node Y 22 may be provided to a base terminal of transistor Q 5 whereas input node Y 22 N may be provided to a base terminal of transistor Q 4 .",
"Collector terminals of transistors Q 4 and Q 5 may provide respective output terminals Out 2 and Out 2 N. Resistive elements RL 3 and RL 4 may couple collector terminals of transistors Q 4 and Q 5 to a DC voltage source, Vdd.",
"Emitter terminals of transistors Q 4 and Q 5 may be coupled to current source I 3 .",
"The following parameters are merely examples and in no way limit the scope of the invention.",
"In one implementation, resistive elements RL 1 , RL 2 , RL 3 , and RL 4 may each have resistance values of 250 ohms.",
"In one implementation, resistive elements R 8 and R 9 may each have resistance values of 1,000 ohms.",
"In one implementation, capacitance elements C 1 and C 2 each may have capacitance values of 300 femtofarads.",
"In one implementation, transistors Q 2 , Q 3 , Q 4 , and Q 5 may have similar transistor characteristics.",
"In one implementation, transistors Q 18 and Q 19 may have similar transistor characteristics.",
"In one implementation, current sources I 10 and I 11 may each provide a current of 0.5 mA.",
"In one implementation, current sources I 2 and I 3 may each provide a current of 1 mA.",
"In one implementation, Vdd may have a value of 1.8 volts.",
"The drawings and the forgoing description gave examples of the present invention.",
"The scope of the present invention, however, is by no means limited by these specific examples.",
"Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible.",
"The scope of the invention is at least as broad as given by the following claims."
] |
CROSS-REFERENCE TO RELATED APPLICATION
The present application is based on, and claims priority from, Japanese Application Serial Number JP2013-223427, filed Oct. 28, 2013, the disclosure of which is hereby incorporated by reference herein in its entirety.
TECHNICAL FIELD
The present invention relates to an over-the-head type dynamic headphone that is fitted to a head side part so as to cover an ear, and, more specifically, to a dynamic headphone on which a large-diameter headphone unit is mountable without an increase in size of a headphone case.
BACKGROUND ART
Headphones are classified broadly into three types, that is, an over-the-head type in which a headphone is held by a headband, an ear-hook type in which a headphone is held by being hooked on an ear, and an ear-insertion type in which a headphone is held by being directly inserted into an ear.
Among these types, the over-the-head type headphone is popular for the following reasons: high sound quality is obtained because of the use of a headphone case large enough to cover the entire ear; and even long-time fitting puts a low load on the ear.
According to a first conventional example of the over-the-head type headphone, as illustrated in FIG. 3A , an over-the-head type headphone 1 A includes a headphone band (not illustrated) that is fitted along a head H in an arch-like manner, and a headphone case 2 is suspended at each end of the headband.
A headphone unit 3 is housed in the headphone case 2 while being supported by a baffle plate 4 . A doughnut-shaped ear pad 5 to be placed around an ear E at the time of fitting of the headphone is integrally attached to a sound emitting surface of the headphone case 2 . In many cases, a dynamic electro-acoustic transducer is adopted for the headphone unit 3 .
In the headphone case 2 , a back air chamber C 2 having a predetermined volume is formed by the baffle plate 4 on a back side of the headphone unit 3 , and a substantially hermetically sealed front air chamber C 1 is formed by the ear pad 5 also on a front side of the headphone unit 3 at the time of fitting of the headphone.
In the headphone 1 A of this type, the following is a common practice to attenuate in-head localization of sound images and improve sound quality and frequency response. That is, an acoustic channel 6 is provided to part of the baffle plate 4 , an acoustic resistance material 6 a such as non-woven fabric is attached to the acoustic channel 6 , and the front air chamber C 1 and the back air chamber C 2 are acoustically connected to each other.
Meanwhile, in order to obtain a headphone having excellent sound quality, it is preferable to increase the diameter of the headphone unit 3 as much as possible. If a large-diameter headphone unit 3 is mounted as it is on the headphone 1 A having the configuration illustrated in FIG. 3A , however, the size of the headphone case 2 increases accordingly, and the portability thereof is impaired.
For the purpose of avoiding the portability thereof from being impaired, in order to mount the large-diameter headphone unit 3 without such an increase in size of the headphone case 2 , the acoustic channel 6 provided to the baffle plate 4 needs to be placed in the vicinity of the lower side of the ear pad 5 (the side of the ear pad 5 opposed to the baffle plate 4 ).
If such a design is adopted, however, the acoustic channel 6 may be closed by the ear pad 5 , depending on a lateral pressure applied when the headphone is fitted to the head H.
In view of the above, in a headphone 1 B (second conventional example) according to an invention described in Japanese Patent Application Publication No. 2013-42382, which is illustrated in FIG. 3B , in order to make a larger-diameter headphone unit 3 mountable, a communication groove 4 a is formed in the baffle plate 4 in the case where the acoustic channel 6 provided to the baffle plate 4 is placed on the lower side of the ear pad 5 . The communication groove 4 a is communicated with the acoustic channel 6 , and is deep enough not to be closed by the ear pad 5 .
According to Japanese Patent Application Publication No. 2013-42382, it is possible to provide a headphone that has a small size but includes the large-diameter headphone unit 3 , in which the acoustic channel 6 is hardly closed by the ear pad 5 . However, because the headphone still includes the baffle plate 4 , there is a limit to an increase in diameter of the headphone unit 3 . Moreover, because it is necessary to form, in the baffle plate 4 , the communication groove 4 a that is deep enough not to be closed by the ear pad 5 , production costs become higher accordingly.
Under the circumstances, the present invention has an object to provide a dynamic headphone that has a small size but makes a larger-diameter headphone unit mountable thereon, the dynamic headphone including a highly reliable acoustic channel that acoustically connects a front air chamber and a back air chamber to each other.
SUMMARY OF THE INVENTION
In order to achieve the above-mentioned object, the present invention provides a dynamic headphone including: a headphone unit including: a diaphragm including a voice coil; a magnetic circuit portion including a magnetic gap in which the voice coil is placed; and a unit frame that supports the diaphragm and the magnetic circuit portion; a headphone case that houses the headphone unit therein while securing a back air chamber having a predetermined volume on a back side of the headphone unit; an ear pad that is provided to an outer peripheral edge part of the headphone case so as to: surround an ear on a sound emitting surface side of the headphone unit; and form a front air chamber having a predetermined volume on a front side of the headphone unit, when the dynamic headphone is fitted to a head side part of a human body; and an acoustic channel that acoustically connects the front air chamber and the back air chamber to each other. The headphone case includes: a back air chamber forming portion that forms the back air chamber; and a mount portion integrally provided to an opening end of the back air chamber forming portion, the headphone unit being mounted in the mount portion. The acoustic channel is provided between the mount portion and the headphone unit.
According to a preferable aspect of the present invention, the mount portion includes: a cylindrical portion having a diameter larger than that of the unit frame; and an engagement portion that is bent inward from a front end of the cylindrical portion so as to be opposed to a peripheral edge part of the unit frame, and the acoustic channel is placed along inner surfaces of the engagement portion and the cylindrical portion.
Moreover, the present invention includes, as preferable aspects: an aspect in which a predetermined acoustic resistance material is provided in the acoustic channel; and an aspect in which the ear pad is provided on an outer surface side of the engagement portion.
According to the present invention, the headphone case includes: the dome portion that substantially forms the back air chamber; and the mount portion integrally provided to the opening end of the dome portion, the headphone unit being mounted in the mount portion. Hence, the headphone unit is directly mounted in the mount portion, and a baffle plate is not necessary, whereby a larger-diameter headphone unit can be mounted. Moreover, because the acoustic channel is provided between the mount portion and the headphone unit, the acoustic channel is not closed by the ear pad and the like, and thus has high reliability.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a main part cross-sectional view illustrating a dynamic headphone according to an embodiment of the present invention;
FIG. 2 is an exploded perspective view schematically illustrating a structure of the dynamic headphone;
FIG. 3A is a main part cross-sectional view illustrating a first conventional example; and
FIG. 3B is a main part cross-sectional view illustrating a second conventional example.
DETAILED DESCRIPTION
An embodiment of the present invention is described with reference to FIG. 1 and FIG. 2 , and the present invention is not limited to the embodiment.
As illustrated in FIG. 1 , a dynamic headphone 10 according to the present embodiment is of over-the-head type, and includes a headphone case 20 that is suspended at each end of a headband (not illustrated) with the intermediation of a universal-joint-like hanger member (not illustrated). The headband is fitted along a head H of a user from a head top part to each head side part. Note that a pair of right and left headphone cases 20 is supported by the headband, and only one thereof is illustrated in FIG. 1 , because the right and left headphone cases 20 have the same configuration as each other.
The headband may be a general U-shaped headband that is fitted along the head H from the head top part to each head side part, and may also be, for example, of behind-the-head type in which the headphone is held by fitting the headband along a head back part.
In the present embodiment, the headphone case 20 includes: a mount portion 30 in which a headphone unit 50 is mounted; and a dome portion 40 formed in a substantially cup shape, the dome portion 40 corresponding to a back air chamber forming portion that forms a back air chamber C 2 having a predetermined volume on a back side of the headphone unit 50 . The mount portion 30 is integrally attached to an opening end of the dome portion 40 . The material of each of the mount portion 30 and the dome portion 40 may be selected from synthetic resin materials, metal materials, and wood materials.
The headphone unit 50 is a dynamic electro-acoustic transducer, and includes a diaphragm 51 , a magnetic circuit portion 52 for driving, and a unit frame 53 that supports the diaphragm 51 and the magnetic circuit portion 52 .
The diaphragm 51 includes a center dome 511 and a sub-dome (also referred to as edge portion) 512 that is integrally provided in a continuous manner around the center dome 511 . A voice coil 513 is integrally attached using an adhesive or the like to a joint part between the center dome 511 and the sub-dome 512 , on a back side of the diaphragm 51 .
The magnetic circuit portion 52 includes: a dish-like yoke 521 formed in a substantially U-shape in cross-section; and a discoid permanent magnet 522 that is placed in a bottom part of the yoke 521 and is magnetized in a plate thickness direction. A pole piece 523 is provided on the permanent magnet 522 , and the pole piece 523 forms a magnetic gap G having a predetermined width between the pole piece 523 and an inner peripheral surface of the yoke 521 .
The entire unit frame 53 is formed in a discoid shape. The unit frame 53 includes, in the center thereof, an opening portion 531 that houses and supports the magnetic circuit portion 52 and is made of a cylindrical sleeve. A peripheral edge part of the sub-dome 512 of the diaphragm 51 is supported by a peripheral edge part of the unit frame 53 such that the voice coil 513 can vibrate in the magnetic gap G of the magnetic circuit portion 52 .
Moreover, the unit frame 53 is provided with a plurality of communication holes 532 for communicating an air chamber on the back side of the diaphragm 51 with the back air chamber C 2 . An acoustic resistance material 533 such as non-woven fabric is attached to each communication hole 532 , whereby predetermined damping is applied to the diaphragm 51 .
Further, a protector 54 having a large number of through-holes 541 for protecting the diaphragm 51 is provided on a front surface (in FIG. 1 , a left surface) of the unit frame 53 . Perforated metal, metal mesh (guard mesh), and the like may be used for the protector 54 . In the present embodiment, a sleeve 534 into which the protector 54 is fitted is provided in a standing manner to the peripheral edge part of the unit frame 53 .
Also with reference to FIG. 2 , the mount portion 30 includes: a cylindrical portion 31 having a diameter larger than that of the unit frame 53 ; and an engagement portion 32 for receiving the unit frame 53 , the engagement portion 32 being bent inward (toward the center of the cylindrical portion 31 ) from a front end (in FIG. 1 and FIG. 2 , a left end) of the cylindrical portion 31 so as to be opposed to the peripheral edge part of the unit frame 53 .
In the present embodiment, as illustrated in FIG. 2 , the engagement portion 32 is formed in a circular plate (washer-like shape) having an opened central part, and may be made of a plurality of nail pieces that are bent inward at predetermined intervals from the front end of the cylindrical portion 31 .
Moreover, although the engagement portion 32 is bent from the front end of the cylindrical portion 31 in the present embodiment, the engagement portion 32 may be formed as an independent member, and may be joined to the front end of the cylindrical portion 31 by using an adhesive, welding, or the like.
In the present embodiment, an ear pad 60 is integrally attached to an outer surface of the engagement portion 32 . The ear pad 60 may be a pad obtained by covering a cushioned foam core 61 formed in an annular shape with, for example, a cover material 62 made of synthetic leather.
At the time of fitting of the headphone, the ear pad 60 is pressed against the head side part at a predetermined lateral pressure applied by the headband so as to surround the ear E, whereby a substantially hermetically sealed front air chamber C 1 is formed on a front side of the headphone unit 50 .
In the case where the headphone unit 50 is mounted in the mount portion 30 , in the present invention, a baffle plate is not necessary, and the headphone unit 50 is directly housed in the mount portion 30 .
Moreover, an acoustic channel (an acoustic channel that acoustically connects the front air chamber C 1 and the back air chamber C 2 to each other) 70 for attenuating in-head localization of sound images and improving sound quality and frequency response is provided in the mount portion 30 .
Accordingly, in the present embodiment, because the cylindrical portion 31 of the mount portion 30 has a diameter larger than that of the unit frame 53 of the headphone unit 50 , for example, an acoustic resistance material 71 that is made of felt or the like and has an L-shape in cross-section is provided in an annular shape to an inner surface of the cylindrical portion 31 and an inner surface of the engagement portion 32 , and the headphone unit 50 is then mounted (housed) in the mount portion 30 , whereby the acoustic channel 70 is formed. It is assumed that the respective widths of the annular parts of the ear pad 60 and the acoustic resistance material 71 and the width of the engagement portion 32 are the same as illustrated in FIG. 1 .
According to this configuration, the headphone unit 50 having a large diameter close to the outer diameter of the ear pad 60 can be mounted. Moreover, because the acoustic channel 70 is placed in the mount portion 30 that is not influenced by the ear pad 60 , the acoustic channel 70 having high reliability can be secured.
In the above-mentioned embodiment, a gap serving as the acoustic channel 70 is provided between the mount portion 30 and the unit frame 53 by means of the acoustic resistance material 71 . Alternatively, according to another embodiment, for example, ribs each having a predetermined height may be formed on the inner surfaces of the cylindrical portion 31 and the engagement portion 32 , the acoustic channel 70 may be defined by a gap formed by the ribs, and the acoustic resistance material 71 having a predetermined acoustic resistance value may be placed in the acoustic channel 70 . Such an embodiment is also included in the present invention.
Moreover, in the above-mentioned embodiment, the back air chamber C 2 is substantially formed by the cup-shaped dome portion 40 . Alternatively, according to another embodiment, the cylindrical portion 31 of the mount portion 30 may be extended in the axial direction by a predetermined length up to the back side of the headphone unit 50 , and a back end part of the cylindrical portion 31 may be included in an element for forming the back air chamber C 2 .
According to the another embodiment, the back air chamber forming portion is constituted by the dome portion 40 and part of the mount portion 30 . Still alternatively, the back end part of the cylindrical portion 31 of the mount portion 30 may be closed by a cover plate or the like, whereby the back air chamber C 2 may be formed. In this case, the dome portion 40 is not necessary, and hence the back air chamber forming portion is constituted by the mount portion 30 . | Provided is a dynamic headphone that has a small size but makes a larger-diameter headphone unit mountable thereon, the dynamic headphone including a highly reliable acoustic channel that acoustically connects a front air chamber and a back air chamber to each other. A headphone case 20 houses a headphone unit 50 therein, and includes a back air chamber C 2 on a back side of the headphone unit 50 . The headphone case 20 includes: a back air chamber forming portion 40 that forms the back air chamber C 2 ; and a mount portion 30 integrally provided to an opening end of the back air chamber forming portion 40 , the headphone unit 50 being mounted in the mount portion 30 . An acoustic channel 70 is provided between the mount portion 30 and the headphone unit 50. | Concisely explain the essential features and purpose of the invention. | [
"CROSS-REFERENCE TO RELATED APPLICATION The present application is based on, and claims priority from, Japanese Application Serial Number JP2013-223427, filed Oct. 28, 2013, the disclosure of which is hereby incorporated by reference herein in its entirety.",
"TECHNICAL FIELD The present invention relates to an over-the-head type dynamic headphone that is fitted to a head side part so as to cover an ear, and, more specifically, to a dynamic headphone on which a large-diameter headphone unit is mountable without an increase in size of a headphone case.",
"BACKGROUND ART Headphones are classified broadly into three types, that is, an over-the-head type in which a headphone is held by a headband, an ear-hook type in which a headphone is held by being hooked on an ear, and an ear-insertion type in which a headphone is held by being directly inserted into an ear.",
"Among these types, the over-the-head type headphone is popular for the following reasons: high sound quality is obtained because of the use of a headphone case large enough to cover the entire ear;",
"and even long-time fitting puts a low load on the ear.",
"According to a first conventional example of the over-the-head type headphone, as illustrated in FIG. 3A , an over-the-head type headphone 1 A includes a headphone band (not illustrated) that is fitted along a head H in an arch-like manner, and a headphone case 2 is suspended at each end of the headband.",
"A headphone unit 3 is housed in the headphone case 2 while being supported by a baffle plate 4 .",
"A doughnut-shaped ear pad 5 to be placed around an ear E at the time of fitting of the headphone is integrally attached to a sound emitting surface of the headphone case 2 .",
"In many cases, a dynamic electro-acoustic transducer is adopted for the headphone unit 3 .",
"In the headphone case 2 , a back air chamber C 2 having a predetermined volume is formed by the baffle plate 4 on a back side of the headphone unit 3 , and a substantially hermetically sealed front air chamber C 1 is formed by the ear pad 5 also on a front side of the headphone unit 3 at the time of fitting of the headphone.",
"In the headphone 1 A of this type, the following is a common practice to attenuate in-head localization of sound images and improve sound quality and frequency response.",
"That is, an acoustic channel 6 is provided to part of the baffle plate 4 , an acoustic resistance material 6 a such as non-woven fabric is attached to the acoustic channel 6 , and the front air chamber C 1 and the back air chamber C 2 are acoustically connected to each other.",
"Meanwhile, in order to obtain a headphone having excellent sound quality, it is preferable to increase the diameter of the headphone unit 3 as much as possible.",
"If a large-diameter headphone unit 3 is mounted as it is on the headphone 1 A having the configuration illustrated in FIG. 3A , however, the size of the headphone case 2 increases accordingly, and the portability thereof is impaired.",
"For the purpose of avoiding the portability thereof from being impaired, in order to mount the large-diameter headphone unit 3 without such an increase in size of the headphone case 2 , the acoustic channel 6 provided to the baffle plate 4 needs to be placed in the vicinity of the lower side of the ear pad 5 (the side of the ear pad 5 opposed to the baffle plate 4 ).",
"If such a design is adopted, however, the acoustic channel 6 may be closed by the ear pad 5 , depending on a lateral pressure applied when the headphone is fitted to the head H. In view of the above, in a headphone 1 B (second conventional example) according to an invention described in Japanese Patent Application Publication No. 2013-42382, which is illustrated in FIG. 3B , in order to make a larger-diameter headphone unit 3 mountable, a communication groove 4 a is formed in the baffle plate 4 in the case where the acoustic channel 6 provided to the baffle plate 4 is placed on the lower side of the ear pad 5 .",
"The communication groove 4 a is communicated with the acoustic channel 6 , and is deep enough not to be closed by the ear pad 5 .",
"According to Japanese Patent Application Publication No. 2013-42382, it is possible to provide a headphone that has a small size but includes the large-diameter headphone unit 3 , in which the acoustic channel 6 is hardly closed by the ear pad 5 .",
"However, because the headphone still includes the baffle plate 4 , there is a limit to an increase in diameter of the headphone unit 3 .",
"Moreover, because it is necessary to form, in the baffle plate 4 , the communication groove 4 a that is deep enough not to be closed by the ear pad 5 , production costs become higher accordingly.",
"Under the circumstances, the present invention has an object to provide a dynamic headphone that has a small size but makes a larger-diameter headphone unit mountable thereon, the dynamic headphone including a highly reliable acoustic channel that acoustically connects a front air chamber and a back air chamber to each other.",
"SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a dynamic headphone including: a headphone unit including: a diaphragm including a voice coil;",
"a magnetic circuit portion including a magnetic gap in which the voice coil is placed;",
"and a unit frame that supports the diaphragm and the magnetic circuit portion;",
"a headphone case that houses the headphone unit therein while securing a back air chamber having a predetermined volume on a back side of the headphone unit;",
"an ear pad that is provided to an outer peripheral edge part of the headphone case so as to: surround an ear on a sound emitting surface side of the headphone unit;",
"and form a front air chamber having a predetermined volume on a front side of the headphone unit, when the dynamic headphone is fitted to a head side part of a human body;",
"and an acoustic channel that acoustically connects the front air chamber and the back air chamber to each other.",
"The headphone case includes: a back air chamber forming portion that forms the back air chamber;",
"and a mount portion integrally provided to an opening end of the back air chamber forming portion, the headphone unit being mounted in the mount portion.",
"The acoustic channel is provided between the mount portion and the headphone unit.",
"According to a preferable aspect of the present invention, the mount portion includes: a cylindrical portion having a diameter larger than that of the unit frame;",
"and an engagement portion that is bent inward from a front end of the cylindrical portion so as to be opposed to a peripheral edge part of the unit frame, and the acoustic channel is placed along inner surfaces of the engagement portion and the cylindrical portion.",
"Moreover, the present invention includes, as preferable aspects: an aspect in which a predetermined acoustic resistance material is provided in the acoustic channel;",
"and an aspect in which the ear pad is provided on an outer surface side of the engagement portion.",
"According to the present invention, the headphone case includes: the dome portion that substantially forms the back air chamber;",
"and the mount portion integrally provided to the opening end of the dome portion, the headphone unit being mounted in the mount portion.",
"Hence, the headphone unit is directly mounted in the mount portion, and a baffle plate is not necessary, whereby a larger-diameter headphone unit can be mounted.",
"Moreover, because the acoustic channel is provided between the mount portion and the headphone unit, the acoustic channel is not closed by the ear pad and the like, and thus has high reliability.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a main part cross-sectional view illustrating a dynamic headphone according to an embodiment of the present invention;",
"FIG. 2 is an exploded perspective view schematically illustrating a structure of the dynamic headphone;",
"FIG. 3A is a main part cross-sectional view illustrating a first conventional example;",
"and FIG. 3B is a main part cross-sectional view illustrating a second conventional example.",
"DETAILED DESCRIPTION An embodiment of the present invention is described with reference to FIG. 1 and FIG. 2 , and the present invention is not limited to the embodiment.",
"As illustrated in FIG. 1 , a dynamic headphone 10 according to the present embodiment is of over-the-head type, and includes a headphone case 20 that is suspended at each end of a headband (not illustrated) with the intermediation of a universal-joint-like hanger member (not illustrated).",
"The headband is fitted along a head H of a user from a head top part to each head side part.",
"Note that a pair of right and left headphone cases 20 is supported by the headband, and only one thereof is illustrated in FIG. 1 , because the right and left headphone cases 20 have the same configuration as each other.",
"The headband may be a general U-shaped headband that is fitted along the head H from the head top part to each head side part, and may also be, for example, of behind-the-head type in which the headphone is held by fitting the headband along a head back part.",
"In the present embodiment, the headphone case 20 includes: a mount portion 30 in which a headphone unit 50 is mounted;",
"and a dome portion 40 formed in a substantially cup shape, the dome portion 40 corresponding to a back air chamber forming portion that forms a back air chamber C 2 having a predetermined volume on a back side of the headphone unit 50 .",
"The mount portion 30 is integrally attached to an opening end of the dome portion 40 .",
"The material of each of the mount portion 30 and the dome portion 40 may be selected from synthetic resin materials, metal materials, and wood materials.",
"The headphone unit 50 is a dynamic electro-acoustic transducer, and includes a diaphragm 51 , a magnetic circuit portion 52 for driving, and a unit frame 53 that supports the diaphragm 51 and the magnetic circuit portion 52 .",
"The diaphragm 51 includes a center dome 511 and a sub-dome (also referred to as edge portion) 512 that is integrally provided in a continuous manner around the center dome 511 .",
"A voice coil 513 is integrally attached using an adhesive or the like to a joint part between the center dome 511 and the sub-dome 512 , on a back side of the diaphragm 51 .",
"The magnetic circuit portion 52 includes: a dish-like yoke 521 formed in a substantially U-shape in cross-section;",
"and a discoid permanent magnet 522 that is placed in a bottom part of the yoke 521 and is magnetized in a plate thickness direction.",
"A pole piece 523 is provided on the permanent magnet 522 , and the pole piece 523 forms a magnetic gap G having a predetermined width between the pole piece 523 and an inner peripheral surface of the yoke 521 .",
"The entire unit frame 53 is formed in a discoid shape.",
"The unit frame 53 includes, in the center thereof, an opening portion 531 that houses and supports the magnetic circuit portion 52 and is made of a cylindrical sleeve.",
"A peripheral edge part of the sub-dome 512 of the diaphragm 51 is supported by a peripheral edge part of the unit frame 53 such that the voice coil 513 can vibrate in the magnetic gap G of the magnetic circuit portion 52 .",
"Moreover, the unit frame 53 is provided with a plurality of communication holes 532 for communicating an air chamber on the back side of the diaphragm 51 with the back air chamber C 2 .",
"An acoustic resistance material 533 such as non-woven fabric is attached to each communication hole 532 , whereby predetermined damping is applied to the diaphragm 51 .",
"Further, a protector 54 having a large number of through-holes 541 for protecting the diaphragm 51 is provided on a front surface (in FIG. 1 , a left surface) of the unit frame 53 .",
"Perforated metal, metal mesh (guard mesh), and the like may be used for the protector 54 .",
"In the present embodiment, a sleeve 534 into which the protector 54 is fitted is provided in a standing manner to the peripheral edge part of the unit frame 53 .",
"Also with reference to FIG. 2 , the mount portion 30 includes: a cylindrical portion 31 having a diameter larger than that of the unit frame 53 ;",
"and an engagement portion 32 for receiving the unit frame 53 , the engagement portion 32 being bent inward (toward the center of the cylindrical portion 31 ) from a front end (in FIG. 1 and FIG. 2 , a left end) of the cylindrical portion 31 so as to be opposed to the peripheral edge part of the unit frame 53 .",
"In the present embodiment, as illustrated in FIG. 2 , the engagement portion 32 is formed in a circular plate (washer-like shape) having an opened central part, and may be made of a plurality of nail pieces that are bent inward at predetermined intervals from the front end of the cylindrical portion 31 .",
"Moreover, although the engagement portion 32 is bent from the front end of the cylindrical portion 31 in the present embodiment, the engagement portion 32 may be formed as an independent member, and may be joined to the front end of the cylindrical portion 31 by using an adhesive, welding, or the like.",
"In the present embodiment, an ear pad 60 is integrally attached to an outer surface of the engagement portion 32 .",
"The ear pad 60 may be a pad obtained by covering a cushioned foam core 61 formed in an annular shape with, for example, a cover material 62 made of synthetic leather.",
"At the time of fitting of the headphone, the ear pad 60 is pressed against the head side part at a predetermined lateral pressure applied by the headband so as to surround the ear E, whereby a substantially hermetically sealed front air chamber C 1 is formed on a front side of the headphone unit 50 .",
"In the case where the headphone unit 50 is mounted in the mount portion 30 , in the present invention, a baffle plate is not necessary, and the headphone unit 50 is directly housed in the mount portion 30 .",
"Moreover, an acoustic channel (an acoustic channel that acoustically connects the front air chamber C 1 and the back air chamber C 2 to each other) 70 for attenuating in-head localization of sound images and improving sound quality and frequency response is provided in the mount portion 30 .",
"Accordingly, in the present embodiment, because the cylindrical portion 31 of the mount portion 30 has a diameter larger than that of the unit frame 53 of the headphone unit 50 , for example, an acoustic resistance material 71 that is made of felt or the like and has an L-shape in cross-section is provided in an annular shape to an inner surface of the cylindrical portion 31 and an inner surface of the engagement portion 32 , and the headphone unit 50 is then mounted (housed) in the mount portion 30 , whereby the acoustic channel 70 is formed.",
"It is assumed that the respective widths of the annular parts of the ear pad 60 and the acoustic resistance material 71 and the width of the engagement portion 32 are the same as illustrated in FIG. 1 .",
"According to this configuration, the headphone unit 50 having a large diameter close to the outer diameter of the ear pad 60 can be mounted.",
"Moreover, because the acoustic channel 70 is placed in the mount portion 30 that is not influenced by the ear pad 60 , the acoustic channel 70 having high reliability can be secured.",
"In the above-mentioned embodiment, a gap serving as the acoustic channel 70 is provided between the mount portion 30 and the unit frame 53 by means of the acoustic resistance material 71 .",
"Alternatively, according to another embodiment, for example, ribs each having a predetermined height may be formed on the inner surfaces of the cylindrical portion 31 and the engagement portion 32 , the acoustic channel 70 may be defined by a gap formed by the ribs, and the acoustic resistance material 71 having a predetermined acoustic resistance value may be placed in the acoustic channel 70 .",
"Such an embodiment is also included in the present invention.",
"Moreover, in the above-mentioned embodiment, the back air chamber C 2 is substantially formed by the cup-shaped dome portion 40 .",
"Alternatively, according to another embodiment, the cylindrical portion 31 of the mount portion 30 may be extended in the axial direction by a predetermined length up to the back side of the headphone unit 50 , and a back end part of the cylindrical portion 31 may be included in an element for forming the back air chamber C 2 .",
"According to the another embodiment, the back air chamber forming portion is constituted by the dome portion 40 and part of the mount portion 30 .",
"Still alternatively, the back end part of the cylindrical portion 31 of the mount portion 30 may be closed by a cover plate or the like, whereby the back air chamber C 2 may be formed.",
"In this case, the dome portion 40 is not necessary, and hence the back air chamber forming portion is constituted by the mount portion 30 ."
] |
DISCLOSURE OF THE INVENTION
The present invention relates to a device for projecting light spots onto a surface.
More particularly, the present invention relates to a device of said type, which allows light spots having a shape and size which are constant on a plane or curved surface to be projected, at a varying distance and slope.
The projection of light spots onto surfaces is particularly, though not exclusively, applied in apparatuses for measuring human visual range, in particular in the apparatuses called "perimeters".
In these instruments the projection surface is a white hemispherical dome, at the center of which the patient's eye is to be placed.
Consequently, the system for projecting the spots onto the hemispherical dome turns out to be off centre.
As is well known, an accurate measurement of the visual range is of a great importance in ophthalmology, in the diagnosis and in the "follow-up" of several diseases, particularly in glaucoma.
Visual range is the visibility threshold in the various spatial directions with respect to the stared point.
During the examination of the visual range, a patient has to fix his eyes on a point at the center of a white hemispherical dome upon which luminous stimuli, or light spots, are projected from the periphery to the center of the hemispherical dome.
In the "kinetic" perimetry, the patient must press a button as soon as he sees a stimulus which moves from the periphery to the center of the visual range, whereas in the "static" perimetry static stimuli of a higher and higher brightness are projected until the patient presses the button.
The combination of the "visual points" on the whole range makes up a map of the visual range.
In Goldmann's perimeter, realized in 1945, which is still referred to as a standard, the hemispherical dome has a 33 cm radius and light spots of 0.01 to 1000 Apostilb, having surfaces of 1/16, 1/4, 1, 4, 16, 64 mm 2 (spot: O, I, II, III, IV and V) are projected onto the ground, which is uniformly lit at 31.5 Apostilb. An arm pivoted on the vertical axis of the hemispherical dome, which turns behind the patient's head, brings a lens so inclined and orientable as to be able to project the light spot onto any point in the hemispherical dome, while keeping at the same distance and slope with respect to its surface. As a consequence the light spot results always to be elliptic, but of a constant shape and size, and the projector does not require a continuous focusing.
Computer-controlled automatic perimeters have been realized, based upon the same principle of Goldmann's one, in the subsequent developments of these apparatuses.
The main problems found in their realization are pertinent to the driving, due to encumbrance, and to the displacement of the projection mechanism from the right to the left side. Some examples as regards the above are the perimeter PERIKON Optikon, and patents U.S. Pat. No. 3,414,348, U.S. Pat. No. 4,145,123, U.S. Pat. No. 4,260,227 and U.S. Pat. No. 3,664,732.
Subsequently, in many perimeters, the projection criterion of Goldmann has been abandoned for the lighter systems, which comprise a movable mirror housed in the hemispherical dome out of the visual range, generally above the head of the patient, as for instance in the patents EU 0,242,723, U.S. Pat. No. 4,561,738 and in the perimeters Octopus and Squid. Owing, however, to the different distance between this mirror and the various points of the dome, and to the oblique incidence of the projected ray onto its surface, the light spots which are obtained with these devices haven't a constant shape.
Some perimeters in which a larger dome has been adopted, out of Goldmann's standard, have been realized, such as the perimeters Octopus Interzeag, in order to reduce such shortcoming to a minimum.
Still in other perimeters, as for instance the perimeter Bausch & Lomb FIELDMASTER 5000, fewer mirrors to put away the projector have been used, and the orientable mirror has been placed almost in contact with the forehead of the patient, in order to reduce the relative differences of the path of the beam. The problem has been however so added of a lower light yield of the projector and therefore of the necessity for employing more powerful lamps, fans, etc.
In such perimeters the light beam passes through holes of not a negligible size, located in the visual range, to contain the size of the orientable mirror.
The more recent perimeters are generally magnifycation-and spot-focusing-compensated.
In a few instances (U.S. Pat. No. 4,561,738, Humoured) the well-known property of a telescope of having a magnification ratio between the object and the image which is equal to the ratio between the two lenses and is independent of distance is exploited, by arranging the object-light spot in the conjugate position with respect to that of the projected image.
In another patent (Patent EU 0,242,723, Techna Vision) a double couple of movable mirrors at 45° is interposed, which compensates for the differences of the optical path, keeping at the same time either magnification and focusing.
Either system, however, does not take into account the fact that the light spot on an oblique surface turns out to be distorted.
Because the projectors of the perimeters realized according to the latest patents have a projection head which in definitive is larger and more displaced off the center than in the preceding perimeters, in a few points the light spot results to be much more distorted than in other points, with a change in the surface of the 20% and more.
Moreover, the particular realization of most projectors described heretofore limits the application thereof to the only static or kinetic perimetry, and such projectors often result to be slow or noisy, with the prejudice of the foreseeability of the stimulus, which makes the test's result less reliable.
Finally, the projectors of the automatic perimeters heretofore realized do not provide any system that allows the intermittency of the light to be regulated, to measure the critical frequency of fusion of the patient in the various points of the visual range.
Such a type of test (flicker perimetry), though it is ascertained that it would furnish a useful information for the diagnosis of glaucoma, has always relied upon instruments that do not guarantee standard or reproducible test conditions.
In view of the above-mentioned problems, the Applicant suggests to realize a device for projecting light spots which is able to obviate all the mentioned drawbacks.
The primary object of the present invention is to provide a device of said type which is able to project circular light spots of constant shape and size, by virtue of being endowed of mechanisms compensating for the shape and the size of the light spot themselves projected in the dome indpendently of the the distance and of the inclination of the latter with respect to the projector itself.
It is still an object of the present invention to provide a device which is adoptable on perimeters realized either with a telescopic projection system, or with a double couple of movable mirrors.
A further object of the present invention is to realize a device that allows either the kinetic and the static perimetry to be carried out.
Another object of the present invention is to obtain a device endowed with a system for regulating the intermittency, to measure the critical frequency of fusion of the patient in the various points of the visual range.
It is therefore a specific object of the present invention a device for projecting light spots onto a surface, which device comprises a device for producing and concentrating light, a pierced member, which is movable before said device and is endowed with means for selecting a hole to be aligned with the light, an assembly of lenses and mirrors and a projection head for projecting the light onto a surface, and a shutter member, which regulates the projection of the light beam itself, in which device means for orienting said pierced member around the vertical axis passing through the center of the selected hole and means for orienting the same pierced member around the horizontal axis passing through the center of the selected hole are provided; the orientation and the position of the pierced member, as well as the selection of the hole and of the orientation of the projection head being obtained by a computer.
Between the device for generating and concentrating the light and the pierced member a circular filter may be provided, which is preferably inclined with respect to the axis of the light beam, while a disk with filters may be provided between the pierced member and the shutter, or between the device for generating and concentrating light and the pierced member, both being controlled by the computer.
In particular, according to the present invention, said circular filter may consist of a mirror photo-etched with a graphic screen according to a logarithmic angular function.
Moreover, said disk with filters may provide two neutral filters of a reciprocally double logarithmic density, in order to raise the light spot's excursion up to 50-60 dB.
In a preferred embodiment of the device according to the present invention, said pierced member, preferably comprised of a pierced disk, is arranged on a carriage, movable by means of a first stepper motor, and is endowed with a second stepper motor for selecting a hole.
Two structures are in addition arranged on said movable carriage, respectively endowed with a third and a fourth stepper motor, for orienting the pierced member with respect to the vertical axis and to the horizontal axis, passing through the center of the selected hole, respectively.
The third, the fourth and the second stepper motors are assembled on structures realized so that each one moves the preceding. The order of the sequence of the movements may, obviously, be changed.
Furthermore, mechanical reductions which increase the light spot resolution may be provided.
Each of the provided stepper motors is endowed with a recalibration stop.
The assembly of lenses and mirrors may be comprised of a first lens, arranged immediately after the pierced member, of two reflection mirrors, and of a second lens, the two lenses being arranged at a distance corresponding to the addition of their focal lengths.
As an alternative, the assembly of the lenses and mirrors may comprise a single lens, it also arranged immediately after the pierced member, two reflection mirrors and at least a double couple of movable mirrors at 45°, to compensate for the differences of optical path.
The projection head, endowed with a protective fairing and housed, preferably, in a high position with respect to the surface of projection, may comprise a horizontally orientable mirror, by means of a first DC motor and of a chain and gear system, and vertically, by means of a second DC motor and of a system with a steel wire and recovery springs, and two potentiometers which control the achievement of the desired position.
The device for generating and concentrating light will be preferably made up of an halogen lamp and of a condenser and of one or more lenses.
The shutter of the device according to the present invention, arranged downstream of the pierced element, endowed with a command logic and driven by a DC motor, provides a turnable blade, by action of said motor, and two fork light couplers which are covered or uncovered by the blade itself, the blade being realized asymmetrically or the two light couplers being arranged asymmetrically.
In particular, said DC motor is driven by a bridge of four transistors or by two complementary symmetry, power operational amplifiers.
The command logic provides three input signal and two signals returning from said light couplers.
BRIEF DESCRIPTION OF THE DRAWING
The present invention will be now described according to preferred embodiments thereof with particular reference to the figures of the enclosed drawings, in which:
FIG. 1 shows, schematically, the principle of the operation of a classic projector;
FIGS. 2a, 2b and 2c show schematically the principle of operation of a telescopic projector;
FIG. 3 shows schematically the principle of operation of a projector with a double mirror system;
FIG. 4 shows schematically the principle on the basis of which the device according to the present invention operates;
FIG. 5 shows schematically the principle of operation of the device according to the present invention, with a telescopic optics;
FIG. 6 is a plan view of the device according to the present invention;
FIG. 7 is a side view of the device according to the present invention;
FIG. 8 shows the projection head of the device according to the present invention;
FIG. 9 shows a second side view of the device according to the present invention;
FIG. 10 shows a particular graphic screen to be employed in the device according to the present invention;
FIG. 11 shows a block scheme of the circuit which controls the light shutter according to the present invention;
FIG. 12 shows an electric scheme of the circuit of FIG. 11, and
FIGS. 13 and 14 show the sequence of signals and the graph of the angular position of the light shutter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a classic projector. The condenser 1 projects the filament of the lamp 2 onto the lens 3. The subject 4 to be projected is at a distance D1 from the lens 3, which is conjugate to the distance D2 between the lens 3 and the projected image 5, that is to say such as:
1/D1+1/D2=1/F (1)
where F is the focal length of the lens 3. The magnification of the projected image 5 with respect to the subject is:
I=D2/D1 (2)
If D2 increases, it will be necessary to change D1 according to (1), in order to keep the image focussed, and the magnification increases according to (2).
In FIG. 2a, the lens 3 has been substituted with a telescope, i.e. with two lenses (6, 7) at a distance equal to the sum of the focal lengths F1+F2. If the subject 4 is close to the first lens 6, according to (1) the image 5 will be focussed at a distance: ##EQU1## and the magnification results to be:
I=D2/(F1+F2)=F2/F1 (4)
If, on the contrary, the subject 4 is in the focus of the first lens 6 (FIG. 2b) the rays between the two lenses turn out to be parallel and the second lens 7 focuses the image 5 at the distance: ##EQU2##
The linear interpolation between the two limits (3) and (5) gives:
D2=(F2+F2.sup.2 /F1)-(F2/F1).sup.2 *D1 (6)
that can be checked easily either for (3) and for (5). The magnification keeps however equal to:
I=F2/F1 (7)
A more rigorous proof of (6) and (7), easily obtained on the basis of the similitude of the triangles in FIG. 2c, is herein omitted.
In the case of FIG. 3 the whole optical distance between the lens of the projector 1 and the image 5 of the light spot, D2, is constant, being continuously compensated for by the mirrors 8, 9, 10, 11. The magnification ratio is given by the ratio D2/D1.
If the projection surface isn't at right angles with respect to the light beam emitted by the projector, it suffices to bend the subject in a direction parallel to the surface itself to compensate for the geometric proportions, as is demonstrated by the geometric proportions between the similar triangles in FIG. 4.
It is necessary to find a compromise between the magnification ratio and the focusing. Indeed, it is apparent from FIG. 4 that the point of the image closest to the lens 3, corresponds to that which is closest to the subject 4, and vice-versa, in opposition to what is requested from (1).
Employing also a projector with a telescopic optics, the image distortion may be compensated for by inclining the light spot disk, but in the opposite sense, as results from (6) and from FIG. 5.
However, it is seen from these figures that the horizontal movement of a point is magnified in the focused projected image, by a factor (F2/F1) 2 , whereas the lateral movement (magnification (7)) by a factor (F2/F1). Therefore it should be F2=F1 for a rigorous compensation.
Because on the contrary a higher ratio (e.g. 2:2) is useful to contain the range of the spot disk (1/4 of the range in the optical path D2), it will be demonstrated that for a spot small with respect to the focal distances, the depth of field is such that the two inclinations turn out to be, with a good approximation, equal and opposite, i.e.:
α=β (8)
Proof of (8):
Let AB, AE, β, F1, F2 be given from the graph in the FIG. 5; it will result:
CE=AE-AB* sin (β) (9)
BC=AB* cos (β) (10)
BC/CE=DI/DE (11)
BC/F1=DI/(DE+F1) (12)
By substituting for DI from (12) in (11), and developing with respect to DE:
DE=DI*CE/BC=(BC*(DE+F1)/F1)*(CE/BC)
F1*DE=CE*DE+F1*CE
DE=(F1*CE)/(F1-CE) (13)
By the proportion between the triangles IDE and BCE:
ID/BC=DE/CE
ID=(F1*CE)/(F1-CE)*BC/CE=(F1*BC)/(F1-CE) (14)
The two rays which come out from the virtual image I of the point B, which are represented in the figure, intersect the circle through P center L, in the two points N and M. The angle α is that for which the image of AB, projected onto a plane surface passing through LN or LM, keeps the length LP, and the closeness between N and M gives a measure of the field depth of the projection.
By similitude between the triangles NQG and GDI:
LG+AB*(F2/F1)* sin (α))/(AB*(F2/F1)* cos (α))=(F1+F2+DE)/ID
cos(α)=ID/(F1+F2+DE)*(sin (α)+(LG/AB*)(F1/F2) (15)
For light spots small with respect to the focal lengths it results (by substituting for 13, 14, 9, 10 in (15)): ##EQU3## and being, for (6), LG=(F2+F2 2 /F1)-(F2/F1) 2 *AE), the (8) has been proved.
Analogously, by the similitude between the triangles MRS and SGT, one obtains:
cos (α)=ID/F2*(sin(α)+(LG-F2)/AB*(F1/F2)) (16)
where the limit for AB→0 gives again the (8).
In practice, by solving (15) and (16) with the following values (in mm): F1=120; F2=240; AE=10 to 60; AB=5 (light spot V); β=0° to 20°, the values related in the following Table I for the angle α(β) and the defocusing dα are obtained in the worst case:
TABLE I______________________________________Beta d(Alpha) Alpha______________________________________ 1 .106 1.478 2 .303 2.827 3 .414 3.987 4 .500 5.097 5 .567 6.177 6 .621 7.239 7 .666 8.287 8 .703 9.326 9 .734 10.35710 .759 11.38211 .781 12.40212 .800 13.41813 .816 14.43214 .829 15.44215 .840 16.45016 .849 17.45617 .857 18.46018 .863 19.46219 .868 20.46320 .871 21.462______________________________________
By approximating such values with the (8) the size error is lower than the 9% about, the field depth allows a focusing better of the 5%. Both values fall below the 2% with the light spot III.
A device according to the present invention is represented in the FIGS. 6 to 9 in the embodiment with a telescopic projector.
The condenser 12 concentrates the light produced by a halogen lamp 13 onto the spot disk 14. The latter is movable in the space between the condenser 12 and pin 15 on a carriage 16 which is moved by a motor 17.
The movement of the carriage 16 is computed on the basis of the relation (6), by a computer, not represented, which computes the distance between lens 18 and the cupola 19 in a point-by-point way.
The image of the spot, selected by the motor 20, is projected by said lens 18, arranged at a distance equal to the sum of the focal lengths, and returned back to the mirrors 21, 22 and 23 into the dome 19.
Three stepper motors 20, 24 and 25, of small sizes, each being arranged on a structure that is moved by the other motor, are arranged on the carriage 16.
In particular, the motor 24 of SAG or horizontal inclination determines the rotation of the spot selected by the motor 20 in the horizontal sense, around the vertical axis passing through the spot, whereas the TILT or vertical inclination motor 25 rotates the spot in a vertical direction, while keeping the center thereof aligned with the axis of the light cone coming from the condenser 12.
The resolution in the orientation of the spot disk 14 is incresed by providing reduction wheels 26, 27 and 28. The two movements necessary to orient the disk are performed by motors 24 and 25 (see FIG. 6). Motor 24 is belted to wheel 28 which is in turn belted to move pin 15 in the horizontal direction as illustrated in FIG. 6. Motor 25 is belted to move wheel 26 which is belted to move wheel 27. By means of this transmission, the motor 20 is made rotatable on a vertical plane around the axis of the wheel 27. In other words, motor 24 moves motor 20 as well as the groups 25, 26 and 27 in horizontal direction, while motor 25 moves the motor 20 in vertical direction through the wheels 26 and 27. Said orientation is computed on the basis of (8), in the two senses, and of the incidence angle of the beam projected onto the dome, in a point-by-point way, taking into account the rotations impressed to the beam by the three mirrors 21, 22 and 23 also.
In the illustrated embodiment, the maximum provided rotation is of about 0° to 20° of SAG and -20° to +20° of TILT.
By means of a circular filter 29 and of the filters of the disk 30 the spot luminous intensity is controlled, in a range of about 20 dB. The filters of the disk 30 allow the color of the spot to be changed and the range thereof to be increased up to 50-60 dB by using two neutral filters of reciprocally double densities.
The circular filter 29 may be realized by employing a photographic emulsion or a metal deposited onto glass or polyester, though in this way it would malsupport the heat of the lamp, particularly in kinetic projections, and would be expensive.
In FIG. 10 a graphic screen, shaded according to a logarithmic angular function, employed to photoetch a mirror that embodies the filter 29 is represented. This solution is adoptable as the filter 29 is interposed between the condenser 12 and the spot disk 14.
The light that has not been transmitted is reflected, so avoiding the need for a filter against heat.
Its slope avoids light, independently of how it is out of focus, being returned just on lamp's 13 filament.
The shutter 31, whose structure and operation will be shown and disclosed in the following, is moved by means of a low cost direct current motor 32.
The projector head 33, see in particular FIG. 8, comprises a mirror 23 having such a shape, as to reflect the light beam into all the directions of the visual range and rotating horizontally by virtue of the motor 34, by chain and gears, and vertically, by virtue of the motor 35 and of a steel wire recovered by springs.
Two potentiometers 36 and 37 sense the orientation of the mirror 23, which potentiometers check the achieving of the angular position shown by the computer.
The two angles are computed as functions of the co-ordinates of the projection point into the dome 19, of the position of the mirror center and of the hole for inputting light.
A fairing 38 is also provided for, which protects the head of a patient from the contact with moving parts.
The projection head 33 preferably is housed in a high position on the dome 19 owing to the fact that the visual range is limited above to 60°-65°, which is a suitable angle for the hole for inputting light. If one had a greater angle, a larger mirror 23 would be necessary.
The shutter 31 is endowed with a blade 39 that may cover or uncover the light cone between the two lenses 15 and 18 dependently on being in a position in which fork light couplers 40 and 41 are both covered or both uncovered, because the blade 39 is realized in an asymmetrical way.
In case one wants the blade 39 to be realized in an asymmetrical way, it suffices to arrange the light couplers 40 and 41 asymmetrically.
In FIGS. 11 to 14 the shutter control circuit 31 and the logic of the operation thereof are shown.
The motor 32, that rotates the blade 39, is driven by a bridge of four resistors or by two complementary symmetry power operational amplifiers 42, 43, as depicted in FIG. 11.
A positive voltage (1) on the signal ORARIO and a negative one (0) on the signal ANTIORARIO are supposed to apply a clockwise couple, and viceversa, to the motor 32. A same voltage (1 or 0 applied to both) stops the motor.
The two signals, designated FA and FB, go high when the photoelectric cell 41 or 40 is uncovered and provide a "feedback" to keep the shutter 31 open if FA=FB=1 or closed if FA=FB=0.
The three signals designated with CHIU, uP and ACC, coming from the computer, control the operation of the shutter 31.
The logic is set forth in the following table II.
TABLE II__________________________________________________________________________ Inputs: Outputs:Situation: CHIU μP ACC FB FA ORARIO ANTIOR.__________________________________________________________________________Open shutter: quiescent 0 0 x 1 1 0(1) 0(1)conditioncounterclockwise 0 0 x 0 1 0 1feedbackClockwise feedback 0 0 x 1 0 1 0Closed shutter: 1 0 x 0 0 0(1) 0(1)quiescent condition:counterclockwise 1 0 x 1 0 0 1feedbackclockwise feedback 1 0 x 0 1 1 0(clockwise) Acceleration x 1 1 x x 1 0(clockwise) deceleration x 1 0 x x 0 1__________________________________________________________________________ 1 = HIGH logic level 0 = LOW logic level x = indifferently HIGH or LOW logic level () = alternative logic level, on both outputs
When μP=0 and CHIU=0, the "feedback" of the two local signals FA and FB keeps the shutter 31 open: an unbalance of the blade 39 to cover the photoelectric cell 40 and 41 produces a couple on the motor 32 which returns the blade 39 itself into an open position.
Analogously, when μP=0 and CHIU=1, the "feedback" of the two local signals FA and FB keeps the shutter 31 closed.
When μP=1, the automatic control of the photoelectric cells 40 and 41 is cut off, and the computer may accelerate or decelerate the motor (as a reference, in the clockwise sense), with the signal ACC being =1 or =0 respectively.
The schematic in FIG. 12 shows an embodiment of the drive circuit with only two integrated circuits. The resistor 21 allows some electric current to be saved during static phases.
A typical signal sequence, for a static or a kinetic projection, is illustrated in FIG. 13, together with a graph of the angular position of the shutter 31. 5 phases are provided: the first acceleration and deceleration (of a fixed time interval), a pause (of an adjustable time interval), the second acceleration and deceleration (of a fixed time interval).
The light beam is crossed at the maximum speed, and opening times of 100 ms with beam transition of 5-10 ms may be easily obtained.
Shorter times (up to about 1/4 of the said time lengths) may be achieved by not stopping the motor 32, up to the boundary condition of two phases only (FIG. 14).
The shutter 31 may be utilized to modulate light at a prefixed frequency, by controlling the "duty-cycle" of two periodic acceleration-deceleration phases. The "feedback" for the rotation frequency may come to the computer from FA or FB indifferently. This application is particularly suitable in the flicker perimetry.
The present invention has been disclosed with specific reference to some preferred embodiments thereof, but it is to be understood that variations and/or changes may be made by those who are skilled in the art, without so departing from the scope of the enclosed claims. | A device for projecting light spots onto a surface, comprising a device for generating and concentrating light, a pierced member which is movable before said device and endowed with means for selecting the hole to be aligned with the light, an assembly of lenses and mirrors and a projection head for projecting light onto a surface, and a shutter member, which controls the projection of the beam itself, in which device means for orienting said pierced member around the vertical axis passing through the center of the selected hole and means for orienting the same pierced member around the horizontal axis passing through the center of the selected hole are provided; the orientation and position of the pierced member, as well as the selection of the hole and of the orientation of the projection head, being achieved by a computer. | Briefly describe the main invention outlined in the provided context. | [
"DISCLOSURE OF THE INVENTION The present invention relates to a device for projecting light spots onto a surface.",
"More particularly, the present invention relates to a device of said type, which allows light spots having a shape and size which are constant on a plane or curved surface to be projected, at a varying distance and slope.",
"The projection of light spots onto surfaces is particularly, though not exclusively, applied in apparatuses for measuring human visual range, in particular in the apparatuses called "perimeters".",
"In these instruments the projection surface is a white hemispherical dome, at the center of which the patient's eye is to be placed.",
"Consequently, the system for projecting the spots onto the hemispherical dome turns out to be off centre.",
"As is well known, an accurate measurement of the visual range is of a great importance in ophthalmology, in the diagnosis and in the "follow-up"",
"of several diseases, particularly in glaucoma.",
"Visual range is the visibility threshold in the various spatial directions with respect to the stared point.",
"During the examination of the visual range, a patient has to fix his eyes on a point at the center of a white hemispherical dome upon which luminous stimuli, or light spots, are projected from the periphery to the center of the hemispherical dome.",
"In the "kinetic"",
"perimetry, the patient must press a button as soon as he sees a stimulus which moves from the periphery to the center of the visual range, whereas in the "static"",
"perimetry static stimuli of a higher and higher brightness are projected until the patient presses the button.",
"The combination of the "visual points"",
"on the whole range makes up a map of the visual range.",
"In Goldmann's perimeter, realized in 1945, which is still referred to as a standard, the hemispherical dome has a 33 cm radius and light spots of 0.01 to 1000 Apostilb, having surfaces of 1/16, 1/4, 1, 4, 16, 64 mm 2 (spot: O, I, II, III, IV and V) are projected onto the ground, which is uniformly lit at 31.5 Apostilb.",
"An arm pivoted on the vertical axis of the hemispherical dome, which turns behind the patient's head, brings a lens so inclined and orientable as to be able to project the light spot onto any point in the hemispherical dome, while keeping at the same distance and slope with respect to its surface.",
"As a consequence the light spot results always to be elliptic, but of a constant shape and size, and the projector does not require a continuous focusing.",
"Computer-controlled automatic perimeters have been realized, based upon the same principle of Goldmann's one, in the subsequent developments of these apparatuses.",
"The main problems found in their realization are pertinent to the driving, due to encumbrance, and to the displacement of the projection mechanism from the right to the left side.",
"Some examples as regards the above are the perimeter PERIKON Optikon, and patents U.S. Pat. No. 3,414,348, U.S. Pat. No. 4,145,123, U.S. Pat. No. 4,260,227 and U.S. Pat. No. 3,664,732.",
"Subsequently, in many perimeters, the projection criterion of Goldmann has been abandoned for the lighter systems, which comprise a movable mirror housed in the hemispherical dome out of the visual range, generally above the head of the patient, as for instance in the patents EU 0,242,723, U.S. Pat. No. 4,561,738 and in the perimeters Octopus and Squid.",
"Owing, however, to the different distance between this mirror and the various points of the dome, and to the oblique incidence of the projected ray onto its surface, the light spots which are obtained with these devices haven't a constant shape.",
"Some perimeters in which a larger dome has been adopted, out of Goldmann's standard, have been realized, such as the perimeters Octopus Interzeag, in order to reduce such shortcoming to a minimum.",
"Still in other perimeters, as for instance the perimeter Bausch &",
"Lomb FIELDMASTER 5000, fewer mirrors to put away the projector have been used, and the orientable mirror has been placed almost in contact with the forehead of the patient, in order to reduce the relative differences of the path of the beam.",
"The problem has been however so added of a lower light yield of the projector and therefore of the necessity for employing more powerful lamps, fans, etc.",
"In such perimeters the light beam passes through holes of not a negligible size, located in the visual range, to contain the size of the orientable mirror.",
"The more recent perimeters are generally magnifycation-and spot-focusing-compensated.",
"In a few instances (U.S. Pat. No. 4,561,738, Humoured) the well-known property of a telescope of having a magnification ratio between the object and the image which is equal to the ratio between the two lenses and is independent of distance is exploited, by arranging the object-light spot in the conjugate position with respect to that of the projected image.",
"In another patent (Patent EU 0,242,723, Techna Vision) a double couple of movable mirrors at 45° is interposed, which compensates for the differences of the optical path, keeping at the same time either magnification and focusing.",
"Either system, however, does not take into account the fact that the light spot on an oblique surface turns out to be distorted.",
"Because the projectors of the perimeters realized according to the latest patents have a projection head which in definitive is larger and more displaced off the center than in the preceding perimeters, in a few points the light spot results to be much more distorted than in other points, with a change in the surface of the 20% and more.",
"Moreover, the particular realization of most projectors described heretofore limits the application thereof to the only static or kinetic perimetry, and such projectors often result to be slow or noisy, with the prejudice of the foreseeability of the stimulus, which makes the test's result less reliable.",
"Finally, the projectors of the automatic perimeters heretofore realized do not provide any system that allows the intermittency of the light to be regulated, to measure the critical frequency of fusion of the patient in the various points of the visual range.",
"Such a type of test (flicker perimetry), though it is ascertained that it would furnish a useful information for the diagnosis of glaucoma, has always relied upon instruments that do not guarantee standard or reproducible test conditions.",
"In view of the above-mentioned problems, the Applicant suggests to realize a device for projecting light spots which is able to obviate all the mentioned drawbacks.",
"The primary object of the present invention is to provide a device of said type which is able to project circular light spots of constant shape and size, by virtue of being endowed of mechanisms compensating for the shape and the size of the light spot themselves projected in the dome indpendently of the the distance and of the inclination of the latter with respect to the projector itself.",
"It is still an object of the present invention to provide a device which is adoptable on perimeters realized either with a telescopic projection system, or with a double couple of movable mirrors.",
"A further object of the present invention is to realize a device that allows either the kinetic and the static perimetry to be carried out.",
"Another object of the present invention is to obtain a device endowed with a system for regulating the intermittency, to measure the critical frequency of fusion of the patient in the various points of the visual range.",
"It is therefore a specific object of the present invention a device for projecting light spots onto a surface, which device comprises a device for producing and concentrating light, a pierced member, which is movable before said device and is endowed with means for selecting a hole to be aligned with the light, an assembly of lenses and mirrors and a projection head for projecting the light onto a surface, and a shutter member, which regulates the projection of the light beam itself, in which device means for orienting said pierced member around the vertical axis passing through the center of the selected hole and means for orienting the same pierced member around the horizontal axis passing through the center of the selected hole are provided;",
"the orientation and the position of the pierced member, as well as the selection of the hole and of the orientation of the projection head being obtained by a computer.",
"Between the device for generating and concentrating the light and the pierced member a circular filter may be provided, which is preferably inclined with respect to the axis of the light beam, while a disk with filters may be provided between the pierced member and the shutter, or between the device for generating and concentrating light and the pierced member, both being controlled by the computer.",
"In particular, according to the present invention, said circular filter may consist of a mirror photo-etched with a graphic screen according to a logarithmic angular function.",
"Moreover, said disk with filters may provide two neutral filters of a reciprocally double logarithmic density, in order to raise the light spot's excursion up to 50-60 dB.",
"In a preferred embodiment of the device according to the present invention, said pierced member, preferably comprised of a pierced disk, is arranged on a carriage, movable by means of a first stepper motor, and is endowed with a second stepper motor for selecting a hole.",
"Two structures are in addition arranged on said movable carriage, respectively endowed with a third and a fourth stepper motor, for orienting the pierced member with respect to the vertical axis and to the horizontal axis, passing through the center of the selected hole, respectively.",
"The third, the fourth and the second stepper motors are assembled on structures realized so that each one moves the preceding.",
"The order of the sequence of the movements may, obviously, be changed.",
"Furthermore, mechanical reductions which increase the light spot resolution may be provided.",
"Each of the provided stepper motors is endowed with a recalibration stop.",
"The assembly of lenses and mirrors may be comprised of a first lens, arranged immediately after the pierced member, of two reflection mirrors, and of a second lens, the two lenses being arranged at a distance corresponding to the addition of their focal lengths.",
"As an alternative, the assembly of the lenses and mirrors may comprise a single lens, it also arranged immediately after the pierced member, two reflection mirrors and at least a double couple of movable mirrors at 45°, to compensate for the differences of optical path.",
"The projection head, endowed with a protective fairing and housed, preferably, in a high position with respect to the surface of projection, may comprise a horizontally orientable mirror, by means of a first DC motor and of a chain and gear system, and vertically, by means of a second DC motor and of a system with a steel wire and recovery springs, and two potentiometers which control the achievement of the desired position.",
"The device for generating and concentrating light will be preferably made up of an halogen lamp and of a condenser and of one or more lenses.",
"The shutter of the device according to the present invention, arranged downstream of the pierced element, endowed with a command logic and driven by a DC motor, provides a turnable blade, by action of said motor, and two fork light couplers which are covered or uncovered by the blade itself, the blade being realized asymmetrically or the two light couplers being arranged asymmetrically.",
"In particular, said DC motor is driven by a bridge of four transistors or by two complementary symmetry, power operational amplifiers.",
"The command logic provides three input signal and two signals returning from said light couplers.",
"BRIEF DESCRIPTION OF THE DRAWING The present invention will be now described according to preferred embodiments thereof with particular reference to the figures of the enclosed drawings, in which: FIG. 1 shows, schematically, the principle of the operation of a classic projector;",
"FIGS. 2a, 2b and 2c show schematically the principle of operation of a telescopic projector;",
"FIG. 3 shows schematically the principle of operation of a projector with a double mirror system;",
"FIG. 4 shows schematically the principle on the basis of which the device according to the present invention operates;",
"FIG. 5 shows schematically the principle of operation of the device according to the present invention, with a telescopic optics;",
"FIG. 6 is a plan view of the device according to the present invention;",
"FIG. 7 is a side view of the device according to the present invention;",
"FIG. 8 shows the projection head of the device according to the present invention;",
"FIG. 9 shows a second side view of the device according to the present invention;",
"FIG. 10 shows a particular graphic screen to be employed in the device according to the present invention;",
"FIG. 11 shows a block scheme of the circuit which controls the light shutter according to the present invention;",
"FIG. 12 shows an electric scheme of the circuit of FIG. 11, and FIGS. 13 and 14 show the sequence of signals and the graph of the angular position of the light shutter.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a classic projector.",
"The condenser 1 projects the filament of the lamp 2 onto the lens 3.",
"The subject 4 to be projected is at a distance D1 from the lens 3, which is conjugate to the distance D2 between the lens 3 and the projected image 5, that is to say such as: 1/D1+1/D2=1/F (1) where F is the focal length of the lens 3.",
"The magnification of the projected image 5 with respect to the subject is: I=D2/D1 (2) If D2 increases, it will be necessary to change D1 according to (1), in order to keep the image focussed, and the magnification increases according to (2).",
"In FIG. 2a, the lens 3 has been substituted with a telescope, i.e. with two lenses (6, 7) at a distance equal to the sum of the focal lengths F1+F2.",
"If the subject 4 is close to the first lens 6, according to (1) the image 5 will be focussed at a distance: ##EQU1## and the magnification results to be: I=D2/(F1+F2)=F2/F1 (4) If, on the contrary, the subject 4 is in the focus of the first lens 6 (FIG.",
"2b) the rays between the two lenses turn out to be parallel and the second lens 7 focuses the image 5 at the distance: ##EQU2## The linear interpolation between the two limits (3) and (5) gives: D2=(F2+F2.",
"sup[.",
"].2 /F1)-(F2/F1).",
"sup[.",
"].2 *D1 (6) that can be checked easily either for (3) and for (5).",
"The magnification keeps however equal to: I=F2/F1 (7) A more rigorous proof of (6) and (7), easily obtained on the basis of the similitude of the triangles in FIG. 2c, is herein omitted.",
"In the case of FIG. 3 the whole optical distance between the lens of the projector 1 and the image 5 of the light spot, D2, is constant, being continuously compensated for by the mirrors 8, 9, 10, 11.",
"The magnification ratio is given by the ratio D2/D1.",
"If the projection surface isn't at right angles with respect to the light beam emitted by the projector, it suffices to bend the subject in a direction parallel to the surface itself to compensate for the geometric proportions, as is demonstrated by the geometric proportions between the similar triangles in FIG. 4. It is necessary to find a compromise between the magnification ratio and the focusing.",
"Indeed, it is apparent from FIG. 4 that the point of the image closest to the lens 3, corresponds to that which is closest to the subject 4, and vice-versa, in opposition to what is requested from (1).",
"Employing also a projector with a telescopic optics, the image distortion may be compensated for by inclining the light spot disk, but in the opposite sense, as results from (6) and from FIG. 5. However, it is seen from these figures that the horizontal movement of a point is magnified in the focused projected image, by a factor (F2/F1) 2 , whereas the lateral movement (magnification (7)) by a factor (F2/F1).",
"Therefore it should be F2=F1 for a rigorous compensation.",
"Because on the contrary a higher ratio (e.g. 2:2) is useful to contain the range of the spot disk (1/4 of the range in the optical path D2), it will be demonstrated that for a spot small with respect to the focal distances, the depth of field is such that the two inclinations turn out to be, with a good approximation, equal and opposite, i.e.: α=β (8) Proof of (8): Let AB, AE, β, F1, F2 be given from the graph in the FIG. 5;",
"it will result: CE=AE-AB* sin (β) (9) BC=AB* cos (β) (10) BC/CE=DI/DE (11) BC/F1=DI/(DE+F1) (12) By substituting for DI from (12) in (11), and developing with respect to DE: DE=DI*CE/BC=(BC*(DE+F1)/F1)*(CE/BC) F1*DE=CE*DE+F1*CE DE=(F1*CE)/(F1-CE) (13) By the proportion between the triangles IDE and BCE: ID/BC=DE/CE ID=(F1*CE)/(F1-CE)*BC/CE=(F1*BC)/(F1-CE) (14) The two rays which come out from the virtual image I of the point B, which are represented in the figure, intersect the circle through P center L, in the two points N and M. The angle α is that for which the image of AB, projected onto a plane surface passing through LN or LM, keeps the length LP, and the closeness between N and M gives a measure of the field depth of the projection.",
"By similitude between the triangles NQG and GDI: LG+AB*(F2/F1)* sin (α))/(AB*(F2/F1)* cos (α))=(F1+F2+DE)/ID cos(α)=ID/(F1+F2+DE)*(sin (α)+(LG/AB*)(F1/F2) (15) For light spots small with respect to the focal lengths it results (by substituting for 13, 14, 9, 10 in (15)): ##EQU3## and being, for (6), LG=(F2+F2 2 /F1)-(F2/F1) 2 *AE), the (8) has been proved.",
"Analogously, by the similitude between the triangles MRS and SGT, one obtains: cos (α)=ID/F2*(sin(α)+(LG-F2)/AB*(F1/F2)) (16) where the limit for AB→0 gives again the (8).",
"In practice, by solving (15) and (16) with the following values (in mm): F1=120;",
"F2=240;",
"AE=10 to 60;",
"AB=5 (light spot V);",
"β=0° to 20°, the values related in the following Table I for the angle α(β) and the defocusing dα are obtained in the worst case: TABLE I______________________________________Beta d(Alpha) Alpha______________________________________ 1 [.",
"].106 1.478 2 [.",
"].303 2.827 3 [.",
"].414 3.987 4 [.",
"].500 5.097 5 [.",
"].567 6.177 6 [.",
"].621 7.239 7 [.",
"].666 8.287 8 [.",
"].703 9.326 9 [.",
"].734 10.35710 [.",
"].759 11.38211 [.",
"].781 12.40212 [.",
"].800 13.41813 [.",
"].816 14.43214 [.",
"].829 15.44215 [.",
"].840 16.45016 [.",
"].849 17.45617 [.",
"].857 18.46018 [.",
"].863 19.46219 [.",
"].868 20.46320 [.",
"].871 21.462______________________________________ By approximating such values with the (8) the size error is lower than the 9% about, the field depth allows a focusing better of the 5%.",
"Both values fall below the 2% with the light spot III.",
"A device according to the present invention is represented in the FIGS. 6 to 9 in the embodiment with a telescopic projector.",
"The condenser 12 concentrates the light produced by a halogen lamp 13 onto the spot disk 14.",
"The latter is movable in the space between the condenser 12 and pin 15 on a carriage 16 which is moved by a motor 17.",
"The movement of the carriage 16 is computed on the basis of the relation (6), by a computer, not represented, which computes the distance between lens 18 and the cupola 19 in a point-by-point way.",
"The image of the spot, selected by the motor 20, is projected by said lens 18, arranged at a distance equal to the sum of the focal lengths, and returned back to the mirrors 21, 22 and 23 into the dome 19.",
"Three stepper motors 20, 24 and 25, of small sizes, each being arranged on a structure that is moved by the other motor, are arranged on the carriage 16.",
"In particular, the motor 24 of SAG or horizontal inclination determines the rotation of the spot selected by the motor 20 in the horizontal sense, around the vertical axis passing through the spot, whereas the TILT or vertical inclination motor 25 rotates the spot in a vertical direction, while keeping the center thereof aligned with the axis of the light cone coming from the condenser 12.",
"The resolution in the orientation of the spot disk 14 is incresed by providing reduction wheels 26, 27 and 28.",
"The two movements necessary to orient the disk are performed by motors 24 and 25 (see FIG. 6).",
"Motor 24 is belted to wheel 28 which is in turn belted to move pin 15 in the horizontal direction as illustrated in FIG. 6. Motor 25 is belted to move wheel 26 which is belted to move wheel 27.",
"By means of this transmission, the motor 20 is made rotatable on a vertical plane around the axis of the wheel 27.",
"In other words, motor 24 moves motor 20 as well as the groups 25, 26 and 27 in horizontal direction, while motor 25 moves the motor 20 in vertical direction through the wheels 26 and 27.",
"Said orientation is computed on the basis of (8), in the two senses, and of the incidence angle of the beam projected onto the dome, in a point-by-point way, taking into account the rotations impressed to the beam by the three mirrors 21, 22 and 23 also.",
"In the illustrated embodiment, the maximum provided rotation is of about 0° to 20° of SAG and -20° to +20° of TILT.",
"By means of a circular filter 29 and of the filters of the disk 30 the spot luminous intensity is controlled, in a range of about 20 dB.",
"The filters of the disk 30 allow the color of the spot to be changed and the range thereof to be increased up to 50-60 dB by using two neutral filters of reciprocally double densities.",
"The circular filter 29 may be realized by employing a photographic emulsion or a metal deposited onto glass or polyester, though in this way it would malsupport the heat of the lamp, particularly in kinetic projections, and would be expensive.",
"In FIG. 10 a graphic screen, shaded according to a logarithmic angular function, employed to photoetch a mirror that embodies the filter 29 is represented.",
"This solution is adoptable as the filter 29 is interposed between the condenser 12 and the spot disk 14.",
"The light that has not been transmitted is reflected, so avoiding the need for a filter against heat.",
"Its slope avoids light, independently of how it is out of focus, being returned just on lamp's 13 filament.",
"The shutter 31, whose structure and operation will be shown and disclosed in the following, is moved by means of a low cost direct current motor 32.",
"The projector head 33, see in particular FIG. 8, comprises a mirror 23 having such a shape, as to reflect the light beam into all the directions of the visual range and rotating horizontally by virtue of the motor 34, by chain and gears, and vertically, by virtue of the motor 35 and of a steel wire recovered by springs.",
"Two potentiometers 36 and 37 sense the orientation of the mirror 23, which potentiometers check the achieving of the angular position shown by the computer.",
"The two angles are computed as functions of the co-ordinates of the projection point into the dome 19, of the position of the mirror center and of the hole for inputting light.",
"A fairing 38 is also provided for, which protects the head of a patient from the contact with moving parts.",
"The projection head 33 preferably is housed in a high position on the dome 19 owing to the fact that the visual range is limited above to 60°-65°, which is a suitable angle for the hole for inputting light.",
"If one had a greater angle, a larger mirror 23 would be necessary.",
"The shutter 31 is endowed with a blade 39 that may cover or uncover the light cone between the two lenses 15 and 18 dependently on being in a position in which fork light couplers 40 and 41 are both covered or both uncovered, because the blade 39 is realized in an asymmetrical way.",
"In case one wants the blade 39 to be realized in an asymmetrical way, it suffices to arrange the light couplers 40 and 41 asymmetrically.",
"In FIGS. 11 to 14 the shutter control circuit 31 and the logic of the operation thereof are shown.",
"The motor 32, that rotates the blade 39, is driven by a bridge of four resistors or by two complementary symmetry power operational amplifiers 42, 43, as depicted in FIG. 11.",
"A positive voltage (1) on the signal ORARIO and a negative one (0) on the signal ANTIORARIO are supposed to apply a clockwise couple, and viceversa, to the motor 32.",
"A same voltage (1 or 0 applied to both) stops the motor.",
"The two signals, designated FA and FB, go high when the photoelectric cell 41 or 40 is uncovered and provide a "feedback"",
"to keep the shutter 31 open if FA=FB=1 or closed if FA=FB=0.",
"The three signals designated with CHIU, uP and ACC, coming from the computer, control the operation of the shutter 31.",
"The logic is set forth in the following table II.",
"TABLE II__________________________________________________________________________ Inputs: Outputs:Situation: CHIU μP ACC FB FA ORARIO ANTIOR.",
"__________________________________________________________________________Open shutter: quiescent 0 0 x 1 1 0(1) 0(1)conditioncounterclockwise 0 0 x 0 1 0 1feedbackClockwise feedback 0 0 x 1 0 1 0Closed shutter: 1 0 x 0 0 0(1) 0(1)quiescent condition:counterclockwise 1 0 x 1 0 0 1feedbackclockwise feedback 1 0 x 0 1 1 0(clockwise) Acceleration x 1 1 x x 1 0(clockwise) deceleration x 1 0 x x 0 1__________________________________________________________________________ 1 = HIGH logic level 0 = LOW logic level x = indifferently HIGH or LOW logic level = alternative logic level, on both outputs When μP=0 and CHIU=0, the "feedback"",
"of the two local signals FA and FB keeps the shutter 31 open: an unbalance of the blade 39 to cover the photoelectric cell 40 and 41 produces a couple on the motor 32 which returns the blade 39 itself into an open position.",
"Analogously, when μP=0 and CHIU=1, the "feedback"",
"of the two local signals FA and FB keeps the shutter 31 closed.",
"When μP=1, the automatic control of the photoelectric cells 40 and 41 is cut off, and the computer may accelerate or decelerate the motor (as a reference, in the clockwise sense), with the signal ACC being =1 or =0 respectively.",
"The schematic in FIG. 12 shows an embodiment of the drive circuit with only two integrated circuits.",
"The resistor 21 allows some electric current to be saved during static phases.",
"A typical signal sequence, for a static or a kinetic projection, is illustrated in FIG. 13, together with a graph of the angular position of the shutter 31.",
"5 phases are provided: the first acceleration and deceleration (of a fixed time interval), a pause (of an adjustable time interval), the second acceleration and deceleration (of a fixed time interval).",
"The light beam is crossed at the maximum speed, and opening times of 100 ms with beam transition of 5-10 ms may be easily obtained.",
"Shorter times (up to about 1/4 of the said time lengths) may be achieved by not stopping the motor 32, up to the boundary condition of two phases only (FIG.",
"14).",
"The shutter 31 may be utilized to modulate light at a prefixed frequency, by controlling the "duty-cycle"",
"of two periodic acceleration-deceleration phases.",
"The "feedback"",
"for the rotation frequency may come to the computer from FA or FB indifferently.",
"This application is particularly suitable in the flicker perimetry.",
"The present invention has been disclosed with specific reference to some preferred embodiments thereof, but it is to be understood that variations and/or changes may be made by those who are skilled in the art, without so departing from the scope of the enclosed claims."
] |
BACKGROUND
[0001] The invention relates to a computer system with multiple CPU configurations, and more particularly, to methods and apparatuses providing multiple CPU configurations to a computer system.
[0002] FIG. 1A is a block diagram of a conventional computer motherboard. The motherboard comprises a CPU area 11 and a system core logic area 12 . The CPU area 11 comprises a CPU 111 and a CPU control circuit 112 controlling the power supply and thermal solution for the CPU. The CPU area 11 connects to the system core logic area 12 via bus 121 .
[0003] The system core logic area 12 comprises a system chipset 120 , a system memory 132 coupled thereto via system memory bus 122 , a system input/output controller 133 coupled thereto via system input/output bus 123 and a system control circuit 134 coupled thereto via system control bus 124 .
[0004] Single or multiple system memory buses 122 on the motherboard connect to one or more memory devices such as a SDRAM bus and a DDR SDRAM bus. A Dual Channel system memory bus utilizes two independent memory controllers for improved system performance.
[0005] The system input/output controller 133 controls interfaces with external devices. One or more system input/output buses each connect to one or more system input/output devices and may be a PCI bus and/or an ISA bus. Input/output connectors 135 connected to different interface buses 125 respectively connect to external devices/cables thereby.
[0006] System control circuit 134 contains circuits controlling the power and thermal solutions for the computer system.
[0007] FIG. 1B is another block diagram of a computer motherboard. The motherboard comprises a CPU area 11 and a system core logic area 12 . The difference between this system and that shown in FIG. 1A is system memory 113 connecting to the CPU 111 instead of the system core logic chipset 120 , allowing the CPU to directly access system memory for high speed computing without accessing system logic chipset 120 . All other devices access system memory through system logic chipset 120 , which directs the requests to CPU 111 .
[0008] Conventional motherboards comprise core logic chipsets and CPU configurations that cannot be changed. Installation of a CPU not compatible with the initial CPU socket requires replacement of motherboard, and possibly related devices, representing considerable inconvenience and cost.
SUMMARY
[0009] A method and device providing multiple CPU configuration of a computer system are disclosed. A motherboard supporting the device is also provided. When a module with a first CPU is not connected to the motherboard via an expansion connector, a second CPU is connected with the system logic unit, and the expansion connector is disconnected from the system logic unit. When the module is connected to the expansion connector, the second CPU is disconnected from the system logic unit, and the system logic unit is electrically connected with the expansion connector.
[0010] Additional features and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The features and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
[0011] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings, incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the features, advantages, and principles of the invention.
[0013] FIGS. 1A and 1B are block diagrams of conventional computer systems.
[0014] FIG. 2 is a block diagram of a motherboard according to an embodiment of the invention.
[0015] FIG. 3 is a block diagram of a module applied with the motherboard of FIG. 2 .
[0016] FIG. 4 is a block diagram of a motherboard according to another embodiment of the invention.
[0017] FIG. 5 is a block diagram of a module applied with the motherboard of FIG. 4 .
DETAILED DESCRIPTION
[0018] The invention is adaptive to change the CPU configuration in a computer system. Various core logic chipsets support more than one type of CPU. Bus signals between the system core logic chipset and an initial CPU, switched to connect with another upgraded CPU, allow an existing motherboard to accommodate different types of CPUs. A module is provided to carry the second CPU for upgrading. An expansion connector on the motherboard connects the module. When the module connects to the expansion connector, the core logic chipset is disconnected from the initial CPU interface, and electrically connected to the expansion connector, to communicate with the upgraded CPU carried by the module. A bus switching device selectively switches the connection to the core logic chipset between the initial CPU interface and the expansion connector.
[0019] The system memory may connect to the CPU rather than the core logic chipset. The module must comprise system memory devices if the upgraded CPU on the module controls the memory interface.
[0020] The bus switching device can be a set of jumpers set to connect the system core logic chipset to the initial CPU or to the expansion connector, or a bus switching IC chip receiving a control signal generated in the motherboard, which sets the signal to a first state to control the bus switching IC to connect the core logic chipset with the initial CPU when the expansion connector is empty, and a second state to control the bus switching IC to connect the core logic chipset with the expansion connector when the expansion connector connects to the module. The bus switching device disconnects the unused device and its related bus routing from the active bus, improving the signal integrity by preventing the loading and signal reflection caused by the unused device and the is bus routing.
[0021] FIG. 2 is a block diagram of a motherboard according to an embodiment of the invention. The motherboard comprises a CPU area 21 , a system logic area 22 , a bus switching device 23 and an expansion connector 24 .
[0022] CPU area 21 comprises a CPU 211 , assembled initial or connecting to the motherboard through an initial CPU socket. The CPU area 21 further comprises other devices connect directly to the second CPU 211 but the system logic area 22 . For example, if CPU 211 connects directly to a system memory, the CPU area 21 comprises system memory (not shown). The CPU area 21 further comprises control circuits (not shown) controlling the power supply and thermal solutions of the CPU area 21 .
[0023] System logic area 22 connects to bus switching device 23 via bus 221 . The bus switching device 23 connects to CPU area 21 via bus 2211 and the expansion connector 24 via the bus 2212 . The bus switching device 23 electrically connects the signals of the bus 221 to the signals of bus 2211 if the expansion connector 24 is not connected to any device. The system logic area 22 connects to the second CPU area 21 and forms a complete system structure that boots and computes normally.
[0024] FIG. 3 shows a block diagram of a module applicable with the motherboard of FIG. 2 . The module 31 comprises a CPU area 310 and a signal connector 312 connecting with the expansion connector 24 . CPU 311 can be assembled initial or connect to the CPU area 310 through an initial CPU socket. The module 31 further comprises other devices which connect directly to the first CPU 311 . For example, if the first CPU 311 connects directly to the system memory, the module 31 comprises system memory (not shown).
[0025] The bus switching device 23 electrically connects the signals of the bus 221 with the signals of the bus 2212 if the expansion connector 24 is connected to the module 31 . The system logic area 22 connects to the first CPU area 310 and forms a complete system structure that boots and computes normally.
[0026] FIG. 4 is a block diagram of a motherboard according to another embodiment of the invention. The motherboard comprises a CPU area 41 , a system logic area 42 , a bus switching device 44 and an expansion connector 43 .
[0027] The CPU area 41 comprises a CPU 411 (AMD Athelon-64 754 pin), assembled initial or connecting to the motherboard through an initial CPU socket.
[0028] Because the AMD Athelon-64 754 pin CPU comprises a single channel DDR SDRAM interface, the CPU area 41 further comprises two DDR SDRAM sockets 412 to connect system memory devices. The CPU area 41 further comprises CPU control circuits 413 controlling the power supply and thermal solutions for the second CPU area 41 .
[0029] The system logic area 42 comprises the system core logic unit 420 (SIS 760 Northbridge and SIS964 Southbridge system core logic chipset). The system logic area 42 further comprises all other devices not directly connected to the CPU area 41 .
[0030] The system logic area 42 connects to the bus switching device 43 via the bus 421 . The bus switching device 44 connects to the CPU area 41 via the bus 4211 and to the expansion connector 43 via the bus 4212 . The bus switching device 44 electrically connects the signals of the bus 421 with the signals of the bus 4211 if the expansion connector 43 is not connected to any device. The system logic area 42 connects to the CPU area 41 and forms a complete system structure that boots and computes normally.
[0031] FIG. 5 is a block diagram of a module applicable with the motherboard of t FIG. 4 . The module 51 comprises a CPU 511 (AMD Athelon-64 939 pin CPU) and a signal connector 516 connecting with the expansion connector 43 , assembled initial or connecting to the module through an initial CPU socket.
[0032] The module 51 further comprises other devices directly connected to the CPU but not the system logic area 42 . Because the AMD Athelon-64 939 pin CPU comprises dual channel DDR SDRAM interfaces, the module 51 further comprises four DDR SDRAM sockets ( 5121 , 5122 ) to connect system memory devices. The module 51 further comprises CPU control circuits 53 controlling power supply and thermal solutions of the module 51 .
[0033] The bus switching device 44 electrically connects the signals of the bus 421 with the signals of the bus 4212 if the expansion connector 43 is connected to the module 51 . The system logic area 42 connects to the module 51 and forms a complete system structure that could be boot up and compute normally.
[0034] The invention enables replacement of CPUs in a computer system, reducing cost and inconvenience.
[0035] While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. Those who are skilled in this technology can still make various alterations and modifications without departing from the scope and spirit of this invention. Therefore, the scope of the present invention shall be defined and protected by the following claims and their equivalents. | A method and device providing multiple CPU configuration of a computer system are disclosed. A motherboard supporting the device is also provided. When a module with a first CPU is not connected to the motherboard via an expansion connector, a second CPU is connected with the system logic unit, and the expansion connector is disconnected from the system logic unit. When the module is connected to the expansion connector, the second CPU is disconnected from the system logic unit, and the system logic unit is electrically connected with the expansion connector. | Condense the core contents of the given document. | [
"BACKGROUND [0001] The invention relates to a computer system with multiple CPU configurations, and more particularly, to methods and apparatuses providing multiple CPU configurations to a computer system.",
"[0002] FIG. 1A is a block diagram of a conventional computer motherboard.",
"The motherboard comprises a CPU area 11 and a system core logic area 12 .",
"The CPU area 11 comprises a CPU 111 and a CPU control circuit 112 controlling the power supply and thermal solution for the CPU.",
"The CPU area 11 connects to the system core logic area 12 via bus 121 .",
"[0003] The system core logic area 12 comprises a system chipset 120 , a system memory 132 coupled thereto via system memory bus 122 , a system input/output controller 133 coupled thereto via system input/output bus 123 and a system control circuit 134 coupled thereto via system control bus 124 .",
"[0004] Single or multiple system memory buses 122 on the motherboard connect to one or more memory devices such as a SDRAM bus and a DDR SDRAM bus.",
"A Dual Channel system memory bus utilizes two independent memory controllers for improved system performance.",
"[0005] The system input/output controller 133 controls interfaces with external devices.",
"One or more system input/output buses each connect to one or more system input/output devices and may be a PCI bus and/or an ISA bus.",
"Input/output connectors 135 connected to different interface buses 125 respectively connect to external devices/cables thereby.",
"[0006] System control circuit 134 contains circuits controlling the power and thermal solutions for the computer system.",
"[0007] FIG. 1B is another block diagram of a computer motherboard.",
"The motherboard comprises a CPU area 11 and a system core logic area 12 .",
"The difference between this system and that shown in FIG. 1A is system memory 113 connecting to the CPU 111 instead of the system core logic chipset 120 , allowing the CPU to directly access system memory for high speed computing without accessing system logic chipset 120 .",
"All other devices access system memory through system logic chipset 120 , which directs the requests to CPU 111 .",
"[0008] Conventional motherboards comprise core logic chipsets and CPU configurations that cannot be changed.",
"Installation of a CPU not compatible with the initial CPU socket requires replacement of motherboard, and possibly related devices, representing considerable inconvenience and cost.",
"SUMMARY [0009] A method and device providing multiple CPU configuration of a computer system are disclosed.",
"A motherboard supporting the device is also provided.",
"When a module with a first CPU is not connected to the motherboard via an expansion connector, a second CPU is connected with the system logic unit, and the expansion connector is disconnected from the system logic unit.",
"When the module is connected to the expansion connector, the second CPU is disconnected from the system logic unit, and the system logic unit is electrically connected with the expansion connector.",
"[0010] Additional features and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.",
"The features and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.",
"[0011] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.",
"DESCRIPTION OF THE DRAWINGS [0012] The accompanying drawings, incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the features, advantages, and principles of the invention.",
"[0013] FIGS. 1A and 1B are block diagrams of conventional computer systems.",
"[0014] FIG. 2 is a block diagram of a motherboard according to an embodiment of the invention.",
"[0015] FIG. 3 is a block diagram of a module applied with the motherboard of FIG. 2 .",
"[0016] FIG. 4 is a block diagram of a motherboard according to another embodiment of the invention.",
"[0017] FIG. 5 is a block diagram of a module applied with the motherboard of FIG. 4 .",
"DETAILED DESCRIPTION [0018] The invention is adaptive to change the CPU configuration in a computer system.",
"Various core logic chipsets support more than one type of CPU.",
"Bus signals between the system core logic chipset and an initial CPU, switched to connect with another upgraded CPU, allow an existing motherboard to accommodate different types of CPUs.",
"A module is provided to carry the second CPU for upgrading.",
"An expansion connector on the motherboard connects the module.",
"When the module connects to the expansion connector, the core logic chipset is disconnected from the initial CPU interface, and electrically connected to the expansion connector, to communicate with the upgraded CPU carried by the module.",
"A bus switching device selectively switches the connection to the core logic chipset between the initial CPU interface and the expansion connector.",
"[0019] The system memory may connect to the CPU rather than the core logic chipset.",
"The module must comprise system memory devices if the upgraded CPU on the module controls the memory interface.",
"[0020] The bus switching device can be a set of jumpers set to connect the system core logic chipset to the initial CPU or to the expansion connector, or a bus switching IC chip receiving a control signal generated in the motherboard, which sets the signal to a first state to control the bus switching IC to connect the core logic chipset with the initial CPU when the expansion connector is empty, and a second state to control the bus switching IC to connect the core logic chipset with the expansion connector when the expansion connector connects to the module.",
"The bus switching device disconnects the unused device and its related bus routing from the active bus, improving the signal integrity by preventing the loading and signal reflection caused by the unused device and the is bus routing.",
"[0021] FIG. 2 is a block diagram of a motherboard according to an embodiment of the invention.",
"The motherboard comprises a CPU area 21 , a system logic area 22 , a bus switching device 23 and an expansion connector 24 .",
"[0022] CPU area 21 comprises a CPU 211 , assembled initial or connecting to the motherboard through an initial CPU socket.",
"The CPU area 21 further comprises other devices connect directly to the second CPU 211 but the system logic area 22 .",
"For example, if CPU 211 connects directly to a system memory, the CPU area 21 comprises system memory (not shown).",
"The CPU area 21 further comprises control circuits (not shown) controlling the power supply and thermal solutions of the CPU area 21 .",
"[0023] System logic area 22 connects to bus switching device 23 via bus 221 .",
"The bus switching device 23 connects to CPU area 21 via bus 2211 and the expansion connector 24 via the bus 2212 .",
"The bus switching device 23 electrically connects the signals of the bus 221 to the signals of bus 2211 if the expansion connector 24 is not connected to any device.",
"The system logic area 22 connects to the second CPU area 21 and forms a complete system structure that boots and computes normally.",
"[0024] FIG. 3 shows a block diagram of a module applicable with the motherboard of FIG. 2 .",
"The module 31 comprises a CPU area 310 and a signal connector 312 connecting with the expansion connector 24 .",
"CPU 311 can be assembled initial or connect to the CPU area 310 through an initial CPU socket.",
"The module 31 further comprises other devices which connect directly to the first CPU 311 .",
"For example, if the first CPU 311 connects directly to the system memory, the module 31 comprises system memory (not shown).",
"[0025] The bus switching device 23 electrically connects the signals of the bus 221 with the signals of the bus 2212 if the expansion connector 24 is connected to the module 31 .",
"The system logic area 22 connects to the first CPU area 310 and forms a complete system structure that boots and computes normally.",
"[0026] FIG. 4 is a block diagram of a motherboard according to another embodiment of the invention.",
"The motherboard comprises a CPU area 41 , a system logic area 42 , a bus switching device 44 and an expansion connector 43 .",
"[0027] The CPU area 41 comprises a CPU 411 (AMD Athelon-64 754 pin), assembled initial or connecting to the motherboard through an initial CPU socket.",
"[0028] Because the AMD Athelon-64 754 pin CPU comprises a single channel DDR SDRAM interface, the CPU area 41 further comprises two DDR SDRAM sockets 412 to connect system memory devices.",
"The CPU area 41 further comprises CPU control circuits 413 controlling the power supply and thermal solutions for the second CPU area 41 .",
"[0029] The system logic area 42 comprises the system core logic unit 420 (SIS 760 Northbridge and SIS964 Southbridge system core logic chipset).",
"The system logic area 42 further comprises all other devices not directly connected to the CPU area 41 .",
"[0030] The system logic area 42 connects to the bus switching device 43 via the bus 421 .",
"The bus switching device 44 connects to the CPU area 41 via the bus 4211 and to the expansion connector 43 via the bus 4212 .",
"The bus switching device 44 electrically connects the signals of the bus 421 with the signals of the bus 4211 if the expansion connector 43 is not connected to any device.",
"The system logic area 42 connects to the CPU area 41 and forms a complete system structure that boots and computes normally.",
"[0031] FIG. 5 is a block diagram of a module applicable with the motherboard of t FIG. 4 .",
"The module 51 comprises a CPU 511 (AMD Athelon-64 939 pin CPU) and a signal connector 516 connecting with the expansion connector 43 , assembled initial or connecting to the module through an initial CPU socket.",
"[0032] The module 51 further comprises other devices directly connected to the CPU but not the system logic area 42 .",
"Because the AMD Athelon-64 939 pin CPU comprises dual channel DDR SDRAM interfaces, the module 51 further comprises four DDR SDRAM sockets ( 5121 , 5122 ) to connect system memory devices.",
"The module 51 further comprises CPU control circuits 53 controlling power supply and thermal solutions of the module 51 .",
"[0033] The bus switching device 44 electrically connects the signals of the bus 421 with the signals of the bus 4212 if the expansion connector 43 is connected to the module 51 .",
"The system logic area 42 connects to the module 51 and forms a complete system structure that could be boot up and compute normally.",
"[0034] The invention enables replacement of CPUs in a computer system, reducing cost and inconvenience.",
"[0035] While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto.",
"Those who are skilled in this technology can still make various alterations and modifications without departing from the scope and spirit of this invention.",
"Therefore, the scope of the present invention shall be defined and protected by the following claims and their equivalents."
] |
CROSS-REFERENCE TO RELATED-APPLICATIONS
[0001] This application is a Continuation-in-Part to U.S. Ser. No. 09/842,773, filed Apr. 25, 2001 (Attorney Docket No. GALL0010).
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The invention relates generally to wireless headphones and speakers and, more particularly, is directed to wireless headphones and speakers in which a satisfactory receiving condition is always maintained regardless of the condition and position.
[0004] 2. Description of the Prior Art
[0005] A wireless headphone system has recently been developed, in which a signal is transmitted through infrared rays from a transmitter and received at a remote position from the transmitter, so a listener can enjoy music. Japanese Laid-Open Patent Gazette No. 55-82596 describes a wireless headphone using infrared rays. This headphone is a wireless-type headphone, so that the usable range the user uses the headphone is not limited by a headphone cord. Further, using infrared rays prevents the wireless headphone from interfering with other radio waves. An infrared signal transmitted from a transmitter is received by a light-receiving element provided on a top portion, of a headband portion, of the wireless headphone. A signal outputted from the light-receiving element is supplied through an amplifier. A demodulating circuit and a reproducing circuit are powered by a power supply source such as a battery incorporated within the headphone. The receive signal is demodulated and reproduced in the headphone unit portion.
[0006] Abe, Wireless Headphones, U.S. Pat. No. 5,095,382, Mar. 10, 1992 teaches the use of multiple receivers on the headphones. This is done to increase the number of locations where the transmitted signal is received. This also reduces the likelihood that the signal is not received.
[0007] The problem with these solutions is that they focus only on improving the receiver, not the transmitter. Irrespective of how many receivers are put on a pair of headphones, it still does not receive a signal if there is no signal at that location. Multiple transmitters can be used to increase coverage, but this results in greatly increased costs and occupies more space. What is needed is a solution that improves the coverage of an infrared transmitter without greatly increasing the cost or space used.
[0008] Similarly, wireless speakers receive a transmitted infrared signal from a transmitter. The problem with current solutions is they take time to setup because most transmitters have limited coverage. Much time must be taken to properly place the speakers, and to ensure that they can receive the signal. What is need is a method to improve infrared signal coverage.
SUMMARY OF THE INVENTION
[0009] A method and apparatus is disclosed which provides for a wireless method to transmit a signal from a stereo to wireless headphones or speakers. Typically the signal is analog, but the signal may also contain data. An infrared beam transmitter diverges its signal by passing through a concave lens. The divergent beam has a wider range than a non-divergent signal. The beam is designed to bounce off of walls, ceilings and floors before reaching the receiver on the headphones/speakers. This way, a person wearing headphones can move about the coverage area without losing the signal, or speakers may be placed anywhere in a room, without worry that the signal is not received.
[0010] The receiver may also have a convex lens affixed to it so as to converge the transmitted signal. The convex lens focuses the signal so that transmitter can better interpret it. The signal may also be polarized so that the receiver filters out ambient light. Ambient light causes signal noise. Thus, filtering out the noise increases signal to noise ratio.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] [0011]FIG. 1 is a diagram illustrating a pair of headphones and a transmitter according to the invention;
[0012] [0012]FIG. 2 is a diagram illustrating a transmitter with a concave lens according to the invention;
[0013] [0013]FIG. 3 is a diagram illustrating a receiver with a concave and convex lens according to the invention;
[0014] [0014]FIG. 4 is a diagram illustrating a transmitter with a polarizer according to the invention;
[0015] [0015]FIG. 5 is a diagram illustrating a receiver with a polarizer according to the invention;
[0016] [0016]FIG. 6 is diagram illustrating linearly polarized light according to the invention;
[0017] [0017]FIGS. 7A and 7B are diagrams illustrating linearly polarized light over an angular range according to the invention;
[0018] [0018]FIG. 8 is a diagram illustrating the light spectrum,
[0019] [0019]FIGS. 9A, 9B and 9 C are diagrams illustrating a counter-weighted receiver according to the invention;
[0020] [0020]FIGS. 10A, 10B and 10 C are diagrams illustrating a reflective signal according to the invention;
[0021] [0021]FIG. 11 is a diagram illustrating a parabolic deflector according to the present invention;
[0022] [0022]FIG. 12 is a diagram illustrating an infrared receiver combined with selfamplified, wireless speakers;
[0023] [0023]FIG. 13 is a diagram illustrating a sound encoder that lies in line between the input television signal producer and a television; and
[0024] [0024]FIG. 14 is a diagram illustrating rear surround speakers mounted onto a stand with an amplifier.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] [0025]FIG. 1 illustrates a wireless headphone system according to an embodiment of the present invention, which comprises a transmitter 1 and a wireless headphone 2 . A transmitted infra-red light signal transmitted from the transmitter 1 is received by the wireless headphone 2 which in turn, reproduces an audio signal from the received light signal and supplies the same to unit portions 11 and 12 so as to be heard by the listener. The wireless headphone is powered by a battery.
[0026] As shown in FIG. 1, the transmitter 1 is generally comprised of a transmitter body 3 and a leg or base 4 that supports the transmitter body 3 . An audio signal is supplied to the transmitter from an audio apparatus through an input cable (not shown), whereupon the audio signal is converted to a modulated infrared transmission light signal, which is transmitted from a light-transmitting portion 5 of the transmitter 1 . The transmitter body 3 is adapted to be rotatable, relative to the base 4 , so as to vary the direction in which the transmission light signal is transmitted.
[0027] As shown in FIG. 1, the wireless headphone 2 is generally comprised of a headband portion 8 and a pair of headphone unit portions 11 and 12 , which are supported by the two end portions of the head band portion 8 through hanger portions 9 and 10 , respectively. The headphone unit portions 11 and 12 each incorporate speakers therein (not shown). Dial 14 is used to adjust the sound volume.
[0028] Wireless headphone 2 is provided with light receiving portions 16 , 17 and 18 at three portions of headphone 2 , that is, the central top portion or top portion of the head band portion 8 and the front side portions of the left and right headphone unit portions 11 and 12 . The light receiving portions 16 , 17 and 18 are covered with filter caps 16 a, 17 a and 18 a, respectively which, in a preferred embodiment, are pervious only to infrared signals.
[0029] The light-receiving portion 16 is provided on the top portion of the headband portion 8 . The received transmitted light signal is demodulated to provide an audio signal, which is reproduced by the headphone unit portions 11 and 12 as an audio sound.
[0030] The wireless headphone system receives a transmitted light signal, even when the listener wearing the headphone turns his or her head in any direction. That is, one of the three light receiving portions 16 , 17 and 18 receives the transmitted light signal. The wireless headphones include electronic circuits that may include an amplifying circuit. A circuit board is located within a filter cap for supporting a light-receiving element.
[0031] Three light receiving portions 16 , 17 and 18 are provided on the top portion of the headband portion 8 and on the respective headphone unit portions 11 and 12 , as previously described. As a result, even when one of the light receiving portions is hidden by the listener's hair, other light receiving portions receive the transmitted light signal from the transmitter 1 .
[0032] [0032]FIG. 2 illustrates a preferred embodiment of the transmitter 200 . In this embodiment, a light-emitting element 210 emits an infrared signal 220 . The signal is diverged through a plano-concave lens 230 . The effect of a divergent signal 240 is a signal that has a wider swath than a non-divergent signal 220 , and thus there is more area covered by the signal. Typically the lens 230 is constructed of glass, plastic or other material with similar refractive qualities.
[0033] [0033]FIG. 3 illustrates a receiver 300 according to a preferred embodiment. A plano-concave lens 310 is placed so as to first receive incoming infrared signals 240 . The piano-concave lens 310 is placed so as to converge the incoming signal 240 and produce a signal that has a substantially straight pattern 320 . The piano-concave lens 310 can receive signals at high incident angles. After the signal passes through the plano-concave lens, it passes through a piano-convex lens 330 . The piano-convex lens converges the signal onto the receiver potion 340 .
[0034] [0034]FIGS. 4 and 5 illustrate another embodiment where the signal is transmitted through a linear polarizer 410 at the transmitter 210 , and received through a similarly orientated linear polarizer 510 at the receiver. Light can be represented as a transverse electromagnetic wave made up of mutually perpendicular, fluctuating electric and magnetic fields. The light has an electric field and a magnetic field each lying in perpendicular planes, propagating in the same direction.
[0035] The sinusoidally varying electric field can be thought of as a length of rope held by two children at opposite ends. The children begin to displace the ends in such a way that the rope moves in a plane, either up and down, left and right, or at any angle in between.
[0036] Ordinary white light is made up of waves that fluctuate at all possible angles. Light is considered to be linearly polarized when it contains waves that only fluctuate in one specific plane. It is as it the rope is strung through a picket fence—the wave can move up and down, but motion is blocked in any other direction. A polarizer is a material that allows only light with a specific angle of vibration to pass through. The direction of fluctuation passed by the polarizer is called the easy axis.
[0037] Linear polarization is merely a special case of circularly polarized light. In FIG. 6, consider two light waves, one polarized in the YZ 620 plane and the other in the XY plane 610 . If the waves reach their maximum and minimum points at the same time, their vector sum leads to one wave, linearly polarized at 45 degrees. Similarly, if the two waves are 180 degrees out of phase, the resultant is linearly polarized at 45 degrees in the opposite sense (not shown).
[0038] The effect of using polarized light is that the linear polarizer at the receiver, substantially screens out light that is not in the same plane as the linearly polarized signal from the transmitter. This increases the signal to noise ratio, the non-signal light considered to be noise. Additionally, the polarizer allows the use of a less sensitive receiver, resulting in a cost savings.
[0039] In another embodiment, the linear polarizers transmit and receive the signal over an angular range, for example thirty degrees. The effect of transmitting and receiving the signal over an angular range is to decrease the likelihood that the respective polarizers are out of alignment, which causes a lack of signal reception at the receiver. FIG. 7A, illustrates a signal 710 created from a linear polarizer at the transmitter, where the signal lies on a linear vertical plane, a user who has tilted his head to the left 720 , and the corresponding orientation of the linear polarizer 730 at the receiver. The angled orientation of the receiver polarizer 730 , causes the polarizer at the receiver, and the polarizer at the transmitter to be out of alignment. This results in much signal being lost and not received by the receiver.
[0040] [0040]FIG. 7B, illustrates where a polarizer is designed to receive a signal at a range of angles 740 . The transmitter emits a linearly polarized signal 710 that lies in the vertical plane. As the user angles his head 720 , the polarizer 740 at the receiver, stays in alignment with the polarizer at the transmitter, because no part of the signal 710 lies outside the area covered by the polarizer 740 at the receiver. Thus, because the receiver is able to fully receive the incoming signal, there is no signal loss.
[0041] In another preferred embodiment, a filter is used to filter out frequencies of light that are not in the infrared range. A film coating is applied to the receiver that allows infrared light to pass through, but absorbs or reflects light of other frequencies.
[0042] In another embodiment, a computing element, at the receiver, samples the whole signal and filters out frequencies that do lie in the infrared spectrum. As can be seen if FIG. 8, the infrared spectrum occupies a certain range of frequencies. Those frequencies that are higher 820 and lower 830 are filtered out. The result is an infrared signal that has a higher signal to noise ratio than an unfiltered signal.
[0043] [0043]FIGS. 9A, 9B and 9 C illustrate another embodiment of the invention where a counterweight 910 is attached to the receiver 900 , such that the receiving portion 930 always lies substantially orientated in the same way. FIG. 9A illustrates a side view of the receiver 900 , where the receiver 900 consists of a receiving portion 930 , protruding from a contoured container 940 . The receiver portion 930 is rotatably contained in the contoured container 940 , and is attached to the container at a central point 950 .
[0044] [0044]FIG. 9B illustrates a frontal view of the receiver, where the receiver portion 930 of the receiver lies in a slot 960 in the container 940 so that the receiver portion 930 can freely rotate without the container interfering with the rotation of the receiver portion. The counterweight 910 is adapted with the receiver 900 , so that as the orientation of the receiver 900 changes, the receiver portion 930 rotates relative to the container 940 such that the receiving portion 930 remains substantially orientated the same.
[0045] The counterweight does this by effectively moving the center of gravity of the receiver away from the volumetric center of gravity. As the receiver is shifted, the receiver portion rotates around the centrally hinged position 950 , such that the receiver 900 returns to its original position, to maintain static and dynamic equilibrium. FIG. 9C illustrates another embodiment where the counterweight 970 is designed to keep the receiving portion 930 directed in an upward direction.
[0046] [0046]FIGS. 10A, 10B, and 10 C illustrate another preferred embodiment of the invention where an array of transmitters are used. At least one transmitter is aimed such a way that the infrared signal is incident upon a receiver along a direct path, while the other transmitters 1010 , 1020 , 1030 are aimed to have their signal 1012 , 1022 , 1032 to be received by a receiver 1000 after reflecting off of an object, such as, a ceiling 1011 , floor 1021 or wall 1031 . It is also contemplated that the signal may reflect off of objects such as furniture, statues, wall hanging, and even family pets.
[0047] [0047]FIG. 11 illustrates another preferred embodiment where a parabolic deflector 1100 is combined with a receiver 1120 , to increase the amount of signal received. The conical deflector is attached to a frontal portion of a receiver 1120 . The interior of the deflector has high reflective qualities, causing an incident infrared signal 1140 to reflect off of its surface. The conical shape of the deflector causes a reflected signal 1130 to be incident upon the receiver 1120 . It is contemplated that the deflector is adjustable to maximize the signal reflection.
[0048] In another embodiment of the invention, the infrared transmitter and receiver are used to transmit data across a distance. For example, a transmitter/receiver combination can be used for connecting with cable Internet. A typical Internet cable connection has a wire lead passing from the exterior of the home, through a hole in the wall, to an external network card that is connected to the computer. Using the transmitter/receiver combination, the cable passes through the hole in the wall, and in close proximity to the wall, plugs into the transmitter, which transmits a data signal. The receiver is integrated with the external modem, and receives the Internet signal from the transmitter, and the signal is transmitted from the network card to the computer.
[0049] [0049]FIG. 12 illustrates another preferred embodiment where, an infrared receiver 1210 , 1211 is combined with self-amplified, wireless speakers 1220 , 1221 . The speakers 1220 , 1221 receive an input signal 1230 from an infrared transmitter 1205 . The speakers can be used to produce stereo or surround sound. The speakers 1220 , 1221 are placed in locations within the listening environment such that they produce an enjoyable listening experience.
[0050] When used as surround sound speakers, the television's speakers are used to produce front and/or center channel sound. FIG. 13 illustrates a sound encoder 1310 that lies in line between the input television signal producer 1320 , and the television 1330 . The encoder 1310 processes the input stereo signal 1321 and directs front and center channel signals 1331 to the television 1330 , and sends a surround sound signal 1341 to the transmitter 1340 , which is then sent to the wireless speakers. Surround sound is produced from a stereo input signal by delaying the signal, so as to produce a spatial effect. Also, the surround sound volume level is typically lower than the front and center channels. It is also contemplated that a front center speaker is incorporated with the encoder such that the center speaker reproduces center channel signals from the encoder.
[0051] In another embodiment, a decoder processes a multi-channel surround encoded signal. The decoder directs front and center channel signals to the television, and surround sound signals to the transmitter.
[0052] In another embodiment of the invention, rear surround speakers 1410 are mounted onto a stand 1420 as shown in FIG. 14. An amplifier 1430 is used to amplify a rear surround sound signal received by an infrared receiver and to reproduce them through the rear surround speakers.
[0053] Although the invention is described herein with reference to the preferred embodiment, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention. Accordingly, the invention should only be limited by the claims included below. | A wireless method and apparatus for transmitting signal, for example, from a source, to headphones or speakers, while allowing relatively unrestricted range of movement/placement for the headphones or speakers. An infrared transmitter diverges its signal by passing the signal through a concave lens. The signal is processed to bounce off of objects, such as, walls, ceilings and floors before reaching the receiver on the headphones/speakers. The receiver has a convex lens affixed to it, so as to converge the transmitted signal. The signal is polarized so that ambient light is filtered. | Identify the most important claim in the given context and summarize it | [
"CROSS-REFERENCE TO RELATED-APPLICATIONS [0001] This application is a Continuation-in-Part to U.S. Ser.",
"No. 09/842,773, filed Apr. 25, 2001 (Attorney Docket No. GALL0010).",
"BACKGROUND OF THE INVENTION [0002] 1.",
"Technical Field [0003] The invention relates generally to wireless headphones and speakers and, more particularly, is directed to wireless headphones and speakers in which a satisfactory receiving condition is always maintained regardless of the condition and position.",
"[0004] 2.",
"Description of the Prior Art [0005] A wireless headphone system has recently been developed, in which a signal is transmitted through infrared rays from a transmitter and received at a remote position from the transmitter, so a listener can enjoy music.",
"Japanese Laid-Open Patent Gazette No. 55-82596 describes a wireless headphone using infrared rays.",
"This headphone is a wireless-type headphone, so that the usable range the user uses the headphone is not limited by a headphone cord.",
"Further, using infrared rays prevents the wireless headphone from interfering with other radio waves.",
"An infrared signal transmitted from a transmitter is received by a light-receiving element provided on a top portion, of a headband portion, of the wireless headphone.",
"A signal outputted from the light-receiving element is supplied through an amplifier.",
"A demodulating circuit and a reproducing circuit are powered by a power supply source such as a battery incorporated within the headphone.",
"The receive signal is demodulated and reproduced in the headphone unit portion.",
"[0006] Abe, Wireless Headphones, U.S. Pat. No. 5,095,382, Mar. 10, 1992 teaches the use of multiple receivers on the headphones.",
"This is done to increase the number of locations where the transmitted signal is received.",
"This also reduces the likelihood that the signal is not received.",
"[0007] The problem with these solutions is that they focus only on improving the receiver, not the transmitter.",
"Irrespective of how many receivers are put on a pair of headphones, it still does not receive a signal if there is no signal at that location.",
"Multiple transmitters can be used to increase coverage, but this results in greatly increased costs and occupies more space.",
"What is needed is a solution that improves the coverage of an infrared transmitter without greatly increasing the cost or space used.",
"[0008] Similarly, wireless speakers receive a transmitted infrared signal from a transmitter.",
"The problem with current solutions is they take time to setup because most transmitters have limited coverage.",
"Much time must be taken to properly place the speakers, and to ensure that they can receive the signal.",
"What is need is a method to improve infrared signal coverage.",
"SUMMARY OF THE INVENTION [0009] A method and apparatus is disclosed which provides for a wireless method to transmit a signal from a stereo to wireless headphones or speakers.",
"Typically the signal is analog, but the signal may also contain data.",
"An infrared beam transmitter diverges its signal by passing through a concave lens.",
"The divergent beam has a wider range than a non-divergent signal.",
"The beam is designed to bounce off of walls, ceilings and floors before reaching the receiver on the headphones/speakers.",
"This way, a person wearing headphones can move about the coverage area without losing the signal, or speakers may be placed anywhere in a room, without worry that the signal is not received.",
"[0010] The receiver may also have a convex lens affixed to it so as to converge the transmitted signal.",
"The convex lens focuses the signal so that transmitter can better interpret it.",
"The signal may also be polarized so that the receiver filters out ambient light.",
"Ambient light causes signal noise.",
"Thus, filtering out the noise increases signal to noise ratio.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0011] [0011 ]FIG. 1 is a diagram illustrating a pair of headphones and a transmitter according to the invention;",
"[0012] [0012 ]FIG. 2 is a diagram illustrating a transmitter with a concave lens according to the invention;",
"[0013] [0013 ]FIG. 3 is a diagram illustrating a receiver with a concave and convex lens according to the invention;",
"[0014] [0014 ]FIG. 4 is a diagram illustrating a transmitter with a polarizer according to the invention;",
"[0015] [0015 ]FIG. 5 is a diagram illustrating a receiver with a polarizer according to the invention;",
"[0016] [0016 ]FIG. 6 is diagram illustrating linearly polarized light according to the invention;",
"[0017] [0017 ]FIGS. 7A and 7B are diagrams illustrating linearly polarized light over an angular range according to the invention;",
"[0018] [0018 ]FIG. 8 is a diagram illustrating the light spectrum, [0019] [0019 ]FIGS. 9A, 9B and 9 C are diagrams illustrating a counter-weighted receiver according to the invention;",
"[0020] [0020 ]FIGS. 10A, 10B and 10 C are diagrams illustrating a reflective signal according to the invention;",
"[0021] [0021 ]FIG. 11 is a diagram illustrating a parabolic deflector according to the present invention;",
"[0022] [0022 ]FIG. 12 is a diagram illustrating an infrared receiver combined with selfamplified, wireless speakers;",
"[0023] [0023 ]FIG. 13 is a diagram illustrating a sound encoder that lies in line between the input television signal producer and a television;",
"and [0024] [0024 ]FIG. 14 is a diagram illustrating rear surround speakers mounted onto a stand with an amplifier.",
"DESCRIPTION OF THE PREFERRED EMBODIMENT [0025] [0025 ]FIG. 1 illustrates a wireless headphone system according to an embodiment of the present invention, which comprises a transmitter 1 and a wireless headphone 2 .",
"A transmitted infra-red light signal transmitted from the transmitter 1 is received by the wireless headphone 2 which in turn, reproduces an audio signal from the received light signal and supplies the same to unit portions 11 and 12 so as to be heard by the listener.",
"The wireless headphone is powered by a battery.",
"[0026] As shown in FIG. 1, the transmitter 1 is generally comprised of a transmitter body 3 and a leg or base 4 that supports the transmitter body 3 .",
"An audio signal is supplied to the transmitter from an audio apparatus through an input cable (not shown), whereupon the audio signal is converted to a modulated infrared transmission light signal, which is transmitted from a light-transmitting portion 5 of the transmitter 1 .",
"The transmitter body 3 is adapted to be rotatable, relative to the base 4 , so as to vary the direction in which the transmission light signal is transmitted.",
"[0027] As shown in FIG. 1, the wireless headphone 2 is generally comprised of a headband portion 8 and a pair of headphone unit portions 11 and 12 , which are supported by the two end portions of the head band portion 8 through hanger portions 9 and 10 , respectively.",
"The headphone unit portions 11 and 12 each incorporate speakers therein (not shown).",
"Dial 14 is used to adjust the sound volume.",
"[0028] Wireless headphone 2 is provided with light receiving portions 16 , 17 and 18 at three portions of headphone 2 , that is, the central top portion or top portion of the head band portion 8 and the front side portions of the left and right headphone unit portions 11 and 12 .",
"The light receiving portions 16 , 17 and 18 are covered with filter caps 16 a, 17 a and 18 a, respectively which, in a preferred embodiment, are pervious only to infrared signals.",
"[0029] The light-receiving portion 16 is provided on the top portion of the headband portion 8 .",
"The received transmitted light signal is demodulated to provide an audio signal, which is reproduced by the headphone unit portions 11 and 12 as an audio sound.",
"[0030] The wireless headphone system receives a transmitted light signal, even when the listener wearing the headphone turns his or her head in any direction.",
"That is, one of the three light receiving portions 16 , 17 and 18 receives the transmitted light signal.",
"The wireless headphones include electronic circuits that may include an amplifying circuit.",
"A circuit board is located within a filter cap for supporting a light-receiving element.",
"[0031] Three light receiving portions 16 , 17 and 18 are provided on the top portion of the headband portion 8 and on the respective headphone unit portions 11 and 12 , as previously described.",
"As a result, even when one of the light receiving portions is hidden by the listener's hair, other light receiving portions receive the transmitted light signal from the transmitter 1 .",
"[0032] [0032 ]FIG. 2 illustrates a preferred embodiment of the transmitter 200 .",
"In this embodiment, a light-emitting element 210 emits an infrared signal 220 .",
"The signal is diverged through a plano-concave lens 230 .",
"The effect of a divergent signal 240 is a signal that has a wider swath than a non-divergent signal 220 , and thus there is more area covered by the signal.",
"Typically the lens 230 is constructed of glass, plastic or other material with similar refractive qualities.",
"[0033] [0033 ]FIG. 3 illustrates a receiver 300 according to a preferred embodiment.",
"A plano-concave lens 310 is placed so as to first receive incoming infrared signals 240 .",
"The piano-concave lens 310 is placed so as to converge the incoming signal 240 and produce a signal that has a substantially straight pattern 320 .",
"The piano-concave lens 310 can receive signals at high incident angles.",
"After the signal passes through the plano-concave lens, it passes through a piano-convex lens 330 .",
"The piano-convex lens converges the signal onto the receiver potion 340 .",
"[0034] [0034 ]FIGS. 4 and 5 illustrate another embodiment where the signal is transmitted through a linear polarizer 410 at the transmitter 210 , and received through a similarly orientated linear polarizer 510 at the receiver.",
"Light can be represented as a transverse electromagnetic wave made up of mutually perpendicular, fluctuating electric and magnetic fields.",
"The light has an electric field and a magnetic field each lying in perpendicular planes, propagating in the same direction.",
"[0035] The sinusoidally varying electric field can be thought of as a length of rope held by two children at opposite ends.",
"The children begin to displace the ends in such a way that the rope moves in a plane, either up and down, left and right, or at any angle in between.",
"[0036] Ordinary white light is made up of waves that fluctuate at all possible angles.",
"Light is considered to be linearly polarized when it contains waves that only fluctuate in one specific plane.",
"It is as it the rope is strung through a picket fence—the wave can move up and down, but motion is blocked in any other direction.",
"A polarizer is a material that allows only light with a specific angle of vibration to pass through.",
"The direction of fluctuation passed by the polarizer is called the easy axis.",
"[0037] Linear polarization is merely a special case of circularly polarized light.",
"In FIG. 6, consider two light waves, one polarized in the YZ 620 plane and the other in the XY plane 610 .",
"If the waves reach their maximum and minimum points at the same time, their vector sum leads to one wave, linearly polarized at 45 degrees.",
"Similarly, if the two waves are 180 degrees out of phase, the resultant is linearly polarized at 45 degrees in the opposite sense (not shown).",
"[0038] The effect of using polarized light is that the linear polarizer at the receiver, substantially screens out light that is not in the same plane as the linearly polarized signal from the transmitter.",
"This increases the signal to noise ratio, the non-signal light considered to be noise.",
"Additionally, the polarizer allows the use of a less sensitive receiver, resulting in a cost savings.",
"[0039] In another embodiment, the linear polarizers transmit and receive the signal over an angular range, for example thirty degrees.",
"The effect of transmitting and receiving the signal over an angular range is to decrease the likelihood that the respective polarizers are out of alignment, which causes a lack of signal reception at the receiver.",
"FIG. 7A, illustrates a signal 710 created from a linear polarizer at the transmitter, where the signal lies on a linear vertical plane, a user who has tilted his head to the left 720 , and the corresponding orientation of the linear polarizer 730 at the receiver.",
"The angled orientation of the receiver polarizer 730 , causes the polarizer at the receiver, and the polarizer at the transmitter to be out of alignment.",
"This results in much signal being lost and not received by the receiver.",
"[0040] [0040 ]FIG. 7B, illustrates where a polarizer is designed to receive a signal at a range of angles 740 .",
"The transmitter emits a linearly polarized signal 710 that lies in the vertical plane.",
"As the user angles his head 720 , the polarizer 740 at the receiver, stays in alignment with the polarizer at the transmitter, because no part of the signal 710 lies outside the area covered by the polarizer 740 at the receiver.",
"Thus, because the receiver is able to fully receive the incoming signal, there is no signal loss.",
"[0041] In another preferred embodiment, a filter is used to filter out frequencies of light that are not in the infrared range.",
"A film coating is applied to the receiver that allows infrared light to pass through, but absorbs or reflects light of other frequencies.",
"[0042] In another embodiment, a computing element, at the receiver, samples the whole signal and filters out frequencies that do lie in the infrared spectrum.",
"As can be seen if FIG. 8, the infrared spectrum occupies a certain range of frequencies.",
"Those frequencies that are higher 820 and lower 830 are filtered out.",
"The result is an infrared signal that has a higher signal to noise ratio than an unfiltered signal.",
"[0043] [0043 ]FIGS. 9A, 9B and 9 C illustrate another embodiment of the invention where a counterweight 910 is attached to the receiver 900 , such that the receiving portion 930 always lies substantially orientated in the same way.",
"FIG. 9A illustrates a side view of the receiver 900 , where the receiver 900 consists of a receiving portion 930 , protruding from a contoured container 940 .",
"The receiver portion 930 is rotatably contained in the contoured container 940 , and is attached to the container at a central point 950 .",
"[0044] [0044 ]FIG. 9B illustrates a frontal view of the receiver, where the receiver portion 930 of the receiver lies in a slot 960 in the container 940 so that the receiver portion 930 can freely rotate without the container interfering with the rotation of the receiver portion.",
"The counterweight 910 is adapted with the receiver 900 , so that as the orientation of the receiver 900 changes, the receiver portion 930 rotates relative to the container 940 such that the receiving portion 930 remains substantially orientated the same.",
"[0045] The counterweight does this by effectively moving the center of gravity of the receiver away from the volumetric center of gravity.",
"As the receiver is shifted, the receiver portion rotates around the centrally hinged position 950 , such that the receiver 900 returns to its original position, to maintain static and dynamic equilibrium.",
"FIG. 9C illustrates another embodiment where the counterweight 970 is designed to keep the receiving portion 930 directed in an upward direction.",
"[0046] [0046 ]FIGS. 10A, 10B, and 10 C illustrate another preferred embodiment of the invention where an array of transmitters are used.",
"At least one transmitter is aimed such a way that the infrared signal is incident upon a receiver along a direct path, while the other transmitters 1010 , 1020 , 1030 are aimed to have their signal 1012 , 1022 , 1032 to be received by a receiver 1000 after reflecting off of an object, such as, a ceiling 1011 , floor 1021 or wall 1031 .",
"It is also contemplated that the signal may reflect off of objects such as furniture, statues, wall hanging, and even family pets.",
"[0047] [0047 ]FIG. 11 illustrates another preferred embodiment where a parabolic deflector 1100 is combined with a receiver 1120 , to increase the amount of signal received.",
"The conical deflector is attached to a frontal portion of a receiver 1120 .",
"The interior of the deflector has high reflective qualities, causing an incident infrared signal 1140 to reflect off of its surface.",
"The conical shape of the deflector causes a reflected signal 1130 to be incident upon the receiver 1120 .",
"It is contemplated that the deflector is adjustable to maximize the signal reflection.",
"[0048] In another embodiment of the invention, the infrared transmitter and receiver are used to transmit data across a distance.",
"For example, a transmitter/receiver combination can be used for connecting with cable Internet.",
"A typical Internet cable connection has a wire lead passing from the exterior of the home, through a hole in the wall, to an external network card that is connected to the computer.",
"Using the transmitter/receiver combination, the cable passes through the hole in the wall, and in close proximity to the wall, plugs into the transmitter, which transmits a data signal.",
"The receiver is integrated with the external modem, and receives the Internet signal from the transmitter, and the signal is transmitted from the network card to the computer.",
"[0049] [0049 ]FIG. 12 illustrates another preferred embodiment where, an infrared receiver 1210 , 1211 is combined with self-amplified, wireless speakers 1220 , 1221 .",
"The speakers 1220 , 1221 receive an input signal 1230 from an infrared transmitter 1205 .",
"The speakers can be used to produce stereo or surround sound.",
"The speakers 1220 , 1221 are placed in locations within the listening environment such that they produce an enjoyable listening experience.",
"[0050] When used as surround sound speakers, the television's speakers are used to produce front and/or center channel sound.",
"FIG. 13 illustrates a sound encoder 1310 that lies in line between the input television signal producer 1320 , and the television 1330 .",
"The encoder 1310 processes the input stereo signal 1321 and directs front and center channel signals 1331 to the television 1330 , and sends a surround sound signal 1341 to the transmitter 1340 , which is then sent to the wireless speakers.",
"Surround sound is produced from a stereo input signal by delaying the signal, so as to produce a spatial effect.",
"Also, the surround sound volume level is typically lower than the front and center channels.",
"It is also contemplated that a front center speaker is incorporated with the encoder such that the center speaker reproduces center channel signals from the encoder.",
"[0051] In another embodiment, a decoder processes a multi-channel surround encoded signal.",
"The decoder directs front and center channel signals to the television, and surround sound signals to the transmitter.",
"[0052] In another embodiment of the invention, rear surround speakers 1410 are mounted onto a stand 1420 as shown in FIG. 14.",
"An amplifier 1430 is used to amplify a rear surround sound signal received by an infrared receiver and to reproduce them through the rear surround speakers.",
"[0053] Although the invention is described herein with reference to the preferred embodiment, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention.",
"Accordingly, the invention should only be limited by the claims included below."
] |
FIELD OF THE INVENTION
The present invention relates to over-the-door caddy organizers. More particularly, the invention is directed to a locking means for an over-the-door shelf organizer which allows collapsible transportation and subsequent assembly by an end-user.
BACKGROUND OF THE INVENTION
Household organizers which take advantage of existing structures and open, unused spaces are known in the art. For example, Ke Patent No. 4,846,430 discloses a door organizer which can be used to suspend garments, towels and the like. While maximizing the use of existing structures and unused space is convenient for end-users, manufacturers prefer compact organizers for easy shipping and reduced freight rates. Non-collapsible, single-piece units are costly to transport. They are also difficult to handle, store and display in retail space. It is therefore desirable to produce "knocked down" or multi-piece, collapsible versions of organizers.
Shelf or rack organizers specifically for suspending from the top aspects of a door are also known. Most currently known over-the-door organizers are unitary structures having a frame and shelves formed from coated steel wire. These single piece units are difficult to handle because their overall configurations do not conform well to conventional commercial packaging. They also require excessive storage space to accommodate their various shapes and sizes.
Attempts have been made to produce knocked down or collapsible over-the-door organizers. Generally, coated steel wire shelves are supported by vertical, metal tubing frame members which have mounting holes disposed in their sides to accept the coated wire. The ends are then capped with formed metal nuts. These joints are cheap and easy to manufacture, but they are unstable and the resulting assembly has poor structural integrity. This instability may cause physical distortion, especially when the door is swinging about its hinges.
Commercially successful over-the-door shelf organizers are disclosed in Emery Patent No. 5,460,279. Other configurations are illustrated in Design Pat. Nos. 354,412 and 365,239. But, the prior art designs do not provide an improved locking means which permits collapsible transportation, storage and assembly by the end-user.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a shelf organizer which is collapsible for cost-effective shipping, storage and display.
Another object of the present invention is to provide a collapsible shelf organizer with a novel locking means which delivers superior structural integrity.
Yet another object of the present invention is to provide a collapsible, over-the-door shelf organizer having structural elements which comprise a unique locking means for ease of assembly.
These and other objects will be apparent from the present disclosure.
SUMMARY OF THE INVENTION
The invention is a collapsible shelf organizer adapted for attachment to structures such as doors and the like. It comprises at least two vertically extending frame members each having at least one basket support element equipped with a retainer and terminal loop structure. The retainer of the basket support element can be a ball or sphere.
The shelf organizer further comprises at least one basket disposed between the vertically extending frame members. Each basket has an upper surface, lower surface and means for locking with the retainer and terminal loop structure of each basket support element. The shelf organizer further comprises a hanger bar having another means for locking with the upper and lower surfaces of the basket.
Each of the basket support elements operably connects to its vertically extending frame member so that the terminal loop structure of the basket support element is disposed along an axis extending substantially perpendicular to its specific vertically extending frame member.
The means for locking with the retainer and terminal loop structure of a basket support element comprises a grip lock and loop lock. The grip lock is adapted for engagement with the retainer and the loop lock is adapted for engagement with the loop structure on the basket support element.
The basket is further comprised of a rear portion and mid portion, with the upper and lower surfaces of the basket being disposed on the rear portion, and the mid portion further comprising a superior surface and dorsal surface. The upper and lower surfaces of the basket are adapted to engage the hanger bar. The means for locking the hanger bar to the basket comprises a gravity lock and a flange lock. The gravity lock further comprises a semi-circular piece and clasp portion, while the flange lock further comprises a semi-circular portion and lateral tip.
The semi-circular piece of the gravity lock is adapted for engagement with the dorsal surface of the mid portion of the basket, and the clasp portion of the gravity lock is adapted for engagement with the upper surface of the rear portion of the basket. The semi-circular portion of the flange lock is adapted for engagement with the superior surface of the mid portion of the basket, and the lateral tip of the flange lock is adapted for engagement with the lower surface of the rear portion of the basket.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of this invention, reference is made to the following detailed description in connection with the accompanying drawings.
FIG. 1 is a lower perspective view of the collapsible shelf organizer showing the preferred embodiment of the present invention with a portion of a door from which it suspends represented by phantom lines.
FIG. 2 is an exploded view of the individual components which constitute the preferred embodiment of the present invention.
FIGS. 3 and 4 are lower perspective views of alternate design choices for the over-the-door shelf organizer.
FIG. 5 shows the component pieces of the shelf organizer illustrated in FIGS. 1 and 2 in its collapsed state and neatly packed in a configuration suitable for cost-effective shipping, storage and display.
FIGS. 6A through 6C are a series of drawings showing one aspect of the locking means of the present invention.
FIGS. 7A and 7B are isolated, cut-away views of another aspect of the locking mechanism of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates the preferred embodiment of the present invention showing an assembled shelf organizer generally designated 10. The preferred embodiment is constructed principally of coated steel wire, but one skilled in the art can readily appreciate a variety of other possible materials suitable for this construction.
FIG. 2 shows that shelf organizer 10 comprises two vertically extending frame members 20 and 20', basket 30 and hanger bar 31. Vertical frame member 20, taken as representative, has circular member 28 at its uppermost portion. Circular member 28 has in its diameter cross wire 29 for attachment to semi-circular end 16 of hanger bracket 15.
Extending from vertical frame member 20 is basket support element 21. In the preferred embodiment shown in FIG. 2, support element 21 has a semi-circular shape with an upwardly facing concavity. Other design variations are possible depending on the aesthetic qualities preferred, and all variations are within the scope and spirit of this disclosure. Support element 21 extends orthogonally to the plane of frame member 20 and terminates in substantially closed loop structure 22 which extends from basket support element 21.
Basket 30 is comprised of front portion 34, mid portion 45 and rear portion 35. At each of its two ends, front portion 34 has loop locks 32 and 32' which are adapted for passage through, and releasable engagement with, the apertures formed in loop structures 22 and 22'. Mid portion 45 is shown in FIG. 2 with superior surface 48 and dorsal surface 49. Rear portion 35 has at each of its two ends grip locks 33 and 33'. These locks are adapted for releasable engagement with frame members 20 and 20' at ball retainers 23 and 23'.
Intermediate to grip lock 33 on rear portion 35 is lower surface 38. Lower surface 38 (on rear portion 35) and superior surface 48 (on mid portion 45) cooperate to form a flange lock which is further described below. Intermediate to grip lock 33' on rear portion 35 is upper surface 39. Upper surface 39 (on rear portion 35) and dorsal surface 49 (on mid portion 45) cooperate to form a gravity lock which is also described below.
Hanger bar 31 has at each of its two ends flange lock 36 and gravity lock 37, respectively. Flange lock 36 is comprised of semi-circular portion 88 which straightens and terminates at lateral tip 68. Gravity lock 37 is comprised of semi-circular piece 89 which straightens and terminates at clasp portion 69. Semi-circular portion 88 and lateral tip 68 (of flange lock 36) are adapted for releasable engagement with superior surface 48 (on mid portion 45) and lower surface 38 (on rear portion 35). Semi-circular piece 89 and clasp portion 69 (of gravity lock 37) are adapted for releasable engagement with dorsal surface 49 (on mid portion 45) and upper surface 39 (on rear portion 35). Hanger bar 31 is shown in FIG. 2 with hooks 40 for hanging suitable items such as clothing and the like.
FIGS. 3 and 4 are lower perspective views of alternate style choices for the over-the-door shelf organizer and demonstrate that the number of hooks (40' or 40") and their design configurations are a matter of practical and aesthetic choice.
FIG. 5 illustrates the components of the preferred shelf organizer (shown exploded in FIG. 2) in its collapsed state and packed in an optimum configuration for efficient shipping and storage. The ability to knock down the component pieces avoids protrusions and allows the entire product to be shipped within a small and confined package represented by phantom lines.
FIGS. 6A, 6B and 6C sequentially show how hanger bar 31 is mounted to basket 30 during assembly. FIG. 6A shows the initial placement of semi-circular portion 88 of flange lock 36 over superior surface 48 on mid portion 45, following the pathway designated with arrow X. Lateral tip 68 of flange lock 36 is then placed under lower surface 38 on rear portion 35, following the pathway designated with arrow Y.
FIG. 6B shows that semi-circular piece 89 of gravity lock 37 is next placed above dorsal surface 49 on mid portion 45 and allowed to descend following the pathway designated with arrow Z. Lateral tip 68 of flange lock 36 snaps under rear portion 35 and engages lower surface 38 on rear portion 35. FIG. 6C shows that flange lock 36 is biased into position by the cooperation of semi-circular portion 88 engaged to superior surface 48 of mid portion 45 and by lateral tip 68 engaged to lower surface 38 of rear portion 35. The descending weight of basket 30 snaps semi-circular piece 89 of gravity lock 37 onto dorsal surface 49 on mid portion 45, and simultaneously snaps clasp portion 69 of gravity lock 37 onto upper surface 39 on rear portion 35, which completes the attachment of hanger bar 31 to basket 30.
FIGS. 7A and 7B are isolated, cut-away views of another aspect of the locking mechanism of the preferred embodiment. FIG. 7A shows that basket 30 has loop lock 32 extending laterally from front portion 34. Loop lock 32 is adapted to fit through the aperture formed by closed loop structure 22 of basket support element 21. Forked grip lock 33 is adapted for slidable engagement with frame member 20 and comes to rest on ball retainer 23 to complete the lock as shown in FIG. 7B.
In overview, to assemble shelf organizer 10, hanger brackets 15 and 15' (see FIG. 1) are placed over the top of a suitable structure such as a door. Referring to FIGS. 1 and 2, cross wires 29 and 29' on the upper portions of vertical frame members 20 and 20' are slipped into semi-circular ends 16 and 16' of hanger brackets 15 and 15'. After spacing and centering suspended vertical frame members 20 and 20', basket 30 is placed between them and tipped forward so that rear portion 35 of basket 30 points in an upward direction as shown in FIG. 7A. Loop lock 32 is inserted through loop structure 22 of frame member 20. This is repeated on the opposite end of basket 30, with loop lock 32' inserted through loop structure 22' of frame member 20' (not shown).
Once loop locks 32 and 32' are in position, rear portion 35 of basket 30 is allowed to descend in a counter clockwise direction until grip lock 33 rests firmly on ball retainer 23 as shown in FIG. 7B. This action is simultaneously conducted on the opposite end of basket 30, with loop locks 32 and 32' rotating within loop structures 22 and 22' until grip lock 33' is firmly anchored on ball retainer 23' (not shown). Hanger 31 can be locked into basket 30 before or after vertical support frame members 20 and 20' are locked with basket 30.
Further modifications based on this disclosure will occur to persons skilled in the art. These modifications are within the scope and spirit of the present invention as defined by the following claims. | This invention is directed to a multipurpose, over-the-door shelf organizer. It is characterized by a unique, yet simple locking mechanism to form a stable frame with superior structural integrity. The device is easily assembled for end use application; and easily collapsed to facilitate storage and shipment. | Summarize the information, clearly outlining the challenges and proposed solutions. | [
"FIELD OF THE INVENTION The present invention relates to over-the-door caddy organizers.",
"More particularly, the invention is directed to a locking means for an over-the-door shelf organizer which allows collapsible transportation and subsequent assembly by an end-user.",
"BACKGROUND OF THE INVENTION Household organizers which take advantage of existing structures and open, unused spaces are known in the art.",
"For example, Ke Patent No. 4,846,430 discloses a door organizer which can be used to suspend garments, towels and the like.",
"While maximizing the use of existing structures and unused space is convenient for end-users, manufacturers prefer compact organizers for easy shipping and reduced freight rates.",
"Non-collapsible, single-piece units are costly to transport.",
"They are also difficult to handle, store and display in retail space.",
"It is therefore desirable to produce "knocked down"",
"or multi-piece, collapsible versions of organizers.",
"Shelf or rack organizers specifically for suspending from the top aspects of a door are also known.",
"Most currently known over-the-door organizers are unitary structures having a frame and shelves formed from coated steel wire.",
"These single piece units are difficult to handle because their overall configurations do not conform well to conventional commercial packaging.",
"They also require excessive storage space to accommodate their various shapes and sizes.",
"Attempts have been made to produce knocked down or collapsible over-the-door organizers.",
"Generally, coated steel wire shelves are supported by vertical, metal tubing frame members which have mounting holes disposed in their sides to accept the coated wire.",
"The ends are then capped with formed metal nuts.",
"These joints are cheap and easy to manufacture, but they are unstable and the resulting assembly has poor structural integrity.",
"This instability may cause physical distortion, especially when the door is swinging about its hinges.",
"Commercially successful over-the-door shelf organizers are disclosed in Emery Patent No. 5,460,279.",
"Other configurations are illustrated in Design Pat. Nos. 354,412 and 365,239.",
"But, the prior art designs do not provide an improved locking means which permits collapsible transportation, storage and assembly by the end-user.",
"OBJECTS OF THE INVENTION It is an object of the present invention to provide a shelf organizer which is collapsible for cost-effective shipping, storage and display.",
"Another object of the present invention is to provide a collapsible shelf organizer with a novel locking means which delivers superior structural integrity.",
"Yet another object of the present invention is to provide a collapsible, over-the-door shelf organizer having structural elements which comprise a unique locking means for ease of assembly.",
"These and other objects will be apparent from the present disclosure.",
"SUMMARY OF THE INVENTION The invention is a collapsible shelf organizer adapted for attachment to structures such as doors and the like.",
"It comprises at least two vertically extending frame members each having at least one basket support element equipped with a retainer and terminal loop structure.",
"The retainer of the basket support element can be a ball or sphere.",
"The shelf organizer further comprises at least one basket disposed between the vertically extending frame members.",
"Each basket has an upper surface, lower surface and means for locking with the retainer and terminal loop structure of each basket support element.",
"The shelf organizer further comprises a hanger bar having another means for locking with the upper and lower surfaces of the basket.",
"Each of the basket support elements operably connects to its vertically extending frame member so that the terminal loop structure of the basket support element is disposed along an axis extending substantially perpendicular to its specific vertically extending frame member.",
"The means for locking with the retainer and terminal loop structure of a basket support element comprises a grip lock and loop lock.",
"The grip lock is adapted for engagement with the retainer and the loop lock is adapted for engagement with the loop structure on the basket support element.",
"The basket is further comprised of a rear portion and mid portion, with the upper and lower surfaces of the basket being disposed on the rear portion, and the mid portion further comprising a superior surface and dorsal surface.",
"The upper and lower surfaces of the basket are adapted to engage the hanger bar.",
"The means for locking the hanger bar to the basket comprises a gravity lock and a flange lock.",
"The gravity lock further comprises a semi-circular piece and clasp portion, while the flange lock further comprises a semi-circular portion and lateral tip.",
"The semi-circular piece of the gravity lock is adapted for engagement with the dorsal surface of the mid portion of the basket, and the clasp portion of the gravity lock is adapted for engagement with the upper surface of the rear portion of the basket.",
"The semi-circular portion of the flange lock is adapted for engagement with the superior surface of the mid portion of the basket, and the lateral tip of the flange lock is adapted for engagement with the lower surface of the rear portion of the basket.",
"BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of this invention, reference is made to the following detailed description in connection with the accompanying drawings.",
"FIG. 1 is a lower perspective view of the collapsible shelf organizer showing the preferred embodiment of the present invention with a portion of a door from which it suspends represented by phantom lines.",
"FIG. 2 is an exploded view of the individual components which constitute the preferred embodiment of the present invention.",
"FIGS. 3 and 4 are lower perspective views of alternate design choices for the over-the-door shelf organizer.",
"FIG. 5 shows the component pieces of the shelf organizer illustrated in FIGS. 1 and 2 in its collapsed state and neatly packed in a configuration suitable for cost-effective shipping, storage and display.",
"FIGS. 6A through 6C are a series of drawings showing one aspect of the locking means of the present invention.",
"FIGS. 7A and 7B are isolated, cut-away views of another aspect of the locking mechanism of the present invention.",
"DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates the preferred embodiment of the present invention showing an assembled shelf organizer generally designated 10.",
"The preferred embodiment is constructed principally of coated steel wire, but one skilled in the art can readily appreciate a variety of other possible materials suitable for this construction.",
"FIG. 2 shows that shelf organizer 10 comprises two vertically extending frame members 20 and 20', basket 30 and hanger bar 31.",
"Vertical frame member 20, taken as representative, has circular member 28 at its uppermost portion.",
"Circular member 28 has in its diameter cross wire 29 for attachment to semi-circular end 16 of hanger bracket 15.",
"Extending from vertical frame member 20 is basket support element 21.",
"In the preferred embodiment shown in FIG. 2, support element 21 has a semi-circular shape with an upwardly facing concavity.",
"Other design variations are possible depending on the aesthetic qualities preferred, and all variations are within the scope and spirit of this disclosure.",
"Support element 21 extends orthogonally to the plane of frame member 20 and terminates in substantially closed loop structure 22 which extends from basket support element 21.",
"Basket 30 is comprised of front portion 34, mid portion 45 and rear portion 35.",
"At each of its two ends, front portion 34 has loop locks 32 and 32'",
"which are adapted for passage through, and releasable engagement with, the apertures formed in loop structures 22 and 22'.",
"Mid portion 45 is shown in FIG. 2 with superior surface 48 and dorsal surface 49.",
"Rear portion 35 has at each of its two ends grip locks 33 and 33'.",
"These locks are adapted for releasable engagement with frame members 20 and 20'",
"at ball retainers 23 and 23'.",
"Intermediate to grip lock 33 on rear portion 35 is lower surface 38.",
"Lower surface 38 (on rear portion 35) and superior surface 48 (on mid portion 45) cooperate to form a flange lock which is further described below.",
"Intermediate to grip lock 33'",
"on rear portion 35 is upper surface 39.",
"Upper surface 39 (on rear portion 35) and dorsal surface 49 (on mid portion 45) cooperate to form a gravity lock which is also described below.",
"Hanger bar 31 has at each of its two ends flange lock 36 and gravity lock 37, respectively.",
"Flange lock 36 is comprised of semi-circular portion 88 which straightens and terminates at lateral tip 68.",
"Gravity lock 37 is comprised of semi-circular piece 89 which straightens and terminates at clasp portion 69.",
"Semi-circular portion 88 and lateral tip 68 (of flange lock 36) are adapted for releasable engagement with superior surface 48 (on mid portion 45) and lower surface 38 (on rear portion 35).",
"Semi-circular piece 89 and clasp portion 69 (of gravity lock 37) are adapted for releasable engagement with dorsal surface 49 (on mid portion 45) and upper surface 39 (on rear portion 35).",
"Hanger bar 31 is shown in FIG. 2 with hooks 40 for hanging suitable items such as clothing and the like.",
"FIGS. 3 and 4 are lower perspective views of alternate style choices for the over-the-door shelf organizer and demonstrate that the number of hooks (40'",
"or 40") and their design configurations are a matter of practical and aesthetic choice.",
"FIG. 5 illustrates the components of the preferred shelf organizer (shown exploded in FIG. 2) in its collapsed state and packed in an optimum configuration for efficient shipping and storage.",
"The ability to knock down the component pieces avoids protrusions and allows the entire product to be shipped within a small and confined package represented by phantom lines.",
"FIGS. 6A, 6B and 6C sequentially show how hanger bar 31 is mounted to basket 30 during assembly.",
"FIG. 6A shows the initial placement of semi-circular portion 88 of flange lock 36 over superior surface 48 on mid portion 45, following the pathway designated with arrow X. Lateral tip 68 of flange lock 36 is then placed under lower surface 38 on rear portion 35, following the pathway designated with arrow Y. FIG. 6B shows that semi-circular piece 89 of gravity lock 37 is next placed above dorsal surface 49 on mid portion 45 and allowed to descend following the pathway designated with arrow Z. Lateral tip 68 of flange lock 36 snaps under rear portion 35 and engages lower surface 38 on rear portion 35.",
"FIG. 6C shows that flange lock 36 is biased into position by the cooperation of semi-circular portion 88 engaged to superior surface 48 of mid portion 45 and by lateral tip 68 engaged to lower surface 38 of rear portion 35.",
"The descending weight of basket 30 snaps semi-circular piece 89 of gravity lock 37 onto dorsal surface 49 on mid portion 45, and simultaneously snaps clasp portion 69 of gravity lock 37 onto upper surface 39 on rear portion 35, which completes the attachment of hanger bar 31 to basket 30.",
"FIGS. 7A and 7B are isolated, cut-away views of another aspect of the locking mechanism of the preferred embodiment.",
"FIG. 7A shows that basket 30 has loop lock 32 extending laterally from front portion 34.",
"Loop lock 32 is adapted to fit through the aperture formed by closed loop structure 22 of basket support element 21.",
"Forked grip lock 33 is adapted for slidable engagement with frame member 20 and comes to rest on ball retainer 23 to complete the lock as shown in FIG. 7B.",
"In overview, to assemble shelf organizer 10, hanger brackets 15 and 15'",
"(see FIG. 1) are placed over the top of a suitable structure such as a door.",
"Referring to FIGS. 1 and 2, cross wires 29 and 29'",
"on the upper portions of vertical frame members 20 and 20'",
"are slipped into semi-circular ends 16 and 16'",
"of hanger brackets 15 and 15'.",
"After spacing and centering suspended vertical frame members 20 and 20', basket 30 is placed between them and tipped forward so that rear portion 35 of basket 30 points in an upward direction as shown in FIG. 7A.",
"Loop lock 32 is inserted through loop structure 22 of frame member 20.",
"This is repeated on the opposite end of basket 30, with loop lock 32'",
"inserted through loop structure 22'",
"of frame member 20'",
"(not shown).",
"Once loop locks 32 and 32'",
"are in position, rear portion 35 of basket 30 is allowed to descend in a counter clockwise direction until grip lock 33 rests firmly on ball retainer 23 as shown in FIG. 7B.",
"This action is simultaneously conducted on the opposite end of basket 30, with loop locks 32 and 32'",
"rotating within loop structures 22 and 22'",
"until grip lock 33'",
"is firmly anchored on ball retainer 23'",
"(not shown).",
"Hanger 31 can be locked into basket 30 before or after vertical support frame members 20 and 20'",
"are locked with basket 30.",
"Further modifications based on this disclosure will occur to persons skilled in the art.",
"These modifications are within the scope and spirit of the present invention as defined by the following claims."
] |
RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional application Ser. No. 60/861,536, filed Nov. 28, 2006
FEDERALLY SPONSORED RESEARCH
[0002] Not Applicable
SEQUENCE LISTING
[0003] Not Applicable
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] The invention generally relates to gas concentrators, and more particularly relates to a concentrator having an integral system adapted for removing moisture from compressed gas feed stream to improve the performance efficiency of adsorbent beds. The application is particularly directed to compact; portable oxygen concentrators for therapeutic use, but the principles apply to any gas concentrator utilizing adsorbent beds.
[0006] 2. Description of the Related Art
[0007] The application of oxygen concentrators for therapeutic use is known, and many variants of such devices exist. A particularly useful class of oxygen concentrators is designed to be portable, allowing users to move about and to travel for extended periods of time without the need to carry a supply of stored oxygen. Most of these portable concentrators are based on Pressure Swing Adsorption (PSA) or Vacuum Pressure Swing Adsorption (VPSA) designs which feed compressed air to selective adsorption beds. In a typical oxygen concentrator, the beds selectively adsorb nitrogen, resulting in pressurized, oxygen-rich product gas.
[0008] The main elements in a typical oxygen concentrator are shown in FIG. 1 . Air is draw in, and typically filtered, at air inlet 1 before being pressurized by compressor 2 . The pressurized air is directed by a valve arrangement through adsorbent beds 3 . An exemplary adsorbent bed implementation, used in a concentrator design developed by the inventors, is three columns filled with zeolite powder. The pressurized air is directed through these columns in a series of steps which constitute a gas separation cycle, often a PSA cycle or some variation including vacuum instead of, or in conjunction with, compression. Although many different arrangements of beds are possible as well as a variety of different gas separation cycles, the result is that nitrogen is removed by the adsorbent material, and the resulting oxygen rich air is routed to a product gas storage device at 4 . Some of the oxygen rich air can be routed back through the bed to flush out (purge) the trapped nitrogen to an exhaust 6 . Generally multiple beds, or columns in the exemplary device, are used so at least one bed may be used to make product while at least one other is being purged, ensuring a continuous flow of product gas. The purged gas is exhausted from the concentrator at the exhaust 6 .
[0009] Such systems are known in the art, and it is appreciated that the gas flow control through the compressor and the beds in a gas separation cycle is complex and requires precise timing and control of parameters such as pressure, flow rate, and temperature to attain the desired oxygen concentration in the product gas stream. Accordingly, most modern concentrators also have a programmable controller 5 , typically a microprocessor, to monitor and control the details of the gas separation cycle and monitor various parameters. In particular, the controller controls the timing and operation of the various valves used to cycle the beds through feed and purge steps which make up the gas separation cycle. Also present in most portable concentrators is a conserver 7 which acts to ensure that oxygen rich gas is only delivered to a patient when a breath is inhaled. Thus less product gas is delivered than by means of a continuous flow arrangement, thereby allowing for smaller, lighter concentrator design. A pulse of oxygen rich air, called a bolus, is delivered in response to a detected breath via the conserver. A typical concentrator will also contain a user/data interface 8 .
[0010] A portable oxygen concentrator must be small, light and quiet to be useful, while retaining the capacity to produce a flow of product gas, usually a flow rate prescribed by a medical practitioner, adequate to provide for a patient's needs. Although fixed site PSA based concentrators have been available for many years, such fixed site units may weigh 50 pounds or more, be several cubic feet in size, and produce sound levels greater than 50 dBA. A portable concentrator may weigh on the order of 10 lbs, be less than one half cubic foot in size, and produce as little as 35-45 dbA. The portable concentrators still need to produce the prescribed flow rate of oxygen to be considered beneficial for therapeutic use. Thus portable concentrators involve a significant amount of miniaturization, leading to smaller, more complex designs compared to stationary units. System size, weight and complexity may lead to fewer mitigative options or design choices against contamination and other wear and tear effects.
[0011] One particular challenge of portable concentrator design is that the adsorbent beds must by necessity be small, yet capable of producing an adequate quantity of product gas. Since the adsorbent beds are optimized for maximum performance from a reduced size, any significant decrease in capacity of the beds over time can result in decreased product purity. One contributing factor that can lead to a decrease in bed capacity is the adsorption of impurities that do not completely desorb during normal process operation, leading to the accumulation and retention of impurities in the beds. An example of such an impurity that reduces the adsorption capacity of many zeolites used in air separation is water. Some stationary concentrators utilize some means of removing water from the compressed gas before feeding the adsorbent beds. Portable concentrators, by the nature of their application, are more likely to be exposed to a wide range of operating conditions including high humidity environments and/or rapid temperature changes that could result in the need for more sophisticated water rejection capabilities than implemented in prior designs. If water is present, either in the form of liquid or vapor, and enters the molecular sieve beds, the beds will irreversibly adsorb at least some of this water during each adsorption cycle. The energy of adsorption of water on zeolites is very high and not all water adsorbed during the adsorption steps in the process is desorbed during evacuation/purge of the beds under typical cycling. Therefore, complete removal of adsorbed water from zeolite beds usually entails applying some sort of energy to the beds, such as thermal, infrared, or microwave, and purging with a dry gas or applying a vacuum to the beds during the regeneration process. These regeneration processes are impractical in a portable concentrator. As a result, the accumulation of adsorbed water over time results in a reduction in capacity of the beds, as fewer sites are available for nitrogen binding. Fewer binding sites in the adsorbent bed can result in a decrease in product purity over time, and ultimately a shortened service life of the concentrator. Many zeolites used in air separation, and in particular advanced adsorbents, particularly the high lithium containing low silica X type zeolite, are hydrophilic in their activated state and can therefore be prone to this problem. In the drive to make more compact and efficient devices, cycle frequencies increase, and adsorbent productivity increases accordingly with advances in process and adsorbent technology. The corresponding decrease in adsorbent inventory exacerbates the problem as the amount of gas processed per unit of adsorbent increases proportionally and the presence of impurities in the process gas can deactivate the adsorbents at a much faster rate than with conventional PSA processes, as described in U.S. Pat. Nos. 7,037,358 and 7,160,367, which are incorporated by reference herein.
[0012] It is therefore desirable to keep moisture out of the sieve beds without detrimentally affecting other characteristics of the portable oxygen concentrator. Although highly effective air drying systems exist in other fields, most of these systems consume power, increase size and weight, or reduce system efficiency in a manner detrimental to the stringent power consumption, size/weight, and acoustic noise level requirements of portable concentrators. Using a single process bed with some portion of the bed dedicated to impurity processing/rejection is a common method of adding impurity rejection to a gas separation system. Adding beds dedicated to dehydration of the feed stream upstream of the zeolite beds or implementing layered adsorbent beds utilizing desiccants in addition to adsorbents suited for the desired gas fractionation are also common methods of adding water rejection capacity to a gas separation system, and can be effective in many circumstances. However, additional beds add significant size and weight to the concentrator, or in the case of layered beds the desiccant layer displaces volume that could otherwise be used for adsorbent used for highly efficient air separation or the volume of the process columns could be decreased accordingly, and additional power is used to compress gas through this desiccant. The desiccants typically used for pre-drying air are also prone to deactivation during constant cycling as well as during shutdown periods, and are often regenerated via applying one of the aforementioned methods. In some cases, the desiccant layer may be advantageous, but also might not be entirely effective at protecting the specialized adsorbents from water damage. By their nature, personal oxygen concentrators, be they portable or stationary, often operate in varied usage modalities rather than in the continuous duty manner of an industrial gas production plant. The duty cycle, storage time between use, and storage environment, can vary widely from unit to unit. For example, home health care providers may have a fleet of units that are stored in warehouses that are not climate controlled while waiting for delivery to patients for use. Similarly, patients may store units in their car or home for a given period of time without use depending on their individual oxygen needs. U.S. Pat. Nos. 7,037,358 and 7,160,367 teach that extreme care must be used in shutting down and storing PSA units that are run on an intermittent basis. Any water (or other impurities) remaining in the desiccant layer(s) or portion of the bed used for feed gas drying upon shutdown will diffuse over time due to the gradient in chemical potential between the portion of the bed that is used for impurity removal during normal operation and the dry portion of the beds. The diffusion coefficient of water in zeolites has an Ahrennius type temperature dependence, so if a concentrator is stored in a high temperature environment the rate of intraparticle diffusion will increase exponentially with temperature. The gas phase diffusion rate will increase with increasing temperature as well. The above referenced patents disclose many preventative measures that can be performed during shutdown and storage of PSA units that are operated intermittently to mitigate these issues. In an oxygen concentrator it is advantageous to remove as much water as possible from the compressed gas feed stream to prevent deactivation of the highly efficient zeolite, use less desiccant, and minimize the presence of water in the beds during shutdown. Traditional means of removing water such as coalescing filters and gravity water traps have limited abilities to remove water and can thereby limit the usable service life of oxygen concentrating equipment. The varying operating and storage environments that portable concentrators may be exposed to result in design challenges that more conventional gas separation systems such as gas separation plants might not encounter and must be addressed.
BRIEF SUMMARY OF THE INVENTION
[0013] A preferred embodiment of the present invention is a gas concentrator with a membrane dryer combined with the gas separation section to avoid efficiency and power loss, and still achieve the needed air drying. The novel concentrator utilizes the waste gas of the gas separation section to sweep the membrane dryer system. In this configuration, approximately 90% of the feed gas can be used as sweep, since only a small amount of product gas is taken for delivery to the patient. The integration of the gas separation cycle waste gas and the membrane air dryer also enables the sweep of the membrane to be dynamically controlled, if necessary to control water removal, since the sweep flow is not dictated by a fixed orifice in the membrane dryer housing, but rather by the controllable valve system of the pressure swing adsorption unit.
[0014] In another preferred embodiment, the invention provides an oxygen concentrator including a compressor, and a gas separation section including adsorbent for gas separation. The concentrator further includes a membrane dryer. Feed gas is routed from the compressor through inlet side of the dryer to the adsorbent. The dryer's sweep side is swept by the exhaust gas from the PSA or VPSA process.
[0015] In another embodiment, the invention provides a method of drying air in an oxygen concentrator. The method includes the steps of routing feed gas through an inlet filter, through the compressor, vacuum pump or combination vacuum and pressure pump, through the inlet side of a membrane dryer, and finally into an adsorption based gas separation system, and utilizing exhaust gas from the gas separation process to sweep the sweep side of the dryer.
[0016] In another embodiment, the concentrator may include a condenser and water trap utilized in combination with the membrane dryer disposed prior to the beds.
[0017] In another embodiment, the concentrator may include a specialized desiccant layer of adsorbent disposed before the high performance air separation adsorbent to further suppress the amount of water or other impurities, such as CO 2 , allowed to enter the adsorbent that is important to air separation.
[0018] In another embodiment, the concentrator may include a condenser and water trap utilized in combination with the membrane dryer and/or a specialized layer of adsorbent disposed before the high performance air separation adsorbent to further suppress the amount of water or other impurities, such as CO 2 allowed to enter the adsorbent that is important to air separation.
[0019] In one embodiment, the membrane dryer further acts as an exhaust muffler to decrease acoustic noise output from the concentrator. In another embodiment, the dew-point of the feed gas is monitored after the dryer, and the amount of sweep gas to the dryer is controlled to achieve a target dew-point level.
[0020] In another embodiment, the purge flow from the membrane dryer may be connected to the vacuum port of a pump in a VPSA system to enhance the pressure gradient across the membrane.
[0021] In another embodiment, the selectively permeable membrane may be designed to both transport water vapor and nitrogen gas selectively across the membrane where it is removed from the feed stream. The nitrogen depleted air would then enable more oxygen production from a given amount of sieve material than without the presence of a membrane dryer. Alternatively, this embodiment could result in smaller amounts of sieve material required for the adsorption separation process to reach a concentration suitable for therapeutic use. In another embodiment, the sweep gas from the exhaust is supplemented with a portion of the feed gas.
[0022] In another embodiment, the invention provides an oxygen concentrator including a compressor, and a gas separation section including a structured adsorbent system that increases the surface area of accessible zeolite beyond that achieved by conventional beaded adsorbents. The concentrator further includes a membrane dryer. Feed gas is routed from the compressor through the active portion of the dryer to the beds. The dryer's outer surface is swept by the exhaust gas from the beds.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The understanding of the following detailed description of certain preferred embodiments of the invention will be facilitated by referring to the accompanying figures.
[0024] FIG. 1 shows the general elements of gas concentrators as applicable to certain embodiments of the invention.
[0025] FIG. 2 illustrates the general operation of an exemplary membrane dryer.
[0026] FIG. 3 is a block diagram of a preferred embodiment of the invention.
[0027] FIG. 4 is a block diagram of another embodiment of a preferred embodiment of the invention.
[0028] FIG. 5 is a block diagram of another embodiment of the invention.
[0029] FIG. 6 shows an embodiment of the invention adding water removal to the beds
[0030] FIG. 7 shows a version of the invention, which utilizes multiple water rejection schemes.
[0031] FIG. 8 shows the dryer element simultaneously operating as noise muffler as well as dryer.
[0032] FIG. 9 shows an embodiment of the invention in a VPSA system
[0033] FIG. 10 shows an embodiment of the invention configured with a specially designed membrane that selectively transports both water and nitrogen across the membrane, but not oxygen.
[0034] FIG. 11 shows an embodiment of the invention with the addition of a structured adsorbent bed rather than the typical zeolite beads.
DETAILED DESCRIPTION OF THE INVENTION
[0035] Referring to FIG. 1 , general features of a gas concentrator are shown. Typically gas is drawn into the inlet through an inlet filter 1 into a compressor 2 . Compressed air is then delivered (through various filters and other devices) to a gas separation section for selectively adsorbing a component of the gas. The preferred embodiments of the invention, although applicable to a variety of gas concentrator implementations, will be described in detail for the case where the inlet gas is air, and the gas separation section is PSA, VSA, VPSA or some combination thereof, utilizing adsorbent beds 3 which selectively adsorb nitrogen, producing oxygen rich product.
[0036] A variety of gas separation section cycle types and bed arrangements are known in the art, most of which can benefit from the preferred embodiments of the invention. Whatever the details of the gas separation section 3 , typically product gas is accumulated in a storage device 4 . Storage devices may include a tank in the traditional sense, or may be some other device effective for holding a volume of gas, such as a tube, or some other volume filled with a high surface area-to-volume powder. Many modern concentrators used for therapeutic applications also include a programmable controller 5 to operate the concentrator and provide for user interface 8 and communications. Also typical are gas exhaust 6 , and delivery to patient, which often is through a conserver device 7 .
[0037] A problem with selective adsorbent bed technology, particularly when the adsorbing medium is a zeolite, is that the adsorbing medium may trap water vapor present in the feed gas due to the much higher energy levels required to desorb water than to desorb nitrogen (regeneration of saturated beds typically occurs at 300 degrees C. or greater). The trapped water can partially fill the sites available for nitrogen binding over time. This is a particularly serious problem for portable concentrators, which are generally designed without significant capacity margin to conserve size, weight, and power consumption. However, water retention in the adsorbing section is a problem for all concentrators which are fed by ambient air. Thus most concentrators utilize some method of at least partially drying the feed gas between the compressor and the beds, utilize a much larger than necessary adsorbent inventory, or have a short service interval to replace the adsorbent beds.
[0038] An oxygen concentrator designed by the inventors, for instance, uses a compressor and water trap arrangement, described in U.S. Pat. No. 7,066,985, which is incorporated by reference herein in its entirety. Such an arrangement is partially effective, and has the advantage that it does not negatively affect the efficiency of the concentrator, i.e., utilizing additional power or decreasing output to achieve the drying function. However, such efficient drying means have not been found to be completely effective for all uses, particularly when the concentrator is used in a humid environment or other conditions which do not promote condensation (and subsequent removal of liquid water from the feed stream) prior to moist air entering the beds. Thus, in some instances it has been found that the beds become saturated with water as a function of the number of cycles run and the operating environment, resulting in a capacity loss and a decrease in product purity proportional to the decreased capacity. Additionally, water remaining in the beds during shutdown periods or intermittent use will diffuse from the wet (feed) end of the bed towards the dry (product) end of the bed. In either case this effect may shorten the service life of the concentrator.
[0039] Other, more effective, drying systems exist that could be adapted to gas concentrators from other drying technologies, such as replaceable desiccant cartridges or refrigeration drying system, but due to most of these entailing increased power consumption, decreased product output, or increased service requirements, they have not to date been employed in portable gas concentrators.
[0040] One particularly effective means for removing water vapor from air is a membrane dryer. Membrane permeation is a technology adapted for drying compressed air systems. Membrane air dryers allow for substantial dew-point suppression of the compressed air stream through selective transport of water vapor through a hollow-core membrane fiber. The membranes can be engineered such that water vapor is allowed to permeate, while oxygen and nitrogen are not.
[0041] A membrane dryer is illustrated in FIG. 2 . The feed gas 10 is injected into the bore, or inlet side, of the hollow fiber 9 , where the water vapor is transported across the membrane to the outer surface, or sweep side, of the fiber. Some percentage of the dried compressed air, typically 5-50%, is used as a sweep 11 to drive the water vapor off the fiber surface to allow for continued transport of water from the bore of the hollow fiber to the outer surface. Although a cylindrical arrangement, with the inner area being the inlet side and the outer area being the sweep side, is used by way of example, other arrangements of inlet and sweep side geometries are known and should be considered within the scope of the invention.
[0042] In a portable oxygen concentrator, the power consumption must be kept to a minimum. Therefore, losing 5-50% of the product of the compressor system is not feasible, even though drying of the feed gas before the sieve beds is advantageous. However, an oxygen concentrator produces dry oxygen rich product, and creates nitrogen rich exhaust. Much of the exhaust gas is nearly as dry as the product gas. Although much of the moisture entering the device through the feed stream is being rejected upon the exhaust and purge portion of the adsorbent section cycle, the gas exiting the device is expanding which further enhances its dryness compared to the feed stream. Additionally the gas has a high velocity. This enables a novel approach to the application of membrane dryers in oxygen concentrators that effectively does not decrease the efficiency of the concentrator, yet substantially increases the service life and environmental ruggedness of the device.
[0043] As shown in FIG. 3 , the advantages of a membrane dryer can be combined with the gas separation section to avoid efficiency and power loss, but still achieve the needed air drying. The dryer 9 is placed between the compressor 2 and adsorbent beds 3 . Feed gas 10 is routed through the dryer active area 9 before delivery to the beds. The invention includes the novel idea of using the waste gas 11 of the gas separation section to sweep the membrane dryer system. In this configuration, approximately 90% of the gas input to the device can be used as sweep, since only a small amount of product gas is taken for delivery to the patient. Thus the sweep is gas that is exhausted anyway, so the dryer is swept with no effective loss of concentrator efficiency and substantially more airflow than would normally be available, since the exhaust gas is not parasitic to the input flow to the dryer.
[0044] The dew-point suppression of an integrated membrane air dryer and gas separation system could also be expanded to incorporate a staged water removal system. A simple staged system is shown in FIG. 4 , wherein a simple water filter 1 is added to the air inlet. Even a coarse filter could significantly reduce the load on the membrane dryer 9 . As shown in FIG. 5 , many concentrators already have some air drying capability. The figure shows the elements of the system described in U.S. Pat. No. 7,066,985, including condenser 12 and water trap 13 which operates by trapping liquid water in a gravity trap and using the high velocity waste gas to remove the liquid water from the system. Such additional water mitigation systems can be utilized in conjunction with a membrane dryer to achieve a desired dew-point of feed gas. A coalescing member or thermoelectric cooler combined with a liquid water trap/vent could be used to lower the temperature of the output gas from the compressor to force condensation and lower the dew-point of the gas as it travels through the air preparation system prior to entering the adsorbent beds. As shown in FIG. 6 , additional water mitigation systems could be used in conjunction with the membrane dryer, such as a layered bed using activated alumina, silica gel, or other desiccants to aid in any drying not accomplished in the membrane without compromising the zeolite bed. The addition of a desiccant to the beds can also be combined with a staged drying system, as shown in FIG. 7 . A combination of layered an un-layered beds could also be used.
[0045] In some implementations, the efficiency of the gas separation section might be improved and maintained longer due to the removal of water and other impurities from the feed gas stream of the gas separation section via the membrane since the feed gas would be depleted of impurities. This effect could be further improved by utilizing a shallow layer of specialty adsorbent at the feed end of the adsorbent bed that would have a greater capacity to remove water and regenerate much easier than the high lithium type X zeolites that are ideal for medical oxygen generation. The membrane and desiccant system can be designed to remove other trace impurities that would increase the productivity and recovery of the gas separation rather than simply extending the service life of the device.
[0046] Integration of the membrane air dryer and the portable oxygen concentrator may also yield improved noise reduction since the large body of the membrane air dryer could be designed as an integrated muffler as shown in FIG. 8 . By creating multifunctional volumes (dryer/muffler) the overall displacement volume of a portable oxygen concentrator can remain low while simultaneously improving overall system specifications.
[0047] In an embodiment of the invention where the gas separation section design includes a vacuum pump to reduce the low pressure to sub atmospheric levels (VPSA), the membrane dryer can be placed between the beds and the vacuum pump in the exhaust line to further improve the efficiency of the membrane dryer as depicted in FIG. 9 . Applying a vacuum to the sweep side of the membrane dryer is known in the art to increase the water transport capacity of the dryer as in U.S. Pat. No. 5,226,932, which is incorporated by reference in its entirety. By combining the advantages of the large volume fraction of sweep gas enabled by the membrane dryer and PSA integration along with the available vacuum levels present in a VPSA system, a drying system may be achieved where the dryer itself can be smaller than in other embodiments or the dew-point suppression of the dryer may be increased.
[0048] The art of selective membrane design has allowed the design of membranes that selectively transport just water or nitrogen or oxygen across the membrane while allowing the other constituents of the feed stream to remain unaffected. In a preferred embodiment the design of the membrane in the membrane drier might be designed to transport both water and nitrogen across the membrane to increase overall system efficiency as seen in FIG. 10 . In this case some portion of the nitrogen in the feed stream would be shunted directly into the waste stream of the gas separation section. Currently, generating high purity oxygen with just a selective membrane is difficult and not as efficient as using a PSA system, or the like, but with the combined advantages of both systems operating together, the overall design of the portable oxygen concentrator may be optimized.
[0049] The design advantages of using a structured adsorbent bed are known in the art of pressure swing adsorber design. These designs replace the more standard zeolite beads or powder with a zeolite structure, such as tubes made from zeolite crystal. Such designs can increase the surface area to volume ratio of the adsorbent far beyond the levels available in the typical zeolite beads. By increasing the surface area of the adsorber bed, the kinetics of adsorption and desorption are increased, allowing more cycles per minute and correspondingly more oxygen production per unit mass of zeolite when compared to zeolite beads. These structured bed designs may be particularly susceptible to water loading due to high volume of air passed through the small amount of adsorbent. As depicted in FIG. 11 , the invention of an integrated membrane dryer and gas separation system would be particularly advantageous to a system designed with a structured adsorbent bed or other fast-cycle implementations utilizing many adsorbent beds.
[0050] Although it is preferable to sweep the membrane dryer in a fashion that it is not parasitic to the feed stream to the gas separation section, in some cases, it may be desirable to supplement the sweep stream from the exhaust with a portion of the feed gas. Such an implementation could still be more efficient than using feed gas alone as the sweep.
[0051] The efficiency of the system may be further enhanced by monitoring the dew-point of the feed gas after the dryer. In this case the amount of sweep gas directed to the sweep side of the dryer can be controlled to achieve a target dew-point.
[0052] The foregoing description of the preferred embodiment of the present invention has shown, described and pointed out the fundamental novel features of the invention. It will be understood that various omissions, substitutions, and changes in the form of the detail of the apparatus as illustrated as well as the uses thereof, may be made by those skilled in the art, without departing from the spirit of the invention. Consequently, the scope of the invention should not be limited to the foregoing discussions, but should be defined by appended claims. | A feed gas drying system is described for a PSA or VPSA oxygen concentrator. A membrane dryer is inserted into the feed gas path to the concentrator absorbent beds, such that the moisture in the feed gas is directed to a part of the dryer exposed to the concentrator exhaust, thus achieving efficient operation of the membrane dryer with no loss of concentrator feed gas. | Briefly describe the main invention outlined in the provided context. | [
"RELATED APPLICATIONS [0001] This application claims priority to U.S. Provisional application Ser.",
"No. 60/861,536, filed Nov. 28, 2006 FEDERALLY SPONSORED RESEARCH [0002] Not Applicable SEQUENCE LISTING [0003] Not Applicable BACKGROUND OF THE INVENTION [0004] 1.",
"Field of the Invention [0005] The invention generally relates to gas concentrators, and more particularly relates to a concentrator having an integral system adapted for removing moisture from compressed gas feed stream to improve the performance efficiency of adsorbent beds.",
"The application is particularly directed to compact;",
"portable oxygen concentrators for therapeutic use, but the principles apply to any gas concentrator utilizing adsorbent beds.",
"[0006] 2.",
"Description of the Related Art [0007] The application of oxygen concentrators for therapeutic use is known, and many variants of such devices exist.",
"A particularly useful class of oxygen concentrators is designed to be portable, allowing users to move about and to travel for extended periods of time without the need to carry a supply of stored oxygen.",
"Most of these portable concentrators are based on Pressure Swing Adsorption (PSA) or Vacuum Pressure Swing Adsorption (VPSA) designs which feed compressed air to selective adsorption beds.",
"In a typical oxygen concentrator, the beds selectively adsorb nitrogen, resulting in pressurized, oxygen-rich product gas.",
"[0008] The main elements in a typical oxygen concentrator are shown in FIG. 1 .",
"Air is draw in, and typically filtered, at air inlet 1 before being pressurized by compressor 2 .",
"The pressurized air is directed by a valve arrangement through adsorbent beds 3 .",
"An exemplary adsorbent bed implementation, used in a concentrator design developed by the inventors, is three columns filled with zeolite powder.",
"The pressurized air is directed through these columns in a series of steps which constitute a gas separation cycle, often a PSA cycle or some variation including vacuum instead of, or in conjunction with, compression.",
"Although many different arrangements of beds are possible as well as a variety of different gas separation cycles, the result is that nitrogen is removed by the adsorbent material, and the resulting oxygen rich air is routed to a product gas storage device at 4 .",
"Some of the oxygen rich air can be routed back through the bed to flush out (purge) the trapped nitrogen to an exhaust 6 .",
"Generally multiple beds, or columns in the exemplary device, are used so at least one bed may be used to make product while at least one other is being purged, ensuring a continuous flow of product gas.",
"The purged gas is exhausted from the concentrator at the exhaust 6 .",
"[0009] Such systems are known in the art, and it is appreciated that the gas flow control through the compressor and the beds in a gas separation cycle is complex and requires precise timing and control of parameters such as pressure, flow rate, and temperature to attain the desired oxygen concentration in the product gas stream.",
"Accordingly, most modern concentrators also have a programmable controller 5 , typically a microprocessor, to monitor and control the details of the gas separation cycle and monitor various parameters.",
"In particular, the controller controls the timing and operation of the various valves used to cycle the beds through feed and purge steps which make up the gas separation cycle.",
"Also present in most portable concentrators is a conserver 7 which acts to ensure that oxygen rich gas is only delivered to a patient when a breath is inhaled.",
"Thus less product gas is delivered than by means of a continuous flow arrangement, thereby allowing for smaller, lighter concentrator design.",
"A pulse of oxygen rich air, called a bolus, is delivered in response to a detected breath via the conserver.",
"A typical concentrator will also contain a user/data interface 8 .",
"[0010] A portable oxygen concentrator must be small, light and quiet to be useful, while retaining the capacity to produce a flow of product gas, usually a flow rate prescribed by a medical practitioner, adequate to provide for a patient's needs.",
"Although fixed site PSA based concentrators have been available for many years, such fixed site units may weigh 50 pounds or more, be several cubic feet in size, and produce sound levels greater than 50 dBA.",
"A portable concentrator may weigh on the order of 10 lbs, be less than one half cubic foot in size, and produce as little as 35-45 dbA.",
"The portable concentrators still need to produce the prescribed flow rate of oxygen to be considered beneficial for therapeutic use.",
"Thus portable concentrators involve a significant amount of miniaturization, leading to smaller, more complex designs compared to stationary units.",
"System size, weight and complexity may lead to fewer mitigative options or design choices against contamination and other wear and tear effects.",
"[0011] One particular challenge of portable concentrator design is that the adsorbent beds must by necessity be small, yet capable of producing an adequate quantity of product gas.",
"Since the adsorbent beds are optimized for maximum performance from a reduced size, any significant decrease in capacity of the beds over time can result in decreased product purity.",
"One contributing factor that can lead to a decrease in bed capacity is the adsorption of impurities that do not completely desorb during normal process operation, leading to the accumulation and retention of impurities in the beds.",
"An example of such an impurity that reduces the adsorption capacity of many zeolites used in air separation is water.",
"Some stationary concentrators utilize some means of removing water from the compressed gas before feeding the adsorbent beds.",
"Portable concentrators, by the nature of their application, are more likely to be exposed to a wide range of operating conditions including high humidity environments and/or rapid temperature changes that could result in the need for more sophisticated water rejection capabilities than implemented in prior designs.",
"If water is present, either in the form of liquid or vapor, and enters the molecular sieve beds, the beds will irreversibly adsorb at least some of this water during each adsorption cycle.",
"The energy of adsorption of water on zeolites is very high and not all water adsorbed during the adsorption steps in the process is desorbed during evacuation/purge of the beds under typical cycling.",
"Therefore, complete removal of adsorbed water from zeolite beds usually entails applying some sort of energy to the beds, such as thermal, infrared, or microwave, and purging with a dry gas or applying a vacuum to the beds during the regeneration process.",
"These regeneration processes are impractical in a portable concentrator.",
"As a result, the accumulation of adsorbed water over time results in a reduction in capacity of the beds, as fewer sites are available for nitrogen binding.",
"Fewer binding sites in the adsorbent bed can result in a decrease in product purity over time, and ultimately a shortened service life of the concentrator.",
"Many zeolites used in air separation, and in particular advanced adsorbents, particularly the high lithium containing low silica X type zeolite, are hydrophilic in their activated state and can therefore be prone to this problem.",
"In the drive to make more compact and efficient devices, cycle frequencies increase, and adsorbent productivity increases accordingly with advances in process and adsorbent technology.",
"The corresponding decrease in adsorbent inventory exacerbates the problem as the amount of gas processed per unit of adsorbent increases proportionally and the presence of impurities in the process gas can deactivate the adsorbents at a much faster rate than with conventional PSA processes, as described in U.S. Pat. Nos. 7,037,358 and 7,160,367, which are incorporated by reference herein.",
"[0012] It is therefore desirable to keep moisture out of the sieve beds without detrimentally affecting other characteristics of the portable oxygen concentrator.",
"Although highly effective air drying systems exist in other fields, most of these systems consume power, increase size and weight, or reduce system efficiency in a manner detrimental to the stringent power consumption, size/weight, and acoustic noise level requirements of portable concentrators.",
"Using a single process bed with some portion of the bed dedicated to impurity processing/rejection is a common method of adding impurity rejection to a gas separation system.",
"Adding beds dedicated to dehydration of the feed stream upstream of the zeolite beds or implementing layered adsorbent beds utilizing desiccants in addition to adsorbents suited for the desired gas fractionation are also common methods of adding water rejection capacity to a gas separation system, and can be effective in many circumstances.",
"However, additional beds add significant size and weight to the concentrator, or in the case of layered beds the desiccant layer displaces volume that could otherwise be used for adsorbent used for highly efficient air separation or the volume of the process columns could be decreased accordingly, and additional power is used to compress gas through this desiccant.",
"The desiccants typically used for pre-drying air are also prone to deactivation during constant cycling as well as during shutdown periods, and are often regenerated via applying one of the aforementioned methods.",
"In some cases, the desiccant layer may be advantageous, but also might not be entirely effective at protecting the specialized adsorbents from water damage.",
"By their nature, personal oxygen concentrators, be they portable or stationary, often operate in varied usage modalities rather than in the continuous duty manner of an industrial gas production plant.",
"The duty cycle, storage time between use, and storage environment, can vary widely from unit to unit.",
"For example, home health care providers may have a fleet of units that are stored in warehouses that are not climate controlled while waiting for delivery to patients for use.",
"Similarly, patients may store units in their car or home for a given period of time without use depending on their individual oxygen needs.",
"U.S. Pat. Nos. 7,037,358 and 7,160,367 teach that extreme care must be used in shutting down and storing PSA units that are run on an intermittent basis.",
"Any water (or other impurities) remaining in the desiccant layer(s) or portion of the bed used for feed gas drying upon shutdown will diffuse over time due to the gradient in chemical potential between the portion of the bed that is used for impurity removal during normal operation and the dry portion of the beds.",
"The diffusion coefficient of water in zeolites has an Ahrennius type temperature dependence, so if a concentrator is stored in a high temperature environment the rate of intraparticle diffusion will increase exponentially with temperature.",
"The gas phase diffusion rate will increase with increasing temperature as well.",
"The above referenced patents disclose many preventative measures that can be performed during shutdown and storage of PSA units that are operated intermittently to mitigate these issues.",
"In an oxygen concentrator it is advantageous to remove as much water as possible from the compressed gas feed stream to prevent deactivation of the highly efficient zeolite, use less desiccant, and minimize the presence of water in the beds during shutdown.",
"Traditional means of removing water such as coalescing filters and gravity water traps have limited abilities to remove water and can thereby limit the usable service life of oxygen concentrating equipment.",
"The varying operating and storage environments that portable concentrators may be exposed to result in design challenges that more conventional gas separation systems such as gas separation plants might not encounter and must be addressed.",
"BRIEF SUMMARY OF THE INVENTION [0013] A preferred embodiment of the present invention is a gas concentrator with a membrane dryer combined with the gas separation section to avoid efficiency and power loss, and still achieve the needed air drying.",
"The novel concentrator utilizes the waste gas of the gas separation section to sweep the membrane dryer system.",
"In this configuration, approximately 90% of the feed gas can be used as sweep, since only a small amount of product gas is taken for delivery to the patient.",
"The integration of the gas separation cycle waste gas and the membrane air dryer also enables the sweep of the membrane to be dynamically controlled, if necessary to control water removal, since the sweep flow is not dictated by a fixed orifice in the membrane dryer housing, but rather by the controllable valve system of the pressure swing adsorption unit.",
"[0014] In another preferred embodiment, the invention provides an oxygen concentrator including a compressor, and a gas separation section including adsorbent for gas separation.",
"The concentrator further includes a membrane dryer.",
"Feed gas is routed from the compressor through inlet side of the dryer to the adsorbent.",
"The dryer's sweep side is swept by the exhaust gas from the PSA or VPSA process.",
"[0015] In another embodiment, the invention provides a method of drying air in an oxygen concentrator.",
"The method includes the steps of routing feed gas through an inlet filter, through the compressor, vacuum pump or combination vacuum and pressure pump, through the inlet side of a membrane dryer, and finally into an adsorption based gas separation system, and utilizing exhaust gas from the gas separation process to sweep the sweep side of the dryer.",
"[0016] In another embodiment, the concentrator may include a condenser and water trap utilized in combination with the membrane dryer disposed prior to the beds.",
"[0017] In another embodiment, the concentrator may include a specialized desiccant layer of adsorbent disposed before the high performance air separation adsorbent to further suppress the amount of water or other impurities, such as CO 2 , allowed to enter the adsorbent that is important to air separation.",
"[0018] In another embodiment, the concentrator may include a condenser and water trap utilized in combination with the membrane dryer and/or a specialized layer of adsorbent disposed before the high performance air separation adsorbent to further suppress the amount of water or other impurities, such as CO 2 allowed to enter the adsorbent that is important to air separation.",
"[0019] In one embodiment, the membrane dryer further acts as an exhaust muffler to decrease acoustic noise output from the concentrator.",
"In another embodiment, the dew-point of the feed gas is monitored after the dryer, and the amount of sweep gas to the dryer is controlled to achieve a target dew-point level.",
"[0020] In another embodiment, the purge flow from the membrane dryer may be connected to the vacuum port of a pump in a VPSA system to enhance the pressure gradient across the membrane.",
"[0021] In another embodiment, the selectively permeable membrane may be designed to both transport water vapor and nitrogen gas selectively across the membrane where it is removed from the feed stream.",
"The nitrogen depleted air would then enable more oxygen production from a given amount of sieve material than without the presence of a membrane dryer.",
"Alternatively, this embodiment could result in smaller amounts of sieve material required for the adsorption separation process to reach a concentration suitable for therapeutic use.",
"In another embodiment, the sweep gas from the exhaust is supplemented with a portion of the feed gas.",
"[0022] In another embodiment, the invention provides an oxygen concentrator including a compressor, and a gas separation section including a structured adsorbent system that increases the surface area of accessible zeolite beyond that achieved by conventional beaded adsorbents.",
"The concentrator further includes a membrane dryer.",
"Feed gas is routed from the compressor through the active portion of the dryer to the beds.",
"The dryer's outer surface is swept by the exhaust gas from the beds.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0023] The understanding of the following detailed description of certain preferred embodiments of the invention will be facilitated by referring to the accompanying figures.",
"[0024] FIG. 1 shows the general elements of gas concentrators as applicable to certain embodiments of the invention.",
"[0025] FIG. 2 illustrates the general operation of an exemplary membrane dryer.",
"[0026] FIG. 3 is a block diagram of a preferred embodiment of the invention.",
"[0027] FIG. 4 is a block diagram of another embodiment of a preferred embodiment of the invention.",
"[0028] FIG. 5 is a block diagram of another embodiment of the invention.",
"[0029] FIG. 6 shows an embodiment of the invention adding water removal to the beds [0030] FIG. 7 shows a version of the invention, which utilizes multiple water rejection schemes.",
"[0031] FIG. 8 shows the dryer element simultaneously operating as noise muffler as well as dryer.",
"[0032] FIG. 9 shows an embodiment of the invention in a VPSA system [0033] FIG. 10 shows an embodiment of the invention configured with a specially designed membrane that selectively transports both water and nitrogen across the membrane, but not oxygen.",
"[0034] FIG. 11 shows an embodiment of the invention with the addition of a structured adsorbent bed rather than the typical zeolite beads.",
"DETAILED DESCRIPTION OF THE INVENTION [0035] Referring to FIG. 1 , general features of a gas concentrator are shown.",
"Typically gas is drawn into the inlet through an inlet filter 1 into a compressor 2 .",
"Compressed air is then delivered (through various filters and other devices) to a gas separation section for selectively adsorbing a component of the gas.",
"The preferred embodiments of the invention, although applicable to a variety of gas concentrator implementations, will be described in detail for the case where the inlet gas is air, and the gas separation section is PSA, VSA, VPSA or some combination thereof, utilizing adsorbent beds 3 which selectively adsorb nitrogen, producing oxygen rich product.",
"[0036] A variety of gas separation section cycle types and bed arrangements are known in the art, most of which can benefit from the preferred embodiments of the invention.",
"Whatever the details of the gas separation section 3 , typically product gas is accumulated in a storage device 4 .",
"Storage devices may include a tank in the traditional sense, or may be some other device effective for holding a volume of gas, such as a tube, or some other volume filled with a high surface area-to-volume powder.",
"Many modern concentrators used for therapeutic applications also include a programmable controller 5 to operate the concentrator and provide for user interface 8 and communications.",
"Also typical are gas exhaust 6 , and delivery to patient, which often is through a conserver device 7 .",
"[0037] A problem with selective adsorbent bed technology, particularly when the adsorbing medium is a zeolite, is that the adsorbing medium may trap water vapor present in the feed gas due to the much higher energy levels required to desorb water than to desorb nitrogen (regeneration of saturated beds typically occurs at 300 degrees C. or greater).",
"The trapped water can partially fill the sites available for nitrogen binding over time.",
"This is a particularly serious problem for portable concentrators, which are generally designed without significant capacity margin to conserve size, weight, and power consumption.",
"However, water retention in the adsorbing section is a problem for all concentrators which are fed by ambient air.",
"Thus most concentrators utilize some method of at least partially drying the feed gas between the compressor and the beds, utilize a much larger than necessary adsorbent inventory, or have a short service interval to replace the adsorbent beds.",
"[0038] An oxygen concentrator designed by the inventors, for instance, uses a compressor and water trap arrangement, described in U.S. Pat. No. 7,066,985, which is incorporated by reference herein in its entirety.",
"Such an arrangement is partially effective, and has the advantage that it does not negatively affect the efficiency of the concentrator, i.e., utilizing additional power or decreasing output to achieve the drying function.",
"However, such efficient drying means have not been found to be completely effective for all uses, particularly when the concentrator is used in a humid environment or other conditions which do not promote condensation (and subsequent removal of liquid water from the feed stream) prior to moist air entering the beds.",
"Thus, in some instances it has been found that the beds become saturated with water as a function of the number of cycles run and the operating environment, resulting in a capacity loss and a decrease in product purity proportional to the decreased capacity.",
"Additionally, water remaining in the beds during shutdown periods or intermittent use will diffuse from the wet (feed) end of the bed towards the dry (product) end of the bed.",
"In either case this effect may shorten the service life of the concentrator.",
"[0039] Other, more effective, drying systems exist that could be adapted to gas concentrators from other drying technologies, such as replaceable desiccant cartridges or refrigeration drying system, but due to most of these entailing increased power consumption, decreased product output, or increased service requirements, they have not to date been employed in portable gas concentrators.",
"[0040] One particularly effective means for removing water vapor from air is a membrane dryer.",
"Membrane permeation is a technology adapted for drying compressed air systems.",
"Membrane air dryers allow for substantial dew-point suppression of the compressed air stream through selective transport of water vapor through a hollow-core membrane fiber.",
"The membranes can be engineered such that water vapor is allowed to permeate, while oxygen and nitrogen are not.",
"[0041] A membrane dryer is illustrated in FIG. 2 .",
"The feed gas 10 is injected into the bore, or inlet side, of the hollow fiber 9 , where the water vapor is transported across the membrane to the outer surface, or sweep side, of the fiber.",
"Some percentage of the dried compressed air, typically 5-50%, is used as a sweep 11 to drive the water vapor off the fiber surface to allow for continued transport of water from the bore of the hollow fiber to the outer surface.",
"Although a cylindrical arrangement, with the inner area being the inlet side and the outer area being the sweep side, is used by way of example, other arrangements of inlet and sweep side geometries are known and should be considered within the scope of the invention.",
"[0042] In a portable oxygen concentrator, the power consumption must be kept to a minimum.",
"Therefore, losing 5-50% of the product of the compressor system is not feasible, even though drying of the feed gas before the sieve beds is advantageous.",
"However, an oxygen concentrator produces dry oxygen rich product, and creates nitrogen rich exhaust.",
"Much of the exhaust gas is nearly as dry as the product gas.",
"Although much of the moisture entering the device through the feed stream is being rejected upon the exhaust and purge portion of the adsorbent section cycle, the gas exiting the device is expanding which further enhances its dryness compared to the feed stream.",
"Additionally the gas has a high velocity.",
"This enables a novel approach to the application of membrane dryers in oxygen concentrators that effectively does not decrease the efficiency of the concentrator, yet substantially increases the service life and environmental ruggedness of the device.",
"[0043] As shown in FIG. 3 , the advantages of a membrane dryer can be combined with the gas separation section to avoid efficiency and power loss, but still achieve the needed air drying.",
"The dryer 9 is placed between the compressor 2 and adsorbent beds 3 .",
"Feed gas 10 is routed through the dryer active area 9 before delivery to the beds.",
"The invention includes the novel idea of using the waste gas 11 of the gas separation section to sweep the membrane dryer system.",
"In this configuration, approximately 90% of the gas input to the device can be used as sweep, since only a small amount of product gas is taken for delivery to the patient.",
"Thus the sweep is gas that is exhausted anyway, so the dryer is swept with no effective loss of concentrator efficiency and substantially more airflow than would normally be available, since the exhaust gas is not parasitic to the input flow to the dryer.",
"[0044] The dew-point suppression of an integrated membrane air dryer and gas separation system could also be expanded to incorporate a staged water removal system.",
"A simple staged system is shown in FIG. 4 , wherein a simple water filter 1 is added to the air inlet.",
"Even a coarse filter could significantly reduce the load on the membrane dryer 9 .",
"As shown in FIG. 5 , many concentrators already have some air drying capability.",
"The figure shows the elements of the system described in U.S. Pat. No. 7,066,985, including condenser 12 and water trap 13 which operates by trapping liquid water in a gravity trap and using the high velocity waste gas to remove the liquid water from the system.",
"Such additional water mitigation systems can be utilized in conjunction with a membrane dryer to achieve a desired dew-point of feed gas.",
"A coalescing member or thermoelectric cooler combined with a liquid water trap/vent could be used to lower the temperature of the output gas from the compressor to force condensation and lower the dew-point of the gas as it travels through the air preparation system prior to entering the adsorbent beds.",
"As shown in FIG. 6 , additional water mitigation systems could be used in conjunction with the membrane dryer, such as a layered bed using activated alumina, silica gel, or other desiccants to aid in any drying not accomplished in the membrane without compromising the zeolite bed.",
"The addition of a desiccant to the beds can also be combined with a staged drying system, as shown in FIG. 7 .",
"A combination of layered an un-layered beds could also be used.",
"[0045] In some implementations, the efficiency of the gas separation section might be improved and maintained longer due to the removal of water and other impurities from the feed gas stream of the gas separation section via the membrane since the feed gas would be depleted of impurities.",
"This effect could be further improved by utilizing a shallow layer of specialty adsorbent at the feed end of the adsorbent bed that would have a greater capacity to remove water and regenerate much easier than the high lithium type X zeolites that are ideal for medical oxygen generation.",
"The membrane and desiccant system can be designed to remove other trace impurities that would increase the productivity and recovery of the gas separation rather than simply extending the service life of the device.",
"[0046] Integration of the membrane air dryer and the portable oxygen concentrator may also yield improved noise reduction since the large body of the membrane air dryer could be designed as an integrated muffler as shown in FIG. 8 .",
"By creating multifunctional volumes (dryer/muffler) the overall displacement volume of a portable oxygen concentrator can remain low while simultaneously improving overall system specifications.",
"[0047] In an embodiment of the invention where the gas separation section design includes a vacuum pump to reduce the low pressure to sub atmospheric levels (VPSA), the membrane dryer can be placed between the beds and the vacuum pump in the exhaust line to further improve the efficiency of the membrane dryer as depicted in FIG. 9 .",
"Applying a vacuum to the sweep side of the membrane dryer is known in the art to increase the water transport capacity of the dryer as in U.S. Pat. No. 5,226,932, which is incorporated by reference in its entirety.",
"By combining the advantages of the large volume fraction of sweep gas enabled by the membrane dryer and PSA integration along with the available vacuum levels present in a VPSA system, a drying system may be achieved where the dryer itself can be smaller than in other embodiments or the dew-point suppression of the dryer may be increased.",
"[0048] The art of selective membrane design has allowed the design of membranes that selectively transport just water or nitrogen or oxygen across the membrane while allowing the other constituents of the feed stream to remain unaffected.",
"In a preferred embodiment the design of the membrane in the membrane drier might be designed to transport both water and nitrogen across the membrane to increase overall system efficiency as seen in FIG. 10 .",
"In this case some portion of the nitrogen in the feed stream would be shunted directly into the waste stream of the gas separation section.",
"Currently, generating high purity oxygen with just a selective membrane is difficult and not as efficient as using a PSA system, or the like, but with the combined advantages of both systems operating together, the overall design of the portable oxygen concentrator may be optimized.",
"[0049] The design advantages of using a structured adsorbent bed are known in the art of pressure swing adsorber design.",
"These designs replace the more standard zeolite beads or powder with a zeolite structure, such as tubes made from zeolite crystal.",
"Such designs can increase the surface area to volume ratio of the adsorbent far beyond the levels available in the typical zeolite beads.",
"By increasing the surface area of the adsorber bed, the kinetics of adsorption and desorption are increased, allowing more cycles per minute and correspondingly more oxygen production per unit mass of zeolite when compared to zeolite beads.",
"These structured bed designs may be particularly susceptible to water loading due to high volume of air passed through the small amount of adsorbent.",
"As depicted in FIG. 11 , the invention of an integrated membrane dryer and gas separation system would be particularly advantageous to a system designed with a structured adsorbent bed or other fast-cycle implementations utilizing many adsorbent beds.",
"[0050] Although it is preferable to sweep the membrane dryer in a fashion that it is not parasitic to the feed stream to the gas separation section, in some cases, it may be desirable to supplement the sweep stream from the exhaust with a portion of the feed gas.",
"Such an implementation could still be more efficient than using feed gas alone as the sweep.",
"[0051] The efficiency of the system may be further enhanced by monitoring the dew-point of the feed gas after the dryer.",
"In this case the amount of sweep gas directed to the sweep side of the dryer can be controlled to achieve a target dew-point.",
"[0052] The foregoing description of the preferred embodiment of the present invention has shown, described and pointed out the fundamental novel features of the invention.",
"It will be understood that various omissions, substitutions, and changes in the form of the detail of the apparatus as illustrated as well as the uses thereof, may be made by those skilled in the art, without departing from the spirit of the invention.",
"Consequently, the scope of the invention should not be limited to the foregoing discussions, but should be defined by appended claims."
] |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. patent application Ser. No. 11/195,361, filed Aug. 1, 2005, now pending, which claims priority from Korean Patent Application No. 2004-60188, filed Jul. 30, 2004, the contents of which are hereby incorporated by reference in their entirety for all purposes.
BACKGROUND
[0002] 1. Technical Field
[0003] This disclosure relates generally to an interconnection structure of an integrated circuit (IC) chip and, more particularly, to a structure associated with an input/output (I/O) pad having increased contact area with an electroless nickel plating layer.
[0004] 2. Description of the Related Art
[0005] Flip chip bonding technology and wafer level packaging technology may employ metal bumps which are distributed over a surface of the IC chip. Such distribution of bump locations may provide several advantages of smaller package size, higher mounting density, improved electrical properties, etc. in comparison with conventional interconnection and packaging technologies.
[0006] Typically, the metal bumps are formed on respective I/O pads exposed at the chip surface. The I/O pads are chip terminals that allow signal/power access to and from chip internal circuitry. While the metal bumps may be made of mainly solder, the I/O pads may be made of aluminum or copper. Connections between the metal bump and the I/O pad may require under bump metal (UBM) layers. The UBM layers may act as an adhesive layer, a diffusion barrier, a plating base, and a solder wetting layer.
[0007] As well known in the art, the UBM layers may be composed of one or more layers and are formed through a complicated process. To form the UBM layers, several metals are deposited in sequence by sputtering, for example, which are then covered with photoresist material. The photoresist material is selectively removed by exposure and development, thus producing a desired photoresist pattern. Then bump metal is deposited using electroplating, for example, on the pre-deposited UBM metals through the photoresist pattern. After the photoresist pattern is completely removed, the UBM metals are etched using the bump metal as an etch mask. These complicated processes may incur increases in time and cost.
[0008] Electroless plating techniques, or electroplating, can uniformly and simply form a plating layer by dipping an object to be plated in a bath containing an appropriate chemical solution. Through an electrolysis process, products from the chemical solution are selectively deposited on the UBM layers on the I/O pads, thus eliminating the need for photoresist material, related processes, and etching of the UBM layers.
[0009] FIG. 1 is a sectional diagram illustrating a conventional interconnection structure of an IC chip. Referring to FIG. 1 , the IC chip 10 has a tungsten pad 11 disposed on an upper portion of the chip. The tungsten pad 11 is a terminal for internal chip circuitry. An I/O pad 12 is formed of aluminum or copper on the tungsten pad 11 . A top surface of the IC chip 10 is covered with a passivation layer 13 and a polymer layer 14 for protecting the chip internal circuitry. The I/O pad 12 is exposed through the passivation layer 13 and the polymer layer 14 .
[0010] Minute zinc particles 15 are formed on the I/O pad 12 using a zincating, or zinc immersion, technique. The zinc particles 15 may act as a plating core during electroless plating. A surface of the I/O pad 12 is coated with a nickel layer 16 through chemical reduction. A ball-shaped solder bump 17 is formed on the nickel layer 16 acting as the UBM layer.
[0011] In this conventional interconnection structure, a contact area between the I/O pad 12 and the electroless nickel plating layer 16 is relatively small. For example, the diameter of the circular-shaped nickel layer 16 is about 135 μm. However, the diameter or width of the I/O pad 12 is about 70 μm, and further, an exposed part of the I/O pad 12 is only about 50 μm in diameter. This may cause a difference between the size of the I/O pad 12 allowed at the chip level and the size of the plating layer 16 required at the package level.
[0012] Since the contact area between the I/O pad 12 and the plating layer 16 is limited to the exposed part of the I/O pad 12 , metallic joints between both metal layers 12 and 16 may often be unsatisfactory. Therefore, when the metallic joints are subjected to thermally inducted stress, cracks or delaminations may occur in the metallic joints, which raises concerns regarding yield and reliability.
[0013] Embodiments of the invention address these and other disadvantages of the conventional art.
SUMMARY
[0014] Embodiments of the invention provide an interconnection structure for an integrated circuit (IC) chip in which the connections between metallic input/output (I/O) pads and metallic plating layers are strengthened.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a sectional diagram illustrating a conventional interconnection structure of an IC chip.
[0016] FIG. 2 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with some embodiments of the invention.
[0017] FIGS. 3A to 3 E are sectional diagrams illustrating a sequence of exemplary processes for forming the interconnection structure of FIG. 2 .
[0018] FIG. 4 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with some other embodiments of the invention.
[0019] FIG. 5 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with more embodiments of the invention.
[0020] FIG. 6 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with different embodiments of the invention.
DETAILED DESCRIPTION
[0021] Exemplary, non-limiting embodiments of the invention are described more fully below with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, the disclosed embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the teachings of the invention to those skilled in the art. As will be recognized by those of skill in the art, the teachings of this invention may be employed in varied and numerous embodiments without departing from said teachings.
[0022] To avoid unnecessarily obscuring the inventive aspects of the exemplary embodiments, well-known structures and processes may not be described or illustrated in detail. Furthermore, for simplicity and clarity of illustration, the figures are not drawn to scale. Rather, the dimensions of some of the elements are exaggerated relative to other elements. Throughout the drawings, like reference numerals are used to indicate similar parts. Furthermore, it should be recognized that the structure illustrated in the following figures, which shows only one small part of an IC chip, my be repeated over the entire IC chip and similarly, over a whole wafer.
[0023] FIG. 2 is a sectional diagram illustrating an interconnection structure of an IC chip 20 in accordance with some embodiments of the invention. A tungsten pad 21 is disposed on an upper portion of the IC chip 20 . The IC chip 20 has internal circuitry (not shown), and the tungsten pad 21 is provided as a terminal for internal chip circuitry. The tungsten pad 21 may be formed of some other suitable material besides tungsten. The IC chip 20 may be a memory device such as DRAM, SRAM, or flash memory, or it may be a non-memory device such as a logic device.
[0024] A top surface of the IC chip 20 is covered with a passivation layer 22 . The passivation layer 22 provides protection to the chip internal circuitry and may be formed of silicon nitride or silicon oxide. A polymer layer 23 covers the passivation layer 22 . The polymer layer 23 may be formed of polyimide, for example, and provides electrical isolation, protection, and stress dispersion. The tungsten pad 21 is exposed through the passivation layer 22 and the polymer layer 23 .
[0025] An I/O pad 26 is disposed above the tungsten pad 21 and extends to a top surface of the polymer layer 23 . That is, a central portion of the I/O pad 26 is in contact with the tungsten pad 21 , and a peripheral portion of the I/O pad 26 is in contact with the polymer layer 23 around the tungsten pad 21 . The I/O pad 26 may be formed of aluminum or copper. Minute zinc particles 27 are formed on the I/O pad 26 using a zinc immersion, or zincating, technique. The zinc particles 27 may act as a plating core during a subsequent electroless plating process.
[0026] In the electroless plating process, a surface of the I/O pad 26 is coated with a suitable plating layer 28 through chemical reduction. The electroless plating layer 28 may be formed of nickel and acts as the UBM layer. Phosphorus or boron may be added to the nickel, and a gold layer may be deposited on the nickel layer. A metal bump 29 , such as a ball-shaped solder bump, may be formed on the electroless plating layer 28 .
[0027] As discussed above, the I/O pad 26 that extends to the top surface of the polymer layer 23 may satisfy the size requirement of the package level. In comparison with the aforementioned conventional structure, an exposed part of the tungsten pad 21 may remain about 50 μm in diameter. However, the diameter of the I/O pad 26 may approximate 135 μm, which is substantially equal to that of the electroless plating layer 28 . As a result, the contact area between the I/O pad 26 and the electroless plating layer 28 is increased about 7.3 times compared to the conventional structure.
[0028] FIGS. 3A to 3 E are sectional diagrams illustrating a sequence of exemplary processes for forming the interconnection structure of FIG. 2 .
[0029] Referring to FIG. 3A , the tungsten pad 21 is formed on the upper portion of the IC chip 20 during a wafer fabrication process. The tungsten pad 21 is provided as a terminal of the chip internal circuitry. The passivation layer 22 and the polymer layer 23 are deposited in sequence on the top surface of the IC chip 20 , providing protection, electrical isolation, and stress dispersion.
[0030] The passivation layer 22 may be formed of silicon nitride or silicon oxide, and the polymer layer 23 may be formed of polyimide, epoxy, benzo-cyclo-butene (BCB), or other suitable polymeric material. Portions of the passivation layer 22 and the polymer layer 23 are removed to selectively expose the tungsten pad 21 to the outside. Layer deposition and selective removal processes are well known in this art, and therefore a detailed description of the same is omitted. Furthermore, it will be appreciated that such processes may be performed simultaneously on the whole wafer.
[0031] Referring to FIG. 3B , a pad metal layer 24 may be deposited over all exposed surfaces on the wafer. The pad metal layer 24 may be formed of aluminum, copper, or another suitable conductive material. The pad metal layer 24 may be deposited using a physical vapor deposition (PVD) process, such as sputtering. The thickness of the pad metal layer 24 may be about 8000 Å.
[0032] Referring to FIG. 3C , a photoresist pattern 25 is provided on the pad metal layer 24 around the tungsten pad 21 . As is well known, a photoresist material that is coated, selectively exposed, and developed may be used to form the photoresist pattern 25 . The pad metal layer 24 is selectively etched using the photoresist pattern 25 as an etch mask. The pad metal layer remains only under the photoresist pattern 25 , thus forming the I/O pad 26 .
[0033] Referring to FIG. 3D , the photoresist pattern 25 is completely removed, and thereby the I/O pad 26 is exposed to the outside. Next, zinc particles 27 are formed on the I/O pad 26 using a zincating technique that employs a zincate solution. Since zincating techniques are well known in the art, a detailed description of the same is omitted. Although the size of the zinc particles 27 are exaggerated for clarity, in reality the size of the zinc particles 27 may be negligible. The zinc particles 27 may act as a plating core that may promote combination of the I/O pad 26 and plating material during a subsequent electroless plating process.
[0034] Referring to FIG. 3E , after the zinc particles 27 are formed, the electroless plating layer 28 is deposited on the I/O pad 26 through chemical reduction by an electroless plating process. The electroless plating layer 28 may be formed of nickel, phosphorus-added nickel, or boron-added nickel. After deposition of the nickel layer 28 , a gold layer may be deposited thereon to prevent oxidation. The electroless nickel layer 28 may have a thickness of several microns (μm), and the gold layer may have a thickness of about 0.1 μm.
[0035] In alternative embodiments, the I/O pad 26 may be formed between the passivation layer 22 and the polymer layer 23 .
[0036] FIG. 4 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with some other embodiments of the invention.
[0037] Referring to FIG. 4 , the I/O pad 26 is formed just after the passivation layer 22 is formed on the top surface of the IC chip 20 . The I/O pad 26 has a central portion in contact with the tungsten pad 21 , and a peripheral portion in contact with the passivation layer 22 around the tungsten pad 21 . The I/O pad 26 may be formed through the same processes as those described above for FIGS. 3A-3E .
[0038] The polymer layer 23 is coated on the whole wafer including the I/O pad 26 , and then a portion of the polymer layer 23 is removed to expose the I/O pad 26 . An exposed area of the I/O pad 26 is greater than the area of the I/O pad that is contact with the tungsten pad 21 . The zinc particles 27 are formed on the I/O pad 26 , and then the electroless plating layer 28 is deposited thereon.
[0039] In the embodiments described above, the solder bump 29 is disposed at approximately the same location, that is, above the tungsten pad 21 . In alternative embodiments, the solder bump 29 may be disposed at other locations that are separated from the tungsten pad 21 .
[0040] FIG. 5 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with more embodiments of the invention.
[0041] Referring to FIG. 5 , the I/O pad 26 not only acts as a normal pad on which the solder bump 29 is mounted, but also functions as a typical redistribution or rerouting line. A first portion of the I/O pad 26 is placed on the tungsten pad 21 , and a second portion of the I/O pad 26 is extended along the top surface of the polymer layer 23 to the solder bump 29 . Altering the photoresist pattern 25 shown in FIG. 3C may form this structure of the I/O pad 26 used as a redistribution line.
[0042] Such a structure may further include an upper additional polymer layer 30 . Alternatively, the I/O pad 26 used as a redistribution line may be disposed between the passivation layer 22 and the polymer layer 23 .
[0043] According to embodiments of the invention, the I/O pad 26 may also act as a test pad.
[0044] FIG. 6 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with different embodiments of the invention.
[0045] Referring to FIG. 6 , one portion of the I/O pad 26 is extended along the top surface of the passivation layer 22 . After the wafer fabrication process, the IC chip 20 may undergo an electrical die sorting (EDS) test. In the EDS test, a test probe 31 is typically contacted with the I/O pad 26 so as to implement electrical tests. However, this may cause damage to the I/O pad 26 . A separate pad 26 a for the EDS test, as shown in FIG. 6 , prevents damage to the I/O pad 26 . Although not illustrated in FIG. 6 , the test pad 26 a may be removed or covered before the electroless plating process.
[0046] As discussed above, in the interconnection structure according to exemplary embodiments, the I/O pad is expanded to the size required in the package level beyond the size limitations that exist at the chip level. Accordingly, the contact area between the I/O pad and the electroless plating layer is increased, and thereby metallic joints between both metal layers is strengthened. As a result, it is possible to prevent defects, such as cracks or delaminations of the metallic joints, and to improve the yield and reliability of the IC chip and the package.
[0047] The invention may be practiced in many ways. What follows are exemplary, non-limiting descriptions of exemplary embodiments of the invention.
[0048] According to some embodiments, the interconnection structure includes an IC chip with internal circuitry having terminals for electrical connections. The interconnection structure also includes a passivation layer disposed on a top surface of the IC chip that protects the internal circuitry and exposes the terminals. The structure further includes I/O pads having a first portion and a second portion, the first portion in contact with each terminal, and the second portion extended over the passivation layer. The structure further includes an electroless plating layer formed on the respective I/O pads.
[0049] According to some embodiments, the I/O pad may be formed of aluminum or copper.
[0050] According to other embodiments of the invention, the structure may further include a polymer layer that is disposed on the passivation layer. The polymer layer may be disposed under the second portions of the respective I/O pads, or on peripheral edges of the second portions of the respective I/O pads.
[0051] According to other embodiments of the invention, the structure may further include metal bumps that are disposed on the electroless plating layer. The metal bumps may be disposed at the same locations as the terminals, or at different locations.
[0052] According to other embodiments of the invention, the electroless plating layer may be formed of nickel. The electroless nickel plating layer may contain phosphorus or boron. In addition, the electroless nickel plating layer may be coated with a gold layer.
[0053] According to other embodiments of the invention, the electroless plating layer may contain zinc particles provided on the respective I/O pads. Additionally, the terminals may be formed of tungsten.
[0054] While the inventive aspects have been particularly shown and described with reference to several exemplary embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to these exemplary embodiments without departing from the spirit and scope of the invention as defined by the appended claims. | An interconnection structure includes an integrated circuit (IC) chip having internal circuitry and a terminal to electrically connect the internal circuitry to an external circuit, a passivation layer disposed on a top surface of the IC chip, the passivation layer configured to protect the internal circuitry and to expose the terminal, an input/output (I/O) pad, where the I/O pad includes a first portion in contact with the terminal and a second portion that extends over the passivation layer, and an electroless plating layer disposed on the I/O pad. | Briefly describe the main invention outlined in the provided context. | [
"CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a Continuation of U.S. patent application Ser.",
"No. 11/195,361, filed Aug. 1, 2005, now pending, which claims priority from Korean Patent Application No. 2004-60188, filed Jul. 30, 2004, the contents of which are hereby incorporated by reference in their entirety for all purposes.",
"BACKGROUND [0002] 1.",
"Technical Field [0003] This disclosure relates generally to an interconnection structure of an integrated circuit (IC) chip and, more particularly, to a structure associated with an input/output (I/O) pad having increased contact area with an electroless nickel plating layer.",
"[0004] 2.",
"Description of the Related Art [0005] Flip chip bonding technology and wafer level packaging technology may employ metal bumps which are distributed over a surface of the IC chip.",
"Such distribution of bump locations may provide several advantages of smaller package size, higher mounting density, improved electrical properties, etc.",
"in comparison with conventional interconnection and packaging technologies.",
"[0006] Typically, the metal bumps are formed on respective I/O pads exposed at the chip surface.",
"The I/O pads are chip terminals that allow signal/power access to and from chip internal circuitry.",
"While the metal bumps may be made of mainly solder, the I/O pads may be made of aluminum or copper.",
"Connections between the metal bump and the I/O pad may require under bump metal (UBM) layers.",
"The UBM layers may act as an adhesive layer, a diffusion barrier, a plating base, and a solder wetting layer.",
"[0007] As well known in the art, the UBM layers may be composed of one or more layers and are formed through a complicated process.",
"To form the UBM layers, several metals are deposited in sequence by sputtering, for example, which are then covered with photoresist material.",
"The photoresist material is selectively removed by exposure and development, thus producing a desired photoresist pattern.",
"Then bump metal is deposited using electroplating, for example, on the pre-deposited UBM metals through the photoresist pattern.",
"After the photoresist pattern is completely removed, the UBM metals are etched using the bump metal as an etch mask.",
"These complicated processes may incur increases in time and cost.",
"[0008] Electroless plating techniques, or electroplating, can uniformly and simply form a plating layer by dipping an object to be plated in a bath containing an appropriate chemical solution.",
"Through an electrolysis process, products from the chemical solution are selectively deposited on the UBM layers on the I/O pads, thus eliminating the need for photoresist material, related processes, and etching of the UBM layers.",
"[0009] FIG. 1 is a sectional diagram illustrating a conventional interconnection structure of an IC chip.",
"Referring to FIG. 1 , the IC chip 10 has a tungsten pad 11 disposed on an upper portion of the chip.",
"The tungsten pad 11 is a terminal for internal chip circuitry.",
"An I/O pad 12 is formed of aluminum or copper on the tungsten pad 11 .",
"A top surface of the IC chip 10 is covered with a passivation layer 13 and a polymer layer 14 for protecting the chip internal circuitry.",
"The I/O pad 12 is exposed through the passivation layer 13 and the polymer layer 14 .",
"[0010] Minute zinc particles 15 are formed on the I/O pad 12 using a zincating, or zinc immersion, technique.",
"The zinc particles 15 may act as a plating core during electroless plating.",
"A surface of the I/O pad 12 is coated with a nickel layer 16 through chemical reduction.",
"A ball-shaped solder bump 17 is formed on the nickel layer 16 acting as the UBM layer.",
"[0011] In this conventional interconnection structure, a contact area between the I/O pad 12 and the electroless nickel plating layer 16 is relatively small.",
"For example, the diameter of the circular-shaped nickel layer 16 is about 135 μm.",
"However, the diameter or width of the I/O pad 12 is about 70 μm, and further, an exposed part of the I/O pad 12 is only about 50 μm in diameter.",
"This may cause a difference between the size of the I/O pad 12 allowed at the chip level and the size of the plating layer 16 required at the package level.",
"[0012] Since the contact area between the I/O pad 12 and the plating layer 16 is limited to the exposed part of the I/O pad 12 , metallic joints between both metal layers 12 and 16 may often be unsatisfactory.",
"Therefore, when the metallic joints are subjected to thermally inducted stress, cracks or delaminations may occur in the metallic joints, which raises concerns regarding yield and reliability.",
"[0013] Embodiments of the invention address these and other disadvantages of the conventional art.",
"SUMMARY [0014] Embodiments of the invention provide an interconnection structure for an integrated circuit (IC) chip in which the connections between metallic input/output (I/O) pads and metallic plating layers are strengthened.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 is a sectional diagram illustrating a conventional interconnection structure of an IC chip.",
"[0016] FIG. 2 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with some embodiments of the invention.",
"[0017] FIGS. 3A to 3 E are sectional diagrams illustrating a sequence of exemplary processes for forming the interconnection structure of FIG. 2 .",
"[0018] FIG. 4 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with some other embodiments of the invention.",
"[0019] FIG. 5 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with more embodiments of the invention.",
"[0020] FIG. 6 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with different embodiments of the invention.",
"DETAILED DESCRIPTION [0021] Exemplary, non-limiting embodiments of the invention are described more fully below with reference to the accompanying drawings.",
"This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein.",
"Rather, the disclosed embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the teachings of the invention to those skilled in the art.",
"As will be recognized by those of skill in the art, the teachings of this invention may be employed in varied and numerous embodiments without departing from said teachings.",
"[0022] To avoid unnecessarily obscuring the inventive aspects of the exemplary embodiments, well-known structures and processes may not be described or illustrated in detail.",
"Furthermore, for simplicity and clarity of illustration, the figures are not drawn to scale.",
"Rather, the dimensions of some of the elements are exaggerated relative to other elements.",
"Throughout the drawings, like reference numerals are used to indicate similar parts.",
"Furthermore, it should be recognized that the structure illustrated in the following figures, which shows only one small part of an IC chip, my be repeated over the entire IC chip and similarly, over a whole wafer.",
"[0023] FIG. 2 is a sectional diagram illustrating an interconnection structure of an IC chip 20 in accordance with some embodiments of the invention.",
"A tungsten pad 21 is disposed on an upper portion of the IC chip 20 .",
"The IC chip 20 has internal circuitry (not shown), and the tungsten pad 21 is provided as a terminal for internal chip circuitry.",
"The tungsten pad 21 may be formed of some other suitable material besides tungsten.",
"The IC chip 20 may be a memory device such as DRAM, SRAM, or flash memory, or it may be a non-memory device such as a logic device.",
"[0024] A top surface of the IC chip 20 is covered with a passivation layer 22 .",
"The passivation layer 22 provides protection to the chip internal circuitry and may be formed of silicon nitride or silicon oxide.",
"A polymer layer 23 covers the passivation layer 22 .",
"The polymer layer 23 may be formed of polyimide, for example, and provides electrical isolation, protection, and stress dispersion.",
"The tungsten pad 21 is exposed through the passivation layer 22 and the polymer layer 23 .",
"[0025] An I/O pad 26 is disposed above the tungsten pad 21 and extends to a top surface of the polymer layer 23 .",
"That is, a central portion of the I/O pad 26 is in contact with the tungsten pad 21 , and a peripheral portion of the I/O pad 26 is in contact with the polymer layer 23 around the tungsten pad 21 .",
"The I/O pad 26 may be formed of aluminum or copper.",
"Minute zinc particles 27 are formed on the I/O pad 26 using a zinc immersion, or zincating, technique.",
"The zinc particles 27 may act as a plating core during a subsequent electroless plating process.",
"[0026] In the electroless plating process, a surface of the I/O pad 26 is coated with a suitable plating layer 28 through chemical reduction.",
"The electroless plating layer 28 may be formed of nickel and acts as the UBM layer.",
"Phosphorus or boron may be added to the nickel, and a gold layer may be deposited on the nickel layer.",
"A metal bump 29 , such as a ball-shaped solder bump, may be formed on the electroless plating layer 28 .",
"[0027] As discussed above, the I/O pad 26 that extends to the top surface of the polymer layer 23 may satisfy the size requirement of the package level.",
"In comparison with the aforementioned conventional structure, an exposed part of the tungsten pad 21 may remain about 50 μm in diameter.",
"However, the diameter of the I/O pad 26 may approximate 135 μm, which is substantially equal to that of the electroless plating layer 28 .",
"As a result, the contact area between the I/O pad 26 and the electroless plating layer 28 is increased about 7.3 times compared to the conventional structure.",
"[0028] FIGS. 3A to 3 E are sectional diagrams illustrating a sequence of exemplary processes for forming the interconnection structure of FIG. 2 .",
"[0029] Referring to FIG. 3A , the tungsten pad 21 is formed on the upper portion of the IC chip 20 during a wafer fabrication process.",
"The tungsten pad 21 is provided as a terminal of the chip internal circuitry.",
"The passivation layer 22 and the polymer layer 23 are deposited in sequence on the top surface of the IC chip 20 , providing protection, electrical isolation, and stress dispersion.",
"[0030] The passivation layer 22 may be formed of silicon nitride or silicon oxide, and the polymer layer 23 may be formed of polyimide, epoxy, benzo-cyclo-butene (BCB), or other suitable polymeric material.",
"Portions of the passivation layer 22 and the polymer layer 23 are removed to selectively expose the tungsten pad 21 to the outside.",
"Layer deposition and selective removal processes are well known in this art, and therefore a detailed description of the same is omitted.",
"Furthermore, it will be appreciated that such processes may be performed simultaneously on the whole wafer.",
"[0031] Referring to FIG. 3B , a pad metal layer 24 may be deposited over all exposed surfaces on the wafer.",
"The pad metal layer 24 may be formed of aluminum, copper, or another suitable conductive material.",
"The pad metal layer 24 may be deposited using a physical vapor deposition (PVD) process, such as sputtering.",
"The thickness of the pad metal layer 24 may be about 8000 Å.",
"[0032] Referring to FIG. 3C , a photoresist pattern 25 is provided on the pad metal layer 24 around the tungsten pad 21 .",
"As is well known, a photoresist material that is coated, selectively exposed, and developed may be used to form the photoresist pattern 25 .",
"The pad metal layer 24 is selectively etched using the photoresist pattern 25 as an etch mask.",
"The pad metal layer remains only under the photoresist pattern 25 , thus forming the I/O pad 26 .",
"[0033] Referring to FIG. 3D , the photoresist pattern 25 is completely removed, and thereby the I/O pad 26 is exposed to the outside.",
"Next, zinc particles 27 are formed on the I/O pad 26 using a zincating technique that employs a zincate solution.",
"Since zincating techniques are well known in the art, a detailed description of the same is omitted.",
"Although the size of the zinc particles 27 are exaggerated for clarity, in reality the size of the zinc particles 27 may be negligible.",
"The zinc particles 27 may act as a plating core that may promote combination of the I/O pad 26 and plating material during a subsequent electroless plating process.",
"[0034] Referring to FIG. 3E , after the zinc particles 27 are formed, the electroless plating layer 28 is deposited on the I/O pad 26 through chemical reduction by an electroless plating process.",
"The electroless plating layer 28 may be formed of nickel, phosphorus-added nickel, or boron-added nickel.",
"After deposition of the nickel layer 28 , a gold layer may be deposited thereon to prevent oxidation.",
"The electroless nickel layer 28 may have a thickness of several microns (μm), and the gold layer may have a thickness of about 0.1 μm.",
"[0035] In alternative embodiments, the I/O pad 26 may be formed between the passivation layer 22 and the polymer layer 23 .",
"[0036] FIG. 4 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with some other embodiments of the invention.",
"[0037] Referring to FIG. 4 , the I/O pad 26 is formed just after the passivation layer 22 is formed on the top surface of the IC chip 20 .",
"The I/O pad 26 has a central portion in contact with the tungsten pad 21 , and a peripheral portion in contact with the passivation layer 22 around the tungsten pad 21 .",
"The I/O pad 26 may be formed through the same processes as those described above for FIGS. 3A-3E .",
"[0038] The polymer layer 23 is coated on the whole wafer including the I/O pad 26 , and then a portion of the polymer layer 23 is removed to expose the I/O pad 26 .",
"An exposed area of the I/O pad 26 is greater than the area of the I/O pad that is contact with the tungsten pad 21 .",
"The zinc particles 27 are formed on the I/O pad 26 , and then the electroless plating layer 28 is deposited thereon.",
"[0039] In the embodiments described above, the solder bump 29 is disposed at approximately the same location, that is, above the tungsten pad 21 .",
"In alternative embodiments, the solder bump 29 may be disposed at other locations that are separated from the tungsten pad 21 .",
"[0040] FIG. 5 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with more embodiments of the invention.",
"[0041] Referring to FIG. 5 , the I/O pad 26 not only acts as a normal pad on which the solder bump 29 is mounted, but also functions as a typical redistribution or rerouting line.",
"A first portion of the I/O pad 26 is placed on the tungsten pad 21 , and a second portion of the I/O pad 26 is extended along the top surface of the polymer layer 23 to the solder bump 29 .",
"Altering the photoresist pattern 25 shown in FIG. 3C may form this structure of the I/O pad 26 used as a redistribution line.",
"[0042] Such a structure may further include an upper additional polymer layer 30 .",
"Alternatively, the I/O pad 26 used as a redistribution line may be disposed between the passivation layer 22 and the polymer layer 23 .",
"[0043] According to embodiments of the invention, the I/O pad 26 may also act as a test pad.",
"[0044] FIG. 6 is a sectional diagram illustrating an interconnection structure of an IC chip in accordance with different embodiments of the invention.",
"[0045] Referring to FIG. 6 , one portion of the I/O pad 26 is extended along the top surface of the passivation layer 22 .",
"After the wafer fabrication process, the IC chip 20 may undergo an electrical die sorting (EDS) test.",
"In the EDS test, a test probe 31 is typically contacted with the I/O pad 26 so as to implement electrical tests.",
"However, this may cause damage to the I/O pad 26 .",
"A separate pad 26 a for the EDS test, as shown in FIG. 6 , prevents damage to the I/O pad 26 .",
"Although not illustrated in FIG. 6 , the test pad 26 a may be removed or covered before the electroless plating process.",
"[0046] As discussed above, in the interconnection structure according to exemplary embodiments, the I/O pad is expanded to the size required in the package level beyond the size limitations that exist at the chip level.",
"Accordingly, the contact area between the I/O pad and the electroless plating layer is increased, and thereby metallic joints between both metal layers is strengthened.",
"As a result, it is possible to prevent defects, such as cracks or delaminations of the metallic joints, and to improve the yield and reliability of the IC chip and the package.",
"[0047] The invention may be practiced in many ways.",
"What follows are exemplary, non-limiting descriptions of exemplary embodiments of the invention.",
"[0048] According to some embodiments, the interconnection structure includes an IC chip with internal circuitry having terminals for electrical connections.",
"The interconnection structure also includes a passivation layer disposed on a top surface of the IC chip that protects the internal circuitry and exposes the terminals.",
"The structure further includes I/O pads having a first portion and a second portion, the first portion in contact with each terminal, and the second portion extended over the passivation layer.",
"The structure further includes an electroless plating layer formed on the respective I/O pads.",
"[0049] According to some embodiments, the I/O pad may be formed of aluminum or copper.",
"[0050] According to other embodiments of the invention, the structure may further include a polymer layer that is disposed on the passivation layer.",
"The polymer layer may be disposed under the second portions of the respective I/O pads, or on peripheral edges of the second portions of the respective I/O pads.",
"[0051] According to other embodiments of the invention, the structure may further include metal bumps that are disposed on the electroless plating layer.",
"The metal bumps may be disposed at the same locations as the terminals, or at different locations.",
"[0052] According to other embodiments of the invention, the electroless plating layer may be formed of nickel.",
"The electroless nickel plating layer may contain phosphorus or boron.",
"In addition, the electroless nickel plating layer may be coated with a gold layer.",
"[0053] According to other embodiments of the invention, the electroless plating layer may contain zinc particles provided on the respective I/O pads.",
"Additionally, the terminals may be formed of tungsten.",
"[0054] While the inventive aspects have been particularly shown and described with reference to several exemplary embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to these exemplary embodiments without departing from the spirit and scope of the invention as defined by the appended claims."
] |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to litter removal systems adapted for use in present day vehicles.
2. Description of the Prior Art
In U.S. Pat. No. 3,648,837, the inventor in that patent being the same as the applicant herein, there is shown an automobile litter removal system where litter is drawn through removal tubes into litter receptacles in the engine compartment of the automobile. Suction to operate these systems is provided by a blower that is powered from the crank shaft of the engine through the automobile pulley arrangement and a magnetic clutch.
Also it has been proposed in the prior art to operate an automobile litter removal system by means of the suction created by the intake manifold of the automobile. Such devices are shown in Leland, U.S. Pat. No. 2,656,039; Frost, U.S. Pat. No. 3,011,627, and Elswood, U.S. Pat. No. 3,062,363.
Further, there is shown in the prior art, litter removal systems which are powered by electric motors specifically provided for that purpose. Typical of these are: Nicholas, U.S. Pat. No. 2,680,569; Thompson, U.S. Pat. No. 2,851,156; Nickless, U.S. Pat. No. 3,230,567; and Coleman, U.S. Pat. No. 3,500,492.
It is an object of the present invention to provide an improved litter removal system for a vehicle such as an automobile, which system operates in conjunction with conventional vehicle components in a manner to provide effective removal of the litter.
SUMMARY OF THE INVENTION
The present invention is adapted for installation in a vehicle such as a conventional present day automobile, truck, pleasure water craft, etc., and is arranged to operate in combination with the existing air ventilating blower system of the vehicle, which conventionally provides a flow of air either through a heater or a bypass passage or through both the heater and the bypass passage. There is a litter receptacle means mounted to the vehicle for collection of litter from the passenger compartment, a removal tube means leading from the passenger compartment to said receptacle, and suction means leading from the receptacle means to an existing intake housing of the vehicle blower system. In the preferred embodiment, when the litter removal system is activated, the air intake opening of the inlet housing is closed and the blower is operated to create a suction in the intake housing sufficient to cause an air flow through the removal tube of a velocity sufficient to move litter placed in the removal tube.
In the particular configuration shown herein, there is a main litter removal system having its own removal tube and suction tube, to remove litter such as cans, napkins, etc. There is a closure cap at the inlet of the removal tube, and the opening of this closure cap activates a switch which causes closure of the inlet of the blower intake housing and also causes operation of the blower. There is an ash tray removal system, also having its own receptacle, inlet tube and suction tube. Closure of the ash tray operates a time delay switch to also close the intake housing valve and operate the blower. After a short interval of time, the switch automatically shuts off to permit the intake valve to open and de-energize the blower. In another embodiment, the collector tube itself serves the additional function of the receptacle.
According to another facet of the present invention, it has been found that by sizing the removal tube of the main litter removal system properly, conventional present day beverage containers can be carried in the tube very effectively. Other features of the present invention will become apparent from the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view illustrating the apparatus of the present invention in a conventional automobile;
FIG. 2 is a top plan view of the apparatus shown in FIG. 1;
FIG. 3 is a sectional view of a portion of the main litter removal system of the present invention;
FIG. 4 is an exploded view illustrating the litter receptacle of the system shown in FIG. 3;
FIG. 5 is a view similar to FIG. 4, but showing a second form of a litter receptacle;
FIG. 6 is a sectional view of the receptacle of FIG. 5 shown assembled;
FIG. 7 is a sectional view of the ash tray removal system of the present invention;
FIG. 8 is a sectional view of a second ash tray suitable for use in the present invention;
FIG. 9 is a side elevational view of a modified main litter removal system;
FIG. 10 is a sectional view taken along line 10--10 of FIG. 9, and
FIG. 11 is a longitudinal sectional view of the removal tube of the main litter removal system, with a conventional beverage container shown being moved therein.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will be described below with reference to present day automobiles, it being understood that it could also be applied to other vehicles, such as trucks, pleasure water craft, etc. The first embodiment of the present invention is illustrated in FIGS. 1 through 8. In FIGS. 1 and 2 there is shown portions of a conventional automobile 10, comprising a passenger compartment 12 with a dash board 14, and an engine compartment 16 having a conventional automobile engine 18 and a fire wall 19. In the over all litter removal or evacuation apparatus of the present invention, there are two interrelated systems. First, there is a main litter removal system 20 for evacuating miscellaneous litter such as bottles, cans, garbage, paper and this type of litter generated by the occupants of a vehicle, this litter hereinafter being referred to as "major litter." Secondly, there is an ash tay removal or evacuation system 22, adapted to remove cigar butts, cigarette butts, ashes and the like from the automobile ash tray. As will be described more particularly hereinafter, these 2 litter removal systems 20 and 22 are arranged to work in combination with the conventional heating and ventilating system of the automobile 10, such a system being shown in FIG. 2, and designated generally 26.
The main litter removal system 20 comprises a litter receptacle 28, a removal conduit 30 and a suction conduit 32. One form of the receptacle 28 is shown in FIGS. 3 and 4, and comprises a semi-flexible containing member 34, a closure lid 36 and a spring retainer 38. The upper edge of the containing member 34 fits over a peripheral groove 40 in the lid 36, and the wire clamp 38 presses the upper portion of the containing member 34 into the groove 40 to make a substantially airtight connection between the lid 36 and the containing member 34. By squeezing a crossed handle member 42 of the retaining clamp 38, the clamp 38 can be expanded to release the containing member 34 from the lid 36 so that the containing member 34 can be emptied of its accumulated litter.
The litter removal conduit 30 has its inlet end 44 located at a convenient location at the automobile dash board 14 at a level moderately above that of the lid 36 of the receptacle 28. The inlet 44 has a hinge mounted closure cap 46 which is spring loaded toward its closed position, shown in full lines in FIGS. 1 and 2. The outlet end 48 of the conduit 30 opens into the receptacle 30 through the lid 36 to which the conduit 30 is firmly attached in a substantially airtight connection. The conduit 30 is made of moderately flexible material and has a hinged connection 50 at the fire wall 19 of the automobile 10 so that the entire receptacle 20 can be move upwardly for easy removal and replacing the containing member 28.
The suction conduit 32 has its inlet end 52 connected to the receptacle 28 through the lid 26. The outlet end 54 of the suction tube 32 opens into an air intake housing 56 of the automobile heating and air ventilation system 26. As will be described more particularly hereinafter, a negative pressure is applied to the suction tube 32 which causes air flow through the inlet of the removal conduit 30 and into the receptacle 28, this inflow of air pushing litter through the conduit 30 into the receptacle 28. At the outlet of the suction tube 32, there is provided a flap type check valve which opens under moderate pressure to permit flow through the tube 32 into the intake chamber 56 when the system is energized, and prevents any backflow entering the tube 32 from the chamber 56.
A second form of the receptacle for the main litter removal system is shown in FIGS. 5 and 6. There is a containing member 34a made of a flexible yet airtight material, and it is connected to a top plate 34b, having openings 34c and 34d for the conduits 30 and 32. There is a lid 36a having depending U-shaped wire members 36b, which extend through end slots 34e in the container plate 34b to prevent the containing member 34a from collapsing when a negative pressure is applied. A protective plate 36c of a suitable heat resistant material depends from one side of the lid 36a to protect the containing member 34a from the heat of the engine.
The ash tray removal system 22 is functionally similar to the main litter removal system 20, and comprises a receptacle 58, a removal conduit 60 and a suction conduit 62. The receptacle 58 comprises an annular containing member 64 comprising outer and inner concentric cylindrical walls 66 and 68 defining therein an annular retaining chamber 70. The lower portion of the chamber 70 is filled with a scented water. The top of the inner wall 68 is closed, except that a plurality of relatively small holes 72 are formed in the upper portion of the wall 68. The suction tube 62 communicates with the lower open end of the inner wall 68 so that air in the receptacle chamber 70 is drawn through the openings 72 and through the suction tube 62.
There is a closure lid 74 which fits over the receptacle 64 to form a substantially airtight seal, and the outlet portion 76 of the conduit 60 is connected to the lid 74. The tube 60 has a hinged connection 78 at the automobile fire wall 19 in a manner generally similar to the conduit 30 of the main litter removal system 20. This permits the lid 74 to be lifted and the container 64 to be removed for dumping the ash tray refuse.
An ash tray configuration particularly adapted for use in the present invention is shown in FIG. 7. This ash tray 80 comprises a cylindrical container 82 slide mounted in the inlet 84 of the removal conduit 60. The upper top of the container 82 is opened at 86 to permit the insertion of cigarettes, cigars, etc., and the outer end of the container 82 is closed by a cap 88 providing a peripheral lip by which the ash tray can be pulled out to its open position, as shown in dotted lines of FIG. 7, or pushed into its closed position, as shown in full lines of FIG. 7. The cylindrical configuration of the ash tray housing 82 tends to align the cigarette butts and cigar butts longitudinally with respect to the conduit 60, so that such ash tray refuse passes more easily through the conduit 60 into the receptacle 58.
A second form of an ash tray suitable for use in the present invention is shown at 90 in FIG. 8. There is a container 92 formed as an arcuate section of a cylinder and hinge mounted at 94 for swing movement relative to a stationary curved housing plate 96. When the container 92 is swung to its closed position, shown in full lines of FIG. 8, the lower part of the container 92 communicates openly with the removal conduit 60.
As previously mentioned herein, the two litter removal systems 20 and 22 operate in conbination with the automobile heating and ventilating system 26. This system 26 is, except for the modifications to be described hereinafter, a conventional heating and ventilating system, and accordingly it will be described only briefly herein. The aforementioned housing 56 communicates with the automobile air intake vent or opening 106 positioned just forward of the automobile windshield. There is a blower 108 powered by an electrical motor 110 which draws outside air through the intake vent 106 into the intake housing 56, and blows this air under moderate pressure into a distribution housing 112 located beneath the dash board 14. This housing 112 contains a heater 114 and also a heater bypass ventilating passage 116, and there is a plate-like valve 118 which selectively directs the air from the blower 108 through either the heater 114 or passage 116, or through both heater 114 and passage 116.
The components of the heating and ventilating system 20 that have been disclosed thus far in this description of the preferred embodiment are common to many present day automobiles. In the preferred form of the present invention, this conventional heating and ventilating system is modified by providing a closure valve, generally designated 120 by which the intake vent 106 is selectively closed. As shown herein, this valve 120 comprises a valve plate 122 pivotally mounted to a shaft 124 positioned along the rear edge of the vent opening 106. Depending from the shaft 124 and fixedly attached thereto is a lever arm 126 which in turn is attached to an actuating rod 128 of a solenoid 130. Energizing the solenoid 130 retracts the rod 128 to swing the plate 128 upwardly to close the intake vent 106, while de-energizing the solenoid 130 permits this plate 128 to drop to its open position and permit inflow of outside air through the intake 106 and into the intake housing 26.
There are three separate switches by which the apparatus of the present invention can be activated. One switch 132 is mounted proximate the closure cap 46 of the main litter removal system 30 and is activated by opening the closure cap 46 to the dotted line position shown in FIG. 2. A second switch 134 is mounted proximate the ash tray 80 or 90 and is activated by closing the ash tray to the position shown in full lines in FIG. 7 or FIG. 8. A third switch 136 is mounted on the dash board 14 and is manually operated by a person in the passenger compartment 12.
Each of these switches 132, 134 and 136 functions to activate the solenoid 130 to raise the valve plate 122 to close the vent opening 106. There is another switch which is mounted in the solenoid 130 and closes upon activation of solenoid 130 to energize the blower motor 110 and cause the blower 108 to operate. With the intake opening 106 closed by the valve plate 122, the blower 108 reduces the pressure in the intake chamber 56 to create a suction in the two suction tubes 32 and 62.
In operation, let it be assumed first that major litter, such as cans, napkins, etc., is to be removed from the passenger compartment. The closure cap 46 is swung out to its open position, and the litter is placed in the inlet 44 of the litter removal tube 30. Opening of the cap 46 closes the switch 132 to energize the solenoid 130 to close the intake vent 106 by means of the plate 122 and start the blower 108 functioning. This sucks air from the passenger compartment 12 through the tube 30 and into the receptacle 28, with this flow of air through the tube 30 moving the litter placed in the tube 44 into the receptacle 28. A screen in the intake end of the tube 32 prevents litter from being drawn into the tube 32. The litter falls to the bottom of the receptacle 28 to be removed therefrom at a later time when container 34 is emptied, as described previously herein. When the closure cap 46 is released, it is spring loaded to return to its loaded position, thus opening the switch 132, to permit the plate 122 to drop to its open position and to de-energize the motor 110 to stop operation of the blower 108. It has been found that while the suction force created by the blower 108 in the tube 30 is sufficient to move litter through the tube 30, this suction normally does not draw any litter from the receptacle 28 to the inlet of the suction tube 32.
When it is desired to empty the ash tray 80 or 90, the ash tray 80 or 90 is moved to its closed position to activate the switch 134. In the same manner as described above this causes the valve plate 122 to close and activate the blower 108, thus creating a suction in the ash tray removal tube 60. There is sufficient leakage around the ash tray housing to permit sufficient velocity of air flow from the passenger compartment 12 through the relatively small ash tray removal tube 60 to blow the cigar butts, cigarette butts, ashes, etc., into the container 58. The ash tray switch 134 is a time delay switch which remains closed for a short period of time (e.g. five to ten seconds) and then automatically opens, such as an Amperite 12 Glo Time Delay Relay. Reactivation of the switch 134 is accomplished simply by opening the ash tray 80 or 90 and moving it back again to its closed position.
Removal of ash tray litter from the container 58 is accomplished by raising the lid 74, removing the container 58, dumping the litter and replacing the container 58 with additional scented water. At the outlet of the suction tube 62, there is provided a check valve in the form of a flap 138 which opens under moderate pressure to permit flow through the tube 62 into the intake chamber 56, but which prevents any backflow, for example by some wind blowing into intake housing 56, so that ashes are not blown back through the ash tray 80 or 90 into the passenger compartment 12. The ash tray litter receptacle 58 is so arranged that the litter falls to the bottom of the receptacle 58 and cannot be drawn through the top openings 72 that lead into the suction tube 62. While the suction from the blower 108 is sufficient to draw the ash tray litter into the receptacle 58, this suction is not so great as to draw ash tray litter from the receptacle 58 into the intake housing 56.
In FIGS. 9 and 10, there is shown a modified form of the main litter disposal system of the present invention. In this modified version, there is a disposal tube 150 which serves the dual function of a removal tube and a litter receptacle. This tube has an inlet end 152 located adjacent the dash board 14 of the automobile 10. From its inlet 152, the tube 150 has a first portion 150a which extends forwardly and generally horizontally, and a second forward section 150b which extends forwardly and downwardly in a moderate curve to a location forward of the front left wheel 154 of the automobile 10 within the body structure of the automobile.
The forward portion 150b of the tube 150 is curved downwardly with a moderate degree of curvature to terminate in a downwardly directed outlet opening 158. The outlet 158 is closed by a cap 160 pivotally mounted at 162 to the outlet end 158 of the tube 150. An operating lever 164 is rigidly connected to the cap 160 and is connected to an upstanding operating rod 166 which is urged downwardly by a compression spring assembly 168 to hold the cap 160 in its closed position. The cap 160 is swung downwardly to its open position, as shown in dotted lines of FIG. 9, by lifting the rod 166 by means of a knob 170 at the top end of the rod 166. When the knob 170 is released, the compression spring 168 acting on the rod 166 forces the cap 160 back to its closed position covering the forward outlet opening 158 of the tube 150.
There is a suction tube 172 positioned above the forward tube section 150a. As in the first embodiment of the invention, the outlet end 174 of the suction tube 172 connects to the air intake housing 56 of the heating and ventilating system 26 of the automobile 10. The intake end 176 of the suction tube 172 connects to tube 150 at approximately the transition area of the tube sections 150a and 150b, and communicates with the interior of the tube 150 through a plurality of holes 178 in the tube 150. The manner in which the heating and ventilating system 26 functions to provide a suction in the tube 172 is the same as that described in the first embodiment of the present invention. That is to say, when the inlet cap 180 for the tube 150 is opened, this closes a switch which activates the blower and closes the vent opening to create a suction which draws air into the suction tube 172.
In operation, when it is desired to dispose of litter, the closure cap 180 is opened to energize the system. Air is drawn from the interior of the tube 150 through the holes 176 into the suction tube 172 and into the intake housing 56 of the heating and ventilating system of the automobile. Since the forward outlet end 158 of the tube 150 is closed by the cap 160, there is a suction which draws air into the inlet 152 of the tube 150 to the location of the suction tube inlet 176. When a bottle, napkin, or other litter is deposited into the inlet 152, it is drawn downwardly and forwardly in the tube 150. As the litter reaches the forward downwardly curved portion 150b of the tube 150, normal gravity forces cause the litter to continue to the forward bottom outlet portion 158. At a later time, when it is desired to remove the litter from the system, the knob 170 is operated to open the cap 160, with the accumulated litter falling from the outlet 158 of the tube 172. In the event litter becomes stuck in the tube 150, high pressure air can be discharged into the tube 150 to blow the litter to the outlet end 158. For this purpose, an access opening is provided in the tube 150 adjacent the automobile firewall, this opening being normally closed by a removable cap 182.
Another facet of the present invention is the results achieved by the proper dimensioning of the main litter removal tube, which is designated 30 in the first embodiment and 150 in the second embodiment. For convenience, in describing this particular facet of the present invention, reference will be made only to the tube 30, it being understood that it is not limited to the particular configuration of that first embodiment. With reference to FIG. 11, there is shown a conventional beverage container 190 in the tube 30.
It has been found that if the inside diameter (indicated at A in FIG. 11) of the tube 30 is made three inches, within reasonably close tolerances, the removal of common present day beverage containers, such as soft drink cans or bottles, beer bottles, etc., is greatly facilitated. The outside diameter (indicated at B in FIG. 11) of the common present day beverage container is between a lower value of 2 and 5/8 inches and a higher value of two and thirteen-sixteenths inches. With the inside diameter of the tube 30 being just slightly larger (i.e. three-eighths of an inch to three-sixteenths of an inch) than the diameter of the beverage containers, there is sufficient clearance so that the beverage container 190 does not become caught in the tube 30, and yet the beverage container provides a sufficient obstacle to the flow of air so that it is moved along by the air stream.
In addition to the above, it is believed that another physical phenomenon takes place. As air is sucked from the area of the tube 30 downstream of the beverage container 190, air flows forwardly around the small passageway 192 formed between the tube 30 and the container 190. Since the container 190 tends to rest on the bottom of the tube 30, this passageway 192 is larger above the container 190, which results in an increased velocity of air flow above the container 190. Since an increase in air velocity, according to Bernouli's law, causes a corresponding decrease in static pressure, it can reasonably be assumed that there is a pressure decrease above the container 190 which tends to lift the container 190 off the bottom of the tube 30. This in turn decreases the frictional forces between the container 190 and the tube 30 which facilitates travel of the container through the tube 30.
Regardless of the correctness of the above theory, it has been found that proper dimensioning of the tube 30 is quite critical to the operation of the present invention. For example, if the inside diameter of the tube 30 is made as great as 31/4 inches, the system is much less effective in carrying common beverage containers; and if it is as small as 2 3/4 inches, there is a tendency to impede travel of the container through the tube 30. | A litter removal or evacuation apparatus for installation in a vehicle such as an automobile, truck, pleasure water craft, etc. There is a main litter removal system for larger articles such as bottles, napkins, etc; and an ash tray removal system to evacuate cigarette butts, cigar butts, etc., from the vehicle ash tray. In each of these two systems, there is a litter receptacle to receive the litter, a removal tube leading from the vehicle passenger compartment to the receptacle, and a suction tube leading from its related receptacle to the intake housing of the conventional heating and ventilating system of the vehicle. A suction adequate to draw litter through the removal tubes into the litter receptacles is created through the blower system of the vehicle heating and ventilating system, by simultaneously closing off the intake vent through which ambient air is normally drawn into the heating and ventilating system, and also operating the blower. In a second embodiment an elongate removal tube also acts as a receptacle for the litter. | Summarize the key points of the given patent document. | [
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present invention relates generally to litter removal systems adapted for use in present day vehicles.",
"Description of the Prior Art In U.S. Pat. No. 3,648,837, the inventor in that patent being the same as the applicant herein, there is shown an automobile litter removal system where litter is drawn through removal tubes into litter receptacles in the engine compartment of the automobile.",
"Suction to operate these systems is provided by a blower that is powered from the crank shaft of the engine through the automobile pulley arrangement and a magnetic clutch.",
"Also it has been proposed in the prior art to operate an automobile litter removal system by means of the suction created by the intake manifold of the automobile.",
"Such devices are shown in Leland, U.S. Pat. No. 2,656,039;",
"Frost, U.S. Pat. No. 3,011,627, and Elswood, U.S. Pat. No. 3,062,363.",
"Further, there is shown in the prior art, litter removal systems which are powered by electric motors specifically provided for that purpose.",
"Typical of these are: Nicholas, U.S. Pat. No. 2,680,569;",
"Thompson, U.S. Pat. No. 2,851,156;",
"Nickless, U.S. Pat. No. 3,230,567;",
"and Coleman, U.S. Pat. No. 3,500,492.",
"It is an object of the present invention to provide an improved litter removal system for a vehicle such as an automobile, which system operates in conjunction with conventional vehicle components in a manner to provide effective removal of the litter.",
"SUMMARY OF THE INVENTION The present invention is adapted for installation in a vehicle such as a conventional present day automobile, truck, pleasure water craft, etc.",
", and is arranged to operate in combination with the existing air ventilating blower system of the vehicle, which conventionally provides a flow of air either through a heater or a bypass passage or through both the heater and the bypass passage.",
"There is a litter receptacle means mounted to the vehicle for collection of litter from the passenger compartment, a removal tube means leading from the passenger compartment to said receptacle, and suction means leading from the receptacle means to an existing intake housing of the vehicle blower system.",
"In the preferred embodiment, when the litter removal system is activated, the air intake opening of the inlet housing is closed and the blower is operated to create a suction in the intake housing sufficient to cause an air flow through the removal tube of a velocity sufficient to move litter placed in the removal tube.",
"In the particular configuration shown herein, there is a main litter removal system having its own removal tube and suction tube, to remove litter such as cans, napkins, etc.",
"There is a closure cap at the inlet of the removal tube, and the opening of this closure cap activates a switch which causes closure of the inlet of the blower intake housing and also causes operation of the blower.",
"There is an ash tray removal system, also having its own receptacle, inlet tube and suction tube.",
"Closure of the ash tray operates a time delay switch to also close the intake housing valve and operate the blower.",
"After a short interval of time, the switch automatically shuts off to permit the intake valve to open and de-energize the blower.",
"In another embodiment, the collector tube itself serves the additional function of the receptacle.",
"According to another facet of the present invention, it has been found that by sizing the removal tube of the main litter removal system properly, conventional present day beverage containers can be carried in the tube very effectively.",
"Other features of the present invention will become apparent from the following detailed description.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view illustrating the apparatus of the present invention in a conventional automobile;",
"FIG. 2 is a top plan view of the apparatus shown in FIG. 1;",
"FIG. 3 is a sectional view of a portion of the main litter removal system of the present invention;",
"FIG. 4 is an exploded view illustrating the litter receptacle of the system shown in FIG. 3;",
"FIG. 5 is a view similar to FIG. 4, but showing a second form of a litter receptacle;",
"FIG. 6 is a sectional view of the receptacle of FIG. 5 shown assembled;",
"FIG. 7 is a sectional view of the ash tray removal system of the present invention;",
"FIG. 8 is a sectional view of a second ash tray suitable for use in the present invention;",
"FIG. 9 is a side elevational view of a modified main litter removal system;",
"FIG. 10 is a sectional view taken along line 10--10 of FIG. 9, and FIG. 11 is a longitudinal sectional view of the removal tube of the main litter removal system, with a conventional beverage container shown being moved therein.",
"DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will be described below with reference to present day automobiles, it being understood that it could also be applied to other vehicles, such as trucks, pleasure water craft, etc.",
"The first embodiment of the present invention is illustrated in FIGS. 1 through 8.",
"In FIGS. 1 and 2 there is shown portions of a conventional automobile 10, comprising a passenger compartment 12 with a dash board 14, and an engine compartment 16 having a conventional automobile engine 18 and a fire wall 19.",
"In the over all litter removal or evacuation apparatus of the present invention, there are two interrelated systems.",
"First, there is a main litter removal system 20 for evacuating miscellaneous litter such as bottles, cans, garbage, paper and this type of litter generated by the occupants of a vehicle, this litter hereinafter being referred to as "major litter.",
""",
"Secondly, there is an ash tay removal or evacuation system 22, adapted to remove cigar butts, cigarette butts, ashes and the like from the automobile ash tray.",
"As will be described more particularly hereinafter, these 2 litter removal systems 20 and 22 are arranged to work in combination with the conventional heating and ventilating system of the automobile 10, such a system being shown in FIG. 2, and designated generally 26.",
"The main litter removal system 20 comprises a litter receptacle 28, a removal conduit 30 and a suction conduit 32.",
"One form of the receptacle 28 is shown in FIGS. 3 and 4, and comprises a semi-flexible containing member 34, a closure lid 36 and a spring retainer 38.",
"The upper edge of the containing member 34 fits over a peripheral groove 40 in the lid 36, and the wire clamp 38 presses the upper portion of the containing member 34 into the groove 40 to make a substantially airtight connection between the lid 36 and the containing member 34.",
"By squeezing a crossed handle member 42 of the retaining clamp 38, the clamp 38 can be expanded to release the containing member 34 from the lid 36 so that the containing member 34 can be emptied of its accumulated litter.",
"The litter removal conduit 30 has its inlet end 44 located at a convenient location at the automobile dash board 14 at a level moderately above that of the lid 36 of the receptacle 28.",
"The inlet 44 has a hinge mounted closure cap 46 which is spring loaded toward its closed position, shown in full lines in FIGS. 1 and 2.",
"The outlet end 48 of the conduit 30 opens into the receptacle 30 through the lid 36 to which the conduit 30 is firmly attached in a substantially airtight connection.",
"The conduit 30 is made of moderately flexible material and has a hinged connection 50 at the fire wall 19 of the automobile 10 so that the entire receptacle 20 can be move upwardly for easy removal and replacing the containing member 28.",
"The suction conduit 32 has its inlet end 52 connected to the receptacle 28 through the lid 26.",
"The outlet end 54 of the suction tube 32 opens into an air intake housing 56 of the automobile heating and air ventilation system 26.",
"As will be described more particularly hereinafter, a negative pressure is applied to the suction tube 32 which causes air flow through the inlet of the removal conduit 30 and into the receptacle 28, this inflow of air pushing litter through the conduit 30 into the receptacle 28.",
"At the outlet of the suction tube 32, there is provided a flap type check valve which opens under moderate pressure to permit flow through the tube 32 into the intake chamber 56 when the system is energized, and prevents any backflow entering the tube 32 from the chamber 56.",
"A second form of the receptacle for the main litter removal system is shown in FIGS. 5 and 6.",
"There is a containing member 34a made of a flexible yet airtight material, and it is connected to a top plate 34b, having openings 34c and 34d for the conduits 30 and 32.",
"There is a lid 36a having depending U-shaped wire members 36b, which extend through end slots 34e in the container plate 34b to prevent the containing member 34a from collapsing when a negative pressure is applied.",
"A protective plate 36c of a suitable heat resistant material depends from one side of the lid 36a to protect the containing member 34a from the heat of the engine.",
"The ash tray removal system 22 is functionally similar to the main litter removal system 20, and comprises a receptacle 58, a removal conduit 60 and a suction conduit 62.",
"The receptacle 58 comprises an annular containing member 64 comprising outer and inner concentric cylindrical walls 66 and 68 defining therein an annular retaining chamber 70.",
"The lower portion of the chamber 70 is filled with a scented water.",
"The top of the inner wall 68 is closed, except that a plurality of relatively small holes 72 are formed in the upper portion of the wall 68.",
"The suction tube 62 communicates with the lower open end of the inner wall 68 so that air in the receptacle chamber 70 is drawn through the openings 72 and through the suction tube 62.",
"There is a closure lid 74 which fits over the receptacle 64 to form a substantially airtight seal, and the outlet portion 76 of the conduit 60 is connected to the lid 74.",
"The tube 60 has a hinged connection 78 at the automobile fire wall 19 in a manner generally similar to the conduit 30 of the main litter removal system 20.",
"This permits the lid 74 to be lifted and the container 64 to be removed for dumping the ash tray refuse.",
"An ash tray configuration particularly adapted for use in the present invention is shown in FIG. 7. This ash tray 80 comprises a cylindrical container 82 slide mounted in the inlet 84 of the removal conduit 60.",
"The upper top of the container 82 is opened at 86 to permit the insertion of cigarettes, cigars, etc.",
", and the outer end of the container 82 is closed by a cap 88 providing a peripheral lip by which the ash tray can be pulled out to its open position, as shown in dotted lines of FIG. 7, or pushed into its closed position, as shown in full lines of FIG. 7. The cylindrical configuration of the ash tray housing 82 tends to align the cigarette butts and cigar butts longitudinally with respect to the conduit 60, so that such ash tray refuse passes more easily through the conduit 60 into the receptacle 58.",
"A second form of an ash tray suitable for use in the present invention is shown at 90 in FIG. 8. There is a container 92 formed as an arcuate section of a cylinder and hinge mounted at 94 for swing movement relative to a stationary curved housing plate 96.",
"When the container 92 is swung to its closed position, shown in full lines of FIG. 8, the lower part of the container 92 communicates openly with the removal conduit 60.",
"As previously mentioned herein, the two litter removal systems 20 and 22 operate in conbination with the automobile heating and ventilating system 26.",
"This system 26 is, except for the modifications to be described hereinafter, a conventional heating and ventilating system, and accordingly it will be described only briefly herein.",
"The aforementioned housing 56 communicates with the automobile air intake vent or opening 106 positioned just forward of the automobile windshield.",
"There is a blower 108 powered by an electrical motor 110 which draws outside air through the intake vent 106 into the intake housing 56, and blows this air under moderate pressure into a distribution housing 112 located beneath the dash board 14.",
"This housing 112 contains a heater 114 and also a heater bypass ventilating passage 116, and there is a plate-like valve 118 which selectively directs the air from the blower 108 through either the heater 114 or passage 116, or through both heater 114 and passage 116.",
"The components of the heating and ventilating system 20 that have been disclosed thus far in this description of the preferred embodiment are common to many present day automobiles.",
"In the preferred form of the present invention, this conventional heating and ventilating system is modified by providing a closure valve, generally designated 120 by which the intake vent 106 is selectively closed.",
"As shown herein, this valve 120 comprises a valve plate 122 pivotally mounted to a shaft 124 positioned along the rear edge of the vent opening 106.",
"Depending from the shaft 124 and fixedly attached thereto is a lever arm 126 which in turn is attached to an actuating rod 128 of a solenoid 130.",
"Energizing the solenoid 130 retracts the rod 128 to swing the plate 128 upwardly to close the intake vent 106, while de-energizing the solenoid 130 permits this plate 128 to drop to its open position and permit inflow of outside air through the intake 106 and into the intake housing 26.",
"There are three separate switches by which the apparatus of the present invention can be activated.",
"One switch 132 is mounted proximate the closure cap 46 of the main litter removal system 30 and is activated by opening the closure cap 46 to the dotted line position shown in FIG. 2. A second switch 134 is mounted proximate the ash tray 80 or 90 and is activated by closing the ash tray to the position shown in full lines in FIG. 7 or FIG. 8. A third switch 136 is mounted on the dash board 14 and is manually operated by a person in the passenger compartment 12.",
"Each of these switches 132, 134 and 136 functions to activate the solenoid 130 to raise the valve plate 122 to close the vent opening 106.",
"There is another switch which is mounted in the solenoid 130 and closes upon activation of solenoid 130 to energize the blower motor 110 and cause the blower 108 to operate.",
"With the intake opening 106 closed by the valve plate 122, the blower 108 reduces the pressure in the intake chamber 56 to create a suction in the two suction tubes 32 and 62.",
"In operation, let it be assumed first that major litter, such as cans, napkins, etc.",
", is to be removed from the passenger compartment.",
"The closure cap 46 is swung out to its open position, and the litter is placed in the inlet 44 of the litter removal tube 30.",
"Opening of the cap 46 closes the switch 132 to energize the solenoid 130 to close the intake vent 106 by means of the plate 122 and start the blower 108 functioning.",
"This sucks air from the passenger compartment 12 through the tube 30 and into the receptacle 28, with this flow of air through the tube 30 moving the litter placed in the tube 44 into the receptacle 28.",
"A screen in the intake end of the tube 32 prevents litter from being drawn into the tube 32.",
"The litter falls to the bottom of the receptacle 28 to be removed therefrom at a later time when container 34 is emptied, as described previously herein.",
"When the closure cap 46 is released, it is spring loaded to return to its loaded position, thus opening the switch 132, to permit the plate 122 to drop to its open position and to de-energize the motor 110 to stop operation of the blower 108.",
"It has been found that while the suction force created by the blower 108 in the tube 30 is sufficient to move litter through the tube 30, this suction normally does not draw any litter from the receptacle 28 to the inlet of the suction tube 32.",
"When it is desired to empty the ash tray 80 or 90, the ash tray 80 or 90 is moved to its closed position to activate the switch 134.",
"In the same manner as described above this causes the valve plate 122 to close and activate the blower 108, thus creating a suction in the ash tray removal tube 60.",
"There is sufficient leakage around the ash tray housing to permit sufficient velocity of air flow from the passenger compartment 12 through the relatively small ash tray removal tube 60 to blow the cigar butts, cigarette butts, ashes, etc.",
", into the container 58.",
"The ash tray switch 134 is a time delay switch which remains closed for a short period of time (e.g. five to ten seconds) and then automatically opens, such as an Amperite 12 Glo Time Delay Relay.",
"Reactivation of the switch 134 is accomplished simply by opening the ash tray 80 or 90 and moving it back again to its closed position.",
"Removal of ash tray litter from the container 58 is accomplished by raising the lid 74, removing the container 58, dumping the litter and replacing the container 58 with additional scented water.",
"At the outlet of the suction tube 62, there is provided a check valve in the form of a flap 138 which opens under moderate pressure to permit flow through the tube 62 into the intake chamber 56, but which prevents any backflow, for example by some wind blowing into intake housing 56, so that ashes are not blown back through the ash tray 80 or 90 into the passenger compartment 12.",
"The ash tray litter receptacle 58 is so arranged that the litter falls to the bottom of the receptacle 58 and cannot be drawn through the top openings 72 that lead into the suction tube 62.",
"While the suction from the blower 108 is sufficient to draw the ash tray litter into the receptacle 58, this suction is not so great as to draw ash tray litter from the receptacle 58 into the intake housing 56.",
"In FIGS. 9 and 10, there is shown a modified form of the main litter disposal system of the present invention.",
"In this modified version, there is a disposal tube 150 which serves the dual function of a removal tube and a litter receptacle.",
"This tube has an inlet end 152 located adjacent the dash board 14 of the automobile 10.",
"From its inlet 152, the tube 150 has a first portion 150a which extends forwardly and generally horizontally, and a second forward section 150b which extends forwardly and downwardly in a moderate curve to a location forward of the front left wheel 154 of the automobile 10 within the body structure of the automobile.",
"The forward portion 150b of the tube 150 is curved downwardly with a moderate degree of curvature to terminate in a downwardly directed outlet opening 158.",
"The outlet 158 is closed by a cap 160 pivotally mounted at 162 to the outlet end 158 of the tube 150.",
"An operating lever 164 is rigidly connected to the cap 160 and is connected to an upstanding operating rod 166 which is urged downwardly by a compression spring assembly 168 to hold the cap 160 in its closed position.",
"The cap 160 is swung downwardly to its open position, as shown in dotted lines of FIG. 9, by lifting the rod 166 by means of a knob 170 at the top end of the rod 166.",
"When the knob 170 is released, the compression spring 168 acting on the rod 166 forces the cap 160 back to its closed position covering the forward outlet opening 158 of the tube 150.",
"There is a suction tube 172 positioned above the forward tube section 150a.",
"As in the first embodiment of the invention, the outlet end 174 of the suction tube 172 connects to the air intake housing 56 of the heating and ventilating system 26 of the automobile 10.",
"The intake end 176 of the suction tube 172 connects to tube 150 at approximately the transition area of the tube sections 150a and 150b, and communicates with the interior of the tube 150 through a plurality of holes 178 in the tube 150.",
"The manner in which the heating and ventilating system 26 functions to provide a suction in the tube 172 is the same as that described in the first embodiment of the present invention.",
"That is to say, when the inlet cap 180 for the tube 150 is opened, this closes a switch which activates the blower and closes the vent opening to create a suction which draws air into the suction tube 172.",
"In operation, when it is desired to dispose of litter, the closure cap 180 is opened to energize the system.",
"Air is drawn from the interior of the tube 150 through the holes 176 into the suction tube 172 and into the intake housing 56 of the heating and ventilating system of the automobile.",
"Since the forward outlet end 158 of the tube 150 is closed by the cap 160, there is a suction which draws air into the inlet 152 of the tube 150 to the location of the suction tube inlet 176.",
"When a bottle, napkin, or other litter is deposited into the inlet 152, it is drawn downwardly and forwardly in the tube 150.",
"As the litter reaches the forward downwardly curved portion 150b of the tube 150, normal gravity forces cause the litter to continue to the forward bottom outlet portion 158.",
"At a later time, when it is desired to remove the litter from the system, the knob 170 is operated to open the cap 160, with the accumulated litter falling from the outlet 158 of the tube 172.",
"In the event litter becomes stuck in the tube 150, high pressure air can be discharged into the tube 150 to blow the litter to the outlet end 158.",
"For this purpose, an access opening is provided in the tube 150 adjacent the automobile firewall, this opening being normally closed by a removable cap 182.",
"Another facet of the present invention is the results achieved by the proper dimensioning of the main litter removal tube, which is designated 30 in the first embodiment and 150 in the second embodiment.",
"For convenience, in describing this particular facet of the present invention, reference will be made only to the tube 30, it being understood that it is not limited to the particular configuration of that first embodiment.",
"With reference to FIG. 11, there is shown a conventional beverage container 190 in the tube 30.",
"It has been found that if the inside diameter (indicated at A in FIG. 11) of the tube 30 is made three inches, within reasonably close tolerances, the removal of common present day beverage containers, such as soft drink cans or bottles, beer bottles, etc.",
", is greatly facilitated.",
"The outside diameter (indicated at B in FIG. 11) of the common present day beverage container is between a lower value of 2 and 5/8 inches and a higher value of two and thirteen-sixteenths inches.",
"With the inside diameter of the tube 30 being just slightly larger (i.e. three-eighths of an inch to three-sixteenths of an inch) than the diameter of the beverage containers, there is sufficient clearance so that the beverage container 190 does not become caught in the tube 30, and yet the beverage container provides a sufficient obstacle to the flow of air so that it is moved along by the air stream.",
"In addition to the above, it is believed that another physical phenomenon takes place.",
"As air is sucked from the area of the tube 30 downstream of the beverage container 190, air flows forwardly around the small passageway 192 formed between the tube 30 and the container 190.",
"Since the container 190 tends to rest on the bottom of the tube 30, this passageway 192 is larger above the container 190, which results in an increased velocity of air flow above the container 190.",
"Since an increase in air velocity, according to Bernouli's law, causes a corresponding decrease in static pressure, it can reasonably be assumed that there is a pressure decrease above the container 190 which tends to lift the container 190 off the bottom of the tube 30.",
"This in turn decreases the frictional forces between the container 190 and the tube 30 which facilitates travel of the container through the tube 30.",
"Regardless of the correctness of the above theory, it has been found that proper dimensioning of the tube 30 is quite critical to the operation of the present invention.",
"For example, if the inside diameter of the tube 30 is made as great as 31/4 inches, the system is much less effective in carrying common beverage containers;",
"and if it is as small as 2 3/4 inches, there is a tendency to impede travel of the container through the tube 30."
] |
This application is a 3.71 of PCT/EP92/02882 filed Dec. 12, 1992.
BACKGROUND OF THE INVENTION
The present invention relates to the use of N-Acylphosphatidylethanolamine as anti-oxidant for unsaturated fatty acids.
Unsaturated fatty acids are broadly used compounds. They can be found in free form or chemically bound, as in triglycerides, phospholipids and sphingolipids. They are found broadly in nature and are important constituents of the food. Bound to glycerol, as triglycerides, they are present in plant seeds as energy store and are isolated from them as important basic compound for human and animal nutrition. In the phospholipids the unsaturated fatty acids are connected with all cellular membranes. In free form they are the initial products for the biological synthesis of important active products in living species, like e.g. prostaglandins. In all types of incidence the chemically unchanged form is the prerequisite for the accomplishment of the function assigned to the unsaturated fatty acids.
The most serious change is the oxygenation of the double bond in the fatty acid, with as a consequence peroxide formation and a radical chain reaction, which leads to a cleavage of the fatty acids. These reactions nay be in full control, but can also be uncontrolled. Examples of controlled oxidation are the metabolism of nutrition as energy source, the immunological resistance against bacteria and parasites and the synthesis of mediators like prostaglandins.
The radicals which are formed at the uncontrolled radical chain reaction can not only react with fatty acids but also with proteins and nucleic acids. The reaction products lead to pathological changes in the organism.
The uncontrolled oxidation is inhibited by anti-oxidants, which are taken up with the food, or are synthesised in the organism. Deficient nutrition, pathological changes and the process of ageing can lead to a deficiency in anti-oxidants.
The oxidation of consumption fats is always unwanted and leads to products, which are toxicologically unsat and which make the nutrient unpalatable by changes in the taste. These changes can be inhibited by anti-oxidants and as much as possible by the exclusion of oxygen.
Due to the large presence in different biological systems and the great importance of unsaturated fatty acids, the properties of anti-oxidants for the protection of unsaturated fatty acids are subject to various conditions. Up to now none of the known anti-oxidants fulfils the majority of these conditions.
The most used natural anti-oxidants are α-tocopherol and β-carotene are on the one hand perfectly efficacious but unstable in the presence of oxygen and light. Also the heat stability which is important in the use of some foodstuffs like oils, is limited.
Furthermore there is a complicated isolation process or a synthesis which makes the product expensive.
Ascorbic acid has the disadvantage, that it is not soluble in oils and for that matter only effective in aqueous surroundings, so that it can inhibit the oxidation of fatty acids which are present in the fat phase only to a limited extent. A further disadvantage is the fact, that ascorbic acid can be an oxidative agent in combination with iron salts.
Furthermore synthetic phosphatides as well as phosphatides isolated from plant and animal fats and oils were investigated on their anti-oxidant properties against the autoxidation of fats and oils alone and in combination with additives.
The results obtained are however strongly contradictory.
For instance is the investigation of crude lecithin and its ethanol-soluble and ethanol-insoluble fractions described by A. Nasner in Fette, Seife, Anstrichmittel 12 (1985) pp. 477-481 to determine their anti-oxidative efficacy in storage tests with sunflower oil and lard. He found, that the anti-oxidative effects depend on the type of lecithin fraction used. The ethanol-soluble fraction of the soybean lecithin with the largest portion of phosphatidylethanolamine showed the best effects. The inhibition of the oxidation of lard with a content of a-tocopherol of less than 10 ppm is markedly greater than of sunflower oil which contains 500 ppm α-tocopherol.
According to Nasner a synergy between α-tocopherol and the phosphatides can be excluded, whilst phosphatides alone provide an anti-oxidative effect.
Comparable results are obtained by D. H. Hildebrand in JAOCS 61 (1984) pp. 552 ff. in an investigation to the anti-oxidative effects of phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine. He showed, that the oil stability increases upon addition of phosphatides alone and in combination with a-tocopherol.
A synergy between the phosphatides and α-tocopherol is assumed. The best effect shows phosphatidylethanolamine, which is also confirmed by I. S. Bhatia et al. in J. Sci. Fd. Agric. 79 (1978) pp. 77 ff.
Other investigations are in contrast with these investigations. J. H. Lee et al describe for instance in the Bulletin of the Japanese Society of Scientific Fisheries 47 (1981) pp. 881-883 the anti-oxidative effects of lipids of the Antarctic shrimp. In these investigations α-tocopherol was identified as the active substance, whereas only a synergistic effect was attributed to the phosphatides in respect to the improvement of the effects of α-tocopherol.
J. H. Lee et al in J. Biol. Chem. 47 (1983) pp. 2001 ff. investigated the anti-oxidative properties of phosphatide fractions from shrimp, egg yolk and soybeans and observed, that these fractions do not provide an anti-oxidative effect, but activate the decomposition of the peroxides formed by oxidation.
M. Kashima et al. in JAOCS 68 (1991 ) pp. 119 ff. also deny the anti-oxidative effect of phosphatides as phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine. The anti-oxidative effects of these phosphatides were determined in tocopherol-free perila oil and the same oil with an increased content in tocopherol. It was observed, that the oxidative stability of the tocopherol-free perila oil was not improved by the addition of the phosphatides, whereas on the other hand the oxidation of the perila oil with the increased content in tocopherol was strongly suppressed by the addition of phosphatidylethanolamine and phosphatidylserine. This confirms earlier results, that phosphatides alone do not provide an anti-oxidative effect, but only increase the anti-oxidative effect of α-tocopherol due to a synergistic mechanism.
Other natural anti-oxidants are plant extracts. like for instance extracts from rosemary. The disadvantages of such products are the natural variations of their composition. They often contain dyes, have an unwanted taste and smell and are difficult to obtain.
Anti-oxidants not obtained from natural sources, like BHA, BHT, TBHQ and propyl gallate all contain a sterically hindered phenyl moiety and are, as all phenols in biological systems, reactive. Investigations in recent years have shown, that BHA may cause cancer at certain concentrations in different animal species. For that reason BHA-containing foodstuffs must be marked with the text "BHA may lead to cancer, unless certain concentrations are kept" in some countries. Also the increasing awareness of environmental problems in the population has led to a steady decline in the acceptance of unnatural products in foodstuffs.
SUMMARY OF THE INVENTION
The aim of the present invention was to provide a product, which inhibits or at least strongly reduces the oxidative decomposition of unsaturated fatty acids in free or bound form and does not show the disadvantages of the anti-oxidants presently in use.
This aim is reached by the use of N-acylphosphatidylethanolamine as anti-oxidant for products containing unsaturated fatty acids and their derivatives.
DETAILED DESCRIPTION OF THE INVENTION
N-acylphosphatidylethanolamines are known compounds, the occurrence in the nature of which was investigated in depth by J. L. Newman in Chem. Phys. Lipids 42 (1986) pp 249 ff. This type of product was found in micro-organisms, plants, tissue of vertebrates like e.g. the myocardium or the epidermis, as well as in amoebae and plant seedlings.
It was a surprise, especially in respect with the contrasting results of the investigations of related products to their anti-oxidative effect, that N-acylphosphatidylethanolamines can protect unsaturated fatty acids in free as well as in bound form against oxidative decomposition.
This product group furthermore provides several advantages in comparison with the anti-oxidants used up to now:
These compounds are present in humans, animal and plant organisms and are toxicologically safe.
They build barriers in the form of bilayers in analogy to biological membranes and are dispersible in water as well as soluble in lipid.
Their stability in the presence of oxygen and light is greater than that of α-tocopherol.
The N-acyl phosphatidylethanolamines used according to the invention can be synthesised according to DE-A-27 56 866 (U.S. Pat. No. 4,254,115) by the reaction of phosphatidylethanolamine with acid chlorides or acid anhydrides.
Chemically pure phosphatidylethanolamine can be isolated from ethanol insoluble soybean lecithin fractions, which are usually rich in phosphatidylethanolamine. Preparative chromatographic separation methods allow the production of pure products for the reaction with acid anhydrides.
Determination of the efficacy of N-acylphosphatidylethanolamines.
The oxidative decomposition of compounds containing unsaturated fatty acids goes according to different reaction mechanisms, whereby the oxidative agents may differ. To prove the efficacy of the N-acylphosphatidylethanolamines soybean N-acylphosphatidylethanolamine (NACPE), soybean N-acetylphosphatidylethanolamine (NATPE) and soybean-N-oleoylphosphatidylethanolamine (NOLPE) were investigated in four different test systems.
EXAMPLE 1
Synthesis of NOLPE
100 g chemically pure phosphatidylethanolamine was produced by a column-chromatographic separation of an alcohol-insoluble soybean lecithin fraction rich in phosphatidylethanolamine on silica gel with chloroform/methanol as eluent. The product is dissolved in 500 ml toluene and is reacted after the addition of 38 ml triethylamine with a solution of 41.2 g oleic acid chloride in 60 ml toluene under stirring. After stirring for one hour at room temperature the sedimented triethylamine chloride is filtered off and the solvent removed in vacuum at a bath temperature of 60° C. under nitrogen. The residue is N-Oleoylphosphatidylethanolamine in the form of a viscous brown oil.
Yield 115 g=96% of the theory.
Synthesis of NATPE
The synthesis of NATPE is performed analogously by the reaction of 100 g chemically pure phosphatidylethanolamine with 14 g acetic anhydride.
Yield 100.1 g=97% of the theory.
Synthesis of NACPE
The synthesis of NACPE is performed analogously by the reaction of chemically pure phosphatidylethanolamine with mixtures of fatty acid chlorides, which are gained by the chlorination of fatty acid mixtures from soybeans, palm oil or sunflower oil.
Oxidative agent 1: cumene hydroperoxide (CHP)
(A. Sevanian in Lipid Peroxidation (1988) pp. 84-99)
______________________________________Method 1:______________________________________100 umol/l cumene hydroperoxide40 umol/l FeCl.sub.2 as oxidative agent and100 ug substrate (for instance linoleic acid)______________________________________
are dissolved in 2.5 ml water with 10 mmol/l tris buffer at pH 7.4.
The substances to be used according to the invention were added in increasing concentrations from 0.01 to 5% by weight relative to the substrate.
The control sample does not contain additives. After an incubation period of 1 h at 37° C. the change induced by the oxidative decomposition was determined.
______________________________________Method 2.______________________________________1 g plant oil100 ul cumene hydroperoxide (184 ul in 10 ml ethanol)10 ul FeCl.sub.2 (0,2 mmol/l)______________________________________
are incubated for 1 h at 37° C.
This system is the most frequently used model to measure radical oxidations under controlled conditions in vitro.
Oxidative agent 2: UVA light irradiation
(K. J. Denis & T. Shibamoto: Lipids 25 (1090) pp. 460-464)
______________________________________Source: fluorescent lamp Philips TL/10Radiation time: 1 hQuantity: 100 ug substrate______________________________________
The substrate and the inventive anti-oxidants are dispersed in 2 ml water which leads to the formation of micelles with the fatty acids and the formation of liposomes with the phospholipids and the sample is irradiated.
This oxidation model is the model of choice for the light-induced radical reactions.
Oxidative agent 3: Lipoxygenase (LOG)
(H. Aochima; Anal. Biochem. 25 (1978) pp. 49-55)
A reaction sample contains in 3 ml of
______________________________________0.1 mol/l potassium borate buffer pH 8.0:______________________________________1500 U/ml soybean lipoxygenase type I (Sigma)100 ug substrate______________________________________
Duration of incubation: 1 h at 37° C.
This reaction allows the evaluation of enzymatically induced peroxidations under controlled conditions.
Oxidative agent 4: superoxide (SPO)
(T. C. Pederson, S. D. Aust; Biochem. Biophys. Res. Comm. 52 (1973) pp. 1071-1078;
M. Tien, B. A. Svingen & S. D. Aust;
Federation Proceedings 40 (1981) pp. 179-182)
______________________________________Method:______________________________________0.33 mol/l xanthine0.10 IU xanthine oxidase0.10 mmol/l FeCl.sub.30.11 mmol/l EDTA0.20 mmol/l ADP100 ug substrate______________________________________
are suspended in 0.3 mmol/l NaCl solution and incubated for 1 h at 37° C.
This oxidation system allows the in vitro investigation of anti-oxidants, the mode of action of which is assumed to be at the peroxidation in the respiration cycle of cells.
The inventive substances were added in the following concentrations as % by weight relative to the substrate:
0% (control), 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%.
After termination of the incubation the degree of the oxidative decomposition is quantified according to the following criteria:
decreased concentration in linoleic acid (investigative method 1)
increase in malondialdehyde as main decomposition product of linoleic acid (investigative method 2).
Method of investigation 1.
Determination by gas chromatograph of the change in substrate concentration
The determination of the peroxidation is performed indirectly by the determination of the loss of linoleic acid. To make corrections for losses due to the sampling palmitic acid is added to the solution to be peroxidised and the quotient C16/C18 determined.
______________________________________Gas chromatograph conditions:______________________________________column DB-225, 25 m; 150-220 °C.: 3°/mindetector: FIDcarrier gas: hydrogen______________________________________
For the gas chromatographic analysis the fatty acids are reacted with boron trifluoride to the methyl esters.
Method of investigation 2.
(V. C. Tatam, C. C. Chongchit & C. K. Chow; Lipids 25 (1990) pp. 226-229;
H. Y. Wong et al.; Clin. Chem. 33 (1987) 214-220;
J. A. Knight et al.; Clin. Chem. 34 (1988) pp. 1197-12110)
Malondialdehyde determination
______________________________________Formation of malondialdehyde______________________________________0.1-0.5 ml of the respective reaction sample+0.5 ml thiobarbituric acid reagent (2 parts 0.4% TBA in 0.2 N HCl + 1 part water)+0.07 ml 0.2% BHT in ethanol______________________________________
Thereafter 45 min in a water bath of 90° C. Thereafter extraction of the TBA-MDA adduct with isobutanol. The isobutanol extract is subsequently mixed with methanol (2:1) and injected into the HPLC.
______________________________________HPLC separation______________________________________eluent: methanol/water 1: 10.05 % tetrabutylammoniumhydrogen sulphatecolumn: Lichrospher 100 RP-18 5 um 125 × 4 mmdetection: fluorescence EX 515 nm Em: 550 nmelution speed: 1 ml/minStandard plot made with 1,1,3,3 -tetrahydroxypropane.______________________________________
The results illustrating the anti-oxidative efficacy of the inventive N-acylphosphatidylethanolamines are summarised in tables 1 to 7.
In comparison to the efficacy of the inventive compounds, investigations were performed with tocopherol (vitamin E). These data have been summarised as tables 8 to 11.
The values in the tables represent the absolute values, obtained with the respective method as well as the percent change, the value of the control sample without anti-oxidant being taken as 100%.
______________________________________Abbreviations used.______________________________________1. soybean N-acylphosphatidylethanolamine NACPE2. soybean N-acetylphosphatidylethanolamine NATPE3. soybean N-oleoylphosphatidylethanolamine NOLPE4. cumene hydroperoxide CHP5. UVA light irradiation UVA6. lipoxygenase LOG7. superoxide SPO8. d,1-tocopherol TOC9. gamma linoleic acid GLA10. soybean phosphatidylcholine SPC11. bovine brain phosphatidylethanolamine HPE12. triglycerides from evening primrose TRG______________________________________
TABLE 1______________________________________ substrate: GLANACPE oxidative agent LOGconcentration method: 1% by weight absolute %______________________________________0 2.9 1000.01 0.7 240.05 0.8 280.1 0.6 210.5 0.6 211 0.7 245 0.8 28______________________________________
TABLE 2______________________________________ substrate: GLANATPE oxidative agent: UVAconcentration method: 1% by weight absolute %______________________________________0 3.2 1000.01 0.4 130.05 0.4 130.1 0.5 160.5 0,5 161 0.4 135 0.5 16______________________________________
TABLE 3______________________________________ substrate: GLANOLPE oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 3.6 1000.01 1.2 330.05 1.3 360.1 1.1 310.5 1,1 311 1.2 335 1.2 33______________________________________
TABLE 4______________________________________ substrate: SPCNATPE oxidative agent: CHPconcentration method: 1% by weight absolute %______________________________________0 2.4 1000.01 1.0 410.05 0.9 380.1 0.8 330.5 0.7 291 0.8 335 0.8 33______________________________________
TABLE 5______________________________________ substrate: HPENOLPE oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 2.0 1000.01 0.8 400.05 0.8 400.1 0.8 400.5 0.8 401 0.9 455 0.9 45______________________________________
TABLE 6______________________________________ substrate: HPENACPE oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 2.8 1000.01 1.4 500.05 1.3 400.1 1.2 400.5 0.9 401 1.3 455 1.6 45______________________________________
TABLE 7______________________________________ substrate: HPENATPE oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 2.4 1000.01 1.9 790.05 1.7 710.1 1.2 500.5 1.3 541 1.4 585 1.8 75______________________________________
The following determinations were comparative investigations performed with α-tocopherol.
TABLE 8______________________________________ substrate: GLATOC oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 3.6 1000.01 1.0 280.05 0.8 220.1 0.6 170.5 0.7 191 0.7 195 0.7 19______________________________________
TABLE 9______________________________________ substrate: GLATOC oxidative agent: LOGconcentration method: 1% by weight absolute %______________________________________0 2.9 1000.01 0.6 210.05 0.6 210.1 0.5 170.5 0.5 171 0.7 245 0.6 21______________________________________
TABLE 10______________________________________ substrate: HPENACPE oxidative agent: CHPconcentration method: 1% by weight absolute %______________________________________0 2.4 1000.01 0.8 330.05 0.7 300.1 0.7 300.5 0.7 301 0.8 335 0.7 30______________________________________
TABLE 11______________________________________ substrate: TRGTOC oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 2.4 1000.01 1.3 540.05 1.0 420.1 1.0 420.5 0.7 291 0.8 335 0.8 33______________________________________ | A method of inhibiting oxidation of products containing unsaturated fatty acids and their derivatives comprises treating the unsaturated fatty acids and their derivatives with N-acylphosphatidylethanolamines. Preferred N-acylphosphatidylethanolamines are N-acetylphosphatidylethanolamine and N-oleoylphosphatidylethanolamine. | Briefly describe the main idea outlined in the provided context. | [
"This application is a 3.71 of PCT/EP92/02882 filed Dec. 12, 1992.",
"BACKGROUND OF THE INVENTION The present invention relates to the use of N-Acylphosphatidylethanolamine as anti-oxidant for unsaturated fatty acids.",
"Unsaturated fatty acids are broadly used compounds.",
"They can be found in free form or chemically bound, as in triglycerides, phospholipids and sphingolipids.",
"They are found broadly in nature and are important constituents of the food.",
"Bound to glycerol, as triglycerides, they are present in plant seeds as energy store and are isolated from them as important basic compound for human and animal nutrition.",
"In the phospholipids the unsaturated fatty acids are connected with all cellular membranes.",
"In free form they are the initial products for the biological synthesis of important active products in living species, like e.g. prostaglandins.",
"In all types of incidence the chemically unchanged form is the prerequisite for the accomplishment of the function assigned to the unsaturated fatty acids.",
"The most serious change is the oxygenation of the double bond in the fatty acid, with as a consequence peroxide formation and a radical chain reaction, which leads to a cleavage of the fatty acids.",
"These reactions nay be in full control, but can also be uncontrolled.",
"Examples of controlled oxidation are the metabolism of nutrition as energy source, the immunological resistance against bacteria and parasites and the synthesis of mediators like prostaglandins.",
"The radicals which are formed at the uncontrolled radical chain reaction can not only react with fatty acids but also with proteins and nucleic acids.",
"The reaction products lead to pathological changes in the organism.",
"The uncontrolled oxidation is inhibited by anti-oxidants, which are taken up with the food, or are synthesised in the organism.",
"Deficient nutrition, pathological changes and the process of ageing can lead to a deficiency in anti-oxidants.",
"The oxidation of consumption fats is always unwanted and leads to products, which are toxicologically unsat and which make the nutrient unpalatable by changes in the taste.",
"These changes can be inhibited by anti-oxidants and as much as possible by the exclusion of oxygen.",
"Due to the large presence in different biological systems and the great importance of unsaturated fatty acids, the properties of anti-oxidants for the protection of unsaturated fatty acids are subject to various conditions.",
"Up to now none of the known anti-oxidants fulfils the majority of these conditions.",
"The most used natural anti-oxidants are α-tocopherol and β-carotene are on the one hand perfectly efficacious but unstable in the presence of oxygen and light.",
"Also the heat stability which is important in the use of some foodstuffs like oils, is limited.",
"Furthermore there is a complicated isolation process or a synthesis which makes the product expensive.",
"Ascorbic acid has the disadvantage, that it is not soluble in oils and for that matter only effective in aqueous surroundings, so that it can inhibit the oxidation of fatty acids which are present in the fat phase only to a limited extent.",
"A further disadvantage is the fact, that ascorbic acid can be an oxidative agent in combination with iron salts.",
"Furthermore synthetic phosphatides as well as phosphatides isolated from plant and animal fats and oils were investigated on their anti-oxidant properties against the autoxidation of fats and oils alone and in combination with additives.",
"The results obtained are however strongly contradictory.",
"For instance is the investigation of crude lecithin and its ethanol-soluble and ethanol-insoluble fractions described by A. Nasner in Fette, Seife, Anstrichmittel 12 (1985) pp. 477-481 to determine their anti-oxidative efficacy in storage tests with sunflower oil and lard.",
"He found, that the anti-oxidative effects depend on the type of lecithin fraction used.",
"The ethanol-soluble fraction of the soybean lecithin with the largest portion of phosphatidylethanolamine showed the best effects.",
"The inhibition of the oxidation of lard with a content of a-tocopherol of less than 10 ppm is markedly greater than of sunflower oil which contains 500 ppm α-tocopherol.",
"According to Nasner a synergy between α-tocopherol and the phosphatides can be excluded, whilst phosphatides alone provide an anti-oxidative effect.",
"Comparable results are obtained by D. H. Hildebrand in JAOCS 61 (1984) pp. 552 ff.",
"in an investigation to the anti-oxidative effects of phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine.",
"He showed, that the oil stability increases upon addition of phosphatides alone and in combination with a-tocopherol.",
"A synergy between the phosphatides and α-tocopherol is assumed.",
"The best effect shows phosphatidylethanolamine, which is also confirmed by I. S. Bhatia et al.",
"in J. Sci.",
"Fd.",
"Agric.",
"79 (1978) pp. 77 ff.",
"Other investigations are in contrast with these investigations.",
"J. H. Lee et al describe for instance in the Bulletin of the Japanese Society of Scientific Fisheries 47 (1981) pp. 881-883 the anti-oxidative effects of lipids of the Antarctic shrimp.",
"In these investigations α-tocopherol was identified as the active substance, whereas only a synergistic effect was attributed to the phosphatides in respect to the improvement of the effects of α-tocopherol.",
"J. H. Lee et al in J. Biol.",
"Chem.",
"47 (1983) pp. 2001 ff.",
"investigated the anti-oxidative properties of phosphatide fractions from shrimp, egg yolk and soybeans and observed, that these fractions do not provide an anti-oxidative effect, but activate the decomposition of the peroxides formed by oxidation.",
"M. Kashima et al.",
"in JAOCS 68 (1991 ) pp. 119 ff.",
"also deny the anti-oxidative effect of phosphatides as phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine.",
"The anti-oxidative effects of these phosphatides were determined in tocopherol-free perila oil and the same oil with an increased content in tocopherol.",
"It was observed, that the oxidative stability of the tocopherol-free perila oil was not improved by the addition of the phosphatides, whereas on the other hand the oxidation of the perila oil with the increased content in tocopherol was strongly suppressed by the addition of phosphatidylethanolamine and phosphatidylserine.",
"This confirms earlier results, that phosphatides alone do not provide an anti-oxidative effect, but only increase the anti-oxidative effect of α-tocopherol due to a synergistic mechanism.",
"Other natural anti-oxidants are plant extracts.",
"like for instance extracts from rosemary.",
"The disadvantages of such products are the natural variations of their composition.",
"They often contain dyes, have an unwanted taste and smell and are difficult to obtain.",
"Anti-oxidants not obtained from natural sources, like BHA, BHT, TBHQ and propyl gallate all contain a sterically hindered phenyl moiety and are, as all phenols in biological systems, reactive.",
"Investigations in recent years have shown, that BHA may cause cancer at certain concentrations in different animal species.",
"For that reason BHA-containing foodstuffs must be marked with the text "BHA may lead to cancer, unless certain concentrations are kept"",
"in some countries.",
"Also the increasing awareness of environmental problems in the population has led to a steady decline in the acceptance of unnatural products in foodstuffs.",
"SUMMARY OF THE INVENTION The aim of the present invention was to provide a product, which inhibits or at least strongly reduces the oxidative decomposition of unsaturated fatty acids in free or bound form and does not show the disadvantages of the anti-oxidants presently in use.",
"This aim is reached by the use of N-acylphosphatidylethanolamine as anti-oxidant for products containing unsaturated fatty acids and their derivatives.",
"DETAILED DESCRIPTION OF THE INVENTION N-acylphosphatidylethanolamines are known compounds, the occurrence in the nature of which was investigated in depth by J. L. Newman in Chem.",
"Phys.",
"Lipids 42 (1986) pp 249 ff.",
"This type of product was found in micro-organisms, plants, tissue of vertebrates like e.g. the myocardium or the epidermis, as well as in amoebae and plant seedlings.",
"It was a surprise, especially in respect with the contrasting results of the investigations of related products to their anti-oxidative effect, that N-acylphosphatidylethanolamines can protect unsaturated fatty acids in free as well as in bound form against oxidative decomposition.",
"This product group furthermore provides several advantages in comparison with the anti-oxidants used up to now: These compounds are present in humans, animal and plant organisms and are toxicologically safe.",
"They build barriers in the form of bilayers in analogy to biological membranes and are dispersible in water as well as soluble in lipid.",
"Their stability in the presence of oxygen and light is greater than that of α-tocopherol.",
"The N-acyl phosphatidylethanolamines used according to the invention can be synthesised according to DE-A-27 56 866 (U.S. Pat. No. 4,254,115) by the reaction of phosphatidylethanolamine with acid chlorides or acid anhydrides.",
"Chemically pure phosphatidylethanolamine can be isolated from ethanol insoluble soybean lecithin fractions, which are usually rich in phosphatidylethanolamine.",
"Preparative chromatographic separation methods allow the production of pure products for the reaction with acid anhydrides.",
"Determination of the efficacy of N-acylphosphatidylethanolamines.",
"The oxidative decomposition of compounds containing unsaturated fatty acids goes according to different reaction mechanisms, whereby the oxidative agents may differ.",
"To prove the efficacy of the N-acylphosphatidylethanolamines soybean N-acylphosphatidylethanolamine (NACPE), soybean N-acetylphosphatidylethanolamine (NATPE) and soybean-N-oleoylphosphatidylethanolamine (NOLPE) were investigated in four different test systems.",
"EXAMPLE 1 Synthesis of NOLPE 100 g chemically pure phosphatidylethanolamine was produced by a column-chromatographic separation of an alcohol-insoluble soybean lecithin fraction rich in phosphatidylethanolamine on silica gel with chloroform/methanol as eluent.",
"The product is dissolved in 500 ml toluene and is reacted after the addition of 38 ml triethylamine with a solution of 41.2 g oleic acid chloride in 60 ml toluene under stirring.",
"After stirring for one hour at room temperature the sedimented triethylamine chloride is filtered off and the solvent removed in vacuum at a bath temperature of 60° C. under nitrogen.",
"The residue is N-Oleoylphosphatidylethanolamine in the form of a viscous brown oil.",
"Yield 115 g=96% of the theory.",
"Synthesis of NATPE The synthesis of NATPE is performed analogously by the reaction of 100 g chemically pure phosphatidylethanolamine with 14 g acetic anhydride.",
"Yield 100.1 g=97% of the theory.",
"Synthesis of NACPE The synthesis of NACPE is performed analogously by the reaction of chemically pure phosphatidylethanolamine with mixtures of fatty acid chlorides, which are gained by the chlorination of fatty acid mixtures from soybeans, palm oil or sunflower oil.",
"Oxidative agent 1: cumene hydroperoxide (CHP) (A.",
"Sevanian in Lipid Peroxidation (1988) pp. 84-99) ______________________________________Method 1:______________________________________100 umol/l cumene hydroperoxide40 umol/l FeCl.",
"sub[.",
"].2 as oxidative agent and100 ug substrate (for instance linoleic acid)______________________________________ are dissolved in 2.5 ml water with 10 mmol/l tris buffer at pH 7.4.",
"The substances to be used according to the invention were added in increasing concentrations from 0.01 to 5% by weight relative to the substrate.",
"The control sample does not contain additives.",
"After an incubation period of 1 h at 37° C. the change induced by the oxidative decomposition was determined.",
"______________________________________Method 2.",
"______________________________________1 g plant oil100 ul cumene hydroperoxide (184 ul in 10 ml ethanol)10 ul FeCl.",
"sub[.",
"].2 (0,2 mmol/l)______________________________________ are incubated for 1 h at 37° C. This system is the most frequently used model to measure radical oxidations under controlled conditions in vitro.",
"Oxidative agent 2: UVA light irradiation (K.",
"J. Denis &",
"T. Shibamoto: Lipids 25 (1090) pp. 460-464) ______________________________________Source: fluorescent lamp Philips TL/10Radiation time: 1 hQuantity: 100 ug substrate______________________________________ The substrate and the inventive anti-oxidants are dispersed in 2 ml water which leads to the formation of micelles with the fatty acids and the formation of liposomes with the phospholipids and the sample is irradiated.",
"This oxidation model is the model of choice for the light-induced radical reactions.",
"Oxidative agent 3: Lipoxygenase (LOG) (H.",
"Aochima;",
"Anal.",
"Biochem.",
"25 (1978) pp. 49-55) A reaction sample contains in 3 ml of ______________________________________0.1 mol/l potassium borate buffer pH 8.0:______________________________________1500 U/ml soybean lipoxygenase type I (Sigma)100 ug substrate______________________________________ Duration of incubation: 1 h at 37° C. This reaction allows the evaluation of enzymatically induced peroxidations under controlled conditions.",
"Oxidative agent 4: superoxide (SPO) (T.",
"C. Pederson, S. D. Aust;",
"Biochem.",
"Biophys.",
"Res.",
"Comm.",
"52 (1973) pp. 1071-1078;",
"M. Tien, B. A. Svingen &",
"S. D. Aust;",
"Federation Proceedings 40 (1981) pp. 179-182) ______________________________________Method:______________________________________0.33 mol/l xanthine0.10 IU xanthine oxidase0.10 mmol/l FeCl.",
"sub[.",
"].30.11 mmol/l EDTA0.20 mmol/l ADP100 ug substrate______________________________________ are suspended in 0.3 mmol/l NaCl solution and incubated for 1 h at 37° C. This oxidation system allows the in vitro investigation of anti-oxidants, the mode of action of which is assumed to be at the peroxidation in the respiration cycle of cells.",
"The inventive substances were added in the following concentrations as % by weight relative to the substrate: 0% (control), 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%.",
"After termination of the incubation the degree of the oxidative decomposition is quantified according to the following criteria: decreased concentration in linoleic acid (investigative method 1) increase in malondialdehyde as main decomposition product of linoleic acid (investigative method 2).",
"Method of investigation 1.",
"Determination by gas chromatograph of the change in substrate concentration The determination of the peroxidation is performed indirectly by the determination of the loss of linoleic acid.",
"To make corrections for losses due to the sampling palmitic acid is added to the solution to be peroxidised and the quotient C16/C18 determined.",
"______________________________________Gas chromatograph conditions:______________________________________column DB-225, 25 m;",
"150-220 °C.",
": 3°/mindetector: FIDcarrier gas: hydrogen______________________________________ For the gas chromatographic analysis the fatty acids are reacted with boron trifluoride to the methyl esters.",
"Method of investigation 2.",
"(V.",
"C. Tatam, C. C. Chongchit &",
"C. K. Chow;",
"Lipids 25 (1990) pp. 226-229;",
"H. Y. Wong et al.",
"Clin.",
"Chem.",
"33 (1987) 214-220;",
"J. A. Knight et al.",
"Clin.",
"Chem.",
"34 (1988) pp. 1197-12110) Malondialdehyde determination ______________________________________Formation of malondialdehyde______________________________________0.1-0.5 ml of the respective reaction sample+0.5 ml thiobarbituric acid reagent (2 parts 0.4% TBA in 0.2 N HCl + 1 part water)+0.07 ml 0.2% BHT in ethanol______________________________________ Thereafter 45 min in a water bath of 90° C. Thereafter extraction of the TBA-MDA adduct with isobutanol.",
"The isobutanol extract is subsequently mixed with methanol (2:1) and injected into the HPLC.",
"______________________________________HPLC separation______________________________________eluent: methanol/water 1: 10.05 % tetrabutylammoniumhydrogen sulphatecolumn: Lichrospher 100 RP-18 5 um 125 × 4 mmdetection: fluorescence EX 515 nm Em: 550 nmelution speed: 1 ml/minStandard plot made with 1,1,3,3 -tetrahydroxypropane.",
"______________________________________ The results illustrating the anti-oxidative efficacy of the inventive N-acylphosphatidylethanolamines are summarised in tables 1 to 7.",
"In comparison to the efficacy of the inventive compounds, investigations were performed with tocopherol (vitamin E).",
"These data have been summarised as tables 8 to 11.",
"The values in the tables represent the absolute values, obtained with the respective method as well as the percent change, the value of the control sample without anti-oxidant being taken as 100%.",
"______________________________________Abbreviations used.",
"______________________________________1.",
"soybean N-acylphosphatidylethanolamine NACPE2.",
"soybean N-acetylphosphatidylethanolamine NATPE3.",
"soybean N-oleoylphosphatidylethanolamine NOLPE4.",
"cumene hydroperoxide CHP5.",
"UVA light irradiation UVA6.",
"lipoxygenase LOG7.",
"superoxide SPO8.",
"d,1-tocopherol TOC9.",
"gamma linoleic acid GLA10.",
"soybean phosphatidylcholine SPC11.",
"bovine brain phosphatidylethanolamine HPE12.",
"triglycerides from evening primrose TRG______________________________________ TABLE 1______________________________________ substrate: GLANACPE oxidative agent LOGconcentration method: 1% by weight absolute %______________________________________0 2.9 1000.01 0.7 240.05 0.8 280.1 0.6 210.5 0.6 211 0.7 245 0.8 28______________________________________ TABLE 2______________________________________ substrate: GLANATPE oxidative agent: UVAconcentration method: 1% by weight absolute %______________________________________0 3.2 1000.01 0.4 130.05 0.4 130.1 0.5 160.5 0,5 161 0.4 135 0.5 16______________________________________ TABLE 3______________________________________ substrate: GLANOLPE oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 3.6 1000.01 1.2 330.05 1.3 360.1 1.1 310.5 1,1 311 1.2 335 1.2 33______________________________________ TABLE 4______________________________________ substrate: SPCNATPE oxidative agent: CHPconcentration method: 1% by weight absolute %______________________________________0 2.4 1000.01 1.0 410.05 0.9 380.1 0.8 330.5 0.7 291 0.8 335 0.8 33______________________________________ TABLE 5______________________________________ substrate: HPENOLPE oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 2.0 1000.01 0.8 400.05 0.8 400.1 0.8 400.5 0.8 401 0.9 455 0.9 45______________________________________ TABLE 6______________________________________ substrate: HPENACPE oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 2.8 1000.01 1.4 500.05 1.3 400.1 1.2 400.5 0.9 401 1.3 455 1.6 45______________________________________ TABLE 7______________________________________ substrate: HPENATPE oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 2.4 1000.01 1.9 790.05 1.7 710.1 1.2 500.5 1.3 541 1.4 585 1.8 75______________________________________ The following determinations were comparative investigations performed with α-tocopherol.",
"TABLE 8______________________________________ substrate: GLATOC oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 3.6 1000.01 1.0 280.05 0.8 220.1 0.6 170.5 0.7 191 0.7 195 0.7 19______________________________________ TABLE 9______________________________________ substrate: GLATOC oxidative agent: LOGconcentration method: 1% by weight absolute %______________________________________0 2.9 1000.01 0.6 210.05 0.6 210.1 0.5 170.5 0.5 171 0.7 245 0.6 21______________________________________ TABLE 10______________________________________ substrate: HPENACPE oxidative agent: CHPconcentration method: 1% by weight absolute %______________________________________0 2.4 1000.01 0.8 330.05 0.7 300.1 0.7 300.5 0.7 301 0.8 335 0.7 30______________________________________ TABLE 11______________________________________ substrate: TRGTOC oxidative agent: CHPconcentration method: 2% by weight absolute %______________________________________0 2.4 1000.01 1.3 540.05 1.0 420.1 1.0 420.5 0.7 291 0.8 335 0.8 33______________________________________"
] |
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a fixing apparatus (device) which is mounted in an image forming apparatus such as an electrophotographic copying machine, an electrophotographic printer, etc.
A fixing apparatus (fixing device) which is to be mounted in an electrophotographic copying machine, an electrophotographic printer, and the like is desired to start up as quickly as possible, and also, to be as small in energy consumption as possible. Thus, a fixing device which employs a fixing belt has been put to practical use. A fixing device of this type has: a cylindrical fixation belt; a belt backing member, which is disposed on the inward side of the fixation belt loop; a pressure roller which forms a nip by being pressed against the belt backing member with the placement of the fixation belt between itself and belt backing member; etc. A sheet of recording medium which is bearing an unfixed toner image is conveyed through the nip while being heated in the nip. Thus, the toner image on the sheet P of recording medium becomes fixed to the sheet of recording medium.
There are various methods for heating a fixation belt. For example, there are a heating method which employs a heat generating flat member such as a ceramic heater, a heating method which employs a heating means based on electromagnetic induction, and the like, which are proposed in Japanese Laid-open Patent application No. 2009-98357, Japanese Patent No. 3,807,223, and Japanese Laid-open Patent Application No. H10-321352.
However, a fixing device, such as the one describe above, which employs a belt backing member to form a nip, is problematic in that it is likely to output a defective image, the defect of which is referred to as “cracking”.
FIG. 16 is a magnified image of a “cracked” image, which was obtained with the use of a microscope. This “cracked” image was outputted by a fixing device, which employs a fixation belt, when the fixing device was used to fix a solid monochromatic image of cyan color to a sheet of recording paper (which hereafter may be referred to simply as sheet of paper). As is evident from FIG. 16 , “cracking” is an image defect attributable to a phenomenon that as the toner particles, of which an unfixed image on a sheet of recording medium (paper) shift in position, the portions of the sheet, which were under the toner particles, become exposed. The primary cause of this image defect is the “wrinkles” which occur to the outward surface layer (parting layer) of a fixation belt. That is, the “wrinkles” are attributable to the displacement of the unfixed toner particles by the wrinkling of the outward surface layer of the fixation belt.
It is on the upstream side of the fixation nip, in terms of the recording medium conveyance direction in the fixation nip, that the toner particle displacement occurs. As for the reason for the toner particle displacement, when a given portion of a sheet of paper, on which an unfixed toner image is present, is in the upstream portion of the fixation nip, the toner particles on this portion of the sheet, will not have substantially melted. Therefore, they are weak in their adhesiveness to the sheet, and in the adhesiveness among them in this portion of the sheet. Therefore, they are likely to be shifted in position by the wrinkling of the outward surface layer of the fixation belt. In comparison, in the downstream side of the fixation nip in terms of the recording medium conveyance direction, the toner particles on the sheet will have substantially melted. Therefore, even if the outward surface layer of the fixation belt is wrinkled, it hardly occurs that the toner particles are displaced by the wrinkling of the outward surface layer of the fixation roller.
The “wrinkling” of the outward surface layer of a fixation belt occurs as the outward surface layer of the fixation belt is compressed in such a manner that the outward surface is concavely bent, or it becomes flat. As will be described later, as a given portion of a fixation belt, in terms of the moving direction of the fixation belt, is moved into a fixation nip, it is deformed by the combination of a belt backing member, and a pressure roller, against which the fixation belt is pressed by the belt backing member. Thus, in terms of its vertical cross-section, which is parallel to the moving direction of the fixation belt, the shape of the portion of the fixation belt in the fixation nip is determined by the shape of the belt backing member. Thus, as the outward surface layer of the fixation belt is changed in shape by the belt backing member as described above, wrinkles occur to the outward surface layer of the fixation belt.
Next, referring to FIGS. 17( a ), 17 ( b ) and 17 ( c ), the mechanism of the wrinkling of the outward surface layer of the fixation belt is described. FIG. 17( a ) is a schematic cross-sectional view of a section of the fixation belt, when the fixation belt is under no pressure. In FIG. 17( a ), the portion outlined by a solid line (which corresponds to angle θ) is equivalent to the portion of the fixation belt, which is in the fixation nip when the fixation belt is under the pressure.
Referring to FIG. 17( a ), referential codes Le and Li stand for the length of the outward and inward surfaces, respectively, of the portion of the surface layers of the fixation layer in the fixation nip. Referential codes Re and Ri stand for the radius of the outward surface of the outward surface layer of the fixation belt, and the inward surface of the fixation belt, respectively. Further, a referential code W stands for the thickness of the fixation belt (W=Re−Ri).
FIG. 17( b ) is a schematic cross-sectional view of the portion of the fixation belt, which is shown in FIG. 17( a ), when the portion is in the fixation nip, having thereby been flattened by being pressed upon an unshown belt backing member by an unshown pressure roller. In FIG. 17( b ), referential codes Le′ and Li′ stand for the length of the outward surface of the portion outlined by the solid line, and the length of the inward surface of the portion outlined by the solid line, respectively. The length Le′ has no direct relation to the wrinkling of the portion. It is the direct distance between points A and B in FIG. 17( b ) that has direct relationship to the wrinkling.
FIG. 17( c ) is a schematic cross-sectional view of the portion of the fixation belt, which is shown in FIG. 17( b ), when the portion is in the fixation nip, having thereby been made to be concave in circular curvature, that is, deformed in such a manner that its is reversed in curvature from when it is in the state shown in FIG. 17( a ). Also in FIG. 17( c ), referential codes Le′ and Li′ stand for the length of the outward surface of the portion outlined by the solid line, and the length of the inward surface of the portion outlined by the solid line, respectively. The length Le′ has no direct relation to the wrinkling of the portion. It is the direct distance between points A and B in FIG. 17( c ) that has direct relation to the wrinkling.
First, a case in which a given portion of the fixation belt is flattened in the fixation nip as shown in FIG. 17( b ) is described. As a portion of the fixation belt, the curvature of which is as shown in FIG. 17( a ) is flattened as shown in FIG. 17( b ), the inward surface of the fixation belt is slightly stretched, whereas the outward surface of the fixation belt is compressed by such an amount that makes its length roughly the same as the length of the stretched inward surface of the fixation belt. Generally speaking, a fixation belt is provided with a parting layer, which makes up the actual outward surface layer of the fixation belt, as will be described later. The parting layer cannot be easily compressed. Thus, as it is subjected to compressive force, it fails to be compressed. Consequently, it is wrinkled.
Here, the amount of difference between the pre-deformation length of the outward surface layer of the fixation belt and the post-deformation length of the outward surface layer of the fixation belt is referred to as the amount of fixation belt compression or fixation belt compression amount. The amount of fixation belt compression is expressible in the form of the following Equation (1).
Amount of compression= Le−Le′ (1)
In a case where a given portion of the fixation belt is flattened in the fixation nip, the length Le′, that is, the length of the outward surface of the given portion after the deformation of the portion, is the same as the length Le′, that is, the length of the inward surface of the given portion after the deformation. The dimension of the fixation nip in terms of the circumferential direction of the fixation belt, is very small relative to the circumference of the fixation belt. Thus, the angle θ is very small relative to 360° which corresponds to the circumference of the fixation belt. Therefore, it is reasonable to say that the length Li, which is the pre-deformation length of the inward surface of the given portion of the fixation belt is roughly the same as the length Li,′ that is, the post-deformation length of the inward surface of the given portion of the fixation belt. Thus, Equation (1) which shows the amount of fixation belt compression may be rewritten as follows:
Amount of Compression= Le−Le′=Le−Li′≈Le−Li (2)
Further, the length Le, or the pre-deformation length of the outward surface layer of the fixation belt, can be obtained from the radius Re of the outward surface layer of the fixation belt and the angle θ of the sector of the cross-section of the fixation belt: Le=θ×Re. Similarly, the length Li, or the pre-deformation length of the inward surface of the given portion of the fixation belt, can be obtained from the radius Ri and the angle θ: Li=θ×Ri. Thus, Equation (2) can be rewritten as follows:
Amount
of
Compression
∝
θ
×
Re
-
θ
×
Ri
=
θ
×
(
Re
-
Ri
)
=
θ
W
.
(
3
)
A letter W stands for the thickness of the fixation belt as described above. As is evident from Equation (3), the amount of the compression of the fixation belt is proportional to the thickness W of the fixation belt. The greater the amount of the fixation belt compression, the greater the extent of the wrinkling of the outward surface layer of the fixation belt. Therefore, in a case where a given portion of the fixation belt is flattened in the fixation nip, the thicker the fixation belt, (as fixation belt is increased in thickness W), the greater the extent of the wrinkling of the outward surface layer of the fixation belt (surface layer of fixation belt wrinkles more), and therefore, the greater the extent of the image defect called “cracking”.
Next, referring to FIG. 17( c ), a case in which a given portion of the fixation belt is bent in the fixation nip in such a shape that it is made to concave toward the rotational axis of the fixation belt, that is, it is reversed in curvature from when it is in the state shown in FIG. 17( a ), is described. As the given portion, the curvature of which was as shown in FIG. 17( a ), is bent so that its curvature becomes as shown in FIG. 17( c ), the inward surface of the fixation belt is stretched, but, the outward surface layer of the fixation belt is compressed. Thus, the outward surface layer of the fixation belt is made to wrinkle for the same reason as the one given above.
Also in this case, the “amount of compression” which is the difference between the pre-deformation length of the surface layer of a given portion of the fixation belt and the post-deformation length of the surface layer of the given portion of the fixation belt can be defined as in the case where the given portion is deformed as shown in FIG. 17( b ). Referring to FIG. 17( c ), the given portion of the fixation belt is deformed in such a shape that its curvature equals a circle, the radius of which is Rc, and the length of which is equivalent to the angle θ′ of this circle, the “amount of compression” can be expressed in the form of the following Equation.
Amount
of
Compression
=
Le
-
Le
′
=
θ
×
Re
-
θ
′
×
(
Rc
-
W
)
=
θ
′
Re
-
θ
′
Rc
+
θ
′
W
.
(
4
)
Based on Equation (4), even in a case where a given portion of the fixation belt is deformed in such a manner that it is made to concave, the thicker the fixation belt, the greater the amount of compression of the given portion, and therefore, the greater the extent of the wrinkling of the outward surface layer of the fixation belt. From Equation (4), the smaller the given portion in the post-deformation radius Rc (greater in curvature), the greater the amount of compression, and therefore, the greater it will be in the extent of wrinkling. Therefore, the greater it will be in the extent of the image defect which is referred to as “cracking”.
As will be evident from the foregoing, as a given portion of the fixation belt, the curvature of which is as shown in FIG. 17( a ), is flattened or reversed in curvature as shown in FIGS. 17( b ) and 17 ( c ), respectively, the surface layer of this portion of the fixation belt is compressed, being therefore reduced in length. Therefore, it becomes positive in the amount of compression, which is calculable with the use of Equation (1). In comparison, in a case where the given portion of the fixation belt is stretched as it is deformed, it becomes positive in the amount of compression which is obtainable with the use of Equation (1), although this case is not illustrated here.
In other words, in a case where the amount of compression is positive, the fixation belt wrinkles, and the greater the amount of compression, the greater the extent of wrinkling. The greater the extent of wrinkling, the more serious, the image defect attributable to the wrinkling of the fixation belt. On the other hand, in a case where the amount of compression is negative, the fixation belt does not wrinkle. Therefore, the image defect attributable to the wrinkling of the fixation belt hardly occurs.
As will be evident from the foregoing description, the thicker the fixation belt, the greater it is in the difference between its internal (substrative layer) external diameters (surface layer), and therefore, the greater it is in the extent of wrinkling, or the vertical distance between the highest point of its peak and the bottom of its valley.
In recent years, a copying machine, a printer, and the like devices have come to be desired to be substantially increased in speed. Thus, in order to ensure that they remain satisfactory in image quality (fixation, in particular) in spite of increase in speed, they have been substantially increased in the thickness of the elastic layer of their fixation belt, as will be described later. Consequently, they have become substantially larger in the difference between the internal and external diameters of their fixation belt. Thus, it is reasonable to think that the issues related to the image defect, which is referred to as “cracking”, will become one of the greater concerns. Further, it is also to be ensured that a sheet of recording medium easily separates from a fixation belt.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a fixing apparatus with which image defects attributable to the crease of the belt surface layer can be suppressed, and a separation of the recording material is easy.
According to an aspect of the present invention, there is provided a fixing apparatus comprising a cylindrical belt; a back-up member contacting an inner surface of said belt; a roller contacting an outer surface of said belt, said roller being provided with an elastic layer, said roller being cooperative with said back-up member to sandwich said belt and form a fixing nip between said belt and said roller; wherein a recording material carrying an unfixed toner image is nipped and fed through the fixing nip, during which the unfixed toner image on the recording material is heated and fixed thereon by the fixing nip, and wherein said back-up member includes a portion contactable with the inner surface of said belt, the portion having such a configuration that said belt forms a first curved surface which is substantially convex toward said roller in an upstream region in said fixing nip with respect to a moving direction of said belt and that said belt forms a second curved surface which is substantially convex toward said back-up member in a downstream region in said fixing nip with respect to the moving direction.
Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic sectional view of a typical image forming apparatus to which the present invention is applicable, and shows the general structure of the apparatus.
FIG. 2 is a schematic cross-sectional view of the fixing device in the first embodiment of the present invention, and shows the general structure of the device.
FIG. 3( a ) is a schematic side view of the fixing device in the first embodiment, as seen from the upstream side of the device in terms of the recording conveyance direction, and shows the general structure of the device, and FIG. 3( b ) is a schematic vertical sectional view of the fixing device shown in FIG. 3( a ), and shows the general structure of the device.
FIG. 4 is a schematic sectional view of the fixation belt of the fixing device in the first embodiment, and shows the laminar structure of the belt.
FIG. 5 is a schematic cross-sectional view of the fixation nip, and its adjacencies, of the fixing device in the first embodiment, and shows the general structure of the fixation nip and its adjacencies.
FIG. 6 is a schematic drawing for showing the amount of compression of the outward surface layer of the fixation belt of the fixing device in the first embodiment, in the fixation nip.
FIG. 7 is a magnified view of a part of a toner image fixed to a sheet of recording medium by the fixing device in the first embodiment, which was obtained with the use of a microscope.
FIG. 8 is a schematic cross-sectional view of the fixing device in the second embodiment of the present invention, and shows the general structure of the device.
In FIG. 9 , ( a ) is a schematic side view of the fixing device in the second embodiment, as seen from the upstream side of the device in terms of the recording conveyance direction, and shows the general structure of the device, and ( b ) is a schematic vertical sectional view of the fixing device shown in FIG. 9( a ), and shows the general structure of the device.
FIG. 10 is a rear view of the ceramic heater of the fixing device in the second embodiment, and shows the general structure of the ceramic heater.
FIG. 11 is a schematic cross-sectional view of the fixation nip, and its adjacencies, of the fixing device in the second embodiment, and shows the general structure of the fixation nip and its adjacencies.
FIG. 12 is a schematic drawing for showing the amount of compression of the outward surface layer of the fixation belt of the fixing device in the second embodiment, in the fixation nip.
FIG. 13 is a schematic sectional view of the fixation nip, and its adjacencies, of the fixing device in the third embodiment, and shows the general structure of the fixation nip and its adjacencies.
FIG. 14 is a schematic drawing for showing the amount of compression of the outward surface layer of the fixation belt of the fixing device in the third embodiment, in the fixation nip.
FIG. 15 is a schematic cross-sectional view of the fixation nip, and its adjacencies, of the fixing device in the fourth embodiment, and shows the general structure of the fixation nip and its adjacencies.
FIG. 16 is a magnified view of a part of a toner image fixed to a sheet of recording medium by a conventional fixing device, which was obtained with the use of a microscope.
FIG. 17 is a schematic drawing for explaining the principle, based on which the surface layer of a fixation belt wrinkles.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, the present invention is described in detail with reference to the appended drawings.
[Embodiment 1]
(1) Example of Image Forming Apparatus
FIG. 1 is a schematic sectional view of a typical image forming apparatus which employs a fixing device which is in accordance with the present invention. It shows the general structure of the apparatus. This image forming apparatus is a full-color laser beam printer which uses an electrophotographic image forming method. It is structured so that a sheet of recording medium is conveyed through the apparatus in such a manner that, in terms of the direction perpendicular to the recording medium conveyance direction of the apparatus, the center of the sheet of recording medium coincides with the center CL ( FIG. 3( a )) of the recording medium passage of the apparatus.
The image forming apparatus in this embodiment has: an image formation section A which forms an unfixed toner image (image) on a sheet P of recording medium; a fixation section B which fixes the unfixed toner image on the sheet P of recording medium, to the sheet P; a control section C which controls the entirety of the apparatus; etc. The image formation section A has: four image formation stations Pa, Pb, Pc and Pd, which form cyan, magenta, yellow, and black monochromatic images, respectively; an intermediary transfer belt 7 ; etc. The control section C is made up of a CPU, and memories such as a ROM and a RAM. The memories store image formation sequences, various tables necessary for image formation, etc.
The image formation stations Pa, Pb, Pc and Pd have developing devices (developing means) 1 a , 1 b , 1 c and 1 d , which have toner containers 1 a 1 , 1 b 1 , 1 c 1 and 1 d 1 and development rollers 1 a 2 , 1 b 2 , 1 c 2 and 1 d 2 , etc., which contain cyan, magenta, yellow, and black toners, respectively.
The image forming operation of the image forming apparatus in this embodiment is as follows. As the control section C receives a print command from an external apparatus (unshown) such as a host computer, it carries out an image formation control sequence. As the image formation sequence is started, the electrophotographic photosensitive members 3 a , 3 b , 3 c and 3 d (which are in the form of a drum, and therefore, will be referred to simply as photosensitive drum, hereafter), in the image formation stations Pa, Pb, Pc and Pd, respectively, are rotated in the direction indicated by arrow marks at a preset peripheral velocity (process speed). Further, the intermediary transfer belt 7 , which is below the combination of the image formation stations Pa, Pb, Pc and Pd, and is stretched around the combination of three rollers, more specifically, a driver roller 8 , a belt backing roller 9 which opposes a secondary transfer roller, and a tension roller 10 , is rotated in the direction indicated by an arrow mark at a peripheral velocity which is equal to the peripheral velocity of the photosensitive drums 3 a , 3 b , 3 c and 3 d.
In the image formation station Pa, the peripheral surface of the photosensitive drum 3 a is uniformly charged by a charge roller (charging means) 2 a to preset polarity and potential level (charging process). Then, the uniformly charged portion of the peripheral surface of the photosensitive drum 3 a is scanned by (exposed to) a beam of laser light outputted by a laser-based exposing device (exposing means) 5 , whereby an electrostatic latent image, which is in accordance with the information of the image to be formed, is formed on the peripheral surface of the photosensitive drum 3 a (exposing process). This latent image is developed into a visible image through a process of adhering toner of cyan color, which is in the toner container 1 a 1 of the developing device (developing means) 1 a , to the latent image by the development roller 1 a 2 . Consequently, a toner image of cyan color is formed on the peripheral surface of the photosensitive drum 3 a (developing process).
Also in the image formation stations 1 b , 1 c and 1 d , the charging, exposing, and developing processes which are similar to the above described ones carried out in the image formation station 1 a , are carried out. Consequently, a toner image of magenta color, a toner image of yellow color, and a toner image of black color, are formed on the peripheral surface of the photosensitive drum 3 b , peripheral surface of the photosensitive drum 3 c , and peripheral surface of the photosensitive drum 3 d in the image formation stations 1 b , 1 c and 1 d , respectively.
The toner image of cyan color on the peripheral surface of the photosensitive drum 3 a is conveyed, by the rotation of the photosensitive drum 3 a , to the first transfer nip formed by the peripheral surface of the photosensitive drum 3 a and the outward surface of the intermediary transfer belt 7 , and then, is conveyed through the first transfer nip. While it is conveyed through the first transfer nip, a preset transfer bias is applied to a primary transfer roller 6 a , which is positioned so that it opposes the photosensitive drum 3 a , with the presence of the intermediary transfer belt 7 between itself and photosensitive drum 3 a . Consequently, the toner image of cyan color on the peripheral surface of the photosensitive drum 3 a is transferred onto the surface of the intermediary transfer belt 7 (primary transferring process).
Primary transferring processes (image formation processes) similar to the above described one are carried out in the image formation stations 1 b , 1 c , and 1 d , one for one. That is, as a preset transfer bias is applied to the primary transfer roller 6 b , the toner image of magenta color is transferred onto the intermediary transfer belt 7 in such a manner that it is layered upon the toner image of cyan color on the intermediary transfer belt 7 . Further, a preset transfer bias is applied to the primary transfer roller 6 c , the toner image of yellow color is transferred onto the intermediary transfer belt 7 in such a manner that it is layered upon the toner image of magenta color on the intermediary transfer belt 7 . Moreover, as a preset transfer bias is applied to the primary transfer roller 6 d , the toner image of black color is transferred onto the intermediary transfer belt 7 in such a manner that it is layered upon the toner image of yellow color on the intermediary transfer belt 7 . Consequently, an unfixed full-color is formed of four monochromatic images, different in color, on the surface of the intermediary transfer belt 7 .
Then, the unfixed full-color toner image on the intermediary transfer belt 7 is conveyed by the rotation of the intermediary transfer belt 7 to the secondary transfer nip formed by the surface of the intermediary transfer belt 7 , and the peripheral surface of the secondary transfer roller 11 . The secondary transfer roller 11 is positioned so that it sandwiches the intermediary transfer belt 7 between itself and the belt backing roller 8 .
The transfer residual toner, that is, the toner remaining on the peripheral surface of the photosensitive drums 3 a , 3 b , 3 c and 3 d after the secondary transfer of the toner images, is removed by cleaning blades (cleaning means) 4 a , 4 b , 4 c and 4 d , which correspond in position to the photosensitive drums 3 a , 3 b , 3 c and 3 d , so that the photosensitive drums 3 a , 3 b , 3 c and 3 d can be used for the following image formation. After the removal of the transfer residual toner by the cleaning blades 4 a , 4 b , 4 c and 4 d , the transfer residual toner is stored in waste toner containers 4 a 1 , 4 b 1 , 4 c 1 and 4 d 1 , respectively.
Meanwhile, sheets P of recording medium in a sheet feeder cassette 14 are fed one by one into the main assembly of the image forming apparatus. Then, each sheet P of recording medium is conveyed by a pair of sheet conveyance rollers 16 to a pair of registration rollers 17 , which conveys the sheet P to the secondary transfer nip with a preset timing. Then, the sheet P is conveyed through the secondary transfer nip while remaining pinched by the surface of the intermediary transfer belt 7 and the peripheral surface of the secondary transfer roller 11 . While the sheet P is conveyed through the secondary transfer nip, the unfixed full-color toner image on the surface of the intermediary transfer belt 7 is transferred onto the sheet P by a preset transfer bias applied to the secondary transfer roller 11 (secondary transfer process). Consequently, the unfixed full-color toner image made up of the four monochromatic toner images, different in color, is borne by the sheet P of recording medium.
After the transfer of the unfixed full-color toner image from the intermediary transfer belt 7 , the surface of the intermediary transfer belt 7 is rid of the transfer residual toner, by the cleaning web (unwoven cloth) 12 a , to be readied for the next image formation. The removed transfer residual toner is stored in a waste toner container 12 a 1 .
The sheet P of recording medium, on which the unfixed full-color toner image is present is introduced into, and conveyed through, the fixation nip N (which will be described later) of the fixing section (which hereafter will be referred to as fixing device) B. While the sheet P is conveyed through the fixation nip N, the unfixed toner image is thermally fixed to the sheet P. Then, the sheet P is moved out of the fixation nip N, is conveyed to the delivery tray 19 , and then, is discharged into the delivery tray 19 .
There is present between the fixing device B and delivery tray 19 , a recording medium turning mechanism 18 , which turns the sheet P over so that the image bearing surface of the sheet P is switched in position with the surface of the sheet P which has no image.
(2) Fixing Apparatus (Fixing Device) B
(2-1) General Structure of Fixing Apparatus B
FIG. 2 is a schematic cross-sectional view of the fixing device B in this embodiment. FIG. 3( a ) is a schematic side view of the fixing device B in this embodiment as seen from the upstream side of the device in terms of the recording medium conveyance direction of the device B. It shows the general structure of the device B. FIG. 3( b ) is a schematic vertical sectional view of the fixing device B, shown in FIG. 3( a ). It shows the general structure of the fixing device B. This fixing device B employs a fixation belt which is heated by electromagnetic induction.
The fixing device B in this embodiment has a fixation belt (heating belt) 100 , a belt guide (heating belt guide) 101 , and a pressure roller (pressure applying member) 104 . It has also a belt backing member 108 , a friction reducing sheet 109 which guides the fixation belt 100 , a coil unit 110 , etc. The fixation belt 1001 , belt guide 101 , pressure roller 104 , and belt backing member 108 , friction reducing sheet 109 , and coil unit 110 are long and narrow, and their lengthwise direction is perpendicular to the sheet of paper on which FIG. 2 is present.
The fixation belt 100 is flexible and cylindrical. It is loosely fitted around a combination of the belt guide 101 and belt backing member 108 . The belt guide 101 is formed of heat resistant resin, such as LCP (Liquid Crystal Polymer). It is roughly in the form of a trough, and is positioned so that its open side faces toward the rotational axis of the fixation belt 100 . The belt backing member 108 is attached to the bottom surface of the belt guide 101 . The fixation belt 100 in this embodiment is 30 mm in external diameter, and its dimension in terms of the direction parallel to the lengthwise direction of the fixing device 100 , is greater than the length of a largest sheet of recording medium, which can be conveyed through the fixing device B ( FIG. 3( a )).
Referring to FIGS. 3( a ) and 3 ( b ), the fixing device B is provided with a flange 102 a , which is at one of the lengthwise ends of the fixation belt 100 (left side of FIGS. 3( a ) and 3 ( b )). The flange 102 a has a base portion 102 a 1 , the external diameter of which is greater than the external diameter of the fixation belt 100 . The base portion 101 a 1 has: a belt guide 102 a 2 , which protrudes inward of the fixation belt loop (loop which fixation belt 100 forms); and a pressure bearing portion 102 a 3 which protrudes from the base portion 101 a 1 , in the opposite direction from the belt guide 102 a 2 . The belt guide 102 a 2 is roughly semi-cylindrical, and its radius is less than the internal radius of the fixation belt 100 . It guides the fixation belt 100 to prevent the fixation belt 100 from deviating in the lengthwise direction of the fixing device B, as the belt 100 is rotated.
Further, the fixing device B is provided with a flange 102 b , which is at the other lengthwise end (right side of FIGS. 3( a ) and 3 ( b )) of the fixation belt 100 from where the flange 102 a is present. The flange 102 b has a base portion 102 b 1 , the external diameter of which is greater than the external diameter of the fixation belt 100 . The base portion 102 b 1 has: a belt guide 102 b 2 , which protrudes inward of the fixation belt loop; and a pressure bearing portion 102 b 3 which protrudes from the base portion 102 b 1 , in the opposite direction from the belt guide 102 b 2 . The belt guide 102 b 2 is roughly semi-cylindrical, and its radius is less than the internal radius of the fixation belt 100 . It guides the fixation belt 100 to prevent the fixation belt 100 from deviating in the lengthwise direction of the fixing device B, as the belt 100 is rotated.
The base portions 102 a 1 and 102 b 1 are provided with recesses 102 a 4 and 102 b 4 ( FIG. 2( b )), which face the pressure roller 104 and extend in the lengthwise direction of the fixation belt 100 . The belt guide 101 and belt backing member are fitted in these recesses 102 a 4 and 102 b 4 , being thereby supported by their lengthwise ends, by the base portions 102 a 1 and 102 b 1 .
The base portions 102 a 1 and 102 b 1 of the flanges 102 a and 102 b , which are positioned at the lengthwise ends of the fixation belt 100 , one for one, are supported by the lateral plates Fa and Fb of the frame (unshown) of the fixing device B, respectively, in such a manner that they can be vertically moved.
The pressure roller 104 has: a metallic core 105 ; a rubber layer (elastic layer) 106 , which covers the entirety of the peripheral surface of the metallic core 105 , except for the lengthwise end portions 105 a and 105 b of the metallic core 105 ; a parting layer 107 which covers the peripheral surface of the rubber layer 106 ; etc. In this embodiment, the material for the metallic core is SUS (steel use stainless). The material for the rubber layer 106 is silicone rubber or the like. The parting layer 107 is formed of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA). The diameter of the pressure roller 104 in this embodiment is 24 mm.
In terms of the direction parallel to the recording medium conveyance direction, the above described pressure roller 104 is disposed so that a vertical line Vr which coincides with the rotational axis of the pressure roller 104 and is perpendicular to the generatrix of the pressure roller 104 , is on the upstream side of the vertical line Vb which coincides with the rotational axis of the fixation belt 100 and is perpendicular to the generatrix of the fixation belt 100 , being separated by a preset width Wa ( FIG. 2 ). This pressure roller 104 , and the belt backing member 108 which is on the inward side of the fixation belt loop, sandwich the fixation belt 100 . The pressure roller 104 is rotatably supported by the lateral plates Fa and Fb, by the lengthwise end portions (shaft portions) 105 a and 105 b , with the placement of a pair of bearings (unshown) between the lengthwise end portions 105 a and 105 b and lateral plates Fa and Fb, respectively.
The belt backing member 108 , which is not rotational, is a member for pressing the fixation belt 100 upon the pressure roller 104 to form the fixation nip N. The belt backing member 108 has a fixation belt pressing surface 108 a , which is its downwardly facing surface and faces the pressure roller 104 . The fixation belt pressing surface 108 a is pressed on the inward surface of the fixation belt 100 , forming thereby the fixation nip N. The shape of the fixation belt pressing surface 108 a will be described later in detail. In this embodiment, the material for the belt backing member 108 is heat resistant resin such as LCP (liquid Crystal Polymer). It may be a ceramic or metallic substance.
Each of the pressure bearing portions 102 a 3 and 102 b 3 of the above described flanges 102 a and 102 b is under 300 N of pressure generated by each of a pair of coil springs 116 a and 116 b , in the directions indicated by arrow marks Pa and Pb, which are perpendicular to the pressure application referential surfaces 117 a and 117 b . Thus, the flanges 102 a and 102 b are kept pressed toward the pressure roller 104 by the resiliency of the coil springs 116 a and 116 b , causing the fixation belt pressing surface 108 a of the belt backing member 103 to press on the inward surface of the fixation belt 100 . Thus, the outward surface of the fixation belt 100 is pressed upon the peripheral surface of the pressure roller 104 .
As the outward surface of the fixation belt 100 is pressed upon the peripheral surface of the pressure roller 104 , the rubber layer 106 of the pressure roller 104 is compressed, being thereby elastically deformed. Consequently, the fixation nip N, which has a preset dimension (width) in terms of the rotational direction of the fixation belt 7 , is formed between the outward surface of the fixation belt 100 and the peripheral surface of the pressure roller 104 . In this embodiment, the width (in terms of rotational direction of fixation belt 100 ) of the fixation nip N is 8.4 mm.
The fixing device B in this embodiment is provided with the friction reducing sheet 109 , which is placed between the fixation belt 100 and the belt backing member 108 to minimize the friction between the inward surface of the fixation belt 100 and the fixation belt pressing surface 108 a of the belt backing member 108 , in order to enable the fixation belt 100 to smoothly slide on the fixation belt pressing surface 108 a of the belt backing member 108 . This friction reducing sheet 109 is large enough to cover the entirety of the fixation belt pressing surface 108 a in terms of the widthwise direction of the belt backing member 108 . It is attached to the belt backing member 108 with the use of adhesive or the like to cover the entirety of the fixation belt pressing surface 108 a . The material for the friction reducing sheet 109 is polyimide.
Next, referring to FIG. 4 , the laminar structure of the fixation belt 100 is described. The fixation belt 100 has: a hollow, cylindrical, and metallic substrative layer, which generates heat by electromagnetic induction; an elastic layer 113 formed on the peripheral surface of the sustrative layer 112 , with the placement of a primary layer (unshown) between the peripheral surface of the substrative layer and the elastic layer 113 p ; and a parting layer 114 formed of fluorinated resin, on the outward surface of the elastic layer 113 .
As the material for the substrative layer 112 , nonmagnetic stainless steel, aluminum, or the like, may be used in place of magnetic metal such as iron, nickel, and stainless steel. In this embodiment, nickel is used as the material for the substrative layer 112 . Regarding the thickness of the substrative layer 112 , from the standpoint of temperature control and thermal response, it is desired to be as small as possible in thermal capacity, and therefore, as thin and possible. However, from the standpoint of durability, it is desired as thick as possible. Thus, the thickness of the substrative layer 112 in this embodiment was made to be roughly one to several hundred times the depth of penetration of electromagnetic wave, the frequency of which is in a range of 20 kHz-several hundreds kHz, that is, the range suitable for electromagnetic induction. In this embodiment, the thickness of the substrative layer 112 was 75 μm.
As the material for the elastic layer 113 , a substance such as silicone rubber, fluorinated rubber, and fluoro-silicone rubber, that is excellent in heat resistance and thermal conductivity is used. In this embodiment, solid silicone rubber which is 0.50-1.60 W/m·K in thermal conductivity was used. The elastic layer 113 in this embodiment was 280 μm in thickness.
As the material for the parting layer 114 in this embodiment, PFA was used. However, instead of PFA, fluorinated resin such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), or the like, may be used as the material for the parting layer 114 . Further, the parting layer 114 may be a layer of GLS latex paint coated on the outward surface of the elastic layer 113 . That is, the parting layer 114 may be a piece of tube stretched to cover the entirety of the outward surface of the elastic layer 113 , or a layer of the abovementioned paint coated on the outward surface of the elastic layer 113 . A piece of tube, which is excellent in durability was used. The thickness of the parting layer 114 was 30 μm.
In order to minimize the friction between the fixation belt 100 and friction reducing sheet 109 , the inward surface of the fixation belt 100 is coated with a slippery substance. In this embodiment, the material of this friction reducing layer on the inward surface of the fixation belt 100 was polyimide, and the thickness of this layer was 30 μm.
A coil unit 110 is disposed on the opposite side of the fixation belt 100 from the pressure roller 104 . It has: an excitation coil 111 (magnetic field generating means) as a heating energy source; a magnetic core 112 ; a holder 113 ; etc.
The holder 113 is in the form of a long and narrow box, the lengthwise direction of which is parallel to the lengthwise direction of the fixation belt 100 . It is disposed in parallel to the fixation belt 100 , with its lengthwise end portions held by the aforementioned lateral plates Fa and Fb, one for one ( FIG. 3( a )). More concretely, the holder 113 is in the form of a shallow trough, which is semi-circular in cross-section, and the curvature of which matches the curvature of the outward surface of the fixation belt 100 . It is disposed so that its concave side opposes the outward surface of the fixation belt 100 with the presence of a preset gap g between itself and fixation belt 100 .
The excitation coil 111 is shaped so that its curvature matches the curvature of the fixation belt 100 . It is in the holder 113 , being positioned so that a preset distance is maintained between itself and the outward surface of the fixation belt 100 . As the wire for the excitation coil 111 , litz wire made by bundling several tens to roughly 200 strands of electrically conductive fine wire, which are 0.1-0.3 mm in diameter, was used. The fine wire is coated with electrically insulating substance. That is, the excitation coil 111 was made by winding the litz wire around the magnetic core 112 several to several tens of times. The excitation coil 111 is in connection to an excitation circuit 200 so that alternating electric current can be supplied to the excitation coil 111 from the excitation circuit 200 .
The magnetic core 112 is made of a ferromagnetic substance. It is structured so that it embraces the excitation coil, with its center portion fitting in the center of the excitation coil 111 . The magnetic core 111 plays the role of efficiently guiding the alternating magnetic flux generated by the excitation coil 111 , to the substrative layer 112 of the fixation belt 100 . That is, the magnetic core 112 improves in efficiency the magnetic circuit made up of the excitation coil 111 and the substrative layer 112 of the fixation belt 100 .
The length of the excitation coil 111 , and the length of the magnetic core 112 , are greater than the length of the long edge of a largest sheet of paper conveyable through the fixing device B.
(2-2) Driving and Temperature Control of Fixing Device B
The control section C rotationally drives a motor ( FIG. 2 ) M as a driving force source, in response to a print command. The rotation of the output shaft of the motor M is transmitted to a driving gear (unshown) attached to one of the lengthwise ends of the metallic core 105 , through a gear train (unshown). Thus, the pressure roller 104 rotates at a preset peripheral velocity in the direction indicated by an arrow mark. In this embodiment, the pressure roller 104 is rotated at a peripheral velocity of 321 mm/sec.
The rotation of this pressure roller 104 is transferred, as belt driving force, to the fixation belt 100 by the friction between the peripheral surface of the pressure roller 104 and the outward surface of the fixation belt 100 , in the fixation nip N. Thus, the fixation belt 100 is rotated by the rotation of the pressure roller 104 , remaining in contact with the friction reducing sheet 109 by its inward surface. It is possible that while the fixation belt 100 is rotated, it will deviate in its lengthwise direction. However, if the fixation belt 100 deviates in its lengthwise direction, one of its edges comes into contact with the base portion 102 a or 102 b of the corresponding flange 102 a or 102 b , respectively. Therefore, the fixation belt 100 is prevented from deviating in its lengthwise direction.
Further, the control section C starts up the excitation circuit 200 in response to the print command. The excitation circuit 200 causes alternating electric current to flow through the excitation coil 111 of the coil unit 110 . Thus, the excitation coil 111 generates an alternating magnetic flux. This alternating magnetic flux is guided by the magnetic core 112 to the fixation belt 100 , generating thereby eddy current in the outward surface layer of the fixation belt 100 . Thus, Joule's heat is generated in the fixation belt 100 due to the presence of the intrinsic electrical resistance of the substrative layer 112 .
The temperature of the fixation belt 100 is detected by a temperature detecting member S, such as a thermistor, which is placed in the adjacencies of, or in contact with, the outward surface of the fixation belt 100 . Then, the signals outputted by the temperature detecting member S are taken in by the control section C. Then, the control section C controls the excitation circuit 200 in response to the output signals from the temperature detecting member S, so that the temperature of the fixation belt 100 remains at a preset level (fixation temperature: target temperature).
While the motor M is rotationally driven, and the alternating electric current is flowed through the excitation coil 111 , a sheet P of recording medium, on which an unfixed toner image is present, is introduced into the fixation nip N, in such an attitude that the image bearing surface of the sheet P faces the fixation belt 100 . Then, the sheet P is conveyed through the fixation nip N, remaining sandwiched between the outward surface of the fixation belt 100 and the peripheral surface of the pressure roller 104 . While the sheet P is conveyed through the fixation nip N, the unfixed toner image on the sheet P is heated by the heat of the fixation belt 100 , while being subjected to the internal pressure of the fixation nip N. Thus, the unfixed toner image on the sheet P becomes fixed to the sheet P. Then the sheet P is conveyed out of the fixation nip N. Then, the sheet P is discharged from the fixing device B in such a manner that the toner image bearing surface of the sheet P separates from the outward surface of the fixation belt 100 .
(3) Shape of Fixation Belt Pressing Surface 108 a of Belt Backing Member 108
FIG. 5 is a schematic cross-sectional view of the fixation nip N, and its adjacencies, of the fixing device B in this embodiment. It shows the structure of the fixation nip N and its adjacencies. It should be noted here that in order to make it easier to recognize the shape of the fixation belt pressing surface 108 a of the belt backing member 108 , the belt guide 101 and friction reducing sheet 109 are not illustrated in FIG. 5 .
In this embodiment, the shape of the fixation belt pressing surface 108 a of the belt backing member 108 , in terms of its cross-sectional view, is such that the portion of the fixation belt pressing surface 108 a , which is in the upstream area of the fixation nip N, in terms of the recording medium conveyance direction, bulge in circular curvature (first curved surface) toward the pressure roller 104 , whereas the portion of the fixation belt pressing surface 108 a , which is the downstream area of the fixation nip N concaves in curvature (second curved surface).
More concretely, referring to FIG. 5 , in this embodiment, the portion of the fixation belt pressing surface 108 a , which bulges in circular curvature, was 7 mm in width, and the portion of the fixation belt pressing surface 108 a , which concaves in curvature was 3.3 mm in width. Further, the portion of the fixation belt pressing surface 108 a , which bulges in circular curvature toward the pressure roller 104 in the upstream area of the fixation nip N was 6.1 mm in width. Therefore, the rest of the fixation belt pressing surface 108 a , which is in the fixation nip N and concaves in curvature, was 2.3 mm (8.4 mm (nip width)-upstream portion (6.1 mm)) in width. Here, “bulges in circular curvature” means to protrude in curvature toward the pressure roller 104 , and “concaves in curvature” means to recess toward the opposite surface of the belt backing member 108 from the fixation belt pressing surface 108 a.
That is, in terms of the cross-sectional view of the belt backing member, the portion of the fixation belt pressing surface 108 a of the belt backing member 108 , which is in the upstream area Nu of the fixation nip N relative to the center Nc of the fixation nip N in terms of the recording medium conveyance direction, bulges in circular curvature toward the pressure roller 104 , whereas the portion of the fixation belt pressing surface 108 a of the belt backing member 108 , which is in the area between the downstream edge Nut of the upstream area Nu, and the downstream edge of the fixation nip N, in terms of the rotational direction of the fixation belt 100 , concaves in curvature away from the pressure roller 104 .
In the case of the fixing device B in this embodiment, the above described curvature in which the upstream portion of the fixation belt pressing surface 108 a bulges toward the pressure roller is equivalent to the curvature of a circle which is 15 mm in radius (which hereafter may be referred to as R 15 ). As described above, the external diameter of the fixation belt 100 is 30 mm (R 15 ). Thus, the relationship between the radius R 1 of the curvature in which the upstream portion of the fixation belt pressing surface 108 a bulges, and the radius R 2 is: R 1 =R 2 . Therefore, when a given portion of the fixation belt 100 , is in the portion of the fixation nip N, which is between the entrance Nin of the fixation nip N to a point which is 6.1 mm downstream from the entrance Nin, the given portion of the fixation belt 100 is allowed to maintain its intrinsic curvature, and therefore, it smoothly moves, that is, without being stressed. Thus, in the above described area of the fixation nip N, that is, the area from the nip entrance Nin to the point which is 6.1 mm downstream from the entrance Nin, the above described amount of “compression” of the outward surface layer of the fixation belt 100 is zero.
In comparison, the curvature of the above-described concaved portion is equivalent to the curvature of a circle which is R 17 . 5 . Therefore, the amount of compression of the portion of the fixation belt 100 , which is between the downstream edge Nut of the upstream portion area Nu in the fixation nip N, and the exit Nout of the fixation nip N, is greater than zero (amount of compression >0).
FIG. 6 shows the changes in the amount of compression of the outward surface layer of the fixation belt 100 , which occur in the fixation nip N. As will be evident from FIG. 6 , in the case of the fixing device B in this embodiment, which is structured as described above, the amount by which fixation belt 100 is compressed in the upstream area Nu of the fixation nip, relative to the center Nc of the fixation nip N, is no more than zero (amount of compression ≦0. Therefore, it is unlikely that this area of the fixation nip N causes image defects. The temperature of the toner, of which the unfixed toner is formed (toner on sheet P), exceeds the softening point (Tg) of toner while the toner is in the upstream area Nu in the fixation nip N relative to the center Nc, although it will be affected by the condition under which an image forming apparatus is used. Therefore, if the parting layer 114 , which is the outward surface layer of the fixation belt 100 wrinkles in the upstream area Nu of the fixation nip N, it is likely for some of the toner particles on a sheet P of recording medium to be shifted in position. Therefore, it is desired that the portion of the fixation belt pressing surface 108 a of the belt backing member 108 , which bulges in circular curvature toward the pressure roller 104 , extends downstream from the nip entrance Nin beyond the center Nc of the fixation nip N.
The amount by which the fixation belt 100 is compressed in the downstream area Nd of the fixation nip N, which is 2.3 mm in width is positive in value. However, in the downstream area Nd in the fixation nip N, the toner particles on the sheet P of recording medium will have melted further, becoming therefore better fixed to the sheet P, as described before. Therefore, even if the parting layer 114 , that is, the outward surface layer of the fixation belt 100 , wrinkles, it hardly occurs that the toner particles on the sheet P are shifted in position enough for the area of the surface of the sheet P, which is under the toner particles, to become exposed.
Shaping the fixation belt backing member 108 so that its portion in the upstream area Nu of the fixation nip N bulges in circular curvature toward the pressure roller 104 , has the secondary effect, which is the increase in the internal pressure of the upstream area Nu in the fixation nip N. Making the portion of the fixation belt pressing surface 108 a , which corresponds in position to the upstream area Nu of the fixation nip N, bulge in circular curvature toward pressure roller 104 , increases the belt backing member 108 (fixation belt pressing surface 108 a ) in the depth of its intrusion into the pressure roller 104 . It therefore increases the upstream area Nu of the fixation nip N in internal pressure, which in turns makes it easier for the toner to melt. Thus, the toner becomes more adherent to the sheet P of recording medium (paper), and also, toner particles increase in the force of mutual adhesion. Therefore, it becomes unlikely for the toner particles on the sheet P to be shifted in position. That is, this secondary effect makes it even more unlikely for the image forming apparatus to output a defective image, the defect of which is attributable to the problem that the toner particles on a sheet of recording medium are made to shift in position by the wrinkling of the fixation belt.
From the standpoint of merely preventing the problem that the wrinkling of the fixation belt of an electrophotographic image forming apparatus makes the apparatus output a defective image, the entire portion of the fixation belt pressing surface 108 a of the belt backing member 108 , in the fixation nip N, may be made to bulge in circular curvature toward the pressure roller 104 , like in the upstream area Nu. However, such a structural arrangement makes it difficult for a sheet P of recording medium (paper) to separate from the outward surface of the fixation belt 100 .
In this embodiment, therefore, the fixation belt pressing surface 108 a is shaped so that its portion in the upstream area Nu of the fixation nip N, which is necessary to prevent the image forming apparatus from outputting a defective image, the defects of which is attributable to the wrinkling of the outward surface layer of the fixation belt 100 , bulges toward the pressure roller 104 in the above described curvature, and its portion in the downstream area Nd in the fixation nip N concaves in the above described curvature to ensure a sheet of recording medium (paper) separates from the outward surface of the fixation belt 100 .
In order to ensure that a sheet of recording medium (paper) separates from the outward surface of the fixation belt 100 , the fixation belt pressing surface 108 a of the belt backing member 108 (fixation nip N) has to be shaped so that when the sheet comes out of the fixation nip N, the downstream portion of the sheet is directed away from the fixation belt 100 (toward pressure roller 104 ), and the fixation belt 100 is guided away from the pressure roller 104 .
Therefore, the inventors of the present invention built a fixing device structured so that the belt backing member 108 is displaced downward in terms of the belt movement direction (to position the rotational axis of the fixation belt 100 downstream relative to the rotational axis of the pressure roller 104 by a distance Wa in terms of the belt movement direction) to optimize the fixing device B in terms of the state of separation of a sheet of recording medium (paper) from the outward surface of the fixation belt 100 . Then, the fixing device was used to study this structural arrangement. The results of the study confirmed that in the case of a fixing device such as the fixing device B in this embodiment structured as described above, providing a distance of 1 mm between the exit Nout of the fixation nip N and the downstream edge 108 ae of the area of contact between the fixation belt pressing surface 108 a and fixation belt 100 makes a sheet of recording medium (paper) naturally separate from the outward surface of the fixation belt 100 .
FIG. 7 is an enlarged view, which was obtained with a microscope, of a part of a fixed solid monochromatic cyan image formed on a sheet of recording paper with the use of a full-color laser printer which employs the fixing device B in this embodiment. It is obvious from the comparison between FIGS. 7 and 16 that the image in FIG. 7 does not show any sign of the image defect called “cracking”.
[Embodiment 2]
Next, another embodiment of the present invention is described. The fixing device B in this embodiment is also of the belt-based heating method. However, this fixing device B employs a ceramic heater (heat generating member) as a heat source. The fixing device B in this embodiment is virtually the same as the fixing device in the first embodiment, except that its heater 118 doubles as the belt backing member 108 in the first embodiment, and some of the structural components of this fixing device B are different in measurements or the like attributes.
(1) Fixing Device
FIG. 8 is a schematic cross-sectional view of the fixing device B in this embodiment. It shows the general structure of the device B. FIG. 9( a ) is a schematic side view of the fixing device B in this embodiment, as seen from the upstream side of the device in terms of the recording conveyance direction, and shows the general structure of the device B, and FIG. 9( b ) is a schematic vertical sectional view of the fixing device B shown in FIG. 9( a ), and shows the general structure of the device B. FIG. 10 is a schematic view of the ceramic heater 118 in this embodiment, as seen from the center of the fixation belt loop, and shows the general structure of the heater 118 .
(1-1) Overall Structure of Fixing Device B
Referring to FIG. 8 , a referential code 100 stands for a fixation belt in this embodiment. The substrative layer 112 of this fixation belt 100 is 34 μm in thickness. Its material is SUS. The outward surface of the substrative layer 112 is covered with an elastic layer 113 formed of silicone rubber. In this embodiment, the thickness of this silicone rubber layer is 275 μm. Further, the outward surface of the elastic layer 113 is covered with a parting layer 114 formed of PFA, which is 30 μm in thickness. In this embodiment, the external diameter of the fixation belt 100 is 25 mm.
The heater 118 is attached to the bottom surface of the belt guide 110 . It has a long and narrow substrate 118 b , which is formed in a preset shape, of a metallic substance such as aluminum, iron, copper, or the like. The heater 118 has also an unshown insulating layer formed by hardening the heat resistant resin, such as polyimide, coated on the back surface, that is, the opposite surface of the substrate 118 b from the fixation nip N. Further, the heater 118 has a heat generating layer 118 c formed on the insulating layer, of electrically resistive substance, by screen-printing paste of Ag/Pd, RuO 2 , Ta 2 N, or the like on the insulating layer to a thickness of roughly 100 μm, and baking the printed layer.
One of the lengthwise ends of the heat generating layer 118 c is in electrical connection with the electrode 118 e 1 through an electrically conductive portion 118 d 1 . As for the other lengthwise end of the heat generating layer 118 c , it is in electrical connection to the electrode 118 e 2 through the electrically conductive portion 118 d 2 . Each of the electrodes 118 e 1 and 118 e 2 is in connection to a pair of electric power supply connectors (unshown), one for one, so that the electrical power is supplied to the heat generating layer 118 b from an electric power supply control circuit 201 through a pair of the power supply connectors.
The heater 118 is supported, along with the belt guide 101 , by the recessed portions 102 a 4 and 102 b 4 of the base portions 102 a 1 and 102 b 1 of the flange 102 a and 102 b , respectively. Further, this heater 118 has a fixation belt pressing surface 118 a . The fixing device B is structured so that this fixation belt pressing surface 118 a is pressed on the inward surface of the fixation belt 100 to form the fixation nip N. The shape of this fixation belt 118 a will be described later in detail.
The pressure bearing portions 102 a 3 and 102 b 3 of the flanges 102 a and 102 b are under 150 N of pressure applied to the pressure application referential surfaces 117 a and 117 b by a pair of coil springs 116 a and 116 b in the direction indicated by arrow marks Pa and Pb, respectively. The flanges 102 a and 102 b are kept pressed toward the pressure roller 104 by the pressure generated by the pair of coil springs 116 a and 116 b . Thus, the fixation belt pressing surface 118 a of the heater 118 presses on the inward surface of the fixation belt 100 , keeping thereby the outward surface of the fixation belt 100 in contact with the peripheral surface of the pressure roller 104 .
As the outward surface of the fixation belt 100 is pressed upon the peripheral surface of the pressure roller 104 , the rubber layer 106 of the pressure roller 104 is elastically compressed. Consequently, the fixation nip N, which has a preset width, is formed between the outward surface of the fixation belt 100 and the peripheral surface of the pressure roller 104 . In this embodiment, the width of the fixation nip N is 6.0 mm.
Like in the case of the first embodiment, the inward surface of the fixation belt 100 is covered with an unshown coated layer of a slippery substance to minimize the friction between the fixation belt 100 and the friction reducing sheet 109 . This coated layer is formed of polyimide, and its thickness is no more than 10 μm.
In order to prevent the pressure roller 104 from robbing an excessive amount of heat from the fixation belt 100 , the pressure roller 104 is desired to be low in thermal capacity and thermal conductivity. The pressure roller 104 is 20 mm in external diameter. It is made up of a metallic core 105 , an elastic layer 106 (silicone rubber layer), and a parting layer 107 . The metallic core is formed of SUS. The elastic layer 106 is formed on the peripheral surface of the metallic core 105 , and is 3.5 mm in thickness. The parting layer 107 is formed, as the outermost layer, on the outward surface of the elastic layer 106 . It is formed of PFA, and is 65 μm in thickness.
(1-2) Driving and Temperature Control of Fixing Device B
The control section C rotationally drives a motor ( FIG. 8 ) M as a driving force source, in response to a print command. The rotation of the output shaft of the motor M is transmitted to a driving gear (unshown) attached to one of the lengthwise ends of the metallic core 105 , through a gear train (unshown). Thus, the pressure roller 104 rotates at a preset peripheral velocity in the direction indicated by an arrow mark. In this embodiment, the pressure roller 104 is rotated at a peripheral velocity of 200 mm/sec.
The rotation of this pressure roller 104 is transferred, as belt driving force, to the fixation belt 100 by the friction between the peripheral surface of the pressure roller 104 and the outward surface of the fixation belt 100 , in the fixation nip N. Thus, the fixation belt 100 is rotated by the rotation of the pressure roller 104 , remaining in contact with the friction reducing sheet 109 by its inward surface.
Further, the control section C drives a triac 201 in response to the print command. As the triac 201 is driven, electric power is supplied to the heat generating layer 118 c from a commercial electric power source (unshown). As the heat generating layer 108 c receives electric power, it generates heat. Thus, the heater 118 quickly increases in temperature, and heats the fixation belt 100 from the inward side of the fixation belt loop.
The temperature of the fixation belt 100 is detected by a temperature detecting member S, such as a thermistor, which is placed in the adjacencies of, or in contact with, the outward surface of the fixation belt 100 . Then, the signals outputted by the temperature detecting member S are taken in by the control section C. Then, the control section C decides the duty ratio for the voltage to be applied to the heat generating layer 118 c , and controls the triac 201 to keep the temperature of the heater 118 at a preset level (fixation temperature; target temperature).
While the motor M is rotationally driven, and the heater 118 is being supplied with electric power, a sheet P of recording medium, on which an unfixed toner image is present, is introduced into the fixation nip N, in such an attitude that the image bearing surface of the sheet P faces the fixation belt 100 . Then, the sheet P is conveyed through the fixation nip N, remaining sandwiched between the outward surface of the fixation belt 100 and the peripheral surface of the pressure roller 104 . While the sheet P is conveyed through the fixation nip N, the unfixed toner image on the sheet P is heated by the heat of the fixation belt 100 , and subjected to the internal pressure of the fixation nip N. Thus, the unfixed toner image on the sheet P becomes fixed to the sheet P. Then, the sheet P is conveyed out of the fixation nip N. Then, the sheet P is discharged from the fixing device B in such a manner that the toner image bearing surface of the sheet P separates from the outward surface of the fixation belt 100 .
(2) Shape of Fixation Belt Pressing Surface 118 a of Heater 118
FIG. 11 is a schematic cross-sectional view of the fixation nip N, and its adjacencies, of the fixing device B in this embodiment, and shows the general structure of the fixation nip N and its adjacencies. In order to make it easier to recognize the shape of the fixation belt pressing surface 118 a of the heater 118 , the belt guide 101 and friction reducing sheet 109 are not illustrated in FIG. 11 .
Referring to FIG. 11 , the nip forming surface 118 a is the same in basic shape as the counterpart in the first embodiment. That is, in terms of the cross-sectional shape of the fixation belt pressing surface 118 a of the heater 118 , the heater 118 is shaped so that the portion of the fixation belt pressing surface 118 a of the heater 118 , which is in the upstream portion of the fixation nip N bulges in circular curvature toward the pressure roller 104 , whereas the portion of the fixation belt pressing surface 118 a , which is in downstream portion of the fixation nip N, concaves in curvature toward the heat generating layer 118 c.
Concretely, referring to FIG. 11 , the portion of the fixation belt pressing surface 118 a , which bulges in circular curvature is 5.0 mm in width, and the portion of the fixation belt pressing surface 118 a , which concaves in curvature, is 2.4 mm in width. Therefore, of the portion of the fixation belt pressing surface 118 a (fixation nip forming surface) in the fixation nip N which is 6.0 mm in width, the upstream portion which bulges in circular curvature is 4.0 mm in width, and the rest, that is, the downstream portion, which concaves in curvature, is 2.0 mm in width.
That is, in terms of the cross-section shape of the portion of the heater 118 in the fixation nip N, the fixation belt pressing surface 118 a of the heater 118 , which is in the upstream area Nu relative to the center Nc of the fixation nip N in terms of the recording medium conveyance direction, bulges in circular curvature toward the pressure roller 104 , whereas the fixation belt pressing surface 118 a of the heater 118 , which is in the downstream area Nd, which is the area between the downstream edge Nut of the upstream area Nu and the downstream edge of the fixation nip N, in terms of the rotational direction of the fixation belt 100 , concaves in curvature toward the heat generating layer 118 c . In FIG. 11 , a referential code 118 ae stands for the most downstream edge of the area of contact between the fixation belt pressing surface 118 a and fixation belt 100 in terms of the rotational direction of the fixation belt 100 .
In the case of the fixing device B in this embodiment, the external diameter of the fixation belt 100 is 25 mm (R 12 . 5 ). Therefore, the circular curvature in which the fixation belt pressing surface 118 a bulges in the upstream area Nu in the fixation nip N is made to be R 12 . 5 . Here, the relationship between the radius R 1 of the circular curvature in which the fixation belt pressing surface 118 a bulges and the radius R 2 of the fixation belt 100 is: R 1 =R 2 . Further, the curvature in which the fixation belt pressing surface 118 a concaves in the downstream area Nd was set also to R 12 . 5 to ensure that a sheet of recording paper satisfactorily separates from the outward surface of the fixation belt 100 as in the first embodiment.
Shown in FIG. 12 is the change in the amount of compression of the parting layer 114 , or the outward surface layer of the fixation belt 100 , which occurs in the fixation nip N. Because the fixing device B in this embodiment is structured as described above, the amount of the compression of the parting layer 114 , which occurs in the upstream area Nu of the fixation nip N relative to the center Nc of the fixation nip N is zero. Therefore, the occurrence of the image defect is significantly suppressed.
Embodiment 3
Next, another embodiment of the present invention is described. In the case of the fixing device B in the first embodiment, the circular curvature in which the fixation belt pressing surface 108 a of the belt backing member 108 is made to bulge toward the pressure roller 104 in the upstream area Nu of the fixation nip N is the same as the curvature of the fixation belt 100 . However, the former may be different from the latter. In this embodiment, therefore, the former is made different from the latter. Otherwise, the fixing device B in this embodiment is the same in structure as the fixation device B in the first embodiment.
FIG. 13 is a schematic cross-sectional view of the fixation nip N, and its adjacencies, of the fixing device B in this embodiment. It shows the general structure of the fixation nip N and its adjacencies.
Referring to FIG. 13 , in the case of the fixing device B in this embodiment, the radius of the fixation belt 100 is R 15 , and the circular curvature in which the fixation belt pressing surface 108 a of the belt backing member 108 is made to bulge in the fixation nip N toward the pressure roller 104 is R 12 in radius, whereas the circular curvature in which the fixation belt pressing surface 108 a is made to concave in the downstream area Nd of the fixation nip is R 17 . 5 which is the same as in the first embodiment.
Shown in FIG. 14 is the changes in the amount of compression of the outward surface layer of the fixation belt 100 , which occur in the fixation nip N of the fixing device B in this embodiment.
In the case of the fixing device B in this embodiment, the circular curvature in which the fixation belt pressing surface 108 a bulges in the upstream area Nu of the fixation nip N is R 12 in radius, which is smaller than the radius R 15 of the fixation belt 100 . Thus, the relationship between the radiuses R 1 and R 2 is: R 1 <R 2 . Based on Equation (1), therefore, the amount by which the parting layer 114 , which is the outward surface layer of the fixation belt 100 , is compressed is negative. That is, the parting layer 114 is extended in the fixation nip N.
Therefore, the fixing device B in this embodiment has the same effect as the effect which the fixing device B in the first embodiment has. Further, making the circular curvature in which the fixation belt pressing surface 108 a of the fixing device B in the second embodiment bulges in the upstream area Nu of the fixation nip N smaller in radius than the fixation belt 100 has the same effect.
[Embodiment 4]
Next, another embodiment of the present invention is described. FIG. 15 is a schematic cross-sectional view of the fixation nip N, and its adjacencies, of the fixing device B in this embodiment. It shows the general structure of the fixation nip N and its adjacencies. FIG. 15( a ) represents a case in which the portion of the fixation belt pressing surface 108 a , which is in the downstream area Nd of the fixation nip N, is flat, and FIG. 15( b ) represents a case in which the portion of the fixation belt pressing surface 108 a , which is in the downstream area Nd of the fixation nip N, is a combination of a flat portion and a concave portion.
As is evident from the description of the first embodiment, all that is necessary to suppress the occurrence of the above described defective image is to make at least the portion of the fixation belt pressing surface 108 a of the belt backing member 108 , which is the upstream area Nu of the fixation nip N relative to the center Nc of the fixation nip N in terms of the rotational direction f the fixation belt 100 , bulge in circular curvature. As for the shape of the portion of the fixation belt pressing surface 108 a , which is in the downstream area Nd of the fixation nip N, it does not need to be made to concave in circular curvature as it is in the first and second embodiments, as long as it can ensure that a sheet of recording paper separates from the outward surface of the fixation belt 100 . Therefore, the portion of the fixation belt pressing surface 108 a , which is in the downstream area Nd of the fixation nip N, may be flat as shown in FIG. 15( a ), or a combination of a portion which is flat, and a portion which bulges in circular curvature as shown in FIG. 15( b ).
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims priority from Japanese Patent Application No. 003235/2013 filed Jan. 11, 2013 which is hereby incorporated by reference. | A fixing apparatus includes a back-up member contacting an inner surface of a cylindrical belt; a roller having an elastic layer and contacting an outer surface of the belt, the roller being cooperative with the back-up member to form a fixing nip between the belt and the roller. A sheet carrying a toner image is nipped and fed through the fixing nip, during which the unfixed toner image is heat-fixed thereon by the fixing nip. The back-up member includes a portion contactable with the inner surface and having such a configuration that the belt forms a first curved surface convex toward the roller in an upstream region in the fixing nip with respect to a moving direction of the belt and that the belt forms a second curved surface convex toward the back-up member in a downstream region in the fixing nip with respect to the moving direction. | Summarize the patent document, focusing on the invention's functionality and advantages. | [
"FIELD OF THE INVENTION AND RELATED ART The present invention relates to a fixing apparatus (device) which is mounted in an image forming apparatus such as an electrophotographic copying machine, an electrophotographic printer, etc.",
"A fixing apparatus (fixing device) which is to be mounted in an electrophotographic copying machine, an electrophotographic printer, and the like is desired to start up as quickly as possible, and also, to be as small in energy consumption as possible.",
"Thus, a fixing device which employs a fixing belt has been put to practical use.",
"A fixing device of this type has: a cylindrical fixation belt;",
"a belt backing member, which is disposed on the inward side of the fixation belt loop;",
"a pressure roller which forms a nip by being pressed against the belt backing member with the placement of the fixation belt between itself and belt backing member;",
"etc.",
"A sheet of recording medium which is bearing an unfixed toner image is conveyed through the nip while being heated in the nip.",
"Thus, the toner image on the sheet P of recording medium becomes fixed to the sheet of recording medium.",
"There are various methods for heating a fixation belt.",
"For example, there are a heating method which employs a heat generating flat member such as a ceramic heater, a heating method which employs a heating means based on electromagnetic induction, and the like, which are proposed in Japanese Laid-open Patent application No. 2009-98357, Japanese Patent No. 3,807,223, and Japanese Laid-open Patent Application No. H10-321352.",
"However, a fixing device, such as the one describe above, which employs a belt backing member to form a nip, is problematic in that it is likely to output a defective image, the defect of which is referred to as “cracking.”",
"FIG. 16 is a magnified image of a “cracked”",
"image, which was obtained with the use of a microscope.",
"This “cracked”",
"image was outputted by a fixing device, which employs a fixation belt, when the fixing device was used to fix a solid monochromatic image of cyan color to a sheet of recording paper (which hereafter may be referred to simply as sheet of paper).",
"As is evident from FIG. 16 , “cracking”",
"is an image defect attributable to a phenomenon that as the toner particles, of which an unfixed image on a sheet of recording medium (paper) shift in position, the portions of the sheet, which were under the toner particles, become exposed.",
"The primary cause of this image defect is the “wrinkles”",
"which occur to the outward surface layer (parting layer) of a fixation belt.",
"That is, the “wrinkles”",
"are attributable to the displacement of the unfixed toner particles by the wrinkling of the outward surface layer of the fixation belt.",
"It is on the upstream side of the fixation nip, in terms of the recording medium conveyance direction in the fixation nip, that the toner particle displacement occurs.",
"As for the reason for the toner particle displacement, when a given portion of a sheet of paper, on which an unfixed toner image is present, is in the upstream portion of the fixation nip, the toner particles on this portion of the sheet, will not have substantially melted.",
"Therefore, they are weak in their adhesiveness to the sheet, and in the adhesiveness among them in this portion of the sheet.",
"Therefore, they are likely to be shifted in position by the wrinkling of the outward surface layer of the fixation belt.",
"In comparison, in the downstream side of the fixation nip in terms of the recording medium conveyance direction, the toner particles on the sheet will have substantially melted.",
"Therefore, even if the outward surface layer of the fixation belt is wrinkled, it hardly occurs that the toner particles are displaced by the wrinkling of the outward surface layer of the fixation roller.",
"The “wrinkling”",
"of the outward surface layer of a fixation belt occurs as the outward surface layer of the fixation belt is compressed in such a manner that the outward surface is concavely bent, or it becomes flat.",
"As will be described later, as a given portion of a fixation belt, in terms of the moving direction of the fixation belt, is moved into a fixation nip, it is deformed by the combination of a belt backing member, and a pressure roller, against which the fixation belt is pressed by the belt backing member.",
"Thus, in terms of its vertical cross-section, which is parallel to the moving direction of the fixation belt, the shape of the portion of the fixation belt in the fixation nip is determined by the shape of the belt backing member.",
"Thus, as the outward surface layer of the fixation belt is changed in shape by the belt backing member as described above, wrinkles occur to the outward surface layer of the fixation belt.",
"Next, referring to FIGS. 17( a ), 17 ( b ) and 17 ( c ), the mechanism of the wrinkling of the outward surface layer of the fixation belt is described.",
"FIG. 17( a ) is a schematic cross-sectional view of a section of the fixation belt, when the fixation belt is under no pressure.",
"In FIG. 17( a ), the portion outlined by a solid line (which corresponds to angle θ) is equivalent to the portion of the fixation belt, which is in the fixation nip when the fixation belt is under the pressure.",
"Referring to FIG. 17( a ), referential codes Le and Li stand for the length of the outward and inward surfaces, respectively, of the portion of the surface layers of the fixation layer in the fixation nip.",
"Referential codes Re and Ri stand for the radius of the outward surface of the outward surface layer of the fixation belt, and the inward surface of the fixation belt, respectively.",
"Further, a referential code W stands for the thickness of the fixation belt (W=Re−Ri).",
"FIG. 17( b ) is a schematic cross-sectional view of the portion of the fixation belt, which is shown in FIG. 17( a ), when the portion is in the fixation nip, having thereby been flattened by being pressed upon an unshown belt backing member by an unshown pressure roller.",
"In FIG. 17( b ), referential codes Le′ and Li′ stand for the length of the outward surface of the portion outlined by the solid line, and the length of the inward surface of the portion outlined by the solid line, respectively.",
"The length Le′ has no direct relation to the wrinkling of the portion.",
"It is the direct distance between points A and B in FIG. 17( b ) that has direct relationship to the wrinkling.",
"FIG. 17( c ) is a schematic cross-sectional view of the portion of the fixation belt, which is shown in FIG. 17( b ), when the portion is in the fixation nip, having thereby been made to be concave in circular curvature, that is, deformed in such a manner that its is reversed in curvature from when it is in the state shown in FIG. 17( a ).",
"Also in FIG. 17( c ), referential codes Le′ and Li′ stand for the length of the outward surface of the portion outlined by the solid line, and the length of the inward surface of the portion outlined by the solid line, respectively.",
"The length Le′ has no direct relation to the wrinkling of the portion.",
"It is the direct distance between points A and B in FIG. 17( c ) that has direct relation to the wrinkling.",
"First, a case in which a given portion of the fixation belt is flattened in the fixation nip as shown in FIG. 17( b ) is described.",
"As a portion of the fixation belt, the curvature of which is as shown in FIG. 17( a ) is flattened as shown in FIG. 17( b ), the inward surface of the fixation belt is slightly stretched, whereas the outward surface of the fixation belt is compressed by such an amount that makes its length roughly the same as the length of the stretched inward surface of the fixation belt.",
"Generally speaking, a fixation belt is provided with a parting layer, which makes up the actual outward surface layer of the fixation belt, as will be described later.",
"The parting layer cannot be easily compressed.",
"Thus, as it is subjected to compressive force, it fails to be compressed.",
"Consequently, it is wrinkled.",
"Here, the amount of difference between the pre-deformation length of the outward surface layer of the fixation belt and the post-deformation length of the outward surface layer of the fixation belt is referred to as the amount of fixation belt compression or fixation belt compression amount.",
"The amount of fixation belt compression is expressible in the form of the following Equation (1).",
"Amount of compression= Le−Le′ (1) In a case where a given portion of the fixation belt is flattened in the fixation nip, the length Le′, that is, the length of the outward surface of the given portion after the deformation of the portion, is the same as the length Le′, that is, the length of the inward surface of the given portion after the deformation.",
"The dimension of the fixation nip in terms of the circumferential direction of the fixation belt, is very small relative to the circumference of the fixation belt.",
"Thus, the angle θ is very small relative to 360° which corresponds to the circumference of the fixation belt.",
"Therefore, it is reasonable to say that the length Li, which is the pre-deformation length of the inward surface of the given portion of the fixation belt is roughly the same as the length Li,′ that is, the post-deformation length of the inward surface of the given portion of the fixation belt.",
"Thus, Equation (1) which shows the amount of fixation belt compression may be rewritten as follows: Amount of Compression= Le−Le′=Le−Li′≈Le−Li (2) Further, the length Le, or the pre-deformation length of the outward surface layer of the fixation belt, can be obtained from the radius Re of the outward surface layer of the fixation belt and the angle θ of the sector of the cross-section of the fixation belt: Le=θ×Re.",
"Similarly, the length Li, or the pre-deformation length of the inward surface of the given portion of the fixation belt, can be obtained from the radius Ri and the angle θ: Li=θ×Ri.",
"Thus, Equation (2) can be rewritten as follows: Amount of Compression ∝ θ × Re - θ × Ri = θ × ( Re - Ri ) = θ W .",
"( 3 ) A letter W stands for the thickness of the fixation belt as described above.",
"As is evident from Equation (3), the amount of the compression of the fixation belt is proportional to the thickness W of the fixation belt.",
"The greater the amount of the fixation belt compression, the greater the extent of the wrinkling of the outward surface layer of the fixation belt.",
"Therefore, in a case where a given portion of the fixation belt is flattened in the fixation nip, the thicker the fixation belt, (as fixation belt is increased in thickness W), the greater the extent of the wrinkling of the outward surface layer of the fixation belt (surface layer of fixation belt wrinkles more), and therefore, the greater the extent of the image defect called “cracking.”",
"Next, referring to FIG. 17( c ), a case in which a given portion of the fixation belt is bent in the fixation nip in such a shape that it is made to concave toward the rotational axis of the fixation belt, that is, it is reversed in curvature from when it is in the state shown in FIG. 17( a ), is described.",
"As the given portion, the curvature of which was as shown in FIG. 17( a ), is bent so that its curvature becomes as shown in FIG. 17( c ), the inward surface of the fixation belt is stretched, but, the outward surface layer of the fixation belt is compressed.",
"Thus, the outward surface layer of the fixation belt is made to wrinkle for the same reason as the one given above.",
"Also in this case, the “amount of compression”",
"which is the difference between the pre-deformation length of the surface layer of a given portion of the fixation belt and the post-deformation length of the surface layer of the given portion of the fixation belt can be defined as in the case where the given portion is deformed as shown in FIG. 17( b ).",
"Referring to FIG. 17( c ), the given portion of the fixation belt is deformed in such a shape that its curvature equals a circle, the radius of which is Rc, and the length of which is equivalent to the angle θ′ of this circle, the “amount of compression”",
"can be expressed in the form of the following Equation.",
"Amount of Compression = Le - Le ′ = θ × Re - θ ′ × ( Rc - W ) = θ ′ Re - θ ′ Rc + θ ′ W .",
"( 4 ) Based on Equation (4), even in a case where a given portion of the fixation belt is deformed in such a manner that it is made to concave, the thicker the fixation belt, the greater the amount of compression of the given portion, and therefore, the greater the extent of the wrinkling of the outward surface layer of the fixation belt.",
"From Equation (4), the smaller the given portion in the post-deformation radius Rc (greater in curvature), the greater the amount of compression, and therefore, the greater it will be in the extent of wrinkling.",
"Therefore, the greater it will be in the extent of the image defect which is referred to as “cracking.”",
"As will be evident from the foregoing, as a given portion of the fixation belt, the curvature of which is as shown in FIG. 17( a ), is flattened or reversed in curvature as shown in FIGS. 17( b ) and 17 ( c ), respectively, the surface layer of this portion of the fixation belt is compressed, being therefore reduced in length.",
"Therefore, it becomes positive in the amount of compression, which is calculable with the use of Equation (1).",
"In comparison, in a case where the given portion of the fixation belt is stretched as it is deformed, it becomes positive in the amount of compression which is obtainable with the use of Equation (1), although this case is not illustrated here.",
"In other words, in a case where the amount of compression is positive, the fixation belt wrinkles, and the greater the amount of compression, the greater the extent of wrinkling.",
"The greater the extent of wrinkling, the more serious, the image defect attributable to the wrinkling of the fixation belt.",
"On the other hand, in a case where the amount of compression is negative, the fixation belt does not wrinkle.",
"Therefore, the image defect attributable to the wrinkling of the fixation belt hardly occurs.",
"As will be evident from the foregoing description, the thicker the fixation belt, the greater it is in the difference between its internal (substrative layer) external diameters (surface layer), and therefore, the greater it is in the extent of wrinkling, or the vertical distance between the highest point of its peak and the bottom of its valley.",
"In recent years, a copying machine, a printer, and the like devices have come to be desired to be substantially increased in speed.",
"Thus, in order to ensure that they remain satisfactory in image quality (fixation, in particular) in spite of increase in speed, they have been substantially increased in the thickness of the elastic layer of their fixation belt, as will be described later.",
"Consequently, they have become substantially larger in the difference between the internal and external diameters of their fixation belt.",
"Thus, it is reasonable to think that the issues related to the image defect, which is referred to as “cracking”, will become one of the greater concerns.",
"Further, it is also to be ensured that a sheet of recording medium easily separates from a fixation belt.",
"SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing apparatus with which image defects attributable to the crease of the belt surface layer can be suppressed, and a separation of the recording material is easy.",
"According to an aspect of the present invention, there is provided a fixing apparatus comprising a cylindrical belt;",
"a back-up member contacting an inner surface of said belt;",
"a roller contacting an outer surface of said belt, said roller being provided with an elastic layer, said roller being cooperative with said back-up member to sandwich said belt and form a fixing nip between said belt and said roller;",
"wherein a recording material carrying an unfixed toner image is nipped and fed through the fixing nip, during which the unfixed toner image on the recording material is heated and fixed thereon by the fixing nip, and wherein said back-up member includes a portion contactable with the inner surface of said belt, the portion having such a configuration that said belt forms a first curved surface which is substantially convex toward said roller in an upstream region in said fixing nip with respect to a moving direction of said belt and that said belt forms a second curved surface which is substantially convex toward said back-up member in a downstream region in said fixing nip with respect to the moving direction.",
"Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view of a typical image forming apparatus to which the present invention is applicable, and shows the general structure of the apparatus.",
"FIG. 2 is a schematic cross-sectional view of the fixing device in the first embodiment of the present invention, and shows the general structure of the device.",
"FIG. 3( a ) is a schematic side view of the fixing device in the first embodiment, as seen from the upstream side of the device in terms of the recording conveyance direction, and shows the general structure of the device, and FIG. 3( b ) is a schematic vertical sectional view of the fixing device shown in FIG. 3( a ), and shows the general structure of the device.",
"FIG. 4 is a schematic sectional view of the fixation belt of the fixing device in the first embodiment, and shows the laminar structure of the belt.",
"FIG. 5 is a schematic cross-sectional view of the fixation nip, and its adjacencies, of the fixing device in the first embodiment, and shows the general structure of the fixation nip and its adjacencies.",
"FIG. 6 is a schematic drawing for showing the amount of compression of the outward surface layer of the fixation belt of the fixing device in the first embodiment, in the fixation nip.",
"FIG. 7 is a magnified view of a part of a toner image fixed to a sheet of recording medium by the fixing device in the first embodiment, which was obtained with the use of a microscope.",
"FIG. 8 is a schematic cross-sectional view of the fixing device in the second embodiment of the present invention, and shows the general structure of the device.",
"In FIG. 9 , ( a ) is a schematic side view of the fixing device in the second embodiment, as seen from the upstream side of the device in terms of the recording conveyance direction, and shows the general structure of the device, and ( b ) is a schematic vertical sectional view of the fixing device shown in FIG. 9( a ), and shows the general structure of the device.",
"FIG. 10 is a rear view of the ceramic heater of the fixing device in the second embodiment, and shows the general structure of the ceramic heater.",
"FIG. 11 is a schematic cross-sectional view of the fixation nip, and its adjacencies, of the fixing device in the second embodiment, and shows the general structure of the fixation nip and its adjacencies.",
"FIG. 12 is a schematic drawing for showing the amount of compression of the outward surface layer of the fixation belt of the fixing device in the second embodiment, in the fixation nip.",
"FIG. 13 is a schematic sectional view of the fixation nip, and its adjacencies, of the fixing device in the third embodiment, and shows the general structure of the fixation nip and its adjacencies.",
"FIG. 14 is a schematic drawing for showing the amount of compression of the outward surface layer of the fixation belt of the fixing device in the third embodiment, in the fixation nip.",
"FIG. 15 is a schematic cross-sectional view of the fixation nip, and its adjacencies, of the fixing device in the fourth embodiment, and shows the general structure of the fixation nip and its adjacencies.",
"FIG. 16 is a magnified view of a part of a toner image fixed to a sheet of recording medium by a conventional fixing device, which was obtained with the use of a microscope.",
"FIG. 17 is a schematic drawing for explaining the principle, based on which the surface layer of a fixation belt wrinkles.",
"DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention is described in detail with reference to the appended drawings.",
"[Embodiment 1] (1) Example of Image Forming Apparatus FIG. 1 is a schematic sectional view of a typical image forming apparatus which employs a fixing device which is in accordance with the present invention.",
"It shows the general structure of the apparatus.",
"This image forming apparatus is a full-color laser beam printer which uses an electrophotographic image forming method.",
"It is structured so that a sheet of recording medium is conveyed through the apparatus in such a manner that, in terms of the direction perpendicular to the recording medium conveyance direction of the apparatus, the center of the sheet of recording medium coincides with the center CL ( FIG. 3( a )) of the recording medium passage of the apparatus.",
"The image forming apparatus in this embodiment has: an image formation section A which forms an unfixed toner image (image) on a sheet P of recording medium;",
"a fixation section B which fixes the unfixed toner image on the sheet P of recording medium, to the sheet P;",
"a control section C which controls the entirety of the apparatus;",
"etc.",
"The image formation section A has: four image formation stations Pa, Pb, Pc and Pd, which form cyan, magenta, yellow, and black monochromatic images, respectively;",
"an intermediary transfer belt 7 ;",
"etc.",
"The control section C is made up of a CPU, and memories such as a ROM and a RAM.",
"The memories store image formation sequences, various tables necessary for image formation, etc.",
"The image formation stations Pa, Pb, Pc and Pd have developing devices (developing means) 1 a , 1 b , 1 c and 1 d , which have toner containers 1 a 1 , 1 b 1 , 1 c 1 and 1 d 1 and development rollers 1 a 2 , 1 b 2 , 1 c 2 and 1 d 2 , etc.",
", which contain cyan, magenta, yellow, and black toners, respectively.",
"The image forming operation of the image forming apparatus in this embodiment is as follows.",
"As the control section C receives a print command from an external apparatus (unshown) such as a host computer, it carries out an image formation control sequence.",
"As the image formation sequence is started, the electrophotographic photosensitive members 3 a , 3 b , 3 c and 3 d (which are in the form of a drum, and therefore, will be referred to simply as photosensitive drum, hereafter), in the image formation stations Pa, Pb, Pc and Pd, respectively, are rotated in the direction indicated by arrow marks at a preset peripheral velocity (process speed).",
"Further, the intermediary transfer belt 7 , which is below the combination of the image formation stations Pa, Pb, Pc and Pd, and is stretched around the combination of three rollers, more specifically, a driver roller 8 , a belt backing roller 9 which opposes a secondary transfer roller, and a tension roller 10 , is rotated in the direction indicated by an arrow mark at a peripheral velocity which is equal to the peripheral velocity of the photosensitive drums 3 a , 3 b , 3 c and 3 d. In the image formation station Pa, the peripheral surface of the photosensitive drum 3 a is uniformly charged by a charge roller (charging means) 2 a to preset polarity and potential level (charging process).",
"Then, the uniformly charged portion of the peripheral surface of the photosensitive drum 3 a is scanned by (exposed to) a beam of laser light outputted by a laser-based exposing device (exposing means) 5 , whereby an electrostatic latent image, which is in accordance with the information of the image to be formed, is formed on the peripheral surface of the photosensitive drum 3 a (exposing process).",
"This latent image is developed into a visible image through a process of adhering toner of cyan color, which is in the toner container 1 a 1 of the developing device (developing means) 1 a , to the latent image by the development roller 1 a 2 .",
"Consequently, a toner image of cyan color is formed on the peripheral surface of the photosensitive drum 3 a (developing process).",
"Also in the image formation stations 1 b , 1 c and 1 d , the charging, exposing, and developing processes which are similar to the above described ones carried out in the image formation station 1 a , are carried out.",
"Consequently, a toner image of magenta color, a toner image of yellow color, and a toner image of black color, are formed on the peripheral surface of the photosensitive drum 3 b , peripheral surface of the photosensitive drum 3 c , and peripheral surface of the photosensitive drum 3 d in the image formation stations 1 b , 1 c and 1 d , respectively.",
"The toner image of cyan color on the peripheral surface of the photosensitive drum 3 a is conveyed, by the rotation of the photosensitive drum 3 a , to the first transfer nip formed by the peripheral surface of the photosensitive drum 3 a and the outward surface of the intermediary transfer belt 7 , and then, is conveyed through the first transfer nip.",
"While it is conveyed through the first transfer nip, a preset transfer bias is applied to a primary transfer roller 6 a , which is positioned so that it opposes the photosensitive drum 3 a , with the presence of the intermediary transfer belt 7 between itself and photosensitive drum 3 a .",
"Consequently, the toner image of cyan color on the peripheral surface of the photosensitive drum 3 a is transferred onto the surface of the intermediary transfer belt 7 (primary transferring process).",
"Primary transferring processes (image formation processes) similar to the above described one are carried out in the image formation stations 1 b , 1 c , and 1 d , one for one.",
"That is, as a preset transfer bias is applied to the primary transfer roller 6 b , the toner image of magenta color is transferred onto the intermediary transfer belt 7 in such a manner that it is layered upon the toner image of cyan color on the intermediary transfer belt 7 .",
"Further, a preset transfer bias is applied to the primary transfer roller 6 c , the toner image of yellow color is transferred onto the intermediary transfer belt 7 in such a manner that it is layered upon the toner image of magenta color on the intermediary transfer belt 7 .",
"Moreover, as a preset transfer bias is applied to the primary transfer roller 6 d , the toner image of black color is transferred onto the intermediary transfer belt 7 in such a manner that it is layered upon the toner image of yellow color on the intermediary transfer belt 7 .",
"Consequently, an unfixed full-color is formed of four monochromatic images, different in color, on the surface of the intermediary transfer belt 7 .",
"Then, the unfixed full-color toner image on the intermediary transfer belt 7 is conveyed by the rotation of the intermediary transfer belt 7 to the secondary transfer nip formed by the surface of the intermediary transfer belt 7 , and the peripheral surface of the secondary transfer roller 11 .",
"The secondary transfer roller 11 is positioned so that it sandwiches the intermediary transfer belt 7 between itself and the belt backing roller 8 .",
"The transfer residual toner, that is, the toner remaining on the peripheral surface of the photosensitive drums 3 a , 3 b , 3 c and 3 d after the secondary transfer of the toner images, is removed by cleaning blades (cleaning means) 4 a , 4 b , 4 c and 4 d , which correspond in position to the photosensitive drums 3 a , 3 b , 3 c and 3 d , so that the photosensitive drums 3 a , 3 b , 3 c and 3 d can be used for the following image formation.",
"After the removal of the transfer residual toner by the cleaning blades 4 a , 4 b , 4 c and 4 d , the transfer residual toner is stored in waste toner containers 4 a 1 , 4 b 1 , 4 c 1 and 4 d 1 , respectively.",
"Meanwhile, sheets P of recording medium in a sheet feeder cassette 14 are fed one by one into the main assembly of the image forming apparatus.",
"Then, each sheet P of recording medium is conveyed by a pair of sheet conveyance rollers 16 to a pair of registration rollers 17 , which conveys the sheet P to the secondary transfer nip with a preset timing.",
"Then, the sheet P is conveyed through the secondary transfer nip while remaining pinched by the surface of the intermediary transfer belt 7 and the peripheral surface of the secondary transfer roller 11 .",
"While the sheet P is conveyed through the secondary transfer nip, the unfixed full-color toner image on the surface of the intermediary transfer belt 7 is transferred onto the sheet P by a preset transfer bias applied to the secondary transfer roller 11 (secondary transfer process).",
"Consequently, the unfixed full-color toner image made up of the four monochromatic toner images, different in color, is borne by the sheet P of recording medium.",
"After the transfer of the unfixed full-color toner image from the intermediary transfer belt 7 , the surface of the intermediary transfer belt 7 is rid of the transfer residual toner, by the cleaning web (unwoven cloth) 12 a , to be readied for the next image formation.",
"The removed transfer residual toner is stored in a waste toner container 12 a 1 .",
"The sheet P of recording medium, on which the unfixed full-color toner image is present is introduced into, and conveyed through, the fixation nip N (which will be described later) of the fixing section (which hereafter will be referred to as fixing device) B. While the sheet P is conveyed through the fixation nip N, the unfixed toner image is thermally fixed to the sheet P. Then, the sheet P is moved out of the fixation nip N, is conveyed to the delivery tray 19 , and then, is discharged into the delivery tray 19 .",
"There is present between the fixing device B and delivery tray 19 , a recording medium turning mechanism 18 , which turns the sheet P over so that the image bearing surface of the sheet P is switched in position with the surface of the sheet P which has no image.",
"(2) Fixing Apparatus (Fixing Device) B (2-1) General Structure of Fixing Apparatus B FIG. 2 is a schematic cross-sectional view of the fixing device B in this embodiment.",
"FIG. 3( a ) is a schematic side view of the fixing device B in this embodiment as seen from the upstream side of the device in terms of the recording medium conveyance direction of the device B. It shows the general structure of the device B. FIG. 3( b ) is a schematic vertical sectional view of the fixing device B, shown in FIG. 3( a ).",
"It shows the general structure of the fixing device B. This fixing device B employs a fixation belt which is heated by electromagnetic induction.",
"The fixing device B in this embodiment has a fixation belt (heating belt) 100 , a belt guide (heating belt guide) 101 , and a pressure roller (pressure applying member) 104 .",
"It has also a belt backing member 108 , a friction reducing sheet 109 which guides the fixation belt 100 , a coil unit 110 , etc.",
"The fixation belt 1001 , belt guide 101 , pressure roller 104 , and belt backing member 108 , friction reducing sheet 109 , and coil unit 110 are long and narrow, and their lengthwise direction is perpendicular to the sheet of paper on which FIG. 2 is present.",
"The fixation belt 100 is flexible and cylindrical.",
"It is loosely fitted around a combination of the belt guide 101 and belt backing member 108 .",
"The belt guide 101 is formed of heat resistant resin, such as LCP (Liquid Crystal Polymer).",
"It is roughly in the form of a trough, and is positioned so that its open side faces toward the rotational axis of the fixation belt 100 .",
"The belt backing member 108 is attached to the bottom surface of the belt guide 101 .",
"The fixation belt 100 in this embodiment is 30 mm in external diameter, and its dimension in terms of the direction parallel to the lengthwise direction of the fixing device 100 , is greater than the length of a largest sheet of recording medium, which can be conveyed through the fixing device B ( FIG. 3( a )).",
"Referring to FIGS. 3( a ) and 3 ( b ), the fixing device B is provided with a flange 102 a , which is at one of the lengthwise ends of the fixation belt 100 (left side of FIGS. 3( a ) and 3 ( b )).",
"The flange 102 a has a base portion 102 a 1 , the external diameter of which is greater than the external diameter of the fixation belt 100 .",
"The base portion 101 a 1 has: a belt guide 102 a 2 , which protrudes inward of the fixation belt loop (loop which fixation belt 100 forms);",
"and a pressure bearing portion 102 a 3 which protrudes from the base portion 101 a 1 , in the opposite direction from the belt guide 102 a 2 .",
"The belt guide 102 a 2 is roughly semi-cylindrical, and its radius is less than the internal radius of the fixation belt 100 .",
"It guides the fixation belt 100 to prevent the fixation belt 100 from deviating in the lengthwise direction of the fixing device B, as the belt 100 is rotated.",
"Further, the fixing device B is provided with a flange 102 b , which is at the other lengthwise end (right side of FIGS. 3( a ) and 3 ( b )) of the fixation belt 100 from where the flange 102 a is present.",
"The flange 102 b has a base portion 102 b 1 , the external diameter of which is greater than the external diameter of the fixation belt 100 .",
"The base portion 102 b 1 has: a belt guide 102 b 2 , which protrudes inward of the fixation belt loop;",
"and a pressure bearing portion 102 b 3 which protrudes from the base portion 102 b 1 , in the opposite direction from the belt guide 102 b 2 .",
"The belt guide 102 b 2 is roughly semi-cylindrical, and its radius is less than the internal radius of the fixation belt 100 .",
"It guides the fixation belt 100 to prevent the fixation belt 100 from deviating in the lengthwise direction of the fixing device B, as the belt 100 is rotated.",
"The base portions 102 a 1 and 102 b 1 are provided with recesses 102 a 4 and 102 b 4 ( FIG. 2( b )), which face the pressure roller 104 and extend in the lengthwise direction of the fixation belt 100 .",
"The belt guide 101 and belt backing member are fitted in these recesses 102 a 4 and 102 b 4 , being thereby supported by their lengthwise ends, by the base portions 102 a 1 and 102 b 1 .",
"The base portions 102 a 1 and 102 b 1 of the flanges 102 a and 102 b , which are positioned at the lengthwise ends of the fixation belt 100 , one for one, are supported by the lateral plates Fa and Fb of the frame (unshown) of the fixing device B, respectively, in such a manner that they can be vertically moved.",
"The pressure roller 104 has: a metallic core 105 ;",
"a rubber layer (elastic layer) 106 , which covers the entirety of the peripheral surface of the metallic core 105 , except for the lengthwise end portions 105 a and 105 b of the metallic core 105 ;",
"a parting layer 107 which covers the peripheral surface of the rubber layer 106 ;",
"etc.",
"In this embodiment, the material for the metallic core is SUS (steel use stainless).",
"The material for the rubber layer 106 is silicone rubber or the like.",
"The parting layer 107 is formed of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA).",
"The diameter of the pressure roller 104 in this embodiment is 24 mm.",
"In terms of the direction parallel to the recording medium conveyance direction, the above described pressure roller 104 is disposed so that a vertical line Vr which coincides with the rotational axis of the pressure roller 104 and is perpendicular to the generatrix of the pressure roller 104 , is on the upstream side of the vertical line Vb which coincides with the rotational axis of the fixation belt 100 and is perpendicular to the generatrix of the fixation belt 100 , being separated by a preset width Wa ( FIG. 2 ).",
"This pressure roller 104 , and the belt backing member 108 which is on the inward side of the fixation belt loop, sandwich the fixation belt 100 .",
"The pressure roller 104 is rotatably supported by the lateral plates Fa and Fb, by the lengthwise end portions (shaft portions) 105 a and 105 b , with the placement of a pair of bearings (unshown) between the lengthwise end portions 105 a and 105 b and lateral plates Fa and Fb, respectively.",
"The belt backing member 108 , which is not rotational, is a member for pressing the fixation belt 100 upon the pressure roller 104 to form the fixation nip N. The belt backing member 108 has a fixation belt pressing surface 108 a , which is its downwardly facing surface and faces the pressure roller 104 .",
"The fixation belt pressing surface 108 a is pressed on the inward surface of the fixation belt 100 , forming thereby the fixation nip N. The shape of the fixation belt pressing surface 108 a will be described later in detail.",
"In this embodiment, the material for the belt backing member 108 is heat resistant resin such as LCP (liquid Crystal Polymer).",
"It may be a ceramic or metallic substance.",
"Each of the pressure bearing portions 102 a 3 and 102 b 3 of the above described flanges 102 a and 102 b is under 300 N of pressure generated by each of a pair of coil springs 116 a and 116 b , in the directions indicated by arrow marks Pa and Pb, which are perpendicular to the pressure application referential surfaces 117 a and 117 b .",
"Thus, the flanges 102 a and 102 b are kept pressed toward the pressure roller 104 by the resiliency of the coil springs 116 a and 116 b , causing the fixation belt pressing surface 108 a of the belt backing member 103 to press on the inward surface of the fixation belt 100 .",
"Thus, the outward surface of the fixation belt 100 is pressed upon the peripheral surface of the pressure roller 104 .",
"As the outward surface of the fixation belt 100 is pressed upon the peripheral surface of the pressure roller 104 , the rubber layer 106 of the pressure roller 104 is compressed, being thereby elastically deformed.",
"Consequently, the fixation nip N, which has a preset dimension (width) in terms of the rotational direction of the fixation belt 7 , is formed between the outward surface of the fixation belt 100 and the peripheral surface of the pressure roller 104 .",
"In this embodiment, the width (in terms of rotational direction of fixation belt 100 ) of the fixation nip N is 8.4 mm.",
"The fixing device B in this embodiment is provided with the friction reducing sheet 109 , which is placed between the fixation belt 100 and the belt backing member 108 to minimize the friction between the inward surface of the fixation belt 100 and the fixation belt pressing surface 108 a of the belt backing member 108 , in order to enable the fixation belt 100 to smoothly slide on the fixation belt pressing surface 108 a of the belt backing member 108 .",
"This friction reducing sheet 109 is large enough to cover the entirety of the fixation belt pressing surface 108 a in terms of the widthwise direction of the belt backing member 108 .",
"It is attached to the belt backing member 108 with the use of adhesive or the like to cover the entirety of the fixation belt pressing surface 108 a .",
"The material for the friction reducing sheet 109 is polyimide.",
"Next, referring to FIG. 4 , the laminar structure of the fixation belt 100 is described.",
"The fixation belt 100 has: a hollow, cylindrical, and metallic substrative layer, which generates heat by electromagnetic induction;",
"an elastic layer 113 formed on the peripheral surface of the sustrative layer 112 , with the placement of a primary layer (unshown) between the peripheral surface of the substrative layer and the elastic layer 113 p ;",
"and a parting layer 114 formed of fluorinated resin, on the outward surface of the elastic layer 113 .",
"As the material for the substrative layer 112 , nonmagnetic stainless steel, aluminum, or the like, may be used in place of magnetic metal such as iron, nickel, and stainless steel.",
"In this embodiment, nickel is used as the material for the substrative layer 112 .",
"Regarding the thickness of the substrative layer 112 , from the standpoint of temperature control and thermal response, it is desired to be as small as possible in thermal capacity, and therefore, as thin and possible.",
"However, from the standpoint of durability, it is desired as thick as possible.",
"Thus, the thickness of the substrative layer 112 in this embodiment was made to be roughly one to several hundred times the depth of penetration of electromagnetic wave, the frequency of which is in a range of 20 kHz-several hundreds kHz, that is, the range suitable for electromagnetic induction.",
"In this embodiment, the thickness of the substrative layer 112 was 75 μm.",
"As the material for the elastic layer 113 , a substance such as silicone rubber, fluorinated rubber, and fluoro-silicone rubber, that is excellent in heat resistance and thermal conductivity is used.",
"In this embodiment, solid silicone rubber which is 0.50-1.60 W/m·K in thermal conductivity was used.",
"The elastic layer 113 in this embodiment was 280 μm in thickness.",
"As the material for the parting layer 114 in this embodiment, PFA was used.",
"However, instead of PFA, fluorinated resin such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), or the like, may be used as the material for the parting layer 114 .",
"Further, the parting layer 114 may be a layer of GLS latex paint coated on the outward surface of the elastic layer 113 .",
"That is, the parting layer 114 may be a piece of tube stretched to cover the entirety of the outward surface of the elastic layer 113 , or a layer of the abovementioned paint coated on the outward surface of the elastic layer 113 .",
"A piece of tube, which is excellent in durability was used.",
"The thickness of the parting layer 114 was 30 μm.",
"In order to minimize the friction between the fixation belt 100 and friction reducing sheet 109 , the inward surface of the fixation belt 100 is coated with a slippery substance.",
"In this embodiment, the material of this friction reducing layer on the inward surface of the fixation belt 100 was polyimide, and the thickness of this layer was 30 μm.",
"A coil unit 110 is disposed on the opposite side of the fixation belt 100 from the pressure roller 104 .",
"It has: an excitation coil 111 (magnetic field generating means) as a heating energy source;",
"a magnetic core 112 ;",
"a holder 113 ;",
"etc.",
"The holder 113 is in the form of a long and narrow box, the lengthwise direction of which is parallel to the lengthwise direction of the fixation belt 100 .",
"It is disposed in parallel to the fixation belt 100 , with its lengthwise end portions held by the aforementioned lateral plates Fa and Fb, one for one ( FIG. 3( a )).",
"More concretely, the holder 113 is in the form of a shallow trough, which is semi-circular in cross-section, and the curvature of which matches the curvature of the outward surface of the fixation belt 100 .",
"It is disposed so that its concave side opposes the outward surface of the fixation belt 100 with the presence of a preset gap g between itself and fixation belt 100 .",
"The excitation coil 111 is shaped so that its curvature matches the curvature of the fixation belt 100 .",
"It is in the holder 113 , being positioned so that a preset distance is maintained between itself and the outward surface of the fixation belt 100 .",
"As the wire for the excitation coil 111 , litz wire made by bundling several tens to roughly 200 strands of electrically conductive fine wire, which are 0.1-0.3 mm in diameter, was used.",
"The fine wire is coated with electrically insulating substance.",
"That is, the excitation coil 111 was made by winding the litz wire around the magnetic core 112 several to several tens of times.",
"The excitation coil 111 is in connection to an excitation circuit 200 so that alternating electric current can be supplied to the excitation coil 111 from the excitation circuit 200 .",
"The magnetic core 112 is made of a ferromagnetic substance.",
"It is structured so that it embraces the excitation coil, with its center portion fitting in the center of the excitation coil 111 .",
"The magnetic core 111 plays the role of efficiently guiding the alternating magnetic flux generated by the excitation coil 111 , to the substrative layer 112 of the fixation belt 100 .",
"That is, the magnetic core 112 improves in efficiency the magnetic circuit made up of the excitation coil 111 and the substrative layer 112 of the fixation belt 100 .",
"The length of the excitation coil 111 , and the length of the magnetic core 112 , are greater than the length of the long edge of a largest sheet of paper conveyable through the fixing device B. (2-2) Driving and Temperature Control of Fixing Device B The control section C rotationally drives a motor ( FIG. 2 ) M as a driving force source, in response to a print command.",
"The rotation of the output shaft of the motor M is transmitted to a driving gear (unshown) attached to one of the lengthwise ends of the metallic core 105 , through a gear train (unshown).",
"Thus, the pressure roller 104 rotates at a preset peripheral velocity in the direction indicated by an arrow mark.",
"In this embodiment, the pressure roller 104 is rotated at a peripheral velocity of 321 mm/sec.",
"The rotation of this pressure roller 104 is transferred, as belt driving force, to the fixation belt 100 by the friction between the peripheral surface of the pressure roller 104 and the outward surface of the fixation belt 100 , in the fixation nip N. Thus, the fixation belt 100 is rotated by the rotation of the pressure roller 104 , remaining in contact with the friction reducing sheet 109 by its inward surface.",
"It is possible that while the fixation belt 100 is rotated, it will deviate in its lengthwise direction.",
"However, if the fixation belt 100 deviates in its lengthwise direction, one of its edges comes into contact with the base portion 102 a or 102 b of the corresponding flange 102 a or 102 b , respectively.",
"Therefore, the fixation belt 100 is prevented from deviating in its lengthwise direction.",
"Further, the control section C starts up the excitation circuit 200 in response to the print command.",
"The excitation circuit 200 causes alternating electric current to flow through the excitation coil 111 of the coil unit 110 .",
"Thus, the excitation coil 111 generates an alternating magnetic flux.",
"This alternating magnetic flux is guided by the magnetic core 112 to the fixation belt 100 , generating thereby eddy current in the outward surface layer of the fixation belt 100 .",
"Thus, Joule's heat is generated in the fixation belt 100 due to the presence of the intrinsic electrical resistance of the substrative layer 112 .",
"The temperature of the fixation belt 100 is detected by a temperature detecting member S, such as a thermistor, which is placed in the adjacencies of, or in contact with, the outward surface of the fixation belt 100 .",
"Then, the signals outputted by the temperature detecting member S are taken in by the control section C. Then, the control section C controls the excitation circuit 200 in response to the output signals from the temperature detecting member S, so that the temperature of the fixation belt 100 remains at a preset level (fixation temperature: target temperature).",
"While the motor M is rotationally driven, and the alternating electric current is flowed through the excitation coil 111 , a sheet P of recording medium, on which an unfixed toner image is present, is introduced into the fixation nip N, in such an attitude that the image bearing surface of the sheet P faces the fixation belt 100 .",
"Then, the sheet P is conveyed through the fixation nip N, remaining sandwiched between the outward surface of the fixation belt 100 and the peripheral surface of the pressure roller 104 .",
"While the sheet P is conveyed through the fixation nip N, the unfixed toner image on the sheet P is heated by the heat of the fixation belt 100 , while being subjected to the internal pressure of the fixation nip N. Thus, the unfixed toner image on the sheet P becomes fixed to the sheet P. Then the sheet P is conveyed out of the fixation nip N. Then, the sheet P is discharged from the fixing device B in such a manner that the toner image bearing surface of the sheet P separates from the outward surface of the fixation belt 100 .",
"(3) Shape of Fixation Belt Pressing Surface 108 a of Belt Backing Member 108 FIG. 5 is a schematic cross-sectional view of the fixation nip N, and its adjacencies, of the fixing device B in this embodiment.",
"It shows the structure of the fixation nip N and its adjacencies.",
"It should be noted here that in order to make it easier to recognize the shape of the fixation belt pressing surface 108 a of the belt backing member 108 , the belt guide 101 and friction reducing sheet 109 are not illustrated in FIG. 5 .",
"In this embodiment, the shape of the fixation belt pressing surface 108 a of the belt backing member 108 , in terms of its cross-sectional view, is such that the portion of the fixation belt pressing surface 108 a , which is in the upstream area of the fixation nip N, in terms of the recording medium conveyance direction, bulge in circular curvature (first curved surface) toward the pressure roller 104 , whereas the portion of the fixation belt pressing surface 108 a , which is the downstream area of the fixation nip N concaves in curvature (second curved surface).",
"More concretely, referring to FIG. 5 , in this embodiment, the portion of the fixation belt pressing surface 108 a , which bulges in circular curvature, was 7 mm in width, and the portion of the fixation belt pressing surface 108 a , which concaves in curvature was 3.3 mm in width.",
"Further, the portion of the fixation belt pressing surface 108 a , which bulges in circular curvature toward the pressure roller 104 in the upstream area of the fixation nip N was 6.1 mm in width.",
"Therefore, the rest of the fixation belt pressing surface 108 a , which is in the fixation nip N and concaves in curvature, was 2.3 mm (8.4 mm (nip width)-upstream portion (6.1 mm)) in width.",
"Here, “bulges in circular curvature”",
"means to protrude in curvature toward the pressure roller 104 , and “concaves in curvature”",
"means to recess toward the opposite surface of the belt backing member 108 from the fixation belt pressing surface 108 a. That is, in terms of the cross-sectional view of the belt backing member, the portion of the fixation belt pressing surface 108 a of the belt backing member 108 , which is in the upstream area Nu of the fixation nip N relative to the center Nc of the fixation nip N in terms of the recording medium conveyance direction, bulges in circular curvature toward the pressure roller 104 , whereas the portion of the fixation belt pressing surface 108 a of the belt backing member 108 , which is in the area between the downstream edge Nut of the upstream area Nu, and the downstream edge of the fixation nip N, in terms of the rotational direction of the fixation belt 100 , concaves in curvature away from the pressure roller 104 .",
"In the case of the fixing device B in this embodiment, the above described curvature in which the upstream portion of the fixation belt pressing surface 108 a bulges toward the pressure roller is equivalent to the curvature of a circle which is 15 mm in radius (which hereafter may be referred to as R 15 ).",
"As described above, the external diameter of the fixation belt 100 is 30 mm (R 15 ).",
"Thus, the relationship between the radius R 1 of the curvature in which the upstream portion of the fixation belt pressing surface 108 a bulges, and the radius R 2 is: R 1 =R 2 .",
"Therefore, when a given portion of the fixation belt 100 , is in the portion of the fixation nip N, which is between the entrance Nin of the fixation nip N to a point which is 6.1 mm downstream from the entrance Nin, the given portion of the fixation belt 100 is allowed to maintain its intrinsic curvature, and therefore, it smoothly moves, that is, without being stressed.",
"Thus, in the above described area of the fixation nip N, that is, the area from the nip entrance Nin to the point which is 6.1 mm downstream from the entrance Nin, the above described amount of “compression”",
"of the outward surface layer of the fixation belt 100 is zero.",
"In comparison, the curvature of the above-described concaved portion is equivalent to the curvature of a circle which is R 17 .",
"5 .",
"Therefore, the amount of compression of the portion of the fixation belt 100 , which is between the downstream edge Nut of the upstream portion area Nu in the fixation nip N, and the exit Nout of the fixation nip N, is greater than zero (amount of compression >0).",
"FIG. 6 shows the changes in the amount of compression of the outward surface layer of the fixation belt 100 , which occur in the fixation nip N. As will be evident from FIG. 6 , in the case of the fixing device B in this embodiment, which is structured as described above, the amount by which fixation belt 100 is compressed in the upstream area Nu of the fixation nip, relative to the center Nc of the fixation nip N, is no more than zero (amount of compression ≦0.",
"Therefore, it is unlikely that this area of the fixation nip N causes image defects.",
"The temperature of the toner, of which the unfixed toner is formed (toner on sheet P), exceeds the softening point (Tg) of toner while the toner is in the upstream area Nu in the fixation nip N relative to the center Nc, although it will be affected by the condition under which an image forming apparatus is used.",
"Therefore, if the parting layer 114 , which is the outward surface layer of the fixation belt 100 wrinkles in the upstream area Nu of the fixation nip N, it is likely for some of the toner particles on a sheet P of recording medium to be shifted in position.",
"Therefore, it is desired that the portion of the fixation belt pressing surface 108 a of the belt backing member 108 , which bulges in circular curvature toward the pressure roller 104 , extends downstream from the nip entrance Nin beyond the center Nc of the fixation nip N. The amount by which the fixation belt 100 is compressed in the downstream area Nd of the fixation nip N, which is 2.3 mm in width is positive in value.",
"However, in the downstream area Nd in the fixation nip N, the toner particles on the sheet P of recording medium will have melted further, becoming therefore better fixed to the sheet P, as described before.",
"Therefore, even if the parting layer 114 , that is, the outward surface layer of the fixation belt 100 , wrinkles, it hardly occurs that the toner particles on the sheet P are shifted in position enough for the area of the surface of the sheet P, which is under the toner particles, to become exposed.",
"Shaping the fixation belt backing member 108 so that its portion in the upstream area Nu of the fixation nip N bulges in circular curvature toward the pressure roller 104 , has the secondary effect, which is the increase in the internal pressure of the upstream area Nu in the fixation nip N. Making the portion of the fixation belt pressing surface 108 a , which corresponds in position to the upstream area Nu of the fixation nip N, bulge in circular curvature toward pressure roller 104 , increases the belt backing member 108 (fixation belt pressing surface 108 a ) in the depth of its intrusion into the pressure roller 104 .",
"It therefore increases the upstream area Nu of the fixation nip N in internal pressure, which in turns makes it easier for the toner to melt.",
"Thus, the toner becomes more adherent to the sheet P of recording medium (paper), and also, toner particles increase in the force of mutual adhesion.",
"Therefore, it becomes unlikely for the toner particles on the sheet P to be shifted in position.",
"That is, this secondary effect makes it even more unlikely for the image forming apparatus to output a defective image, the defect of which is attributable to the problem that the toner particles on a sheet of recording medium are made to shift in position by the wrinkling of the fixation belt.",
"From the standpoint of merely preventing the problem that the wrinkling of the fixation belt of an electrophotographic image forming apparatus makes the apparatus output a defective image, the entire portion of the fixation belt pressing surface 108 a of the belt backing member 108 , in the fixation nip N, may be made to bulge in circular curvature toward the pressure roller 104 , like in the upstream area Nu.",
"However, such a structural arrangement makes it difficult for a sheet P of recording medium (paper) to separate from the outward surface of the fixation belt 100 .",
"In this embodiment, therefore, the fixation belt pressing surface 108 a is shaped so that its portion in the upstream area Nu of the fixation nip N, which is necessary to prevent the image forming apparatus from outputting a defective image, the defects of which is attributable to the wrinkling of the outward surface layer of the fixation belt 100 , bulges toward the pressure roller 104 in the above described curvature, and its portion in the downstream area Nd in the fixation nip N concaves in the above described curvature to ensure a sheet of recording medium (paper) separates from the outward surface of the fixation belt 100 .",
"In order to ensure that a sheet of recording medium (paper) separates from the outward surface of the fixation belt 100 , the fixation belt pressing surface 108 a of the belt backing member 108 (fixation nip N) has to be shaped so that when the sheet comes out of the fixation nip N, the downstream portion of the sheet is directed away from the fixation belt 100 (toward pressure roller 104 ), and the fixation belt 100 is guided away from the pressure roller 104 .",
"Therefore, the inventors of the present invention built a fixing device structured so that the belt backing member 108 is displaced downward in terms of the belt movement direction (to position the rotational axis of the fixation belt 100 downstream relative to the rotational axis of the pressure roller 104 by a distance Wa in terms of the belt movement direction) to optimize the fixing device B in terms of the state of separation of a sheet of recording medium (paper) from the outward surface of the fixation belt 100 .",
"Then, the fixing device was used to study this structural arrangement.",
"The results of the study confirmed that in the case of a fixing device such as the fixing device B in this embodiment structured as described above, providing a distance of 1 mm between the exit Nout of the fixation nip N and the downstream edge 108 ae of the area of contact between the fixation belt pressing surface 108 a and fixation belt 100 makes a sheet of recording medium (paper) naturally separate from the outward surface of the fixation belt 100 .",
"FIG. 7 is an enlarged view, which was obtained with a microscope, of a part of a fixed solid monochromatic cyan image formed on a sheet of recording paper with the use of a full-color laser printer which employs the fixing device B in this embodiment.",
"It is obvious from the comparison between FIGS. 7 and 16 that the image in FIG. 7 does not show any sign of the image defect called “cracking.”",
"[Embodiment 2] Next, another embodiment of the present invention is described.",
"The fixing device B in this embodiment is also of the belt-based heating method.",
"However, this fixing device B employs a ceramic heater (heat generating member) as a heat source.",
"The fixing device B in this embodiment is virtually the same as the fixing device in the first embodiment, except that its heater 118 doubles as the belt backing member 108 in the first embodiment, and some of the structural components of this fixing device B are different in measurements or the like attributes.",
"(1) Fixing Device FIG. 8 is a schematic cross-sectional view of the fixing device B in this embodiment.",
"It shows the general structure of the device B. FIG. 9( a ) is a schematic side view of the fixing device B in this embodiment, as seen from the upstream side of the device in terms of the recording conveyance direction, and shows the general structure of the device B, and FIG. 9( b ) is a schematic vertical sectional view of the fixing device B shown in FIG. 9( a ), and shows the general structure of the device B. FIG. 10 is a schematic view of the ceramic heater 118 in this embodiment, as seen from the center of the fixation belt loop, and shows the general structure of the heater 118 .",
"(1-1) Overall Structure of Fixing Device B Referring to FIG. 8 , a referential code 100 stands for a fixation belt in this embodiment.",
"The substrative layer 112 of this fixation belt 100 is 34 μm in thickness.",
"Its material is SUS.",
"The outward surface of the substrative layer 112 is covered with an elastic layer 113 formed of silicone rubber.",
"In this embodiment, the thickness of this silicone rubber layer is 275 μm.",
"Further, the outward surface of the elastic layer 113 is covered with a parting layer 114 formed of PFA, which is 30 μm in thickness.",
"In this embodiment, the external diameter of the fixation belt 100 is 25 mm.",
"The heater 118 is attached to the bottom surface of the belt guide 110 .",
"It has a long and narrow substrate 118 b , which is formed in a preset shape, of a metallic substance such as aluminum, iron, copper, or the like.",
"The heater 118 has also an unshown insulating layer formed by hardening the heat resistant resin, such as polyimide, coated on the back surface, that is, the opposite surface of the substrate 118 b from the fixation nip N. Further, the heater 118 has a heat generating layer 118 c formed on the insulating layer, of electrically resistive substance, by screen-printing paste of Ag/Pd, RuO 2 , Ta 2 N, or the like on the insulating layer to a thickness of roughly 100 μm, and baking the printed layer.",
"One of the lengthwise ends of the heat generating layer 118 c is in electrical connection with the electrode 118 e 1 through an electrically conductive portion 118 d 1 .",
"As for the other lengthwise end of the heat generating layer 118 c , it is in electrical connection to the electrode 118 e 2 through the electrically conductive portion 118 d 2 .",
"Each of the electrodes 118 e 1 and 118 e 2 is in connection to a pair of electric power supply connectors (unshown), one for one, so that the electrical power is supplied to the heat generating layer 118 b from an electric power supply control circuit 201 through a pair of the power supply connectors.",
"The heater 118 is supported, along with the belt guide 101 , by the recessed portions 102 a 4 and 102 b 4 of the base portions 102 a 1 and 102 b 1 of the flange 102 a and 102 b , respectively.",
"Further, this heater 118 has a fixation belt pressing surface 118 a .",
"The fixing device B is structured so that this fixation belt pressing surface 118 a is pressed on the inward surface of the fixation belt 100 to form the fixation nip N. The shape of this fixation belt 118 a will be described later in detail.",
"The pressure bearing portions 102 a 3 and 102 b 3 of the flanges 102 a and 102 b are under 150 N of pressure applied to the pressure application referential surfaces 117 a and 117 b by a pair of coil springs 116 a and 116 b in the direction indicated by arrow marks Pa and Pb, respectively.",
"The flanges 102 a and 102 b are kept pressed toward the pressure roller 104 by the pressure generated by the pair of coil springs 116 a and 116 b .",
"Thus, the fixation belt pressing surface 118 a of the heater 118 presses on the inward surface of the fixation belt 100 , keeping thereby the outward surface of the fixation belt 100 in contact with the peripheral surface of the pressure roller 104 .",
"As the outward surface of the fixation belt 100 is pressed upon the peripheral surface of the pressure roller 104 , the rubber layer 106 of the pressure roller 104 is elastically compressed.",
"Consequently, the fixation nip N, which has a preset width, is formed between the outward surface of the fixation belt 100 and the peripheral surface of the pressure roller 104 .",
"In this embodiment, the width of the fixation nip N is 6.0 mm.",
"Like in the case of the first embodiment, the inward surface of the fixation belt 100 is covered with an unshown coated layer of a slippery substance to minimize the friction between the fixation belt 100 and the friction reducing sheet 109 .",
"This coated layer is formed of polyimide, and its thickness is no more than 10 μm.",
"In order to prevent the pressure roller 104 from robbing an excessive amount of heat from the fixation belt 100 , the pressure roller 104 is desired to be low in thermal capacity and thermal conductivity.",
"The pressure roller 104 is 20 mm in external diameter.",
"It is made up of a metallic core 105 , an elastic layer 106 (silicone rubber layer), and a parting layer 107 .",
"The metallic core is formed of SUS.",
"The elastic layer 106 is formed on the peripheral surface of the metallic core 105 , and is 3.5 mm in thickness.",
"The parting layer 107 is formed, as the outermost layer, on the outward surface of the elastic layer 106 .",
"It is formed of PFA, and is 65 μm in thickness.",
"(1-2) Driving and Temperature Control of Fixing Device B The control section C rotationally drives a motor ( FIG. 8 ) M as a driving force source, in response to a print command.",
"The rotation of the output shaft of the motor M is transmitted to a driving gear (unshown) attached to one of the lengthwise ends of the metallic core 105 , through a gear train (unshown).",
"Thus, the pressure roller 104 rotates at a preset peripheral velocity in the direction indicated by an arrow mark.",
"In this embodiment, the pressure roller 104 is rotated at a peripheral velocity of 200 mm/sec.",
"The rotation of this pressure roller 104 is transferred, as belt driving force, to the fixation belt 100 by the friction between the peripheral surface of the pressure roller 104 and the outward surface of the fixation belt 100 , in the fixation nip N. Thus, the fixation belt 100 is rotated by the rotation of the pressure roller 104 , remaining in contact with the friction reducing sheet 109 by its inward surface.",
"Further, the control section C drives a triac 201 in response to the print command.",
"As the triac 201 is driven, electric power is supplied to the heat generating layer 118 c from a commercial electric power source (unshown).",
"As the heat generating layer 108 c receives electric power, it generates heat.",
"Thus, the heater 118 quickly increases in temperature, and heats the fixation belt 100 from the inward side of the fixation belt loop.",
"The temperature of the fixation belt 100 is detected by a temperature detecting member S, such as a thermistor, which is placed in the adjacencies of, or in contact with, the outward surface of the fixation belt 100 .",
"Then, the signals outputted by the temperature detecting member S are taken in by the control section C. Then, the control section C decides the duty ratio for the voltage to be applied to the heat generating layer 118 c , and controls the triac 201 to keep the temperature of the heater 118 at a preset level (fixation temperature;",
"target temperature).",
"While the motor M is rotationally driven, and the heater 118 is being supplied with electric power, a sheet P of recording medium, on which an unfixed toner image is present, is introduced into the fixation nip N, in such an attitude that the image bearing surface of the sheet P faces the fixation belt 100 .",
"Then, the sheet P is conveyed through the fixation nip N, remaining sandwiched between the outward surface of the fixation belt 100 and the peripheral surface of the pressure roller 104 .",
"While the sheet P is conveyed through the fixation nip N, the unfixed toner image on the sheet P is heated by the heat of the fixation belt 100 , and subjected to the internal pressure of the fixation nip N. Thus, the unfixed toner image on the sheet P becomes fixed to the sheet P. Then, the sheet P is conveyed out of the fixation nip N. Then, the sheet P is discharged from the fixing device B in such a manner that the toner image bearing surface of the sheet P separates from the outward surface of the fixation belt 100 .",
"(2) Shape of Fixation Belt Pressing Surface 118 a of Heater 118 FIG. 11 is a schematic cross-sectional view of the fixation nip N, and its adjacencies, of the fixing device B in this embodiment, and shows the general structure of the fixation nip N and its adjacencies.",
"In order to make it easier to recognize the shape of the fixation belt pressing surface 118 a of the heater 118 , the belt guide 101 and friction reducing sheet 109 are not illustrated in FIG. 11 .",
"Referring to FIG. 11 , the nip forming surface 118 a is the same in basic shape as the counterpart in the first embodiment.",
"That is, in terms of the cross-sectional shape of the fixation belt pressing surface 118 a of the heater 118 , the heater 118 is shaped so that the portion of the fixation belt pressing surface 118 a of the heater 118 , which is in the upstream portion of the fixation nip N bulges in circular curvature toward the pressure roller 104 , whereas the portion of the fixation belt pressing surface 118 a , which is in downstream portion of the fixation nip N, concaves in curvature toward the heat generating layer 118 c. Concretely, referring to FIG. 11 , the portion of the fixation belt pressing surface 118 a , which bulges in circular curvature is 5.0 mm in width, and the portion of the fixation belt pressing surface 118 a , which concaves in curvature, is 2.4 mm in width.",
"Therefore, of the portion of the fixation belt pressing surface 118 a (fixation nip forming surface) in the fixation nip N which is 6.0 mm in width, the upstream portion which bulges in circular curvature is 4.0 mm in width, and the rest, that is, the downstream portion, which concaves in curvature, is 2.0 mm in width.",
"That is, in terms of the cross-section shape of the portion of the heater 118 in the fixation nip N, the fixation belt pressing surface 118 a of the heater 118 , which is in the upstream area Nu relative to the center Nc of the fixation nip N in terms of the recording medium conveyance direction, bulges in circular curvature toward the pressure roller 104 , whereas the fixation belt pressing surface 118 a of the heater 118 , which is in the downstream area Nd, which is the area between the downstream edge Nut of the upstream area Nu and the downstream edge of the fixation nip N, in terms of the rotational direction of the fixation belt 100 , concaves in curvature toward the heat generating layer 118 c .",
"In FIG. 11 , a referential code 118 ae stands for the most downstream edge of the area of contact between the fixation belt pressing surface 118 a and fixation belt 100 in terms of the rotational direction of the fixation belt 100 .",
"In the case of the fixing device B in this embodiment, the external diameter of the fixation belt 100 is 25 mm (R 12 .",
"5 ).",
"Therefore, the circular curvature in which the fixation belt pressing surface 118 a bulges in the upstream area Nu in the fixation nip N is made to be R 12 .",
"5 .",
"Here, the relationship between the radius R 1 of the circular curvature in which the fixation belt pressing surface 118 a bulges and the radius R 2 of the fixation belt 100 is: R 1 =R 2 .",
"Further, the curvature in which the fixation belt pressing surface 118 a concaves in the downstream area Nd was set also to R 12 .",
"5 to ensure that a sheet of recording paper satisfactorily separates from the outward surface of the fixation belt 100 as in the first embodiment.",
"Shown in FIG. 12 is the change in the amount of compression of the parting layer 114 , or the outward surface layer of the fixation belt 100 , which occurs in the fixation nip N. Because the fixing device B in this embodiment is structured as described above, the amount of the compression of the parting layer 114 , which occurs in the upstream area Nu of the fixation nip N relative to the center Nc of the fixation nip N is zero.",
"Therefore, the occurrence of the image defect is significantly suppressed.",
"Embodiment 3 Next, another embodiment of the present invention is described.",
"In the case of the fixing device B in the first embodiment, the circular curvature in which the fixation belt pressing surface 108 a of the belt backing member 108 is made to bulge toward the pressure roller 104 in the upstream area Nu of the fixation nip N is the same as the curvature of the fixation belt 100 .",
"However, the former may be different from the latter.",
"In this embodiment, therefore, the former is made different from the latter.",
"Otherwise, the fixing device B in this embodiment is the same in structure as the fixation device B in the first embodiment.",
"FIG. 13 is a schematic cross-sectional view of the fixation nip N, and its adjacencies, of the fixing device B in this embodiment.",
"It shows the general structure of the fixation nip N and its adjacencies.",
"Referring to FIG. 13 , in the case of the fixing device B in this embodiment, the radius of the fixation belt 100 is R 15 , and the circular curvature in which the fixation belt pressing surface 108 a of the belt backing member 108 is made to bulge in the fixation nip N toward the pressure roller 104 is R 12 in radius, whereas the circular curvature in which the fixation belt pressing surface 108 a is made to concave in the downstream area Nd of the fixation nip is R 17 .",
"5 which is the same as in the first embodiment.",
"Shown in FIG. 14 is the changes in the amount of compression of the outward surface layer of the fixation belt 100 , which occur in the fixation nip N of the fixing device B in this embodiment.",
"In the case of the fixing device B in this embodiment, the circular curvature in which the fixation belt pressing surface 108 a bulges in the upstream area Nu of the fixation nip N is R 12 in radius, which is smaller than the radius R 15 of the fixation belt 100 .",
"Thus, the relationship between the radiuses R 1 and R 2 is: R 1 <R 2 .",
"Based on Equation (1), therefore, the amount by which the parting layer 114 , which is the outward surface layer of the fixation belt 100 , is compressed is negative.",
"That is, the parting layer 114 is extended in the fixation nip N. Therefore, the fixing device B in this embodiment has the same effect as the effect which the fixing device B in the first embodiment has.",
"Further, making the circular curvature in which the fixation belt pressing surface 108 a of the fixing device B in the second embodiment bulges in the upstream area Nu of the fixation nip N smaller in radius than the fixation belt 100 has the same effect.",
"[Embodiment 4] Next, another embodiment of the present invention is described.",
"FIG. 15 is a schematic cross-sectional view of the fixation nip N, and its adjacencies, of the fixing device B in this embodiment.",
"It shows the general structure of the fixation nip N and its adjacencies.",
"FIG. 15( a ) represents a case in which the portion of the fixation belt pressing surface 108 a , which is in the downstream area Nd of the fixation nip N, is flat, and FIG. 15( b ) represents a case in which the portion of the fixation belt pressing surface 108 a , which is in the downstream area Nd of the fixation nip N, is a combination of a flat portion and a concave portion.",
"As is evident from the description of the first embodiment, all that is necessary to suppress the occurrence of the above described defective image is to make at least the portion of the fixation belt pressing surface 108 a of the belt backing member 108 , which is the upstream area Nu of the fixation nip N relative to the center Nc of the fixation nip N in terms of the rotational direction f the fixation belt 100 , bulge in circular curvature.",
"As for the shape of the portion of the fixation belt pressing surface 108 a , which is in the downstream area Nd of the fixation nip N, it does not need to be made to concave in circular curvature as it is in the first and second embodiments, as long as it can ensure that a sheet of recording paper separates from the outward surface of the fixation belt 100 .",
"Therefore, the portion of the fixation belt pressing surface 108 a , which is in the downstream area Nd of the fixation nip N, may be flat as shown in FIG. 15( a ), or a combination of a portion which is flat, and a portion which bulges in circular curvature as shown in FIG. 15( b ).",
"While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.",
"The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.",
"This application claims priority from Japanese Patent Application No. 003235/2013 filed Jan. 11, 2013 which is hereby incorporated by reference."
] |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent application Ser. No. 13/717,910, filed Dec. 18, 2012, which is a continuation of U.S. patent application Ser. No. 13/437,498, filed Apr. 2, 2012, which issued on Jan. 15, 2013 as U.S. Pat. No. 8,356,229, which is a continuation of U.S. patent application Ser. No. 13/227,214, filed Sep. 7, 2011, which issued on Apr. 3, 2012 as U.S. Pat. No. 8,151,164, which is a continuation of U.S. patent application Ser. No. 11/928,390, filed Oct.30, 2007, which issued on Sep. 27, 2011 as U.S. Pat. No. 8,028,217, which claims the benefit of U.S. Provisional Application Nos. 60/863,428 filed Oct. 30, 2006 and 60/863,473 filed Oct. 30, 2006, which are incorporated by reference as if fully set forth.
FIELD OF INVENTION
[0002] The present invention is related to wireless communication.
BACKGROUND
[0003] In third generation partnership project (3GPP) high speed downlink packet access (HSPDA), control information that is necessary for decoding high speed downlink shared channel (HS-DSCH) is transmitted via a high speed shared control channel (HS-SCCH). Multiple HS-SCCHs may be transmitted to a set of wireless transmit/receive units (WTRUs) associated with a particular cell. The HS-SCCH carries two (2) parts of data: part 1 data and part 2 data. The part 1 data includes channelization code set information, modulation scheme information, etc. The part 2 data includes transport block size information, hybrid automatic repeat request (HARQ) process information, redundancy and constellation version information, WTRU identity (ID), etc. An HS-SCCH frame includes three time slots. The part 1 data is transmitted in the first time slot, and the part 2 data is transmitted in the second and third time slots.
[0004] FIG. 1 shows conventional HS-SCCH encoding. For encoding the part 1 data, the channelization code set information X ccs and modulation scheme information X ms are multiplexed to generate a sequence of bits X 1 . Rate 1/3 convolutional coding is applied to the sequence of bits X 1 to generate a sequence of bits Z 1 . The sequence of bits Z 1 is punctured for rate matching to generate a sequence of bits R 1 . The rate matched bits R 1 are masked in a WTRU-specific way using the WTRU ID to produce a sequence of bits S 1 . Masking in this context means that each bit is conditionally flipped depending on the mask bit value. For the WTRU specific masking, intermediate code word bits are generated by encoding the WTRU ID using the rate 1/2 convolutional coding.
[0005] For encoding the part 2 data, the transport block size information X tbs , HARQ process information X hap , redundancy version information X rv , and new data indicator La are multiplexed to generate a sequence of bits X 2 . From the sequence of bits X 1 and X 2 , cyclic redundancy check (CRC) bits are calculated. The CRC bits are masked with the WTRU ID, (X ue ), and then appended to the sequence of bits X 2 to form a sequence of bits Y. Rate 1/3 convolutional coding is applied to the sequence of bits Y to generate a sequence of bits Z2. The sequence of bits Z 2 is punctured for rate matching to generate a sequence of bits R 2. The sequences of bits S1 and R2 are combined and mapped to the physical channel for transmission.
[0006] The performance of the detection of the part 1 data is influenced by the Hamming distance between the masks used for multiple HS-SCCHs. The conventional method produces a set of masks with a minimum distance of eight (8). When these minimum distance codes are used, the HS-SCCH detection performance is not optimal. In addition, with implementation of multiple-input multiple-output (MIMO) for HSDPA, more data need to be carried by the HS-SCCH. Therefore, it is necessary to make more room for transmission of data related to MIMO implementation in the HS-SCCH.
SUMMARY
[0007] A method and apparatus for encoding and decoding HS-SCCH data are disclosed. For part 1 data encoding, a mask may be generated using a WTRU ID and a generator matrix with a maximum minimum Hamming distance. For part 2 data encoding, CRC bits are generated based on part 1 data and part 2 data. The number of CRC bits may be less than the WTRU ID. The CRC bits and/or the part 2 data are masked with a mask. The mask may be a WTRU ID or a punctured WTRU ID of length equal to the CRC bits. The mask may be generated using the WTRU ID and a generator matrix with a maximum minimum Hamming distance. The masking may be performed after encoding or rate matching.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] A more detailed understanding of the invention may be had from the following description, given by way of example and to be understood in conjunction with the accompanying drawings wherein:
[0009] FIG. 1 shows conventional HS-SCCH encoding;
[0010] FIG. 2 is a block diagram of an example Node-B for encoding HS-SCCH data;
[0011] FIG. 3 is a block diagram of an example WTRU for decoding HS-SCCH data; and
[0012] FIG. 4 shows simulation results for the selection error probability of the part 1 data v. signal-to-noise ratio (SNR) comparing the performance of the two HS-SCCH masking methods (prior art and the present invention) where two HS-SCCH codes are transmitted with different mask distances dictated the corresponding methods.
DETAILED DESCRIPTION
[0013] When referred to hereafter, the terminology “WTRU” includes but is not limited to a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a computer, or any other type of user device capable of operating in a wireless environment. When referred to hereafter, the terminology “Node-B” includes but is not limited to a base station, a site controller, an access point (AP), or any other type of interfacing device capable of operating in a wireless environment.
[0014] FIG. 2 is a block diagram of an example Node-B 200 for encoding HS-SCCH data. The Node-B 200 comprises an encoder 201 , a rate matching unit 204 , a masking unit 206 , a multiplexer 210 , a CRC unit 212 , a masking unit 214 , an encoder 218 , a rate matching unit 220 , and a transceiver 224 . The HS-SCCH data comprises part 1 data and part 2 data. The part 1 data is sent to the encoder 202 . The encoder 202 performs channel coding on the part 1 data 201 . The channel coded part 1 data 203 is then punctured by the rate matching unit 204 for rate matching. The rate matched part 1 data 205 is then masked with a mask by the masking unit 206 . The mask may be generated based on the WTRU ID 208 .
[0015] Codes are usually selected for both their performance and for the simplicity of the decoders. Convolutional codes are a good example of codes that have both good performance and low decoder complexity. There is of course some tradeoff between performance and decoder complexity. However, the decoder complexity is not a factor when selecting a code to use for the masking because the corresponding decoder need not exist in the WTRU. All that is needed is the mask itself which can be created by the much simpler encoder.
[0016] The masking unit 206 generates the mask by block coding the WTRU ID 208 with a generator matrix which produces masks with a maximum minimum-Hamming-distance. The mask is generated by a vector-matrix product of the WTRU ID and the generator matrix. The resulting mask is a linear combination of the rows of the generator matrix. An example generator matrix for (40,16) code is given below. It should be noted that the generator matrix shown below is provided as an example, not as a limitation, and any other generator matrix may be used alternatively. In this example, the mask is the 40-bit mask, and the WTRU ID is 16-bits long. This example uses a block code with a specified generator matrix which produces masks with minimum distance of twelve (12). This provides much better performance when multiple HS-SCCH transmissions at the minimum distance are used.
[0000]
[1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0 0 1 0 0 1 1 1 0 0 1 0 0 1 1 1 0]
[0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 1 0 1 0 1 0 0 0 1 1 1 0 0 1 0 0 1]
[0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 1 0 1 0 1 0 0 0 1 1 1 0 0 1 0 1]
[0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 1 0 1 0 1 0 0 0 1 1 1 0 0 1 1]
[0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 1 1 1 0 1 0 1 1 1 0 0 1 1 0 1 0 1 1 0]
[0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 1 1 1 1 0 1 1 0 0 0 1 0 0 0 0 1 0 1]
[0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 1 1 1 1 0 1 1 0 0 0 1 0 0 0 0 1 1]
[0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 1 1 1 1 0 0 1 0 0 0 0 0 0 0 1 1 0 0 1 1 1 0]
[0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 1 0 1 0 0 1 0 0 0 1 1 0 1 1 0 1 0 0 0 1 0 0 1]
[0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 1 0 1 0 0 1 0 0 0 1 1 0 1 1 0 1 0 0 0 1 0 1]
[0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 1 0 1 0 0 1 0 0 0 1 1 0 1 1 0 1 0 0 0 1 1]
[0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 1 1 0]
[0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 1 1 1 0 1 1 0 1 1 1 0 1 1 1 1 0 0 0 1]
[0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 1 1 1 0 1 1 0 1 1 1 0 1 1 1 1 0 0 1]
[0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 1 1 1 0 1 1 0 1 1 1 0 1 1 1 1 0 1]
[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 1 1 1 0 1 1 0 1 1 1 0 1 1 1 1 1]
[0017] Conventionally, the mask is generated by encoding the WTRU ID 208 using the rate 1/2 convolutional coding. The minimum Hamming distance of the conventional masks is eight (8). The improved Hamming distance of the masks generated by the present invention results in a performance improvement of the part 1 HS-SCCH decoder at the WTRU. FIG. 4 shows simulation results for the selection error probability of the part 1 data v. SNR comparing the performance of the two HS-SCCH masking methods (prior art and the present invention) where two HS-SCCH codes are transmitted with different mask distances dictated the corresponding methods. FIG. 4 shows performance improvement when using the mask with the Hamming distance of twelve (12) compared to the mask with the Hamming distance of eight (8).
[0018] Referring again to FIG. 2 , the part 1 data 201 and the part 2 data 211 are sent to the CRC unit 212 to calculate CRC bits. The CRC bits are attached to the part 2 data 211 . The number of CRC bits may be less than the length of the WTRU ID so that more data, (e.g., data for MIMO), may be included as the part 2 data. The combined part 2 data and the CRC bits 213 are sent to the masking unit 214 . The masking unit 214 performs masking to the CRC bits or CRC bits plus some or all of the part 2 data with a mask, which will be explained in detail below. The masked part 2 data and CRC bits 217 are encoded by the encoder 218 . The encoded part 2 data and CRC bits 219 are punctured by the rate matching unit 220 . The rate matched part 2 data and CRC bits 221 and the rate matched part 1 data 209 are multiplexed by the multiplexer 210 and sent to the transceiver 224 for transmission.
[0019] In accordance with one embodiment, the masking unit 214 may generate a mask having a size equal to or smaller than the size of the CRC bits plus the part 2 data. A portion of the mask is extracted and applied to the CRC bits and the remaining portion of the mask is applied to all or part of the part 2 data. The mask may be generated using the WTRU ID 216 and a generator matrix as disclosed above with respect to part 1 data masking to maximize the minimum Hamming distance of the masks.
[0020] In accordance with another embodiment, the WTRU ID may be used as a mask. The length of the WTRU ID may be longer than the CRC bits. Therefore, a part of the WTRU ID is used to mask the CRC bits and the remaining of the WTRU ID is used to mask the part 2 data. In accordance with yet another embodiment, the WTRU ID is punctured to be the same length as the CRC bits and the punctured WTRU ID is used to mask the CRC bits.
[0021] In accordance with still another embodiment, the masking unit 214 may be moved between the encoder and the rate matching unit. The masking unit 214 generates a mask of length equal to the rate matched part 2 data and CRC bits 221 . The masking unit 214 then applies the mask to the encoded part 2 data and CRC bits 219 . Alternatively, the masking unit 214 may be moved between the rate matching unit 220 and the multiplexer 210 , and applies the mask to the rate matched part 2 data and CRC bits 221 . The mask may be 80-bits long. The mask may be generated using the WTRU ID 216 and a generator matrix as disclosed above with respect to part 1 data masking to maximize the minimum Hamming distance of the masks.
[0022] FIG. 3 is a block diagram of an example WTRU 300 for decoding HS-SCCH data. The WTRU 300 includes a transceiver 302 , a de-multiplexer 304 , a de-masking unit 306 , a de-rate matching unit 310 , a decoder 312 , a de-rate matching unit 314 , a decoder 316 , a de-masking unit 318 , and a CRC unit 322 . The transceiver 302 receives a HS-SCCH transmission 301 including a first part on a first time slot of an HS-SCCH frame corresponding to the part 1 data and a second part on the second and third time slots of the HS-SCCH frame corresponding to the part 2 data. The first part 305 a and the second part 305 b are de-multiplexed by the de-multiplexer 304 .
[0023] The first part 305 a is de-masked by the de-masking unit 306 . The de-masking unit 306 generates the same mask used at the Node-B in the same way using the WTRU ID 308 . The mask may be generated with the WTRU ID 308 and the generator matrix as disclosed above. The de-rate matching unit 310 reverts the puncturing performed at the Node-B on the de-masked first part 309 . The de-rate matched first part 311 is then decoded by the decoder 312 to output part 1 data 313 . The part 1 data is also sent to the CRC unit 322 .
[0024] The second part 305 b is de-rate matched by the de-rate matching unit 314 to revert the puncturing performed at the Node-B. The de-rate matched second part 315 is then decoded by the decoder 316 to output part 2 data (may or may not be masked at the NodeB) and masked CRC bits 317 . The masked CRC bits and optionally the masked part 2 data 317 are de-masked by the de-masking unit 318 . The de-masking unit 318 uses the same mask used at the Node-B for the de-masking. The mask may be the WTRU ID 320 , punctured WTRU ID, or a mask generated by using the WTRU ID 320 and a generator matrix. The de-masking unit 318 outputs de-masked part 2 data and CRC bits 321 to the CRC unit 322 . The CRC unit 322 then performs a CRC check with the part 1 data 313 , the part 2 data, and CRC bits.
[0025] The de-masking unit 318 may be moved between the decoder 316 and the de-rate matching unit 314 , or between the de-rate matching unit 314 and the de-multiplexer 304 depending on the masking scheme performed at the Node-B. In this case, the mask may be 80-bits long, and the mask may be generated using the WTRU ID 216 and a generator matrix as stated above to maximize the minimum Hamming distance of the masks.
[0026] Although the features and elements of the present invention are described in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements. The methods or flow charts provided may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium for execution by a general purpose computer or a processor. Examples of computer-readable storage mediums include a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs).
[0027] Suitable processors include, by way of example, a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and/or a state machine.
[0028] A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, user equipment (UE), terminal, base station, radio network controller (RNC), or any host computer. The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, a Bluetooth® module, a frequency modulated (FM) radio unit, a liquid crystal display (LCD) display unit, an organic light-emitting diode (OLED) display unit, a digital music player, a media player, a video game player module, an Internet browser, and/or any wireless local area network (WLAN) module. | A method and apparatus for encoding and decoding high speed shared control channel (HS-SCCH) data are disclosed. For part 1 data encoding, a mask may be generated using a wireless transmit/receive unit (WTRU) identity (ID) and a generator matrix with a maximum minimum Hamming distance. For part 2 data encoding, cyclic redundancy check (CRC) bits are generated based on part 1 data and part 2 data. The number of CRC bits is less than the WTRU ID. The CRC bits and/or the part 2 data are masked with a mask. The mask may be a WTRU ID or a punctured WTRU ID of length equal to the CRC bits. The mask may be generated using the WTRU ID and a generator matrix with a maximum minimum Hamming distance. The masking may be performed after encoding or rate matching. | Concisely explain the essential features and purpose of the invention. | [
"CROSS REFERENCE TO RELATED APPLICATION [0001] This application is a continuation of U.S. patent application Ser.",
"No. 13/717,910, filed Dec. 18, 2012, which is a continuation of U.S. patent application Ser.",
"No. 13/437,498, filed Apr. 2, 2012, which issued on Jan. 15, 2013 as U.S. Pat. No. 8,356,229, which is a continuation of U.S. patent application Ser.",
"No. 13/227,214, filed Sep. 7, 2011, which issued on Apr. 3, 2012 as U.S. Pat. No. 8,151,164, which is a continuation of U.S. patent application Ser.",
"No. 11/928,390, filed Oct.30, 2007, which issued on Sep. 27, 2011 as U.S. Pat. No. 8,028,217, which claims the benefit of U.S. Provisional Application Nos. 60/863,428 filed Oct. 30, 2006 and 60/863,473 filed Oct. 30, 2006, which are incorporated by reference as if fully set forth.",
"FIELD OF INVENTION [0002] The present invention is related to wireless communication.",
"BACKGROUND [0003] In third generation partnership project (3GPP) high speed downlink packet access (HSPDA), control information that is necessary for decoding high speed downlink shared channel (HS-DSCH) is transmitted via a high speed shared control channel (HS-SCCH).",
"Multiple HS-SCCHs may be transmitted to a set of wireless transmit/receive units (WTRUs) associated with a particular cell.",
"The HS-SCCH carries two (2) parts of data: part 1 data and part 2 data.",
"The part 1 data includes channelization code set information, modulation scheme information, etc.",
"The part 2 data includes transport block size information, hybrid automatic repeat request (HARQ) process information, redundancy and constellation version information, WTRU identity (ID), etc.",
"An HS-SCCH frame includes three time slots.",
"The part 1 data is transmitted in the first time slot, and the part 2 data is transmitted in the second and third time slots.",
"[0004] FIG. 1 shows conventional HS-SCCH encoding.",
"For encoding the part 1 data, the channelization code set information X ccs and modulation scheme information X ms are multiplexed to generate a sequence of bits X 1 .",
"Rate 1/3 convolutional coding is applied to the sequence of bits X 1 to generate a sequence of bits Z 1 .",
"The sequence of bits Z 1 is punctured for rate matching to generate a sequence of bits R 1 .",
"The rate matched bits R 1 are masked in a WTRU-specific way using the WTRU ID to produce a sequence of bits S 1 .",
"Masking in this context means that each bit is conditionally flipped depending on the mask bit value.",
"For the WTRU specific masking, intermediate code word bits are generated by encoding the WTRU ID using the rate 1/2 convolutional coding.",
"[0005] For encoding the part 2 data, the transport block size information X tbs , HARQ process information X hap , redundancy version information X rv , and new data indicator La are multiplexed to generate a sequence of bits X 2 .",
"From the sequence of bits X 1 and X 2 , cyclic redundancy check (CRC) bits are calculated.",
"The CRC bits are masked with the WTRU ID, (X ue ), and then appended to the sequence of bits X 2 to form a sequence of bits Y. Rate 1/3 convolutional coding is applied to the sequence of bits Y to generate a sequence of bits Z2.",
"The sequence of bits Z 2 is punctured for rate matching to generate a sequence of bits R 2.",
"The sequences of bits S1 and R2 are combined and mapped to the physical channel for transmission.",
"[0006] The performance of the detection of the part 1 data is influenced by the Hamming distance between the masks used for multiple HS-SCCHs.",
"The conventional method produces a set of masks with a minimum distance of eight (8).",
"When these minimum distance codes are used, the HS-SCCH detection performance is not optimal.",
"In addition, with implementation of multiple-input multiple-output (MIMO) for HSDPA, more data need to be carried by the HS-SCCH.",
"Therefore, it is necessary to make more room for transmission of data related to MIMO implementation in the HS-SCCH.",
"SUMMARY [0007] A method and apparatus for encoding and decoding HS-SCCH data are disclosed.",
"For part 1 data encoding, a mask may be generated using a WTRU ID and a generator matrix with a maximum minimum Hamming distance.",
"For part 2 data encoding, CRC bits are generated based on part 1 data and part 2 data.",
"The number of CRC bits may be less than the WTRU ID.",
"The CRC bits and/or the part 2 data are masked with a mask.",
"The mask may be a WTRU ID or a punctured WTRU ID of length equal to the CRC bits.",
"The mask may be generated using the WTRU ID and a generator matrix with a maximum minimum Hamming distance.",
"The masking may be performed after encoding or rate matching.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0008] A more detailed understanding of the invention may be had from the following description, given by way of example and to be understood in conjunction with the accompanying drawings wherein: [0009] FIG. 1 shows conventional HS-SCCH encoding;",
"[0010] FIG. 2 is a block diagram of an example Node-B for encoding HS-SCCH data;",
"[0011] FIG. 3 is a block diagram of an example WTRU for decoding HS-SCCH data;",
"and [0012] FIG. 4 shows simulation results for the selection error probability of the part 1 data v. signal-to-noise ratio (SNR) comparing the performance of the two HS-SCCH masking methods (prior art and the present invention) where two HS-SCCH codes are transmitted with different mask distances dictated the corresponding methods.",
"DETAILED DESCRIPTION [0013] When referred to hereafter, the terminology “WTRU”",
"includes but is not limited to a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a computer, or any other type of user device capable of operating in a wireless environment.",
"When referred to hereafter, the terminology “Node-B”",
"includes but is not limited to a base station, a site controller, an access point (AP), or any other type of interfacing device capable of operating in a wireless environment.",
"[0014] FIG. 2 is a block diagram of an example Node-B 200 for encoding HS-SCCH data.",
"The Node-B 200 comprises an encoder 201 , a rate matching unit 204 , a masking unit 206 , a multiplexer 210 , a CRC unit 212 , a masking unit 214 , an encoder 218 , a rate matching unit 220 , and a transceiver 224 .",
"The HS-SCCH data comprises part 1 data and part 2 data.",
"The part 1 data is sent to the encoder 202 .",
"The encoder 202 performs channel coding on the part 1 data 201 .",
"The channel coded part 1 data 203 is then punctured by the rate matching unit 204 for rate matching.",
"The rate matched part 1 data 205 is then masked with a mask by the masking unit 206 .",
"The mask may be generated based on the WTRU ID 208 .",
"[0015] Codes are usually selected for both their performance and for the simplicity of the decoders.",
"Convolutional codes are a good example of codes that have both good performance and low decoder complexity.",
"There is of course some tradeoff between performance and decoder complexity.",
"However, the decoder complexity is not a factor when selecting a code to use for the masking because the corresponding decoder need not exist in the WTRU.",
"All that is needed is the mask itself which can be created by the much simpler encoder.",
"[0016] The masking unit 206 generates the mask by block coding the WTRU ID 208 with a generator matrix which produces masks with a maximum minimum-Hamming-distance.",
"The mask is generated by a vector-matrix product of the WTRU ID and the generator matrix.",
"The resulting mask is a linear combination of the rows of the generator matrix.",
"An example generator matrix for (40,16) code is given below.",
"It should be noted that the generator matrix shown below is provided as an example, not as a limitation, and any other generator matrix may be used alternatively.",
"In this example, the mask is the 40-bit mask, and the WTRU ID is 16-bits long.",
"This example uses a block code with a specified generator matrix which produces masks with minimum distance of twelve (12).",
"This provides much better performance when multiple HS-SCCH transmissions at the minimum distance are used.",
"[0000] [1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0 0 1 0 0 1 1 1 0 0 1 0 0 1 1 1 0] [0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 1 0 1 0 1 0 0 0 1 1 1 0 0 1 0 0 1] [0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 1 0 1 0 1 0 0 0 1 1 1 0 0 1 0 1] [0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 1 0 1 0 1 0 0 0 1 1 1 0 0 1 1] [0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 1 1 1 0 1 0 1 1 1 0 0 1 1 0 1 0 1 1 0] [0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 1 1 1 1 0 1 1 0 0 0 1 0 0 0 0 1 0 1] [0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 1 1 1 1 0 1 1 0 0 0 1 0 0 0 0 1 1] [0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 1 1 1 1 0 0 1 0 0 0 0 0 0 0 1 1 0 0 1 1 1 0] [0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 1 0 1 0 0 1 0 0 0 1 1 0 1 1 0 1 0 0 0 1 0 0 1] [0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 1 0 1 0 0 1 0 0 0 1 1 0 1 1 0 1 0 0 0 1 0 1] [0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 1 0 1 0 0 1 0 0 0 1 1 0 1 1 0 1 0 0 0 1 1] [0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 1 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 1 1 0] [0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 1 1 1 0 1 1 0 1 1 1 0 1 1 1 1 0 0 0 1] [0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 1 1 1 0 1 1 0 1 1 1 0 1 1 1 1 0 0 1] [0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 1 1 1 0 1 1 0 1 1 1 0 1 1 1 1 0 1] [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 1 1 1 0 1 1 0 1 1 1 0 1 1 1 1 1] [0017] Conventionally, the mask is generated by encoding the WTRU ID 208 using the rate 1/2 convolutional coding.",
"The minimum Hamming distance of the conventional masks is eight (8).",
"The improved Hamming distance of the masks generated by the present invention results in a performance improvement of the part 1 HS-SCCH decoder at the WTRU.",
"FIG. 4 shows simulation results for the selection error probability of the part 1 data v. SNR comparing the performance of the two HS-SCCH masking methods (prior art and the present invention) where two HS-SCCH codes are transmitted with different mask distances dictated the corresponding methods.",
"FIG. 4 shows performance improvement when using the mask with the Hamming distance of twelve (12) compared to the mask with the Hamming distance of eight (8).",
"[0018] Referring again to FIG. 2 , the part 1 data 201 and the part 2 data 211 are sent to the CRC unit 212 to calculate CRC bits.",
"The CRC bits are attached to the part 2 data 211 .",
"The number of CRC bits may be less than the length of the WTRU ID so that more data, (e.g., data for MIMO), may be included as the part 2 data.",
"The combined part 2 data and the CRC bits 213 are sent to the masking unit 214 .",
"The masking unit 214 performs masking to the CRC bits or CRC bits plus some or all of the part 2 data with a mask, which will be explained in detail below.",
"The masked part 2 data and CRC bits 217 are encoded by the encoder 218 .",
"The encoded part 2 data and CRC bits 219 are punctured by the rate matching unit 220 .",
"The rate matched part 2 data and CRC bits 221 and the rate matched part 1 data 209 are multiplexed by the multiplexer 210 and sent to the transceiver 224 for transmission.",
"[0019] In accordance with one embodiment, the masking unit 214 may generate a mask having a size equal to or smaller than the size of the CRC bits plus the part 2 data.",
"A portion of the mask is extracted and applied to the CRC bits and the remaining portion of the mask is applied to all or part of the part 2 data.",
"The mask may be generated using the WTRU ID 216 and a generator matrix as disclosed above with respect to part 1 data masking to maximize the minimum Hamming distance of the masks.",
"[0020] In accordance with another embodiment, the WTRU ID may be used as a mask.",
"The length of the WTRU ID may be longer than the CRC bits.",
"Therefore, a part of the WTRU ID is used to mask the CRC bits and the remaining of the WTRU ID is used to mask the part 2 data.",
"In accordance with yet another embodiment, the WTRU ID is punctured to be the same length as the CRC bits and the punctured WTRU ID is used to mask the CRC bits.",
"[0021] In accordance with still another embodiment, the masking unit 214 may be moved between the encoder and the rate matching unit.",
"The masking unit 214 generates a mask of length equal to the rate matched part 2 data and CRC bits 221 .",
"The masking unit 214 then applies the mask to the encoded part 2 data and CRC bits 219 .",
"Alternatively, the masking unit 214 may be moved between the rate matching unit 220 and the multiplexer 210 , and applies the mask to the rate matched part 2 data and CRC bits 221 .",
"The mask may be 80-bits long.",
"The mask may be generated using the WTRU ID 216 and a generator matrix as disclosed above with respect to part 1 data masking to maximize the minimum Hamming distance of the masks.",
"[0022] FIG. 3 is a block diagram of an example WTRU 300 for decoding HS-SCCH data.",
"The WTRU 300 includes a transceiver 302 , a de-multiplexer 304 , a de-masking unit 306 , a de-rate matching unit 310 , a decoder 312 , a de-rate matching unit 314 , a decoder 316 , a de-masking unit 318 , and a CRC unit 322 .",
"The transceiver 302 receives a HS-SCCH transmission 301 including a first part on a first time slot of an HS-SCCH frame corresponding to the part 1 data and a second part on the second and third time slots of the HS-SCCH frame corresponding to the part 2 data.",
"The first part 305 a and the second part 305 b are de-multiplexed by the de-multiplexer 304 .",
"[0023] The first part 305 a is de-masked by the de-masking unit 306 .",
"The de-masking unit 306 generates the same mask used at the Node-B in the same way using the WTRU ID 308 .",
"The mask may be generated with the WTRU ID 308 and the generator matrix as disclosed above.",
"The de-rate matching unit 310 reverts the puncturing performed at the Node-B on the de-masked first part 309 .",
"The de-rate matched first part 311 is then decoded by the decoder 312 to output part 1 data 313 .",
"The part 1 data is also sent to the CRC unit 322 .",
"[0024] The second part 305 b is de-rate matched by the de-rate matching unit 314 to revert the puncturing performed at the Node-B.",
"The de-rate matched second part 315 is then decoded by the decoder 316 to output part 2 data (may or may not be masked at the NodeB) and masked CRC bits 317 .",
"The masked CRC bits and optionally the masked part 2 data 317 are de-masked by the de-masking unit 318 .",
"The de-masking unit 318 uses the same mask used at the Node-B for the de-masking.",
"The mask may be the WTRU ID 320 , punctured WTRU ID, or a mask generated by using the WTRU ID 320 and a generator matrix.",
"The de-masking unit 318 outputs de-masked part 2 data and CRC bits 321 to the CRC unit 322 .",
"The CRC unit 322 then performs a CRC check with the part 1 data 313 , the part 2 data, and CRC bits.",
"[0025] The de-masking unit 318 may be moved between the decoder 316 and the de-rate matching unit 314 , or between the de-rate matching unit 314 and the de-multiplexer 304 depending on the masking scheme performed at the Node-B.",
"In this case, the mask may be 80-bits long, and the mask may be generated using the WTRU ID 216 and a generator matrix as stated above to maximize the minimum Hamming distance of the masks.",
"[0026] Although the features and elements of the present invention are described in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements.",
"The methods or flow charts provided may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium for execution by a general purpose computer or a processor.",
"Examples of computer-readable storage mediums include a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs).",
"[0027] Suitable processors include, by way of example, a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and/or a state machine.",
"[0028] A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, user equipment (UE), terminal, base station, radio network controller (RNC), or any host computer.",
"The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, a Bluetooth® module, a frequency modulated (FM) radio unit, a liquid crystal display (LCD) display unit, an organic light-emitting diode (OLED) display unit, a digital music player, a media player, a video game player module, an Internet browser, and/or any wireless local area network (WLAN) module."
] |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a bubble jet type ink-jet printhead. More particularly, the present invention relates to a high-density ink-jet printhead in which a plurality of nozzles, through which ink is ejected, are arrayed on an ink supply manifold in a plurality of rows, thereby increasing the number of nozzles per unit area.
[0003] 2. Description of the Related Art
[0004] In general, ink-jet printheads are apparatuses that eject a fine droplet of printer ink on a desired position of a paper to print an image containing one or more predetermined colors. To eject ink onto the paper, an ink-jet printer generally adopts an electro-thermal transducer method that ejects ink onto the paper by generating a bubble in ink using a heat source (this method is called a bubble jet type), or an electromechanical transducer method that ejects ink onto the paper using a change in the volume of ink due to the deformation of a piezoelectric body.
[0005] In a bubble-jet type ink ejection mechanism, as mentioned above, when power is applied to a heater including a resistance heating element, ink adjacent to the heater is rapidly heated to about 300° C. Heating the ink generates bubbles, which grow and swell, and thus apply pressure in the ink chamber filled with the ink. As a result, ink adjacent to a nozzle is ejected from the ink chamber through the nozzle.
[0006] There are multiple factors and parameters to consider in making an ink-jet printhead having an ink ejecting unit in a bubble-jet mode. First, it should be simple to manufacture, have a low manufacturing cost, and be capable of being mass-produced. Second, in order to produce high quality color images, the formation of undesirable satellite ink droplets that usually accompany an ejected main ink droplet must be avoided during the printing process. Third, cross-talk between adjacent nozzles, from which ink is not ejected, must be avoided, when ink is ejected from one nozzle, or when an ink chamber is refilled with ink after ink is ejected. For this purpose, ink back flow, i.e., when ink flows in a direction opposite to the direction in which ink is ejected, should be prevented. Fourth, for high-speed printing, the refilling period after ink is ejected should be as short a period of time as possible to increase the printing speed. That is, the driving frequency of the printhead should be high.
[0007] The above requirements, however, tend to conflict with one another. Furthermore, the performance of an ink-jet printhead is closely related to and affected by the structure and design, e.g., the relative sizes of ink chamber, ink passage, and heater, etc., as well as by the formation and expansion shape of the bubbles.
[0008] [0008]FIG. 1A illustrates an exploded perspective view of a structure of an ink ejector of a conventional bubble jet type ink-jet printhead according to the prior art. FIG. 1B illustrates a cross-sectional view for explaining a process of ejecting an ink droplet from a conventional bubble jet type ink-jet printhead. FIG. 1C illustrates a plan view of the arrangement of a plurality of nozzles in the conventional ink-jet printhead of FIG. 1A.
[0009] A conventional bubble jet type ink-jet printhead shown in FIGS. 1A through 1C includes a substrate 10 , barrier walls 38 that are formed on the substrate 10 and that form ink chambers 26 , which are filled with ink 49 , heaters 12 formed in the ink chambers 26 , and a nozzle plate 18 having nozzles 16 from which an ink droplet 49 ′ is ejected. The ink 49 is supplied to the ink chambers 26 via ink channels 24 from ink supply manifolds 14 in flow communication with an ink storage unit (not shown). As a result, the nozzles 16 , which are in flow communication with the ink chambers 26 , are also filled with the ink 49 due to capillary action. In the above ink-jet printhead, a plurality of heaters 12 and a plurality of ink chambers 26 are formed to correspond to the plurality of nozzles 16 , and are arranged in a row, adjacent to each of the ink supply manifolds 14 .
[0010] In operation of the above ink-jet printhead, the heaters 12 are supplied with current and heated to form bubbles 48 in the ink 49 filled in the ink chambers 26 . Then, the bubbles 48 expand and put pressure on the ink 49 filled in the ink chambers 26 , thereby ejecting an ink droplet 49 ′ to the outside via the nozzles 16 . Then, the ink 49 flows through the ink channels 24 to fill the ink chambers 26 .
[0011] A process of manufacturing a conventional printhead having the above structure, however, is complicated because the nozzle plate 18 and the substrate 10 are individually made and then bonded together. In particular, the nozzle plate 18 may be misaligned with respect to the substrate 10 during manufacture.
[0012] Additionally, as previously mentioned, the plurality of nozzles 16 , heaters 12 and ink chambers 26 are arranged on each manifold 14 in a row, but may be arranged at both sides of each manifold 14 in a row. With such a structure, however, there is a limitation in increasing the number of nozzles per unit area, i.e., the density of a nozzle. Accordingly, it is difficult to realize a high-density ink-jet printhead that prints quickly and has high resolution.
SUMMARY OF THE INVENTION
[0013] In an effort to solve the above problems, it is a feature of an embodiment of the present invention to provide a high-density ink-jet printhead in which hemispherical ink chambers are formed that satisfy the above conditions, and a plurality of nozzles are arranged on each ink supply manifold in a plurality of rows, thereby increasing the density of nozzles.
[0014] To provide the above feature, there is provided an ink-jet printhead including a substrate; a plurality of ink chambers formed in a hemispherical shape at a surface of the substrate and filled with ink; a manifold formed at a rear surface of the substrate, the manifold for supplying ink to the plurality of ink chambers; a plurality of ink channels each formed at a bottom of each of the plurality of ink chambers to be in flow communication with the manifold; a nozzle plate monolithically formed with the substrate; a plurality of nozzles formed on the nozzle plate, each formed to correspond to a center of each of the plurality of ink chambers; a plurality of heaters formed on the nozzle plate, each of the plurality of heaters having a ring shape and encircling a corresponding one of the plurality of nozzles; and a plurality of electrodes positioned on the nozzle plate and electrically connected to the plurality of heaters, the plurality of electrodes applying current to the heaters.
[0015] In an embodiment of the present invention, the plurality of nozzles are arrayed on the manifold in at least three rows. In a preferred embodiment of the present invention, the plurality of nozzles are arrayed on the manifold in five rows.
[0016] Preferably, the substrate is a silicon wafer and the nozzle plate is a silicon oxide layer formed by oxidizing a surface of the silicon wafer.
[0017] Preferably, each of the plurality of nozzles may have a nozzle guide extending in the depth direction of the ink chamber, at each edge of the plurality of nozzles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above features and advantages of the present invention will become readily apparent to those of ordinary skill in the art by describing in detail preferred embodiments thereof with reference to the attached drawings in which:
[0019] [0019]FIG. 1A illustrates an exploded perspective view of an ink ejector of a conventional bubble jet type ink-jet printhead;
[0020] [0020]FIG. 1B illustrates a cross-sectional view for explaining a process of ejecting an ink droplet from the ink-jet printhead of FIG. 1;
[0021] [0021]FIG. 1C illustrates a plan view of the conventional ink-jet printhead of FIG. 1A showing an arrangement of a plurality of nozzles;
[0022] [0022]FIG. 2 illustrates a plan view of an ink-jet printhead according to a preferred embodiment of the present invention;
[0023] [0023]FIG. 3 illustrates a cross-sectional view of the ink-jet printhead of FIG. 2, taken along line A-A′;
[0024] [0024]FIG. 4 illustrates a plan view of a unit ink ejector of the ink-jet printhead of FIG. 2;
[0025] [0025]FIG. 5 illustrates a cross-sectional view of the unit ink ejector of FIG. 4, taken along line B-B′; and
[0026] [0026]FIGS. 6A and 6B illustrate cross-sectional views of the mechanism of ejecting ink from an ink ejector having the structure shown in FIG. 5.
DETAILED DESCRIPTION OF THE INVENTION
[0027] Korean Patent Application No. 2001-66747, filed Oct. 29, 2001, and entitled: “High-Density Ink-jet Printhead having Multi-Arrayed Structure,” is incorporated by reference herein in its entirety.
[0028] Hereinafter, the present invention will be described in detail by describing a preferred embodiment of the present invention with reference to the accompanying drawings. Like reference numerals refer to like elements throughout the drawings. In the drawings, the shape and thickness of an element may be exaggerated for clarity and convenience. Further, it will be understood that when a layer is referred to as being on another layer or “on” a substrate, it may be directly on the other layer or on the substrate, or intervening layers may also be present.
[0029] [0029]FIG. 2 illustrates a plan view of an ink-jet printhead according to a preferred embodiment of the present invention. FIG. 3 illustrates a cross-sectional view of the ink-jet printhead of FIG. 2, taken along line A-A′.
[0030] Referring to FIGS. 2 and 3, in the ink-jet printhead according to a preferred embodiment of the present invention, five rows of ink ejectors 100 are arranged in a zigzag pattern on an ink supply manifold 112 , which is illustrated by dotted lines. Bonding pads 102 that are connected to each ink ejector 100 and are to be bonded with wires are positioned at both sides of each ink ejector 100 . Additionally, the manifold 112 is in flow communication with an ink storage unit (not shown) filled with ink.
[0031] The manifold 112 is formed at a rear surface of a substrate 110 , and a nozzle plate 120 having a plurality of nozzles 122 is formed on an opposing surface of the substrate 110 . Each one of a plurality of heaters 130 encircles a corresponding one of the plurality of nozzles 122 , which are formed on the nozzle plate 120 . Also, hemispherical ink chambers 114 , each one corresponding to one of the plurality of nozzles 122 , are formed on the substrate 110 . A plurality of ink channels 116 are formed to pass through a bottom of each ink chamber 114 , which are in flow communication with the manifold 112 .
[0032] The plurality of nozzles 122 are arrayed to be positioned on one manifold 112 in at least three rows, and preferably in five rows, as shown in FIG. 3. Further, the plurality of nozzles 122 may be freely arranged according to a printing algorithm for realizing an image. Since the plurality of nozzles 122 have a two-dimensional multi-array structure, it is possible to increase the number of nozzles per unit area, thereby enhancing the speed of printing and realizing a high-density ink-jet printhead having high resolution.
[0033] [0033]FIG. 4 illustrates a plan view of a unit ink ejector 100 of FIG. 2. FIG. 5 illustrates a cross-sectional view of the vertical structure of the unit ink ejector 100 of FIG. 4, taken along line B-B′. Referring to FIGS. 4 and 5, an ink chamber 114 , which is filled with ink, is formed on a substrate 110 of the ink ejector 100 , and a manifold 112 , which supplies ink to the ink chamber 114 , is formed at a rear surface of the substrate 110 . In addition, a manifold 112 and an ink channel 116 , which connects the ink chamber 114 and the manifold 112 , are formed at a center of a bottom of the ink chamber 114 . Preferably, the ink chamber 114 is hemispherical shaped.
[0034] Also preferably, the substrate 110 is formed of a silicon material that is used in fabricating an integrated circuit. For instance, the substrate 110 may be a silicon substrate of a crystal orientation of (100) and a thickness of about 500 μm. Use of a silicon wafer as the substrate 110 facilitates mass-production of the ink ejectors 100 . The ink chamber 114 may be formed by isotropically etching the surface of the substrate 110 that is exposed via the plurality of nozzles 122 , which are formed on a nozzle plate. Formation of the plurality of nozzles 122 will be explained later. The manifold 112 is formed by anisotropically etching the rear surface of the substrate 110 or by etching the rear surface of the substrate 110 to have a predetermined inclination. Here, the ink chamber 114 is formed in a hemispherical shape having a depth and a radius of about 20 μm. Alternatively, the ink chamber 114 may be formed by anisotropically etching the substrate 110 to a predetermined depth and then, isotropically etching the etched substrate 110 . The ink channel 116 may be formed by anistropically etching a center of a bottom of the ink chamber 114 via the nozzle 122 . The diameter of the ink channel 116 is the same as or slightly smaller than that of the nozzle 122 , thereby preventing ejected ink from flowing back into the ink channel 116 . The diameter of the ink channel 116 affects the speed of refilling ink after the ejecting of the ink, and thus must be precisely controlled.
[0035] At a surface of the substrate 110 , a nozzle plate 120 having the plurality of nozzles 122 is formed to provide the upper walls of the ink chamber 114 . When the substrate 110 is formed of silicon, the nozzle plate 120 may be a silicon oxide layer that is formed by oxidizing the silicon substrate 110 . More particularly, a silicon wafer is wet or dry-oxidized in an oxidation furnace, thereby forming an oxide layer on the silicon substrate 110 , and thus the nozzle plate 120 .
[0036] On the nozzle plate 120 , a heater 130 is formed to encircle each nozzle 122 . The heaters 130 are used to generate bubbles in the ink. Preferably, these heaters 130 have a shape of a round-shaped ring and are formed of resistant heating elements, such as a polysilicon layer doped with impurities. Here, the impurity-doped polysilicon layer may be deposited to a predetermined thickness with a source gas such as phosphorous (P) as an impurity by a low-pressure chemical vapor deposition (LPCVD). The thickness of the polysilicon layer deposited is determined so as to have a proper resistance value in consideration of the width and length of the heater 130 . The polysilicon layer, which is deposited on the entire surface of the nozzle plate 120 , is patterned to a round ring shape by a photolithographical process using a photomask and photoresist and an etching process using a photoresist pattern as an etching mask.
[0037] On the nozzle plate 120 and the heater 130 , a silicon nitride layer may be formed as a first passivation layer 140 that protects the heater 130 . The first passivation layer 140 may also be deposited to a thickness of about 0.5 μm by a LPCVD.
[0038] Additionally, the heater 130 is connected to metal electrodes 150 so that a pulse current may be applied to the heater 130 . Here, the electrodes 150 are connected to the diameter of the heater 130 to face each other. More specifically, a portion of the first passivation layer 140 , which is formed of a silicon nitride layer, is etched to expose a portion of the heater 130 to which the electrode 150 is connected. Next, the electrode 150 is formed by depositing a metal material, which has excellent conductivity and is easily patterned, e.g., aluminum or an aluminum alloy, to a thickness of about 1 μm by a sputtering method and patterning the same. At the same time, the metal layer constituting the electrode 150 is patterned to form a wiring (not shown) and the bonding pad ( 120 of FIG. 2) on another portion of the substrate 110 .
[0039] A silicon oxide layer is formed on the first passivation layer 140 and the electrode 150 as a second passivation layer 160 . The second passivation layer 160 may be formed to a thickness of about 1 μm by a chemical vapor deposition at a low temperature, e.g., 400° C., within a range that the electrode 150 and the bonding pad 102 are not deformed.
[0040] After the second passivation layer 160 is formed, a photoresist pattern is formed on the resultant structure. Then, the first and second passivation layers 140 and 160 and the nozzle plate 120 are sequentially etched with the photoresist pattern as an etching mask to form the nozzle 122 having a diameter of between about 16-20 μm. Next, the ink chamber 114 and the ink channel 116 are formed via the nozzle 112 , as described above.
[0041] The bottom of the ink chamber 114 conforms to a hemispherical shape, but may additionally include nozzle guides 170 , which extend in the depth direction of the ink chamber 114 from the edges of the nozzle 122 , at an upper portion thereof. The droplet of ink may be precisely ejected in the vertical direction of the substrate 110 via the nozzles 122 due to the nozzle guide 170 . Such a nozzle guide 170 may be formed when the ink chamber 114 is made. That is, an exposed portion of the substrate 110 is anisotropically etched via the nozzle 122 to form a groove to a predetermined depth. Then, a predetermined layer, such as tetraethylortho silicate (TEOS) oxide layer, is deposited along the inner surface of the groove to a thickness of about 1 μm. Thereafter, the TEOS oxide layer formed at the bottom of the groove is etched and removed. As a result, the nozzle guide 170 , which is formed of the TEOS oxide layer, is formed along the inner circumference of the groove. Next, a portion of the substrate 110 that is exposed through the bottom of the groove is isotropically etched to form the ink chamber 114 having the nozzles guides 170 at upper portions thereof.
[0042] Hereinafter, a mechanism of ejecting an ink droplet from an ink-jet printhead according to the present invention will now be explained with reference to FIGS. 6A and 6B. Referring to FIG. 6A, ink 190 is supplied to an ink chamber 114 via a manifold 112 and an ink channel 116 due to capillary action. When the ink chamber 114 is filled with the ink 190 , a pulse current is applied to the heater 130 through the electrode 150 to generate heat in the heater 130 . The heat generated is transmitted to the ink 190 filled in the ink chamber 114 via a nozzle plate 120 below the heater 130 . As a result, the ink 190 boils to generate a bubble 195 in the ink chamber 114 . The shape of the bubble 195 varies depending on the shape of the heater 130 , but conforms to a doughnut shape in most cases.
[0043] The bubble 195 of a doughnut shape expands as time elapses. As shown in FIG. 6B, an ink droplet 191 is ejected from the ink chamber 114 via the nozzle 122 due to the pressure of the expanded bubble 196 . At this time, the ejection of the ink droplet 191 can be guided by the nozzle guide 170 , and thus, it is possible to eject the ink droplet 191 precisely in the vertical direction of the substrate 110 . Also, since the ink chamber 114 is formed as a hemisphere, it is possible to prevent backflow of ink, thereby reducing cross talk with adjacent ink ejectors. Furthermore, it is possible to more effectively prevent the back flow of the ink 190 in the case where the diameter of the ink channel 116 is smaller than that of the nozzle 122 .
[0044] In addition, since the heater 130 has a round ring shape, the heaters have a large surface area. Accordingly, the heaters 130 may be easily heated and cooled, so that a period of time during which the bubble 195 is generated, expands, and collapses, is reduced. Thus, an ink-jet printhead according to the present invention has a high driving frequency and is capable of ejecting ink on paper rapidly. The ink chamber 114 has a hemispherical shaped and thus, the bubble 195 may be more stably generated and expanded as compared to ink chambers of conventional ink-jet printhead having a hexahedron or a pyramid-type shape. Further, the bubbles 195 and 196 can be generated and expanded quickly, which enables rapid ejection of ink.
[0045] After the ink droplet 191 is ejected from the ink chamber 114 , the ink 190 is cooled and then, the expanded bubble 196 collapses or breaks when a current, which was applied to the heater 130 , is blocked. Next, the ink chamber 114 is filled with the ink 190 again.
[0046] In conclusion, a high-density ink-jet printhead according to the present invention has the following advantageous. First, a plurality of nozzles are arranged on one ink supply manifold in a plurality of rows, and thus, the density of nozzles may be increased, thereby enhancing the printing speed and providing high resolution printing quality. Second, a substrate having ink chambers and ink channels, a nozzle plate, heaters and electrodes are united on a silicon substrate. Therefore, an ink-jet printhead according to the present invention is easy to manufacture, and further, problems due to misalignment of components may be reduced. Also, such an ink-jet printhead is capable of being mass-produced because a substrate thereof can be a silicon wafer such as are adopted in a process of manufacturing semiconductor devices. Third, in an ink-jet printhead according to the present invention, a heater is formed in a ring shape and an ink chamber is formed in a hemispherical shape. Accordingly, the expansion of bubbles is limited to within the ink chamber, thereby preventing any back flow of ink filled in the ink chamber. Thus, such an ink-jet printhead is free from cross talk resulting from adjacent ink ejectors. Moreover, the direction of ejection of an ink droplet may be guided by nozzle guides, thereby ejecting ink precisely in the vertical direction of a substrate.
[0047] A preferred embodiment of the present invention has been disclosed herein and, although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. For example, alternate materials may be used as materials for use in elements of the printhead according to the present invention. That is, the substrate may be formed of another material having a good processing property, as well as silicon, and the same applies to the heater, electrodes, the silicon oxide layer, and the silicon nitride layer. In addition, the described method for stacking and forming materials is only for explanatory reasons, and various deposition and etching methods may be used. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims. | A high-density ink-jet printhead, in which a plurality of nozzles, through which ink is ejected, are arrayed on an ink supply manifold in a plurality of rows is provided, wherein the ink-jet printhead includes a substrate; hemispherical ink chambers at a surface of the substrate; a manifold for supplying ink to the ink chambers; ink channels to be in flow communication with the ink chambers and the manifold; a nozzle plate monolithically formed with the substrate; nozzles formed on the nozzle plate, each formed to correspond to a center of each of the ink chambers; heaters formed on the nozzle plate, each having a ring shape and encircling a corresponding nozzle; and electrodes, positioned on the nozzle plate and electrically connected to the heaters, for applying current to the heaters, wherein the nozzles are arrayed on the manifold in at least in three rows, and preferably in five rows. | Summarize the patent document, focusing on the invention's functionality and advantages. | [
"BACKGROUND OF THE INVENTION [0001] 1.",
"Field of the Invention [0002] The present invention relates to a bubble jet type ink-jet printhead.",
"More particularly, the present invention relates to a high-density ink-jet printhead in which a plurality of nozzles, through which ink is ejected, are arrayed on an ink supply manifold in a plurality of rows, thereby increasing the number of nozzles per unit area.",
"[0003] 2.",
"Description of the Related Art [0004] In general, ink-jet printheads are apparatuses that eject a fine droplet of printer ink on a desired position of a paper to print an image containing one or more predetermined colors.",
"To eject ink onto the paper, an ink-jet printer generally adopts an electro-thermal transducer method that ejects ink onto the paper by generating a bubble in ink using a heat source (this method is called a bubble jet type), or an electromechanical transducer method that ejects ink onto the paper using a change in the volume of ink due to the deformation of a piezoelectric body.",
"[0005] In a bubble-jet type ink ejection mechanism, as mentioned above, when power is applied to a heater including a resistance heating element, ink adjacent to the heater is rapidly heated to about 300° C. Heating the ink generates bubbles, which grow and swell, and thus apply pressure in the ink chamber filled with the ink.",
"As a result, ink adjacent to a nozzle is ejected from the ink chamber through the nozzle.",
"[0006] There are multiple factors and parameters to consider in making an ink-jet printhead having an ink ejecting unit in a bubble-jet mode.",
"First, it should be simple to manufacture, have a low manufacturing cost, and be capable of being mass-produced.",
"Second, in order to produce high quality color images, the formation of undesirable satellite ink droplets that usually accompany an ejected main ink droplet must be avoided during the printing process.",
"Third, cross-talk between adjacent nozzles, from which ink is not ejected, must be avoided, when ink is ejected from one nozzle, or when an ink chamber is refilled with ink after ink is ejected.",
"For this purpose, ink back flow, i.e., when ink flows in a direction opposite to the direction in which ink is ejected, should be prevented.",
"Fourth, for high-speed printing, the refilling period after ink is ejected should be as short a period of time as possible to increase the printing speed.",
"That is, the driving frequency of the printhead should be high.",
"[0007] The above requirements, however, tend to conflict with one another.",
"Furthermore, the performance of an ink-jet printhead is closely related to and affected by the structure and design, e.g., the relative sizes of ink chamber, ink passage, and heater, etc.",
", as well as by the formation and expansion shape of the bubbles.",
"[0008] [0008 ]FIG. 1A illustrates an exploded perspective view of a structure of an ink ejector of a conventional bubble jet type ink-jet printhead according to the prior art.",
"FIG. 1B illustrates a cross-sectional view for explaining a process of ejecting an ink droplet from a conventional bubble jet type ink-jet printhead.",
"FIG. 1C illustrates a plan view of the arrangement of a plurality of nozzles in the conventional ink-jet printhead of FIG. 1A.",
"[0009] A conventional bubble jet type ink-jet printhead shown in FIGS. 1A through 1C includes a substrate 10 , barrier walls 38 that are formed on the substrate 10 and that form ink chambers 26 , which are filled with ink 49 , heaters 12 formed in the ink chambers 26 , and a nozzle plate 18 having nozzles 16 from which an ink droplet 49 ′ is ejected.",
"The ink 49 is supplied to the ink chambers 26 via ink channels 24 from ink supply manifolds 14 in flow communication with an ink storage unit (not shown).",
"As a result, the nozzles 16 , which are in flow communication with the ink chambers 26 , are also filled with the ink 49 due to capillary action.",
"In the above ink-jet printhead, a plurality of heaters 12 and a plurality of ink chambers 26 are formed to correspond to the plurality of nozzles 16 , and are arranged in a row, adjacent to each of the ink supply manifolds 14 .",
"[0010] In operation of the above ink-jet printhead, the heaters 12 are supplied with current and heated to form bubbles 48 in the ink 49 filled in the ink chambers 26 .",
"Then, the bubbles 48 expand and put pressure on the ink 49 filled in the ink chambers 26 , thereby ejecting an ink droplet 49 ′ to the outside via the nozzles 16 .",
"Then, the ink 49 flows through the ink channels 24 to fill the ink chambers 26 .",
"[0011] A process of manufacturing a conventional printhead having the above structure, however, is complicated because the nozzle plate 18 and the substrate 10 are individually made and then bonded together.",
"In particular, the nozzle plate 18 may be misaligned with respect to the substrate 10 during manufacture.",
"[0012] Additionally, as previously mentioned, the plurality of nozzles 16 , heaters 12 and ink chambers 26 are arranged on each manifold 14 in a row, but may be arranged at both sides of each manifold 14 in a row.",
"With such a structure, however, there is a limitation in increasing the number of nozzles per unit area, i.e., the density of a nozzle.",
"Accordingly, it is difficult to realize a high-density ink-jet printhead that prints quickly and has high resolution.",
"SUMMARY OF THE INVENTION [0013] In an effort to solve the above problems, it is a feature of an embodiment of the present invention to provide a high-density ink-jet printhead in which hemispherical ink chambers are formed that satisfy the above conditions, and a plurality of nozzles are arranged on each ink supply manifold in a plurality of rows, thereby increasing the density of nozzles.",
"[0014] To provide the above feature, there is provided an ink-jet printhead including a substrate;",
"a plurality of ink chambers formed in a hemispherical shape at a surface of the substrate and filled with ink;",
"a manifold formed at a rear surface of the substrate, the manifold for supplying ink to the plurality of ink chambers;",
"a plurality of ink channels each formed at a bottom of each of the plurality of ink chambers to be in flow communication with the manifold;",
"a nozzle plate monolithically formed with the substrate;",
"a plurality of nozzles formed on the nozzle plate, each formed to correspond to a center of each of the plurality of ink chambers;",
"a plurality of heaters formed on the nozzle plate, each of the plurality of heaters having a ring shape and encircling a corresponding one of the plurality of nozzles;",
"and a plurality of electrodes positioned on the nozzle plate and electrically connected to the plurality of heaters, the plurality of electrodes applying current to the heaters.",
"[0015] In an embodiment of the present invention, the plurality of nozzles are arrayed on the manifold in at least three rows.",
"In a preferred embodiment of the present invention, the plurality of nozzles are arrayed on the manifold in five rows.",
"[0016] Preferably, the substrate is a silicon wafer and the nozzle plate is a silicon oxide layer formed by oxidizing a surface of the silicon wafer.",
"[0017] Preferably, each of the plurality of nozzles may have a nozzle guide extending in the depth direction of the ink chamber, at each edge of the plurality of nozzles.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0018] The above features and advantages of the present invention will become readily apparent to those of ordinary skill in the art by describing in detail preferred embodiments thereof with reference to the attached drawings in which: [0019] [0019 ]FIG. 1A illustrates an exploded perspective view of an ink ejector of a conventional bubble jet type ink-jet printhead;",
"[0020] [0020 ]FIG. 1B illustrates a cross-sectional view for explaining a process of ejecting an ink droplet from the ink-jet printhead of FIG. 1;",
"[0021] [0021 ]FIG. 1C illustrates a plan view of the conventional ink-jet printhead of FIG. 1A showing an arrangement of a plurality of nozzles;",
"[0022] [0022 ]FIG. 2 illustrates a plan view of an ink-jet printhead according to a preferred embodiment of the present invention;",
"[0023] [0023 ]FIG. 3 illustrates a cross-sectional view of the ink-jet printhead of FIG. 2, taken along line A-A′;",
"[0024] [0024 ]FIG. 4 illustrates a plan view of a unit ink ejector of the ink-jet printhead of FIG. 2;",
"[0025] [0025 ]FIG. 5 illustrates a cross-sectional view of the unit ink ejector of FIG. 4, taken along line B-B′;",
"and [0026] [0026 ]FIGS. 6A and 6B illustrate cross-sectional views of the mechanism of ejecting ink from an ink ejector having the structure shown in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION [0027] Korean Patent Application No. 2001-66747, filed Oct. 29, 2001, and entitled: “High-Density Ink-jet Printhead having Multi-Arrayed Structure,” is incorporated by reference herein in its entirety.",
"[0028] Hereinafter, the present invention will be described in detail by describing a preferred embodiment of the present invention with reference to the accompanying drawings.",
"Like reference numerals refer to like elements throughout the drawings.",
"In the drawings, the shape and thickness of an element may be exaggerated for clarity and convenience.",
"Further, it will be understood that when a layer is referred to as being on another layer or “on”",
"a substrate, it may be directly on the other layer or on the substrate, or intervening layers may also be present.",
"[0029] [0029 ]FIG. 2 illustrates a plan view of an ink-jet printhead according to a preferred embodiment of the present invention.",
"FIG. 3 illustrates a cross-sectional view of the ink-jet printhead of FIG. 2, taken along line A-A′.",
"[0030] Referring to FIGS. 2 and 3, in the ink-jet printhead according to a preferred embodiment of the present invention, five rows of ink ejectors 100 are arranged in a zigzag pattern on an ink supply manifold 112 , which is illustrated by dotted lines.",
"Bonding pads 102 that are connected to each ink ejector 100 and are to be bonded with wires are positioned at both sides of each ink ejector 100 .",
"Additionally, the manifold 112 is in flow communication with an ink storage unit (not shown) filled with ink.",
"[0031] The manifold 112 is formed at a rear surface of a substrate 110 , and a nozzle plate 120 having a plurality of nozzles 122 is formed on an opposing surface of the substrate 110 .",
"Each one of a plurality of heaters 130 encircles a corresponding one of the plurality of nozzles 122 , which are formed on the nozzle plate 120 .",
"Also, hemispherical ink chambers 114 , each one corresponding to one of the plurality of nozzles 122 , are formed on the substrate 110 .",
"A plurality of ink channels 116 are formed to pass through a bottom of each ink chamber 114 , which are in flow communication with the manifold 112 .",
"[0032] The plurality of nozzles 122 are arrayed to be positioned on one manifold 112 in at least three rows, and preferably in five rows, as shown in FIG. 3. Further, the plurality of nozzles 122 may be freely arranged according to a printing algorithm for realizing an image.",
"Since the plurality of nozzles 122 have a two-dimensional multi-array structure, it is possible to increase the number of nozzles per unit area, thereby enhancing the speed of printing and realizing a high-density ink-jet printhead having high resolution.",
"[0033] [0033 ]FIG. 4 illustrates a plan view of a unit ink ejector 100 of FIG. 2. FIG. 5 illustrates a cross-sectional view of the vertical structure of the unit ink ejector 100 of FIG. 4, taken along line B-B′.",
"Referring to FIGS. 4 and 5, an ink chamber 114 , which is filled with ink, is formed on a substrate 110 of the ink ejector 100 , and a manifold 112 , which supplies ink to the ink chamber 114 , is formed at a rear surface of the substrate 110 .",
"In addition, a manifold 112 and an ink channel 116 , which connects the ink chamber 114 and the manifold 112 , are formed at a center of a bottom of the ink chamber 114 .",
"Preferably, the ink chamber 114 is hemispherical shaped.",
"[0034] Also preferably, the substrate 110 is formed of a silicon material that is used in fabricating an integrated circuit.",
"For instance, the substrate 110 may be a silicon substrate of a crystal orientation of (100) and a thickness of about 500 μm.",
"Use of a silicon wafer as the substrate 110 facilitates mass-production of the ink ejectors 100 .",
"The ink chamber 114 may be formed by isotropically etching the surface of the substrate 110 that is exposed via the plurality of nozzles 122 , which are formed on a nozzle plate.",
"Formation of the plurality of nozzles 122 will be explained later.",
"The manifold 112 is formed by anisotropically etching the rear surface of the substrate 110 or by etching the rear surface of the substrate 110 to have a predetermined inclination.",
"Here, the ink chamber 114 is formed in a hemispherical shape having a depth and a radius of about 20 μm.",
"Alternatively, the ink chamber 114 may be formed by anisotropically etching the substrate 110 to a predetermined depth and then, isotropically etching the etched substrate 110 .",
"The ink channel 116 may be formed by anistropically etching a center of a bottom of the ink chamber 114 via the nozzle 122 .",
"The diameter of the ink channel 116 is the same as or slightly smaller than that of the nozzle 122 , thereby preventing ejected ink from flowing back into the ink channel 116 .",
"The diameter of the ink channel 116 affects the speed of refilling ink after the ejecting of the ink, and thus must be precisely controlled.",
"[0035] At a surface of the substrate 110 , a nozzle plate 120 having the plurality of nozzles 122 is formed to provide the upper walls of the ink chamber 114 .",
"When the substrate 110 is formed of silicon, the nozzle plate 120 may be a silicon oxide layer that is formed by oxidizing the silicon substrate 110 .",
"More particularly, a silicon wafer is wet or dry-oxidized in an oxidation furnace, thereby forming an oxide layer on the silicon substrate 110 , and thus the nozzle plate 120 .",
"[0036] On the nozzle plate 120 , a heater 130 is formed to encircle each nozzle 122 .",
"The heaters 130 are used to generate bubbles in the ink.",
"Preferably, these heaters 130 have a shape of a round-shaped ring and are formed of resistant heating elements, such as a polysilicon layer doped with impurities.",
"Here, the impurity-doped polysilicon layer may be deposited to a predetermined thickness with a source gas such as phosphorous (P) as an impurity by a low-pressure chemical vapor deposition (LPCVD).",
"The thickness of the polysilicon layer deposited is determined so as to have a proper resistance value in consideration of the width and length of the heater 130 .",
"The polysilicon layer, which is deposited on the entire surface of the nozzle plate 120 , is patterned to a round ring shape by a photolithographical process using a photomask and photoresist and an etching process using a photoresist pattern as an etching mask.",
"[0037] On the nozzle plate 120 and the heater 130 , a silicon nitride layer may be formed as a first passivation layer 140 that protects the heater 130 .",
"The first passivation layer 140 may also be deposited to a thickness of about 0.5 μm by a LPCVD.",
"[0038] Additionally, the heater 130 is connected to metal electrodes 150 so that a pulse current may be applied to the heater 130 .",
"Here, the electrodes 150 are connected to the diameter of the heater 130 to face each other.",
"More specifically, a portion of the first passivation layer 140 , which is formed of a silicon nitride layer, is etched to expose a portion of the heater 130 to which the electrode 150 is connected.",
"Next, the electrode 150 is formed by depositing a metal material, which has excellent conductivity and is easily patterned, e.g., aluminum or an aluminum alloy, to a thickness of about 1 μm by a sputtering method and patterning the same.",
"At the same time, the metal layer constituting the electrode 150 is patterned to form a wiring (not shown) and the bonding pad ( 120 of FIG. 2) on another portion of the substrate 110 .",
"[0039] A silicon oxide layer is formed on the first passivation layer 140 and the electrode 150 as a second passivation layer 160 .",
"The second passivation layer 160 may be formed to a thickness of about 1 μm by a chemical vapor deposition at a low temperature, e.g., 400° C., within a range that the electrode 150 and the bonding pad 102 are not deformed.",
"[0040] After the second passivation layer 160 is formed, a photoresist pattern is formed on the resultant structure.",
"Then, the first and second passivation layers 140 and 160 and the nozzle plate 120 are sequentially etched with the photoresist pattern as an etching mask to form the nozzle 122 having a diameter of between about 16-20 μm.",
"Next, the ink chamber 114 and the ink channel 116 are formed via the nozzle 112 , as described above.",
"[0041] The bottom of the ink chamber 114 conforms to a hemispherical shape, but may additionally include nozzle guides 170 , which extend in the depth direction of the ink chamber 114 from the edges of the nozzle 122 , at an upper portion thereof.",
"The droplet of ink may be precisely ejected in the vertical direction of the substrate 110 via the nozzles 122 due to the nozzle guide 170 .",
"Such a nozzle guide 170 may be formed when the ink chamber 114 is made.",
"That is, an exposed portion of the substrate 110 is anisotropically etched via the nozzle 122 to form a groove to a predetermined depth.",
"Then, a predetermined layer, such as tetraethylortho silicate (TEOS) oxide layer, is deposited along the inner surface of the groove to a thickness of about 1 μm.",
"Thereafter, the TEOS oxide layer formed at the bottom of the groove is etched and removed.",
"As a result, the nozzle guide 170 , which is formed of the TEOS oxide layer, is formed along the inner circumference of the groove.",
"Next, a portion of the substrate 110 that is exposed through the bottom of the groove is isotropically etched to form the ink chamber 114 having the nozzles guides 170 at upper portions thereof.",
"[0042] Hereinafter, a mechanism of ejecting an ink droplet from an ink-jet printhead according to the present invention will now be explained with reference to FIGS. 6A and 6B.",
"Referring to FIG. 6A, ink 190 is supplied to an ink chamber 114 via a manifold 112 and an ink channel 116 due to capillary action.",
"When the ink chamber 114 is filled with the ink 190 , a pulse current is applied to the heater 130 through the electrode 150 to generate heat in the heater 130 .",
"The heat generated is transmitted to the ink 190 filled in the ink chamber 114 via a nozzle plate 120 below the heater 130 .",
"As a result, the ink 190 boils to generate a bubble 195 in the ink chamber 114 .",
"The shape of the bubble 195 varies depending on the shape of the heater 130 , but conforms to a doughnut shape in most cases.",
"[0043] The bubble 195 of a doughnut shape expands as time elapses.",
"As shown in FIG. 6B, an ink droplet 191 is ejected from the ink chamber 114 via the nozzle 122 due to the pressure of the expanded bubble 196 .",
"At this time, the ejection of the ink droplet 191 can be guided by the nozzle guide 170 , and thus, it is possible to eject the ink droplet 191 precisely in the vertical direction of the substrate 110 .",
"Also, since the ink chamber 114 is formed as a hemisphere, it is possible to prevent backflow of ink, thereby reducing cross talk with adjacent ink ejectors.",
"Furthermore, it is possible to more effectively prevent the back flow of the ink 190 in the case where the diameter of the ink channel 116 is smaller than that of the nozzle 122 .",
"[0044] In addition, since the heater 130 has a round ring shape, the heaters have a large surface area.",
"Accordingly, the heaters 130 may be easily heated and cooled, so that a period of time during which the bubble 195 is generated, expands, and collapses, is reduced.",
"Thus, an ink-jet printhead according to the present invention has a high driving frequency and is capable of ejecting ink on paper rapidly.",
"The ink chamber 114 has a hemispherical shaped and thus, the bubble 195 may be more stably generated and expanded as compared to ink chambers of conventional ink-jet printhead having a hexahedron or a pyramid-type shape.",
"Further, the bubbles 195 and 196 can be generated and expanded quickly, which enables rapid ejection of ink.",
"[0045] After the ink droplet 191 is ejected from the ink chamber 114 , the ink 190 is cooled and then, the expanded bubble 196 collapses or breaks when a current, which was applied to the heater 130 , is blocked.",
"Next, the ink chamber 114 is filled with the ink 190 again.",
"[0046] In conclusion, a high-density ink-jet printhead according to the present invention has the following advantageous.",
"First, a plurality of nozzles are arranged on one ink supply manifold in a plurality of rows, and thus, the density of nozzles may be increased, thereby enhancing the printing speed and providing high resolution printing quality.",
"Second, a substrate having ink chambers and ink channels, a nozzle plate, heaters and electrodes are united on a silicon substrate.",
"Therefore, an ink-jet printhead according to the present invention is easy to manufacture, and further, problems due to misalignment of components may be reduced.",
"Also, such an ink-jet printhead is capable of being mass-produced because a substrate thereof can be a silicon wafer such as are adopted in a process of manufacturing semiconductor devices.",
"Third, in an ink-jet printhead according to the present invention, a heater is formed in a ring shape and an ink chamber is formed in a hemispherical shape.",
"Accordingly, the expansion of bubbles is limited to within the ink chamber, thereby preventing any back flow of ink filled in the ink chamber.",
"Thus, such an ink-jet printhead is free from cross talk resulting from adjacent ink ejectors.",
"Moreover, the direction of ejection of an ink droplet may be guided by nozzle guides, thereby ejecting ink precisely in the vertical direction of a substrate.",
"[0047] A preferred embodiment of the present invention has been disclosed herein and, although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation.",
"For example, alternate materials may be used as materials for use in elements of the printhead according to the present invention.",
"That is, the substrate may be formed of another material having a good processing property, as well as silicon, and the same applies to the heater, electrodes, the silicon oxide layer, and the silicon nitride layer.",
"In addition, the described method for stacking and forming materials is only for explanatory reasons, and various deposition and etching methods may be used.",
"Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims."
] |
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a Non-Provisional Utility application which claims benefit of co-pending U.S. patent application Ser. No. 60/526,638 filed Dec. 3, 2003, entitled “High Input Voltage Microcontroller Based Instant Start Ballast” which is hereby incorporated by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
REFERENCE TO SEQUENCE LISTING OR COMPUTER PROGRAM LISTING APPENDIX
Not Applicable
BACKGROUND OF THE INVENTION
Electronic ballasts are used to provide power to gas discharge lamps such as fluorescent lights. These ballasts often sense the voltage applied to the lamp to monitor the functioning of the lamp and ballast. To sense the lamp voltage with a microcontroller, prior art ballasts such as set forth in U.S. Pat. No. 5,925,990, sample the lamp voltage through a resistor connected in series with a resonant capacitor. The voltage across the resistor represents the current in a resonant inductor, which is in turn proportional to the voltage across the resonant capacitor. However, in order to fully utilize the resolution of the A/D converter of the microcontroller, the voltage drop across the resistor needs to be relatively high. As a result, more than 2 watts of power are typically consumed at the output of the resonant inverter which increases the required input power to the ballast. Therefore, since efficiency is very important in modern lighting designs, an improved method and apparatus for sensing lamp voltage that consumes less power is needed.
In some prior art ballasts, the voltage on the lamp voltage sensing resistor is also used to control the open circuit voltage during striking when no lamp is connected. To accomplish this, the pulse width of one or both switches of the half bridge is typically controlled. Controlling the pulse width controls the open circuit voltage indirectly by using inductor current to control the voltage on the capacitor. As a result, large open circuit voltage variations often result when external connections to the fixture, such as cables, add extra capacitance. In ballast implementations that can afford to use a large resonant capacitor and a small inductor, the open circuit voltage variation problem is generally not significant. However, potentially damaging hard switching or capacitive mode switching is often observed with this type of prior art open circuit voltage controlled ballast. Furthermore, the use of a large resonant capacitor makes the resonant tank difficult to design. As a result, these types of ballasts suffer from more conduction losses and/or hard switching during the striking of the lamp than do typical ballasts. Conduction losses and hard switching are undesirable in that they may ultimately cause the ballast to fail. A large resonant capacitor, with a striking voltage of two lamps across it, stores a substantial amount of energy. When the striking attempt occurs when there is no load, the striking energy is transferred to the resonant inductor and can saturate the inductor. The result is undesirable hard switching occurring during the striking. Even though a MOSFET can survive the high stress transients in ballasts with a 460V bulk voltage, hard switching is undesirable and should be avoided if possible since it may result in damage. Furthermore, for some types of ballasts, it is critically important to avoid hard switching due to their particular susceptibility to damage from transients. Thus, in many of the prior art ballasts, the resonant capacitor value is minimized and a cable compensation circuit is utilized to control the open circuit voltage such that it is constant with various lengths of connecting cables having varying amounts of capacitance. However, these circuits are often complex and decrease the efficiency while increasing the cost of the ballast. Therefore, an improved method and apparatus for sensing and controlling the open circuit voltage of a ballast is needed.
BRIEF SUMMARY OF THE INVENTION
A preferred embodiment of the present invention is directed toward an electronic ballast for producing an output voltage for igniting and powering gas discharge lamps connected between a pair of output terminals. The ballast includes a microcontroller for controlling the ballast. An inverter including a first and second transistor and a resonant tank having a tank inductor and a tank capacitor are also included. A sampling capacitor is connected in series with the tank capacitor and an output voltage of the electronic ballast is monitored across the sampling capacitor. A pair of snubber capacitors is provided to reduce turn off losses in the first and second transistors. One of the snubber capacitors is connected in parallel with the first transistor and the other of the snubber capacitors is connected in parallel with the second transistor. An extended dead time is created between gating signals of the first and second transistors to allow the snubber capacitors to discharge. An open circuit voltage control circuit is provided that controls the output voltage when a gas discharge lamp is not connected between the output terminals. The open circuit voltage control circuit includes a resistor connected in series with the sampling capacitor. A voltage across the resistor is used to trim a gating signal for at least one of the first and the second transistors. A cable compensation circuit is provided that limits variations in the output voltage due to cables being connected to the output terminals of the ballast.
Another embodiment of the present invention is directed toward an electronic ballast for providing an output voltage on a pair of output terminals for use in powering a gas discharge lamp. The ballast includes an inverter circuit having a first transistor and a second transistor. A lossless snubber circuit is used to reduce turn off losses in the inverter. A resonant tank having a tank capacitor is included. A sampling capacitor is connected in series with the tank capacitor. The output voltage of the ballast is monitored by monitoring a voltage across the sampling capacitor. A resistor and capacitor filter the voltage across the sampling capacitor such that it can be properly received by a microcontroller for analysis. An open circuit voltage control circuit controls a voltage across the output terminals of the electronic ballast when a gas discharge lamp is not connected between the output terminals. The open circuit voltage control circuit includes a resistor connected in series with the sampling capacitor. The electronic ballast further includes a cable compensation circuit for compensating for changes in the output voltage due to a cable being connected to the output terminals. The cable compensation circuit compensates for changes in the output voltage by altering gating signals of at least one of the transistors and, thereby, limiting fluctuations in the output voltage.
Yet another embodiment of the present invention is directed toward an electronic ballast having a pair of output terminals for providing power to gas discharge lamps. The ballast includes a microcontroller for controlling the ballast and a half-bridge inverter circuit having a pair of series connected transistors. A resonant tank circuit is connected between the series connected transistors. The resonant tank circuit includes a resonant inductor connected in series with a resonant capacitor. A sampling capacitor is connected in series with the resonant capacitor such that a voltage across the sampling capacitor is proportional to a voltage across the output terminals. The microcontroller monitors the voltage across the sampling capacitor. A resistive and capacitive filter filters the sampled voltage across the sampling capacitor before the sampled voltage is provided to the microcontroller. A resistor is connected in series with the sampling capacitor such that a voltage across the resistor is used to control an open circuit output voltage of the electronic ballast. An open circuit voltage control circuit produces a transistor gating signal based upon the voltage across the resistor that is used by gating logic to control the output voltage. A cable compensation circuit limits variations in the output voltage due to cables being connected to outputs of the ballast. The cable compensation circuit also limits variations in the output voltage by providing signals to the microcontroller that are used to alter the turn-on times of at least one of the pair of transistors.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a schematic diagram of a lossless lamp voltage sampling circuit for an A/D converter of a microcontroller constructed in accordance with a preferred embodiment of the present invention;
FIG. 2 is a schematic diagram of a lossless lamp voltage sampling circuit having open circuit voltage control circuitry constructed in accordance with an embodiment the present invention; and
FIG. 3 is a schematic of a lossless lamp voltage sensing circuit including a cable compensation circuit constructed in accordance with a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention is directed toward an instant start electronic ballast for a gas discharge lamp that overcomes the aforementioned deficiencies of the prior art. Referring now to FIG. 1 , an electronic ballast 2 that utilizes lossless sampling of the lamp voltage 4 in accordance with a preferred embodiment of the present invention is shown. The electronic ballast 2 includes a bulk DC voltage source 6 that provides power to the inverter circuit transistors 8 and 10 each of which is connected in parallel with a respective snubber capacitor 17 and 18 . In the normal case, the capacitors 17 and 18 reduce the turn-off losses associated with the switches 8 and 10 . However, all of the energy stored in the capacitors 17 and 18 when the switches 8 and 10 are turned off will be dissipated on the switches 8 and 10 at the turn-on. Thus, in a preferred embodiment such as an IHRV ballast, an extended dead time that allows the capacitors 17 and 18 to discharge is created between the gating signals of the transistors 8 and 10 to deal with this problem. Since the load current flowing through the lamp 14 is highly inductive during this extended dead time, the load 14 current will discharge the snubber capacitors 17 and 18 during the extended dead time.
The series resonant tank is comprised of a resonant tank inductor 12 and a resonant tank capacitor 14 . Prior art circuits use a resistor connected in series with the resonant capacitor 14 to sense the lamp voltage 4 and control the open circuit voltage. However, in a preferred embodiment of the present invention for an Instant-Start, High Range Voltage (IHRV) ballast and/or sign ballast, the lamp voltage 4 is sensed by a sampling capacitor 16 that is connected in series with the resonant capacitor 14 as shown in FIG. 1 . Using the principle of voltage division with capacitors, when the sampling capacitor 16 is much smaller than the resonant capacitor 14 , the voltage drop on the sampling capacitor 16 is very large compared to resonant capacitor 14 . This is beneficial in that it is relatively easy to find a film capacitor 16 that satisfies these criteria, has a small package size and is inexpensive. Moreover, the creation of large voltage drop across capacitor 16 provides a wide voltage range for the voltage sampling such that the full range of the A/D converter of the microcontroller 11 can be utilized. Most preferably, the capacitor 16 is a 330 nF 60V or a 680 nF 60V capacitor. A sampling circuit comprised of capacitors 20 and 22 and resistors 24 and 26 is used to condition and filter the sampled voltage on capacitor 16 for processing by the microcontroller. The sampling circuit of FIG. 1 provides a low output impedance, strong signal with an excellent signal to noise ratio and a quick response time to an AID converter input of an associated microcontroller 11 . More importantly, since the sampling is accomplished across the capacitor 16 , the sampling process is substantially lossless and does not significant decrease the efficiency of the ballast 2 . Thus, the circuit of FIG. 1 uses lossless capacitor based voltage division to improve the efficiency of the ballast 2 without sacrificing performance.
The sampling capacitor 16 used in the ballast of FIG. 1 can also be connected in series with a low value resistor 30 , which can be used to control the open circuit voltage 4 , as shown in FIG. 2 . The hybrid sampling circuit shown in FIG. 2 samples a large amplitude version of the lamp voltage 4 across capacitor 30 . The sampled signal is smoothed by RC filters constructed from capacitors 20 and 22 and resistors 24 and 26 and then fed to the A/D converter of the microcontroller. The response time of the sampled lamp voltage 4 is not fast, but it is almost entirely lossless. For open circuit voltage control, the amplitude of the voltage across resistor 30 is large enough at lamp striking to turn on transistor 36 and activate the gating logic 7 to trim the pulse width of the gating signal generated by the half-bridge driver 9 for the upper switch 8 of the half bridge. The exact value at which such gate signal trimming will occur is determined by the value of the resistors 32 and 34 which control the turning off and on of transistor 36 . Most preferably, resistors 32 and 34 both have a value of 1 kΩ. Trimming the pulse width of the gating signal of the upper switch 8 limits the open circuit voltage 4 . However, during steady state operation, the voltage on the resistor 30 is very small, out of phase with the voltage on capacitor 16 , and still proportional to the lamp voltage 4 . Hence, lamp voltage sensing is not affected by the resistor 30 when the ballast 2 is operating in the steady state.
The sampling circuit described above with respect to FIG. 2 can be used independently with or without a cable compensation circuit. Since the voltage on resistor 30 is in phase with the current of the upper switch 8 , it is convenient to use the voltage on resistor 30 to control the open circuit voltage 4 when no lamp is connected and to trim the pulse width of the upper switch 8 of the half-bridge as discussed above. However, when a long cable is connected and the capacitance of the cable is essentially in parallel with the resonant capacitor 14 , the parameters of the resonant tank constructed from inductor 12 and capacitor 14 changes. As a result, the open circuit voltage 34 decreases when a cable is connected to the ballast 2 . When the value of the resonant capacitor 14 is small, the decrease in the open circuit voltage 34 is significant and the ballast will not strike the lamp. The open circuit voltage 4 can be set high to start a lamp with a long cable. However, in applications where no cable is attached, the open circuit voltage 4 will then be too high, which may cause the ballast to fail the through-lamp leakage test, or damage the sampling film capacitor 16 . Increasing the capacitance of the resonant capacitor 14 helps to decrease the variation of the open circuit voltage but increases the conduction losses due to the circulation currents in the resonant capacitor 14 . Furthermore, larger capacitor values lead to saturation of the resonant inductor 12 . Therefore, the most preferred embodiments of the present invention include a cable compensation circuits.
Capacitor sampling provides a strong sample signal with low output impedance and quick response. A cable compensation circuit is created by adding zener diode 44 , resistors 42 and 46 , and capacitor 40 as shown in FIG. 3 . The open circuit voltage 4 as sampled by capacitor 16 rises very rapidly at node 48 . When the open circuit voltage 4 becomes too high, the zener diode 44 starts to conduct and feeds current to the base of transistor 36 such that the conductive threshold for the transistor 36 is decreased. Thus, the transistor 36 starts to turn-on earlier when the voltage on resistor 30 is lower. The pulse width of the gating signal of the upper switch 8 then becomes narrower thereby reducing the open circuit voltage 4 . So, the true open circuit voltage 4 is sensed in this way to change the current threshold required to turn-off the switch 8 . In an exemplary circuit constructed as described above, the open circuit voltage 4 varies from 1.9 kv to 2.6 kv without the cable compensation circuit of FIG. 3 when 18 feet of cable is connected to or removed from the circuit.. However, with the cable compensation circuit of FIG. 3 , the variation in the open circuit voltage 4 is within approximately 100V. Thus, an electronic ballast having a lossless voltage sampling and control circuit and a cable compensation circuit in accordance with the preferred embodiment of the present invention as shown in FIG. 3 represents a substantial improvement upon the prior art.
Thus, although there have been described particular embodiments of the present invention of a new and useful Lossless Circuit for Sampling of Lamp Voltage, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims. | An electronic ballast has a resonant tank circuit that includes a tank inductor and a tank capacitor connected in series. Lossless sampling of the output voltage of the electronic ballast is achieved by monitoring the voltage across a sampling capacitor placed in series with the tank capacitor. A resistive and capacitive filter is used to filter the monitored voltage such that it can be accurately received by a microcontroller. A resistor is connected in series with the sampling capacitor to produce an open circuit output voltage control signal that is used by the microcontroller to limit the open circuit output voltage. A cable compensation circuit is utilized to minimize variations in the open circuit voltage due to the connecting and disconnecting of a cable to the ballast output terminals. | Condense the core contents of the given document. | [
"CROSS-REFERENCES TO RELATED APPLICATIONS This application is a Non-Provisional Utility application which claims benefit of co-pending U.S. patent application Ser.",
"No. 60/526,638 filed Dec. 3, 2003, entitled “High Input Voltage Microcontroller Based Instant Start Ballast”",
"which is hereby incorporated by reference.",
"STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not Applicable REFERENCE TO SEQUENCE LISTING OR COMPUTER PROGRAM LISTING APPENDIX Not Applicable BACKGROUND OF THE INVENTION Electronic ballasts are used to provide power to gas discharge lamps such as fluorescent lights.",
"These ballasts often sense the voltage applied to the lamp to monitor the functioning of the lamp and ballast.",
"To sense the lamp voltage with a microcontroller, prior art ballasts such as set forth in U.S. Pat. No. 5,925,990, sample the lamp voltage through a resistor connected in series with a resonant capacitor.",
"The voltage across the resistor represents the current in a resonant inductor, which is in turn proportional to the voltage across the resonant capacitor.",
"However, in order to fully utilize the resolution of the A/D converter of the microcontroller, the voltage drop across the resistor needs to be relatively high.",
"As a result, more than 2 watts of power are typically consumed at the output of the resonant inverter which increases the required input power to the ballast.",
"Therefore, since efficiency is very important in modern lighting designs, an improved method and apparatus for sensing lamp voltage that consumes less power is needed.",
"In some prior art ballasts, the voltage on the lamp voltage sensing resistor is also used to control the open circuit voltage during striking when no lamp is connected.",
"To accomplish this, the pulse width of one or both switches of the half bridge is typically controlled.",
"Controlling the pulse width controls the open circuit voltage indirectly by using inductor current to control the voltage on the capacitor.",
"As a result, large open circuit voltage variations often result when external connections to the fixture, such as cables, add extra capacitance.",
"In ballast implementations that can afford to use a large resonant capacitor and a small inductor, the open circuit voltage variation problem is generally not significant.",
"However, potentially damaging hard switching or capacitive mode switching is often observed with this type of prior art open circuit voltage controlled ballast.",
"Furthermore, the use of a large resonant capacitor makes the resonant tank difficult to design.",
"As a result, these types of ballasts suffer from more conduction losses and/or hard switching during the striking of the lamp than do typical ballasts.",
"Conduction losses and hard switching are undesirable in that they may ultimately cause the ballast to fail.",
"A large resonant capacitor, with a striking voltage of two lamps across it, stores a substantial amount of energy.",
"When the striking attempt occurs when there is no load, the striking energy is transferred to the resonant inductor and can saturate the inductor.",
"The result is undesirable hard switching occurring during the striking.",
"Even though a MOSFET can survive the high stress transients in ballasts with a 460V bulk voltage, hard switching is undesirable and should be avoided if possible since it may result in damage.",
"Furthermore, for some types of ballasts, it is critically important to avoid hard switching due to their particular susceptibility to damage from transients.",
"Thus, in many of the prior art ballasts, the resonant capacitor value is minimized and a cable compensation circuit is utilized to control the open circuit voltage such that it is constant with various lengths of connecting cables having varying amounts of capacitance.",
"However, these circuits are often complex and decrease the efficiency while increasing the cost of the ballast.",
"Therefore, an improved method and apparatus for sensing and controlling the open circuit voltage of a ballast is needed.",
"BRIEF SUMMARY OF THE INVENTION A preferred embodiment of the present invention is directed toward an electronic ballast for producing an output voltage for igniting and powering gas discharge lamps connected between a pair of output terminals.",
"The ballast includes a microcontroller for controlling the ballast.",
"An inverter including a first and second transistor and a resonant tank having a tank inductor and a tank capacitor are also included.",
"A sampling capacitor is connected in series with the tank capacitor and an output voltage of the electronic ballast is monitored across the sampling capacitor.",
"A pair of snubber capacitors is provided to reduce turn off losses in the first and second transistors.",
"One of the snubber capacitors is connected in parallel with the first transistor and the other of the snubber capacitors is connected in parallel with the second transistor.",
"An extended dead time is created between gating signals of the first and second transistors to allow the snubber capacitors to discharge.",
"An open circuit voltage control circuit is provided that controls the output voltage when a gas discharge lamp is not connected between the output terminals.",
"The open circuit voltage control circuit includes a resistor connected in series with the sampling capacitor.",
"A voltage across the resistor is used to trim a gating signal for at least one of the first and the second transistors.",
"A cable compensation circuit is provided that limits variations in the output voltage due to cables being connected to the output terminals of the ballast.",
"Another embodiment of the present invention is directed toward an electronic ballast for providing an output voltage on a pair of output terminals for use in powering a gas discharge lamp.",
"The ballast includes an inverter circuit having a first transistor and a second transistor.",
"A lossless snubber circuit is used to reduce turn off losses in the inverter.",
"A resonant tank having a tank capacitor is included.",
"A sampling capacitor is connected in series with the tank capacitor.",
"The output voltage of the ballast is monitored by monitoring a voltage across the sampling capacitor.",
"A resistor and capacitor filter the voltage across the sampling capacitor such that it can be properly received by a microcontroller for analysis.",
"An open circuit voltage control circuit controls a voltage across the output terminals of the electronic ballast when a gas discharge lamp is not connected between the output terminals.",
"The open circuit voltage control circuit includes a resistor connected in series with the sampling capacitor.",
"The electronic ballast further includes a cable compensation circuit for compensating for changes in the output voltage due to a cable being connected to the output terminals.",
"The cable compensation circuit compensates for changes in the output voltage by altering gating signals of at least one of the transistors and, thereby, limiting fluctuations in the output voltage.",
"Yet another embodiment of the present invention is directed toward an electronic ballast having a pair of output terminals for providing power to gas discharge lamps.",
"The ballast includes a microcontroller for controlling the ballast and a half-bridge inverter circuit having a pair of series connected transistors.",
"A resonant tank circuit is connected between the series connected transistors.",
"The resonant tank circuit includes a resonant inductor connected in series with a resonant capacitor.",
"A sampling capacitor is connected in series with the resonant capacitor such that a voltage across the sampling capacitor is proportional to a voltage across the output terminals.",
"The microcontroller monitors the voltage across the sampling capacitor.",
"A resistive and capacitive filter filters the sampled voltage across the sampling capacitor before the sampled voltage is provided to the microcontroller.",
"A resistor is connected in series with the sampling capacitor such that a voltage across the resistor is used to control an open circuit output voltage of the electronic ballast.",
"An open circuit voltage control circuit produces a transistor gating signal based upon the voltage across the resistor that is used by gating logic to control the output voltage.",
"A cable compensation circuit limits variations in the output voltage due to cables being connected to outputs of the ballast.",
"The cable compensation circuit also limits variations in the output voltage by providing signals to the microcontroller that are used to alter the turn-on times of at least one of the pair of transistors.",
"BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a schematic diagram of a lossless lamp voltage sampling circuit for an A/D converter of a microcontroller constructed in accordance with a preferred embodiment of the present invention;",
"FIG. 2 is a schematic diagram of a lossless lamp voltage sampling circuit having open circuit voltage control circuitry constructed in accordance with an embodiment the present invention;",
"and FIG. 3 is a schematic of a lossless lamp voltage sensing circuit including a cable compensation circuit constructed in accordance with a preferred embodiment of the present invention.",
"DETAILED DESCRIPTION OF THE INVENTION A preferred embodiment of the present invention is directed toward an instant start electronic ballast for a gas discharge lamp that overcomes the aforementioned deficiencies of the prior art.",
"Referring now to FIG. 1 , an electronic ballast 2 that utilizes lossless sampling of the lamp voltage 4 in accordance with a preferred embodiment of the present invention is shown.",
"The electronic ballast 2 includes a bulk DC voltage source 6 that provides power to the inverter circuit transistors 8 and 10 each of which is connected in parallel with a respective snubber capacitor 17 and 18 .",
"In the normal case, the capacitors 17 and 18 reduce the turn-off losses associated with the switches 8 and 10 .",
"However, all of the energy stored in the capacitors 17 and 18 when the switches 8 and 10 are turned off will be dissipated on the switches 8 and 10 at the turn-on.",
"Thus, in a preferred embodiment such as an IHRV ballast, an extended dead time that allows the capacitors 17 and 18 to discharge is created between the gating signals of the transistors 8 and 10 to deal with this problem.",
"Since the load current flowing through the lamp 14 is highly inductive during this extended dead time, the load 14 current will discharge the snubber capacitors 17 and 18 during the extended dead time.",
"The series resonant tank is comprised of a resonant tank inductor 12 and a resonant tank capacitor 14 .",
"Prior art circuits use a resistor connected in series with the resonant capacitor 14 to sense the lamp voltage 4 and control the open circuit voltage.",
"However, in a preferred embodiment of the present invention for an Instant-Start, High Range Voltage (IHRV) ballast and/or sign ballast, the lamp voltage 4 is sensed by a sampling capacitor 16 that is connected in series with the resonant capacitor 14 as shown in FIG. 1 .",
"Using the principle of voltage division with capacitors, when the sampling capacitor 16 is much smaller than the resonant capacitor 14 , the voltage drop on the sampling capacitor 16 is very large compared to resonant capacitor 14 .",
"This is beneficial in that it is relatively easy to find a film capacitor 16 that satisfies these criteria, has a small package size and is inexpensive.",
"Moreover, the creation of large voltage drop across capacitor 16 provides a wide voltage range for the voltage sampling such that the full range of the A/D converter of the microcontroller 11 can be utilized.",
"Most preferably, the capacitor 16 is a 330 nF 60V or a 680 nF 60V capacitor.",
"A sampling circuit comprised of capacitors 20 and 22 and resistors 24 and 26 is used to condition and filter the sampled voltage on capacitor 16 for processing by the microcontroller.",
"The sampling circuit of FIG. 1 provides a low output impedance, strong signal with an excellent signal to noise ratio and a quick response time to an AID converter input of an associated microcontroller 11 .",
"More importantly, since the sampling is accomplished across the capacitor 16 , the sampling process is substantially lossless and does not significant decrease the efficiency of the ballast 2 .",
"Thus, the circuit of FIG. 1 uses lossless capacitor based voltage division to improve the efficiency of the ballast 2 without sacrificing performance.",
"The sampling capacitor 16 used in the ballast of FIG. 1 can also be connected in series with a low value resistor 30 , which can be used to control the open circuit voltage 4 , as shown in FIG. 2 .",
"The hybrid sampling circuit shown in FIG. 2 samples a large amplitude version of the lamp voltage 4 across capacitor 30 .",
"The sampled signal is smoothed by RC filters constructed from capacitors 20 and 22 and resistors 24 and 26 and then fed to the A/D converter of the microcontroller.",
"The response time of the sampled lamp voltage 4 is not fast, but it is almost entirely lossless.",
"For open circuit voltage control, the amplitude of the voltage across resistor 30 is large enough at lamp striking to turn on transistor 36 and activate the gating logic 7 to trim the pulse width of the gating signal generated by the half-bridge driver 9 for the upper switch 8 of the half bridge.",
"The exact value at which such gate signal trimming will occur is determined by the value of the resistors 32 and 34 which control the turning off and on of transistor 36 .",
"Most preferably, resistors 32 and 34 both have a value of 1 kΩ.",
"Trimming the pulse width of the gating signal of the upper switch 8 limits the open circuit voltage 4 .",
"However, during steady state operation, the voltage on the resistor 30 is very small, out of phase with the voltage on capacitor 16 , and still proportional to the lamp voltage 4 .",
"Hence, lamp voltage sensing is not affected by the resistor 30 when the ballast 2 is operating in the steady state.",
"The sampling circuit described above with respect to FIG. 2 can be used independently with or without a cable compensation circuit.",
"Since the voltage on resistor 30 is in phase with the current of the upper switch 8 , it is convenient to use the voltage on resistor 30 to control the open circuit voltage 4 when no lamp is connected and to trim the pulse width of the upper switch 8 of the half-bridge as discussed above.",
"However, when a long cable is connected and the capacitance of the cable is essentially in parallel with the resonant capacitor 14 , the parameters of the resonant tank constructed from inductor 12 and capacitor 14 changes.",
"As a result, the open circuit voltage 34 decreases when a cable is connected to the ballast 2 .",
"When the value of the resonant capacitor 14 is small, the decrease in the open circuit voltage 34 is significant and the ballast will not strike the lamp.",
"The open circuit voltage 4 can be set high to start a lamp with a long cable.",
"However, in applications where no cable is attached, the open circuit voltage 4 will then be too high, which may cause the ballast to fail the through-lamp leakage test, or damage the sampling film capacitor 16 .",
"Increasing the capacitance of the resonant capacitor 14 helps to decrease the variation of the open circuit voltage but increases the conduction losses due to the circulation currents in the resonant capacitor 14 .",
"Furthermore, larger capacitor values lead to saturation of the resonant inductor 12 .",
"Therefore, the most preferred embodiments of the present invention include a cable compensation circuits.",
"Capacitor sampling provides a strong sample signal with low output impedance and quick response.",
"A cable compensation circuit is created by adding zener diode 44 , resistors 42 and 46 , and capacitor 40 as shown in FIG. 3 .",
"The open circuit voltage 4 as sampled by capacitor 16 rises very rapidly at node 48 .",
"When the open circuit voltage 4 becomes too high, the zener diode 44 starts to conduct and feeds current to the base of transistor 36 such that the conductive threshold for the transistor 36 is decreased.",
"Thus, the transistor 36 starts to turn-on earlier when the voltage on resistor 30 is lower.",
"The pulse width of the gating signal of the upper switch 8 then becomes narrower thereby reducing the open circuit voltage 4 .",
"So, the true open circuit voltage 4 is sensed in this way to change the current threshold required to turn-off the switch 8 .",
"In an exemplary circuit constructed as described above, the open circuit voltage 4 varies from 1.9 kv to 2.6 kv without the cable compensation circuit of FIG. 3 when 18 feet of cable is connected to or removed from the circuit..",
"However, with the cable compensation circuit of FIG. 3 , the variation in the open circuit voltage 4 is within approximately 100V.",
"Thus, an electronic ballast having a lossless voltage sampling and control circuit and a cable compensation circuit in accordance with the preferred embodiment of the present invention as shown in FIG. 3 represents a substantial improvement upon the prior art.",
"Thus, although there have been described particular embodiments of the present invention of a new and useful Lossless Circuit for Sampling of Lamp Voltage, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims."
] |
FIELD OF THE INVENTION
This invention relates to medical devices and, more particularly, to a splash-shield and related fluid delivery device for providing effective irrigation while also preventing the splash of contaminated irrigating fluids onto administering personnel.
BACKGROUND OF THE INVENTION
Irrigation and lavage (referred to collectively as “irrigation”) are commonly used in medicine to cleanse areas of the body of microscopic and macroscopic foreign contamination. Such areas of the body shall be referred to herein as “compromised areas.” Such compromised areas include skin or wounds contaminated with infectious organisms, such as hepatitis virus, human immunodeficiency virus, or with biologically or chemically toxic matter. In such cases, medical personnel endeavor to remove the contaminant through copious irrigation, often with a saline solution. The fluid used to irrigate such compromised areas, the so-called “irrigant,” will generally become contaminated itself after contact with and irrigation of the infected area. If this contaminated irrigant contacts other, uninfected areas of the patient, there is a risk of further infection, which is obviously undesirable.
Accordingly, there is a need to drain or remove the contaminated irrigant from unnecessary further contact with the uninfected or uncompromised areas of the patient.
There is also a risk that the contaminated irrigant will contaminate the administering medical personnel. Syringes and needles are commonly used in a variety of configurations to provide irrigation. As such, the irrigant generally exits from a fluid delivery nozzle toward the compromised area under pressure, and if the fluid stream is not properly directed, controlled, or circumscribed, the contaminated irrigant will “splash back” onto, or otherwise make unintended contact with the administering personnel. This undesirable risk of being splashed with contaminated irrigant is all the more acute when copious amounts of irrigant are used or delivered under high pressure.
There is, accordingly, a further need to protect the administering personnel from undue exposure to contaminated irrigant splashing back from the compromised area or otherwise contacting such personnel.
The syringes and needles typically used in irrigation generally do not themselves protect either the patient or administering personnel from splash back of contaminated irrigant or undesired contact therewith. The current art has attempted to overcome this disadvantage, but such attempts have there own drawbacks and disadvantages, or have been generally ineffective.
For example, administering personnel often take universal or general precautions against contamination, such as impermeable gloves, clothing barriers, eye protection, and face-masks. To assure adequate protection from such general precautions, however, they are generally combined, in hopes of synergistically enhancing protection from contamination. This approach has the disadvantage not only of greater expense, but also greater inconvenience to the administering personnel, as well as excessive time spent in taking precautionary measures.
Moreover, the use of syringes or needles risks causing further injury to soft tissue structures, such as vessels, nerves, tendons, or other subcutaneous structures often found within a wound or other compromised area during the irrigation process. In the case of sharp needles attached to a syringe for purposes of irrigation, there is also the risk of delivering irrigant at excessive pressure and thereby further damaging the area. There is likewise the risk of puncture with a contaminated needle, either to the administering personnel or the patient.
One approach to solve the above-described drawbacks and disadvantages is to provide the syringe or other fluid delivery device with a shield to prevent undesired splash back of contaminated irrigant. An example of this approach is found in U.S. Pat. No. 4,769,003 (Stamler). The shield in Stamler is designed to be tilted in proximity to the area being treated to allow drainage. One of the drawbacks of this approach, however, is that the exiting fluid stream may become, under certain circumstances, difficult to direct as desired, or may not be adequately controlled or circumscribed by the disclosed structure. Under such circumstances, it is possible for both the patient and the administering personnel to come into unnecessary contact with contaminated irrigant.
Further examples of shields on fluid delivery devices are found in U.S. Pat. No. 5,735,833 (Olson); U.S. Pat. No. 5,030,214 (Spector); and U.S. Pat. No. 4,692,140 (Olson). These approaches, however, also suffer from various drawbacks and disadvantages. For example, irrigant may be dispersed inefficiently by the structures disclosed in these references. Further, the disclosed prior art devices can be cumbersome to use in certain situations, or may likewise be cost prohibitive. As such, these devices may not be well suited for applications requiring either portability of the device, or disposal after use.
A solution is thus needed which better balances the often competing interests associated with irrigation of compromised areas of the body.
It is desirable to balance the need to cleanse the compromised area quickly and effectively, with the need to protect both the patient and the medical personnel from unnecessary contact with the irrigant.
A device is needed which delivers irrigant at sufficient volume to cleanse the area, but not at such high pressure as to damage the area.
Notwithstanding the copious volume of irrigant which may be required, a device is needed to prevent the irrigant from splashing back onto the administering personnel, but in so doing, the device should also minimize the undesirable contact of contaminated irrigant with uncontaminated areas of the patient.
Still further, it is desirable for the device to be easy to use in emergency situations, and adaptable for use with various different syringes or still other fluid delivery devices.
SUMMARY
A medical device according to the present invention delivers irrigating fluid to a wound or other compromised area of a patient and includes a splash-shield for controlling (or “circumscribing”) the flow of the irrigant to minimize undesired contact with spent or contaminated irrigant, especially irrigant that splashes off of the area being irrigated. The structure of the splash-shield which circumscribes the flow of irrigant keeps the spent or contaminated irrigant away from not only the administrating personnel, but also the patient. A bell on the splash-shield has a proximal and a distal end, and the bell terminates in a rim with a rounded lip formed thereon. A fitting is formed at the proximal end of the bell, and the fitting is designed with a passage therein to receive the exit end of a fluid delivery device. The passage extends through the surface of the bell at an angle relative to the plane of the rim. At least one, preferably two bights are formed in the rim of the bell to define a corresponding drainage opening or openings.
In one version of the invention, the rim can be thought of as having a leading edge and a trailing edge opposite the leading edge. The passage exits at a location on the inner surface of the bell which is closer to the trailing edge than the leading edge, and the passage is oriented toward the leading edge. The drainage opening, in contrast, is located on the opposite leading edge. In this way, the fluid exiting the passage, although directed at the compromised area for irrigation purposes, also has a directional component toward the leading edge. This directional component toward the drainage openings is thought to improve the efficacy of irrigation and encourage drainage of spent irrigant through the drainage opening.
In accordance with another aspect of the invention, the bell has a radius increasing from the proximal end to the distal end, but with the radius at the leading edge increasing more rapidly than the radius at the trailing edge. As such, the bell encloses a volume in the shape of a half egg, and the rim encloses an elongated, ovate or egg-shaped perimeter.
The splash-shield, in accordance with other aspects of the invention, is removably received on the exit nozzle of any of a variety of delivery devices for the irrigant. Such delivery devices have a reservoir of fluid irrigant in hydraulic communication with the exit nozzle, and a suitable structure for expelling the fluid from the nozzle.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects of the invention are explained by the description below, in conjunction with the drawing, in which:
FIG. 1 is perspective view of a splash-shield according to the present invention, shown positioned over a compromised area of a patient's body to be irrigated;
FIG. 2 . is a front elevational view of the splash-shield of FIG. 1;
FIG. 3 is a side elevational view of the splash-shield of FIG. 1;
FIGS. 4 through 6 are rear, top, and bottom views of the splash-shield of FIG. 1;
FIGS. 7 through 11 are cross-sectional views of portable medical devices according to the present invention in combination with the splash-shield of FIGS. 1 - 6 .
DESCRIPTION
Referring now to the drawing, and in particular to FIGS. 1-6, thereof, a fluid delivery device 21 of the present invention comprises a splash-shield 23 with certain structural features which control the flow of irrigating fluid, thereby keeping spent or contaminated irrigating fluid from undesired contact with either the administering personnel or the patient. In this embodiment, splash-shield 23 is shown removably mounted to a connector 25 at the exit end of a fluid delivery device, such as those shown in FIGS. 7-11. In particular, connector 25 has a nozzle end 27 which extends through a passage 29 of the splash-shield 23 . The passage 29 is formed in a fitting 31 at proximal end 33 of splash-shield 23 . As schematically shown in FIG. 1 by dark headed arrows, irrigating fluid exits from nozzle end 27 and irrigates compromised area 35 which is enclosed by splash-shield 23 .
Passage 29 is oriented by an angle α, preferably about 15°, toward a pair of bights 34 , which serve as drainage openings. The angle α of passage 29 imparts a directional component to the exiting fluid toward bights 34 . Thus, although the irrigating fluid is directed toward compromised area 35 for purposes of irrigation, it also is directed toward the drainage openings. As shown in FIG. 1, splash-shield 23 is preferably positioned so that the drainage openings are downward from the compromised area 35 , allowing gravity to assist in draining spent or contaminated irrigant from compromised area 35 . Nonetheless, the directional component toward the drainage openings imparted by the angle α of passage 29 is also believed to encourage spent irrigant to leave the compromised area under treatment more efficiently, thereby reducing risk of either recontaminating irrigated areas or contaminating areas not under treatment. The structures of splash-shield 23 described above also allow administering personnel to better anticipate the flow of irrigant, so that such flow can be directed generally away from the administering personnel. In this way, the administering personnel are less likely to come into contact with irrigant as it drains from bights 34 .
Splash-shield 23 includes additional structural features which control or circumscribe flow of irrigant, especially in regard to splash back of irrigant, and which are believed to render irrigation more efficient. Splash-shield 23 includes a bell 37 which extends from proximal end 33 in increasing radius r (FIG. 3) to terminate in rim 39 at distal end 41 of bell 37 . Rim 39 defines an egg-shaped or ovate perimeter 43 , best seen in FIG. 6 .
Passage 29 extends between outer surface 47 of bell 37 and its inner surface 45 , so that fluid can be transmitted from outside the bell 37 to the compromised area 35 enclosed by inner surface 45 of bell 37 , as discussed above.
Rim 39 has a rounded lip 49 formed over substantially all its perimeter. The rounded lip has a radius sufficiently large, preferably about {fraction (3/64)}″, to reduce the risk of damaging the already compromised area 35 . For purposes of better understanding the present invention, rim 39 , which extends through a 360° arc, can be divided into a leading edge 51 and a trailing edge 53 at opposite ends of such 360° arc. It is to be understood that the terms “leading” or “trailing” are not intended to limit such rim locations to particular orientations or functions relative to the compromised area 35 , as such orientations or functions will vary depending on the particular compromised area 35 being treated, as well as the sound judgment of the administering personnel operating the splash-shield 23 . Passage 29 exits on inner surface 45 at a location closer to trailing edge 53 than leading edge 51 , as best seen in FIG. 6 .
Bell 37 is symmetrical about a longitudinal plane 55 (FIG. 2 ). Passage 29 lies in longitudinal plane 55 . The bights 34 are located on respective sides of longitudinal plane 55 , and rim 39 has sides 52 extending substantially in a single plane from trailing edge 53 to respective ones of the bights 34 .
Radius r of bell 37 increases more rapidly at arcuate locations corresponding to leading edge 51 than at corresponding locations of the trailing edge, with the result that bell 37 encloses a volume in the shape of a half egg. Rim 39 can be thought of as having a major longitudinal axis 57 which extends between leading edge 51 and trailing edge 53 , and a minor transverse axis 59 perpendicular to major axis 57 . Major axis 57 is longer than minor axis 59 , so that bell 37 is elongated in the dimension between the leading and trailing edges 51 , 53 , and the corresponding area of the body enclosed by bell 37 and subject to treatment is correspondingly lengthened and thereby enlarged.
The angle of passage 29 causes fluid to exit nozzle 27 not only downwardly toward compromised area 35 , but also in the elongated, longitudinal direction of bell 37 and toward the drainage openings. The lengthened area enclosed by rim 39 , the location of the passage 29 toward the trailing edge 53 , its angular orientation both toward the leading edge 55 and along the major, longitudinal axis, and the half-egg volume enclosed by bell 37 , are believed to efficiently distribute irrigant over the compromised area 35 enclosed by rim 39 , and are likewise believed to allow for efficient drainage of such irrigant through bights 34 .
In operation, of course, components of the fluid stream rebound from compromised area 35 not only toward the drainage openings, but in other random directions as well. The substantially planar sides 52 of rim 39 , and the coplanar trailing edge 53 , allow splash-shield 23 to be brought into substantial contact with the surface of the compromised area 35 during irrigation. The rounded lip 49 permits rim 39 to be brought into contact with, or close proximity to the area 35 being treated under most situations. The fluid rebounding in random directions is inhibited from exiting the volume enclosed by bell 37 by the contact of the planar sides 52 and trailing edge 53 with the surface of the area being treated. In this way, the administering personnel and the patient is spared undesired contact by spent irrigant.
Outer surface 47 has indicia located toward leading edge 51 along axis 57 for indicating the position of the fluid stream exiting passage 29 relative to the compromised area 35 . In this embodiment, such indicia comprise a raised region in the form of an arrow 61 . Outer surface 47 is also provided with means for assisting the administering personnel in placing his or her fingers on splash-shield 23 to hold bell 37 in position, such means here shown as a pair of protrusions 63 located on opposite sides of bell 37 between the leading and trailing edges 51 , 53 .
Splash-shield 23 is preferably molded from clear, polymeric material suitable for medical devices, to enable administering personnel to visualize the fluid stream with respect to the compromised area 35 . Although the exact dimensions of the structural features of the splash-shield 23 may be varied to suit different applications, in the preferred embodiment, the major, longitudinal axis 57 extends about 2 inches and the minor, transverse axis 59 is about 1.5 inches. Though the rim 39 lies preferably in a single plane with the exception of the bights 34 , the present invention is not limited thereto. The bights 34 are positioned at about 40° from the longitudinal plane and have radii of about 0.25 inches. The passage 29 exits on inner surface 45 of bell 37 at a height above rim 39 of between about 0.75 inches to about 1 inch. Passage 29 is tapered from a diameter of about {fraction (17/64)} of an inch to about {fraction (11/64)} of an inch, to enable friction fit of nozzle end 27 in a variety of forms as discussed below.
Referring now to FIGS. 7-11, a splash-shield is part of a medical device according to the present invention for irrigating compromised areas 35 . Such medical devices as shown in FIGS. 7-11 and described herein are preferably portable, suitable for irrigation under emergency department conditions, and include a reservoir of fluid irrigant, a fluid exit nozzle or tube, a splash shield mounted to such nozzle, and suitable structures to expel the fluid from the reservoir through the nozzle or exit end of the tube.
In one preferred embodiment shown in FIG. 7, a squeeze bottle 124 includes a delivery fitting 126 with one connector side mounted to a cap 130 of the bottle 124 and a second, opposite male connector 128 received in a friction fit into fitting 131 of bell 137 of splash-shield 123 , which splash-shield has the structural features described and shown in FIGS. 1-6. The delivery fitting 126 , bottle 124 , and cap 130 are further described in U.S. Pat. No. 5,795,324 issued to the same inventor, and the teachings of such disclosure are incorporated herein by reference.
A second embodiment of a fluid delivery device of the present invention is shown in FIG. 8, in which a syringe 224 has a blunt nose 226 received into fitting 231 of splash-shield 223 , which splash-shield has the structural features previously described and shown in FIGS. 1-6. FIG. 9 shows a further variation, in which an extension tube 330 is connected between the blunt nose 326 of syringe 324 and splash-shield 323 . This variation allows for more flexible placement of splash-shield 323 in relation to syringe 324 , as may be needed, for example, to treat compromised areas (not shown) which are less accessible or inconveniently located in relation to the administering personnel.
Still further embodiments of the present invention are shown in FIGS. 10 and 11. One end of delivery fitting 426 is a male-type connector adapted to “spike” into an IV bag 424 . The other end of delivery fitting 426 is a male-type connector adapted to frictionally insert into fitting 431 of splash-shield 423 in the case of FIG. 10, or into the appropriate end of extension tubing 430 in the case of FIG. 11 . The structure and use of delivery fitting 426 is further described in U.S. Pat. No. 5,931,820 issued to the same inventor, and its teachings are incorporated herein by reference.
Operation of the splash-shield and associated fluid delivery device is readily apparent from the foregoing description. A suitable configuration of fluid reservoir is selected, and an appropriate connector with or without extension tubing is interconnected between the fluid reservoir and the splash-shield. The administering personnel place the splash-shield against or very close to the compromised area to be treated. The splash-shield is preferably oriented so that drainage through bights 34 is gravity-assisted and, where possible, so that the flow of irrigant is away from the administering personnel. Fluid exiting splash shield 23 through bights 34 may be contained by absorbent material such as towels or collected by a suitable container. The portability of the device obviously allows the splash-shield to be applied in any orientation so as to substantially enclose the compromised area to be treated.
Once the splash-shield has been appropriately positioned, the administering personnel expels the fluid as appropriate to the particular situation, typically saline solution, by whatever means are appropriate to the fluid reservoir selected, namely, movement of a plunger in the case of a syringe, or squeezing the flexible sides of a squeeze bottle or IV bag.
In addition to the advantages apparent from the foregoing description, the fluid delivery device of the present invention accomplishes efficient irrigation or lavage, while at the same time minimizing undesired contact of the administering personnel or patient with spent or contaminated irrigant. In particular, the device minimizes “splashing” of the irrigant outside the treatment area.
The splash-shield can be advantageously placed against most compromised areas with less risk of further compromising the area.
As still another advantage, the irrigation device is cost effective and easy to operate quickly, such as may be required in emergency interventions.
The present invention has been described with reference to particular preferred embodiments. Such description is for purposes of setting out the best mode of practicing the invention for one skilled in the art, and is not intended to limit the invention to the particular instrumentalities disclosed. Still further variations to the described invention may be appreciated by those skilled in the art, or as skill or fancy may suggest, the invention thus being defined only by the appended claims and encompassing equivalent structures thereto. | A splash-shield and related fluid delivery device is intended for medical irrigation or lavage of compromised areas of skin. The device includes a passage for fluid to exit into a bell. The passage exits into the bell closer to one edge of the bell, but is angled toward the other end of the bell, where there are bights defining drainage openings. The angled passage imparts a directional component to the fluid stream which, along with any available gravity drainage, encourages the irrigant to flow over the compromised area and out of the bell. The splash-shield is egg-shaped to cover a larger compromised area and to further enhance the distribution of irrigant. The rim of the bell is shaped to discourage unintended splashing of spent irrigant onto the administering personnel or the patient, while nonetheless allowing for efficient irrigation. | Identify and summarize the most critical features from the given passage. | [
"FIELD OF THE INVENTION This invention relates to medical devices and, more particularly, to a splash-shield and related fluid delivery device for providing effective irrigation while also preventing the splash of contaminated irrigating fluids onto administering personnel.",
"BACKGROUND OF THE INVENTION Irrigation and lavage (referred to collectively as “irrigation”) are commonly used in medicine to cleanse areas of the body of microscopic and macroscopic foreign contamination.",
"Such areas of the body shall be referred to herein as “compromised areas.”",
"Such compromised areas include skin or wounds contaminated with infectious organisms, such as hepatitis virus, human immunodeficiency virus, or with biologically or chemically toxic matter.",
"In such cases, medical personnel endeavor to remove the contaminant through copious irrigation, often with a saline solution.",
"The fluid used to irrigate such compromised areas, the so-called “irrigant,” will generally become contaminated itself after contact with and irrigation of the infected area.",
"If this contaminated irrigant contacts other, uninfected areas of the patient, there is a risk of further infection, which is obviously undesirable.",
"Accordingly, there is a need to drain or remove the contaminated irrigant from unnecessary further contact with the uninfected or uncompromised areas of the patient.",
"There is also a risk that the contaminated irrigant will contaminate the administering medical personnel.",
"Syringes and needles are commonly used in a variety of configurations to provide irrigation.",
"As such, the irrigant generally exits from a fluid delivery nozzle toward the compromised area under pressure, and if the fluid stream is not properly directed, controlled, or circumscribed, the contaminated irrigant will “splash back”",
"onto, or otherwise make unintended contact with the administering personnel.",
"This undesirable risk of being splashed with contaminated irrigant is all the more acute when copious amounts of irrigant are used or delivered under high pressure.",
"There is, accordingly, a further need to protect the administering personnel from undue exposure to contaminated irrigant splashing back from the compromised area or otherwise contacting such personnel.",
"The syringes and needles typically used in irrigation generally do not themselves protect either the patient or administering personnel from splash back of contaminated irrigant or undesired contact therewith.",
"The current art has attempted to overcome this disadvantage, but such attempts have there own drawbacks and disadvantages, or have been generally ineffective.",
"For example, administering personnel often take universal or general precautions against contamination, such as impermeable gloves, clothing barriers, eye protection, and face-masks.",
"To assure adequate protection from such general precautions, however, they are generally combined, in hopes of synergistically enhancing protection from contamination.",
"This approach has the disadvantage not only of greater expense, but also greater inconvenience to the administering personnel, as well as excessive time spent in taking precautionary measures.",
"Moreover, the use of syringes or needles risks causing further injury to soft tissue structures, such as vessels, nerves, tendons, or other subcutaneous structures often found within a wound or other compromised area during the irrigation process.",
"In the case of sharp needles attached to a syringe for purposes of irrigation, there is also the risk of delivering irrigant at excessive pressure and thereby further damaging the area.",
"There is likewise the risk of puncture with a contaminated needle, either to the administering personnel or the patient.",
"One approach to solve the above-described drawbacks and disadvantages is to provide the syringe or other fluid delivery device with a shield to prevent undesired splash back of contaminated irrigant.",
"An example of this approach is found in U.S. Pat. No. 4,769,003 (Stamler).",
"The shield in Stamler is designed to be tilted in proximity to the area being treated to allow drainage.",
"One of the drawbacks of this approach, however, is that the exiting fluid stream may become, under certain circumstances, difficult to direct as desired, or may not be adequately controlled or circumscribed by the disclosed structure.",
"Under such circumstances, it is possible for both the patient and the administering personnel to come into unnecessary contact with contaminated irrigant.",
"Further examples of shields on fluid delivery devices are found in U.S. Pat. No. 5,735,833 (Olson);",
"U.S. Pat. No. 5,030,214 (Spector);",
"and U.S. Pat. No. 4,692,140 (Olson).",
"These approaches, however, also suffer from various drawbacks and disadvantages.",
"For example, irrigant may be dispersed inefficiently by the structures disclosed in these references.",
"Further, the disclosed prior art devices can be cumbersome to use in certain situations, or may likewise be cost prohibitive.",
"As such, these devices may not be well suited for applications requiring either portability of the device, or disposal after use.",
"A solution is thus needed which better balances the often competing interests associated with irrigation of compromised areas of the body.",
"It is desirable to balance the need to cleanse the compromised area quickly and effectively, with the need to protect both the patient and the medical personnel from unnecessary contact with the irrigant.",
"A device is needed which delivers irrigant at sufficient volume to cleanse the area, but not at such high pressure as to damage the area.",
"Notwithstanding the copious volume of irrigant which may be required, a device is needed to prevent the irrigant from splashing back onto the administering personnel, but in so doing, the device should also minimize the undesirable contact of contaminated irrigant with uncontaminated areas of the patient.",
"Still further, it is desirable for the device to be easy to use in emergency situations, and adaptable for use with various different syringes or still other fluid delivery devices.",
"SUMMARY A medical device according to the present invention delivers irrigating fluid to a wound or other compromised area of a patient and includes a splash-shield for controlling (or “circumscribing”) the flow of the irrigant to minimize undesired contact with spent or contaminated irrigant, especially irrigant that splashes off of the area being irrigated.",
"The structure of the splash-shield which circumscribes the flow of irrigant keeps the spent or contaminated irrigant away from not only the administrating personnel, but also the patient.",
"A bell on the splash-shield has a proximal and a distal end, and the bell terminates in a rim with a rounded lip formed thereon.",
"A fitting is formed at the proximal end of the bell, and the fitting is designed with a passage therein to receive the exit end of a fluid delivery device.",
"The passage extends through the surface of the bell at an angle relative to the plane of the rim.",
"At least one, preferably two bights are formed in the rim of the bell to define a corresponding drainage opening or openings.",
"In one version of the invention, the rim can be thought of as having a leading edge and a trailing edge opposite the leading edge.",
"The passage exits at a location on the inner surface of the bell which is closer to the trailing edge than the leading edge, and the passage is oriented toward the leading edge.",
"The drainage opening, in contrast, is located on the opposite leading edge.",
"In this way, the fluid exiting the passage, although directed at the compromised area for irrigation purposes, also has a directional component toward the leading edge.",
"This directional component toward the drainage openings is thought to improve the efficacy of irrigation and encourage drainage of spent irrigant through the drainage opening.",
"In accordance with another aspect of the invention, the bell has a radius increasing from the proximal end to the distal end, but with the radius at the leading edge increasing more rapidly than the radius at the trailing edge.",
"As such, the bell encloses a volume in the shape of a half egg, and the rim encloses an elongated, ovate or egg-shaped perimeter.",
"The splash-shield, in accordance with other aspects of the invention, is removably received on the exit nozzle of any of a variety of delivery devices for the irrigant.",
"Such delivery devices have a reservoir of fluid irrigant in hydraulic communication with the exit nozzle, and a suitable structure for expelling the fluid from the nozzle.",
"BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects of the invention are explained by the description below, in conjunction with the drawing, in which: FIG. 1 is perspective view of a splash-shield according to the present invention, shown positioned over a compromised area of a patient's body to be irrigated;",
"FIG. 2 .",
"is a front elevational view of the splash-shield of FIG. 1;",
"FIG. 3 is a side elevational view of the splash-shield of FIG. 1;",
"FIGS. 4 through 6 are rear, top, and bottom views of the splash-shield of FIG. 1;",
"FIGS. 7 through 11 are cross-sectional views of portable medical devices according to the present invention in combination with the splash-shield of FIGS. 1 - 6 .",
"DESCRIPTION Referring now to the drawing, and in particular to FIGS. 1-6, thereof, a fluid delivery device 21 of the present invention comprises a splash-shield 23 with certain structural features which control the flow of irrigating fluid, thereby keeping spent or contaminated irrigating fluid from undesired contact with either the administering personnel or the patient.",
"In this embodiment, splash-shield 23 is shown removably mounted to a connector 25 at the exit end of a fluid delivery device, such as those shown in FIGS. 7-11.",
"In particular, connector 25 has a nozzle end 27 which extends through a passage 29 of the splash-shield 23 .",
"The passage 29 is formed in a fitting 31 at proximal end 33 of splash-shield 23 .",
"As schematically shown in FIG. 1 by dark headed arrows, irrigating fluid exits from nozzle end 27 and irrigates compromised area 35 which is enclosed by splash-shield 23 .",
"Passage 29 is oriented by an angle α, preferably about 15°, toward a pair of bights 34 , which serve as drainage openings.",
"The angle α of passage 29 imparts a directional component to the exiting fluid toward bights 34 .",
"Thus, although the irrigating fluid is directed toward compromised area 35 for purposes of irrigation, it also is directed toward the drainage openings.",
"As shown in FIG. 1, splash-shield 23 is preferably positioned so that the drainage openings are downward from the compromised area 35 , allowing gravity to assist in draining spent or contaminated irrigant from compromised area 35 .",
"Nonetheless, the directional component toward the drainage openings imparted by the angle α of passage 29 is also believed to encourage spent irrigant to leave the compromised area under treatment more efficiently, thereby reducing risk of either recontaminating irrigated areas or contaminating areas not under treatment.",
"The structures of splash-shield 23 described above also allow administering personnel to better anticipate the flow of irrigant, so that such flow can be directed generally away from the administering personnel.",
"In this way, the administering personnel are less likely to come into contact with irrigant as it drains from bights 34 .",
"Splash-shield 23 includes additional structural features which control or circumscribe flow of irrigant, especially in regard to splash back of irrigant, and which are believed to render irrigation more efficient.",
"Splash-shield 23 includes a bell 37 which extends from proximal end 33 in increasing radius r (FIG.",
"3) to terminate in rim 39 at distal end 41 of bell 37 .",
"Rim 39 defines an egg-shaped or ovate perimeter 43 , best seen in FIG. 6 .",
"Passage 29 extends between outer surface 47 of bell 37 and its inner surface 45 , so that fluid can be transmitted from outside the bell 37 to the compromised area 35 enclosed by inner surface 45 of bell 37 , as discussed above.",
"Rim 39 has a rounded lip 49 formed over substantially all its perimeter.",
"The rounded lip has a radius sufficiently large, preferably about {fraction (3/64)}″, to reduce the risk of damaging the already compromised area 35 .",
"For purposes of better understanding the present invention, rim 39 , which extends through a 360° arc, can be divided into a leading edge 51 and a trailing edge 53 at opposite ends of such 360° arc.",
"It is to be understood that the terms “leading”",
"or “trailing”",
"are not intended to limit such rim locations to particular orientations or functions relative to the compromised area 35 , as such orientations or functions will vary depending on the particular compromised area 35 being treated, as well as the sound judgment of the administering personnel operating the splash-shield 23 .",
"Passage 29 exits on inner surface 45 at a location closer to trailing edge 53 than leading edge 51 , as best seen in FIG. 6 .",
"Bell 37 is symmetrical about a longitudinal plane 55 (FIG.",
"2 ).",
"Passage 29 lies in longitudinal plane 55 .",
"The bights 34 are located on respective sides of longitudinal plane 55 , and rim 39 has sides 52 extending substantially in a single plane from trailing edge 53 to respective ones of the bights 34 .",
"Radius r of bell 37 increases more rapidly at arcuate locations corresponding to leading edge 51 than at corresponding locations of the trailing edge, with the result that bell 37 encloses a volume in the shape of a half egg.",
"Rim 39 can be thought of as having a major longitudinal axis 57 which extends between leading edge 51 and trailing edge 53 , and a minor transverse axis 59 perpendicular to major axis 57 .",
"Major axis 57 is longer than minor axis 59 , so that bell 37 is elongated in the dimension between the leading and trailing edges 51 , 53 , and the corresponding area of the body enclosed by bell 37 and subject to treatment is correspondingly lengthened and thereby enlarged.",
"The angle of passage 29 causes fluid to exit nozzle 27 not only downwardly toward compromised area 35 , but also in the elongated, longitudinal direction of bell 37 and toward the drainage openings.",
"The lengthened area enclosed by rim 39 , the location of the passage 29 toward the trailing edge 53 , its angular orientation both toward the leading edge 55 and along the major, longitudinal axis, and the half-egg volume enclosed by bell 37 , are believed to efficiently distribute irrigant over the compromised area 35 enclosed by rim 39 , and are likewise believed to allow for efficient drainage of such irrigant through bights 34 .",
"In operation, of course, components of the fluid stream rebound from compromised area 35 not only toward the drainage openings, but in other random directions as well.",
"The substantially planar sides 52 of rim 39 , and the coplanar trailing edge 53 , allow splash-shield 23 to be brought into substantial contact with the surface of the compromised area 35 during irrigation.",
"The rounded lip 49 permits rim 39 to be brought into contact with, or close proximity to the area 35 being treated under most situations.",
"The fluid rebounding in random directions is inhibited from exiting the volume enclosed by bell 37 by the contact of the planar sides 52 and trailing edge 53 with the surface of the area being treated.",
"In this way, the administering personnel and the patient is spared undesired contact by spent irrigant.",
"Outer surface 47 has indicia located toward leading edge 51 along axis 57 for indicating the position of the fluid stream exiting passage 29 relative to the compromised area 35 .",
"In this embodiment, such indicia comprise a raised region in the form of an arrow 61 .",
"Outer surface 47 is also provided with means for assisting the administering personnel in placing his or her fingers on splash-shield 23 to hold bell 37 in position, such means here shown as a pair of protrusions 63 located on opposite sides of bell 37 between the leading and trailing edges 51 , 53 .",
"Splash-shield 23 is preferably molded from clear, polymeric material suitable for medical devices, to enable administering personnel to visualize the fluid stream with respect to the compromised area 35 .",
"Although the exact dimensions of the structural features of the splash-shield 23 may be varied to suit different applications, in the preferred embodiment, the major, longitudinal axis 57 extends about 2 inches and the minor, transverse axis 59 is about 1.5 inches.",
"Though the rim 39 lies preferably in a single plane with the exception of the bights 34 , the present invention is not limited thereto.",
"The bights 34 are positioned at about 40° from the longitudinal plane and have radii of about 0.25 inches.",
"The passage 29 exits on inner surface 45 of bell 37 at a height above rim 39 of between about 0.75 inches to about 1 inch.",
"Passage 29 is tapered from a diameter of about {fraction (17/64)} of an inch to about {fraction (11/64)} of an inch, to enable friction fit of nozzle end 27 in a variety of forms as discussed below.",
"Referring now to FIGS. 7-11, a splash-shield is part of a medical device according to the present invention for irrigating compromised areas 35 .",
"Such medical devices as shown in FIGS. 7-11 and described herein are preferably portable, suitable for irrigation under emergency department conditions, and include a reservoir of fluid irrigant, a fluid exit nozzle or tube, a splash shield mounted to such nozzle, and suitable structures to expel the fluid from the reservoir through the nozzle or exit end of the tube.",
"In one preferred embodiment shown in FIG. 7, a squeeze bottle 124 includes a delivery fitting 126 with one connector side mounted to a cap 130 of the bottle 124 and a second, opposite male connector 128 received in a friction fit into fitting 131 of bell 137 of splash-shield 123 , which splash-shield has the structural features described and shown in FIGS. 1-6.",
"The delivery fitting 126 , bottle 124 , and cap 130 are further described in U.S. Pat. No. 5,795,324 issued to the same inventor, and the teachings of such disclosure are incorporated herein by reference.",
"A second embodiment of a fluid delivery device of the present invention is shown in FIG. 8, in which a syringe 224 has a blunt nose 226 received into fitting 231 of splash-shield 223 , which splash-shield has the structural features previously described and shown in FIGS. 1-6.",
"FIG. 9 shows a further variation, in which an extension tube 330 is connected between the blunt nose 326 of syringe 324 and splash-shield 323 .",
"This variation allows for more flexible placement of splash-shield 323 in relation to syringe 324 , as may be needed, for example, to treat compromised areas (not shown) which are less accessible or inconveniently located in relation to the administering personnel.",
"Still further embodiments of the present invention are shown in FIGS. 10 and 11.",
"One end of delivery fitting 426 is a male-type connector adapted to “spike”",
"into an IV bag 424 .",
"The other end of delivery fitting 426 is a male-type connector adapted to frictionally insert into fitting 431 of splash-shield 423 in the case of FIG. 10, or into the appropriate end of extension tubing 430 in the case of FIG. 11 .",
"The structure and use of delivery fitting 426 is further described in U.S. Pat. No. 5,931,820 issued to the same inventor, and its teachings are incorporated herein by reference.",
"Operation of the splash-shield and associated fluid delivery device is readily apparent from the foregoing description.",
"A suitable configuration of fluid reservoir is selected, and an appropriate connector with or without extension tubing is interconnected between the fluid reservoir and the splash-shield.",
"The administering personnel place the splash-shield against or very close to the compromised area to be treated.",
"The splash-shield is preferably oriented so that drainage through bights 34 is gravity-assisted and, where possible, so that the flow of irrigant is away from the administering personnel.",
"Fluid exiting splash shield 23 through bights 34 may be contained by absorbent material such as towels or collected by a suitable container.",
"The portability of the device obviously allows the splash-shield to be applied in any orientation so as to substantially enclose the compromised area to be treated.",
"Once the splash-shield has been appropriately positioned, the administering personnel expels the fluid as appropriate to the particular situation, typically saline solution, by whatever means are appropriate to the fluid reservoir selected, namely, movement of a plunger in the case of a syringe, or squeezing the flexible sides of a squeeze bottle or IV bag.",
"In addition to the advantages apparent from the foregoing description, the fluid delivery device of the present invention accomplishes efficient irrigation or lavage, while at the same time minimizing undesired contact of the administering personnel or patient with spent or contaminated irrigant.",
"In particular, the device minimizes “splashing”",
"of the irrigant outside the treatment area.",
"The splash-shield can be advantageously placed against most compromised areas with less risk of further compromising the area.",
"As still another advantage, the irrigation device is cost effective and easy to operate quickly, such as may be required in emergency interventions.",
"The present invention has been described with reference to particular preferred embodiments.",
"Such description is for purposes of setting out the best mode of practicing the invention for one skilled in the art, and is not intended to limit the invention to the particular instrumentalities disclosed.",
"Still further variations to the described invention may be appreciated by those skilled in the art, or as skill or fancy may suggest, the invention thus being defined only by the appended claims and encompassing equivalent structures thereto."
] |
CROSS-REFERENCE TO RELATED U.S. PATENT APPLICATIONS
This application is a Continuation of U.S. application Ser. No. 09/854,975 filed May 14, 2001, now U.S. Pat. No. 6,762,125 issued Jul. 13, 2004, hereby incorporated herein by reference.
FIELD OF THE INVENTION
This invention relates to semiconductor manufacture, and more particularly to facet etching useful for improving subsequent dielectric layer step coverage.
BACKGROUND OF THE INVENTION
A major goal of any dielectric deposition system is good step coverage. Step coverage refers to the ability of subsequent layers to evenly cover layers (“steps”) already present on the substrate. Facet etches are frequently used to provide superior step coverage. The standard facet etch uses a high energy argon ion which physically bombards the material being etched and thereby etches the oxide at an angle to allow subsequent material to have the best step coverage possible. However, if the argon ions etch through the oxide and reach metal or another conductor, they disperse their energy into the metal line or other conductor. This energy finds its way to a ground through a weak spot in the gate oxide thereby resulting in a blown gate.
In sputter etching, ions which impinge on horizontal surfaces have a minimal effect on etch rate and profile. However, the sputter yield of the etch at the corners is approximately four times that of the etch rate of a horizontal surface, thereby creating an extreme etch profile. The effect is the wearing away of the corners of a feature at approximately 45 degree angles. The material removed by the sputter etch is redeposited along the sides of the feature and along the surface of the substrate.
An issue associated with sputter etching is that some of the sputtered material redeposits frequently on the inside surfaces of the etching chamber. This redeposited material must be removed at intervals, thereby taking the etching chamber off-line.
SUMMARY OF THE INVENTION
The process of the present invention employs a two-step etching sequence wherein an insulating layer deposited on top of a plurality of conductive structures is first etched by a high energy inert gas ion to physically sputter the oxide material and form a faceted etch. The first step etch is terminated prior to reaching a predetermined target depth. The second step etch is conducted with a reactant gas to further remove the insulating material down to the target depth.
In a preferred embodiment, the method of the invention comprises forming a first layer comprising an insulating material superjacent a substrate comprising a plurality of conductive structures, at least some of the conductive structures being placed apart to form spaces between the conductive structures, such that the first layer forms in at least some of the spaces between the conductive structures and the first layer is formed to a thickness at least equal to the target depth. Next, the first layer is etched by directing a plasma of an inert gas at the first layer formed in at least some of the spaces between the conductive structures. The plasma is of sufficient energy to sputter material from the first layer thereby forming a facet etch in the first layer formed in the spaces between the conductive structures. The first etch is terminated when the first layer has been etched to a predetermined depth which is less than the target depth. Next, the first layer is etched, in a second etch, by contacting the first layer with a reactive chemical gas/plasma. The second etch is terminated when the first layer has been etched to the target depth.
Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are described below with reference to the following accompanying drawings, which are for illustrative purposes only. Throughout the following views, reference numerals will be used in the drawings, and the same reference numerals will be used throughout the several views and in the description to indicate same or like parts.
FIG. 1 is a schematic view of a semiconductor device having a plurality of conductive structures.
FIG. 2 is a schematic view of the semiconductor device of FIG. 1 at a later stage in the process.
FIG. 3 shows a schematic view of a portion of the semiconductor device of FIG. 2 .
FIG. 4 shows the semiconductor device of FIG. 2 at a later stage in the process.
FIG. 5 shows a portion of the semiconductor device of FIG. 4 .
FIG. 6 shows the semiconductor device of FIG. 4 at a later stage of the process.
DETAILED DESCRIPTION OF THE INVENTION
In the following detailed description, references made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural, logical and electrical changes may be made without departing from the spirit and scope of the present invention.
FIG. 1 shows a semiconductor device 1 suitable for use in a preferred embodiment of this invention. The semiconductor device 1 comprises a plurality of conductive structures 12 overlying a substrate 10 . The conductive structures 12 are positioned in close proximity to each other to form spaces 14 between the conductive structures 12 .
Conductive structures 12 can be any conductive element of semiconductor device 1 but are typically metal lines, runners, leads or interconnects. Conductive structures 12 typically comprise at least one of titanium, tungsten, tantalum, molybdenum, aluminum, copper, gold, silver, nitrides thereof and silicides thereof.
The substrate 10 includes any semiconductor-based structure having a silicon base. The base of substrate 10 is to be understood as including silicon-on-insulator (SOI) or silicon-on-sapphire (SOS) technology, doped and undoped semiconductors, epitaxial layers of silicon supported by a base semiconductor foundation, and other semiconductor structures. Furthermore, previous process steps may have been used to form regions or junctions in the base semiconductor structure or foundation. Typically, the substrate 10 will comprise at least one layer of material deposited on top of the silicon base. In one preferred embodiment, the uppermost layer of material of substrate 10 , which contacts conductive structures 12 , will be a dielectric material such as silicon dioxide or boron phosphosilicate glass (BPSG).
A first layer 16 is formed over the substrate 10 and conductive structures 12 as shown in FIG. 2 . First layer 16 comprises a dielectric material 17 , preferably silicon dioxide or BPSG. First layer 16 may be conveniently formed by chemical vapor deposition or any other suitable means.
As shown in FIG. 3 , the spaces 14 between the conductive structures 12 are not completely or uniformly filled during the formation of first layer 16 . In particular, the bottom 37 and lower corners 36 of space 14 are covered with a thinner depth of dielectric material 17 than are the sidewalls 38 and upper corners 35 . This nonuniform coverage of dielectric material 17 leads to the formation of undesirable voids, known as keyholes within the first layer 16 or between the first layer 16 and subsequent layers.
A facet etch is performed to provide a lower aspect opening for subsequent layers as shown in FIG. 4 . The facet etch is conveniently performed by placing the semiconductor device 1 in a high vacuum reactor on a cathode for which a power source creates a radio frequency (RF) of 13.56 Mhz, while controlling the introduction of the etchant gases.
The walls of the reactor are grounded to allow for a return RF path. This chamber configuration is generally referred to as a Reactive Ion Etcher (R.I.E.). The RF power source acts to create a plasma condition within the chamber, thereby allowing for the creation of charged particles or ions 40 .
Due to the physics of the RF powered electrode, a direct current self-bias voltage condition is created at the semiconductor device 1 location. This self-bias condition acts to direct the charged particles or ions 40 toward the semiconductor device 1 in a direction perpendicular to the device surface 1 .
If the pressure is in a range being slightly less than 30 mtorr, the mean free path of the charged particles or ions 40 will be great enough to allow for physical sputtering of dielectric material 17 when the ions 40 impinge on the surface of the first layer 16 . It is important to note that a wide variety of systems and parameters can be used to effect a facet etch, as long as the pressure limit is not violated. As the pressure nears and exceeds 30 mtorr, the results of the process are effected.
Typical parameters for facet etching using an Applied Materials 5000 Series equipment are as follows:
RF power: 300-700 watts
pressure: 10-30 mtorr
etchant: 30-70 sccm.
The facet etch is performed for a time sufficient to obtain holes with sloping sides 42 in first layer 16 as shown in FIG. 4 . The facet etch is terminated at depth 51 prior to removing the dielectric material 17 to a predetermined target depth 53 as shown in FIG. 5 . The facet etch is terminated at a depth at least half of the target depth. For example, if the target depth is 300 Å, the facet etch will be at least 150 Å. Preferably, the facet etch is as deep as possible, as constrained by the possibility of etching through first layer 16 , in order to allow the second etch to maintain the facet contour. Typically, the facet etch is terminated less than about 150 Å, preferably no more than about 100 Å, more preferably, not more than about 50 Å prior to the target depth 53 . Some of the sputtered dielectric material 17 redeposits 55 in bottom corners 36
Subsequent to the termination of the facet etch, a chemical reactive ion etch (RIE) is performed on first layer 16 . The RIE is a directional etch which removes dielectric material 17 along the profile established by the facet etch. The RIE is terminated when sufficient dielectric material 17 is removed to reach the target depth 53 . This two-stage etch therefore results in a profiled etch of the desired depth.
As shown in FIG. 6 , a second layer 64 may then be formed over first layer 16 with the formation of only minimized keyholes 66 . Additionally, the upper surface 68 of the second layer is relatively even.
As is typical with any sputter process, some of the sputtered dielectric material redeposits onto the interior surfaces of the etching chamber. The sputtered material which redeposits onto the chamber surfaces gradually builds up to a depth sufficient to impair the operation of the etching chamber. At that time, the etching chamber must be taken off-line for cleaning and reconditioning. An additional benefit to the current two-stage process is that the second stage reactive ion etch also etches the material building up on the chamber surfaces. As such, the etching chamber is at least partially cleaned on-line and the time between off-line cleaning and reconditioning is greatly extended.
In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents. | A modified facet etch is disclosed to prevent blown gate oxide and increase etch chamber life. The modified facet etch is a two-stage process. The first stage is a plasma sputter etch to form a facet profile. The first stage etch is terminated prior to reaching the target depth for the etching process. The second stage etch is a reactive ion etch which directionally follows the facet profile to reach the target depth. | Summarize the information, clearly outlining the challenges and proposed solutions. | [
"CROSS-REFERENCE TO RELATED U.S. PATENT APPLICATIONS This application is a Continuation of U.S. application Ser.",
"No. 09/854,975 filed May 14, 2001, now U.S. Pat. No. 6,762,125 issued Jul. 13, 2004, hereby incorporated herein by reference.",
"FIELD OF THE INVENTION This invention relates to semiconductor manufacture, and more particularly to facet etching useful for improving subsequent dielectric layer step coverage.",
"BACKGROUND OF THE INVENTION A major goal of any dielectric deposition system is good step coverage.",
"Step coverage refers to the ability of subsequent layers to evenly cover layers (“steps”) already present on the substrate.",
"Facet etches are frequently used to provide superior step coverage.",
"The standard facet etch uses a high energy argon ion which physically bombards the material being etched and thereby etches the oxide at an angle to allow subsequent material to have the best step coverage possible.",
"However, if the argon ions etch through the oxide and reach metal or another conductor, they disperse their energy into the metal line or other conductor.",
"This energy finds its way to a ground through a weak spot in the gate oxide thereby resulting in a blown gate.",
"In sputter etching, ions which impinge on horizontal surfaces have a minimal effect on etch rate and profile.",
"However, the sputter yield of the etch at the corners is approximately four times that of the etch rate of a horizontal surface, thereby creating an extreme etch profile.",
"The effect is the wearing away of the corners of a feature at approximately 45 degree angles.",
"The material removed by the sputter etch is redeposited along the sides of the feature and along the surface of the substrate.",
"An issue associated with sputter etching is that some of the sputtered material redeposits frequently on the inside surfaces of the etching chamber.",
"This redeposited material must be removed at intervals, thereby taking the etching chamber off-line.",
"SUMMARY OF THE INVENTION The process of the present invention employs a two-step etching sequence wherein an insulating layer deposited on top of a plurality of conductive structures is first etched by a high energy inert gas ion to physically sputter the oxide material and form a faceted etch.",
"The first step etch is terminated prior to reaching a predetermined target depth.",
"The second step etch is conducted with a reactant gas to further remove the insulating material down to the target depth.",
"In a preferred embodiment, the method of the invention comprises forming a first layer comprising an insulating material superjacent a substrate comprising a plurality of conductive structures, at least some of the conductive structures being placed apart to form spaces between the conductive structures, such that the first layer forms in at least some of the spaces between the conductive structures and the first layer is formed to a thickness at least equal to the target depth.",
"Next, the first layer is etched by directing a plasma of an inert gas at the first layer formed in at least some of the spaces between the conductive structures.",
"The plasma is of sufficient energy to sputter material from the first layer thereby forming a facet etch in the first layer formed in the spaces between the conductive structures.",
"The first etch is terminated when the first layer has been etched to a predetermined depth which is less than the target depth.",
"Next, the first layer is etched, in a second etch, by contacting the first layer with a reactive chemical gas/plasma.",
"The second etch is terminated when the first layer has been etched to the target depth.",
"Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings.",
"BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are described below with reference to the following accompanying drawings, which are for illustrative purposes only.",
"Throughout the following views, reference numerals will be used in the drawings, and the same reference numerals will be used throughout the several views and in the description to indicate same or like parts.",
"FIG. 1 is a schematic view of a semiconductor device having a plurality of conductive structures.",
"FIG. 2 is a schematic view of the semiconductor device of FIG. 1 at a later stage in the process.",
"FIG. 3 shows a schematic view of a portion of the semiconductor device of FIG. 2 .",
"FIG. 4 shows the semiconductor device of FIG. 2 at a later stage in the process.",
"FIG. 5 shows a portion of the semiconductor device of FIG. 4 .",
"FIG. 6 shows the semiconductor device of FIG. 4 at a later stage of the process.",
"DETAILED DESCRIPTION OF THE INVENTION In the following detailed description, references made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced.",
"These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural, logical and electrical changes may be made without departing from the spirit and scope of the present invention.",
"FIG. 1 shows a semiconductor device 1 suitable for use in a preferred embodiment of this invention.",
"The semiconductor device 1 comprises a plurality of conductive structures 12 overlying a substrate 10 .",
"The conductive structures 12 are positioned in close proximity to each other to form spaces 14 between the conductive structures 12 .",
"Conductive structures 12 can be any conductive element of semiconductor device 1 but are typically metal lines, runners, leads or interconnects.",
"Conductive structures 12 typically comprise at least one of titanium, tungsten, tantalum, molybdenum, aluminum, copper, gold, silver, nitrides thereof and silicides thereof.",
"The substrate 10 includes any semiconductor-based structure having a silicon base.",
"The base of substrate 10 is to be understood as including silicon-on-insulator (SOI) or silicon-on-sapphire (SOS) technology, doped and undoped semiconductors, epitaxial layers of silicon supported by a base semiconductor foundation, and other semiconductor structures.",
"Furthermore, previous process steps may have been used to form regions or junctions in the base semiconductor structure or foundation.",
"Typically, the substrate 10 will comprise at least one layer of material deposited on top of the silicon base.",
"In one preferred embodiment, the uppermost layer of material of substrate 10 , which contacts conductive structures 12 , will be a dielectric material such as silicon dioxide or boron phosphosilicate glass (BPSG).",
"A first layer 16 is formed over the substrate 10 and conductive structures 12 as shown in FIG. 2 .",
"First layer 16 comprises a dielectric material 17 , preferably silicon dioxide or BPSG.",
"First layer 16 may be conveniently formed by chemical vapor deposition or any other suitable means.",
"As shown in FIG. 3 , the spaces 14 between the conductive structures 12 are not completely or uniformly filled during the formation of first layer 16 .",
"In particular, the bottom 37 and lower corners 36 of space 14 are covered with a thinner depth of dielectric material 17 than are the sidewalls 38 and upper corners 35 .",
"This nonuniform coverage of dielectric material 17 leads to the formation of undesirable voids, known as keyholes within the first layer 16 or between the first layer 16 and subsequent layers.",
"A facet etch is performed to provide a lower aspect opening for subsequent layers as shown in FIG. 4 .",
"The facet etch is conveniently performed by placing the semiconductor device 1 in a high vacuum reactor on a cathode for which a power source creates a radio frequency (RF) of 13.56 Mhz, while controlling the introduction of the etchant gases.",
"The walls of the reactor are grounded to allow for a return RF path.",
"This chamber configuration is generally referred to as a Reactive Ion Etcher (R.I.E.).",
"The RF power source acts to create a plasma condition within the chamber, thereby allowing for the creation of charged particles or ions 40 .",
"Due to the physics of the RF powered electrode, a direct current self-bias voltage condition is created at the semiconductor device 1 location.",
"This self-bias condition acts to direct the charged particles or ions 40 toward the semiconductor device 1 in a direction perpendicular to the device surface 1 .",
"If the pressure is in a range being slightly less than 30 mtorr, the mean free path of the charged particles or ions 40 will be great enough to allow for physical sputtering of dielectric material 17 when the ions 40 impinge on the surface of the first layer 16 .",
"It is important to note that a wide variety of systems and parameters can be used to effect a facet etch, as long as the pressure limit is not violated.",
"As the pressure nears and exceeds 30 mtorr, the results of the process are effected.",
"Typical parameters for facet etching using an Applied Materials 5000 Series equipment are as follows: RF power: 300-700 watts pressure: 10-30 mtorr etchant: 30-70 sccm.",
"The facet etch is performed for a time sufficient to obtain holes with sloping sides 42 in first layer 16 as shown in FIG. 4 .",
"The facet etch is terminated at depth 51 prior to removing the dielectric material 17 to a predetermined target depth 53 as shown in FIG. 5 .",
"The facet etch is terminated at a depth at least half of the target depth.",
"For example, if the target depth is 300 Å, the facet etch will be at least 150 Å.",
"Preferably, the facet etch is as deep as possible, as constrained by the possibility of etching through first layer 16 , in order to allow the second etch to maintain the facet contour.",
"Typically, the facet etch is terminated less than about 150 Å, preferably no more than about 100 Å, more preferably, not more than about 50 Å prior to the target depth 53 .",
"Some of the sputtered dielectric material 17 redeposits 55 in bottom corners 36 Subsequent to the termination of the facet etch, a chemical reactive ion etch (RIE) is performed on first layer 16 .",
"The RIE is a directional etch which removes dielectric material 17 along the profile established by the facet etch.",
"The RIE is terminated when sufficient dielectric material 17 is removed to reach the target depth 53 .",
"This two-stage etch therefore results in a profiled etch of the desired depth.",
"As shown in FIG. 6 , a second layer 64 may then be formed over first layer 16 with the formation of only minimized keyholes 66 .",
"Additionally, the upper surface 68 of the second layer is relatively even.",
"As is typical with any sputter process, some of the sputtered dielectric material redeposits onto the interior surfaces of the etching chamber.",
"The sputtered material which redeposits onto the chamber surfaces gradually builds up to a depth sufficient to impair the operation of the etching chamber.",
"At that time, the etching chamber must be taken off-line for cleaning and reconditioning.",
"An additional benefit to the current two-stage process is that the second stage reactive ion etch also etches the material building up on the chamber surfaces.",
"As such, the etching chamber is at least partially cleaned on-line and the time between off-line cleaning and reconditioning is greatly extended.",
"In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features.",
"It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect.",
"The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents."
] |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a gene implicated in abiotic stress tolerance and growth promotion and a method for improving abiotic stress tolerance and promoting growing of transformed plants with the same.
[0003] 2. Description of the Related Art
[0004] Due to their sessile nature, higher plants are constantly faced with various adverse environmental factors, including drought, high salt, heavy metals, cold, heat shock, and ozone, during their whole life span. These abiotic stresses are a limiting factor for the growth and development of crop plants. Water deficiency causes dramatic reduction of crop production globally, and the decreasing availability of fresh water may pose a future threat to humans and higher plants. Plants have diverse defense strategies to enhance their tolerance to transient and long-term water shortages by triggering signaling network pathways and inducing stress-responsive genes. The cellular and genetic defense mechanisms in response to water stress have been widely documented (Shinozaki and Yamaguchi-Shinozaki, 2007). However, for stress tolerance or sensitivity, our knowledge concerning the biological functions of stress-related genes in higher plants is still rudimentary. Therefore, it is important to study the functions of stress responsive genes to increase the productivity and distribution of crop plants.
[0005] Ubiquitin is a protein consisting of 76 amino acids and it has been found in almost all tissues of eukaryotic organisms. Ubiquitin has a characteristic that is covalently bound to various substrate proteins by E1-E2-E3 consecutive actions of ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s) and ubiquitin ligases (E3s). The substrate proteins to be attached with ubiquitin are very diverse, affecting almost all physiological activities. In addition, many studies have been found that the many diseases are associated with these mechanisms. A function of ubiquitin is firstly known to promote degradation of protein by attaching with other proteins. However, other functions of ubiquitin have been recently revealed one after another.
[0006] Ubiquitin is attached to substrate by consecutive actions of three types of proteins, i.e., E1, E2 and E3. The glycine residue at the C-terminal domain of ubiquitin binds to NH 3 at R— group of lysine residues on the substrate protein, thereby forming a covalent bond with the substrate. In general, proteins attached with ubiquitin are degraded by proteasome. Polyubiquitin as a chain of several ubiquitin molecules has to be attached to the substrate for degradation by proteasome. Until now, it has been known that proteasome-dependent degradation of the substrate occurs only when polyubiquitin consisting of at least four ubiquitins is attached to the substrate; however, it would be controversial since these results were obtained from in vitro experiments. Polyubiquitination leading to the proteasome-dependent degradation is the linkage form in which the 48 th lysine residue of one ubiquitin is linked to another ubiquitin.
[0007] There are 2 types of E1 enzymes in organism. There are various types of E2s. In general, E2s catalyse the transfer of ubiquitin from E1 to E3 or substrate. E3s which are also known as E3 ligases catalyse the final step of the ubiquitination cascade. E3s determine specificity of the substrate to be ubiquitinated. In other words, the substrate being capable of interaction with certain E3s is specifically determined. E3 enzymes may be classified into two major types according to domains. E3 enzymes possess one of two domains: the homologous to the E6-AP carboxyl terminus (HECT) domain and the really interesting new gene (RING) domain. E3 enzymes having RING domain serves to position E2 and substrate in close proximity each other. In other words, where E2 and the substrate bind to E3, distance between ubiquitin of E2 and the substrate is formed to close sufficiently such that ubiquitin of E2 is chemically passed to the substrate. In contrast, E3 enzymes having HECT domain receive ubiquitin from E2, and then transfer it to the substrate. The At5g01520 gene codes for the protein having E3 ubiquitin ligase enzymatic activity. The ubiquitination has been known to serve diverse functions as one of the mechanism that all higher organisms as well as plants have. However, the genes involved in abiotic stresses have been unknown. The present inventors have isolated the At5g01520 genes in which the expression is induced by abiotic stresses and ABA hormone in Arabidopsis thaliana . Then, they have prepared At5g01520s-overexpresors and knock-out mutants and analyzed their physiological phenotypes.
[0008] Throughout this application, various publications and patents are referred and citations are provided in parentheses. The disclosures of these publications and patents in their entities are hereby incorporated by references into this application in order to fully describe this invention and the state of the art to which this invention pertains.
SUMMARY OF THE INVENTION
[0009] The present inventors have made intensive studies to improve a tolerance to abiotic stresses of a plant. As results, they have discovered that a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2 was involved in the above-mentioned characteristic of the plant. In addition, where the gene expression was inhibited, transgenic plants having the improved tolerance to abiotic stresses may be obtained.
[0010] Accordingly, it is an object of this invention to provide a composition for improving the tolerance of a plant to an abiotic stress, and a plant cell or a plant exhibiting improved tolerance to an abiotic stress, transformed with the composition.
[0011] It is another object of this invention to provide a composition for promoting germination of a plant.
[0012] Other objects and advantages of the present invention will become apparent from the following detailed description together with the appended claims and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIGS. 1 a - d represent results of analyzing the AtAIRP2 gene expression by RT-PCR after treatments of various abiotic stresses and ABA hormone. After treatments of ABA hormone ( FIG. 1 a ), drought stress ( FIG. 1 b ), low-temperature stress ( FIG. 1 c ) and salt stress ( FIG. 1 d ), each RNA was extracted to analyze the gene expression pattern. RD29A was used as a representative control gene in treatments of drought, salt and low-temperature, and RAB18 was used as a representative control gene in treatment of ABA.
[0014] FIG. 2 represents results of analyzing the promoter activity of the AtAIRP2 gene by GUS assay. When 100 μM ABA (3 hours) or drought (2 hours) condition was treated, GUS signals were markedly induced. It could be determined that promoter activity of the AtAIRP2 gene was increased.
[0015] FIG. 3 represents results of analyzing the enzymatic activity of the AtAIRP2 protein. Maltose-binding protein (MBP) was bound to the AtAIRP2 proteins. Then, MBP-AtAIRP2 was incubated with HIS-UBA1, HIS-UBC8, ubiquitin and AtAIRP2 at 30° C. for 1 hour to perform Self-Ubiquitination, and performed by Western blot using MBP- and ubiquitin-specific antibodies to analyze changes in the protein levels. As a result, it was determined that the molecular weight of the AtAIRP2 protein was increased through Western blot using anti-MBP antibody, and the increase was induced due to ubiquitin. Based on the results, it could be demonstrated that the AtAIRP2 protein possessed ability for enzymatic activity of E3 ubiquitin ligase that binds ubiquitin protein.
[0016] FIGS. 4 a - d represent results of measuring the AtAIRP2 gene mutants and their tolerance to drought stress. FIG. 4 a represents the gene map that the T-DNAs were inserted to the exon (AtAIRP2-1) and the intron (AtAIRP2-2) in genomic DNA of the AtAIRP2 gene. FIG. 4 b represents that T-DNA insertions were verified by PCR amplification using the T-DNA border primer and primers annealing to sites upstream and downstream of the T-DNA insertion site with the extracted genomic DNA from the knock-out mutant. FIG. 4 c represents that the expression of the gene was analyzed by RT-PCR with the extracted RNA from the knock-out mutant. Based on the results, it could be demonstrated that the expression of the gene in the AtAIRP2 mutant was inhibited. FIG. 4 d represents images of comparing the tolerance to drought stress in the AtAIRP2 gene mutants and the wild type Arabidopsis thaliana . Each of plants was grown for 2 weeks, and subjected to drought stress by withholding water for 13 days, respectively. The plants were then re-watered and monitored the number of the survived plant. As a result, mutants were less tolerant to drought stress than the wild types ( FIG. 4 d ).
[0017] FIGS. 5 a - b represent results of the AtAIRP2-overexpressing transgenic plants. Arabidopsis thaliana was transformed by 355:AtAIRP2-GFP recombinant vector and it was verified whether to overexpress the gene using anti-GFP antibody ( FIG. 5 a ). As a result of Western blot, it could be demonstrated that the AtAIRP2-GFP protein was well-expressed. FIG. 5 b represents images of comparing the tolerance to drought stress in the AtAIRP2-overexpressing transgenic and the wild type Arabidopsis thaliana . Each of plants was grown for 2 weeks, and subjected to drought stress by withholding water for 14 days, respectively. The plants were then re-watered and monitored the number of the survived plant. As a result, the AtAIRP2-overexpressing transgenic plants were more tolerant to drought stress than the wild types.
[0018] FIGS. 6 a - b represent results of analyzing germination rates according to ABA hormone in the AtAIRP2 knock-out mutant and the AtAIRP2-overexpressing transgenic plant. FIG. 6 a represents images of the wild type, the AtAIRP2-1 mutant and the AtAIRP2-2 mutant which were grown on medium supplemented with different concentrations (0.1 and 0.5 μM) of ABA hormone for 7 days. It could be understood that the germination rates of mutants which were grown on medium supplemented with ABA hormone were higher than that of the wild types. FIG. 6 b represents images of the wild type, the AtAIRP2-2 mutant and the AtAIRP2-sGFP overexpressing transgenic plant which were grown on medium supplemented with different concentrations (0.2 and 0.4 μM) of ABA hormone for 7 days. It could be understood that the germination rates of the AtAIRP2 overexpressing transgenic plants which were grown on medium supplemented with ABA hormone were significantly inhibited. In addition, it could be demonstrated that the AtAIRP2-2 mutant showed the tolerant under the same condition. Therefore, it could be understood that the germination rates in the AtAIRP2-overexpressing transgenic plants were decreased by ABA hormone and the germination rate in mutant was increased by ABA hormone.
DETAILED DESCRIPTION OF THE INVENTION
[0019] In one aspect of this invention, there is provided a composition for improving the tolerance of a plant to an abiotic stress, comprising a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2.
[0020] The present inventors have made intensive studies to improve a tolerance to abiotic stresses of a plant. As results, they have discovered that a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2 was involved in the above-mentioned characteristic of the plant. In addition, where the gene expression was inhibited, transgenic plants having the improved tolerance to abiotic stresses may be obtained.
[0021] According to a preferred embodiment, the present nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2 comprises the nucleotide sequence as set forth in SEQ ID NO:1. According to the present invention, the nucleotide sequence as set forth in SEQ ID NO:1 is the nucleotide sequence of the At5g01520 gene in Arabidopsis thaliana , and the gene is named as the AtAIRP2 ( Arabidopsis thaliana ABA Insensitive Ring Protein 2). The gene encodes RING protein having E3 ubiquitin ligase enzymatic activity. The present inventors have found that expressions of the gene were increased by various abiotic stresses and ABA hormone.
[0022] It would be obvious to the skilled artisan that the nucleotide sequences used in this invention are not limited to those listed in the appended Sequence Listings.
[0023] For nucleotides, the variations may be purely genetic, i.e., ones that do not result in changes in the protein product. This includes nucleic acids that contain functionally equivalent codons, or codons that encode the same amino acid, such as six codons for arginine or serine, or codons that encode biologically equivalent amino acids.
[0024] Considering biologically equivalent variations described hereinabove, the nucleic acid molecule of this invention may encompass sequences having substantial identity to them. Sequences having the substantial identity show at least 80%, more preferably at least 90%, most preferably at least 95% similarity to the nucleic add molecule of this invention, as measured using one of the sequence comparison algorithms. Methods of alignment of sequences for comparison are well-known in the art. Various programs and alignment algorithms are described in: Smith and Waterman, Adv. Appl. Math. 2:482(1981); Needleman and Wunsch, J. Mol. Bio. 48:443(1970); Pearson and Lipman, Methods in Mol. Biol. 24: 307-31(1988); Higgins and Sharp, Gene 73:237-44(1988); Higgins and Sharp, CABIOS 5:151-3(1989) Corpet et al., Nuc. Acids Res. 16:10881-90(1988) Huang et al., Comp. Appl. BioSci. 8:155-65(1992) and Pearson et al., Meth. Mol. Biol. 24:307-31(1994). The NCBI Basic Local Alignment Search Tool (BLAST) [Altschul et al., J. Mol. Biol. 215:403-10(1990)] is available from several sources, including the National Center for Biological Information (NBCI, Bethesda, Md.) and on the Internet, for use in connection with the sequence analysis programs blastp, blasm, blastx, tblastn and tblastx. It can be accessed at http://www.ncbi.nlm.nih.gov/BLAST/. A description of how to determine sequence identity using this program is available at http://www.ncbi.nlm.nih.gov/BLAST/blast_help.html.
[0025] According to a preferred embodiment, the present abiotic stress is selected from the group consisting of a drought stress, a low-temperature stress and a salt stress.
[0026] According to the present invention, the present inventors have demonstrated that expressions of the At5g01520 gene were increased when plants were subjected to drought stress, low-temperature stress or salt stress. In addition, they have demonstrated that the tolerances to these stresses were improved when the gene was over-expressed in plants.
[0027] More preferably, the present abiotic stress is drought stress.
[0028] In another aspect of this invention, there is provided a composition for improving a tolerance of a plant to an abiotic stress, comprising a recombinant plant expression vector which comprises: (a) the nucleotide sequence as disclosed in the present invention; (b) a promoter which is operatively linked to the nucleotide sequence of (a) and generates a RNA molecule in plant cells; and (c) a poly A signal sequence inducing polyadenylation at the 3′-end of the RNA molecule.
[0029] The term “operatively linked” as used herein refers to functional linkage between a nucleic acid expression control sequence (such as a promoter, signal sequence, or array of transcription factor binding sites) and a second nucleotide sequence, wherein the expression control sequence affects transcription and/or translation of the nucleic acid corresponding to the second sequence.
[0030] The vector system of this invention may be constructed in accordance with conventional techniques described in Sambrook et al., Molecular Cloning, A Laboratory Manual , Cold Spring Harbor Laboratory Press (2001), teachings of which are incorporated herein by reference.
[0031] The suitable promoter in the present invention includes any one commonly used in the art, for example SP6 promoter, T7 promoter, T3 promoter, PM promoter, maize-ubiquitin promoter, Cauliflower mosaic virus (CaMV)-35S promoter, Nopalin synthase (nos) promoter, Figwort mosaic virus 35S promoter, Sugarcane bacilliform virus promoter, commelina yellow mottle virus promoter, photo-inducible promoter of small subunit of Ribulose-1,5-bis-phosphate carboxylase (ssRUBISCO), cytosolic triosphosphate isomerase (TPI) promoter in rice, adenine phosphoribosyltransferase (APRT) or octopine synthase promoter in Arabidopsis . Preferably, the promoter used in this invention is CaMV 35S.
[0032] According to a preferred embodiment, the poly A signal sequence inducing polyadenylation at the 3′-end includes that from the nopaline synthase gene of Agrobacterium tumefaciens (NOS 3′ end) (Bevan et al., Nucleic Acids Research, 11(2):369-385(1983)), that from the octopine synthase gene of Agrobacterium tumefaciens , the 3′-end of the protease inhibitor I or II genes from potato or tomato, the CaMV 35S terminator, and OCS (octopine synthase) terminator. Most preferably, the poly A signal sequence inducing polyadenylation at the 3′-end in this invention is OCS (octopine synthase) terminator.
[0033] Optionally, the present vector for plants may further carry a reporter molecule (e.g., genes for luciferase and β-glucuronidase). In addition, the vector may contain antibiotic resistant genes as selective markers (e.g., neomycin phosphotransferase gene (nptII) and hygromycin phosphotransferase gene (hpt)).
[0034] According to a preferred embodiment, the plant expression vector of this invention is Agrobacterium binary vectors.
[0035] The term “binary vector” as used herein, refers to a cloning vector containing two separate vector systems harboring one plasmid responsible for migration consisting of left border (LB) and right border (RB), and another plasmid for target gene-transferring. Any Agrobacterium suitable for expressing the nucleotide of this invention may be used, and most preferably, the transformation is carried out using Agrobacterium tumefaciens GV3101.
[0036] Introduction of the recombinant vector of this invention into Agrobacterium can be carried out by a large number of methods known to one skilled in the art. For example, particle bombardment, electroporation, transfection, lithium acetate method and heat shock method may be used. Preferably, the electroporation is used.
[0037] In still another aspect of this invention, there is provided a plant cell exhibiting improved tolerance to an abiotic stress, transformed with the composition of this invention.
[0038] In further aspect of this invention, there is provided a plant exhibiting improved tolerance to an abiotic stress, transformed with the composition of this invention.
[0039] To introduce a foreign nucleotide sequence into plant cells or plants may be performed by the methods ( Methods of Enzymology , Vol. 153 (1987)) known to those skilled in the art. The plant may be transformed using the foreign nucleotide inserted into a carrier (e.g., vectors such as plasmid or virus) or Agrobacterium tumefaciens as a mediator (Chilton et al., Cell, 11:263:271 (1977)) and by directly inserting the foreign nucleotide into plant cells (Lorz et al., Mol. Genet., 199: 178-182 (1985); the disclosure is herein incorporated by reference). For example, electroporation, microparticle bombardment, polyethylene glycol-mediated uptake may be used in the vector containing no T-DNA region.
[0040] Generally, Agrobacterium -mediated transformation is the most preferable (U.S. Pat. Nos. 5,004,863, 5,349,124 and 5,416,011), and the skilled artisan can incubate or culture the transformed cells or seeds to mature plants in appropriate conditions.
[0041] The term “plant(s)” as used herein, is understood by a meaning including a plant cell, a plant tissue and a plant seed as well as a mature plant.
[0042] The plants applicable of the present invention include, but not limited to, food crops such as rice plant, wheat, barley, corn, bean, potato, Indian bean, oat and Indian millet; vegetable crops such as Arabidopsis sp., Chinese cabbage, radish, red pepper, strawberry, tomato, watermelon, cucumber, cabbage, melon, pumpkin, welsh onion, onion and carrot; crops for special use such as ginseng , tobacco plant, cotton plant, sesame, sugar cane, sugar beet, Perilla sp., peanut and rape; fruit trees such as apple tree, pear tree, jujube tree, peach tree, kiwi fruit tree, grape tree, citrus fruit tree, persimmon tree, plum tree, apricot tree and banana tree; flowering crops such as rose, gladiolus, gerbera , carnation, chrysanthemum , lily and tulip; and fodder crops such as ryegrass, red clover, orchardgrass, alfalfa, tallfescue and perennial ryograss.
[0043] In still further aspect of this invention, there is provided a composition for promoting germination of a plant comprising a nucleic acid molecule, wherein nucleic acid molecule inhibits an expression of a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2.
[0044] According to a preferred embodiment, the present nucleotide sequence comprises the nucleotide sequence as set forth in SEQ ID NO:1.
[0045] According to the present invention, the nucleotide sequence as set forth in SEQ ID NO:1 is the nucleotide sequence of the At5g01520 gene. According to the present invention, it was determined that Where expressions of the present nucleotide sequence were inhibited, the sensitivity to ABA hormone suppressing immature-germination was decreased such that the germination rates were increased. Therefore, the present nucleic acid molecule enables to store seeds for a long time with excellent germination rates.
[0046] According to a preferred embodiment, the nucleic acid molecule is T-DNA, siRNA, shRNA, miRNA, ribozyme, PNA (peptide nucleic acids) or antisense oligonucleotide. More preferably, the present nucleic acid molecule is T-DNA.
[0047] The term “siRNA” used herein refers to a short double strand RNA that enables to mediate RNA interference via cleavage of mRNA. The siRNA of the present invention may consist of a sense RNA strand having a sequence corresponding to a target gene and an antisense RNA strand having a sequence complementary to the target gene. The siRNA to inhibit expression of a target gene provides effective gene knock-down method or gene therapy method.
[0048] The siRNA of this invention is not restricted to a RNA duplex of which two strands are completely paired and may comprise non-paired portion such as mismatched portion with non-complementary bases and bulge with no opposite bases. The overall length of the siRNA is 10-100 nucleotides, preferably 15-80 nucleotides, and more preferably, 20-70 nucleotides. The siRNA may comprise either blunt or cohesive end so long as it enables to inhibit the target gene expression via RNAi effect. The cohesive end may be prepared in 3′-end overhanging structure or 5′-end overhanging structure. The base number protruded is not particularly limited, for example 1-8 bases, preferably 2-6 bases. In addition, siRNA may comprise low molecular weight RNA (for example, tRNA, rRNA, natural RNA molecule such as viral RNA or artificial RNA molecule) in the protruded portion of one end to the extent that it enables to maintain an effect on the inhibition of target gene expression. The terminal structure of siRNA is not demanded as cut structure at both ends, and one end portion of double strand RNA may be stem-and-loop structure linked by a linker RNA. The length of linker is not restricted where it has no influence on the pair formation of the stem portion.
[0049] The term “shRNA” used herein refers to a single strand nucleotide consisting of 50-70 bases, and forms stem-loop structure in vivo. Long RNA of 19-29 nucleotides is complementarily base-paired at both directions of loop consisting of 5-10 nucleotides, forming a double-stranded stem.
[0050] The term “miRNA (microRNA)” functions to regulate gene expression and means a single strand RNA molecule composed of 20-50 nucleotides in full-length, preferably 20-45 nucleotides, more preferably 20-40 nucleotides, much more preferably 20-30 nucleotides and most preferably, 21-23 nucleotides. The miRNA is an oligonucleotide which is not expressed intracellularly, and forms a short stem-loop structure. The miRNA has a whole or partial complementarity to one or two or more mRNAs (messenger RNAs), and the target gene expression is suppressed by the complementary binding of miRNA to the mRNA thereof.
[0051] The term used herein “ribozyme” refers to a RNA molecule having an activity of an enzyme in itself which recognizes and restricts a base sequence of a specific RNA. The ribozyme consists of a binding portion capable of specifically binding a base sequence complementary to a transfer RNA strand and an enzymatic portion to cut target RNA.
[0052] The term “PNA (peptide nucleic acid)” used herein refers to a molecule having the characteristics of both nucleic acid and protein, which is capable of complementarily binding to DNA or RNA. PNA was first reported in 1999 as similar DNA in which nucleobases are linked via a peptide bond (Nielsen P E, Egholm M, Berg R H, Buchardt O, “Sequence-selective recognition of DNA by strand displacement with a thymine-substituted polyamide”, Science 1991, Vol. 254: pp 1497-1500). PNA is absent in the natural world and artificially synthesized through a chemical method. PNA is reacted with a natural nucleic acid having a complementary base sequence through hybridization response, forming double strand. In the double strand with the same length, PNA/DNA and PNA/RNA double strand are more stable than DNA/DNA and DNA/RNA double strand, respectively. The form of repeating N-(2-aminoethyl)-glycine units linked by amide bonds is commonly used as a basic peptide backbone. In this context, the backbone of peptide nucleic acid is electrically neutral in comparison to that of natural nucleic acids having negative charge. Four bases of nucleic acid present in PNA are almost the same to those of natural nucleic acid in the respect of spatial size and distance between nucleobases. PNA has not only a chemical stability compared with natural nucleic acid, but also a biological stability due to no degradation by a nuclease or protease.
[0053] The term “antisense oligonucleotide” used herein is intended to refer to nucleic acids, preferably, DNA, RNA or its derivatives, that are complementary to the base sequences of a target mRNA, characterized in that they bind to the target mRNA and interfere its translation to protein. The antisense oligonucleotide of the present invention refers to DNA or RNA sequences which are complementary to a target mRNA, characterized in that they bind to the target mRNA and interfere its translation to protein, translocation into cytoplasm, maturation or essential activities to other biological functions. The length of antisense nucleic acids is in a range of 6-100 nucleotides and preferably 10-40 nucleotides.
[0054] The antisense oligonucleotides may be modified at above one or more positions of base, sugar or backbone to enhance their functions [De Mesmaeker, et al., Curr Opin Struct Biol., 5(3): 343-55 (1995)]. The oligonucleotide backbone may be modified with phosphothioate, phosphotriester, methyl phosphonate, single chain alkyl, cycloalkyl, single chain heteroatomic, heterocyclic bond between sugars, and so on. In addition, the antisense nucleic acids may include one or more substituted sugar moieties. The antisense oligonucleotides may include a modified base. The modified base includes hypoxanthine, 6-methyladenine, 5-me pyrimidine (particularly, 5-methylcytosine), 5-hydroxymethylcytosine (HMC), glycosyl HMC, gentobiosyl HMC, 2-aminoadenine, 2-thiouracil, 2-thiothymine, 5-bromouracil, 5-hydroxymethyluracil, 8-azaguanine, 7-deazaguanine, N6(6-aminohexyl)adenine, 2,6-diaminopurine, and so forth.
[0055] The term “T-DNA” used herein refers to a DNA fragment as a transfer DNA in Ti (tumor-inducing) plasmid of Agrobacterium sp., which is transferred into a nucleus of a host plant cell. A 25 bp repeat sequence is present in both termini of T-DNA, and DNA transfer proceeds at the direction from a left border to a right border. A bacterial T-DNA with about 20,000 in length destroys a target gene by insertion, resulting in insertional muatagenesis. In addition to mutation, inserted T-DNA sequence may label a target gene. According to the present invention, the present inventors have used seeds of Arabidopsis thaliana for suppressing the expression of the At5g01520 gene by means of Ti-plasmid transformation.
[0056] In still further aspect of this invention, there is provided a composition for promoting germination of a plant, comprising a recombinant plant expression vector which comprises: (a) the nucleotide sequence as disclosed in the present invention; (b) a promoter which is operatively linked to the nucleotide sequence of (a) and generates a RNA molecule in plant cells; and (c) a poly A signal sequence inducing polyadenylation at the 3′-end of the RNA molecule.
[0057] Since the nucleic acid molecule, the plant expression recombinant vector and the introduction method thereof are mentioned above, they are omitted herein to avoid excessive overlaps.
[0058] The features and advantages of the present invention will be summarized as follows:
[0059] (a) The present invention provides a composition for improving the tolerance of a plant to an abiotic stress and a composition for promoting germinating of a plant.
[0060] (b) The present nucleotide sequence is involved in tolerance to drought stress of plants. Therefore, the overexpressing transgenic plants have excellent tolerances to various abiotic stresses including drought stress, whereby they may be useful as novel functional crops which are affected by climates and environments of the cultivated areas.
[0061] (c) In addition, the present nucleotide sequence is involved in sensitivity to ABA hormone of plants. Therefore, germination abilities of the knock-out mutant plants in which the expression is inhibited are remarkably enhanced, whereby they may effectively used for cultivating the plants with novel function of storage period increasing, and biomass.
[0062] The present invention will now be described in further detail by examples. It would be obvious to those skilled in the art that these examples are intended to be more concretely illustrative and the scope of the present invention as set forth in the appended claims is not limited to or by the examples.
EXAMPLES
Experimental Methods
Isolation of the Genes
[0063] The present inventors have isolated the AtAIRP2 genes inducible by ABA hormone and abiotic stresses from cDNAs of Arabidopsis thaliana. 10-day-old Arabidopsis thaliana seedlings were grinded with liquid nitrogen in mortar. The powders were added with 2 ml of an extraction buffer (4 M guanidine-HCl 20 mM, 10 mM EDTA, 10 mM EGTA (USB), 0.5% Sarkosyl (SIGMA), pH 9) and β-mercaptoethanol (SIGMA-ALDRICH) per 1 g of the powder for extraction. The extraction resultant was transferred to new conical tube, suspended with an equal volume of PCI (phenol:chloroform:isoamyl alcohol=25:24:1), vortexed for 5 min and centrifuged at 3,500 rpm for 25 min (Hanil centrifuge, HA-1000-3). After centrifugation, the upper organic solvent phase was removed. The extract was resuspended with an equal volume of PCI, vortexed and centrifuged twice. Then, the lower aqueous phase was undergone twice ethanol precipitation and once LiCl precipitation to isolate RNA. RNA was quantified. Single-strand cDNA was synthesized by using 2 μg of RNA with oligo dT primer and MMLV reverse transcriptase (Fermentas). PCR was conducted in the final volume of 50 μL containing 20 ng of cDNA as a template, 10 pmole of each of two types of primers, 5 μL of 10× Taq polymerase buffer (Takara), 8 μL of dNTPs (each of 1.25 mM) and 1 unit of Taq DNA polymerase (Takara). The tube containing the reaction mixture was placed in Perkin Elmer DNA thermal cycler. The sequences of primers used in this Example are as follows: 5′-ATGCGAAAATCGTTCAAGGA-3′ (AtAIRP2 ORF FW: SEQ ID NO: 3) and 5′-TCACCGAGGAAGAGGAGCATAA-3′ (AtAIRP2 ORF RV: SEQ ID NO: 41). The reaction mixture was denatured for 2 min at 94° C. and subjected to 30 cycles of 30 sec at 94° C., 30 sec at 52° C. and 1 min at 72° C. After 30 cycles, polymerization was further performed at 72° C. for 5 min. Then, the AtAIRP2 gene amplification was verified by using electrophoresis method. In addition, the DNA was confirmed by sequencing.
Plant Growth Conditions and Sampling
[0064] In order to prepare the AtAIRP2-overexpressing transgenic plants, Invitrogen gateway system was used to construct. First, AtAIRP1-sGFP was introduced into pENTR SD Topo vector (Invitrogen, USA) and subsequently integrated into pEarlygate 100 vector ( Arabidopsis research center, USA) of plants using LR clonase enzyme (Invitrogen).
[0065] Seeds of the AtAIRP2 knock-out mutants (seed number: SAIL_686_G08 (AtAIRP2-1), Salk_005082 (AtAIRP2-2)) which are T-DNA insertion lines were purchased from SIGNAL Salk Institute Genomic Analysis Laboratory (http://signal.salk.edu/).
[0066] The seeds of the AtAIRP2-overexpressing transgenic plants, knock-out mutants and the wild type Arabidopsis thaliana were soaked in 30% bleach solution (Yuhanclorox) and 0.025% Triton X-100 for 10 min, and washed 10 times with sterilized water. The treated seeds were grown on MS (Murashige and Skoog) medium (Duchefa Biochemie) that contained 3% sucrose, B5 vitamin (12 mg/L) and 0.8% agar (pH 5.7) in a growth chamber for 2 weeks (under a condition of 16 hrs-light/8 hrs-dark cycle). Where green whole plants of light condition were used as materials, seeds were grown on soil of Sunshine MIX #5 (Sun GroHorticulture) in a growth chamber for 3 weeks (under a condition of 16 hrs-light/8 hrs-dark cycle).
Treatments of Stresses (Salt, Low-Temperature, Drought and ABA Hormone)
[0067] In order to determine expressions of the AtAIRP2 gene to drought stress, the wild type Arabidopsis thaliana seedlings which were grown on medium for 2 weeks were exposed in the air, and sampled after 1 hour and 2 hours. In order to determine expressions of the AtAIRP2 gene to salt stress, the wild type Arabidopsis thaliana seedlings which were grown on medium for 2 weeks were treated with 300 mM sodium chloride, and sampled after 1.5 hour and 3 hours. In order to determine expressions of the AtAIRP2 gene to low-temperature stress, the wild type Arabidopsis thaliana seedlings which were grown on medium for 2 weeks were incubated at 4° C. for 12 hours and 24 hours, and sampled. In order to determine expressions of the AtAIRP2 gene to ABA hormone stress, the wild type Arabidopsis thaliana seedlings which were grown on medium for 2 weeks were treated with 100 μM of ABA (SIGMA), and sampled after 1.5 hour and 3 hours. The sampled tissues were grinded with liquid nitrogen in mortar. The powders were added with β-mercaptoethanol (SIGMA-ALDRICH) and 2 ml of an extraction buffer (4 M guanidine-HCl 20 mM, 10 mM EDTA, 10 mM EGTA (USB), 0.5% Sarkosyl (SIGMA), pH 9) per 1 g of the powder to extract. The extract was transferred to new conical tube, suspended with an equal volume of PCI (phenol:chloroform:isoamyl alcohol=25:24:1), vortexed for 5 min and centrifuged at 3,500 rpm for 25 min (Hanil centrifuge, HA-1000-3). After centrifugation, the supernatant which is upper organic solvent phase was removed. The extract was resuspended with an equal volume of PCI, vortexed and centrifuged. The extract was performed twice with the process described above. Then, the lower aqueous phase was performed twice with ethanol precipitation and once with LiCl precipitation to isolate RNA.
Quantitative Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)
[0068] Total RNA was isolated from leaves of the AtAIRP2-overexpressing transgenic plants, knock-out mutants and the wild type Arabidopsis thaliana . Single-strand cDNA was synthesized by using 2 μg of RNA with oligo dT primer and MMLV reverse transcriptase (Fermentas). PCR was conducted in the final volume of 50 μL containing 20 ng of cDNA as a template, 10 pmole of each of two types of primers, 5 μL of 10× Taq polymerase buffer (Intron), 8 μL of dNTPs (each of 1.25 mM) and 1 unit of Taq DNA polymerase (Intron). The tube containing the reaction mixture was placed in Perkin Elmer DNA thermal cycler. The reaction mixture was denatured for 2 min at 94° C. and subjected to 25 cycles of 30 sec at 94° C., 30 sec at 52° C. and 1 min at 72° C. After 25 cycles, polymerization was further performed at 72° C. for 5 min. Then, the PCR products were stored at −20° C. in a freezer. The sequences of primers used in this Example are shown in Table 1.
[0000] TABLE 1 Primers used in RT-PCR Primer sequence AtAIRP2 RT FW 5′-GATGGTGGCTACGTTCAGA-3′ (SEQ ID: 5) AtAIRP2 RT RV 5′-AAATGTCAATAACCAATGGTTG-3′ (SEQ ID: 6) Rab18 FW 5′-GCGTCTTACCAGAACCGTCC-3′ (SEQ ID: 7) Rab18 RV 5′-CCCTTCTTCTCGTGGTGC-3′ (SEQ ID: 8) RD29a FW 5′-CAGGTGAATCAGGAGTTGTT-3′ (SEQ ID: 9) RD29a RV 5′-CCGGAAATTTATCCTCTTCT-3′ (SEQ ID: 10) UBC10 FW 5′-TGGATATGGCGTCGAAGC-3′ (SEQ ID: 11) UBC10 RV 5′-GTGGGATTTTCCATTTAGCC-3′ (SEQ ID: 12)
Extraction of Genomic DNA of Mutants Inserted with T-DNA and Acquisition of Homozygous Mutant
[0069] The seeds of the wild type Arabidopsis thaliana and knock-out mutants were grown on soil for 2 weeks and their leave were sampled. The leaves were grinded with liquid nitrogen in mortar. The powders were added with 700 mL of CTAB buffer (2% CTAB, 100 mM Tris pH 8, 20 mM EDTA, 1.4 M NaCl, 2% PVP), mixed and heated at 65° C. for 10 min. The resultants were added to 200 mL of chloroform, mixed and centrifuged. After centrifugation, the supernatant was removed. The resultant was mixed with isopropanol to precipitate DNA. The precipitate was washed with 70% ethanol, dried. The obtained genomic DNA was dissolved in water to use. Genotyping PCR was performed using T-DNA border primer (LB_6313R) and primers annealing to sites upstream and downstream of the T-DNA insertion site.
[0000]
TABLE 2
Primers used in Genotyping PCR and RT-PCR
Primer
Sequence
LB_6313R
5′-GAGCTGCTATACACTGATCTGAG-3′
(SEQ ID: 13)
AtAIRP2 FW1
5′-CGTGTGCTCTACGCGAATC-3′
(SEQ ID: 14)
AtAIRP2 RV1
5′-CCCTTAATCAGCAAATATGATATCG-3′
(SEQ ID: 15)
[0070] It was revealed that the T-DNA insertions were mapped to the second exon and the first intron in the AtAIRP2 gene knock-out mutant, which was verified by PCR amplification using the T-DNA border primer and primers annealing to sites upstream and downstream of the T-DNA insertion site ( FIG. 4 b ). In addition, the suppression of the gene expression was analyzed by RT-PCR using AtAIRP2 FW1 and AtAIRP2 RV1 primers with the extracted RNA from the knock-out mutant ( FIG. 4 c ).
Preparation of Vector Construct of the AtAIRP2 Gene
[0071] For construction of a recombinant plasmid for expressing the fusion protein between the AtAIRP2 and maltose-binding protein (MBP), PCR was carried out using a primer set designed to contain XbaI and PstI restriction sites linked to 5′-direction and 3′-direction of the coding region of the AtAIRP2 gene, respectively. PCR products and pMAL-X vector (New England Biolabs, Beverly, Mass.) were restricted by XbaI and PstI restriction enzymes and then ligated using T4 DNA ligase (New England Bio Lab). The recombinant MBP-AtAIRP2 was expressed in Escherichia coli strain BL21-CodonPlus (DE3) RIL (Stratagene) and purified using amylose column chromatography. The protein was quantified using BSA as a standard protein. In addition, in the present invention, Invitrogen gateway system was used to construct for preparing transgenic plants. First, AtAIRP2-sGFP was introduced into pENTR SD Topo vector (Invitrogen, USA) and subsequently integrated into pEarlygate 100 vector ( Arabidopsis research center, USA) of plants using LR clonase enzyme (Invitrogen).
[0000] AtAIRP2 Transformation with Agrobacterium tumefaciens Strain and Preparation of the AtAIRP2 Transgenic Plants
[0072] The prepared constructs were transferred to Agrobacterium tumefaciens strain GV3101 by electroporation. The presence of the gene was confirmed by PCR. An aerial part of approximately 4-week-old Arabidopsis thaliana (columbia [Col-0]) was soaked on MS medium (Duchefa Biochemie) containing 0.05% Silwet for 1.5 min to transform (clough and Bent, 1998, Plant J 16; 735-743). The seedlings were grown for 3 weeks in a 23° C.-growth chamber to obtain seeds (T1). The transformed seeds (T1) were selected from medium containing 25 μg/mL of BASTA (Glufosinate ammonium) and 250 μg/mL of carbenicillin. The presence of the transgene was verified by RT-PCR and western blot. Overexpression of the transgene was observed using anti-GFP antibody (clontech).
Analysis on Enzymatic Activity of the AtAIRP2 Protein
[0073] For the enzymatic activity analysis of the AtAIRP2 protein, the ORF of the AtAIRP2 gene was subcloned into pMAL-X vector in-frame with MBP (maltose-binding protein). 40 mM Tris-HCl, pH 7.5, 5 mM MgCl2, 2 mM ATP, 2 mM dithiothreitol (DTT), 300 ng/μL ubiquitin (Sigma), 25 μM MG132 (A.G. Scientific Inc.), 500 ng UBA1 (ABRC, http://www.arabidopsis.org), 500 ng UBC8 (ABRC, http://www.arabidopsis.org) and 500 ng MBP-AtAIRP2 were added to each of tubes and incubated at 30° C. After addition of sample buffer solution, the resultant was heated at 100° C. for 5 min, and performed by Western blot using anti-MBP (New England Bio Labs) and anti-ubiquitin (Santa Cruz) antibodies.
Comparison of Plant Growth
[0074] For comparing phenotypes to ABA hormone, seeds obtained from the wild type, the AtAIRP2 knock-out mutant and the AtAIRP2-overexpressing transgenic plant were grown on medium supplemented with different concentrations (0, 0.2, 0.4 and 0.5 μM) of ABA hormone for 7 days, and their germination degrees were then measured. In order to compare phenotypes to salt, seeds obtained from the wild type, the AtAIRP2 knock-out mutant and the AtAIRP2-overexpressing transgenic plant were grown on medium supplemented with different concentrations (0, 0.2, 0.4 and 0.5 μM) of sodium chloride for 7 days, and their germination degrees were then measured.
Measurement of Sensitivity of Adult Plants to Drought Stress
[0075] Seeds obtained from the wild type, the AtAIRP2 knock-out mutant and the AtAIRP2-overexpressing transgenic plant were grown on soil for 2 weeks, and subjected to drought stress by withholding water for 13 or 14 days, respectively. The plants were then re-watered and measured the degrees of the tolerance to drought stress.
Histochemical GUS Assay
[0076] The wild type Arabidopsis thaliana was grown on medium for 10 days, subjected to 100 mM of ABA hormone and drought stress, and fixed with 90% acetone for 5 min. After removal of the acetone, the plant was washed 3 times with rincing solution containing 50 mM NaPO 4 , 1 mM K 3 Fe(CN) 6 , and 1 mM K 4 Fe(CN) 6 , and immersed in 2 mM X-Gluc (5-bromo-4-chloro-3-indolyl glucuronide, sigma) and vacuumed for 1 min. After staining at 37° C. in the dark until the color was changed, the plant was incubated in 90% ethanol to remove chlorophyll.
Experimental Results
[0077] The AtAIRP2 Gene Expression after Stress Treatments (Salt, Low-Temperature and Drought)
[0078] The AtAIRP2 gene expressions in various abiotic stresses were analyzed by RT-PCR. After treatments of low-temperature (12 hours and 24 hours), drought (1 hour and 2 hours), salt (1.5 hour and 3 hours) and ABA hormone (1.5 hour and 3 hours) stresses, RNA from each of samples was extracted to analyze the gene expression patterns. As a result, it was determined that the gene expression levels of stress treatments were increased than those of non-stress treatments, thereby the AtAIRP2 gene expression is induced by salt, low-temperature, drought and ABA hormone stresses ( FIG. 1 ). In addition, the AtAIRP2 protein expressions in various abiotic stresses were analyzed by histochemical GUS assay. After treatments of ABA hormone (3 hours) and drought (2 hours) stresses, the degree of the staining was analyzed. As a result, it was determined that the degrees of the staining of stress treatments were increased than those of before the stress treatments ( FIG. 2 ).
Analysis on Enzymatic Activity of the AtAIRP2 Protein
[0079] Maltose-binding protein (MBP) was bound to the AtAIRP2 proteins. Then, the MBP-AtAIRP2 was incubated with UBA1, UBC8, ubiquitin and AtAIRP2 at 30° C. for 1 hour to perform Self-Ubiquitination, and performed by Western blot using MBP- and ubiquitin-specific antibodies to analyze changes in the protein levels. As a result, it was determined that the molecular weight of the AtAIRP2 protein was increased through Western blot using anti-MBP antibody, and the increase was induced due to ubiquitin ( FIG. 3 ). Based on the results, it could be demonstrated that the AtAIRP2 protein possessed ability for enzymatic activity of ligase that binds ubiquitin protein.
Acquisition of the AtAIRP2 Mutants
[0080] As shown in FIG. 4 a , the gene that the T-DNA insertions were mapped to the second exon and the first intron was used in order to prepare the mutants. In order to determine whether to insert and position of T-DNA, genotyping PCR was performed using T-DNA boder primer and primers annealing to sites upstream and downstream of the T-DNA insertion site. As a result, it was determined that T-DNA was inserted in the same direction as that of the gene ( FIG. 4 b ). In addition, in order to determine whether to express mRNA of the full-length AtAIRP2 gene in mutants, the same primers used in genotyping PCR were used. As a result, it was determined that the AtAIRP2 gene was not expressed ( FIG. 4 c ).
Measurement of Sensitivity of Adult Plants to Drought Stress
[0081] In order to measure the tolerance to drought stress in the AtAIRP2 knock-out mutant and the wild type Arabidopsis thaliana , each of the plants was grown for 2 weeks, and subjected to drought stress by withholding water for 13 days, respectively. The plants were then re-watered and monitored the number of the survived plant. As a result, knock-out mutants survived respectively by 25% and 35% whereas the wild types survived by 85%. Therefore, it could be demonstrated that the mutants were less tolerant to drought stress than the wild types ( FIG. 4 d ). In order to measure the tolerance to drought stress in the AtAIRP2-overexpressing transgenic plants, homozygous plants of each of transgenic plants obtained through Basta selection were acquired. The obtained seeds were grown on medium. The protein expressions in transgenic plants of #10 and #19 were verified by Western Blot using anti-GFP ( FIG. 5 a ). In order to compare the tolerance to drought stress on the AtAIRP2-overexpressing transgenic plant and the wild type Arabidopsis thaliana , each of the plants was grown for 2 weeks, and subjected to drought stress by withholding water for 14 days, respectively. The plants were then re-watered and monitored the number of the survived plant. As a result, the AtAIRP2-overexpressing transgenic plant #10 and #19 survived respectively by 87.5% and 84.2% whereas the wild types survived by 10%. Therefore, it could be demonstrated that the transgenic plants were more tolerant to drought stress than the wild types ( FIG. 5 b ).
Comparison of Plant Germination Rate
[0082] As a result of comparison on germination rate in the wild type and the AtAIRP2 knock-out mutant which were grown on medium supplemented with different concentrations (0, 0.1 and 0.5 μM) of ABA hormone for 7 days, it could be understood that the mutant showed the tolerant ( FIG. 6 a ). As a result of comparison on germination rate in the wild type, the AtAIRP2 knock-out mutant and the AtAIRP2-overexpressing transgenic plant which were grown on medium supplemented with different concentrations (0, 0.2 and 0.4 μM) of ABA hormone for 7 days, it could be understood that the germination rates in the AtAIRP2-overexpressing transgenic plants were decreased by ABA hormone and the germination rate in the AtAIRP2 knock-out mutant was increased by ABA hormone ( FIG. 6 b ).
[0083] Those skilled in the art will appreciate that the conceptions and specific embodiments disclosed in the foregoing description may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present disclosure. Those skilled in the art will also appreciate that such equivalent embodiments do not depart from the spirit and scope of the disclosure as set forth in the appended claims. | The present invention relates to a composition for enhancing non-biological stress resistance in plants and a composition for accelerating germination. A nucleotide sequence of the present invention is involved in the resistance against the drying stresses in plants, and a transformed plant in which the nucleotide sequence is overexpressed has prominent resistance against various kinds of non-biological stress, including drought stress. In addition, the nucleotide sequence of the present invention is involved in ABA hormone sensitivity in plants, and germination is greatly improved in a plant in which the nucleotide sequence expression is suppressed. Therefore, the composition of the present invention can be useful as new functional crops regardless of the climate of the cultivation area, or as seeds for long-term storage with an increased storage period. | Condense the core contents of the given document. | [
"BACKGROUND OF THE INVENTION [0001] 1.",
"Field of the Invention [0002] The present invention relates to a gene implicated in abiotic stress tolerance and growth promotion and a method for improving abiotic stress tolerance and promoting growing of transformed plants with the same.",
"[0003] 2.",
"Description of the Related Art [0004] Due to their sessile nature, higher plants are constantly faced with various adverse environmental factors, including drought, high salt, heavy metals, cold, heat shock, and ozone, during their whole life span.",
"These abiotic stresses are a limiting factor for the growth and development of crop plants.",
"Water deficiency causes dramatic reduction of crop production globally, and the decreasing availability of fresh water may pose a future threat to humans and higher plants.",
"Plants have diverse defense strategies to enhance their tolerance to transient and long-term water shortages by triggering signaling network pathways and inducing stress-responsive genes.",
"The cellular and genetic defense mechanisms in response to water stress have been widely documented (Shinozaki and Yamaguchi-Shinozaki, 2007).",
"However, for stress tolerance or sensitivity, our knowledge concerning the biological functions of stress-related genes in higher plants is still rudimentary.",
"Therefore, it is important to study the functions of stress responsive genes to increase the productivity and distribution of crop plants.",
"[0005] Ubiquitin is a protein consisting of 76 amino acids and it has been found in almost all tissues of eukaryotic organisms.",
"Ubiquitin has a characteristic that is covalently bound to various substrate proteins by E1-E2-E3 consecutive actions of ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s) and ubiquitin ligases (E3s).",
"The substrate proteins to be attached with ubiquitin are very diverse, affecting almost all physiological activities.",
"In addition, many studies have been found that the many diseases are associated with these mechanisms.",
"A function of ubiquitin is firstly known to promote degradation of protein by attaching with other proteins.",
"However, other functions of ubiquitin have been recently revealed one after another.",
"[0006] Ubiquitin is attached to substrate by consecutive actions of three types of proteins, i.e., E1, E2 and E3.",
"The glycine residue at the C-terminal domain of ubiquitin binds to NH 3 at R— group of lysine residues on the substrate protein, thereby forming a covalent bond with the substrate.",
"In general, proteins attached with ubiquitin are degraded by proteasome.",
"Polyubiquitin as a chain of several ubiquitin molecules has to be attached to the substrate for degradation by proteasome.",
"Until now, it has been known that proteasome-dependent degradation of the substrate occurs only when polyubiquitin consisting of at least four ubiquitins is attached to the substrate;",
"however, it would be controversial since these results were obtained from in vitro experiments.",
"Polyubiquitination leading to the proteasome-dependent degradation is the linkage form in which the 48 th lysine residue of one ubiquitin is linked to another ubiquitin.",
"[0007] There are 2 types of E1 enzymes in organism.",
"There are various types of E2s.",
"In general, E2s catalyse the transfer of ubiquitin from E1 to E3 or substrate.",
"E3s which are also known as E3 ligases catalyse the final step of the ubiquitination cascade.",
"E3s determine specificity of the substrate to be ubiquitinated.",
"In other words, the substrate being capable of interaction with certain E3s is specifically determined.",
"E3 enzymes may be classified into two major types according to domains.",
"E3 enzymes possess one of two domains: the homologous to the E6-AP carboxyl terminus (HECT) domain and the really interesting new gene (RING) domain.",
"E3 enzymes having RING domain serves to position E2 and substrate in close proximity each other.",
"In other words, where E2 and the substrate bind to E3, distance between ubiquitin of E2 and the substrate is formed to close sufficiently such that ubiquitin of E2 is chemically passed to the substrate.",
"In contrast, E3 enzymes having HECT domain receive ubiquitin from E2, and then transfer it to the substrate.",
"The At5g01520 gene codes for the protein having E3 ubiquitin ligase enzymatic activity.",
"The ubiquitination has been known to serve diverse functions as one of the mechanism that all higher organisms as well as plants have.",
"However, the genes involved in abiotic stresses have been unknown.",
"The present inventors have isolated the At5g01520 genes in which the expression is induced by abiotic stresses and ABA hormone in Arabidopsis thaliana .",
"Then, they have prepared At5g01520s-overexpresors and knock-out mutants and analyzed their physiological phenotypes.",
"[0008] Throughout this application, various publications and patents are referred and citations are provided in parentheses.",
"The disclosures of these publications and patents in their entities are hereby incorporated by references into this application in order to fully describe this invention and the state of the art to which this invention pertains.",
"SUMMARY OF THE INVENTION [0009] The present inventors have made intensive studies to improve a tolerance to abiotic stresses of a plant.",
"As results, they have discovered that a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2 was involved in the above-mentioned characteristic of the plant.",
"In addition, where the gene expression was inhibited, transgenic plants having the improved tolerance to abiotic stresses may be obtained.",
"[0010] Accordingly, it is an object of this invention to provide a composition for improving the tolerance of a plant to an abiotic stress, and a plant cell or a plant exhibiting improved tolerance to an abiotic stress, transformed with the composition.",
"[0011] It is another object of this invention to provide a composition for promoting germination of a plant.",
"[0012] Other objects and advantages of the present invention will become apparent from the following detailed description together with the appended claims and drawings.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIGS. 1 a - d represent results of analyzing the AtAIRP2 gene expression by RT-PCR after treatments of various abiotic stresses and ABA hormone.",
"After treatments of ABA hormone ( FIG. 1 a ), drought stress ( FIG. 1 b ), low-temperature stress ( FIG. 1 c ) and salt stress ( FIG. 1 d ), each RNA was extracted to analyze the gene expression pattern.",
"RD29A was used as a representative control gene in treatments of drought, salt and low-temperature, and RAB18 was used as a representative control gene in treatment of ABA.",
"[0014] FIG. 2 represents results of analyzing the promoter activity of the AtAIRP2 gene by GUS assay.",
"When 100 μM ABA (3 hours) or drought (2 hours) condition was treated, GUS signals were markedly induced.",
"It could be determined that promoter activity of the AtAIRP2 gene was increased.",
"[0015] FIG. 3 represents results of analyzing the enzymatic activity of the AtAIRP2 protein.",
"Maltose-binding protein (MBP) was bound to the AtAIRP2 proteins.",
"Then, MBP-AtAIRP2 was incubated with HIS-UBA1, HIS-UBC8, ubiquitin and AtAIRP2 at 30° C. for 1 hour to perform Self-Ubiquitination, and performed by Western blot using MBP- and ubiquitin-specific antibodies to analyze changes in the protein levels.",
"As a result, it was determined that the molecular weight of the AtAIRP2 protein was increased through Western blot using anti-MBP antibody, and the increase was induced due to ubiquitin.",
"Based on the results, it could be demonstrated that the AtAIRP2 protein possessed ability for enzymatic activity of E3 ubiquitin ligase that binds ubiquitin protein.",
"[0016] FIGS. 4 a - d represent results of measuring the AtAIRP2 gene mutants and their tolerance to drought stress.",
"FIG. 4 a represents the gene map that the T-DNAs were inserted to the exon (AtAIRP2-1) and the intron (AtAIRP2-2) in genomic DNA of the AtAIRP2 gene.",
"FIG. 4 b represents that T-DNA insertions were verified by PCR amplification using the T-DNA border primer and primers annealing to sites upstream and downstream of the T-DNA insertion site with the extracted genomic DNA from the knock-out mutant.",
"FIG. 4 c represents that the expression of the gene was analyzed by RT-PCR with the extracted RNA from the knock-out mutant.",
"Based on the results, it could be demonstrated that the expression of the gene in the AtAIRP2 mutant was inhibited.",
"FIG. 4 d represents images of comparing the tolerance to drought stress in the AtAIRP2 gene mutants and the wild type Arabidopsis thaliana .",
"Each of plants was grown for 2 weeks, and subjected to drought stress by withholding water for 13 days, respectively.",
"The plants were then re-watered and monitored the number of the survived plant.",
"As a result, mutants were less tolerant to drought stress than the wild types ( FIG. 4 d ).",
"[0017] FIGS. 5 a - b represent results of the AtAIRP2-overexpressing transgenic plants.",
"Arabidopsis thaliana was transformed by 355:AtAIRP2-GFP recombinant vector and it was verified whether to overexpress the gene using anti-GFP antibody ( FIG. 5 a ).",
"As a result of Western blot, it could be demonstrated that the AtAIRP2-GFP protein was well-expressed.",
"FIG. 5 b represents images of comparing the tolerance to drought stress in the AtAIRP2-overexpressing transgenic and the wild type Arabidopsis thaliana .",
"Each of plants was grown for 2 weeks, and subjected to drought stress by withholding water for 14 days, respectively.",
"The plants were then re-watered and monitored the number of the survived plant.",
"As a result, the AtAIRP2-overexpressing transgenic plants were more tolerant to drought stress than the wild types.",
"[0018] FIGS. 6 a - b represent results of analyzing germination rates according to ABA hormone in the AtAIRP2 knock-out mutant and the AtAIRP2-overexpressing transgenic plant.",
"FIG. 6 a represents images of the wild type, the AtAIRP2-1 mutant and the AtAIRP2-2 mutant which were grown on medium supplemented with different concentrations (0.1 and 0.5 μM) of ABA hormone for 7 days.",
"It could be understood that the germination rates of mutants which were grown on medium supplemented with ABA hormone were higher than that of the wild types.",
"FIG. 6 b represents images of the wild type, the AtAIRP2-2 mutant and the AtAIRP2-sGFP overexpressing transgenic plant which were grown on medium supplemented with different concentrations (0.2 and 0.4 μM) of ABA hormone for 7 days.",
"It could be understood that the germination rates of the AtAIRP2 overexpressing transgenic plants which were grown on medium supplemented with ABA hormone were significantly inhibited.",
"In addition, it could be demonstrated that the AtAIRP2-2 mutant showed the tolerant under the same condition.",
"Therefore, it could be understood that the germination rates in the AtAIRP2-overexpressing transgenic plants were decreased by ABA hormone and the germination rate in mutant was increased by ABA hormone.",
"DETAILED DESCRIPTION OF THE INVENTION [0019] In one aspect of this invention, there is provided a composition for improving the tolerance of a plant to an abiotic stress, comprising a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2.",
"[0020] The present inventors have made intensive studies to improve a tolerance to abiotic stresses of a plant.",
"As results, they have discovered that a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2 was involved in the above-mentioned characteristic of the plant.",
"In addition, where the gene expression was inhibited, transgenic plants having the improved tolerance to abiotic stresses may be obtained.",
"[0021] According to a preferred embodiment, the present nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2 comprises the nucleotide sequence as set forth in SEQ ID NO:1.",
"According to the present invention, the nucleotide sequence as set forth in SEQ ID NO:1 is the nucleotide sequence of the At5g01520 gene in Arabidopsis thaliana , and the gene is named as the AtAIRP2 ( Arabidopsis thaliana ABA Insensitive Ring Protein 2).",
"The gene encodes RING protein having E3 ubiquitin ligase enzymatic activity.",
"The present inventors have found that expressions of the gene were increased by various abiotic stresses and ABA hormone.",
"[0022] It would be obvious to the skilled artisan that the nucleotide sequences used in this invention are not limited to those listed in the appended Sequence Listings.",
"[0023] For nucleotides, the variations may be purely genetic, i.e., ones that do not result in changes in the protein product.",
"This includes nucleic acids that contain functionally equivalent codons, or codons that encode the same amino acid, such as six codons for arginine or serine, or codons that encode biologically equivalent amino acids.",
"[0024] Considering biologically equivalent variations described hereinabove, the nucleic acid molecule of this invention may encompass sequences having substantial identity to them.",
"Sequences having the substantial identity show at least 80%, more preferably at least 90%, most preferably at least 95% similarity to the nucleic add molecule of this invention, as measured using one of the sequence comparison algorithms.",
"Methods of alignment of sequences for comparison are well-known in the art.",
"Various programs and alignment algorithms are described in: Smith and Waterman, Adv.",
"Appl.",
"Math.",
"2:482(1981);",
"Needleman and Wunsch, J. Mol.",
"Bio.",
"48:443(1970);",
"Pearson and Lipman, Methods in Mol.",
"Biol.",
"24: 307-31(1988);",
"Higgins and Sharp, Gene 73:237-44(1988);",
"Higgins and Sharp, CABIOS 5:151-3(1989) Corpet et al.",
", Nuc.",
"Acids Res.",
"16:10881-90(1988) Huang et al.",
", Comp.",
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"8:155-65(1992) and Pearson et al.",
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"The NCBI Basic Local Alignment Search Tool (BLAST) [Altschul et al.",
", J. Mol.",
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"215:403-10(1990)] is available from several sources, including the National Center for Biological Information (NBCI, Bethesda, Md.) and on the Internet, for use in connection with the sequence analysis programs blastp, blasm, blastx, tblastn and tblastx.",
"It can be accessed at http://www.",
"ncbi.",
"nlm.",
"nih.gov/BLAST/.",
"A description of how to determine sequence identity using this program is available at http://www.",
"ncbi.",
"nlm.",
"nih.gov/BLAST/blast_help.",
"html.",
"[0025] According to a preferred embodiment, the present abiotic stress is selected from the group consisting of a drought stress, a low-temperature stress and a salt stress.",
"[0026] According to the present invention, the present inventors have demonstrated that expressions of the At5g01520 gene were increased when plants were subjected to drought stress, low-temperature stress or salt stress.",
"In addition, they have demonstrated that the tolerances to these stresses were improved when the gene was over-expressed in plants.",
"[0027] More preferably, the present abiotic stress is drought stress.",
"[0028] In another aspect of this invention, there is provided a composition for improving a tolerance of a plant to an abiotic stress, comprising a recombinant plant expression vector which comprises: (a) the nucleotide sequence as disclosed in the present invention;",
"(b) a promoter which is operatively linked to the nucleotide sequence of (a) and generates a RNA molecule in plant cells;",
"and (c) a poly A signal sequence inducing polyadenylation at the 3′-end of the RNA molecule.",
"[0029] The term “operatively linked”",
"as used herein refers to functional linkage between a nucleic acid expression control sequence (such as a promoter, signal sequence, or array of transcription factor binding sites) and a second nucleotide sequence, wherein the expression control sequence affects transcription and/or translation of the nucleic acid corresponding to the second sequence.",
"[0030] The vector system of this invention may be constructed in accordance with conventional techniques described in Sambrook et al.",
", Molecular Cloning, A Laboratory Manual , Cold Spring Harbor Laboratory Press (2001), teachings of which are incorporated herein by reference.",
"[0031] The suitable promoter in the present invention includes any one commonly used in the art, for example SP6 promoter, T7 promoter, T3 promoter, PM promoter, maize-ubiquitin promoter, Cauliflower mosaic virus (CaMV)-35S promoter, Nopalin synthase (nos) promoter, Figwort mosaic virus 35S promoter, Sugarcane bacilliform virus promoter, commelina yellow mottle virus promoter, photo-inducible promoter of small subunit of Ribulose-1,5-bis-phosphate carboxylase (ssRUBISCO), cytosolic triosphosphate isomerase (TPI) promoter in rice, adenine phosphoribosyltransferase (APRT) or octopine synthase promoter in Arabidopsis .",
"Preferably, the promoter used in this invention is CaMV 35S.",
"[0032] According to a preferred embodiment, the poly A signal sequence inducing polyadenylation at the 3′-end includes that from the nopaline synthase gene of Agrobacterium tumefaciens (NOS 3′ end) (Bevan et al.",
", Nucleic Acids Research, 11(2):369-385(1983)), that from the octopine synthase gene of Agrobacterium tumefaciens , the 3′-end of the protease inhibitor I or II genes from potato or tomato, the CaMV 35S terminator, and OCS (octopine synthase) terminator.",
"Most preferably, the poly A signal sequence inducing polyadenylation at the 3′-end in this invention is OCS (octopine synthase) terminator.",
"[0033] Optionally, the present vector for plants may further carry a reporter molecule (e.g., genes for luciferase and β-glucuronidase).",
"In addition, the vector may contain antibiotic resistant genes as selective markers (e.g., neomycin phosphotransferase gene (nptII) and hygromycin phosphotransferase gene (hpt)).",
"[0034] According to a preferred embodiment, the plant expression vector of this invention is Agrobacterium binary vectors.",
"[0035] The term “binary vector”",
"as used herein, refers to a cloning vector containing two separate vector systems harboring one plasmid responsible for migration consisting of left border (LB) and right border (RB), and another plasmid for target gene-transferring.",
"Any Agrobacterium suitable for expressing the nucleotide of this invention may be used, and most preferably, the transformation is carried out using Agrobacterium tumefaciens GV3101.",
"[0036] Introduction of the recombinant vector of this invention into Agrobacterium can be carried out by a large number of methods known to one skilled in the art.",
"For example, particle bombardment, electroporation, transfection, lithium acetate method and heat shock method may be used.",
"Preferably, the electroporation is used.",
"[0037] In still another aspect of this invention, there is provided a plant cell exhibiting improved tolerance to an abiotic stress, transformed with the composition of this invention.",
"[0038] In further aspect of this invention, there is provided a plant exhibiting improved tolerance to an abiotic stress, transformed with the composition of this invention.",
"[0039] To introduce a foreign nucleotide sequence into plant cells or plants may be performed by the methods ( Methods of Enzymology , Vol. 153 (1987)) known to those skilled in the art.",
"The plant may be transformed using the foreign nucleotide inserted into a carrier (e.g., vectors such as plasmid or virus) or Agrobacterium tumefaciens as a mediator (Chilton et al.",
", Cell, 11:263:271 (1977)) and by directly inserting the foreign nucleotide into plant cells (Lorz et al.",
", Mol.",
"Genet.",
", 199: 178-182 (1985);",
"the disclosure is herein incorporated by reference).",
"For example, electroporation, microparticle bombardment, polyethylene glycol-mediated uptake may be used in the vector containing no T-DNA region.",
"[0040] Generally, Agrobacterium -mediated transformation is the most preferable (U.S. Pat. Nos. 5,004,863, 5,349,124 and 5,416,011), and the skilled artisan can incubate or culture the transformed cells or seeds to mature plants in appropriate conditions.",
"[0041] The term “plant(s)”",
"as used herein, is understood by a meaning including a plant cell, a plant tissue and a plant seed as well as a mature plant.",
"[0042] The plants applicable of the present invention include, but not limited to, food crops such as rice plant, wheat, barley, corn, bean, potato, Indian bean, oat and Indian millet;",
"vegetable crops such as Arabidopsis sp.",
", Chinese cabbage, radish, red pepper, strawberry, tomato, watermelon, cucumber, cabbage, melon, pumpkin, welsh onion, onion and carrot;",
"crops for special use such as ginseng , tobacco plant, cotton plant, sesame, sugar cane, sugar beet, Perilla sp.",
", peanut and rape;",
"fruit trees such as apple tree, pear tree, jujube tree, peach tree, kiwi fruit tree, grape tree, citrus fruit tree, persimmon tree, plum tree, apricot tree and banana tree;",
"flowering crops such as rose, gladiolus, gerbera , carnation, chrysanthemum , lily and tulip;",
"and fodder crops such as ryegrass, red clover, orchardgrass, alfalfa, tallfescue and perennial ryograss.",
"[0043] In still further aspect of this invention, there is provided a composition for promoting germination of a plant comprising a nucleic acid molecule, wherein nucleic acid molecule inhibits an expression of a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2.",
"[0044] According to a preferred embodiment, the present nucleotide sequence comprises the nucleotide sequence as set forth in SEQ ID NO:1.",
"[0045] According to the present invention, the nucleotide sequence as set forth in SEQ ID NO:1 is the nucleotide sequence of the At5g01520 gene.",
"According to the present invention, it was determined that Where expressions of the present nucleotide sequence were inhibited, the sensitivity to ABA hormone suppressing immature-germination was decreased such that the germination rates were increased.",
"Therefore, the present nucleic acid molecule enables to store seeds for a long time with excellent germination rates.",
"[0046] According to a preferred embodiment, the nucleic acid molecule is T-DNA, siRNA, shRNA, miRNA, ribozyme, PNA (peptide nucleic acids) or antisense oligonucleotide.",
"More preferably, the present nucleic acid molecule is T-DNA.",
"[0047] The term “siRNA”",
"used herein refers to a short double strand RNA that enables to mediate RNA interference via cleavage of mRNA.",
"The siRNA of the present invention may consist of a sense RNA strand having a sequence corresponding to a target gene and an antisense RNA strand having a sequence complementary to the target gene.",
"The siRNA to inhibit expression of a target gene provides effective gene knock-down method or gene therapy method.",
"[0048] The siRNA of this invention is not restricted to a RNA duplex of which two strands are completely paired and may comprise non-paired portion such as mismatched portion with non-complementary bases and bulge with no opposite bases.",
"The overall length of the siRNA is 10-100 nucleotides, preferably 15-80 nucleotides, and more preferably, 20-70 nucleotides.",
"The siRNA may comprise either blunt or cohesive end so long as it enables to inhibit the target gene expression via RNAi effect.",
"The cohesive end may be prepared in 3′-end overhanging structure or 5′-end overhanging structure.",
"The base number protruded is not particularly limited, for example 1-8 bases, preferably 2-6 bases.",
"In addition, siRNA may comprise low molecular weight RNA (for example, tRNA, rRNA, natural RNA molecule such as viral RNA or artificial RNA molecule) in the protruded portion of one end to the extent that it enables to maintain an effect on the inhibition of target gene expression.",
"The terminal structure of siRNA is not demanded as cut structure at both ends, and one end portion of double strand RNA may be stem-and-loop structure linked by a linker RNA.",
"The length of linker is not restricted where it has no influence on the pair formation of the stem portion.",
"[0049] The term “shRNA”",
"used herein refers to a single strand nucleotide consisting of 50-70 bases, and forms stem-loop structure in vivo.",
"Long RNA of 19-29 nucleotides is complementarily base-paired at both directions of loop consisting of 5-10 nucleotides, forming a double-stranded stem.",
"[0050] The term “miRNA (microRNA)”",
"functions to regulate gene expression and means a single strand RNA molecule composed of 20-50 nucleotides in full-length, preferably 20-45 nucleotides, more preferably 20-40 nucleotides, much more preferably 20-30 nucleotides and most preferably, 21-23 nucleotides.",
"The miRNA is an oligonucleotide which is not expressed intracellularly, and forms a short stem-loop structure.",
"The miRNA has a whole or partial complementarity to one or two or more mRNAs (messenger RNAs), and the target gene expression is suppressed by the complementary binding of miRNA to the mRNA thereof.",
"[0051] The term used herein “ribozyme”",
"refers to a RNA molecule having an activity of an enzyme in itself which recognizes and restricts a base sequence of a specific RNA.",
"The ribozyme consists of a binding portion capable of specifically binding a base sequence complementary to a transfer RNA strand and an enzymatic portion to cut target RNA.",
"[0052] The term “PNA (peptide nucleic acid)”",
"used herein refers to a molecule having the characteristics of both nucleic acid and protein, which is capable of complementarily binding to DNA or RNA.",
"PNA was first reported in 1999 as similar DNA in which nucleobases are linked via a peptide bond (Nielsen P E, Egholm M, Berg R H, Buchardt O, “Sequence-selective recognition of DNA by strand displacement with a thymine-substituted polyamide”, Science 1991, Vol. 254: pp 1497-1500).",
"PNA is absent in the natural world and artificially synthesized through a chemical method.",
"PNA is reacted with a natural nucleic acid having a complementary base sequence through hybridization response, forming double strand.",
"In the double strand with the same length, PNA/DNA and PNA/RNA double strand are more stable than DNA/DNA and DNA/RNA double strand, respectively.",
"The form of repeating N-(2-aminoethyl)-glycine units linked by amide bonds is commonly used as a basic peptide backbone.",
"In this context, the backbone of peptide nucleic acid is electrically neutral in comparison to that of natural nucleic acids having negative charge.",
"Four bases of nucleic acid present in PNA are almost the same to those of natural nucleic acid in the respect of spatial size and distance between nucleobases.",
"PNA has not only a chemical stability compared with natural nucleic acid, but also a biological stability due to no degradation by a nuclease or protease.",
"[0053] The term “antisense oligonucleotide”",
"used herein is intended to refer to nucleic acids, preferably, DNA, RNA or its derivatives, that are complementary to the base sequences of a target mRNA, characterized in that they bind to the target mRNA and interfere its translation to protein.",
"The antisense oligonucleotide of the present invention refers to DNA or RNA sequences which are complementary to a target mRNA, characterized in that they bind to the target mRNA and interfere its translation to protein, translocation into cytoplasm, maturation or essential activities to other biological functions.",
"The length of antisense nucleic acids is in a range of 6-100 nucleotides and preferably 10-40 nucleotides.",
"[0054] The antisense oligonucleotides may be modified at above one or more positions of base, sugar or backbone to enhance their functions [De Mesmaeker, et al.",
", Curr Opin Struct Biol.",
", 5(3): 343-55 (1995)].",
"The oligonucleotide backbone may be modified with phosphothioate, phosphotriester, methyl phosphonate, single chain alkyl, cycloalkyl, single chain heteroatomic, heterocyclic bond between sugars, and so on.",
"In addition, the antisense nucleic acids may include one or more substituted sugar moieties.",
"The antisense oligonucleotides may include a modified base.",
"The modified base includes hypoxanthine, 6-methyladenine, 5-me pyrimidine (particularly, 5-methylcytosine), 5-hydroxymethylcytosine (HMC), glycosyl HMC, gentobiosyl HMC, 2-aminoadenine, 2-thiouracil, 2-thiothymine, 5-bromouracil, 5-hydroxymethyluracil, 8-azaguanine, 7-deazaguanine, N6(6-aminohexyl)adenine, 2,6-diaminopurine, and so forth.",
"[0055] The term “T-DNA”",
"used herein refers to a DNA fragment as a transfer DNA in Ti (tumor-inducing) plasmid of Agrobacterium sp.",
", which is transferred into a nucleus of a host plant cell.",
"A 25 bp repeat sequence is present in both termini of T-DNA, and DNA transfer proceeds at the direction from a left border to a right border.",
"A bacterial T-DNA with about 20,000 in length destroys a target gene by insertion, resulting in insertional muatagenesis.",
"In addition to mutation, inserted T-DNA sequence may label a target gene.",
"According to the present invention, the present inventors have used seeds of Arabidopsis thaliana for suppressing the expression of the At5g01520 gene by means of Ti-plasmid transformation.",
"[0056] In still further aspect of this invention, there is provided a composition for promoting germination of a plant, comprising a recombinant plant expression vector which comprises: (a) the nucleotide sequence as disclosed in the present invention;",
"(b) a promoter which is operatively linked to the nucleotide sequence of (a) and generates a RNA molecule in plant cells;",
"and (c) a poly A signal sequence inducing polyadenylation at the 3′-end of the RNA molecule.",
"[0057] Since the nucleic acid molecule, the plant expression recombinant vector and the introduction method thereof are mentioned above, they are omitted herein to avoid excessive overlaps.",
"[0058] The features and advantages of the present invention will be summarized as follows: [0059] (a) The present invention provides a composition for improving the tolerance of a plant to an abiotic stress and a composition for promoting germinating of a plant.",
"[0060] (b) The present nucleotide sequence is involved in tolerance to drought stress of plants.",
"Therefore, the overexpressing transgenic plants have excellent tolerances to various abiotic stresses including drought stress, whereby they may be useful as novel functional crops which are affected by climates and environments of the cultivated areas.",
"[0061] (c) In addition, the present nucleotide sequence is involved in sensitivity to ABA hormone of plants.",
"Therefore, germination abilities of the knock-out mutant plants in which the expression is inhibited are remarkably enhanced, whereby they may effectively used for cultivating the plants with novel function of storage period increasing, and biomass.",
"[0062] The present invention will now be described in further detail by examples.",
"It would be obvious to those skilled in the art that these examples are intended to be more concretely illustrative and the scope of the present invention as set forth in the appended claims is not limited to or by the examples.",
"EXAMPLES Experimental Methods Isolation of the Genes [0063] The present inventors have isolated the AtAIRP2 genes inducible by ABA hormone and abiotic stresses from cDNAs of Arabidopsis thaliana.",
"10-day-old Arabidopsis thaliana seedlings were grinded with liquid nitrogen in mortar.",
"The powders were added with 2 ml of an extraction buffer (4 M guanidine-HCl 20 mM, 10 mM EDTA, 10 mM EGTA (USB), 0.5% Sarkosyl (SIGMA), pH 9) and β-mercaptoethanol (SIGMA-ALDRICH) per 1 g of the powder for extraction.",
"The extraction resultant was transferred to new conical tube, suspended with an equal volume of PCI (phenol:chloroform:isoamyl alcohol=25:24:1), vortexed for 5 min and centrifuged at 3,500 rpm for 25 min (Hanil centrifuge, HA-1000-3).",
"After centrifugation, the upper organic solvent phase was removed.",
"The extract was resuspended with an equal volume of PCI, vortexed and centrifuged twice.",
"Then, the lower aqueous phase was undergone twice ethanol precipitation and once LiCl precipitation to isolate RNA.",
"RNA was quantified.",
"Single-strand cDNA was synthesized by using 2 μg of RNA with oligo dT primer and MMLV reverse transcriptase (Fermentas).",
"PCR was conducted in the final volume of 50 μL containing 20 ng of cDNA as a template, 10 pmole of each of two types of primers, 5 μL of 10× Taq polymerase buffer (Takara), 8 μL of dNTPs (each of 1.25 mM) and 1 unit of Taq DNA polymerase (Takara).",
"The tube containing the reaction mixture was placed in Perkin Elmer DNA thermal cycler.",
"The sequences of primers used in this Example are as follows: 5′-ATGCGAAAATCGTTCAAGGA-3′ (AtAIRP2 ORF FW: SEQ ID NO: 3) and 5′-TCACCGAGGAAGAGGAGCATAA-3′ (AtAIRP2 ORF RV: SEQ ID NO: 41).",
"The reaction mixture was denatured for 2 min at 94° C. and subjected to 30 cycles of 30 sec at 94° C., 30 sec at 52° C. and 1 min at 72° C. After 30 cycles, polymerization was further performed at 72° C. for 5 min.",
"Then, the AtAIRP2 gene amplification was verified by using electrophoresis method.",
"In addition, the DNA was confirmed by sequencing.",
"Plant Growth Conditions and Sampling [0064] In order to prepare the AtAIRP2-overexpressing transgenic plants, Invitrogen gateway system was used to construct.",
"First, AtAIRP1-sGFP was introduced into pENTR SD Topo vector (Invitrogen, USA) and subsequently integrated into pEarlygate 100 vector ( Arabidopsis research center, USA) of plants using LR clonase enzyme (Invitrogen).",
"[0065] Seeds of the AtAIRP2 knock-out mutants (seed number: SAIL_686_G08 (AtAIRP2-1), Salk_005082 (AtAIRP2-2)) which are T-DNA insertion lines were purchased from SIGNAL Salk Institute Genomic Analysis Laboratory (http://signal.",
"salk.edu/).",
"[0066] The seeds of the AtAIRP2-overexpressing transgenic plants, knock-out mutants and the wild type Arabidopsis thaliana were soaked in 30% bleach solution (Yuhanclorox) and 0.025% Triton X-100 for 10 min, and washed 10 times with sterilized water.",
"The treated seeds were grown on MS (Murashige and Skoog) medium (Duchefa Biochemie) that contained 3% sucrose, B5 vitamin (12 mg/L) and 0.8% agar (pH 5.7) in a growth chamber for 2 weeks (under a condition of 16 hrs-light/8 hrs-dark cycle).",
"Where green whole plants of light condition were used as materials, seeds were grown on soil of Sunshine MIX #5 (Sun GroHorticulture) in a growth chamber for 3 weeks (under a condition of 16 hrs-light/8 hrs-dark cycle).",
"Treatments of Stresses (Salt, Low-Temperature, Drought and ABA Hormone) [0067] In order to determine expressions of the AtAIRP2 gene to drought stress, the wild type Arabidopsis thaliana seedlings which were grown on medium for 2 weeks were exposed in the air, and sampled after 1 hour and 2 hours.",
"In order to determine expressions of the AtAIRP2 gene to salt stress, the wild type Arabidopsis thaliana seedlings which were grown on medium for 2 weeks were treated with 300 mM sodium chloride, and sampled after 1.5 hour and 3 hours.",
"In order to determine expressions of the AtAIRP2 gene to low-temperature stress, the wild type Arabidopsis thaliana seedlings which were grown on medium for 2 weeks were incubated at 4° C. for 12 hours and 24 hours, and sampled.",
"In order to determine expressions of the AtAIRP2 gene to ABA hormone stress, the wild type Arabidopsis thaliana seedlings which were grown on medium for 2 weeks were treated with 100 μM of ABA (SIGMA), and sampled after 1.5 hour and 3 hours.",
"The sampled tissues were grinded with liquid nitrogen in mortar.",
"The powders were added with β-mercaptoethanol (SIGMA-ALDRICH) and 2 ml of an extraction buffer (4 M guanidine-HCl 20 mM, 10 mM EDTA, 10 mM EGTA (USB), 0.5% Sarkosyl (SIGMA), pH 9) per 1 g of the powder to extract.",
"The extract was transferred to new conical tube, suspended with an equal volume of PCI (phenol:chloroform:isoamyl alcohol=25:24:1), vortexed for 5 min and centrifuged at 3,500 rpm for 25 min (Hanil centrifuge, HA-1000-3).",
"After centrifugation, the supernatant which is upper organic solvent phase was removed.",
"The extract was resuspended with an equal volume of PCI, vortexed and centrifuged.",
"The extract was performed twice with the process described above.",
"Then, the lower aqueous phase was performed twice with ethanol precipitation and once with LiCl precipitation to isolate RNA.",
"Quantitative Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) [0068] Total RNA was isolated from leaves of the AtAIRP2-overexpressing transgenic plants, knock-out mutants and the wild type Arabidopsis thaliana .",
"Single-strand cDNA was synthesized by using 2 μg of RNA with oligo dT primer and MMLV reverse transcriptase (Fermentas).",
"PCR was conducted in the final volume of 50 μL containing 20 ng of cDNA as a template, 10 pmole of each of two types of primers, 5 μL of 10× Taq polymerase buffer (Intron), 8 μL of dNTPs (each of 1.25 mM) and 1 unit of Taq DNA polymerase (Intron).",
"The tube containing the reaction mixture was placed in Perkin Elmer DNA thermal cycler.",
"The reaction mixture was denatured for 2 min at 94° C. and subjected to 25 cycles of 30 sec at 94° C., 30 sec at 52° C. and 1 min at 72° C. After 25 cycles, polymerization was further performed at 72° C. for 5 min.",
"Then, the PCR products were stored at −20° C. in a freezer.",
"The sequences of primers used in this Example are shown in Table 1.",
"[0000] TABLE 1 Primers used in RT-PCR Primer sequence AtAIRP2 RT FW 5′-GATGGTGGCTACGTTCAGA-3′ (SEQ ID: 5) AtAIRP2 RT RV 5′-AAATGTCAATAACCAATGGTTG-3′ (SEQ ID: 6) Rab18 FW 5′-GCGTCTTACCAGAACCGTCC-3′ (SEQ ID: 7) Rab18 RV 5′-CCCTTCTTCTCGTGGTGC-3′ (SEQ ID: 8) RD29a FW 5′-CAGGTGAATCAGGAGTTGTT-3′ (SEQ ID: 9) RD29a RV 5′-CCGGAAATTTATCCTCTTCT-3′ (SEQ ID: 10) UBC10 FW 5′-TGGATATGGCGTCGAAGC-3′ (SEQ ID: 11) UBC10 RV 5′-GTGGGATTTTCCATTTAGCC-3′ (SEQ ID: 12) Extraction of Genomic DNA of Mutants Inserted with T-DNA and Acquisition of Homozygous Mutant [0069] The seeds of the wild type Arabidopsis thaliana and knock-out mutants were grown on soil for 2 weeks and their leave were sampled.",
"The leaves were grinded with liquid nitrogen in mortar.",
"The powders were added with 700 mL of CTAB buffer (2% CTAB, 100 mM Tris pH 8, 20 mM EDTA, 1.4 M NaCl, 2% PVP), mixed and heated at 65° C. for 10 min.",
"The resultants were added to 200 mL of chloroform, mixed and centrifuged.",
"After centrifugation, the supernatant was removed.",
"The resultant was mixed with isopropanol to precipitate DNA.",
"The precipitate was washed with 70% ethanol, dried.",
"The obtained genomic DNA was dissolved in water to use.",
"Genotyping PCR was performed using T-DNA border primer (LB_6313R) and primers annealing to sites upstream and downstream of the T-DNA insertion site.",
"[0000] TABLE 2 Primers used in Genotyping PCR and RT-PCR Primer Sequence LB_6313R 5′-GAGCTGCTATACACTGATCTGAG-3′ (SEQ ID: 13) AtAIRP2 FW1 5′-CGTGTGCTCTACGCGAATC-3′ (SEQ ID: 14) AtAIRP2 RV1 5′-CCCTTAATCAGCAAATATGATATCG-3′ (SEQ ID: 15) [0070] It was revealed that the T-DNA insertions were mapped to the second exon and the first intron in the AtAIRP2 gene knock-out mutant, which was verified by PCR amplification using the T-DNA border primer and primers annealing to sites upstream and downstream of the T-DNA insertion site ( FIG. 4 b ).",
"In addition, the suppression of the gene expression was analyzed by RT-PCR using AtAIRP2 FW1 and AtAIRP2 RV1 primers with the extracted RNA from the knock-out mutant ( FIG. 4 c ).",
"Preparation of Vector Construct of the AtAIRP2 Gene [0071] For construction of a recombinant plasmid for expressing the fusion protein between the AtAIRP2 and maltose-binding protein (MBP), PCR was carried out using a primer set designed to contain XbaI and PstI restriction sites linked to 5′-direction and 3′-direction of the coding region of the AtAIRP2 gene, respectively.",
"PCR products and pMAL-X vector (New England Biolabs, Beverly, Mass.) were restricted by XbaI and PstI restriction enzymes and then ligated using T4 DNA ligase (New England Bio Lab).",
"The recombinant MBP-AtAIRP2 was expressed in Escherichia coli strain BL21-CodonPlus (DE3) RIL (Stratagene) and purified using amylose column chromatography.",
"The protein was quantified using BSA as a standard protein.",
"In addition, in the present invention, Invitrogen gateway system was used to construct for preparing transgenic plants.",
"First, AtAIRP2-sGFP was introduced into pENTR SD Topo vector (Invitrogen, USA) and subsequently integrated into pEarlygate 100 vector ( Arabidopsis research center, USA) of plants using LR clonase enzyme (Invitrogen).",
"[0000] AtAIRP2 Transformation with Agrobacterium tumefaciens Strain and Preparation of the AtAIRP2 Transgenic Plants [0072] The prepared constructs were transferred to Agrobacterium tumefaciens strain GV3101 by electroporation.",
"The presence of the gene was confirmed by PCR.",
"An aerial part of approximately 4-week-old Arabidopsis thaliana (columbia [Col-0]) was soaked on MS medium (Duchefa Biochemie) containing 0.05% Silwet for 1.5 min to transform (clough and Bent, 1998, Plant J 16;",
"735-743).",
"The seedlings were grown for 3 weeks in a 23° C.-growth chamber to obtain seeds (T1).",
"The transformed seeds (T1) were selected from medium containing 25 μg/mL of BASTA (Glufosinate ammonium) and 250 μg/mL of carbenicillin.",
"The presence of the transgene was verified by RT-PCR and western blot.",
"Overexpression of the transgene was observed using anti-GFP antibody (clontech).",
"Analysis on Enzymatic Activity of the AtAIRP2 Protein [0073] For the enzymatic activity analysis of the AtAIRP2 protein, the ORF of the AtAIRP2 gene was subcloned into pMAL-X vector in-frame with MBP (maltose-binding protein).",
"40 mM Tris-HCl, pH 7.5, 5 mM MgCl2, 2 mM ATP, 2 mM dithiothreitol (DTT), 300 ng/μL ubiquitin (Sigma), 25 μM MG132 (A.G. Scientific Inc.), 500 ng UBA1 (ABRC, http://www.",
"arabidopsis.org), 500 ng UBC8 (ABRC, http://www.",
"arabidopsis.org) and 500 ng MBP-AtAIRP2 were added to each of tubes and incubated at 30° C. After addition of sample buffer solution, the resultant was heated at 100° C. for 5 min, and performed by Western blot using anti-MBP (New England Bio Labs) and anti-ubiquitin (Santa Cruz) antibodies.",
"Comparison of Plant Growth [0074] For comparing phenotypes to ABA hormone, seeds obtained from the wild type, the AtAIRP2 knock-out mutant and the AtAIRP2-overexpressing transgenic plant were grown on medium supplemented with different concentrations (0, 0.2, 0.4 and 0.5 μM) of ABA hormone for 7 days, and their germination degrees were then measured.",
"In order to compare phenotypes to salt, seeds obtained from the wild type, the AtAIRP2 knock-out mutant and the AtAIRP2-overexpressing transgenic plant were grown on medium supplemented with different concentrations (0, 0.2, 0.4 and 0.5 μM) of sodium chloride for 7 days, and their germination degrees were then measured.",
"Measurement of Sensitivity of Adult Plants to Drought Stress [0075] Seeds obtained from the wild type, the AtAIRP2 knock-out mutant and the AtAIRP2-overexpressing transgenic plant were grown on soil for 2 weeks, and subjected to drought stress by withholding water for 13 or 14 days, respectively.",
"The plants were then re-watered and measured the degrees of the tolerance to drought stress.",
"Histochemical GUS Assay [0076] The wild type Arabidopsis thaliana was grown on medium for 10 days, subjected to 100 mM of ABA hormone and drought stress, and fixed with 90% acetone for 5 min.",
"After removal of the acetone, the plant was washed 3 times with rincing solution containing 50 mM NaPO 4 , 1 mM K 3 Fe(CN) 6 , and 1 mM K 4 Fe(CN) 6 , and immersed in 2 mM X-Gluc (5-bromo-4-chloro-3-indolyl glucuronide, sigma) and vacuumed for 1 min.",
"After staining at 37° C. in the dark until the color was changed, the plant was incubated in 90% ethanol to remove chlorophyll.",
"Experimental Results [0077] The AtAIRP2 Gene Expression after Stress Treatments (Salt, Low-Temperature and Drought) [0078] The AtAIRP2 gene expressions in various abiotic stresses were analyzed by RT-PCR.",
"After treatments of low-temperature (12 hours and 24 hours), drought (1 hour and 2 hours), salt (1.5 hour and 3 hours) and ABA hormone (1.5 hour and 3 hours) stresses, RNA from each of samples was extracted to analyze the gene expression patterns.",
"As a result, it was determined that the gene expression levels of stress treatments were increased than those of non-stress treatments, thereby the AtAIRP2 gene expression is induced by salt, low-temperature, drought and ABA hormone stresses ( FIG. 1 ).",
"In addition, the AtAIRP2 protein expressions in various abiotic stresses were analyzed by histochemical GUS assay.",
"After treatments of ABA hormone (3 hours) and drought (2 hours) stresses, the degree of the staining was analyzed.",
"As a result, it was determined that the degrees of the staining of stress treatments were increased than those of before the stress treatments ( FIG. 2 ).",
"Analysis on Enzymatic Activity of the AtAIRP2 Protein [0079] Maltose-binding protein (MBP) was bound to the AtAIRP2 proteins.",
"Then, the MBP-AtAIRP2 was incubated with UBA1, UBC8, ubiquitin and AtAIRP2 at 30° C. for 1 hour to perform Self-Ubiquitination, and performed by Western blot using MBP- and ubiquitin-specific antibodies to analyze changes in the protein levels.",
"As a result, it was determined that the molecular weight of the AtAIRP2 protein was increased through Western blot using anti-MBP antibody, and the increase was induced due to ubiquitin ( FIG. 3 ).",
"Based on the results, it could be demonstrated that the AtAIRP2 protein possessed ability for enzymatic activity of ligase that binds ubiquitin protein.",
"Acquisition of the AtAIRP2 Mutants [0080] As shown in FIG. 4 a , the gene that the T-DNA insertions were mapped to the second exon and the first intron was used in order to prepare the mutants.",
"In order to determine whether to insert and position of T-DNA, genotyping PCR was performed using T-DNA boder primer and primers annealing to sites upstream and downstream of the T-DNA insertion site.",
"As a result, it was determined that T-DNA was inserted in the same direction as that of the gene ( FIG. 4 b ).",
"In addition, in order to determine whether to express mRNA of the full-length AtAIRP2 gene in mutants, the same primers used in genotyping PCR were used.",
"As a result, it was determined that the AtAIRP2 gene was not expressed ( FIG. 4 c ).",
"Measurement of Sensitivity of Adult Plants to Drought Stress [0081] In order to measure the tolerance to drought stress in the AtAIRP2 knock-out mutant and the wild type Arabidopsis thaliana , each of the plants was grown for 2 weeks, and subjected to drought stress by withholding water for 13 days, respectively.",
"The plants were then re-watered and monitored the number of the survived plant.",
"As a result, knock-out mutants survived respectively by 25% and 35% whereas the wild types survived by 85%.",
"Therefore, it could be demonstrated that the mutants were less tolerant to drought stress than the wild types ( FIG. 4 d ).",
"In order to measure the tolerance to drought stress in the AtAIRP2-overexpressing transgenic plants, homozygous plants of each of transgenic plants obtained through Basta selection were acquired.",
"The obtained seeds were grown on medium.",
"The protein expressions in transgenic plants of #10 and #19 were verified by Western Blot using anti-GFP ( FIG. 5 a ).",
"In order to compare the tolerance to drought stress on the AtAIRP2-overexpressing transgenic plant and the wild type Arabidopsis thaliana , each of the plants was grown for 2 weeks, and subjected to drought stress by withholding water for 14 days, respectively.",
"The plants were then re-watered and monitored the number of the survived plant.",
"As a result, the AtAIRP2-overexpressing transgenic plant #10 and #19 survived respectively by 87.5% and 84.2% whereas the wild types survived by 10%.",
"Therefore, it could be demonstrated that the transgenic plants were more tolerant to drought stress than the wild types ( FIG. 5 b ).",
"Comparison of Plant Germination Rate [0082] As a result of comparison on germination rate in the wild type and the AtAIRP2 knock-out mutant which were grown on medium supplemented with different concentrations (0, 0.1 and 0.5 μM) of ABA hormone for 7 days, it could be understood that the mutant showed the tolerant ( FIG. 6 a ).",
"As a result of comparison on germination rate in the wild type, the AtAIRP2 knock-out mutant and the AtAIRP2-overexpressing transgenic plant which were grown on medium supplemented with different concentrations (0, 0.2 and 0.4 μM) of ABA hormone for 7 days, it could be understood that the germination rates in the AtAIRP2-overexpressing transgenic plants were decreased by ABA hormone and the germination rate in the AtAIRP2 knock-out mutant was increased by ABA hormone ( FIG. 6 b ).",
"[0083] Those skilled in the art will appreciate that the conceptions and specific embodiments disclosed in the foregoing description may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present disclosure.",
"Those skilled in the art will also appreciate that such equivalent embodiments do not depart from the spirit and scope of the disclosure as set forth in the appended claims."
] |
BACKGROUND OF THE INVENTION
The invention concerns a method for the measurement of off-center rotating components of a measured object, whereby the measured object is supported in a rotatable fashion and rotates about a rotational axis and a measurement plane is defined perpendicular to the rotational axis within which the part of the measured object to be measured is irradiated with a parallel beam emanating from a radiative source, and having a detecting means for recording the silhouette of a cross section through the measured object in the measurement plane produced by the radiative source and the measured object, as well as an apparatus for carrying out the method.
An apparatus and a method of this kind have become known in the art by means of the international publication WO86/07442.
The method and apparatus which are known in the art are suitable for determining the dimensions of an elongated measured object. An optical electronic measuring station is proposed for the automatic dimensional control of outer rotating components by means of which the object to be measured is illuminated from below by an linear radiative source in order to produce an image of two diametrically opposed contour points on two linear photodiode arrays. The resulting intensity discontinuities give the two contour points and the shaft diameter can be determined by the electronically recorded separation between the two diode cells.
FIG. 1 shows the fundamental principle of the measurement in accordance with prior art. A radiative source 1 produces a beam 22 comprising parallel rays which illuminates an object to be measured 2 along an optical axis 8. The elongated measured object 2 rotates about a rotational axis which runs through the center 7 perpendicular to the plane of the drawing. A detecting means 3 comprises two separated detector elements 5, 5' whose separation with respect to each other is movable by means of a positioning means 4. Since the beam 22 comprises parallel rays, the position of the beam on the detector 5 produces a silhouette having an intensity profile. The sampled change in the intensity in the vicinity of the edge of the measured object allows, in concert with the electronically determined separation between the two detector linear photocell arrays 5, 5', for a precise dimensional measurement of the measured object. A repeated measurement of the diameter during the rotation facilitates a determination of the roundness of the measured object. With an apparatus in accordance with prior art the resolution for the diameter measurement assumes a value of one micron and the longitudinal precision assumes a value of 0.002 mm. With this apparatus it is possible to measure shafts in the diameter range from 7 to 100 mm having a length from 200 to 700 mm.
Although the measured diameters and roundnesses can be determined quite precisely, the apparatus and the method in accordance with prior art have the disadvantage that asymmetric measured components can not be measured to the required precision, since the rotation of such a component leads to errors in the measurement.
It is therefore the purpose of the present invention to improve an apparatus and a method of the above mentioned kind in such a fashion that rotating components having an asymmetric stroke support position can be measured sufficiently accurately.
SUMMARY OF THE INVENTION
This purpose is achieved in accordance with the method of the invention in that the rotational axis position is adjusted between the detecting means and the beam in such a fashion that the off-center rotating component which is to be measured is illuminated and initially, with a stationary detecting means, the maximum excursion of a diameter of the off-center rotating component is determined by means of a silhouette projection onto the detecting means, an angle of rotation of the off-center rotating component is determined, and the detecting means is synchronized with the position of the angle of rotation and moved parallel to the beam in such a fashion that the separation, parallel to the beam, between the detecting means and the rotating off-center component is kept constant.
The purpose of the invention is likewise realized by means of an apparatus for carrying out the method which exhibits: means for positioning the measurement plane so that it intersects the off-center rotating component to be measured, an angle measuring device to determine an angle of rotation of the off-center rotating component, a stroke means, which is configured in such a fashion that it can move the detecting means parallel to the beam, a synchronizer which synchronizes the stroke motion of the detecting means with the angular position of the off-center component and a computer to store, control and evaluate, whereby the detecting means are moved in such a fashion that the separation parallel to the beam, between the detecting means and the rotating off-center component is kept constant.
In this fashion the purpose of the invention is achieved. By means of a determination of the angular position of the rotating off-center component and by means of a synchronization of this angular position with a position of the detecting means movable parallel to the beam direction, the above mentioned measurement errors due to the changeable positions within the measuring optics can be avoided. During the rotation, an arbitrary point on the off-center rotating component to be measured exhibiting a given constant separation from the rotational axis describes a sinus-shaped motion relative to the optical axis while rotating in a circle about an off-center rotational axis. By means of a corresponding sinus-shaped motion of the detecting means relative to the rotational component, it is possible to maintain its separation, parallel to the beam, from the off-center rotational axis. By means of the measurement of the off-center rotating component at various angular positions during the rotation, it is possible for differing silhouette projections to be recorded, whereby the roundness of the off-center rotating component can also be determined.
It is particularly advantageous when the method is utilized to measure crank shafts. Such an application has the advantage that precision measurements of crank shafts can also be carried out automatically without mechanical contact.
It is also advantageous when the method is carried out to measure crank shafts having a plurality of off-center rotating components with a plurality of angles of rotation relative to each other. A utilization of the measurement procedure for the measurement of crank shafts of this kind has the advantage that even crank shafts having a complicated composition of off-center rotating components and exhibiting various angular positions with respect to each other can be measured automatically and without mechanical contact.
A particularly advantageous embodiment of the apparatus for carrying out the method utilizes two linear photodiode arrays to measure the off-center rotating component. This embodiment has the advantage that the advanced technology of CCD-cameras and laser scanners can be taken advantage of, whereby a plurality of individual measurements per rotation can be carried out.
In a variation of this embodiment, the apparatus exhibits a positioning means in order to adjust the separation between the two linear photodiode arrays. This variation has the advantage that even off-center rotating components with very differing diameters can be measured through the utilization of two adjustable linear photodiode arrays.
An advantageous embodiment of the apparatus for carrying out the method exhibits a positioning device in order to position the detectors transverse to the beam. This embodiment has the advantage that differing edges of the rotating off-center component can be detected at differing angles of rotation during the rotation so that the roundness of the off-center rotating component can also be determined.
Further advantages can be derived from the description and the accompanying drawings. The various features which are to be described can be utilized in other embodiments either individually or in arbitrary combination.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows a brief description of the measurement principle in accordance with prior art;
FIG. 2a shows a cross section in a plane perpendicular to rotational axis of an off-center rotating component to be measured;
FIG. 2b shows a side view of the rotating component to be measured of FIG. 2a with accompanying rotation and detection components;
FIG. 3a shows a side view in the measurement plane where the off-center component to be measured lies on the optical axis at maximum separation from the radiative source;
FIG. 3b shows a representation of the measurement configuration for the case where the off-center component to be measured assumes an angle of 90° relative of that of FIG. 3a during rotation;
FIG. 3c corresponds to the configuration of FIGS. 3a and 3b but for the case where the off-center rotating component to be measured is on the optical axis and as close as possible to the source;
FIG. 4 shows a schematic representation of the connections between control components and the synchronized components in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 describes the fundamental principle of the measurement in accordance with prior art. A radiative source 1 produces a largely parallel beam 22 which irradiates an object 2 to be measured in such a fashion that a silhouette is created on a detecting means 3 equipped with a detector 5, 5'. The vertical position of the detector 5, 5' as well as the separation between possible detector portions 5, 5' is adjusted by means of a transverse positioning means 4.
The roundness of the measured object 2 can be determined by a rotation of the measured object 2 about a rotational axis which runs perpendicular to the plane of the drawing through the rotation center 7 together with an analysis of the intensity discontinuities in detector 5, 5'. An optical axis 8 defines the parallel travel direction of the beam through the rotation center 7. A transverse axis 6 cuts the optical axis 8 in a perpendicular direction through the rotation center 7.
Although, due to the parallel optical path of the beam 22, the measured results, for example with regard to the diameter of the measured object 2, are largely insensitive to small displacements in the direction of the optical axis, large displacements of the measured object along the optical axis cause optical distortions which falsify or degrade the measured results. Consequently, when executing a measurement of a measured object having a off-center rotating component, it is initially not possible to carry out a precise measurement of the off-center rotating component without undertaking additional measures.
FIG. 2a shows a cut in the measurement plane corresponding to the plane of the drawing of FIG. 1 of an object to be measured 2 having an off-center rotating component. The off-center rotating component 10 rotates, in this embodiment, about the rotation center 7 on an off-center stroke circle 13. In many cases, for example in the case of a crank shaft, a point 11 on the edge of the off-center rotating component also describes a circular motion about the rotation center 7 during the rotation of the measured object. In this fashion the off-centered rotating component also exhibits its own off-center rotation center 12 which, for its part, describes an off-center stroke circle 13 about the rotation center 7. During the rotation the off-center rotation center 12 exhibits a changing angle a relative to the transverse axis 6 which, for its part, is perpendicular to the optical axis 8.
FIG. 2b shows a side view of the apparatus. The measured object 2 is supported in a rotatable fashion between rotation means 15 in such a manner that a rotation in the rotation direction 16 about the rotational axis 18 is carried out. During the rotation the off-center rotational axis 19 and the off-center component 10 describe a cylindrical motion about the rotational axis 18 so that a cylinder-shaped surface is swept-out during a rotation of the off-center component. An optical housing 9 is arranged in the vicinity of the off-center component 10 in such a fashion that a precise measurement of the diameter or the roundness of the off-center rotating component 10 can be carried out. A rotational axis positioning means 21 adjusts the position of the optical housing 9 along the rotational axis 18. An angle measuring device 14 is arranged in such a fashion that the angular position or the angle of rotation α of the rotating off-center component is recorded in real time. The measuring plane 17, in which the cross sections according to FIGS. 2a, 3a, 3b and 3c lie, is indicated in FIG. 2b.
In the event that a measurement is carried out in the measurement plane 17 the following steps are executed in accordance with FIGS. 3a, 3b, 3c. FIG. 3a shows the contents of the optical housing 9 having a radiative source 1 which produces the parallel beam 22. During the rotation of the measured object, the off-center component 10 describes an off-center stroke circle 13 about the rotation center 7, whereby a separation d, parallel to the optical axis 8, obtains between the off-center rotation center 12 and the detector 5, 5'. The rotating off-center rotation center 12 is, in FIG. 3a, located precisely on the optical axis 8. Via the transverse positioning means 4 the detectors 5, 5' of the detecting means 3 are positioned in such a fashion that the silhouette of the off-center component 10 which is produced by the projection of the beam 22 is recorded with the detectors 5, 5'. The detectors 5, 5' are suitable for detecting the radiation from the radiative source 1 and the intensity profile of the silhouette. The intensity measurements of the detector in the shadow of the off-center component 10 are, with the exception of a possible small background, zero. Outside of the shadow the intensity naturally corresponds to the complete intensity of the source. Consequently, a sharp intensity profile change occurs precisely at that position where the projection of the edge of the measured object onto the detector plane 5, 5' is produced. The separation d is adjusted by means of a stroke means 20 which will be further described below.
During the rotation the position of the off-center component moves, for example, into the position shown in FIG. 3b. In FIG. 3b the rotating off-center component 10 is precisely in the vertical position, e.g. the off-center center 12 lies on the transverse axis 6. If then, via the transverse positioning means 4, the detectors 5, 5' of the detecting means 3 are adjusted in such a fashion that the sharp intensity change of the silhouette can be detected, a silhouette profile corresponding to the diameter of the measured object is imaged on the detector 5, 5'. The angular position a between the off-center center 12 and the transverse axis 6 (see FIG. 2a) then has, in this position, a value α=0 and, consequently, the off-center rotating component 10 has moved in the direction towards the radiative source 1. Stroke means 20 is, however, adjusted accordingly so that the detecting means are displaced towards the radiative source in such a fashion that the separation d is maintained or kept constant. In this manner optical distortions due to a changing separation between the detector and the off-center component to be measured are avoided.
If one continues to rotate further in accordance with FIG. 3c, then the off-center component 10 is located in a position having an angle of rotation α=270°. The stroke means 20 displaces the position of the detecting means 3 towards the source in such a fashion that the separation d between the off-center rotation center 12 and the detector 5 remains constant. In the event that detector configuration 5, 5' is changed via the transverse positioning means 4 in such a fashion that the silhouette of the off-center component can be detected, a measuring result in accordance with FIG. 3c can be utilized, in combination with FIG. 3a and 3b, to record three diameter measurements of the off-center component 10 and to thereby check the roundness or the eccentricity. The transverse positioning means 4 is also suitable for changing the separation between the two detector parts, for example 5, 5', so that objects of most differing diameters can also be measured.
FIG. 4 shows a schematic diagram of the cooperation and control between the differing components of the system. The synchronizer 30 is connected by means of conductor 47 to the rotation means 15 as well as to the angle measuring device 14 via conductor 43. A connection 44 between the synchronizer 30 and the stroke means 20 allows for the stroke means 20 to be adjusted in such a fashion that the separation parallel to the optical axis 8 between the off-center rotating component and the detecting means is kept constant. The position of the angle of rotation is detected by means of the angle measuring device 14. Additional connections 45 and 42 are shown in FIG. 4 between the synchronizer the transverse positioning means 4, and the computer 40, respectively. Connection 45 facilitates a synchronization of the transverse positioning means 4 with the angle measuring device 14 so that a motion perpendicular to the optical axis, e.g. parallel to axis 6, can also be synchronized with the rotation of the off-center rotating component. Synchronization information is stored via conductor 42 and computer 40. Computer 40 stores, controls and evaluates information. The angle of rotation position a is stored via conductor 41 and the intensity profile of the silhouette detected by detector 5, 5' is read out or stored via conductor 46 or 46'. Clearly, additional conventional connections between the computer 40 and the various components of the system in accordance with FIGS. 2 through 3c are possible in order to effect an automatization of the measuring process.
It is possible, with the method and apparatus in accordance with the invention, to monitor diameters and to measure diameters with a precision of approximately 1 micron. Measurements of this type can, for example, be carried out on measured objects having lengths between 0 and 3000 mm and having diameters between 0 and 1000 mm. Measurement of off-center rotating components can be carried out on, for example, crank shafts. The detecting means 5, 5' can have photocells connected to an optical CCD camera or a laser scanner. With a pixel read-out frequency of, for example, 10 MHz, a sample frequency of 5 KHz is to be expected. With a measured object rotational frequency of 1 Hz, 5000 samples per rotation are possible. Stroke throws of the off-center rotating component of, for example, ±200 mm can be measured with this method and with this apparatus. | An apparatus and a method are presented in order to carry out an automatic optical inspection of an off-center rotating component to be measured. Using a measurement procedure which avoids mechanical contact having a source producing parallel rays and a detecting means, the off-center rotating component is rotated about a rotational axis, whereby a motion of the detecting means is synchronized with the rotation and is carried out in such a fashion that the separation, in the direction of an optical axis, between the off-center rotating component and the detecting means remains constant. In this manner optical distortions are avoided which would otherwise occur in the optical measurement procedure. | Summarize the key points of the given document. | [
"BACKGROUND OF THE INVENTION The invention concerns a method for the measurement of off-center rotating components of a measured object, whereby the measured object is supported in a rotatable fashion and rotates about a rotational axis and a measurement plane is defined perpendicular to the rotational axis within which the part of the measured object to be measured is irradiated with a parallel beam emanating from a radiative source, and having a detecting means for recording the silhouette of a cross section through the measured object in the measurement plane produced by the radiative source and the measured object, as well as an apparatus for carrying out the method.",
"An apparatus and a method of this kind have become known in the art by means of the international publication WO86/07442.",
"The method and apparatus which are known in the art are suitable for determining the dimensions of an elongated measured object.",
"An optical electronic measuring station is proposed for the automatic dimensional control of outer rotating components by means of which the object to be measured is illuminated from below by an linear radiative source in order to produce an image of two diametrically opposed contour points on two linear photodiode arrays.",
"The resulting intensity discontinuities give the two contour points and the shaft diameter can be determined by the electronically recorded separation between the two diode cells.",
"FIG. 1 shows the fundamental principle of the measurement in accordance with prior art.",
"A radiative source 1 produces a beam 22 comprising parallel rays which illuminates an object to be measured 2 along an optical axis 8.",
"The elongated measured object 2 rotates about a rotational axis which runs through the center 7 perpendicular to the plane of the drawing.",
"A detecting means 3 comprises two separated detector elements 5, 5'",
"whose separation with respect to each other is movable by means of a positioning means 4.",
"Since the beam 22 comprises parallel rays, the position of the beam on the detector 5 produces a silhouette having an intensity profile.",
"The sampled change in the intensity in the vicinity of the edge of the measured object allows, in concert with the electronically determined separation between the two detector linear photocell arrays 5, 5', for a precise dimensional measurement of the measured object.",
"A repeated measurement of the diameter during the rotation facilitates a determination of the roundness of the measured object.",
"With an apparatus in accordance with prior art the resolution for the diameter measurement assumes a value of one micron and the longitudinal precision assumes a value of 0.002 mm.",
"With this apparatus it is possible to measure shafts in the diameter range from 7 to 100 mm having a length from 200 to 700 mm.",
"Although the measured diameters and roundnesses can be determined quite precisely, the apparatus and the method in accordance with prior art have the disadvantage that asymmetric measured components can not be measured to the required precision, since the rotation of such a component leads to errors in the measurement.",
"It is therefore the purpose of the present invention to improve an apparatus and a method of the above mentioned kind in such a fashion that rotating components having an asymmetric stroke support position can be measured sufficiently accurately.",
"SUMMARY OF THE INVENTION This purpose is achieved in accordance with the method of the invention in that the rotational axis position is adjusted between the detecting means and the beam in such a fashion that the off-center rotating component which is to be measured is illuminated and initially, with a stationary detecting means, the maximum excursion of a diameter of the off-center rotating component is determined by means of a silhouette projection onto the detecting means, an angle of rotation of the off-center rotating component is determined, and the detecting means is synchronized with the position of the angle of rotation and moved parallel to the beam in such a fashion that the separation, parallel to the beam, between the detecting means and the rotating off-center component is kept constant.",
"The purpose of the invention is likewise realized by means of an apparatus for carrying out the method which exhibits: means for positioning the measurement plane so that it intersects the off-center rotating component to be measured, an angle measuring device to determine an angle of rotation of the off-center rotating component, a stroke means, which is configured in such a fashion that it can move the detecting means parallel to the beam, a synchronizer which synchronizes the stroke motion of the detecting means with the angular position of the off-center component and a computer to store, control and evaluate, whereby the detecting means are moved in such a fashion that the separation parallel to the beam, between the detecting means and the rotating off-center component is kept constant.",
"In this fashion the purpose of the invention is achieved.",
"By means of a determination of the angular position of the rotating off-center component and by means of a synchronization of this angular position with a position of the detecting means movable parallel to the beam direction, the above mentioned measurement errors due to the changeable positions within the measuring optics can be avoided.",
"During the rotation, an arbitrary point on the off-center rotating component to be measured exhibiting a given constant separation from the rotational axis describes a sinus-shaped motion relative to the optical axis while rotating in a circle about an off-center rotational axis.",
"By means of a corresponding sinus-shaped motion of the detecting means relative to the rotational component, it is possible to maintain its separation, parallel to the beam, from the off-center rotational axis.",
"By means of the measurement of the off-center rotating component at various angular positions during the rotation, it is possible for differing silhouette projections to be recorded, whereby the roundness of the off-center rotating component can also be determined.",
"It is particularly advantageous when the method is utilized to measure crank shafts.",
"Such an application has the advantage that precision measurements of crank shafts can also be carried out automatically without mechanical contact.",
"It is also advantageous when the method is carried out to measure crank shafts having a plurality of off-center rotating components with a plurality of angles of rotation relative to each other.",
"A utilization of the measurement procedure for the measurement of crank shafts of this kind has the advantage that even crank shafts having a complicated composition of off-center rotating components and exhibiting various angular positions with respect to each other can be measured automatically and without mechanical contact.",
"A particularly advantageous embodiment of the apparatus for carrying out the method utilizes two linear photodiode arrays to measure the off-center rotating component.",
"This embodiment has the advantage that the advanced technology of CCD-cameras and laser scanners can be taken advantage of, whereby a plurality of individual measurements per rotation can be carried out.",
"In a variation of this embodiment, the apparatus exhibits a positioning means in order to adjust the separation between the two linear photodiode arrays.",
"This variation has the advantage that even off-center rotating components with very differing diameters can be measured through the utilization of two adjustable linear photodiode arrays.",
"An advantageous embodiment of the apparatus for carrying out the method exhibits a positioning device in order to position the detectors transverse to the beam.",
"This embodiment has the advantage that differing edges of the rotating off-center component can be detected at differing angles of rotation during the rotation so that the roundness of the off-center rotating component can also be determined.",
"Further advantages can be derived from the description and the accompanying drawings.",
"The various features which are to be described can be utilized in other embodiments either individually or in arbitrary combination.",
"BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows a brief description of the measurement principle in accordance with prior art;",
"FIG. 2a shows a cross section in a plane perpendicular to rotational axis of an off-center rotating component to be measured;",
"FIG. 2b shows a side view of the rotating component to be measured of FIG. 2a with accompanying rotation and detection components;",
"FIG. 3a shows a side view in the measurement plane where the off-center component to be measured lies on the optical axis at maximum separation from the radiative source;",
"FIG. 3b shows a representation of the measurement configuration for the case where the off-center component to be measured assumes an angle of 90° relative of that of FIG. 3a during rotation;",
"FIG. 3c corresponds to the configuration of FIGS. 3a and 3b but for the case where the off-center rotating component to be measured is on the optical axis and as close as possible to the source;",
"FIG. 4 shows a schematic representation of the connections between control components and the synchronized components in accordance with the invention.",
"DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 describes the fundamental principle of the measurement in accordance with prior art.",
"A radiative source 1 produces a largely parallel beam 22 which irradiates an object 2 to be measured in such a fashion that a silhouette is created on a detecting means 3 equipped with a detector 5, 5'.",
"The vertical position of the detector 5, 5'",
"as well as the separation between possible detector portions 5, 5'",
"is adjusted by means of a transverse positioning means 4.",
"The roundness of the measured object 2 can be determined by a rotation of the measured object 2 about a rotational axis which runs perpendicular to the plane of the drawing through the rotation center 7 together with an analysis of the intensity discontinuities in detector 5, 5'.",
"An optical axis 8 defines the parallel travel direction of the beam through the rotation center 7.",
"A transverse axis 6 cuts the optical axis 8 in a perpendicular direction through the rotation center 7.",
"Although, due to the parallel optical path of the beam 22, the measured results, for example with regard to the diameter of the measured object 2, are largely insensitive to small displacements in the direction of the optical axis, large displacements of the measured object along the optical axis cause optical distortions which falsify or degrade the measured results.",
"Consequently, when executing a measurement of a measured object having a off-center rotating component, it is initially not possible to carry out a precise measurement of the off-center rotating component without undertaking additional measures.",
"FIG. 2a shows a cut in the measurement plane corresponding to the plane of the drawing of FIG. 1 of an object to be measured 2 having an off-center rotating component.",
"The off-center rotating component 10 rotates, in this embodiment, about the rotation center 7 on an off-center stroke circle 13.",
"In many cases, for example in the case of a crank shaft, a point 11 on the edge of the off-center rotating component also describes a circular motion about the rotation center 7 during the rotation of the measured object.",
"In this fashion the off-centered rotating component also exhibits its own off-center rotation center 12 which, for its part, describes an off-center stroke circle 13 about the rotation center 7.",
"During the rotation the off-center rotation center 12 exhibits a changing angle a relative to the transverse axis 6 which, for its part, is perpendicular to the optical axis 8.",
"FIG. 2b shows a side view of the apparatus.",
"The measured object 2 is supported in a rotatable fashion between rotation means 15 in such a manner that a rotation in the rotation direction 16 about the rotational axis 18 is carried out.",
"During the rotation the off-center rotational axis 19 and the off-center component 10 describe a cylindrical motion about the rotational axis 18 so that a cylinder-shaped surface is swept-out during a rotation of the off-center component.",
"An optical housing 9 is arranged in the vicinity of the off-center component 10 in such a fashion that a precise measurement of the diameter or the roundness of the off-center rotating component 10 can be carried out.",
"A rotational axis positioning means 21 adjusts the position of the optical housing 9 along the rotational axis 18.",
"An angle measuring device 14 is arranged in such a fashion that the angular position or the angle of rotation α of the rotating off-center component is recorded in real time.",
"The measuring plane 17, in which the cross sections according to FIGS. 2a, 3a, 3b and 3c lie, is indicated in FIG. 2b.",
"In the event that a measurement is carried out in the measurement plane 17 the following steps are executed in accordance with FIGS. 3a, 3b, 3c.",
"FIG. 3a shows the contents of the optical housing 9 having a radiative source 1 which produces the parallel beam 22.",
"During the rotation of the measured object, the off-center component 10 describes an off-center stroke circle 13 about the rotation center 7, whereby a separation d, parallel to the optical axis 8, obtains between the off-center rotation center 12 and the detector 5, 5'.",
"The rotating off-center rotation center 12 is, in FIG. 3a, located precisely on the optical axis 8.",
"Via the transverse positioning means 4 the detectors 5, 5'",
"of the detecting means 3 are positioned in such a fashion that the silhouette of the off-center component 10 which is produced by the projection of the beam 22 is recorded with the detectors 5, 5'.",
"The detectors 5, 5'",
"are suitable for detecting the radiation from the radiative source 1 and the intensity profile of the silhouette.",
"The intensity measurements of the detector in the shadow of the off-center component 10 are, with the exception of a possible small background, zero.",
"Outside of the shadow the intensity naturally corresponds to the complete intensity of the source.",
"Consequently, a sharp intensity profile change occurs precisely at that position where the projection of the edge of the measured object onto the detector plane 5, 5'",
"is produced.",
"The separation d is adjusted by means of a stroke means 20 which will be further described below.",
"During the rotation the position of the off-center component moves, for example, into the position shown in FIG. 3b.",
"In FIG. 3b the rotating off-center component 10 is precisely in the vertical position, e.g. the off-center center 12 lies on the transverse axis 6.",
"If then, via the transverse positioning means 4, the detectors 5, 5'",
"of the detecting means 3 are adjusted in such a fashion that the sharp intensity change of the silhouette can be detected, a silhouette profile corresponding to the diameter of the measured object is imaged on the detector 5, 5'.",
"The angular position a between the off-center center 12 and the transverse axis 6 (see FIG. 2a) then has, in this position, a value α=0 and, consequently, the off-center rotating component 10 has moved in the direction towards the radiative source 1.",
"Stroke means 20 is, however, adjusted accordingly so that the detecting means are displaced towards the radiative source in such a fashion that the separation d is maintained or kept constant.",
"In this manner optical distortions due to a changing separation between the detector and the off-center component to be measured are avoided.",
"If one continues to rotate further in accordance with FIG. 3c, then the off-center component 10 is located in a position having an angle of rotation α=270°.",
"The stroke means 20 displaces the position of the detecting means 3 towards the source in such a fashion that the separation d between the off-center rotation center 12 and the detector 5 remains constant.",
"In the event that detector configuration 5, 5'",
"is changed via the transverse positioning means 4 in such a fashion that the silhouette of the off-center component can be detected, a measuring result in accordance with FIG. 3c can be utilized, in combination with FIG. 3a and 3b, to record three diameter measurements of the off-center component 10 and to thereby check the roundness or the eccentricity.",
"The transverse positioning means 4 is also suitable for changing the separation between the two detector parts, for example 5, 5', so that objects of most differing diameters can also be measured.",
"FIG. 4 shows a schematic diagram of the cooperation and control between the differing components of the system.",
"The synchronizer 30 is connected by means of conductor 47 to the rotation means 15 as well as to the angle measuring device 14 via conductor 43.",
"A connection 44 between the synchronizer 30 and the stroke means 20 allows for the stroke means 20 to be adjusted in such a fashion that the separation parallel to the optical axis 8 between the off-center rotating component and the detecting means is kept constant.",
"The position of the angle of rotation is detected by means of the angle measuring device 14.",
"Additional connections 45 and 42 are shown in FIG. 4 between the synchronizer the transverse positioning means 4, and the computer 40, respectively.",
"Connection 45 facilitates a synchronization of the transverse positioning means 4 with the angle measuring device 14 so that a motion perpendicular to the optical axis, e.g. parallel to axis 6, can also be synchronized with the rotation of the off-center rotating component.",
"Synchronization information is stored via conductor 42 and computer 40.",
"Computer 40 stores, controls and evaluates information.",
"The angle of rotation position a is stored via conductor 41 and the intensity profile of the silhouette detected by detector 5, 5'",
"is read out or stored via conductor 46 or 46'.",
"Clearly, additional conventional connections between the computer 40 and the various components of the system in accordance with FIGS. 2 through 3c are possible in order to effect an automatization of the measuring process.",
"It is possible, with the method and apparatus in accordance with the invention, to monitor diameters and to measure diameters with a precision of approximately 1 micron.",
"Measurements of this type can, for example, be carried out on measured objects having lengths between 0 and 3000 mm and having diameters between 0 and 1000 mm.",
"Measurement of off-center rotating components can be carried out on, for example, crank shafts.",
"The detecting means 5, 5'",
"can have photocells connected to an optical CCD camera or a laser scanner.",
"With a pixel read-out frequency of, for example, 10 MHz, a sample frequency of 5 KHz is to be expected.",
"With a measured object rotational frequency of 1 Hz, 5000 samples per rotation are possible.",
"Stroke throws of the off-center rotating component of, for example, ±200 mm can be measured with this method and with this apparatus."
] |
GOVERNMENT USE
The invention described here may be made, used and licensed by or for the U.S. Government for governmental purposes without paying me royalty.
BACKGROUND AND SUMMARY
One of the pressing problems encountered in modern global peace keeping operations is that mines are encountered in areas travelled by military vehicle having light armor or no armor. The explosive force and shrapnel of the mine detonations penetrate the floors of such vehicle, seriously injuring or killing vehicle occupants. It has been proposed to retrofit such vehicles with mats of cloth-like armor material such as Kevlar™ to reduce damage and injury from shrapnel, which is regarded by some as the more serious problem.
I propose a method to retrofit a vehicle floor panel with a ballistic enhancement mat that not only deters shrapnel but also reinforces the floor panel against the explosive force of a mine blast. My method uses a continuous batt of commercially available batt material. The batt is impregnated by conventional methods with a deformable matrix which is typically made from thermoplastic material. Then the batt is cut into mats shaped in an outline of the vehicle floor panel. Placed on the mat, panel or both is a surface-to-surface bonding agent or attachment mechanism. The mat is laid on the panel and facially conformed to the topography of the panel so that the mat and panel are fixed together all over their interface. The bonding agent or attachment mechanism is such that the topographically conformed mat can later be detached by peeling it from the panel. Once the mat is fixed to the panel, the matrix is hardened by cooling. When the matrix hardens, the mat and floor panel reinforce one another and act as an unitized structural member. If one desires to replace the mat, the mat is resoftened by heating and then peeled from the panel, and thereafter a new mat is installed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a typical vehicle floor panel having superimposed thereon a dashed outline of a fibrous batt unit.
FIG. 2 is section taken from line 2--2 in FIG. 1.
FIG. 3 is a cross section of a vehicle floor panel and adjoining structure, the panel having a mat fit thereon.
FIGS. 4, 5 and 6 are cross sections of a mat on the floor panel.
FIGS. 7 and 8 are detail cross sections of optional structures of the mat.
FIG. 9 shows a process of mat fabrication and installation.
DETAILED DESCRIPTION
In FIG. 1 is a typical metal compartment panel 10 which can be a vehicle floor pan. Panel 10 is welded or otherwise fixed to the body (not shown) or frame member 8 (FIG. 3) or upright panel 6 of a vehicle. Panel 10 can be some other structural panel such as a roof or side wall, or can be an armor panel. Panel 10 is irregular of shape and non-planar in topography, typically having a pan-like recess 12 and a peripheral ridge 14, although panel 10 may have other topographical features such as corrugations, channels or embossed areas. Shown in dashed lines at 16 is the outline of a section of batt 16 from which a liner mat 18 (FIG. 3) is cut for panel 10. Mat 18 is cut so that the mat's peripheral edges will congruently lie along the peripheral edges of panel 10 once mat 18 is fitted thereto. In FIG. 3, for example, mat edges 20 and 22 lie atop corresponding panel edges 24 and 26.
FIG. 4 is a detail view of a partial section of mat 18 and underlying panel 10. In that figure, outer surface layer 28 is an optional flexible protective cover for the mat which keeps dirt, oil or other foreign material from harming interior layers of the mat. Interfaced to layer 28 is flexible armor layer 30 having one or any number of sheets comprised of fibers, strands or braided threads of any suitable fibrous material. Such material includes kevlar™ arimid fiber, polymers such as nylon, metal strands, fiberglass or a combination of these materials. The sheets of armor layer 30 act much the same way as layers of a flack jacket to stop bullets or fragments from entering the compartment of which panel 10 is part. The sheets can have a relatively open weave so as to resemble a mesh, or can have a close weave so as to resemble cloth, or else the sheets can have a knitted structure.
Permeating layer 30 is a thermoplastic matrix material that impregnates the sheets and occupies any interlaminar space between the sheets. Examples of impregnated, layered structure of layer 30 are in the detailed cross section of FIG. 7. The first example comprises fibrous sheets 32 permeated with the thermoplastic material and having substrata 34 between sheets 32. Substrata 34 are comprised of the thermoplastic material, which is integral or continuous with the thermoplastic material permeating sheets 32. The second example (FIG. 7) comprises a series of sheets 32a, 32b, 32c, 32d and 32e that have no interlaminar space therebetween. These latter sheets are also permeated by a thermoplastic material which is continuous with the thermoplastic material of substrata 34.
The thermoplastic material is relatively rigid at ambient temperatures. However, this material typically becomes plastically deformable at temperatures higher than maximum passenger compartment temperatures for a military vehicle. Preferably the material becomes plastic at no lower than 150° F. or therabouts and need not be heated above the boiling point of water to become plastically deformable. Once the thermoplastic material softens at the higher temperatures, the sheets of layer 30 can slide relative to one another and relative to layer 28. It may be desired that, at ambient temperatures, the thermoplastic material is less malleable and more brittle than panel 10. The relatively higher brittleness of the thermoplastic material causes the propagation of cracks in the material as panel 10 bends or bulges due to an explosive impact. This propagation will in some instances absorb enough energy from an explosion to save panel 10, whereby mat 18 functions as sacrificial armor.
In the case of a relatively high brittleness of the thermoplastic material, it is preferred that at one of the sheets is at the laminar boundaries 60 and 62 (FIG. 4) of the matrix material. It is further preferred that at least some of the strands of fibers comprising the sheets of layer 30 be more ductile or malleable than the thermoplastic material. The relatively higher ductility of the fibers will enable them to survive cracking of the thermoplastic material so that the sheets of layer 30 prevent the thermoplastic material from spalling.
As an alternative, the thermoplastic material can be replaced by material sensitive to deformation rate. That is, the material is a strain rate sensitive material whose stress-to-strain ratio increases as speed of deformation increases or attempts to increase. Thus the material will rigidify when subjected to high, sudden impacts from explosions but will deform slowly when subjected lower forces for longer periods. Both the rate sensitive material and the thermoplastic material of the mat matrix may be deemed reversibly or impermanently hardenable. That is, these materials can re-soften after hardening.
Returning to FIG. 4, there is between mat 18 and panel 10 a stratum 36 by which the mat is fastened to panel 10. Stratum 36 can be simply a layer of adhesive completely covering the area between the mat 18 and panel 10. Stratum 36 can be of the same thermoplastic material as that in layer 30 should that material have adhesive qualities. In such a case, the thermoplastic material of stratum 36 would preferably be integrally continuous with the thermoplastic material of layer 30. Alteratively, stratum 36 can be comprised of one of a well known system of hook-and-loop fasteners such as Velcro™ fasteners.
It is contemplated that mat 18 may sometimes be damaged or destroyed by an explosion but panel 10 will survive. Consequently, it may be preferred that stratum 36 allow subsequent removal of mat 18 by applying a relatively light scraping or peeling force, or by the use of solvents. Thereafter a new mat can be installed.
Screws, bolts or like fasteners can also be used to fix mat 18 to panel 10, but doing so requires forming the necessary holes in panel 10 and installation of the mat may become overly time consuming. In addition, the bolts, screws or other fasteners will become concentration points for force when panel 10 is subjected to an explosion. Therefore, to counteract the effect of an explosion, a great number of such fasteners will be needed all over panel 10 to keep mat 18 and panel 10 together.
FIG. 5 shows another structure for mat 18 wherein the outer surface layer 28 and adhesive stratum 36 are unchanged but the mat's middle layers are modified. Adjacent outer layer 28 in FIG. 5 is an impregnated fibrous layer 38 similar in structure to layer 30. Adjacent stratum 36 is another impregnated fibrous layer 40 which is also similar in structure to layer 30. Between layers 38 and 40 is a layer 42 comprising a matrix of earlier described thermoplastic or rate sensitive material in which are inclusions exemplified at 44. As before, the matrix of layer 42 is integrally continuous with the matrix material of layers 38 and 40. Inclusions 44 are a means to reinforce the mat against puncture by relatively small projectiles such as bullets, mine fragments or flying debris. Inclusions 44 are therefore harder than the matrix material is during its more rigid state. Typically inclusions 44 are made of ceramic material or hardened steel and are bonded or adhered to the surrounding matrix of layer 42.
FIG. 6 shows still another structure for mat 18 wherein the outer surface layer 28 and adhesive stratum 36 are unchanged but the mat's middle layer is again modified. In FIG. 6, the middle layer 46 is comprised of a coherent, tomentum-like body of intertangled strands or braided threads. The strands or threads are typically comprised of kevlar™, arimid or like fiber, polymers such as nylon, metal, fiberglass or a mix of these materials. Permeating the tomentum-like body is a matrix of the aforementioned thermoplastic or rate sensitive material having inclusions 44 therein. A layer structured similar to layer 46 may replace either or both of layers 38 and 40 in FIG. 5.
Further potential structures of mat mediate layers and combinations of such layers are shown in FIG. 8. There, layer 48 has a matrix 50 of the thermoplastic or rate sensitive material in which run a set of wire-like elements 52. Transverse to wire-like elements 52 is a second set of wire-like elements 54. Elements 52 and 54 may be resistance heating elements for producing heat within mat 18 or they may simply be heat conduction elements that speed transfer of heat into the mat from an external source.
Another alternative is layer 56, which is similar in structure to layer 46 except that inclusions 44 are absent from layer 56. Layer 58 is similar to layer 46 except that no fibers or strands are in layer 58. Layers 56 or 58 can be used as additional mediate mat layers in the FIG. 5 embodiment; in the alternative, layers 56 or 58 can replace one or more of layers 38, 40 or 42 in FIG. 5.
FIG. 9 illustrates one process by which mats 18 would be fabricated and installed in existing military vehicles. The first step in this process is simply the conventional manufacture of a continuous batt 64. The fibrous material of batt 64 is configured similarly to the fibrous material of layer 30 in FIG. 4. Batt 64 is impregnated with a thermoplastic matrix material so as to have the cross sectional batt structure shown at 66 and similar to layer 30. Batt structure 66 optionally has outer surface layer 28 placed thereon after impregnation of the fibrous material. The continuous batts are then cut into flat rectangular blanks 70 and thereafter trimmed to an outline 72 of the vehicle compartment panel. Next, the trimmed rectangular blanks, which can be regarded now as mats 18, are shipped to world wide locations such as U S Army depots or marshalling yards, designated by reference numeral 68.
After shipping, mats 18 are heated in oven 74 or by other suitable means to soften the thermoplastic matrix material. After being heated, mat 18 is then laid upon panel 10 and conformed to the topography thereof, both the fibrous material and matrix material deforming to match the shape of panel 10. Then mat 18 is allowed to harden and cool. Prior to the laying of mat 18 on panel 10, adhesive can be applied to the panel or the mat, the adhesive bonding the mat to the panel after the mat cools. As noted before, mechanical devices can be used to fix mat 18 to panel 10, these devices including threaded fasteners, clamps or hook-and-loop fasteners. In the case where the mat's matrix material is strain rate sensitive, the heating of mat 18 is omitted.
I wish it to be understood that I do not desire to be limited to the exact details of construction or method shown herein since obvious modifications will occur to those skilled in the relevant arts without departing from the spirit and scope of the following claims. | A method to retrofit a vehicle panel with a ballistic enhancement mat sta by providing a continuous batt of fibrous material. The batt is impregnated with a matrix of material that is, or can be made to be, deformable and then hardened. The batt is cut into mats shaped in an outline of the panel. An individual mat is placed on the panel and conformed to the topography of the panel to create a surface-to-surface interface between the mat and the panel. The mat and panel are fixed together at points all over the interface via an adhesive, a hook-and-loop layer, threaded fasteners or any other suitable mechanical fastening mechanism. The matrix is then hardened, whereby the mat becomes an integral reinforcement mechanism for the panel. The matrix material can be resoftened to facilitate removal of the mat if the mat needs replacement. | Summarize the document in concise, focusing on the main idea's functionality and advantages. | [
"GOVERNMENT USE The invention described here may be made, used and licensed by or for the U.S. Government for governmental purposes without paying me royalty.",
"BACKGROUND AND SUMMARY One of the pressing problems encountered in modern global peace keeping operations is that mines are encountered in areas travelled by military vehicle having light armor or no armor.",
"The explosive force and shrapnel of the mine detonations penetrate the floors of such vehicle, seriously injuring or killing vehicle occupants.",
"It has been proposed to retrofit such vehicles with mats of cloth-like armor material such as Kevlar™ to reduce damage and injury from shrapnel, which is regarded by some as the more serious problem.",
"I propose a method to retrofit a vehicle floor panel with a ballistic enhancement mat that not only deters shrapnel but also reinforces the floor panel against the explosive force of a mine blast.",
"My method uses a continuous batt of commercially available batt material.",
"The batt is impregnated by conventional methods with a deformable matrix which is typically made from thermoplastic material.",
"Then the batt is cut into mats shaped in an outline of the vehicle floor panel.",
"Placed on the mat, panel or both is a surface-to-surface bonding agent or attachment mechanism.",
"The mat is laid on the panel and facially conformed to the topography of the panel so that the mat and panel are fixed together all over their interface.",
"The bonding agent or attachment mechanism is such that the topographically conformed mat can later be detached by peeling it from the panel.",
"Once the mat is fixed to the panel, the matrix is hardened by cooling.",
"When the matrix hardens, the mat and floor panel reinforce one another and act as an unitized structural member.",
"If one desires to replace the mat, the mat is resoftened by heating and then peeled from the panel, and thereafter a new mat is installed.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a typical vehicle floor panel having superimposed thereon a dashed outline of a fibrous batt unit.",
"FIG. 2 is section taken from line 2--2 in FIG. 1. FIG. 3 is a cross section of a vehicle floor panel and adjoining structure, the panel having a mat fit thereon.",
"FIGS. 4, 5 and 6 are cross sections of a mat on the floor panel.",
"FIGS. 7 and 8 are detail cross sections of optional structures of the mat.",
"FIG. 9 shows a process of mat fabrication and installation.",
"DETAILED DESCRIPTION In FIG. 1 is a typical metal compartment panel 10 which can be a vehicle floor pan.",
"Panel 10 is welded or otherwise fixed to the body (not shown) or frame member 8 (FIG.",
"3) or upright panel 6 of a vehicle.",
"Panel 10 can be some other structural panel such as a roof or side wall, or can be an armor panel.",
"Panel 10 is irregular of shape and non-planar in topography, typically having a pan-like recess 12 and a peripheral ridge 14, although panel 10 may have other topographical features such as corrugations, channels or embossed areas.",
"Shown in dashed lines at 16 is the outline of a section of batt 16 from which a liner mat 18 (FIG.",
"3) is cut for panel 10.",
"Mat 18 is cut so that the mat's peripheral edges will congruently lie along the peripheral edges of panel 10 once mat 18 is fitted thereto.",
"In FIG. 3, for example, mat edges 20 and 22 lie atop corresponding panel edges 24 and 26.",
"FIG. 4 is a detail view of a partial section of mat 18 and underlying panel 10.",
"In that figure, outer surface layer 28 is an optional flexible protective cover for the mat which keeps dirt, oil or other foreign material from harming interior layers of the mat.",
"Interfaced to layer 28 is flexible armor layer 30 having one or any number of sheets comprised of fibers, strands or braided threads of any suitable fibrous material.",
"Such material includes kevlar™ arimid fiber, polymers such as nylon, metal strands, fiberglass or a combination of these materials.",
"The sheets of armor layer 30 act much the same way as layers of a flack jacket to stop bullets or fragments from entering the compartment of which panel 10 is part.",
"The sheets can have a relatively open weave so as to resemble a mesh, or can have a close weave so as to resemble cloth, or else the sheets can have a knitted structure.",
"Permeating layer 30 is a thermoplastic matrix material that impregnates the sheets and occupies any interlaminar space between the sheets.",
"Examples of impregnated, layered structure of layer 30 are in the detailed cross section of FIG. 7. The first example comprises fibrous sheets 32 permeated with the thermoplastic material and having substrata 34 between sheets 32.",
"Substrata 34 are comprised of the thermoplastic material, which is integral or continuous with the thermoplastic material permeating sheets 32.",
"The second example (FIG.",
"7) comprises a series of sheets 32a, 32b, 32c, 32d and 32e that have no interlaminar space therebetween.",
"These latter sheets are also permeated by a thermoplastic material which is continuous with the thermoplastic material of substrata 34.",
"The thermoplastic material is relatively rigid at ambient temperatures.",
"However, this material typically becomes plastically deformable at temperatures higher than maximum passenger compartment temperatures for a military vehicle.",
"Preferably the material becomes plastic at no lower than 150° F. or therabouts and need not be heated above the boiling point of water to become plastically deformable.",
"Once the thermoplastic material softens at the higher temperatures, the sheets of layer 30 can slide relative to one another and relative to layer 28.",
"It may be desired that, at ambient temperatures, the thermoplastic material is less malleable and more brittle than panel 10.",
"The relatively higher brittleness of the thermoplastic material causes the propagation of cracks in the material as panel 10 bends or bulges due to an explosive impact.",
"This propagation will in some instances absorb enough energy from an explosion to save panel 10, whereby mat 18 functions as sacrificial armor.",
"In the case of a relatively high brittleness of the thermoplastic material, it is preferred that at one of the sheets is at the laminar boundaries 60 and 62 (FIG.",
"4) of the matrix material.",
"It is further preferred that at least some of the strands of fibers comprising the sheets of layer 30 be more ductile or malleable than the thermoplastic material.",
"The relatively higher ductility of the fibers will enable them to survive cracking of the thermoplastic material so that the sheets of layer 30 prevent the thermoplastic material from spalling.",
"As an alternative, the thermoplastic material can be replaced by material sensitive to deformation rate.",
"That is, the material is a strain rate sensitive material whose stress-to-strain ratio increases as speed of deformation increases or attempts to increase.",
"Thus the material will rigidify when subjected to high, sudden impacts from explosions but will deform slowly when subjected lower forces for longer periods.",
"Both the rate sensitive material and the thermoplastic material of the mat matrix may be deemed reversibly or impermanently hardenable.",
"That is, these materials can re-soften after hardening.",
"Returning to FIG. 4, there is between mat 18 and panel 10 a stratum 36 by which the mat is fastened to panel 10.",
"Stratum 36 can be simply a layer of adhesive completely covering the area between the mat 18 and panel 10.",
"Stratum 36 can be of the same thermoplastic material as that in layer 30 should that material have adhesive qualities.",
"In such a case, the thermoplastic material of stratum 36 would preferably be integrally continuous with the thermoplastic material of layer 30.",
"Alteratively, stratum 36 can be comprised of one of a well known system of hook-and-loop fasteners such as Velcro™ fasteners.",
"It is contemplated that mat 18 may sometimes be damaged or destroyed by an explosion but panel 10 will survive.",
"Consequently, it may be preferred that stratum 36 allow subsequent removal of mat 18 by applying a relatively light scraping or peeling force, or by the use of solvents.",
"Thereafter a new mat can be installed.",
"Screws, bolts or like fasteners can also be used to fix mat 18 to panel 10, but doing so requires forming the necessary holes in panel 10 and installation of the mat may become overly time consuming.",
"In addition, the bolts, screws or other fasteners will become concentration points for force when panel 10 is subjected to an explosion.",
"Therefore, to counteract the effect of an explosion, a great number of such fasteners will be needed all over panel 10 to keep mat 18 and panel 10 together.",
"FIG. 5 shows another structure for mat 18 wherein the outer surface layer 28 and adhesive stratum 36 are unchanged but the mat's middle layers are modified.",
"Adjacent outer layer 28 in FIG. 5 is an impregnated fibrous layer 38 similar in structure to layer 30.",
"Adjacent stratum 36 is another impregnated fibrous layer 40 which is also similar in structure to layer 30.",
"Between layers 38 and 40 is a layer 42 comprising a matrix of earlier described thermoplastic or rate sensitive material in which are inclusions exemplified at 44.",
"As before, the matrix of layer 42 is integrally continuous with the matrix material of layers 38 and 40.",
"Inclusions 44 are a means to reinforce the mat against puncture by relatively small projectiles such as bullets, mine fragments or flying debris.",
"Inclusions 44 are therefore harder than the matrix material is during its more rigid state.",
"Typically inclusions 44 are made of ceramic material or hardened steel and are bonded or adhered to the surrounding matrix of layer 42.",
"FIG. 6 shows still another structure for mat 18 wherein the outer surface layer 28 and adhesive stratum 36 are unchanged but the mat's middle layer is again modified.",
"In FIG. 6, the middle layer 46 is comprised of a coherent, tomentum-like body of intertangled strands or braided threads.",
"The strands or threads are typically comprised of kevlar™, arimid or like fiber, polymers such as nylon, metal, fiberglass or a mix of these materials.",
"Permeating the tomentum-like body is a matrix of the aforementioned thermoplastic or rate sensitive material having inclusions 44 therein.",
"A layer structured similar to layer 46 may replace either or both of layers 38 and 40 in FIG. 5. Further potential structures of mat mediate layers and combinations of such layers are shown in FIG. 8. There, layer 48 has a matrix 50 of the thermoplastic or rate sensitive material in which run a set of wire-like elements 52.",
"Transverse to wire-like elements 52 is a second set of wire-like elements 54.",
"Elements 52 and 54 may be resistance heating elements for producing heat within mat 18 or they may simply be heat conduction elements that speed transfer of heat into the mat from an external source.",
"Another alternative is layer 56, which is similar in structure to layer 46 except that inclusions 44 are absent from layer 56.",
"Layer 58 is similar to layer 46 except that no fibers or strands are in layer 58.",
"Layers 56 or 58 can be used as additional mediate mat layers in the FIG. 5 embodiment;",
"in the alternative, layers 56 or 58 can replace one or more of layers 38, 40 or 42 in FIG. 5. FIG. 9 illustrates one process by which mats 18 would be fabricated and installed in existing military vehicles.",
"The first step in this process is simply the conventional manufacture of a continuous batt 64.",
"The fibrous material of batt 64 is configured similarly to the fibrous material of layer 30 in FIG. 4. Batt 64 is impregnated with a thermoplastic matrix material so as to have the cross sectional batt structure shown at 66 and similar to layer 30.",
"Batt structure 66 optionally has outer surface layer 28 placed thereon after impregnation of the fibrous material.",
"The continuous batts are then cut into flat rectangular blanks 70 and thereafter trimmed to an outline 72 of the vehicle compartment panel.",
"Next, the trimmed rectangular blanks, which can be regarded now as mats 18, are shipped to world wide locations such as U S Army depots or marshalling yards, designated by reference numeral 68.",
"After shipping, mats 18 are heated in oven 74 or by other suitable means to soften the thermoplastic matrix material.",
"After being heated, mat 18 is then laid upon panel 10 and conformed to the topography thereof, both the fibrous material and matrix material deforming to match the shape of panel 10.",
"Then mat 18 is allowed to harden and cool.",
"Prior to the laying of mat 18 on panel 10, adhesive can be applied to the panel or the mat, the adhesive bonding the mat to the panel after the mat cools.",
"As noted before, mechanical devices can be used to fix mat 18 to panel 10, these devices including threaded fasteners, clamps or hook-and-loop fasteners.",
"In the case where the mat's matrix material is strain rate sensitive, the heating of mat 18 is omitted.",
"I wish it to be understood that I do not desire to be limited to the exact details of construction or method shown herein since obvious modifications will occur to those skilled in the relevant arts without departing from the spirit and scope of the following claims."
] |
BACKGROUND AND SUMMARY OF THE INVENTION
This invention pertains to sidewalk grooving tools of the type disclosed in my previous U.S. Pat. No. 4,921,372, issued May 1, 1990,and more particularly to such a tool which has handles that fold down adjacent to the blade for relatively easier storage and transport.
The tool shown in my previous patent noted above operates very satisfactorily in that it allows a worker to stand adjacent the sidewalk and groove the walk. However, because the grips and guide bar extend transversely to the principle blade; and because the handles are fixed at an angle to the blade, the device is rather clumsy to store either while not in use or while being transported.
By the present invention, I provide for a tool in which the handles fold down to the blade to provide for a compact unit which may be placed in a relatively small space so that storage is made much simpler and easier.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the tool as assembled for use, and
FIG. 2 is a similar view of the tool folded for storage, and
FIG. 3 is a partial view of the end of the bar showing an alternate cross section.
DESCRIPTION
Briefly, this invention is an improvement in the sidewalk grooving tool of my previous invention patented as U.S. Pat. No. 4,921,372 on May 1, 1990 which comprises a pair of folding handles which lie along the grooving bar and are held in that position by simple holding means.
More specifically and referring to the drawings, the tool operates to scribe a sidewalk using a scribing bar 10 which may have the cross section of an angle iron as illustrated, or may be of T-shaped cross section. One flange 11 of the bar is adapted to be pressed into soft concrete to form the scribed line common in all sidewalks. The cross flange 12 provides a gage to control the depth of the groove. The T-shape as shown in FIG. 3 may be preferred by some because the cross flange 12' extends on both sides of the vertical or scribing flange 11'.
A cross member 13 at one end of the bar 10 forms a T with that bar and serves as a guide to be set against the form defining the edge of the sidewalk. In this way, the direction of the groove in the walk can be reasonably certain to be perpendicular to the edge of the walk.
To use the device, a couple of handles extending upward from the bar 10 allow a worker to stand alongside the walk and press the bar into the unhardened concrete. In the original device, the handles were welded or otherwise fixed to the bar and worked well in use. The problem encountered was in storage.
In the present device, there are two handles. A first handle 15 is pivoted to the cross member 13 by a hinge-like device 16 so that the handles can be readily pivoted through about 180 degrees of movement. A grip 17 is provided so that the operator can press the device into the concrete. On the handle spaced somewhat closer to the grip 17 than to the hinge 16, is a loop 18 for a purpose to be described later.
The second handle 20 is pivoted to the top of the bar 10 at a hinge 21 spaced substantially from the cross member 13. This handle also has a grip at the end opposite to the hinge 21 so that the position of the blade 10 can be guided and pressed into the concrete.
As shown in FIG. 1, when in use the handles 15 and 20 are crossed in a triangular shape so that both grips 17 and 22 are substantially carried above the bar 10. The handles are retained in that position by the engagement between a pin 24 and the ring 18. The pin 24 is fixed to the second handle 20 by welding or the like and extends laterally from that handle so that it can extend through the ring. It should be noted that there is sufficient spring flexibility in the handles that the pin 24 may be readily disengaged from the ring 18. However, for use, the bias of the spring action in the handles is to press the handles together so that the pin 24 and ring 18 stay engaged.
In order to fold the tool, the handles are sprung to disengage the pin 24. The handle 20 is the then moved around the grip 17 on the handle 15 to a position behind the handle 15 as shown in dashed lines in FIG 1. From this position, the blade 10 can be pulled upward by pulling the handle 20 until the handles 15 and 20 lie substantially alongside the blade 10. Although FIG. 2 shows the tool lying flat for storage, the relative position of the handles and the bar are as they would be if pulled to a vertical position as described. It should be noted that the grip 17 on the handle 15 is now between the blade 10 and the handle 20 and is thus held in place. To facilitate achieving this position, the handle 20 should be slightly bent at 27 to accommodate the grip 17.
In order to keep the tool in the folded position, a ring 28 is fixed to the blade in position to be engaged by the pin 24, and again the springiness of the handle 20 and the direction of bias of springiness makes the engagement and holding of the engagement possible.
From the above description, the usefulness of the improvement will be obvious. In use, the grips 17 and 22 are in position for a worker, while standing, to press the blade into the soft concrete. To fold the tool, the workers sets his foot against the cross member 13, disengages the pin 24 from the ring 18 and while pulling the blade 10 upward, moves the handle 20 around the grip 17. Further pulling the blade 10 to an upright position results in the juxtaposition of the two handles 15 and 20 with the blade 10 as shown in FIG 2. At this point, the pin 24 can be engaged with the ring 28 to hold the tool folded together to then be laid down in a pickup or other truck to be transported to the next job site. | An improved sidewalk grooving tool usable by a standing worker but having foldable handles for flat storage and transport. | Identify the most important aspect in the document and summarize the concept accordingly. | [
"BACKGROUND AND SUMMARY OF THE INVENTION This invention pertains to sidewalk grooving tools of the type disclosed in my previous U.S. Pat. No. 4,921,372, issued May 1, 1990,and more particularly to such a tool which has handles that fold down adjacent to the blade for relatively easier storage and transport.",
"The tool shown in my previous patent noted above operates very satisfactorily in that it allows a worker to stand adjacent the sidewalk and groove the walk.",
"However, because the grips and guide bar extend transversely to the principle blade;",
"and because the handles are fixed at an angle to the blade, the device is rather clumsy to store either while not in use or while being transported.",
"By the present invention, I provide for a tool in which the handles fold down to the blade to provide for a compact unit which may be placed in a relatively small space so that storage is made much simpler and easier.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the tool as assembled for use, and FIG. 2 is a similar view of the tool folded for storage, and FIG. 3 is a partial view of the end of the bar showing an alternate cross section.",
"DESCRIPTION Briefly, this invention is an improvement in the sidewalk grooving tool of my previous invention patented as U.S. Pat. No. 4,921,372 on May 1, 1990 which comprises a pair of folding handles which lie along the grooving bar and are held in that position by simple holding means.",
"More specifically and referring to the drawings, the tool operates to scribe a sidewalk using a scribing bar 10 which may have the cross section of an angle iron as illustrated, or may be of T-shaped cross section.",
"One flange 11 of the bar is adapted to be pressed into soft concrete to form the scribed line common in all sidewalks.",
"The cross flange 12 provides a gage to control the depth of the groove.",
"The T-shape as shown in FIG. 3 may be preferred by some because the cross flange 12'",
"extends on both sides of the vertical or scribing flange 11'.",
"A cross member 13 at one end of the bar 10 forms a T with that bar and serves as a guide to be set against the form defining the edge of the sidewalk.",
"In this way, the direction of the groove in the walk can be reasonably certain to be perpendicular to the edge of the walk.",
"To use the device, a couple of handles extending upward from the bar 10 allow a worker to stand alongside the walk and press the bar into the unhardened concrete.",
"In the original device, the handles were welded or otherwise fixed to the bar and worked well in use.",
"The problem encountered was in storage.",
"In the present device, there are two handles.",
"A first handle 15 is pivoted to the cross member 13 by a hinge-like device 16 so that the handles can be readily pivoted through about 180 degrees of movement.",
"A grip 17 is provided so that the operator can press the device into the concrete.",
"On the handle spaced somewhat closer to the grip 17 than to the hinge 16, is a loop 18 for a purpose to be described later.",
"The second handle 20 is pivoted to the top of the bar 10 at a hinge 21 spaced substantially from the cross member 13.",
"This handle also has a grip at the end opposite to the hinge 21 so that the position of the blade 10 can be guided and pressed into the concrete.",
"As shown in FIG. 1, when in use the handles 15 and 20 are crossed in a triangular shape so that both grips 17 and 22 are substantially carried above the bar 10.",
"The handles are retained in that position by the engagement between a pin 24 and the ring 18.",
"The pin 24 is fixed to the second handle 20 by welding or the like and extends laterally from that handle so that it can extend through the ring.",
"It should be noted that there is sufficient spring flexibility in the handles that the pin 24 may be readily disengaged from the ring 18.",
"However, for use, the bias of the spring action in the handles is to press the handles together so that the pin 24 and ring 18 stay engaged.",
"In order to fold the tool, the handles are sprung to disengage the pin 24.",
"The handle 20 is the then moved around the grip 17 on the handle 15 to a position behind the handle 15 as shown in dashed lines in FIG 1.",
"From this position, the blade 10 can be pulled upward by pulling the handle 20 until the handles 15 and 20 lie substantially alongside the blade 10.",
"Although FIG. 2 shows the tool lying flat for storage, the relative position of the handles and the bar are as they would be if pulled to a vertical position as described.",
"It should be noted that the grip 17 on the handle 15 is now between the blade 10 and the handle 20 and is thus held in place.",
"To facilitate achieving this position, the handle 20 should be slightly bent at 27 to accommodate the grip 17.",
"In order to keep the tool in the folded position, a ring 28 is fixed to the blade in position to be engaged by the pin 24, and again the springiness of the handle 20 and the direction of bias of springiness makes the engagement and holding of the engagement possible.",
"From the above description, the usefulness of the improvement will be obvious.",
"In use, the grips 17 and 22 are in position for a worker, while standing, to press the blade into the soft concrete.",
"To fold the tool, the workers sets his foot against the cross member 13, disengages the pin 24 from the ring 18 and while pulling the blade 10 upward, moves the handle 20 around the grip 17.",
"Further pulling the blade 10 to an upright position results in the juxtaposition of the two handles 15 and 20 with the blade 10 as shown in FIG 2.",
"At this point, the pin 24 can be engaged with the ring 28 to hold the tool folded together to then be laid down in a pickup or other truck to be transported to the next job site."
] |
TECHNICAL FIELD
[0001] The present invention relates to a disconnection detection circuit for a bridge circuit, or more particularly, to a disconnection detection circuit for a bridge circuit that little affects an output voltage of a bridge circuit.
BACKGROUND ART
[0002] Existing examples of a disconnection detection circuit for a bridge circuit include a sensor bridge circuit described in Japanese Unexamined Patent Application Publication No. Hei6-249730.
CITATION LIST
Patent Literature
[0003] Patent literature 1: Japanese Unexamined Patent Application Publication No. Hei6-249730
SUMMARY OF INVENTION
Technical Problem
[0004] An existing technology described in Japanese Unexamined Patent Application Publication No. Hei6-249730 is such that: as shown in FIG. 2 , resistors 19 and 20 are connected to outputs of a bridge circuit composed of sensor element resistors 15 , 16 , 17 , and 18 , and to a power supply and a ground respectively; when the output of the bridge circuit is disconnected, an output voltage of the bridge circuit is largely varied; and a sensor output obtained by amplifying the output voltage of the bridge circuit using an amplifier 21 is largely varied so that the fact that the bridge circuit has been disconnected can be detected.
[0005] However, in the foregoing disconnection detection circuit, consideration is not taken into the fact that since the resistors 19 and 20 are asymmetrically connected in parallel with the sensor bridge, an offset voltage or temperature characteristic of the sensor is degraded.
[0006] The present invention addresses the foregoing situation. An object of the present invention is to provide a disconnection detection circuit for a bridge circuit which suppresses a change in a characteristic of a sensor to a minimalextent.
Solution to Problem
[0007] In order to solve the aforesaid problem, a current is caused to flow from an output terminal of a bridge circuit to a predetermined potential, a potential difference between the potential at the output terminal of the bridge circuit and the predetermined potential is detected, and a disconnection is detected based on the potential difference.
Advantageous Effects of Invention
[0008] According to the present invention, an adverse effect which a disconnection detection circuit imposes on an output voltage of a sensor bridge circuit can be reduced. Therefore, an offset voltage or temperature characteristic of a sensor bridge output can be improved, and the disconnection of the sensor bridge can be highly precisely detected. Eventually, a highly precise and highly reliable sensor can be provided.
BRIEF DESCRIPTION OF DRAWINGS
[0009] FIG. 1 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a first embodiment;
[0010] FIG. 2 is a diagram showing a disconnection detection circuit for a bridge circuit of an existing technology;
[0011] FIG. 3 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a second embodiment;
[0012] FIG. 4 is a diagram showing a drain current characteristic of transistors 24 and 25 ;
[0013] FIG. 5 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a third embodiment;
[0014] FIG. 6 is a timing chart of control signals for switches 26 , 28 , 29 , 30 , 31 , and 32 ;
[0015] FIG. 7 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a fourth embodiment;
[0016] FIG. 8 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a fifth embodiment;
[0017] FIG. 9 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a sixth embodiment;
[0018] FIG. 10 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a seventh embodiment;
[0019] FIG. 11 is a configuration diagram of a system of an eighth embodiment including a disconnection detecting means;
[0020] FIG. 12 is a configuration diagram of a system of a ninth embodiment including a disconnection detecting means; and
[0021] FIG. 13 is a configuration diagram of a system of a tenth embodiment including a disconnection detecting means.
DESCRIPTION OF EMBODIMENTS
[0022] Now, referring to FIG. 1 to FIG. 13 , embodiments of the present invention will be described below.
[0023] To begin with, a disconnection detection circuit for a bridge circuit that is a first embodiment of the present invention will be described in conjunction with FIG. 1 . FIG. 1 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the first embodiment.
[0024] A detection element 1 is formed with a bridge circuit having a series circuit composed of sensor element resistors 2 and 4 and series resistors, which include sensor element resistors 3 and 5 , connected in parallel with each other. When the resistance values of the sensor element resistors 2 , 3 , 4 , and 5 vary depending on a measurement physical quantity, an intermediate voltage between the sensor element resistors 2 and 4 and an intermediate voltage between the sensor element resistors 3 and 5 vary. Incidentally, the intermediate voltage between the sensor element resistors 3 and 5 is inputted to an output terminal A, and fetched into outside of the detection element 1 through the output terminal A. The intermediate voltage between the sensor element resistors 2 and 4 is inputted to an output terminal B, and fetched into outside of the detection element 1 through the output terminal B. An output voltage (a voltage between the output terminals A and B) of the bridge circuit fetched through the output terminal A and output terminal B is amplified by an amplifier 6 , and outputted to outside as a sensor output via a switching circuit 7 . For the sensor element resistors, for example, platinum (Pt), tantalum (Ta), molybdenum (Mo), or silicon (Si) is selected.
[0025] A disconnection detection circuit 8 a includes a resistor 10 that causes a current to flow into the output terminal A, a resistor 9 that causes a current to flow into the output terminal B, a reference voltage source 11 that regenerates a reference voltage, a comparator 12 that compares the voltage at the output terminal A with the voltage at the reference voltage source 11 so as to detect the disconnection of the output terminal A, a comparator 13 that compares the voltage at the output terminal B with the voltage at the reference voltage source 11 so as to detect the disconnection of the output terminal B, and an OR circuit 14 that obtains an OR of the comparator 12 and comparator 13 . If the disconnection detection circuit 8 a detects a disconnection, the switching circuit 7 fixes the sensor output to a ground voltage or a supply voltage.
[0026] Next, actions of the disconnection detection circuit 8 a will be described. The disconnection detection circuit 8 a detects the disconnections of the output terminal A and output terminal B.
[0027] If the output terminal A is disconnected, the potential at the output terminal A is brought to a ground potential by the resistor 10 . The potential at the output terminal A is compared with the voltage at the reference voltage source 11 by the comparator 12 . When the output terminal A is disconnected, the disconnection is reflected on the output of the comparator 12 .
[0028] If the output terminal B is disconnected, the potential at the output terminal B is brought to the ground potential by the resistor 9 . The potential at the output terminal B is compared with the voltage at the reference voltage source 11 by the comparator 13 . When the output terminal B is disconnected, the disconnection is reflected on the output of the comparator 13 .
[0029] Therefore, if the output terminal A or output terminal B is disconnected, the disconnection is reflected on the output of the OR circuit that obtains the OR of the outputs of the comparators 12 and 13 . Owing to the constitution, the disconnection detection circuit 8 can detect the disconnections of the output terminal A and output terminal B.
[0030] Next, the features of the disconnection detection circuit 8 a of the present embodiment will be described below. The disconnection detection circuit 8 a is a circuit that is symmetrical with respect to the output terminals A and B of the bridge circuit of the detection element 1 , whereby an adverse effect on an output voltage of the bridge circuit of the detection element 1 can be minimized. Specifically, a circuit to be connected to the output terminal A includes the resistor 10 and comparator 12 , and a circuit to be connected to the output terminal B includes the resistor 9 and comparator 13 . Thus, since the identical circuits are connected to the respective output terminals, adverse effects which the disconnection detection circuit 8 a imposes on the output terminal A and output terminal B respectively are identical to each other. Accordingly, an adverse effect on the output voltage of the bridge circuit of the detection element 1 (a difference voltage between the output terminal A and output terminal B) can be reduced.
[0031] Next, a disconnection detection circuit for a bridge circuit that is a second embodiment of the present invention will be described in conjunction with FIG. 3 and FIG. 4 . Incidentally, FIG. 3 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the second embodiment, and FIG. 4 is a diagram showing a drain current characteristic of transistors 24 and 25 . The disconnection detection circuit for a bridge circuit of the second embodiment is such that the resistors 9 and 10 of the disconnection detection circuit for a bridge circuit of the first embodiment are changed into a current mirror circuit composed of transistors 23 , 24 , and 25 .
[0032] In the disconnection detection circuit 8 b for a bridge circuit of the present embodiment, the resistors 9 and 10 are changed into a current mirror circuit composed of the transistors 23 , 24 , and 25 . A constant current source 22 is connected to the transistor 23 , so that the drain currents of the transistors 24 and 25 exhibit a characteristic shown in FIG. 4 . Accordingly, when the output terminals A and B are not disconnected, the impedances of the transistors 24 and 25 with respect to the output terminals A and B can be raised. Therefore, an adverse effect on the output voltage of the bridge circuit can be further reduced.
[0033] When the disconnection of the output terminal A or output terminal B is detected, the impedance of the transistor 24 or 25 with respect to the output terminal A or B can be diminished. Therefore, since the voltage at the disconnected output terminal A or B can be dropped, a margin of a threshold for the comparator 12 or 13 can be increased. Eventually, precision in disconnection detection can be improved.
[0034] Next, a disconnection detection circuit for a bridge circuit of a third embodiment of the present invention will be described in conjunction with FIG. 5 and FIG. 6 . FIG. 5 is a circuit diagram of the disconnection detection circuit for abridge circuit of the third embodiment, and FIG. 6 is a timing chart of control signals for switches 26 , 28 , 29 , 30 , 31 , and 32 . The third embodiment is such that the switches 26 , 28 , 29 , 30 , 31 , and 32 and capacitors 27 , 33 , and 34 are added to the first embodiment.
[0035] In the present embodiment, the switches 26 , 28 , 29 , 30 , 31 , and 32 and capacitors 27 , 33 , and 34 are added so that detection of a bridge voltage and disconnection detection can be executed in time-sharing manner. Specifically, at timing P 1 , the switches 26 and 30 are made in order to connect the output terminals A and B to the amplifier 6 , whereby the output voltage of the bridge circuit is detected. At this time, the switches 28 and 29 enter a broken state. Therefore, the disconnection detection circuit 8 c does not affect the output voltage of the bridge circuit because the bridge circuit is completely disconnected from the disconnection detection circuit 8 c . The capacitor 27 is included to hold the voltage at the timing P 1 in preparation for the timing P 2 when the switches 26 and 30 are broken.
[0036] Thereafter, the switches 28 , 29 , 31 , and 32 are made at the timing P 2 in order to connect the output terminals A and B to the disconnection detection circuit 8 c , whereby the disconnection of the output terminal A or B of the bridge circuit is detected. At this time, the switches 26 and 30 are left broken and completely disconnected from the amplifier 6 . Therefore, an input resistance of the amplifier 6 does not affect the disconnection detection circuit 8 . The capacitors 33 and 34 are included to hold the voltages attained at the timing P 2 in preparation for the timing P 1 when the switches 28 , 29 , 31 , and 32 are broken.
[0037] Next, a disconnection detection circuit for a bridge circuit that is a fourth embodiment of the present invention will be described in conjunction with FIG. 7 . FIG. 7 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the fourth embodiment.
[0038] To begin with, a detection element 35 is a half bridge circuit composed of sensor element resistors 36 and 37 . When the sensor element resistors 36 and 37 vary depending on a measurement physical quantity, a voltage at an output terminal of the bridge circuit is varied. An output voltage of the half bridge circuit is amplified by an amplifier 39 and outputted to outside as a sensor output. A supply voltage Vcc is connected to a power terminal of the bridge circuit, and a predetermined voltage is fed to a ground terminal via a reference voltage source 38 . A disconnection detection circuit 41 includes a constant current source 42 that feeds a current to the output terminal of the half bridge circuit, a reference voltage source 43 that generates a reference voltage, and a comparator 44 that compares a voltage at the output terminal of the half bridge circuit with the value of the reference voltage source 43 so as to detect the disconnection of the output terminal. If the disconnection detection circuit 41 detects a disconnection, a switching circuit 40 fixes the sensor output to a ground voltage or supply voltage.
[0039] Next, actions of the disconnection detection circuit will be described below. The disconnection detection circuit detects the disconnection of the output terminal of the half bridge circuit. To begin with, if the output terminal is disconnected, the potential at the output terminal is brought to a ground potential by the constant current source 42 . The potential at the output terminal is compared with the voltage of the reference voltage source 43 by the comparator 44 . Therefore, if the output terminal is disconnected, the disconnection is reflected on the output of the comparator 44 . Thus, the disconnection detection circuit 41 detects the disconnection of the output terminal.
[0040] Next, the features of the disconnection detection circuit will be described below. Assuming that the sensor element resistor 36 is a component whose resistance varies, like a thermistor, by several digits depending on temperature, the voltage at the output terminal changes from near the voltage at the power terminal of the detection element 35 to near the voltage at the ground terminal.
[0041] Assuming that the voltage at the ground voltage is 0 V, when the disconnection of the output terminal has to be reliably detected, it is necessary to increase the current of the constant current source 42 and to set the voltage of the reference voltage source 43 to almost 0 V. This is because, since the output of the detection element 35 at a normal time changes from near the voltage at the power terminal of the detection element 35 to near the voltage at the ground terminal, it is necessary to bring the voltage at a disconnection time to a voltage that falls outside the output at the normal time, and to bring the voltage of the reference voltage source 43 , which is a voltage to be compared by the comparator 44 , to the voltage that falls outside the output at the normal time. Therefore, in order to reliably bring the voltage at the disconnection time to the voltage that falls outside the output at the normal time, that is, in order to bring the voltage to almost 0 V, it is necessary to increase the current of the constant current source 42 and to bring a comparison voltage of the comparator 44 to near almost 0 V. However, when the current of the constant current source 42 is increased, an adverse effect on a sensor output is intensified. When the voltage of the reference voltage source is brought to almost 0 V, a margin of a threshold for the comparator 44 nearly runs out. Eventually, precision in disconnection detection is degraded.
[0042] In the present embodiment, as a voltage at a ground terminal of the detection element 35 , a voltage of several volts is applied using the reference voltage source 38 . In this case, even if the sensor element resistor 36 is a component whose resistance varies, like a thermistor, by several digits depending on temperature, the voltage at the output terminal changes merely from a voltage at a power terminal of the detection element 35 to the voltage of the reference voltage source 38 that is the voltage at the ground terminal. Therefore, the current of the constant current source 42 can be diminished because it should merely be equal to or lower than the voltage of the reference voltage source 38 at the disconnection time of the output terminal of the detection element 35 . In addition, since the voltage of the reference voltage source 43 that is a reference value for disconnection detection can be set to the voltage of the reference voltage source 38 , the margin of the threshold for the comparator 44 can be increased. Eventually, precision in disconnection detection can be improved.
[0043] Next, a disconnection detection circuit for a bridge circuit which is a fifth embodiment of the present invention will be described in conjunction with FIG. 8 . FIG. 8 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the fifth embodiment. Incidentally, the disconnection detection circuit for a bridge circuit of the fifth embodiment is, contrary to the disconnection detection circuit for a bridge circuit of the fourth embodiment, such that a voltage at a power terminal of a detection element 35 is dropped by several volts using a reference voltage source 45 .
[0044] To begin with, the detection element 35 is a half bridge circuit composed of sensor element resistors 36 and 37 . The sensor element resistors 36 and 37 vary depending on a measurement physical quantity, whereby a voltage at an output terminal of the bridge circuit is varied. The output voltage of the bridge circuit is amplified by an amplifier 39 and outputted to outside as a sensor output. A power terminal of the bridge circuit is connected to a supply voltage Vcc via a reference voltage source 45 . A voltage that is lower than the supply voltage Vcc by the voltage of the reference voltage source 45 is fed to the power terminal. A ground terminal is provided with a ground potential. A disconnection detection circuit 46 includes a constant current source 47 that feeds a current into the output terminal, a reference voltage source 48 that generates a reference voltage, and a comparator 49 that compares the voltage at the output terminal with the value of the reference voltage source 48 so as to detect the disconnection of the output terminal. If the disconnection detection circuit 46 detects a disconnection, a switching circuit 40 fixes the sensor output to a ground voltage or supply voltage.
[0045] Next, actions of the disconnection detection circuit will be described below. The disconnection detection circuit detects the disconnection of the output terminal. If the output terminal is disconnected, the potential at the output terminal is brought to the supply voltage by the constant current source 47 . The potential at the output terminal is compared with the voltage of the reference voltage source 48 by the comparator 49 . Therefore, if the output terminal is disconnected, the disconnection is reflected on the output of the comparator 49 . Accordingly, the disconnection detection circuit 46 detects the disconnection of the output terminal.
[0046] Next, the features of the disconnection detection circuit will be described below. When the sensor element resistor 36 is, like a thermistor, a component whose resistance value varies by several digits depending on temperature, the voltage at the output terminal changes from the voltage at the power terminal of the detection element 35 to the voltage at the ground terminal. Assume that the voltage at the power terminal is equal to the supply voltage Vcc. In this case, for reliably detecting the disconnection of the output terminal, it is necessary to increase the current of the constant current source 47 and to set the voltage of the reference voltage source 48 to almost the supply voltage Vcc. However, when the current of the constant current source 47 is increased, an adverse effect on the sensor output is intensified. When the voltage of the reference voltage source 48 is set to almost the supply voltage Vcc, a margin of a threshold for the comparator 49 nearly runs out. Therefore, precision in disconnection detection is degraded.
[0047] In the present embodiment, the reference voltage source 45 is used to drop the voltage at the power terminal of the detection element 35 so that the voltage becomes lower than the supply voltage Vcc by several volts. In this case, even if the sensor element resistor 36 is, like a thermistor, a component whose resistance value varies by several digits depending on temperature, the voltage at the output terminal merely changes from a voltage, which is lower by several volts than the supply voltage that is equal to the voltage at the power terminal of the detection element 35 , to the ground voltage. Therefore, the current of the constant current source 47 can be diminished because when the output terminal of the detection element 35 is disconnected, the voltage at the power supply should merely approach the supply voltage with a margin equivalent to the voltage of the reference voltage source 45 . In addition, the voltage of the reference voltage source 48 that is a reference value for disconnection detection can be set with a margin equivalent to the voltage of the reference voltage source 45 . Therefore, the margin of the threshold for the comparator 49 can be increased. Eventually, precision in disconnection detection can be improved.
[0048] Next, a disconnection detection circuit for a bridge circuit that is a sixth embodiment of the present invention will be described below in conjunction with FIG. 9 . FIG. 9 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the sixth embodiment.
[0049] To begin with, a detection element 50 is a bridge circuit composed of sensor element resistors 51 , 52 , 53 , and 54 . The sensor element resistors 51 , 52 , 53 , and 54 vary depending on a measurement physical quantity, whereby voltages at output terminals A and B of the bridge circuit are varied. An output voltage of the bridge circuit (a voltage between the output terminals A and B) is analog-to-digital converted by a delta-sigma modulator 55 (hereinafter, a ΔΣ modulator), and outputted to outside as a sensor output. Incidentally, the ΔΣ modulator 55 includes an SC integrator that is composed of switches 56 , 58 , 63 , and 65 which act at the timing P 1 shown in FIG. 6 , switches 59 , 60 , 61 , and 62 which act at the timing P 2 shown in FIG. 6 , capacitors 57 , 64 , 66 , and 68 , and an amplifier 67 , a comparator 69 that compares the output of the SC integrator, a local digital-to-analog (D/A) converter 70 that outputs a voltage according to the output of the comparator 69 . A disconnection detection circuit 72 includes a switch 74 that acts at the timing P 2 shown in FIG. 6 so as to link the output terminal A and a constant current source 76 , a switch 73 that acts at the timing P 2 shown in FIG. 6 so as to link the output terminal B and a constant current source 75 , the constant current source 76 that feeds a current into the output terminal A, the constant current source 75 that feeds a current into the output terminal B, a sample-and-hold circuit that samples voltages across the constant current sources 75 and 76 at the timing P 2 shown in FIG. 6 and is composed of switches 77 and 78 and capacitors 79 and 80 , a reference voltage source 81 that generates a reference voltage, a comparator 82 that compares a voltage across the capacitor 79 with the value of the reference voltage source 82 so as to detect the disconnection of the output terminal A, a comparator 83 that compares a voltage across the capacitor 80 with the value of the reference voltage source 81 so as to detect the disconnection of the output terminal B, and an OR circuit 84 that obtains an OR of the comparator 82 and comparator 83 . In addition, there is an AND circuit 71 that, if the disconnection detection circuit 72 detects a disconnection, fixes the output of the ΔΣ modulator 55 to a ground.
[0050] Next, actions of the present embodiment will be described below. The ΔΣ modulator 55 discharges the capacitors 57 and 64 at the timing P 2 . At the timing P 1 , the ΔΣ modulator 55 samples the output voltage of the bridge circuit and charges the capacitors using the SC integrator. The disconnection detection circuit 72 acts at the timing P 2 , which is a non-sampling period of the ΔΣ modulator 55 , so as not to affect the action of the ΔΣ modulator 55 . The disconnection detection circuit 72 turns on the switches 73 , 74 , 77 , and 78 at the timing P 2 so that a constant current flows into the output terminals A and B of the bridge circuit. At this time, if the output terminal A or output terminal B is disconnected, the voltage across the associated constant current source 75 or 76 is dropped to almost a ground potential. The voltage is held by the sample-and-hold circuit including the switches 77 and 78 and capacitors 79 and 80 , and compared by the comparator 82 or 83 , whereby the disconnection of the output terminal A or B is detected.
[0051] Next, the features of the present embodiment will be described below. Since the disconnection detection circuit 72 is a circuit symmetrical with respect to the output terminals A and B of the bridge circuit of the detection element 50 , an adverse effect on the output voltage of the bridge circuit of the detection element 50 can be minimized.
[0052] Since the disconnection detection circuit 72 acts during the non-sampling period of the ΔΣ modulator 55 , the action of the disconnection detection circuit 72 does not affect the ΔΣ modulator 55 . In reverse, the action of the ΔΣ modulator 55 does not affect the disconnection detection circuit 72 .
[0053] When the ΔΣ modulator 55 is employed in a detection circuit for an output voltage of a bridge circuit, it is very easy to fix an output signal to a value that cannot be outputted as an ordinary sensor output because an AND circuit alone is needed.
[0054] Next, a disconnection detection circuit for a bridge circuit that is a seventh embodiment of the present invention will be described in conjunction with FIG. 10 . FIG. 10 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the seventh embodiment. The present embodiment is such that the constant current sources 75 and 76 of the sixth embodiment are replaced with a switched capacitor circuit composed of switches 85 and 87 and capacitors 86 and 88 .
[0055] In the present embodiment, faster detection than that achieved using the constant current sources 75 and 76 is enabled by replacing the constant current sources 75 and 76 with a switched capacitor circuit. This is because the switched capacitor circuit provides less impedance than the constant current sources do. This makes it possible to speed up an operating clock for the ΔΣ modulator 55 . Eventually, precision of the ΔΣ modulator 55 and responsiveness thereof can be improved.
[0056] Next, a system that is an eighth embodiment of the present invention and includes a disconnection detecting means will be described in conjunction with FIG. 11 . FIG. 11 is a configuration diagram of the system of the eighth embodiment including the disconnection detecting means.
[0057] The present embodiment includes an airflow sensor 89 that detects an air flow rate Q, an intake air temperature sensor 90 that detects intake air temperature Ta, a disconnection detector 91 that detects the disconnection of the intake air temperature sensor 90 , a correction circuit 92 that corrects the air flow rate Q, which is an output signal of the airflow sensor 89 , with the intake air temperature Ta that is an output signal of the intake air temperature sensor 90 , and a switching circuit 93 that, if the disconnection detector 91 detects a disconnection, fixes the signal of the intake air temperature Ta, which is handed to the correction circuit 92 , to 25° C.
[0058] The present embodiment is the system in which if the intake air temperature sensor 90 is disconnected and outputs the signal having an extremely large error, the correction circuit 92 is prevented from performing excess correction processing and outputting a signal, which has an extremely large error, as a sensor output (air flow rate signal). In the present embodiment, if the intake air temperature sensor 90 is disconnected, the switching circuit 93 fixes the signal of the intake air temperature Ta, which is fed to the correction circuit 92 , to 25° C. Thus, excessive correction is prevented. Accordingly, even if the intake air temperature sensor 90 is disconnected, an error in the sensor output can be suppressed. In particular, as far as an airflow sensor that measures an intake air flow rate of an automobile is concerned, if an error caused by the airflow sensor is large, a fatal phenomenon that an engine is not started takes place. In particular, such an event must be avoided that although the airflow sensor 89 does not fail, the sensor output becomes extremely abnormal because of the failure of the intake air temperature sensor 90 . The present system can avoid the event.
[0059] Next, a system that is a ninth embodiment of the present invention and includes a disconnection detecting means will be described in conjunction with FIG. 12 . FIG. 12 is a configuration diagram of the system of the ninth embodiment including the disconnection detecting means. The present embodiment is a system that includes the disconnection detecting means and has the switching circuit 93 , which is included in the system of the eighth embodiment including the disconnection detecting means, changed into a switching circuit 94 .
[0060] In the present embodiment, the switching circuit 93 is changed into the switching circuit 94 . If the intake air temperature sensor is disconnected, the correction circuit 92 is bypassed in order to prevent excessive correction. Thus, even if the intake air temperature sensor 90 is disconnected, an error in the sensor output can be suppressed.
[0061] Next, a system that is a tenth embodiment of the present invention and includes a disconnection detecting means will be described in conjunction with FIG. 13 . FIG. 13 is a configuration diagram of the system of the tenth embodiment including the disconnection detecting means. The present embodiment is a system that includes the disconnection detecting means, has a circuit temperature sensor 95 added to the system of the eighth embodiment including the disconnection detecting means, and has a switching destination at a disconnection time by the switching circuit 93 changed to another.
[0062] In the present embodiment, the circuit temperature sensor 95 is added, and the switching destination at a disconnection time by the switching circuit 93 is changed to another. If the intake air temperature sensor is disconnected, the switching destination of the correction circuit 92 is set to the circuit temperature sensor 95 in order to prevent excessive correction. This is attributable to the fact that in a steady state, there is no large difference between the intake air temperature Ta and circuit temperature Tlsi. Accordingly, even if the intake air temperature sensor 90 is disconnected, an error in the sensor output can be suppressed.
LIST OF REFERENCE SIGNS
[0000]
1 , 35 , 50 : detection element
2 , 3 , 4 , 5 , 15 , 16 , 17 , 18 , 36 , 37 , 51 , 52 , 53 , 54 : sensor element resistor
6 , 21 , 39 , 67 : amplifier
7 , 40 , 93 , 94 : switching circuit
8 , 8 a , 8 b , 8 c , 41 , 46 : disconnection detection circuit
9 , 10 , 19 , 20 : resistor
11 , 38 , 43 , 45 , 58 , 81 : reference voltage source
12 , 13 , 44 , 49 , 69 , 82 , 83 : comparator
14 , 84 : OR circuit
22 , 42 , 47 , 75 , 76 : constant current source
23 , 24 , 25 : transistor
26 , 28 , 29 , 30 , 31 , 32 , 56 , 58 , 59 , 60 , 61 , 62 , 63 , 65 , 73 , 74 , 77 , 78 , 85 , 87 : switch
27 , 33 , 34 , 57 , 64 , 66 , 68 , 79 , 80 , 86 , 88 : capacitor
55 : ΔΣ modulator
70 : local D/A converter
71 : AND circuit
72 : disconnection detection circuit
89 : airflow sensor
90 : intake air temperature sensor
91 : disconnection detector
92 : correction circuit | In an existing disconnection detection circuit for a bridge circuit, consideration is not taken into the fact that an offset voltage or temperature characteristic of a bridge output is degraded. Provided is a disconnection detection circuit for a bridge circuit capable of suppressing a change in a characteristic of a sensor to a minimal extent. A disconnection detection circuit 8 a for a bridge circuit in accordance with the present invention comprises conducting means 9 and 10 each of which causes a current to flow from an output terminal of the bridge circuit to a predetermined potential, potential difference detecting means 12 and 13 each of which detects a potential difference between the potential at the output terminal of the bridge circuit and the predetermined potential, and a disconnection detecting means 14 that detects a disconnection on the basis of the outputs of the potential difference detecting means. | Identify and summarize the most critical technical features from the given patent document. | [
"TECHNICAL FIELD [0001] The present invention relates to a disconnection detection circuit for a bridge circuit, or more particularly, to a disconnection detection circuit for a bridge circuit that little affects an output voltage of a bridge circuit.",
"BACKGROUND ART [0002] Existing examples of a disconnection detection circuit for a bridge circuit include a sensor bridge circuit described in Japanese Unexamined Patent Application Publication No. Hei6-249730.",
"CITATION LIST Patent Literature [0003] Patent literature 1: Japanese Unexamined Patent Application Publication No. Hei6-249730 SUMMARY OF INVENTION Technical Problem [0004] An existing technology described in Japanese Unexamined Patent Application Publication No. Hei6-249730 is such that: as shown in FIG. 2 , resistors 19 and 20 are connected to outputs of a bridge circuit composed of sensor element resistors 15 , 16 , 17 , and 18 , and to a power supply and a ground respectively;",
"when the output of the bridge circuit is disconnected, an output voltage of the bridge circuit is largely varied;",
"and a sensor output obtained by amplifying the output voltage of the bridge circuit using an amplifier 21 is largely varied so that the fact that the bridge circuit has been disconnected can be detected.",
"[0005] However, in the foregoing disconnection detection circuit, consideration is not taken into the fact that since the resistors 19 and 20 are asymmetrically connected in parallel with the sensor bridge, an offset voltage or temperature characteristic of the sensor is degraded.",
"[0006] The present invention addresses the foregoing situation.",
"An object of the present invention is to provide a disconnection detection circuit for a bridge circuit which suppresses a change in a characteristic of a sensor to a minimalextent.",
"Solution to Problem [0007] In order to solve the aforesaid problem, a current is caused to flow from an output terminal of a bridge circuit to a predetermined potential, a potential difference between the potential at the output terminal of the bridge circuit and the predetermined potential is detected, and a disconnection is detected based on the potential difference.",
"Advantageous Effects of Invention [0008] According to the present invention, an adverse effect which a disconnection detection circuit imposes on an output voltage of a sensor bridge circuit can be reduced.",
"Therefore, an offset voltage or temperature characteristic of a sensor bridge output can be improved, and the disconnection of the sensor bridge can be highly precisely detected.",
"Eventually, a highly precise and highly reliable sensor can be provided.",
"BRIEF DESCRIPTION OF DRAWINGS [0009] FIG. 1 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a first embodiment;",
"[0010] FIG. 2 is a diagram showing a disconnection detection circuit for a bridge circuit of an existing technology;",
"[0011] FIG. 3 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a second embodiment;",
"[0012] FIG. 4 is a diagram showing a drain current characteristic of transistors 24 and 25 ;",
"[0013] FIG. 5 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a third embodiment;",
"[0014] FIG. 6 is a timing chart of control signals for switches 26 , 28 , 29 , 30 , 31 , and 32 ;",
"[0015] FIG. 7 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a fourth embodiment;",
"[0016] FIG. 8 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a fifth embodiment;",
"[0017] FIG. 9 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a sixth embodiment;",
"[0018] FIG. 10 is a circuit diagram of a disconnection detection circuit for a bridge circuit of a seventh embodiment;",
"[0019] FIG. 11 is a configuration diagram of a system of an eighth embodiment including a disconnection detecting means;",
"[0020] FIG. 12 is a configuration diagram of a system of a ninth embodiment including a disconnection detecting means;",
"and [0021] FIG. 13 is a configuration diagram of a system of a tenth embodiment including a disconnection detecting means.",
"DESCRIPTION OF EMBODIMENTS [0022] Now, referring to FIG. 1 to FIG. 13 , embodiments of the present invention will be described below.",
"[0023] To begin with, a disconnection detection circuit for a bridge circuit that is a first embodiment of the present invention will be described in conjunction with FIG. 1 .",
"FIG. 1 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the first embodiment.",
"[0024] A detection element 1 is formed with a bridge circuit having a series circuit composed of sensor element resistors 2 and 4 and series resistors, which include sensor element resistors 3 and 5 , connected in parallel with each other.",
"When the resistance values of the sensor element resistors 2 , 3 , 4 , and 5 vary depending on a measurement physical quantity, an intermediate voltage between the sensor element resistors 2 and 4 and an intermediate voltage between the sensor element resistors 3 and 5 vary.",
"Incidentally, the intermediate voltage between the sensor element resistors 3 and 5 is inputted to an output terminal A, and fetched into outside of the detection element 1 through the output terminal A. The intermediate voltage between the sensor element resistors 2 and 4 is inputted to an output terminal B, and fetched into outside of the detection element 1 through the output terminal B. An output voltage (a voltage between the output terminals A and B) of the bridge circuit fetched through the output terminal A and output terminal B is amplified by an amplifier 6 , and outputted to outside as a sensor output via a switching circuit 7 .",
"For the sensor element resistors, for example, platinum (Pt), tantalum (Ta), molybdenum (Mo), or silicon (Si) is selected.",
"[0025] A disconnection detection circuit 8 a includes a resistor 10 that causes a current to flow into the output terminal A, a resistor 9 that causes a current to flow into the output terminal B, a reference voltage source 11 that regenerates a reference voltage, a comparator 12 that compares the voltage at the output terminal A with the voltage at the reference voltage source 11 so as to detect the disconnection of the output terminal A, a comparator 13 that compares the voltage at the output terminal B with the voltage at the reference voltage source 11 so as to detect the disconnection of the output terminal B, and an OR circuit 14 that obtains an OR of the comparator 12 and comparator 13 .",
"If the disconnection detection circuit 8 a detects a disconnection, the switching circuit 7 fixes the sensor output to a ground voltage or a supply voltage.",
"[0026] Next, actions of the disconnection detection circuit 8 a will be described.",
"The disconnection detection circuit 8 a detects the disconnections of the output terminal A and output terminal B. [0027] If the output terminal A is disconnected, the potential at the output terminal A is brought to a ground potential by the resistor 10 .",
"The potential at the output terminal A is compared with the voltage at the reference voltage source 11 by the comparator 12 .",
"When the output terminal A is disconnected, the disconnection is reflected on the output of the comparator 12 .",
"[0028] If the output terminal B is disconnected, the potential at the output terminal B is brought to the ground potential by the resistor 9 .",
"The potential at the output terminal B is compared with the voltage at the reference voltage source 11 by the comparator 13 .",
"When the output terminal B is disconnected, the disconnection is reflected on the output of the comparator 13 .",
"[0029] Therefore, if the output terminal A or output terminal B is disconnected, the disconnection is reflected on the output of the OR circuit that obtains the OR of the outputs of the comparators 12 and 13 .",
"Owing to the constitution, the disconnection detection circuit 8 can detect the disconnections of the output terminal A and output terminal B. [0030] Next, the features of the disconnection detection circuit 8 a of the present embodiment will be described below.",
"The disconnection detection circuit 8 a is a circuit that is symmetrical with respect to the output terminals A and B of the bridge circuit of the detection element 1 , whereby an adverse effect on an output voltage of the bridge circuit of the detection element 1 can be minimized.",
"Specifically, a circuit to be connected to the output terminal A includes the resistor 10 and comparator 12 , and a circuit to be connected to the output terminal B includes the resistor 9 and comparator 13 .",
"Thus, since the identical circuits are connected to the respective output terminals, adverse effects which the disconnection detection circuit 8 a imposes on the output terminal A and output terminal B respectively are identical to each other.",
"Accordingly, an adverse effect on the output voltage of the bridge circuit of the detection element 1 (a difference voltage between the output terminal A and output terminal B) can be reduced.",
"[0031] Next, a disconnection detection circuit for a bridge circuit that is a second embodiment of the present invention will be described in conjunction with FIG. 3 and FIG. 4 .",
"Incidentally, FIG. 3 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the second embodiment, and FIG. 4 is a diagram showing a drain current characteristic of transistors 24 and 25 .",
"The disconnection detection circuit for a bridge circuit of the second embodiment is such that the resistors 9 and 10 of the disconnection detection circuit for a bridge circuit of the first embodiment are changed into a current mirror circuit composed of transistors 23 , 24 , and 25 .",
"[0032] In the disconnection detection circuit 8 b for a bridge circuit of the present embodiment, the resistors 9 and 10 are changed into a current mirror circuit composed of the transistors 23 , 24 , and 25 .",
"A constant current source 22 is connected to the transistor 23 , so that the drain currents of the transistors 24 and 25 exhibit a characteristic shown in FIG. 4 .",
"Accordingly, when the output terminals A and B are not disconnected, the impedances of the transistors 24 and 25 with respect to the output terminals A and B can be raised.",
"Therefore, an adverse effect on the output voltage of the bridge circuit can be further reduced.",
"[0033] When the disconnection of the output terminal A or output terminal B is detected, the impedance of the transistor 24 or 25 with respect to the output terminal A or B can be diminished.",
"Therefore, since the voltage at the disconnected output terminal A or B can be dropped, a margin of a threshold for the comparator 12 or 13 can be increased.",
"Eventually, precision in disconnection detection can be improved.",
"[0034] Next, a disconnection detection circuit for a bridge circuit of a third embodiment of the present invention will be described in conjunction with FIG. 5 and FIG. 6 .",
"FIG. 5 is a circuit diagram of the disconnection detection circuit for abridge circuit of the third embodiment, and FIG. 6 is a timing chart of control signals for switches 26 , 28 , 29 , 30 , 31 , and 32 .",
"The third embodiment is such that the switches 26 , 28 , 29 , 30 , 31 , and 32 and capacitors 27 , 33 , and 34 are added to the first embodiment.",
"[0035] In the present embodiment, the switches 26 , 28 , 29 , 30 , 31 , and 32 and capacitors 27 , 33 , and 34 are added so that detection of a bridge voltage and disconnection detection can be executed in time-sharing manner.",
"Specifically, at timing P 1 , the switches 26 and 30 are made in order to connect the output terminals A and B to the amplifier 6 , whereby the output voltage of the bridge circuit is detected.",
"At this time, the switches 28 and 29 enter a broken state.",
"Therefore, the disconnection detection circuit 8 c does not affect the output voltage of the bridge circuit because the bridge circuit is completely disconnected from the disconnection detection circuit 8 c .",
"The capacitor 27 is included to hold the voltage at the timing P 1 in preparation for the timing P 2 when the switches 26 and 30 are broken.",
"[0036] Thereafter, the switches 28 , 29 , 31 , and 32 are made at the timing P 2 in order to connect the output terminals A and B to the disconnection detection circuit 8 c , whereby the disconnection of the output terminal A or B of the bridge circuit is detected.",
"At this time, the switches 26 and 30 are left broken and completely disconnected from the amplifier 6 .",
"Therefore, an input resistance of the amplifier 6 does not affect the disconnection detection circuit 8 .",
"The capacitors 33 and 34 are included to hold the voltages attained at the timing P 2 in preparation for the timing P 1 when the switches 28 , 29 , 31 , and 32 are broken.",
"[0037] Next, a disconnection detection circuit for a bridge circuit that is a fourth embodiment of the present invention will be described in conjunction with FIG. 7 .",
"FIG. 7 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the fourth embodiment.",
"[0038] To begin with, a detection element 35 is a half bridge circuit composed of sensor element resistors 36 and 37 .",
"When the sensor element resistors 36 and 37 vary depending on a measurement physical quantity, a voltage at an output terminal of the bridge circuit is varied.",
"An output voltage of the half bridge circuit is amplified by an amplifier 39 and outputted to outside as a sensor output.",
"A supply voltage Vcc is connected to a power terminal of the bridge circuit, and a predetermined voltage is fed to a ground terminal via a reference voltage source 38 .",
"A disconnection detection circuit 41 includes a constant current source 42 that feeds a current to the output terminal of the half bridge circuit, a reference voltage source 43 that generates a reference voltage, and a comparator 44 that compares a voltage at the output terminal of the half bridge circuit with the value of the reference voltage source 43 so as to detect the disconnection of the output terminal.",
"If the disconnection detection circuit 41 detects a disconnection, a switching circuit 40 fixes the sensor output to a ground voltage or supply voltage.",
"[0039] Next, actions of the disconnection detection circuit will be described below.",
"The disconnection detection circuit detects the disconnection of the output terminal of the half bridge circuit.",
"To begin with, if the output terminal is disconnected, the potential at the output terminal is brought to a ground potential by the constant current source 42 .",
"The potential at the output terminal is compared with the voltage of the reference voltage source 43 by the comparator 44 .",
"Therefore, if the output terminal is disconnected, the disconnection is reflected on the output of the comparator 44 .",
"Thus, the disconnection detection circuit 41 detects the disconnection of the output terminal.",
"[0040] Next, the features of the disconnection detection circuit will be described below.",
"Assuming that the sensor element resistor 36 is a component whose resistance varies, like a thermistor, by several digits depending on temperature, the voltage at the output terminal changes from near the voltage at the power terminal of the detection element 35 to near the voltage at the ground terminal.",
"[0041] Assuming that the voltage at the ground voltage is 0 V, when the disconnection of the output terminal has to be reliably detected, it is necessary to increase the current of the constant current source 42 and to set the voltage of the reference voltage source 43 to almost 0 V. This is because, since the output of the detection element 35 at a normal time changes from near the voltage at the power terminal of the detection element 35 to near the voltage at the ground terminal, it is necessary to bring the voltage at a disconnection time to a voltage that falls outside the output at the normal time, and to bring the voltage of the reference voltage source 43 , which is a voltage to be compared by the comparator 44 , to the voltage that falls outside the output at the normal time.",
"Therefore, in order to reliably bring the voltage at the disconnection time to the voltage that falls outside the output at the normal time, that is, in order to bring the voltage to almost 0 V, it is necessary to increase the current of the constant current source 42 and to bring a comparison voltage of the comparator 44 to near almost 0 V. However, when the current of the constant current source 42 is increased, an adverse effect on a sensor output is intensified.",
"When the voltage of the reference voltage source is brought to almost 0 V, a margin of a threshold for the comparator 44 nearly runs out.",
"Eventually, precision in disconnection detection is degraded.",
"[0042] In the present embodiment, as a voltage at a ground terminal of the detection element 35 , a voltage of several volts is applied using the reference voltage source 38 .",
"In this case, even if the sensor element resistor 36 is a component whose resistance varies, like a thermistor, by several digits depending on temperature, the voltage at the output terminal changes merely from a voltage at a power terminal of the detection element 35 to the voltage of the reference voltage source 38 that is the voltage at the ground terminal.",
"Therefore, the current of the constant current source 42 can be diminished because it should merely be equal to or lower than the voltage of the reference voltage source 38 at the disconnection time of the output terminal of the detection element 35 .",
"In addition, since the voltage of the reference voltage source 43 that is a reference value for disconnection detection can be set to the voltage of the reference voltage source 38 , the margin of the threshold for the comparator 44 can be increased.",
"Eventually, precision in disconnection detection can be improved.",
"[0043] Next, a disconnection detection circuit for a bridge circuit which is a fifth embodiment of the present invention will be described in conjunction with FIG. 8 .",
"FIG. 8 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the fifth embodiment.",
"Incidentally, the disconnection detection circuit for a bridge circuit of the fifth embodiment is, contrary to the disconnection detection circuit for a bridge circuit of the fourth embodiment, such that a voltage at a power terminal of a detection element 35 is dropped by several volts using a reference voltage source 45 .",
"[0044] To begin with, the detection element 35 is a half bridge circuit composed of sensor element resistors 36 and 37 .",
"The sensor element resistors 36 and 37 vary depending on a measurement physical quantity, whereby a voltage at an output terminal of the bridge circuit is varied.",
"The output voltage of the bridge circuit is amplified by an amplifier 39 and outputted to outside as a sensor output.",
"A power terminal of the bridge circuit is connected to a supply voltage Vcc via a reference voltage source 45 .",
"A voltage that is lower than the supply voltage Vcc by the voltage of the reference voltage source 45 is fed to the power terminal.",
"A ground terminal is provided with a ground potential.",
"A disconnection detection circuit 46 includes a constant current source 47 that feeds a current into the output terminal, a reference voltage source 48 that generates a reference voltage, and a comparator 49 that compares the voltage at the output terminal with the value of the reference voltage source 48 so as to detect the disconnection of the output terminal.",
"If the disconnection detection circuit 46 detects a disconnection, a switching circuit 40 fixes the sensor output to a ground voltage or supply voltage.",
"[0045] Next, actions of the disconnection detection circuit will be described below.",
"The disconnection detection circuit detects the disconnection of the output terminal.",
"If the output terminal is disconnected, the potential at the output terminal is brought to the supply voltage by the constant current source 47 .",
"The potential at the output terminal is compared with the voltage of the reference voltage source 48 by the comparator 49 .",
"Therefore, if the output terminal is disconnected, the disconnection is reflected on the output of the comparator 49 .",
"Accordingly, the disconnection detection circuit 46 detects the disconnection of the output terminal.",
"[0046] Next, the features of the disconnection detection circuit will be described below.",
"When the sensor element resistor 36 is, like a thermistor, a component whose resistance value varies by several digits depending on temperature, the voltage at the output terminal changes from the voltage at the power terminal of the detection element 35 to the voltage at the ground terminal.",
"Assume that the voltage at the power terminal is equal to the supply voltage Vcc.",
"In this case, for reliably detecting the disconnection of the output terminal, it is necessary to increase the current of the constant current source 47 and to set the voltage of the reference voltage source 48 to almost the supply voltage Vcc.",
"However, when the current of the constant current source 47 is increased, an adverse effect on the sensor output is intensified.",
"When the voltage of the reference voltage source 48 is set to almost the supply voltage Vcc, a margin of a threshold for the comparator 49 nearly runs out.",
"Therefore, precision in disconnection detection is degraded.",
"[0047] In the present embodiment, the reference voltage source 45 is used to drop the voltage at the power terminal of the detection element 35 so that the voltage becomes lower than the supply voltage Vcc by several volts.",
"In this case, even if the sensor element resistor 36 is, like a thermistor, a component whose resistance value varies by several digits depending on temperature, the voltage at the output terminal merely changes from a voltage, which is lower by several volts than the supply voltage that is equal to the voltage at the power terminal of the detection element 35 , to the ground voltage.",
"Therefore, the current of the constant current source 47 can be diminished because when the output terminal of the detection element 35 is disconnected, the voltage at the power supply should merely approach the supply voltage with a margin equivalent to the voltage of the reference voltage source 45 .",
"In addition, the voltage of the reference voltage source 48 that is a reference value for disconnection detection can be set with a margin equivalent to the voltage of the reference voltage source 45 .",
"Therefore, the margin of the threshold for the comparator 49 can be increased.",
"Eventually, precision in disconnection detection can be improved.",
"[0048] Next, a disconnection detection circuit for a bridge circuit that is a sixth embodiment of the present invention will be described below in conjunction with FIG. 9 .",
"FIG. 9 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the sixth embodiment.",
"[0049] To begin with, a detection element 50 is a bridge circuit composed of sensor element resistors 51 , 52 , 53 , and 54 .",
"The sensor element resistors 51 , 52 , 53 , and 54 vary depending on a measurement physical quantity, whereby voltages at output terminals A and B of the bridge circuit are varied.",
"An output voltage of the bridge circuit (a voltage between the output terminals A and B) is analog-to-digital converted by a delta-sigma modulator 55 (hereinafter, a ΔΣ modulator), and outputted to outside as a sensor output.",
"Incidentally, the ΔΣ modulator 55 includes an SC integrator that is composed of switches 56 , 58 , 63 , and 65 which act at the timing P 1 shown in FIG. 6 , switches 59 , 60 , 61 , and 62 which act at the timing P 2 shown in FIG. 6 , capacitors 57 , 64 , 66 , and 68 , and an amplifier 67 , a comparator 69 that compares the output of the SC integrator, a local digital-to-analog (D/A) converter 70 that outputs a voltage according to the output of the comparator 69 .",
"A disconnection detection circuit 72 includes a switch 74 that acts at the timing P 2 shown in FIG. 6 so as to link the output terminal A and a constant current source 76 , a switch 73 that acts at the timing P 2 shown in FIG. 6 so as to link the output terminal B and a constant current source 75 , the constant current source 76 that feeds a current into the output terminal A, the constant current source 75 that feeds a current into the output terminal B, a sample-and-hold circuit that samples voltages across the constant current sources 75 and 76 at the timing P 2 shown in FIG. 6 and is composed of switches 77 and 78 and capacitors 79 and 80 , a reference voltage source 81 that generates a reference voltage, a comparator 82 that compares a voltage across the capacitor 79 with the value of the reference voltage source 82 so as to detect the disconnection of the output terminal A, a comparator 83 that compares a voltage across the capacitor 80 with the value of the reference voltage source 81 so as to detect the disconnection of the output terminal B, and an OR circuit 84 that obtains an OR of the comparator 82 and comparator 83 .",
"In addition, there is an AND circuit 71 that, if the disconnection detection circuit 72 detects a disconnection, fixes the output of the ΔΣ modulator 55 to a ground.",
"[0050] Next, actions of the present embodiment will be described below.",
"The ΔΣ modulator 55 discharges the capacitors 57 and 64 at the timing P 2 .",
"At the timing P 1 , the ΔΣ modulator 55 samples the output voltage of the bridge circuit and charges the capacitors using the SC integrator.",
"The disconnection detection circuit 72 acts at the timing P 2 , which is a non-sampling period of the ΔΣ modulator 55 , so as not to affect the action of the ΔΣ modulator 55 .",
"The disconnection detection circuit 72 turns on the switches 73 , 74 , 77 , and 78 at the timing P 2 so that a constant current flows into the output terminals A and B of the bridge circuit.",
"At this time, if the output terminal A or output terminal B is disconnected, the voltage across the associated constant current source 75 or 76 is dropped to almost a ground potential.",
"The voltage is held by the sample-and-hold circuit including the switches 77 and 78 and capacitors 79 and 80 , and compared by the comparator 82 or 83 , whereby the disconnection of the output terminal A or B is detected.",
"[0051] Next, the features of the present embodiment will be described below.",
"Since the disconnection detection circuit 72 is a circuit symmetrical with respect to the output terminals A and B of the bridge circuit of the detection element 50 , an adverse effect on the output voltage of the bridge circuit of the detection element 50 can be minimized.",
"[0052] Since the disconnection detection circuit 72 acts during the non-sampling period of the ΔΣ modulator 55 , the action of the disconnection detection circuit 72 does not affect the ΔΣ modulator 55 .",
"In reverse, the action of the ΔΣ modulator 55 does not affect the disconnection detection circuit 72 .",
"[0053] When the ΔΣ modulator 55 is employed in a detection circuit for an output voltage of a bridge circuit, it is very easy to fix an output signal to a value that cannot be outputted as an ordinary sensor output because an AND circuit alone is needed.",
"[0054] Next, a disconnection detection circuit for a bridge circuit that is a seventh embodiment of the present invention will be described in conjunction with FIG. 10 .",
"FIG. 10 is a circuit diagram of the disconnection detection circuit for a bridge circuit of the seventh embodiment.",
"The present embodiment is such that the constant current sources 75 and 76 of the sixth embodiment are replaced with a switched capacitor circuit composed of switches 85 and 87 and capacitors 86 and 88 .",
"[0055] In the present embodiment, faster detection than that achieved using the constant current sources 75 and 76 is enabled by replacing the constant current sources 75 and 76 with a switched capacitor circuit.",
"This is because the switched capacitor circuit provides less impedance than the constant current sources do.",
"This makes it possible to speed up an operating clock for the ΔΣ modulator 55 .",
"Eventually, precision of the ΔΣ modulator 55 and responsiveness thereof can be improved.",
"[0056] Next, a system that is an eighth embodiment of the present invention and includes a disconnection detecting means will be described in conjunction with FIG. 11 .",
"FIG. 11 is a configuration diagram of the system of the eighth embodiment including the disconnection detecting means.",
"[0057] The present embodiment includes an airflow sensor 89 that detects an air flow rate Q, an intake air temperature sensor 90 that detects intake air temperature Ta, a disconnection detector 91 that detects the disconnection of the intake air temperature sensor 90 , a correction circuit 92 that corrects the air flow rate Q, which is an output signal of the airflow sensor 89 , with the intake air temperature Ta that is an output signal of the intake air temperature sensor 90 , and a switching circuit 93 that, if the disconnection detector 91 detects a disconnection, fixes the signal of the intake air temperature Ta, which is handed to the correction circuit 92 , to 25° C. [0058] The present embodiment is the system in which if the intake air temperature sensor 90 is disconnected and outputs the signal having an extremely large error, the correction circuit 92 is prevented from performing excess correction processing and outputting a signal, which has an extremely large error, as a sensor output (air flow rate signal).",
"In the present embodiment, if the intake air temperature sensor 90 is disconnected, the switching circuit 93 fixes the signal of the intake air temperature Ta, which is fed to the correction circuit 92 , to 25° C. Thus, excessive correction is prevented.",
"Accordingly, even if the intake air temperature sensor 90 is disconnected, an error in the sensor output can be suppressed.",
"In particular, as far as an airflow sensor that measures an intake air flow rate of an automobile is concerned, if an error caused by the airflow sensor is large, a fatal phenomenon that an engine is not started takes place.",
"In particular, such an event must be avoided that although the airflow sensor 89 does not fail, the sensor output becomes extremely abnormal because of the failure of the intake air temperature sensor 90 .",
"The present system can avoid the event.",
"[0059] Next, a system that is a ninth embodiment of the present invention and includes a disconnection detecting means will be described in conjunction with FIG. 12 .",
"FIG. 12 is a configuration diagram of the system of the ninth embodiment including the disconnection detecting means.",
"The present embodiment is a system that includes the disconnection detecting means and has the switching circuit 93 , which is included in the system of the eighth embodiment including the disconnection detecting means, changed into a switching circuit 94 .",
"[0060] In the present embodiment, the switching circuit 93 is changed into the switching circuit 94 .",
"If the intake air temperature sensor is disconnected, the correction circuit 92 is bypassed in order to prevent excessive correction.",
"Thus, even if the intake air temperature sensor 90 is disconnected, an error in the sensor output can be suppressed.",
"[0061] Next, a system that is a tenth embodiment of the present invention and includes a disconnection detecting means will be described in conjunction with FIG. 13 .",
"FIG. 13 is a configuration diagram of the system of the tenth embodiment including the disconnection detecting means.",
"The present embodiment is a system that includes the disconnection detecting means, has a circuit temperature sensor 95 added to the system of the eighth embodiment including the disconnection detecting means, and has a switching destination at a disconnection time by the switching circuit 93 changed to another.",
"[0062] In the present embodiment, the circuit temperature sensor 95 is added, and the switching destination at a disconnection time by the switching circuit 93 is changed to another.",
"If the intake air temperature sensor is disconnected, the switching destination of the correction circuit 92 is set to the circuit temperature sensor 95 in order to prevent excessive correction.",
"This is attributable to the fact that in a steady state, there is no large difference between the intake air temperature Ta and circuit temperature Tlsi.",
"Accordingly, even if the intake air temperature sensor 90 is disconnected, an error in the sensor output can be suppressed.",
"LIST OF REFERENCE SIGNS [0000] 1 , 35 , 50 : detection element 2 , 3 , 4 , 5 , 15 , 16 , 17 , 18 , 36 , 37 , 51 , 52 , 53 , 54 : sensor element resistor 6 , 21 , 39 , 67 : amplifier 7 , 40 , 93 , 94 : switching circuit 8 , 8 a , 8 b , 8 c , 41 , 46 : disconnection detection circuit 9 , 10 , 19 , 20 : resistor 11 , 38 , 43 , 45 , 58 , 81 : reference voltage source 12 , 13 , 44 , 49 , 69 , 82 , 83 : comparator 14 , 84 : OR circuit 22 , 42 , 47 , 75 , 76 : constant current source 23 , 24 , 25 : transistor 26 , 28 , 29 , 30 , 31 , 32 , 56 , 58 , 59 , 60 , 61 , 62 , 63 , 65 , 73 , 74 , 77 , 78 , 85 , 87 : switch 27 , 33 , 34 , 57 , 64 , 66 , 68 , 79 , 80 , 86 , 88 : capacitor 55 : ΔΣ modulator 70 : local D/A converter 71 : AND circuit 72 : disconnection detection circuit 89 : airflow sensor 90 : intake air temperature sensor 91 : disconnection detector 92 : correction circuit"
] |
BACKGROUND OF THE INVENTION
There is a great need in the food industry for a sweet, zero calorie, non-toxic sugar. An ideal example would be a nonmetabolizable fructose. D-Fructose, the sweetest natural sugar, provides excellent organoleptic acceptance and mouth feel. The United States uses over 23 billion pounds of sucrose per year and some of it is hydrolyzed to its constituent sugars namely one unit of D-glucose and one unit of D-fructose. The mixture is commercially called invert sugar. Since D-fructose is 1.7 times as sweet as sucrose, and D-glucose 0.7 times as sweet as sucrose, the total sweetness of invert sugar is higher than that of sucrose. With the advent of enzyme engineering, it has become possible to convert D-glucose to an equilibrium mixture of D-glucose and D-fructose in a proportion of 54% to 46% respectively, and hence, produce the sweetness of invert sugar from low cost D-glucose, a product of the corn wet milling industry. As a consequence, the use of fructose in the food industry has increased extensively.
With all of the desirable advances in producing the sweet sugar D-fructose, there has been no reduction in caloric value except for the lesser amount of D-fructose required to give the same sweetness as sucrose. Both D-glucose and D-fructose are completely and equally metabolized in humans to produce equivalent caloric energy.
With the health need to take in less calories, some of the normal metabolic sugars should be replaced with other acceptable nonmetabolizable and non-toxic sweeteners. This has been done with the development of synthetic sweeteners such as saccharin and aspartame. However, a much more desirable sweetener is L-fructose which has the same sweetness as natural D-fructose. It has no toxicity and seems not to be metabolized by humans, thus yielding no caloric value. L-Fructose is the mirror image of D-fructose. It has the same taste and most of the other properties of D-fructose but is not a substrate for the metabolic enzymes of the human system.
Examples of sweetened substrates which may be prepared with L-fructose can be found in U.S. Pat. No. 4,262,032 to Levin which is expressly incorporated herein. This patent describes and claims the use of L-fructose and other L-hexose monosaccharides as sweetening agents.
L-Fructose, which has not been found in nature, was synthesized for the first time by Fischer. See E. Fischer, Ber., 23 (1890) 370-394. DL-Glucose phenylosazone was prepared from α-acrose and hydrolyzed to the glycosulose, which was reduced to DL-fructose. L-Fructose was isolated from the mixture. L-Fructose was later synthesized by Wolfrom and Thompson from L-arabinonic acid in five steps. See M. L. Wolfrom and A. Thompson, Methods of Carbohydr. Chem., 1 (1962) 118-120.
Recently, L-fructose was prepared by aldol condensation. See S. Morgenlie, Carbohydr. Res., 107 (1982) 137-141. DL-Glyceraldehyde condensed with 1,3-dihydroxy-2-propanone catalyzed by Dowex 1 (OH - ) resin to give a hexulose mixture. Crystallization of the mixture from methanol yielded 54% of DL-fructose. Treatment of the DL-fructose mixture with baker's yeast gave a product from which 62% of 2,3:4,5-di-O-isopropylidene-β-L-fructopyranose was isolated after acetonation. When L-glyceraldehyde was used as starting material, 2,3:4,5-di-O-isopropylidene-β-L-fructopyranose was isolated in 60-65% yield after acetonation of the hexulose mixture.
L-Fructose has been prepared enzymatically from L-mannose by an isomerase present in cell-free extracts of Aerobacter aerogenes grown on L-mannose to give L-fructose in 28-32% yield. See J. W. Mayo and R. J. Anderson, Carbohydr. Res., 8 (1968) 344-347.
Both chemical and enzymic procedures either are too elaborate or require relatively expensive starting material. To commercialize L-fructose as a sweetener requires a low cost process. A simple method for the synthesis of L-fructose which starts with L-sorbose, a relatively inexpensive industrial chemical would be desirable. The only structural difference between L-sorbose and L-fructose is the reverse configuration of the hydroxyl groups at C-3 and C-4.
SUMMARY OF THE INVENTION
It has now been discovered that L-fructose can be produced in high yield from L-sorbose. The process is simple and convenient to conduct. The process involves the inversion of the hydroxyl groups on carbon atoms C3 and C4 of L-sorbose to produce L-fructose. This inversion can be accomplished in simple, commercial equipment with the aid of common reagents.
In accordance with the present invention, L-sorbose or an appropriately blocked derivative thereof is reacted so as to introduce a good leaving group, preferably mesyl or tosyl, at chiral carbon C3 thereby replacing the proton of the hydroxyl previously at that position. The leaving group is then displaced, preferably under alkaline conditions, in such a way that the hydroxyl oxygen atom at chiral carbon C4 attaches to chiral carbon C3, thereby displacing the leaving group while forming a 3,4-oxirane (epoxide) ring. The 3,4-oxirane ring forms in a downward position relative to the Haworth representation in which the ring oxygen atom is to the right and behind the plane of the paper thereby inverting chiral carbon C3 during formation of the 3,4-oxirane ring.
The 3,4-oxirane ring is then opened under acidic or alkaline conditions to yield a sugar ring with a hydroxyl group in a position above the sugar ring at chiral carbon C4, and a hydroxyl group in a downward position at C3.
Removal of any remaining blocking groups yields L-fructose. This may be accomplished, for example, by acid hydrolysis.
Also, in accordance with the above-described process, two novel classes of compounds are disclosed which act as intermediaries in the synthesis of L-fructose. These are a 3,4-anhydro-L-sorbose having the formula: ##STR1## wherein R 1 represents a good leaving group, R 2 represents a (lower)alkyl group, or R 1 and R 2 both are attached to a good leaving group and an L-sorbofuranose derivative selected from those having the formulas ##STR2## wherein R 1 represents a good leaving group, R 2 and R 3 represent hydrogen or together are attached to a good leaving group, R 4 represents a (lower)alkyl group, R 5 represents a good leaving group, or R 4 and R 5 taken together represent a (lower)divalent hydrocarbon group.
DETAILED DESCRIPTION OF THE INVENTION
There are several modifications of L-sorbose that can serve as starting materials for the conversion. Each is easily made and serves well in the conversion process. Each can be made by any of several well known processes.
Among such convenient starting materials are methyl L-sorbofuranoside, 1,2-O-isopropylidene-L-sorbofuranose, 1,2-O-isopropylidene-L-sorbopyranose, 2,3-O-isopropylidene-L-sorbofuranose, 2,3-O-isopropylidene-L-sorbopyranose, 1,3-O-isopropylidene-L-sorbofuranose, 1,3-O-isopropylidene-L-sorbopyranose, 1,2:4,6-di-O-isopropylidene-L-sorbofuranose, 2,3:4,6-di-O-isopropylidene-L-sorbofuranose, 1,3:4,6-di-O-isopropylidene-L-sorbofuranose, methyl 4,6-O-isopropylidene-L-sorbofuranoside, ethyl 4,6-O-isopropylidene-L-sorbofuranoside, methyl 1,3:4,6-di-O-isopropylidene-L-sorbofuranoside, and ethyl 1,3:4,6-di-O-isopropylidene-L-sorbofuranoside. Other appropriately blocked starting materials, such as appropriately blocked L-sorbofuranosides, will be apparent to those knowledgeable in carbohydrate chemistry.
The isopropylidene blocking group can be prepared in many ways using a variety of reagents, such as acetone and 2,2-dimethoxypropane. The isopropylidene blocking group can be replaced by other blocking groups, such as benzylidene, ethylidene, sec. butylidene and cyclohexylidene.
Each of the starting materials can be derivatized at position C3 with a good leaving group such a tosyl, mesyl or other, such that on treatment under alkaline condition, as for example with sodium hydroxide or sodium methoxide, the leaving group can be displaced by the oxygen atom of the hydroxyl group at C4 to produce a three membered 3,4-oxirane ring wherein the 3,4-oxirane ring is below the sugar ring as it is in Haworth representation with the epoxide oxygen bonds being on the right side of the sugar if it were written upright in a normal Fischer projection. The formation of this particularly designed 3,4-oxirane ring rather than one of another steric arrangement is a prime discovery of this invention, for not only is the ring in correct position for the next conversion step, it is obtained in nearly 100% yield.
The next and last conversion step is to hydrolytically open the 3,4-oxirane ring with either acid or base to produce L-fructose or an L-fructose derivative which on acid treatment will yield L-fructose. Another discovery of merit, in the conversion, is the finding that the 3,4-oxirane ring opens specifically in the correct direction maintaining chiral configuration at carbon C3 while inverting chirality at carbon C4.
The process for converting L-sorbose to L-fructose is especially useful because it has been discovered that it is possible to treat an appropriate derivative of L-sorbose so as to introduce in high yield a good leaving group at chiral carbon C3 and to displace this group in such a way to give nearly 100% yield of a 3,4-oxirane ring involving chiral carbon C3 and C4 with concommitant inversion of chiral carbon atom C3.
The process is also most useful because of the finding that the 3,4-oxirane produced as described above can be opened in nearly 100% yield in such a manner that the chiral carbon atom at C4 is inverted by introduction of a hydroxyl group from the top side of the ring at C4 and hence, opposite to the oxygen bond at C4 involved in the 3,4-oxirane ring formation.
Various good leaving groups can be introduced at chiral carbon C3 of an L-sorbose derivative. P-Toluenesulfonyl (tosyl) and methylsulfonyl (mesyl) are preferred with mesyl especially preferred because of its low cost and ease of recovery and recycle.
The entire process of converting L-sorbose or an appropriately blocked L-sorbose derivative to L-fructose is amazingly low cost involving introducing the appropriate leaving group at chiral carbon C3, treating with alkali and then with acid. Both the alkali treatment and acid treatment can be conducted in the same reaction vessel without isolation or purification of the intermediate 3,4-oxirane derivative.
If good leaving groups are introduced at other positions than chiral carbon atom C3, no harm occurs since they will be hydrolyzed and removed in the last acid treatment step. It is preferred that a leaving group not be attached to carbon atom C4 or to another carbon where it can adversely effect the desired 3,4-oxirane ring formation at C3 and C4.
A preferred embodiment may be illustrated by the following reaction scheme: ##STR3##
In this first preferred embodiment, L-fructose (7) is synthesized from L-sorbose (1) via a 1,2:4,6-di-O-isopropylidene-α-L-sorbofuranose (2) intermediate.
L-Sorbose can react with acetone or 2,2-dimethoxypropane to produce 2. 1,2:4,6-Di-O-isopropylidene-α-L-sorbofuranose (2), a kinetic product in the isopropylidenation of L-sorbose, is formed normally in about 5% yield. However, using tin(II) chloride as a catalyst, 2 can be obtained in greater than 80% yield as indicated by thin layer chromatography. The reaction is slow unless a small amount of 1,2-dimethoxyethane or acetone is present to improve the solubility of tin(II) chloride. 1,2-Dimethoxyethane is preferred for highest yield.
If acetone replaces 1,2-dimethoxyethane as a solvent, the yield may be somewhat lower. The yield can still be maintained high, however, by keeping the proportion of acetone in the reaction mixture as low as possible. A small amount of acetone is required as solvent for the reaction because tin(II) chloride is not soluble in 2,2-dimethoxypropane.
Compound 2 is then reacted with methanesulfonylchloride. Mesylation of 2 is complete in 1-4 hours to yield 1,2:4,6-di-O-isopropylidene-3-O-mesyl-α-L-sorbofuranose (3) in 83% yield. Compound 3 crystallizes readily from the reaction mixture upon the addition of water. Preferably, compound 3 is prepared from L-sorbose without isolation of the intermediate 2.
The 4,6-O-isopropylidene protecting group of 3 is selectively removed to yield 1,2-O-isopropylidene-3-O-mesyl-α-L-sorbofuranose (4) by addition of either a mixture of acetone and 0.25% aqueous sulfuric acid at 25° C. or 60% acetic acid at 40° C. The sulfuric acid reagent is better in terms of the cost and simplification of the process. A small amount of by-product, likely 3-O-mesyl-L-sorbose, is also detected, particularly in the 0.25% sulfuric acid medium. Compound 4 is crystallized from the reaction mixture after most of the acetone is removed.
Formation of the 3,4-anhydro ring is readily achieved in alkaline condition at 25° C. to yield 5. The alkali concentration and/or the proportion of methanol in the reaction mixture is critical. For example, when a solution of 4 in methanol (100 ml) and 1N sodium hydroxide (70 ml) is heated at 45° C. for 5 hours, only a very small amount of 4 is converted to 5.
Opening of the anhydro ring, however, is more difficult. Ring opening is completed in strong, aqueous alkaline solution by heating 3 days at 70°-80° C. A small amount of by-product is detected. On the other hand, a solution of 4 in 5% aqueous potassium hydroxide solution, refluxed for 3 hours, gives 6 as a single product.
Removal of the 1,2-O-isopropylidene group from 6 by acid hydrolysis gives 7 as the major product.
L-Fructose can be derivatized according to reported procedures to yield 8. See S. Morgenlie, Carbohydrate. Res., 107 (1982) 137-141. Compound 8 had the same m.p. and optical rotation as reported in the literature.
A second preferred embodiment for producing L-fructose from L-sorbose utilizes methyl 4,6-O-isopropylidene-1-3-di-O-tolysulfonyl-α-L-sorbofuranoside (10) as an intermediate.
This second preferred embodiment may be illustrated by the following reaction scheme. ##STR4##
Methyl 4,6-O-isopropylidene-α-L-sorbofuranoside (9) is prepared in one step following reported procedures. See T. Maeda, K. Tori, S. Satoh and K. Tokuyama, Bull. Chem. Soc. Japan, 41 (1968) 2495-2503. Compound 9 is then reacted with a solution containing p-toluenesulfonyl chloride. Tosylation of 9 is complete in two days to give 10 and a trace amount of methyl 4,6-O-isopropylidene-1-O-p-tolysulfonyl-α-L-sorbo-furanoside.
The isopropylidene group of 10 is readily removed in 60% acetic acid solution to give 11. The reaction mixture is made alkaline to form a 3,4-anhydro-ring by intramolecular nucleophilic displacement of the sulfonyloxy group. The alkali concentration and/or the proportion of methanol in the reaction mixture is critical. For example, when a solution of 11 in methanol (100 ml) and 1N sodium hydroxide (70 ml) is heated at 45° C. for 5 hours, only a very small amount of 11 is converted to 12. The conditions required for alkaline scission of three membered anhydro-rings are, in general, more drastic than the conditions used for ring closure. No anhydro-ring opening is detected under the alkaline conditions used in this latter reaction.
Under milder, acidic conditions, 12 is converted to 13. The anhydro-ring is hydrolyzed but the glycosidic bond and the sulfonyl ester linkage survive. The p-toluenesulfonyl ester linkage is relatively resistant to acid hydrolysis with the glycosidic bond stabilized by the inductive effect from the adjacent sulfonyl ester group.
Because of the difficulty in cleaving the sulfonyl ester linkage, a high concentration of sulfuric acid (10N) is employed. The anhydro-ring opens exclusively at C4. This apparently favors the development of a positive charge at C4 rather than at C3 because of the inductive effect from the substituents at C1 and C2. The major product from the acid hydrolysis is L-fructose (7). Some minor products are also detected.
Crystalline 7 shows an optical rotation of about +60° within 30 minutes after dissolution. The optical rotation raises to +88° after 48 hours at 25° C. The increase in optical rotation indicates that the crystalline material is a β-L-anomer.
L-Fructose (7), when subjected to a tasting panel for sweetness is found to be as sweet as D-fructose.
The following Examples illustrate the procedures described in the first embodiment.
1,2:4,6-Di-O-isopropylidene-3-O-mesyl-α-L-sorbofuranose (3) was prepared as follows.
EXAMPLE 1
L-Sorbose (1, 8.24 g) was suspended in 1,2-dimethoxyethane (25 ml) containing tin(II) chloride (10 mg) and 2,2-dimethoxypropane (13.4 ml) was added. The mixture was refluxed, with stirring, for 2 hours until the solution was clear. A drop of pyridine was added and the mixture was concentrated to a syrup. The syrup was dissolved in chloroform and washed with water. The chloroform fraction was dried (Na 4 SO 4 ) and evaporated to a syrup. The syrup was extracted with hot petroleum ether. Crystallization occurred from the cooled extract. Recrystallization from petroleum ether gave 2 (4.88 g, 41%), m.p. 71°-73°, [α] D 25 -24.7° (c 1.029, acetone); literature m.p. 72°-73° 8 α] D 25 -23.9. The mass spectrum showed the largest fragment ion at m/e 245 (M + -CH 3 ).
Anal. Calc. for C 12 H 20 O 6 ; C, 55.37; H, 7.75. Found: C, 54.93; H, 7.67.
To a solution of 2 (0.7 g) in pyridine (1 ml), cooled in an ice bath, was added methanesulfonyl chloride (0.31 ml). After 1 hour, ice was added and the white crystalline material was washed with water to give 3 (0.76 g, 83.5%).
EXAMPLE 2
L-Sorbose (30 g) was suspended in 2,2-dimethoxypropane (90 ml). 1,2-Dimethoxyethane (3 ml) containing tin(II) chloride (150 mg) was added. The mixture was refluxed, with stirring, for 2 hours until the solution was clear and then evaporated to a syrup. The syrup was dissolved in pyridine (60 ml) and cooled in an ice bath. Methanesulfonyl chloride (19.4 ml) was added. After storage in refrigerator for 16 hours and then at 25° C. for 4 hours, water (1000 ml) was added. The crystals produced were collected by filtration to give 3 (28.9 g, 51%). Recrystallization from ethanol gave 3 as colorless needles, m.p. 123°-124° C.
Anal. Calc. for C 13 H 22 O 8 S: C, 46.14; H, 6.56; S, 9.48. Found: C, 46.25; H, 6.70, S, 9.11.
EXAMPLE 3
L-Sorbose (10 g) was suspended in 2,2-dimethoxypropane (30 ml). 1,2-Dimethoxyethane (1 ml) containing tin(II) chloride (30 mg) was added. The mixture was refluxed, with stirring, for 2.5 hours until the solution became clear. It was then evaporated to a syrup. The syrup was dissolved in pyridine (20 ml) and cooled in an ice bath. Methanesulfonyl chloride (6.45 ml) was added slowly. After storage at room temperature for 2.5 hours, water (400 ml) was added. Crystals produced were collected by filtration to give 3 (8.63 g, 46%).
EXAMPLE 4
L-Sorbose (4.122 g) was suspended in 2,2-dimethoxypropane (13.2 ml). Acetone (1 ml) containing tin(II) chloride (15 mg) was added. The mixture was refluxed, with stirring, for 100 minutes until the solution became clear. It was then evaporated to a syrup. The syrup, dissolved in pyridine, (8.2 ml) was cooled in an ice bath. Methanesulfonyl chloride (2.66 ml) was added slowly. After storage at room temperature for 2.5 hours, water (200 ml) was added. Produced crystals were collected by filtration to give 3 (3.08 g, 40%).
L-Fructose was prepared from compound 3 as shown in the following examples.
EXAMPLE 5
Compound 3 (2.5 g) was dissolved in acetone (20 ml) and 0.25% sulfuric acid in water (15 ml) was added. After storage at room temperature for 24 hours, the solution was made alkaline with a 9N sodium hydroxide solution (2 ml). The solution was then heated at 70°-80° C. for 48 hours, acidified with 18N sulfuric acid solution (1 ml), heated at 70°-80° C. for 20 minutes and then neutralized with 2N sodium hydroxide solution (5 ml). The mixture was taken to dryness and the residue extracted with ethanol (40 ml). The ethanol solution was concentrated to give L-fructose as a syrup (0.97 g, 73%). The syrup was contaminated with a small amount of by-products with lower mobility than L-fructose on silica gel thin layer chromatography. The mixture was purified on a silica gel column (4:1:0.7, v/v/v, ethyl acetatemethanol-water) to give a syrup product (0.83 g, 62%).
EXAMPLE 6
Compound 3 (3 g) dissolved in 60% acetic acid (30 ml) was heated at 40° C. for 3 hours. The mixture was made alkaline with 10N sodium hydroxide solution (40 ml), heated at 70° C. for 15 hours and then acidified with 18N sulfuric acid solution (30 ml). The salt was filtered off and the filtrate left at room temperature for 18 hours and 70° C. for 2 hours. The mixture was neutralized with 10N sodium hydroxide solution (3.5 ml). The salt was removed by ethanol precipitation. After filtration, the filtrate was concentrated, deionized with a column of Amberlite MG-1 ion-exchange resin, and eluted with water. The effluent was concentrated to give L-fructose as a syrup (1.21 g, 76%).
EXAMPLE 7
Compound 3 (1 g) is dissolved in acetone (10 ml) and 0.24% sulfuric acid in water (10 ml) is added. After storage at room temperature for 16 hours, the solution is neutralized with solid sodium hydrogencarbonate and filtered. Acetone is removed by evaporation until crystallization occurs to give 1,2-O-isopropylidene-3-O-mesyl-α-L-sorbofuranose. The crystalline material is dissolved in 5% potassium hydroxide (30 ml) and refluxed for 2.5 hours. The mixture is acidified to pH about 2 with 25% sulfuric acid in water. After storage at room temperature for 16 hours until the reaction is complete, the mixture is neutralized with 50% potassium hydroxide in water and taken to dryness. The residue is extracted with ethanol and the ethanol solution is concentrated to give L-fructose as a syrup. The syrup is deionized with a column of Amberlite MB-1 ion exchange resin.
The following examples illustrate the procedures for preparing L-fructose from L-sorbose by means of intermediate 10.
EXAMPLE 8
L-Sorbose (1, 40 g) was refluxed in 2,2-dimethoxypropane (100 ml) containing p-toluenesulfonic acid (500 mg) for 2 hours. The mixture was neutralized with a slight excess of methanolic sodium methoxide and concentrated to a syrup. The syrup was extracted with benzene (2×50 ml) and the benzene fraction was extracted with water (3×50 ml). The aqueous fraction saturated with sodium chloride was extracted with chloroform (3×100 ml). The chloroform was evaporated and the residue chromatographed on a silica gel column, eluted with 9:1 (v/v) hexane-acetone. Compound 9 was isolated as a crystalline material (1.6 g, 3.1%); R f (thin layer chromatography on silica gel in 9:1, v/v, chloroformacetone) 0.26. Recrystallization from ether gave 2, m.p. 109°-110° C.; lit. m.p. 108°-109° C.
Anal. Calc. for C 10 H 18 O 6 : C, 51.27; H, 7.75. Found: C, 51.98; H, 7.99.
A solution of 9 (1.2 g) in pyridine (1.8 ml) was cooled in an ice bath and p-toluenesulfonyl chloride (3.3 g) in pyridine (5 ml) was added slowly. After storage at 25° C. for 2 days, ice was added and the mixture was extracted with chloroform (2×20 ml). The organic layer was washed twice with water, dried (Na 2 SO 4 ) and evaporated to a syrup. Traces of pyridine in the residue were removed by co-evaporation with toluene to give 10 as a syrup (2.9 g, 100%), which was chromatographically pure; R f (thin layer chromatography on silica gel in 9:1, v/v, chloroform-acetone) 0.80; [α] D 25 +6° (c 2.5, chloroform). The mass spectrum showed the largest fragment ion at m/e 527 (M-CH 3 ); P.m.r. (CDCl 3 ); δ7.20-7.85 (m, 8H, 2C 6 H 4 CH 3 ), 3.60-4.63 (m, 7H, H-1, - 3, -4, -5, -6), 3.17 (s, 3H, OCH 3 ), 2.43, 2.41 (s, s, 6H, 2C 6 H 4 CH 3 ) and 1.25, 1.15 (s, s, 6H, 2C(CH 3 ) 2 ).
Anal. Calc. for C 24 H 30 O 10 S 2 : C, 53.13; H, 5.57; S, 11.82. Found: C, 53.21; H, 5.51; S, 11.74.
Compound 10 (2.3 g) was stirred in 60% acetic acid solution (23 ml) at 55° C. for 2.5 hours. The pH of the solution was raised to 5-6 with 10N sodium hydroxide solution and the mixture was extracted with chloroform (2×50 ml). The chloroform was evaporated to give 11 as a syrup (2 g, 94%); R f (thin layer chromatography on silica gel in 9:1, v/v, chloroform-acetone) 0.25; [α] D 25 -46° (c
1.8, chloroform). P.m.r. (CDCl 3 ): δ7.06-7.85 (m, 8H, 2C 6 H 4 CH 3 ), 3.40-4.80 (m, 7H, H-1, -3, -4, -5, -6), 3.20 (s, 3H, OCH 3 ) and 2.40, 2.37 (s, s, 6H, 2C 6 H 4 CH 3 ).
Anal. Calc. for C 21 H 26 O 10 S 2 : C, 50.19; H, 5.22; S, 12.76. Found: C, 50.39; H, 5.48; S, 12.90.
To a solution of 11 (1.43 g) in methanol (1 ml) was added 2N sodium hydroxide solution (1 ml). After 2 hours at 40° C., 11 was converted to a single product, which showed positive in a vicinal epoxide test. Methanol (20 ml) was added and the solution was neutralized with 5N sulfuric acid solution. The salt was filtered and water (10 ml) was added. After evaporating the methanol, the aqueous solution was extracted with chloroform (2×50 ml). The chloroform was evaporated off to give 12 as a syrup (0.85 g, 90%); [α] D 25 -27° (c 2.5, chloroform). P.m.r. (CDCl 3 ); δ7.10-7.87 (m, 4H, C 6 H 4 CH 3 ), 3.50-4.30 (m, 7H, H-1, -3, -4, -5, -6), 3.17 (s, 3H, OCH 3 ) and 2.40 (s, 3H, C.sub. 6 H 4 CH 3 ).
Anal. Calc. for C 14 H 18 O 7 S: C, 50.90; H, 5.49; S, 9.17. Found: C, 50.76; H, 5.84; S, 9.47.
A solution of 12 (0.29 g) in a small amount of methanol was acidified with 1N sulfuric acid solution to pH 2-3. After storage at 25° C. for 2 days, 12 was cleanly converted to a single product. The mixture was neutralized with 1N sodium hydroxide solution and extracted with chloroform. The organic fraction was concentrated and the residue chromatographed on a silica gel column. Elution with 9:1 (v/v) chloroform-acetone gave 13 as a syrup (0.29 g, 95%). The mass spectrum showed the highest peak at m/e 317 (M--OCH 3 ). P.m.r. (CDCl 3 ): δ7.10-7.83 (m,4H, C 6 H 4 CH 3 ), 3.40-4.30 (m,7H, H-1, -3, -4, -5, -6), 3.23 (s, 3H, OCH 3 ) and 2.43 (s, 3H, C 6 H 4 CH 3 ).
To a solution of 13 (7.5 g) in ethanol (50 ml) was added 10N sulfuric acid solution (125 ml). The mixture was heated at 70° C. for 1 hour and neutralized with 10N sodium hydroxide solution. After addition of ethanol and filtering off the salts the filtrate was concentrated. The residue was chromatographed on a silica gel column. Elution with 4:1:0.7 (v/v/v) ethyl acetate-methanol-water gave 7 as a syrup (3.6 g, 88%). The syrup was de-ionized with a column of Amberlite MB-1 ion-exchange resin and eluted with water. The effluent was concentrated to a syrup that crystallized from ethanol. Recrystallization from water-ethanol gave 7, m.p. 89°-90° C.; [α] D 25 +88° (water). P.m.r. (D 2 O, 1% DSS): δ3.37-4.13 (m).
Anal. Calc. for C 6 H 12 O 6 .1/4H 2 O: C, 39.02; H, 6.82. Found: C, 39.00; H, 6.87.
Compound 7 had the same mobility as D-fructose, but lower mobility than L-sorbose on silica gel thin layer chromatography (3:1:1, v/v/v, methyl ethyl ketonemethanol-acetic acid). The peracetylated derivatives of D-fructose and compound 7 also had the identical mobility on silica gel thin layer chromatography (9:1, v/v, chloroform-acetone).
EXAMPLE 9
A solution of 9 (18.7 g) in pyridine (25 ml) was cooled in an ice bath and p-toluenesulfonyl chloride (50.8 g) in pyridine (75 ml) was added slowly. After being kept at room temperature for 2 days, ice was added and the mixture was extracted with chloroform (300 ml×2). The organic layer was washed twice with water, dried (Na 2 SO 4 ) and evaporated to a syrup (52.7 g, 100%), which was identified as 10.
Compound 10 (52.7 g) was stirred in 60% acetic acid (625 ml) at 55° C. for 2.5 hours. The solution was brought to pH of about 10 with 10N sodium hydroxide (625 ml) and heated at 40° C. for 3 hours. The reaction mixture was neutralized with 10N sulfuric acid (72 ml) and concentrated. The residue was triturated with ethanol (100 ml×3), filtered to removed much of the salt, and the ethanol solution was concentrated to a syrup. The residue was dissolved in ethanol (25 ml) and 10N sulfuric acid (100 ml) and heated at 80° C. for 30 minutes. The ethanol was evaporated off and the mixture was heated at 80° C. for 5 minutes. The reaction mixture was neutralized with 10N sodium hydroxide (100 ml) and the salt (Na 2 SO 4 ) was removed by precipitation with ethanol. After filtration, the filtrate was concentrated to a syrup of L-fructose in a 52% yield from the starting material.
EXAMPLE 10
Compound 10 was stirred in 30% acetic acid at 55° C. for 5 hours. The solution was brought to pH of about 10 with 10N sodium hydroxide and heated at 40° C. for 3 hours. The reaction mixture was acidified with 10N sulfuric acid and heated at 80° C. with stirring for 30 minutes. The reaction mixture was neutralized with 10N sodium hydroxide and the salt was removed by repeated precipitation with ethanol. After filtration, the filtrate was concentrated to give L-fructose as a syrup in more than 85% yield.
Methanesulfonyl chloride may be used in place of p-toluenesulfonyl chloride as shown in example 11.
EXAMPLE 11
Methanesulfonyl chloride (1.5 g) was added to a solution of 9 (1.2 g) in pyridine (2 ml). After being kept at room temperature for 2 days, ice was added and the mixture was extracted with chloroform. The organic layer was washed with water and evaporated to give methyl 4,6-O-isopropylidene-1,3-di-O-methanesulfonyl-α-L-sorbofuranoside as a syrup. The syrup was stirred in 60% acetic acid at 55° C. for 2.5 hours. The solution was brought up to pH about 10 with 10N sodium hydroxide and heated at 40° C. for 3 hours. The reaction mixture was neutralized with 10N sulfuric acid and concentrated. The residue was triturated with ethanol. After the salt was filtered off, the ethanol solution was concentrated and the residue was dissolved in a mixture of ethanol and 10N sulfuric acid (1:4). The solution was heated to 80° C. for 30 min. Ethanol was evaporated off and the mixture was heated for 5 minutes. The reaction mixture was neutralized with 10N sodium hydroxide and the salt was removed by repeated precipitation with ethanol. After filtration, the filtrate was concentrated to give L-fructose in more than 85% yield. | It is disclosed that L-fructose can be produced in high yield from L-sorbose. The process involves the inversion of the hydroxyl groups on carbon atoms C3 and C4 of L-sorbose to produce L-fructose. This inversion can be accomplished in simple, commercial equipment with the aid of common reagents. L-sorbose or an appropriately blocked derivative thereof is reacted so as to introduce or create a good leaving group, preferably mesyl or tosyl, at chiral carbon C3 thereby displacing the hydroxyl previously at that position. The leaving group is then displaced, preferably under alkaline conditions, in such a way that the hydroxyl oxygen atom at chiral carbon C4 attaches to chiral carbon C3, thereby displacing the leaving group while forming a 3,4-oxirane (epoxide) ring. The 3,4-oxirane ring forms in a downward position relative to the Haworth presentation thereby inverting chiral carbon C3 during formation of the 3,4-oxirane ring.
The 3,4-oxirane ring is then opened under acidic or alkaline conditions to yield a sugar ring with a hydroxyl group in a position above the sugar ring at chiral carbon C4, and a hydroxyl group in a downward position at C3.
Removal of any remaining blocking groups yields L-fructose. This may be accomplished by acid hydrolysis.
There are also disclosed novel classes of compounds which act as intermediaries in the synthesis of L-fructose. | Briefly summarize the invention's components and working principles as described in the document. | [
"BACKGROUND OF THE INVENTION There is a great need in the food industry for a sweet, zero calorie, non-toxic sugar.",
"An ideal example would be a nonmetabolizable fructose.",
"D-Fructose, the sweetest natural sugar, provides excellent organoleptic acceptance and mouth feel.",
"The United States uses over 23 billion pounds of sucrose per year and some of it is hydrolyzed to its constituent sugars namely one unit of D-glucose and one unit of D-fructose.",
"The mixture is commercially called invert sugar.",
"Since D-fructose is 1.7 times as sweet as sucrose, and D-glucose 0.7 times as sweet as sucrose, the total sweetness of invert sugar is higher than that of sucrose.",
"With the advent of enzyme engineering, it has become possible to convert D-glucose to an equilibrium mixture of D-glucose and D-fructose in a proportion of 54% to 46% respectively, and hence, produce the sweetness of invert sugar from low cost D-glucose, a product of the corn wet milling industry.",
"As a consequence, the use of fructose in the food industry has increased extensively.",
"With all of the desirable advances in producing the sweet sugar D-fructose, there has been no reduction in caloric value except for the lesser amount of D-fructose required to give the same sweetness as sucrose.",
"Both D-glucose and D-fructose are completely and equally metabolized in humans to produce equivalent caloric energy.",
"With the health need to take in less calories, some of the normal metabolic sugars should be replaced with other acceptable nonmetabolizable and non-toxic sweeteners.",
"This has been done with the development of synthetic sweeteners such as saccharin and aspartame.",
"However, a much more desirable sweetener is L-fructose which has the same sweetness as natural D-fructose.",
"It has no toxicity and seems not to be metabolized by humans, thus yielding no caloric value.",
"L-Fructose is the mirror image of D-fructose.",
"It has the same taste and most of the other properties of D-fructose but is not a substrate for the metabolic enzymes of the human system.",
"Examples of sweetened substrates which may be prepared with L-fructose can be found in U.S. Pat. No. 4,262,032 to Levin which is expressly incorporated herein.",
"This patent describes and claims the use of L-fructose and other L-hexose monosaccharides as sweetening agents.",
"L-Fructose, which has not been found in nature, was synthesized for the first time by Fischer.",
"See E. Fischer, Ber.",
", 23 (1890) 370-394.",
"DL-Glucose phenylosazone was prepared from α-acrose and hydrolyzed to the glycosulose, which was reduced to DL-fructose.",
"L-Fructose was isolated from the mixture.",
"L-Fructose was later synthesized by Wolfrom and Thompson from L-arabinonic acid in five steps.",
"See M. L. Wolfrom and A. Thompson, Methods of Carbohydr.",
"Chem.",
", 1 (1962) 118-120.",
"Recently, L-fructose was prepared by aldol condensation.",
"See S. Morgenlie, Carbohydr.",
"Res.",
", 107 (1982) 137-141.",
"DL-Glyceraldehyde condensed with 1,3-dihydroxy-2-propanone catalyzed by Dowex 1 (OH - ) resin to give a hexulose mixture.",
"Crystallization of the mixture from methanol yielded 54% of DL-fructose.",
"Treatment of the DL-fructose mixture with baker's yeast gave a product from which 62% of 2,3:4,5-di-O-isopropylidene-β-L-fructopyranose was isolated after acetonation.",
"When L-glyceraldehyde was used as starting material, 2,3:4,5-di-O-isopropylidene-β-L-fructopyranose was isolated in 60-65% yield after acetonation of the hexulose mixture.",
"L-Fructose has been prepared enzymatically from L-mannose by an isomerase present in cell-free extracts of Aerobacter aerogenes grown on L-mannose to give L-fructose in 28-32% yield.",
"See J. W. Mayo and R. J. Anderson, Carbohydr.",
"Res.",
", 8 (1968) 344-347.",
"Both chemical and enzymic procedures either are too elaborate or require relatively expensive starting material.",
"To commercialize L-fructose as a sweetener requires a low cost process.",
"A simple method for the synthesis of L-fructose which starts with L-sorbose, a relatively inexpensive industrial chemical would be desirable.",
"The only structural difference between L-sorbose and L-fructose is the reverse configuration of the hydroxyl groups at C-3 and C-4.",
"SUMMARY OF THE INVENTION It has now been discovered that L-fructose can be produced in high yield from L-sorbose.",
"The process is simple and convenient to conduct.",
"The process involves the inversion of the hydroxyl groups on carbon atoms C3 and C4 of L-sorbose to produce L-fructose.",
"This inversion can be accomplished in simple, commercial equipment with the aid of common reagents.",
"In accordance with the present invention, L-sorbose or an appropriately blocked derivative thereof is reacted so as to introduce a good leaving group, preferably mesyl or tosyl, at chiral carbon C3 thereby replacing the proton of the hydroxyl previously at that position.",
"The leaving group is then displaced, preferably under alkaline conditions, in such a way that the hydroxyl oxygen atom at chiral carbon C4 attaches to chiral carbon C3, thereby displacing the leaving group while forming a 3,4-oxirane (epoxide) ring.",
"The 3,4-oxirane ring forms in a downward position relative to the Haworth representation in which the ring oxygen atom is to the right and behind the plane of the paper thereby inverting chiral carbon C3 during formation of the 3,4-oxirane ring.",
"The 3,4-oxirane ring is then opened under acidic or alkaline conditions to yield a sugar ring with a hydroxyl group in a position above the sugar ring at chiral carbon C4, and a hydroxyl group in a downward position at C3.",
"Removal of any remaining blocking groups yields L-fructose.",
"This may be accomplished, for example, by acid hydrolysis.",
"Also, in accordance with the above-described process, two novel classes of compounds are disclosed which act as intermediaries in the synthesis of L-fructose.",
"These are a 3,4-anhydro-L-sorbose having the formula: ##STR1## wherein R 1 represents a good leaving group, R 2 represents a (lower)alkyl group, or R 1 and R 2 both are attached to a good leaving group and an L-sorbofuranose derivative selected from those having the formulas ##STR2## wherein R 1 represents a good leaving group, R 2 and R 3 represent hydrogen or together are attached to a good leaving group, R 4 represents a (lower)alkyl group, R 5 represents a good leaving group, or R 4 and R 5 taken together represent a (lower)divalent hydrocarbon group.",
"DETAILED DESCRIPTION OF THE INVENTION There are several modifications of L-sorbose that can serve as starting materials for the conversion.",
"Each is easily made and serves well in the conversion process.",
"Each can be made by any of several well known processes.",
"Among such convenient starting materials are methyl L-sorbofuranoside, 1,2-O-isopropylidene-L-sorbofuranose, 1,2-O-isopropylidene-L-sorbopyranose, 2,3-O-isopropylidene-L-sorbofuranose, 2,3-O-isopropylidene-L-sorbopyranose, 1,3-O-isopropylidene-L-sorbofuranose, 1,3-O-isopropylidene-L-sorbopyranose, 1,2:4,6-di-O-isopropylidene-L-sorbofuranose, 2,3:4,6-di-O-isopropylidene-L-sorbofuranose, 1,3:4,6-di-O-isopropylidene-L-sorbofuranose, methyl 4,6-O-isopropylidene-L-sorbofuranoside, ethyl 4,6-O-isopropylidene-L-sorbofuranoside, methyl 1,3:4,6-di-O-isopropylidene-L-sorbofuranoside, and ethyl 1,3:4,6-di-O-isopropylidene-L-sorbofuranoside.",
"Other appropriately blocked starting materials, such as appropriately blocked L-sorbofuranosides, will be apparent to those knowledgeable in carbohydrate chemistry.",
"The isopropylidene blocking group can be prepared in many ways using a variety of reagents, such as acetone and 2,2-dimethoxypropane.",
"The isopropylidene blocking group can be replaced by other blocking groups, such as benzylidene, ethylidene, sec.",
"butylidene and cyclohexylidene.",
"Each of the starting materials can be derivatized at position C3 with a good leaving group such a tosyl, mesyl or other, such that on treatment under alkaline condition, as for example with sodium hydroxide or sodium methoxide, the leaving group can be displaced by the oxygen atom of the hydroxyl group at C4 to produce a three membered 3,4-oxirane ring wherein the 3,4-oxirane ring is below the sugar ring as it is in Haworth representation with the epoxide oxygen bonds being on the right side of the sugar if it were written upright in a normal Fischer projection.",
"The formation of this particularly designed 3,4-oxirane ring rather than one of another steric arrangement is a prime discovery of this invention, for not only is the ring in correct position for the next conversion step, it is obtained in nearly 100% yield.",
"The next and last conversion step is to hydrolytically open the 3,4-oxirane ring with either acid or base to produce L-fructose or an L-fructose derivative which on acid treatment will yield L-fructose.",
"Another discovery of merit, in the conversion, is the finding that the 3,4-oxirane ring opens specifically in the correct direction maintaining chiral configuration at carbon C3 while inverting chirality at carbon C4.",
"The process for converting L-sorbose to L-fructose is especially useful because it has been discovered that it is possible to treat an appropriate derivative of L-sorbose so as to introduce in high yield a good leaving group at chiral carbon C3 and to displace this group in such a way to give nearly 100% yield of a 3,4-oxirane ring involving chiral carbon C3 and C4 with concommitant inversion of chiral carbon atom C3.",
"The process is also most useful because of the finding that the 3,4-oxirane produced as described above can be opened in nearly 100% yield in such a manner that the chiral carbon atom at C4 is inverted by introduction of a hydroxyl group from the top side of the ring at C4 and hence, opposite to the oxygen bond at C4 involved in the 3,4-oxirane ring formation.",
"Various good leaving groups can be introduced at chiral carbon C3 of an L-sorbose derivative.",
"P-Toluenesulfonyl (tosyl) and methylsulfonyl (mesyl) are preferred with mesyl especially preferred because of its low cost and ease of recovery and recycle.",
"The entire process of converting L-sorbose or an appropriately blocked L-sorbose derivative to L-fructose is amazingly low cost involving introducing the appropriate leaving group at chiral carbon C3, treating with alkali and then with acid.",
"Both the alkali treatment and acid treatment can be conducted in the same reaction vessel without isolation or purification of the intermediate 3,4-oxirane derivative.",
"If good leaving groups are introduced at other positions than chiral carbon atom C3, no harm occurs since they will be hydrolyzed and removed in the last acid treatment step.",
"It is preferred that a leaving group not be attached to carbon atom C4 or to another carbon where it can adversely effect the desired 3,4-oxirane ring formation at C3 and C4.",
"A preferred embodiment may be illustrated by the following reaction scheme: ##STR3## In this first preferred embodiment, L-fructose (7) is synthesized from L-sorbose (1) via a 1,2:4,6-di-O-isopropylidene-α-L-sorbofuranose (2) intermediate.",
"L-Sorbose can react with acetone or 2,2-dimethoxypropane to produce 2.",
"1,2:4,6-Di-O-isopropylidene-α-L-sorbofuranose (2), a kinetic product in the isopropylidenation of L-sorbose, is formed normally in about 5% yield.",
"However, using tin(II) chloride as a catalyst, 2 can be obtained in greater than 80% yield as indicated by thin layer chromatography.",
"The reaction is slow unless a small amount of 1,2-dimethoxyethane or acetone is present to improve the solubility of tin(II) chloride.",
"1,2-Dimethoxyethane is preferred for highest yield.",
"If acetone replaces 1,2-dimethoxyethane as a solvent, the yield may be somewhat lower.",
"The yield can still be maintained high, however, by keeping the proportion of acetone in the reaction mixture as low as possible.",
"A small amount of acetone is required as solvent for the reaction because tin(II) chloride is not soluble in 2,2-dimethoxypropane.",
"Compound 2 is then reacted with methanesulfonylchloride.",
"Mesylation of 2 is complete in 1-4 hours to yield 1,2:4,6-di-O-isopropylidene-3-O-mesyl-α-L-sorbofuranose (3) in 83% yield.",
"Compound 3 crystallizes readily from the reaction mixture upon the addition of water.",
"Preferably, compound 3 is prepared from L-sorbose without isolation of the intermediate 2.",
"The 4,6-O-isopropylidene protecting group of 3 is selectively removed to yield 1,2-O-isopropylidene-3-O-mesyl-α-L-sorbofuranose (4) by addition of either a mixture of acetone and 0.25% aqueous sulfuric acid at 25° C. or 60% acetic acid at 40° C. The sulfuric acid reagent is better in terms of the cost and simplification of the process.",
"A small amount of by-product, likely 3-O-mesyl-L-sorbose, is also detected, particularly in the 0.25% sulfuric acid medium.",
"Compound 4 is crystallized from the reaction mixture after most of the acetone is removed.",
"Formation of the 3,4-anhydro ring is readily achieved in alkaline condition at 25° C. to yield 5.",
"The alkali concentration and/or the proportion of methanol in the reaction mixture is critical.",
"For example, when a solution of 4 in methanol (100 ml) and 1N sodium hydroxide (70 ml) is heated at 45° C. for 5 hours, only a very small amount of 4 is converted to 5.",
"Opening of the anhydro ring, however, is more difficult.",
"Ring opening is completed in strong, aqueous alkaline solution by heating 3 days at 70°-80° C. A small amount of by-product is detected.",
"On the other hand, a solution of 4 in 5% aqueous potassium hydroxide solution, refluxed for 3 hours, gives 6 as a single product.",
"Removal of the 1,2-O-isopropylidene group from 6 by acid hydrolysis gives 7 as the major product.",
"L-Fructose can be derivatized according to reported procedures to yield 8.",
"See S. Morgenlie, Carbohydrate.",
"Res.",
", 107 (1982) 137-141.",
"Compound 8 had the same m.p. and optical rotation as reported in the literature.",
"A second preferred embodiment for producing L-fructose from L-sorbose utilizes methyl 4,6-O-isopropylidene-1-3-di-O-tolysulfonyl-α-L-sorbofuranoside (10) as an intermediate.",
"This second preferred embodiment may be illustrated by the following reaction scheme.",
"##STR4## Methyl 4,6-O-isopropylidene-α-L-sorbofuranoside (9) is prepared in one step following reported procedures.",
"See T. Maeda, K. Tori, S. Satoh and K. Tokuyama, Bull.",
"Chem.",
"Soc.",
"Japan, 41 (1968) 2495-2503.",
"Compound 9 is then reacted with a solution containing p-toluenesulfonyl chloride.",
"Tosylation of 9 is complete in two days to give 10 and a trace amount of methyl 4,6-O-isopropylidene-1-O-p-tolysulfonyl-α-L-sorbo-furanoside.",
"The isopropylidene group of 10 is readily removed in 60% acetic acid solution to give 11.",
"The reaction mixture is made alkaline to form a 3,4-anhydro-ring by intramolecular nucleophilic displacement of the sulfonyloxy group.",
"The alkali concentration and/or the proportion of methanol in the reaction mixture is critical.",
"For example, when a solution of 11 in methanol (100 ml) and 1N sodium hydroxide (70 ml) is heated at 45° C. for 5 hours, only a very small amount of 11 is converted to 12.",
"The conditions required for alkaline scission of three membered anhydro-rings are, in general, more drastic than the conditions used for ring closure.",
"No anhydro-ring opening is detected under the alkaline conditions used in this latter reaction.",
"Under milder, acidic conditions, 12 is converted to 13.",
"The anhydro-ring is hydrolyzed but the glycosidic bond and the sulfonyl ester linkage survive.",
"The p-toluenesulfonyl ester linkage is relatively resistant to acid hydrolysis with the glycosidic bond stabilized by the inductive effect from the adjacent sulfonyl ester group.",
"Because of the difficulty in cleaving the sulfonyl ester linkage, a high concentration of sulfuric acid (10N) is employed.",
"The anhydro-ring opens exclusively at C4.",
"This apparently favors the development of a positive charge at C4 rather than at C3 because of the inductive effect from the substituents at C1 and C2.",
"The major product from the acid hydrolysis is L-fructose (7).",
"Some minor products are also detected.",
"Crystalline 7 shows an optical rotation of about +60° within 30 minutes after dissolution.",
"The optical rotation raises to +88° after 48 hours at 25° C. The increase in optical rotation indicates that the crystalline material is a β-L-anomer.",
"L-Fructose (7), when subjected to a tasting panel for sweetness is found to be as sweet as D-fructose.",
"The following Examples illustrate the procedures described in the first embodiment.",
"1,2:4,6-Di-O-isopropylidene-3-O-mesyl-α-L-sorbofuranose (3) was prepared as follows.",
"EXAMPLE 1 L-Sorbose (1, 8.24 g) was suspended in 1,2-dimethoxyethane (25 ml) containing tin(II) chloride (10 mg) and 2,2-dimethoxypropane (13.4 ml) was added.",
"The mixture was refluxed, with stirring, for 2 hours until the solution was clear.",
"A drop of pyridine was added and the mixture was concentrated to a syrup.",
"The syrup was dissolved in chloroform and washed with water.",
"The chloroform fraction was dried (Na 4 SO 4 ) and evaporated to a syrup.",
"The syrup was extracted with hot petroleum ether.",
"Crystallization occurred from the cooled extract.",
"Recrystallization from petroleum ether gave 2 (4.88 g, 41%), m.p. 71°-73°, [α] D 25 -24.7° (c 1.029, acetone);",
"literature m.p. 72°-73° 8 α] D 25 -23.9.",
"The mass spectrum showed the largest fragment ion at m/e 245 (M + -CH 3 ).",
"Anal.",
"Calc.",
"for C 12 H 20 O 6 ;",
"C, 55.37;",
"H, 7.75.",
"Found: C, 54.93;",
"H, 7.67.",
"To a solution of 2 (0.7 g) in pyridine (1 ml), cooled in an ice bath, was added methanesulfonyl chloride (0.31 ml).",
"After 1 hour, ice was added and the white crystalline material was washed with water to give 3 (0.76 g, 83.5%).",
"EXAMPLE 2 L-Sorbose (30 g) was suspended in 2,2-dimethoxypropane (90 ml).",
"1,2-Dimethoxyethane (3 ml) containing tin(II) chloride (150 mg) was added.",
"The mixture was refluxed, with stirring, for 2 hours until the solution was clear and then evaporated to a syrup.",
"The syrup was dissolved in pyridine (60 ml) and cooled in an ice bath.",
"Methanesulfonyl chloride (19.4 ml) was added.",
"After storage in refrigerator for 16 hours and then at 25° C. for 4 hours, water (1000 ml) was added.",
"The crystals produced were collected by filtration to give 3 (28.9 g, 51%).",
"Recrystallization from ethanol gave 3 as colorless needles, m.p. 123°-124° C. Anal.",
"Calc.",
"for C 13 H 22 O 8 S: C, 46.14;",
"H, 6.56;",
"S, 9.48.",
"Found: C, 46.25;",
"H, 6.70, S, 9.11.",
"EXAMPLE 3 L-Sorbose (10 g) was suspended in 2,2-dimethoxypropane (30 ml).",
"1,2-Dimethoxyethane (1 ml) containing tin(II) chloride (30 mg) was added.",
"The mixture was refluxed, with stirring, for 2.5 hours until the solution became clear.",
"It was then evaporated to a syrup.",
"The syrup was dissolved in pyridine (20 ml) and cooled in an ice bath.",
"Methanesulfonyl chloride (6.45 ml) was added slowly.",
"After storage at room temperature for 2.5 hours, water (400 ml) was added.",
"Crystals produced were collected by filtration to give 3 (8.63 g, 46%).",
"EXAMPLE 4 L-Sorbose (4.122 g) was suspended in 2,2-dimethoxypropane (13.2 ml).",
"Acetone (1 ml) containing tin(II) chloride (15 mg) was added.",
"The mixture was refluxed, with stirring, for 100 minutes until the solution became clear.",
"It was then evaporated to a syrup.",
"The syrup, dissolved in pyridine, (8.2 ml) was cooled in an ice bath.",
"Methanesulfonyl chloride (2.66 ml) was added slowly.",
"After storage at room temperature for 2.5 hours, water (200 ml) was added.",
"Produced crystals were collected by filtration to give 3 (3.08 g, 40%).",
"L-Fructose was prepared from compound 3 as shown in the following examples.",
"EXAMPLE 5 Compound 3 (2.5 g) was dissolved in acetone (20 ml) and 0.25% sulfuric acid in water (15 ml) was added.",
"After storage at room temperature for 24 hours, the solution was made alkaline with a 9N sodium hydroxide solution (2 ml).",
"The solution was then heated at 70°-80° C. for 48 hours, acidified with 18N sulfuric acid solution (1 ml), heated at 70°-80° C. for 20 minutes and then neutralized with 2N sodium hydroxide solution (5 ml).",
"The mixture was taken to dryness and the residue extracted with ethanol (40 ml).",
"The ethanol solution was concentrated to give L-fructose as a syrup (0.97 g, 73%).",
"The syrup was contaminated with a small amount of by-products with lower mobility than L-fructose on silica gel thin layer chromatography.",
"The mixture was purified on a silica gel column (4:1:0.7, v/v/v, ethyl acetatemethanol-water) to give a syrup product (0.83 g, 62%).",
"EXAMPLE 6 Compound 3 (3 g) dissolved in 60% acetic acid (30 ml) was heated at 40° C. for 3 hours.",
"The mixture was made alkaline with 10N sodium hydroxide solution (40 ml), heated at 70° C. for 15 hours and then acidified with 18N sulfuric acid solution (30 ml).",
"The salt was filtered off and the filtrate left at room temperature for 18 hours and 70° C. for 2 hours.",
"The mixture was neutralized with 10N sodium hydroxide solution (3.5 ml).",
"The salt was removed by ethanol precipitation.",
"After filtration, the filtrate was concentrated, deionized with a column of Amberlite MG-1 ion-exchange resin, and eluted with water.",
"The effluent was concentrated to give L-fructose as a syrup (1.21 g, 76%).",
"EXAMPLE 7 Compound 3 (1 g) is dissolved in acetone (10 ml) and 0.24% sulfuric acid in water (10 ml) is added.",
"After storage at room temperature for 16 hours, the solution is neutralized with solid sodium hydrogencarbonate and filtered.",
"Acetone is removed by evaporation until crystallization occurs to give 1,2-O-isopropylidene-3-O-mesyl-α-L-sorbofuranose.",
"The crystalline material is dissolved in 5% potassium hydroxide (30 ml) and refluxed for 2.5 hours.",
"The mixture is acidified to pH about 2 with 25% sulfuric acid in water.",
"After storage at room temperature for 16 hours until the reaction is complete, the mixture is neutralized with 50% potassium hydroxide in water and taken to dryness.",
"The residue is extracted with ethanol and the ethanol solution is concentrated to give L-fructose as a syrup.",
"The syrup is deionized with a column of Amberlite MB-1 ion exchange resin.",
"The following examples illustrate the procedures for preparing L-fructose from L-sorbose by means of intermediate 10.",
"EXAMPLE 8 L-Sorbose (1, 40 g) was refluxed in 2,2-dimethoxypropane (100 ml) containing p-toluenesulfonic acid (500 mg) for 2 hours.",
"The mixture was neutralized with a slight excess of methanolic sodium methoxide and concentrated to a syrup.",
"The syrup was extracted with benzene (2×50 ml) and the benzene fraction was extracted with water (3×50 ml).",
"The aqueous fraction saturated with sodium chloride was extracted with chloroform (3×100 ml).",
"The chloroform was evaporated and the residue chromatographed on a silica gel column, eluted with 9:1 (v/v) hexane-acetone.",
"Compound 9 was isolated as a crystalline material (1.6 g, 3.1%);",
"R f (thin layer chromatography on silica gel in 9:1, v/v, chloroformacetone) 0.26.",
"Recrystallization from ether gave 2, m.p. 109°-110° C.;",
"lit.",
"m.p. 108°-109° C. Anal.",
"Calc.",
"for C 10 H 18 O 6 : C, 51.27;",
"H, 7.75.",
"Found: C, 51.98;",
"H, 7.99.",
"A solution of 9 (1.2 g) in pyridine (1.8 ml) was cooled in an ice bath and p-toluenesulfonyl chloride (3.3 g) in pyridine (5 ml) was added slowly.",
"After storage at 25° C. for 2 days, ice was added and the mixture was extracted with chloroform (2×20 ml).",
"The organic layer was washed twice with water, dried (Na 2 SO 4 ) and evaporated to a syrup.",
"Traces of pyridine in the residue were removed by co-evaporation with toluene to give 10 as a syrup (2.9 g, 100%), which was chromatographically pure;",
"R f (thin layer chromatography on silica gel in 9:1, v/v, chloroform-acetone) 0.80;",
"[α] D 25 +6° (c 2.5, chloroform).",
"The mass spectrum showed the largest fragment ion at m/e 527 (M-CH 3 );",
"P.m.r. (CDCl 3 );",
"δ7.20-7.85 (m, 8H, 2C 6 H 4 CH 3 ), 3.60-4.63 (m, 7H, H-1, - 3, -4, -5, -6), 3.17 (s, 3H, OCH 3 ), 2.43, 2.41 (s, s, 6H, 2C 6 H 4 CH 3 ) and 1.25, 1.15 (s, s, 6H, 2C(CH 3 ) 2 ).",
"Anal.",
"Calc.",
"for C 24 H 30 O 10 S 2 : C, 53.13;",
"H, 5.57;",
"S, 11.82.",
"Found: C, 53.21;",
"H, 5.51;",
"S, 11.74.",
"Compound 10 (2.3 g) was stirred in 60% acetic acid solution (23 ml) at 55° C. for 2.5 hours.",
"The pH of the solution was raised to 5-6 with 10N sodium hydroxide solution and the mixture was extracted with chloroform (2×50 ml).",
"The chloroform was evaporated to give 11 as a syrup (2 g, 94%);",
"R f (thin layer chromatography on silica gel in 9:1, v/v, chloroform-acetone) 0.25;",
"[α] D 25 -46° (c 1.8, chloroform).",
"P.m.r. (CDCl 3 ): δ7.06-7.85 (m, 8H, 2C 6 H 4 CH 3 ), 3.40-4.80 (m, 7H, H-1, -3, -4, -5, -6), 3.20 (s, 3H, OCH 3 ) and 2.40, 2.37 (s, s, 6H, 2C 6 H 4 CH 3 ).",
"Anal.",
"Calc.",
"for C 21 H 26 O 10 S 2 : C, 50.19;",
"H, 5.22;",
"S, 12.76.",
"Found: C, 50.39;",
"H, 5.48;",
"S, 12.90.",
"To a solution of 11 (1.43 g) in methanol (1 ml) was added 2N sodium hydroxide solution (1 ml).",
"After 2 hours at 40° C., 11 was converted to a single product, which showed positive in a vicinal epoxide test.",
"Methanol (20 ml) was added and the solution was neutralized with 5N sulfuric acid solution.",
"The salt was filtered and water (10 ml) was added.",
"After evaporating the methanol, the aqueous solution was extracted with chloroform (2×50 ml).",
"The chloroform was evaporated off to give 12 as a syrup (0.85 g, 90%);",
"[α] D 25 -27° (c 2.5, chloroform).",
"P.m.r. (CDCl 3 );",
"δ7.10-7.87 (m, 4H, C 6 H 4 CH 3 ), 3.50-4.30 (m, 7H, H-1, -3, -4, -5, -6), 3.17 (s, 3H, OCH 3 ) and 2.40 (s, 3H, C.sub.",
"6 H 4 CH 3 ).",
"Anal.",
"Calc.",
"for C 14 H 18 O 7 S: C, 50.90;",
"H, 5.49;",
"S, 9.17.",
"Found: C, 50.76;",
"H, 5.84;",
"S, 9.47.",
"A solution of 12 (0.29 g) in a small amount of methanol was acidified with 1N sulfuric acid solution to pH 2-3.",
"After storage at 25° C. for 2 days, 12 was cleanly converted to a single product.",
"The mixture was neutralized with 1N sodium hydroxide solution and extracted with chloroform.",
"The organic fraction was concentrated and the residue chromatographed on a silica gel column.",
"Elution with 9:1 (v/v) chloroform-acetone gave 13 as a syrup (0.29 g, 95%).",
"The mass spectrum showed the highest peak at m/e 317 (M--OCH 3 ).",
"P.m.r. (CDCl 3 ): δ7.10-7.83 (m,4H, C 6 H 4 CH 3 ), 3.40-4.30 (m,7H, H-1, -3, -4, -5, -6), 3.23 (s, 3H, OCH 3 ) and 2.43 (s, 3H, C 6 H 4 CH 3 ).",
"To a solution of 13 (7.5 g) in ethanol (50 ml) was added 10N sulfuric acid solution (125 ml).",
"The mixture was heated at 70° C. for 1 hour and neutralized with 10N sodium hydroxide solution.",
"After addition of ethanol and filtering off the salts the filtrate was concentrated.",
"The residue was chromatographed on a silica gel column.",
"Elution with 4:1:0.7 (v/v/v) ethyl acetate-methanol-water gave 7 as a syrup (3.6 g, 88%).",
"The syrup was de-ionized with a column of Amberlite MB-1 ion-exchange resin and eluted with water.",
"The effluent was concentrated to a syrup that crystallized from ethanol.",
"Recrystallization from water-ethanol gave 7, m.p. 89°-90° C.;",
"[α] D 25 +88° (water).",
"P.m.r. (D 2 O, 1% DSS): δ3.37-4.13 (m).",
"Anal.",
"Calc.",
"for C 6 H 12 O 6 [.",
"].1/4H 2 O: C, 39.02;",
"H, 6.82.",
"Found: C, 39.00;",
"H, 6.87.",
"Compound 7 had the same mobility as D-fructose, but lower mobility than L-sorbose on silica gel thin layer chromatography (3:1:1, v/v/v, methyl ethyl ketonemethanol-acetic acid).",
"The peracetylated derivatives of D-fructose and compound 7 also had the identical mobility on silica gel thin layer chromatography (9:1, v/v, chloroform-acetone).",
"EXAMPLE 9 A solution of 9 (18.7 g) in pyridine (25 ml) was cooled in an ice bath and p-toluenesulfonyl chloride (50.8 g) in pyridine (75 ml) was added slowly.",
"After being kept at room temperature for 2 days, ice was added and the mixture was extracted with chloroform (300 ml×2).",
"The organic layer was washed twice with water, dried (Na 2 SO 4 ) and evaporated to a syrup (52.7 g, 100%), which was identified as 10.",
"Compound 10 (52.7 g) was stirred in 60% acetic acid (625 ml) at 55° C. for 2.5 hours.",
"The solution was brought to pH of about 10 with 10N sodium hydroxide (625 ml) and heated at 40° C. for 3 hours.",
"The reaction mixture was neutralized with 10N sulfuric acid (72 ml) and concentrated.",
"The residue was triturated with ethanol (100 ml×3), filtered to removed much of the salt, and the ethanol solution was concentrated to a syrup.",
"The residue was dissolved in ethanol (25 ml) and 10N sulfuric acid (100 ml) and heated at 80° C. for 30 minutes.",
"The ethanol was evaporated off and the mixture was heated at 80° C. for 5 minutes.",
"The reaction mixture was neutralized with 10N sodium hydroxide (100 ml) and the salt (Na 2 SO 4 ) was removed by precipitation with ethanol.",
"After filtration, the filtrate was concentrated to a syrup of L-fructose in a 52% yield from the starting material.",
"EXAMPLE 10 Compound 10 was stirred in 30% acetic acid at 55° C. for 5 hours.",
"The solution was brought to pH of about 10 with 10N sodium hydroxide and heated at 40° C. for 3 hours.",
"The reaction mixture was acidified with 10N sulfuric acid and heated at 80° C. with stirring for 30 minutes.",
"The reaction mixture was neutralized with 10N sodium hydroxide and the salt was removed by repeated precipitation with ethanol.",
"After filtration, the filtrate was concentrated to give L-fructose as a syrup in more than 85% yield.",
"Methanesulfonyl chloride may be used in place of p-toluenesulfonyl chloride as shown in example 11.",
"EXAMPLE 11 Methanesulfonyl chloride (1.5 g) was added to a solution of 9 (1.2 g) in pyridine (2 ml).",
"After being kept at room temperature for 2 days, ice was added and the mixture was extracted with chloroform.",
"The organic layer was washed with water and evaporated to give methyl 4,6-O-isopropylidene-1,3-di-O-methanesulfonyl-α-L-sorbofuranoside as a syrup.",
"The syrup was stirred in 60% acetic acid at 55° C. for 2.5 hours.",
"The solution was brought up to pH about 10 with 10N sodium hydroxide and heated at 40° C. for 3 hours.",
"The reaction mixture was neutralized with 10N sulfuric acid and concentrated.",
"The residue was triturated with ethanol.",
"After the salt was filtered off, the ethanol solution was concentrated and the residue was dissolved in a mixture of ethanol and 10N sulfuric acid (1:4).",
"The solution was heated to 80° C. for 30 min.",
"Ethanol was evaporated off and the mixture was heated for 5 minutes.",
"The reaction mixture was neutralized with 10N sodium hydroxide and the salt was removed by repeated precipitation with ethanol.",
"After filtration, the filtrate was concentrated to give L-fructose in more than 85% yield."
] |
CROSS-REFERENCE TO RELATED APPLICATION DATA
This application is a continuation-in-part of U.S. patent application Ser. No. 12/032,876, filed Feb. 18, 2008, which is a continuation of U.S. patent application Ser. No. 10/904,486, filed Nov. 12, 2004, now U.S. Pat. No. 7,344,267.
BACKGROUND OF THE INVENTION
The present invention relates to illuminated toy balloons. More particularly, the present invention relates to improved switch arrangements for illuminated balloon inflators. The use of lights in association with balloons is well known. Examples include U.S. Pat. Nos. 6,390,651 and 5,215,492. Also well known is the use of chemiluminescent materials or light sticks that produce light by chemical reaction which may be inserted into balloons.
The present invention is an improvement over the known illuminated balloons in which an inexpensive, self-powered apparatus is inserted into the neck of a balloon, which contains a small, energy-efficient light source powered by a battery, and which includes a switch in the interior of the balloon to turn the light on and off.
While such illuminated balloons are known and function well, actuation of the switch can be difficult when it is located within the interior of the balloon.
Accordingly, there is a need for an illuminated balloon inflator in which the illuminated inflator apparatus is inserted in the balloon, the balloon then filled with a gas such as helium or air, and the light is easily switched on or off as desired.
SUMMARY OF THE INVENTION
An illuminated inflator for inserting into the neck of a balloon includes a gas-tight flange having a periphery, a center, and upper and lower surfaces. A filler tube has upper and lower ends and extends through the flange, with the lower end of the filler tube extending below the lower surface the flange and the upper end of the filler tube extending above the upper surface of the flange. A one-way valve is in flow communication with the filler tube.
A light assembly includes a power source and at least one light element electrically connected to the power source. The light assembly is operably mounted to the flange at the upper surface thereof.
A switch is operably connected to the power source and the at least one light element for providing power to and isolating power from the at least one light element. The inflator is inserted into the balloon with the flange in the neck of the balloon defining a pressure region boundary. The bottom of the filler tube extends outside of the pressure region boundary for filling the balloon with a gas, such that the one-way valve prevents gas from escaping from the pressure region boundary through the filler tube. The switch is mounted to the inflator outside of the pressure region boundary to allow actuation/access to the switch without access to the pressure boundary and without contacting the balloon. The inflator includes an electrical connector extending between the switch and light assembly.
The light assembly is mounted to and spaced from the gas-tight flange. In a present embodiment, three legs extend between the gas-tight flange and the light assembly to elevate the light assembly into the balloon. A present light element is an LED, preferably multiple (three) LEDs. Circuitry is used to provide steady illumination, blinking illumination and flashing (e.g., a variety of illumination operating modes) of the LEDs.
The switch, which is external to the pressure boundary, can be mounted to the filler tube or to a lower surface of the flange to allow access to the switch without access to the pressure boundary and without contacting the balloon.
An opening in the lower flange accommodates the connectors (wires) and is sealed after placement/penetration of the connectors to assure the integrity of the pressure boundary.
These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein:
FIG. 1 depicts a perspective view of a balloon containing the apparatus for illuminating the balloon interior.
FIG. 1A depicts a detail perspective view derived from FIG. 1 , showing the apparatus in greater detail.
FIG. 2A depicts a light element assembly containing a battery.
FIG. 2B depicts a perspective view of an embodiment of the apparatus using magnetic means to affix the light element to the plug.
FIG. 3 depicts a perspective view of the embodiment of FIG. 2 b , in which the light element assembly is magnetically affixed to the magnet.
FIG. 4A depicts an embodiment of the present invention in which the light element is affixed by means of barbs.
FIG. 4B depicts an embodiment of the present invention in which the light element is affixed by means of restraint fingers.
FIG. 4C depicts an embodiment in which the pressure of gas in the balloon switches on and off the lighting element, in the “off” position.
FIG. 4D depicts an embodiment in which the pressure of gas in the balloon switches on and off the lighting element, in the “on” position.
FIG. 5A depicts a prior-art balloon inflation device in cross section elevation view.
FIG. 5B depicts a prior-art balloon inflation device in top plan view.
FIG. 6A depicts an embodiment of a lighted balloon inflation device in cross section elevation view.
FIG. 6B depicts the embodiment of FIG. 6A in top plan view.
FIGS. 7A-7C illustrates alternate embodiments of the illuminated inflator device.
DETAILED DESCRIPTION OF THE INVENTION
While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated.
It should be further understood that the title of this section of this specification, namely, “Detailed Description Of The Invention”, relates to a requirement of the United States Patent Office, and does not imply, nor should be inferred to limit the subject matter disclosed herein.
Referring to FIG. 1 , the present device 16 is inserted into the neck of a balloon, with a cord 3 attached to the device restraining the balloon. The balloon is obviously filled with a gas, which may be air, helium, or similarly inert gasses, in the case of balloons used as toys, on account of safety concerns. In other applications, where sufficient safeguards are taken, the gas need not be inert.
Referring now to FIG. 1A , the details of this device are revealed. The device, in the form of a plug, contains a cylindrical body 3 which has an integrally formed radially extending flange 7 which retains the device within the balloon. When the device is inserted into the neck 14 of the balloon, the flange 7 causes the neck to provide a gas-tight seal just above the neck ring 15 at the lower end of the neck, which provides stability for the balloon with the device inserted.
Still referring to FIG. 1A , a light-emitting assembly is shown disposed above the flange 7 . The assembly is made up of the light emitting surface 13 , which is rigidly affixed to a screw-on cap 12 , which attaches to the lower assembly housing 11 . A battery which powers the light-emitting assembly is contained within the lower housing and screw-on cap. The user may turn the light on and off by screwing the cap down, and conversely screwing the cap in the opposite direction, relieving pressure and disconnecting power to the light element.
In the embodiment shown in FIG. 1A the light-emitting assembly is restrained in place by guides 8 . Also contained in this embodiment is a magnet, not shown in this view, which is disposed below the base of the light-emitting assembly.
The use of the magnet in this embodiment may be further understood by referring next to FIGS. 2A , 2 B, and 3 . FIGS. 2A and 2B depict the light-emitting assembly separated from the rest of the device. The battery 12 , is clearly displayed in this figure, disposed entirely within the guides 8 , and concentrically disposed directly upon the flange 7 . FIG. 3 shows the two elements combined to form the device prior to insertion into the balloon. Still referring to these figures, the light-emitting assembly is mounted on the flange between the guides 8 , and restrained in place by the magnet 10 , which attracts the steel body of the light-emitting assembly 9 . The body 4 of the device is in the form of a tube, or cylinder, which is hollow, containing a cylindrical chamber 5 and ending in a tab 6 , which provides a hole to which a cord may be attached.
In order to use the device, the balloon may first be filled, typically with helium, so that the balloon floats in the air. In one embodiment the balloon is first filled with helium by means well known in the prior art, and which are not a part of this invention. The user pinches off the neck to retain the helium within the balloon, and then quickly inserts the device into the neck of the balloon. Once the insertion has been accomplished, the flange 7 provides a seal so that the helium will not escape from the balloon, except at a very, very slow rate.
In another variation of this invention, the device may contain a one-way valve, or check valve, permitting the helium to be inserted through the cylindrical chamber 5 , but not allowing the helium to escape back through the chamber. In this embodiment the valve is located in the body of the device. Ports (not shown) are provided between the valve and the head of the device to allow the helium to enter the balloon, but not escape.
In this embodiment the device is first inserted into the balloon neck, as shown in FIG. 1 , before filling. The helium gas is then pumped in through the cylindrical channel 5 of the body 4 , which allows the balloon to fill, until the gas is shut off, relieving the pressure in the channel, and causing the check valve to shut off, retaining the pressure within the balloon indefinitely.
The prior art describes and claims a device such a one-way valve in Zeyra, U.S. Pat. No. 4,167,204. Referring now to FIGS. 5A and 5B a basic valve in accordance with said patent is shown. The head 109 of this prior art device contains the radial flange 109 F used for the same purpose as in the present patent. The check-valve effect is accomplished by means of the circular resilient disc 109 A. The gas is introduced by means of the filler element 110 which is inserted into the head 109 , creating pressure which forces the circular resilient disk 109 A outward against the guides 109 F.
In the present invention a check valve mechanism may be inserted into the body of the apparatus in order to effect the same end. Because such check valves are well known in the art, and because they are not part of the present invention, they will not be further described here.
A variation of the prior art filler of FIGS. 5A and 5B is shown in FIGS. 6A and 6B . A seen therein, a magnet 122 is mounted atop the lower cage fingers 109 H, and is restrained in place by upper cage fingers 120 . In this embodiment the magnet does not affect the operation of the check valve in the head, but provides a means for securely retaining the light-emitting assembly.
When using the filler-type device which also illuminates the inside of the balloon, the device is first inserted into the balloon, and then filled with the helium after insertion. Such a variation has the advantage of minimizing the amount of helium lost when the balloon is first filled and then the device is inserted afterwards.
In all of these embodiments the lighting element itself may be of various types. The preferring lighting element is a light-emitting diode (hereinafter “LED”) because of the availability of many different types of LEDs, available at very low prices, and further because of the extremely high efficiency and low power drain on the battery caused by the LED. Among the variations commercially available are LEDs which blink, which change color, and combinations of these two effects.
In addition to the magnetic mounting embodiment, many different approaches to mounting of the LED are proposed herein as further embodiments. Referring first to FIG. 4A , the assembly holding the light-emitting element 13 is restrained by barbed fingers 25 . The embodiment shown in this figure contains a self-contained light-emitting element having its own battery. It is clear that embodiments in which the battery and LED are separate units may also be used.
In FIG. 4B , a retaining ring 20 is force-fit over a mating enclosure 21 which contains the light-emitting element and battery. In a variation of the embodiment of FIG. 4B a screw-on retaining ring mates with mating threads on the enclosure 21 .
Alternative versions are proposed herein for the switching of the light element on and off. In the preferred embodiment depicted in FIG. 1A the user must rotate the upper housing 12 relative to the lower housing 11 , as previously stated.
In another alternative embodiment, the filling of the balloon with helium is used to switch the light element on. Referring first to FIG. 4C , this embodiment contains a battery 22 which is in permanent electrical contact with positive terminal of the LED assembly 13 . Ground connection is made by metallic element 23 , which is configured to keep the helium from passing into the balloon. Helium enters the balloon only through the port 24 . In FIG. 4C helium has not yet been inserted into the balloon: element 23 blocks the helium from entering the balloon except through port 24 . As the helium is first introduced contact element 23 blocks port 24 . At this stage the helium will force contact element 23 upwards until contact is made with the negative electrode of the battery, thereby completing the electrical circuit and causing the LED to illuminate, as shown in FIG. 4D . The teeth on mating enclosure 21 , contact element arms 26 , and light-element arms 27 form a ratchet mechanism, so that the contact element will stay in the position of FIG. 4D once the balloon is filled with helium, which is facilitated as the contact element rises to clear port 24 , allowing the gas into the balloon through this route.
Alternate embodiments of the illuminating device are shown in FIGS. 7A-C . As seen in FIG. 7A , upper and lower flanges 212 , 214 are spaced from one another by legs 216 . The upper flange 212 includes circuitry 218 , batteries 220 , and one or more LEDs 222 for illuminating the balloon B. The upper flange 212 can be formed as a circuit board (IC board) with the batteries 220 and LED(s) 222 mounted directly thereto, or the circuitry 218 (board), batteries 220 and LED(s) 222 can be mounted to a separate flange element (not shown). In a present embodiment, the flange 212 is formed as the board and three legs 216 mount the board 212 to the device 210 . A present embodiment of the device 210 includes three (3) LEDs 222 , however, it will be appreciated that any number of LEDs can be mounted to the device 210 .
The lower flange 214 provides a seal between the device 210 and the neck N of the balloon B, at the periphery 230 of the flange 214 . The legs 216 extend upwardly from the lower flange 214 to support the upper flange 212 (or board). In a present embodiment, the device 210 is formed with upwardly extending gussets 224 formed radially on the upper surface 226 of the lower flange 214 to provide additional support (e.g., stiffness) for the flange 214 .
A fill stem 228 extends downwardly (relative to the legs 216 ) from the lower flange 214 inside of the periphery 230 of the flange 214 . In a present embodiment, the stem 228 is concentrically disposed with the flange 214 . The fill stem 228 is a hollow tubular element. A one-way or check valve 232 is positioned in flow communication with the fill stem 228 . The valve 232 permits the one-way flow of gas from a source (such as tank or fill nipple) into the balloon B. In a present device 210 , the top or end 234 of the stem 228 is closed such as by a plug 236 , and an opening 238 is formed in a side wall 240 of the stem 228 , near the end 234 , below the plug 236 . The valve 232 is formed as a flexible sleeve 242 that is fitted over the upper end 234 of the stem 228 , covering the opening 238 . In a present embodiment, the opening 238 is formed near the stem end 234 , and the sleeve 242 is sufficiently thick and extends only slightly beyond the stem opening 238 . As pressurized gas is introduced into the stem 228 , the gas pressure overcomes over the force of the resilient sleeve, and the sleeve slightly deforms (opens outwardly) to allow the gas to “escape” from the opening 238 , past the edge 244 of the sleeve 242 , and into the balloon B. When the inlet (feed) pressure of the introduced gas drops off (e.g., removing the inflator from the fill nipple), the resilience of the sleeve 242 closes the sleeve 242 over the opening 238 to seal the inflator 210 . The sleeve 242 is fitted sufficiently tightly to the stem 228 so that even a high fill pressure and/or rate will not dislodge the sleeve 242 from the stem 228 . Rather, the sleeve 242 will be forced outwardly at about the opening 238 to allow the gas to move from the high pressure region (inside the stem 228 ) to the lower pressure region (inside the balloon B). In a present embodiment, the sleeve 242 has a thickened ring portion 246 , at the bottom of the sleeve 242 to further assure that the sleeve 242 remains on stem 228 as the balloon B is filled.
Radial gussets 248 can also be formed extending downwardly from the lower surface 250 of the lower flange 214 to provide additional support (e.g., stiffness) for the flange 214 .
As set forth above, one of the drawbacks with known inflators is that the switch to illuminate the lights (LEDs) is located on the upper flange, in the interior of the balloon. While this has made fabrication of the inflators easier, because the balloons are translucent (at best) it requires that a user poke his or her finger around the balloon to locate and activate the switch. Hunting for the switch is even more exaggerated given that the circuitry may be such that different operating modes (e.g., flashing, pulsating, steady on) may be achieved by multiple pressings of the switch.
The present illumination device 210 overcomes all of these problems by locating the switch 252 outside of the balloon B or outside of the pressurized region. In one embodiment, the switch 252 is located on the lower surface 250 of the lower flange 214 . An opening 254 in the lower flange 214 accommodates the electrical connectors (wires) 256 that extend between the switch 252 and the circuitry 218 , circuit board, batteries 220 or other component to which the connectors 256 are terminated. The opening 254 can be formed having a taper 258 , and an air-tight filler 260 is applied to the opening 254 around the connectors 256 . The filler 260 can be an adhesive, a liquefied polymer, hot-melt (adhesive), a mechanical plug or the like, and is applied after placement or penetration to the connectors 256 to assure integrity of the pressure boundary.
The switch 252 can be affixed to the lower flange 214 in any of a number of ways. For example, the switch 252 can be glued/adhered to the flange 214 , or, alternately, the switch 252 can have mounting posts 262 that extend from the base of the switch 252 through mount openings 264 in the lower flange 214 . The posts 262 can then be glued/adhered, or melted, to secure the switch 252 to the flange 214 . The post openings can also be sealed with an adhesive 260 or the like to prevent the escape of gas from the balloon.
The electrical connectors 256 extend from the switch 252 , through the opening 254 , to the circuitry 218 or other termination location. In a present embodiment, the connectors 256 extend through the space 266 between the flanges 212 , 214 . The connectors 256 can be fitted in one jacket 268 , and/or tied to one of the legs 216 , as by a wire tie 270 , a clip or the like to maintain the connectors 256 restrained and protected. Alternately, as seen in FIG. 7B , one of the legs 316 a can be formed as a hollow tube or conduit and the connectors 356 can be passed through the tube 316 a to restrain and protect the connectors 356 .
Alternately still, the illuminator 410 can be configured with the switch 452 mounted on the stem 428 , below the lower flange 414 . An opening 454 in the lower flange 414 accommodates the connectors 456 which extend to the circuitry 481 (or board 412 ). The switch 452 can be mounted to the stem 428 by an adhesive, such as a hot melt adhesive. Flanges 472 can be formed on or mounted to the stem 428 to support and secure the switch 452 . The opening 454 in the flange 414 can be sealed with an air-tight filler 460 applied to the opening 454 around the connectors 456 . The filler 460 can be an adhesive, a liquefied polymer, hot-melt (adhesive), a mechanical plug or the like.
All patents referred to herein, are hereby incorporated herein by reference, whether or not specifically done so within the text of this disclosure.
In the present disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular.
From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. | An illuminated inflator for inserting into the neck of a balloon includes a gas-tight flange having a periphery, a center, and upper and lower surfaces. A filler tube has upper and lower ends and extends through the flange, with the lower end of the filler tube extending below the lower surface the flange and the upper end of the filler tube extending above the upper surface of the flange. A one-way valve is in flow communication with the filler tube. A light assembly includes a power source and at least one light element electrically connected to the power source. The light assembly is operably mounted to the flange at the upper surface thereof. A switch is operably connected to the power source and the at least one light element for providing power to and isolating power from the at least one light element. The inflator is inserted into the balloon with the flange in the neck of the balloon defining a pressure region boundary. The bottom of the filler tube extends outside of the pressure region boundary for filling the balloon with a gas, such that the one-way valve prevents gas from escaping from the pressure region boundary through the filler tube. The switch is mounted to the inflator outside of the pressure region boundary to allow actuation/access to the switch without access to the pressure boundary and without contacting the balloon. | Summarize the key points of the given document. | [
"CROSS-REFERENCE TO RELATED APPLICATION DATA This application is a continuation-in-part of U.S. patent application Ser.",
"No. 12/032,876, filed Feb. 18, 2008, which is a continuation of U.S. patent application Ser.",
"No. 10/904,486, filed Nov. 12, 2004, now U.S. Pat. No. 7,344,267.",
"BACKGROUND OF THE INVENTION The present invention relates to illuminated toy balloons.",
"More particularly, the present invention relates to improved switch arrangements for illuminated balloon inflators.",
"The use of lights in association with balloons is well known.",
"Examples include U.S. Pat. Nos. 6,390,651 and 5,215,492.",
"Also well known is the use of chemiluminescent materials or light sticks that produce light by chemical reaction which may be inserted into balloons.",
"The present invention is an improvement over the known illuminated balloons in which an inexpensive, self-powered apparatus is inserted into the neck of a balloon, which contains a small, energy-efficient light source powered by a battery, and which includes a switch in the interior of the balloon to turn the light on and off.",
"While such illuminated balloons are known and function well, actuation of the switch can be difficult when it is located within the interior of the balloon.",
"Accordingly, there is a need for an illuminated balloon inflator in which the illuminated inflator apparatus is inserted in the balloon, the balloon then filled with a gas such as helium or air, and the light is easily switched on or off as desired.",
"SUMMARY OF THE INVENTION An illuminated inflator for inserting into the neck of a balloon includes a gas-tight flange having a periphery, a center, and upper and lower surfaces.",
"A filler tube has upper and lower ends and extends through the flange, with the lower end of the filler tube extending below the lower surface the flange and the upper end of the filler tube extending above the upper surface of the flange.",
"A one-way valve is in flow communication with the filler tube.",
"A light assembly includes a power source and at least one light element electrically connected to the power source.",
"The light assembly is operably mounted to the flange at the upper surface thereof.",
"A switch is operably connected to the power source and the at least one light element for providing power to and isolating power from the at least one light element.",
"The inflator is inserted into the balloon with the flange in the neck of the balloon defining a pressure region boundary.",
"The bottom of the filler tube extends outside of the pressure region boundary for filling the balloon with a gas, such that the one-way valve prevents gas from escaping from the pressure region boundary through the filler tube.",
"The switch is mounted to the inflator outside of the pressure region boundary to allow actuation/access to the switch without access to the pressure boundary and without contacting the balloon.",
"The inflator includes an electrical connector extending between the switch and light assembly.",
"The light assembly is mounted to and spaced from the gas-tight flange.",
"In a present embodiment, three legs extend between the gas-tight flange and the light assembly to elevate the light assembly into the balloon.",
"A present light element is an LED, preferably multiple (three) LEDs.",
"Circuitry is used to provide steady illumination, blinking illumination and flashing (e.g., a variety of illumination operating modes) of the LEDs.",
"The switch, which is external to the pressure boundary, can be mounted to the filler tube or to a lower surface of the flange to allow access to the switch without access to the pressure boundary and without contacting the balloon.",
"An opening in the lower flange accommodates the connectors (wires) and is sealed after placement/penetration of the connectors to assure the integrity of the pressure boundary.",
"These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.",
"BRIEF DESCRIPTION OF DRAWINGS The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein: FIG. 1 depicts a perspective view of a balloon containing the apparatus for illuminating the balloon interior.",
"FIG. 1A depicts a detail perspective view derived from FIG. 1 , showing the apparatus in greater detail.",
"FIG. 2A depicts a light element assembly containing a battery.",
"FIG. 2B depicts a perspective view of an embodiment of the apparatus using magnetic means to affix the light element to the plug.",
"FIG. 3 depicts a perspective view of the embodiment of FIG. 2 b , in which the light element assembly is magnetically affixed to the magnet.",
"FIG. 4A depicts an embodiment of the present invention in which the light element is affixed by means of barbs.",
"FIG. 4B depicts an embodiment of the present invention in which the light element is affixed by means of restraint fingers.",
"FIG. 4C depicts an embodiment in which the pressure of gas in the balloon switches on and off the lighting element, in the “off”",
"position.",
"FIG. 4D depicts an embodiment in which the pressure of gas in the balloon switches on and off the lighting element, in the “on”",
"position.",
"FIG. 5A depicts a prior-art balloon inflation device in cross section elevation view.",
"FIG. 5B depicts a prior-art balloon inflation device in top plan view.",
"FIG. 6A depicts an embodiment of a lighted balloon inflation device in cross section elevation view.",
"FIG. 6B depicts the embodiment of FIG. 6A in top plan view.",
"FIGS. 7A-7C illustrates alternate embodiments of the illuminated inflator device.",
"DETAILED DESCRIPTION OF THE INVENTION While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated.",
"It should be further understood that the title of this section of this specification, namely, “Detailed Description Of The Invention”, relates to a requirement of the United States Patent Office, and does not imply, nor should be inferred to limit the subject matter disclosed herein.",
"Referring to FIG. 1 , the present device 16 is inserted into the neck of a balloon, with a cord 3 attached to the device restraining the balloon.",
"The balloon is obviously filled with a gas, which may be air, helium, or similarly inert gasses, in the case of balloons used as toys, on account of safety concerns.",
"In other applications, where sufficient safeguards are taken, the gas need not be inert.",
"Referring now to FIG. 1A , the details of this device are revealed.",
"The device, in the form of a plug, contains a cylindrical body 3 which has an integrally formed radially extending flange 7 which retains the device within the balloon.",
"When the device is inserted into the neck 14 of the balloon, the flange 7 causes the neck to provide a gas-tight seal just above the neck ring 15 at the lower end of the neck, which provides stability for the balloon with the device inserted.",
"Still referring to FIG. 1A , a light-emitting assembly is shown disposed above the flange 7 .",
"The assembly is made up of the light emitting surface 13 , which is rigidly affixed to a screw-on cap 12 , which attaches to the lower assembly housing 11 .",
"A battery which powers the light-emitting assembly is contained within the lower housing and screw-on cap.",
"The user may turn the light on and off by screwing the cap down, and conversely screwing the cap in the opposite direction, relieving pressure and disconnecting power to the light element.",
"In the embodiment shown in FIG. 1A the light-emitting assembly is restrained in place by guides 8 .",
"Also contained in this embodiment is a magnet, not shown in this view, which is disposed below the base of the light-emitting assembly.",
"The use of the magnet in this embodiment may be further understood by referring next to FIGS. 2A , 2 B, and 3 .",
"FIGS. 2A and 2B depict the light-emitting assembly separated from the rest of the device.",
"The battery 12 , is clearly displayed in this figure, disposed entirely within the guides 8 , and concentrically disposed directly upon the flange 7 .",
"FIG. 3 shows the two elements combined to form the device prior to insertion into the balloon.",
"Still referring to these figures, the light-emitting assembly is mounted on the flange between the guides 8 , and restrained in place by the magnet 10 , which attracts the steel body of the light-emitting assembly 9 .",
"The body 4 of the device is in the form of a tube, or cylinder, which is hollow, containing a cylindrical chamber 5 and ending in a tab 6 , which provides a hole to which a cord may be attached.",
"In order to use the device, the balloon may first be filled, typically with helium, so that the balloon floats in the air.",
"In one embodiment the balloon is first filled with helium by means well known in the prior art, and which are not a part of this invention.",
"The user pinches off the neck to retain the helium within the balloon, and then quickly inserts the device into the neck of the balloon.",
"Once the insertion has been accomplished, the flange 7 provides a seal so that the helium will not escape from the balloon, except at a very, very slow rate.",
"In another variation of this invention, the device may contain a one-way valve, or check valve, permitting the helium to be inserted through the cylindrical chamber 5 , but not allowing the helium to escape back through the chamber.",
"In this embodiment the valve is located in the body of the device.",
"Ports (not shown) are provided between the valve and the head of the device to allow the helium to enter the balloon, but not escape.",
"In this embodiment the device is first inserted into the balloon neck, as shown in FIG. 1 , before filling.",
"The helium gas is then pumped in through the cylindrical channel 5 of the body 4 , which allows the balloon to fill, until the gas is shut off, relieving the pressure in the channel, and causing the check valve to shut off, retaining the pressure within the balloon indefinitely.",
"The prior art describes and claims a device such a one-way valve in Zeyra, U.S. Pat. No. 4,167,204.",
"Referring now to FIGS. 5A and 5B a basic valve in accordance with said patent is shown.",
"The head 109 of this prior art device contains the radial flange 109 F used for the same purpose as in the present patent.",
"The check-valve effect is accomplished by means of the circular resilient disc 109 A. The gas is introduced by means of the filler element 110 which is inserted into the head 109 , creating pressure which forces the circular resilient disk 109 A outward against the guides 109 F. In the present invention a check valve mechanism may be inserted into the body of the apparatus in order to effect the same end.",
"Because such check valves are well known in the art, and because they are not part of the present invention, they will not be further described here.",
"A variation of the prior art filler of FIGS. 5A and 5B is shown in FIGS. 6A and 6B .",
"A seen therein, a magnet 122 is mounted atop the lower cage fingers 109 H, and is restrained in place by upper cage fingers 120 .",
"In this embodiment the magnet does not affect the operation of the check valve in the head, but provides a means for securely retaining the light-emitting assembly.",
"When using the filler-type device which also illuminates the inside of the balloon, the device is first inserted into the balloon, and then filled with the helium after insertion.",
"Such a variation has the advantage of minimizing the amount of helium lost when the balloon is first filled and then the device is inserted afterwards.",
"In all of these embodiments the lighting element itself may be of various types.",
"The preferring lighting element is a light-emitting diode (hereinafter “LED”) because of the availability of many different types of LEDs, available at very low prices, and further because of the extremely high efficiency and low power drain on the battery caused by the LED.",
"Among the variations commercially available are LEDs which blink, which change color, and combinations of these two effects.",
"In addition to the magnetic mounting embodiment, many different approaches to mounting of the LED are proposed herein as further embodiments.",
"Referring first to FIG. 4A , the assembly holding the light-emitting element 13 is restrained by barbed fingers 25 .",
"The embodiment shown in this figure contains a self-contained light-emitting element having its own battery.",
"It is clear that embodiments in which the battery and LED are separate units may also be used.",
"In FIG. 4B , a retaining ring 20 is force-fit over a mating enclosure 21 which contains the light-emitting element and battery.",
"In a variation of the embodiment of FIG. 4B a screw-on retaining ring mates with mating threads on the enclosure 21 .",
"Alternative versions are proposed herein for the switching of the light element on and off.",
"In the preferred embodiment depicted in FIG. 1A the user must rotate the upper housing 12 relative to the lower housing 11 , as previously stated.",
"In another alternative embodiment, the filling of the balloon with helium is used to switch the light element on.",
"Referring first to FIG. 4C , this embodiment contains a battery 22 which is in permanent electrical contact with positive terminal of the LED assembly 13 .",
"Ground connection is made by metallic element 23 , which is configured to keep the helium from passing into the balloon.",
"Helium enters the balloon only through the port 24 .",
"In FIG. 4C helium has not yet been inserted into the balloon: element 23 blocks the helium from entering the balloon except through port 24 .",
"As the helium is first introduced contact element 23 blocks port 24 .",
"At this stage the helium will force contact element 23 upwards until contact is made with the negative electrode of the battery, thereby completing the electrical circuit and causing the LED to illuminate, as shown in FIG. 4D .",
"The teeth on mating enclosure 21 , contact element arms 26 , and light-element arms 27 form a ratchet mechanism, so that the contact element will stay in the position of FIG. 4D once the balloon is filled with helium, which is facilitated as the contact element rises to clear port 24 , allowing the gas into the balloon through this route.",
"Alternate embodiments of the illuminating device are shown in FIGS. 7A-C .",
"As seen in FIG. 7A , upper and lower flanges 212 , 214 are spaced from one another by legs 216 .",
"The upper flange 212 includes circuitry 218 , batteries 220 , and one or more LEDs 222 for illuminating the balloon B. The upper flange 212 can be formed as a circuit board (IC board) with the batteries 220 and LED(s) 222 mounted directly thereto, or the circuitry 218 (board), batteries 220 and LED(s) 222 can be mounted to a separate flange element (not shown).",
"In a present embodiment, the flange 212 is formed as the board and three legs 216 mount the board 212 to the device 210 .",
"A present embodiment of the device 210 includes three (3) LEDs 222 , however, it will be appreciated that any number of LEDs can be mounted to the device 210 .",
"The lower flange 214 provides a seal between the device 210 and the neck N of the balloon B, at the periphery 230 of the flange 214 .",
"The legs 216 extend upwardly from the lower flange 214 to support the upper flange 212 (or board).",
"In a present embodiment, the device 210 is formed with upwardly extending gussets 224 formed radially on the upper surface 226 of the lower flange 214 to provide additional support (e.g., stiffness) for the flange 214 .",
"A fill stem 228 extends downwardly (relative to the legs 216 ) from the lower flange 214 inside of the periphery 230 of the flange 214 .",
"In a present embodiment, the stem 228 is concentrically disposed with the flange 214 .",
"The fill stem 228 is a hollow tubular element.",
"A one-way or check valve 232 is positioned in flow communication with the fill stem 228 .",
"The valve 232 permits the one-way flow of gas from a source (such as tank or fill nipple) into the balloon B. In a present device 210 , the top or end 234 of the stem 228 is closed such as by a plug 236 , and an opening 238 is formed in a side wall 240 of the stem 228 , near the end 234 , below the plug 236 .",
"The valve 232 is formed as a flexible sleeve 242 that is fitted over the upper end 234 of the stem 228 , covering the opening 238 .",
"In a present embodiment, the opening 238 is formed near the stem end 234 , and the sleeve 242 is sufficiently thick and extends only slightly beyond the stem opening 238 .",
"As pressurized gas is introduced into the stem 228 , the gas pressure overcomes over the force of the resilient sleeve, and the sleeve slightly deforms (opens outwardly) to allow the gas to “escape”",
"from the opening 238 , past the edge 244 of the sleeve 242 , and into the balloon B. When the inlet (feed) pressure of the introduced gas drops off (e.g., removing the inflator from the fill nipple), the resilience of the sleeve 242 closes the sleeve 242 over the opening 238 to seal the inflator 210 .",
"The sleeve 242 is fitted sufficiently tightly to the stem 228 so that even a high fill pressure and/or rate will not dislodge the sleeve 242 from the stem 228 .",
"Rather, the sleeve 242 will be forced outwardly at about the opening 238 to allow the gas to move from the high pressure region (inside the stem 228 ) to the lower pressure region (inside the balloon B).",
"In a present embodiment, the sleeve 242 has a thickened ring portion 246 , at the bottom of the sleeve 242 to further assure that the sleeve 242 remains on stem 228 as the balloon B is filled.",
"Radial gussets 248 can also be formed extending downwardly from the lower surface 250 of the lower flange 214 to provide additional support (e.g., stiffness) for the flange 214 .",
"As set forth above, one of the drawbacks with known inflators is that the switch to illuminate the lights (LEDs) is located on the upper flange, in the interior of the balloon.",
"While this has made fabrication of the inflators easier, because the balloons are translucent (at best) it requires that a user poke his or her finger around the balloon to locate and activate the switch.",
"Hunting for the switch is even more exaggerated given that the circuitry may be such that different operating modes (e.g., flashing, pulsating, steady on) may be achieved by multiple pressings of the switch.",
"The present illumination device 210 overcomes all of these problems by locating the switch 252 outside of the balloon B or outside of the pressurized region.",
"In one embodiment, the switch 252 is located on the lower surface 250 of the lower flange 214 .",
"An opening 254 in the lower flange 214 accommodates the electrical connectors (wires) 256 that extend between the switch 252 and the circuitry 218 , circuit board, batteries 220 or other component to which the connectors 256 are terminated.",
"The opening 254 can be formed having a taper 258 , and an air-tight filler 260 is applied to the opening 254 around the connectors 256 .",
"The filler 260 can be an adhesive, a liquefied polymer, hot-melt (adhesive), a mechanical plug or the like, and is applied after placement or penetration to the connectors 256 to assure integrity of the pressure boundary.",
"The switch 252 can be affixed to the lower flange 214 in any of a number of ways.",
"For example, the switch 252 can be glued/adhered to the flange 214 , or, alternately, the switch 252 can have mounting posts 262 that extend from the base of the switch 252 through mount openings 264 in the lower flange 214 .",
"The posts 262 can then be glued/adhered, or melted, to secure the switch 252 to the flange 214 .",
"The post openings can also be sealed with an adhesive 260 or the like to prevent the escape of gas from the balloon.",
"The electrical connectors 256 extend from the switch 252 , through the opening 254 , to the circuitry 218 or other termination location.",
"In a present embodiment, the connectors 256 extend through the space 266 between the flanges 212 , 214 .",
"The connectors 256 can be fitted in one jacket 268 , and/or tied to one of the legs 216 , as by a wire tie 270 , a clip or the like to maintain the connectors 256 restrained and protected.",
"Alternately, as seen in FIG. 7B , one of the legs 316 a can be formed as a hollow tube or conduit and the connectors 356 can be passed through the tube 316 a to restrain and protect the connectors 356 .",
"Alternately still, the illuminator 410 can be configured with the switch 452 mounted on the stem 428 , below the lower flange 414 .",
"An opening 454 in the lower flange 414 accommodates the connectors 456 which extend to the circuitry 481 (or board 412 ).",
"The switch 452 can be mounted to the stem 428 by an adhesive, such as a hot melt adhesive.",
"Flanges 472 can be formed on or mounted to the stem 428 to support and secure the switch 452 .",
"The opening 454 in the flange 414 can be sealed with an air-tight filler 460 applied to the opening 454 around the connectors 456 .",
"The filler 460 can be an adhesive, a liquefied polymer, hot-melt (adhesive), a mechanical plug or the like.",
"All patents referred to herein, are hereby incorporated herein by reference, whether or not specifically done so within the text of this disclosure.",
"In the present disclosure, the words “a”",
"or “an”",
"are to be taken to include both the singular and the plural.",
"Conversely, any reference to plural items shall, where appropriate, include the singular.",
"From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention.",
"It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred."
] |
BACKGROUND OF THE INVENTION
1. field of The Invention
The present invention relates to moving target indicator radar systems, and more particularly to MTI radar systems employing two-pulse short interval techniques.
2. Description of the Prior Art
The patent, textbook and periodical literature describes a wide assortment of MTI radar systems. Fundamentally, MTI radar systems operate by examining signal returns resulting from successive transmitted pulses. Some type of cancellation, applicable to fixed returned signals corresponding to non-moving targets, or some type of filtering is employed to reject signals corresponding to non-moving targets. In the broadest sense, filtering may be said to include a wide variety of discriminatory devices ranging from frequency-chirp matched filters, Doppler component filters, and long period storage devices as used in some types of MTI systems.
A review of the prior art in respect to MTI radar may be conducted by examination and study of Chapter 17 of the text entitled "Radar Handbook" by Merrill Skolnik, a McGraw-Hill book (1970). That reference provides a bibliography of additional references and will serve to acquaint the reader not only with the current state of the MTI art, but also to apprise him of the problems confronted by the designer in that particular art.
Since the present invention makes use of the concepts of transmitted pulse "chirp" and receiving system pulse compression, Paragraph 17.15 of the aforementioned reference is of particular background interest. The reader is also directed to the textbook "Modern Radar Analysis, Evaluation, and System Design" by Raymond S. Berkowitz, a John Wiley and Sons book (third edition, August, 1967). In that particular reference book, the whole of Chapter 2 of Part IV is devoted to the subject of linear f-m pulse compression, which is useful background information in understanding the present invention.
Among the design problems encountered in the MTI systems are the problem of blind speed, antenna scan modulation and clutter fluctuation effects. Super-clutter visibility for targets moving in distributed clutter is also a problem area in which prior art systems have been deficient. The manner in which the present invention solves or eliminates certain significant problems encountered in the prior art will be understood as this description proceeds.
SUMMARY
In accordance with the start of the art in MTI radar systems, it may be said to have been the general object of the present invention to develop an MTI system having a high first blind speed, good super clutter visibility for targets moving in distributed clutter and also good sub-clutter visibility for targets moving in joint clutter, while preserving or providing good CFAR (constant false alarm rate) action and relatively high range resolution for a given long-range detectability. The device is relatively insensitive to antenna scan modulation and clutter fluctuation effects. The technique of the present invention is based on the use of a two-pulse coherent MTI system to discriminate between moving and stationary targets. As shown and described hereinafter, the time interval between the two pulses of the transmitted format is zero, although the system does not depend on that particular choice for operability. The use of a short or zero interval between transmitted pulses overcomes the detrimental effects of antenna scan modulation, clutter fluctuation and slow radar platform motion which normally limit the performance of long range coherent MTI systems. In addition, it will be realized that the very short MTI interval thereby provided is tantamount to the use of an extremely high pulse repetition frequency in a prior art MTI radar system, and the result is therefore a very high first blind speed.
It will be realized that the use of a short MTI interval introduces the problem of amgibuous range returns, a fact which has severely limited the use of two-pulse short interval MTI systems in long range radars heretofore. The present technique uses a transmission with unique coding of each of the two pulses to resolve the range ambiguity in a manner which will be apparent as the description proceeds.
The first half of the transmitted pulse is chirped over a frequency band of Δ F in a positive direction while the second half of the pulse is chirped in a negative direction. The selection of a positive chirp slope in the first half and negative in the second half will be realized to be arbitrary, however, it being possible to instrument the system oppositely with appropriate modification of the compression filtering format.
The two chirp slopes must be generated coherently about the same center frequency and the two slopes must be carefully matched, however component and sub-system techniques for accomplishing these requirements are well known in the present day radar art.
The two signals or two halves of the transmitted pulse envolope may be thought of as comprising a single transmitted pulse, hence the term - "intra-pulse MTI".
After transmission, a normal ranging time of T R is provided which is commensurate with the radar maximum range. During each ranging interval, target signals from each half of the transmitted envolope are received and processed in the twochannel system of the receiving equipment. The upper channel has a pulse compresser matched to the positive chirp signal and the lower channel has a pulse compresser matched to the negative chirp signal. Pulse compression is accomplished in two successive stages separated by a limiter circuit in each channel. The system depends upon the unique instrumentation of the pulse compression function in order to effectively measure target motion from one-half of the transmitted pulse to the other half. The two receiving channels are time aligned by a deduction of a fixed delay from the earliest processed data equal to Δ T (half of the total transmitted pulse) and the outputs of the two channels are differenced vectorially. The result is cancellation of signals corresponding to non-moving targets and transmission through the differencer of signals which are moving and therefore do change physical position over the duration of thetotal transmitted pulse. The details of the pulse compression instrumentation will be described as this description proceeds.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a functional and structural block diagram of the transmitting and receiving system in accordance with the present invention.
FIG. 2 is a waveform timing diagram depicting the signal characteristics at various points in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In describing the structure and operation of the system according to the invention as depicted in FIG. 1, appropriate reference will be made from time to time to the waveforms of FIG. 2.
In FIG. 1, both transmitting and receiving systems are depicted in block form. The transmitting antenna 10 and receiving antenna 12 are to be understood to be any of the commonly used directive scanning antennas suitable for MTI system use. In fact, these transmitting and receiving antennas may be one antenna with a suitable duplexing system, as is well known in the radar arts. Reference to this and the details of the antenna scan drives, etc., which form no part of the present invention of themselves have been omitted from the drawings for the sake of simplicity and a concise description of the novel aspects of the instrumentation.
FIG. 1 illustrates the transmitter chirp function. Since the present system is an improved type of frequency modulated pulse and pulse compression system, it achieves the advantages accruing to such systems fundamentally. Among these advantages is the relatively high average power on target as a result of the relatively long transmitted pulse. A typical duration for the total transmitted pulse may be 100 microseconds, a figure that will be taken for the sake of the present description. This duration is composed of two pulse halves each of duration Δ T. Accordingly, the received pulse energy envelope at (b) of FIG. 2 is similarly 2 Δ T in duration. The depiction of the transmitted pulse of FIG. 2 ahead of the time-aligned receiver waveforms (b) through (j) is illustrative of the fact that a ranging interval exists between transmitted and received pulses, although the particular time relation compared to the 100 microsecond pulse duration figure is not necessarily scaler.
The embodiment of the present invention described involves signal processing in the IF domain. Accordingly, it will be understood that the waveforms (a) through (k) of FIG. 2 are representative of signal amplitudes as a function of time. The actual signals would be bi-polar IF signals, however, the FIG. 2 waveforms would be properly representative of IF signal amplitudes converted to video signals.
The frequency modulated pulse transmitter 11 includes a pulse repetition frequency generator as well as means for accurately and coherently generating positive and negative chirp slopes of the said transmitted pulse about the same center frequency. The instrumentation of the block 11 is readily accomplished by persons skilled in this art.
For the sake of relatively simple treatment of the receiving function, the waveforms of FIG. 2 and their description in relation to FIG. 1 is based on the point target assumption. Obviously return signal energy would be present throughout most or all of the ranging interval after each transmitted pulse in an environment containing the usual assortment of fixed and moving targets. The operation of the system, once understood in connection with the point target, however, will be appreciated in relation to the practical signal environment.
To go forward with the description in accordance with the foregoing, it will be noted that a signal envelope of 2 ΔT in duration and arbitrary power level P is received at antenna 12 from the said point target. A mixer 13 and local oscillator source 14 provide the usual and straightforward down-conversion to the IF domain. The power divider 15, which is not more than a straightforward well known Tee or power splitter device suitable for operation at the IF band, splits the received energy into two substantially equal inputs to the IF amplifiers 16 and 17. These IF amplifiers constitute the input devices to the two receiving channels of the device of the present invention. Based on the nature of the transmitted pulse frequency-versus-time function in accordance with FIG. 2(a), it follows that the pulse compression slope of the pulse compressor 18 should be + Δ F/T and that of pulse compressor 19 should be - Δ F/T. The output of pulse compressor 18 is depicted in FIG. 2 waveform (c) and the output of 19 is similarly depicted at waveform (d) of FIG. 2. Stated otherwise, it may be said that the upper channel has a pulse compressor (first stage) matched to the positive chirp signal and the lower channel has a similar pulse compressor matched to the negative chirp signal. Each channel will exhibit an output spectrum including a peaked signal and a "smeared" signal at the output of the first compressor stage. The upper channel will compress the signals from the first half of the pulse and will further disperse the signals from the second half of the pulse. Similarly, the lower channel will compress signals from the second half of the pulse and further disperse signals from the first half of the pulse. This phenomenon is identifiable in waveform (c) and (d) of FIG. 2, respectively, wherein the said peak signals are 30 and 33 and the "smeared" or further dispersed frequency spectra are observed at 31 and 32. The amplitude of the peaked signal is identified as DP which is the product of the compression ratio of the system and the arbitrary power P. The so-called "smeared" residue will be seen having a signal amplitude of half the arbitrary power P.
The upper and lower channel hard limiters 20 and 21, respectively, are adjusted to eliminate the peaked signals 30 and 33, resulting in the waveforms (e) and (f) of FIG. 2, respectively, which are then applied to the second pulse compressors 22 and 23, respectively. It will be noted that the slope of these second compressor stages is the reverse of that applied at the first pulse compressor stage in each of the channels. That is, the second upper pulse compressor 2 has a response slope equal to a - (Δ f/2Δ t) and the lower corresponding stage 23 exhibits a slope of + (Δ f/2Δ t). The larger denominator in the slope expression of these second stage compressors reflects the fact that the first pulse compressor stretched the signals by an additional Δ t in time. Hence, these second compressor stages are matched to a dispersion (Δ f/2Δt).
After the second pulse compressor stages, the dispersed signals will be peaked. Signals which had been peaked by the first compressor and subsequently limited, are dispersed by the second compressor, greatly reducing the amplitude of these ambiguous signals. The newly formed peak signals 35 and 36 and the corresponding further reduced ambiguous signal residue 34 and 37, will be seen in the corresponding output waveforms (g) and (h) of FIG. 2.
Before application to the differencing circuit 28, the waveform (g) of FIG. 2 present at 24 in FIG. 1 and the waveform (h) of FIG. 2 seen at 25 in FIG. 1 must be time-aligned. For this purpose, the fixed delay Δ t at 27 is introduced in series with the output of pulse compressor 23 in the said lower channel. The resultant signal 26 is then that represented at waveform (j) at FIG. 2. Straightforward differencing of the waveforem (g) against that of the waveform (j) of FIG. 2 is accomplished using known differencing techniques in the IF differencer 28. The waveform (k) of FIG. 2 depicts the ambiguity residue after differencing. In that particular case, no net signal resulting from the differencing of 35 and 38 is extant.
It will be noted that for point targets the said ambiguity residue is down by a factor of 4D 2 with respect to the main signal. Here again, it will be remembered that D is the compression ratio of the system, and is equal to the product of Δ t and Δ f. From this it can be shown that a system with a 20DB compression ratio will have an ambiguity residue 46DB below the channel output.
The advantages of a short interval MTI system in accordance with the present invention can be illustrated by considering, for example, a prior art S-Band system designed for 200 miles of coverage and having a 1° beamwidth in a scanning rate of 10 rpm or 60° per second. With an MTI comparison interval determined by the maximum unambiguous range of 200 statue miles, or 2,160 microseconds, the MTI performance would be limited by scan modulation to about 15 decibels with a single canceller or to about 21 decibels with a double canceller. Furthermore, such a prior art MTI system would exhibit a first blind speed of about 40 knots. The clutter attenuation on heavy wooden hills (with 20 mile per hour wind) would be limited to about 23 decibels by clutter fluctuation phenomena and to about 11 decibels on chaff and sea echo. Such numbers are typical of the type of MTI performance normally possible with prior art long range narrow beam radars when an unambiguous MTI interval is used.
It, in the same basic S-Band system, a 50 microsecond MTI interval as in the example of the present invention is employed, a first blind speed of 2000 knots would result. Furthermore, an antenna scan modulation limitation of about 50 decibels with a single canceller and clutter attenuation of 57 db on heavily wooden hills and 45 db on chaff and sea echo as limited by clutter fluctuation, could be obtained. A short MTI interval of 50 microseconds (measured from the middle of the first slope to the middle of the second slope in the transmitted pulse of the present system) also permits cancellation at IF with a high degree of stability.
An additional fact about the present system, which will suggest itself to those skilled in this art, is that the limiting process prior to final compression will inherently provide a CFAR (constantfalse-alarm-rate) action since it will tend to suppress distributed clutter or any other noise-like signal which is not compressed by the final pulse compressor. Thus, for moving targets flying in distributed clutter it can be said that it will at least provide superclutter visibility and will not report distributed clutter or incompressible signals.
The MTI performance on point targets is relatively insensitive to slow radar platform motion, such as ship movemet, pitch and roll, etc., because of the low response to the system to low velocities.
The intra-pulse MTI system of the invention could also be augmented by a conventional MTI system using long comparison intervals and the outputs of the two utilized selectively. The long comparison interval would have the advantage of higher sensitivity to slow moving targets (those with low radial velocity) and thus, could compliment the relatively poor visibility factor of the short interval MTI for slow moving targets.
From the foregoing, it will be realized however, that the performance of the present invention with relatively fast moving targets, is not subject to degradation.
Various modifications and variations of the present invention will suggest themselves to those skilled in this art. Accordingly, it is not intended that the present invention should be limited by the specific embodiment illustrated and by this description, these being regarded as typical and illustrative only. | A dual-pulse coherent MTI system having a time interval between pulses as short as zero. The pulses are "chirped" in opposite sense, the latter constituting a unique coding for eliminating range ambiguity problems. Video return signals are received and applied to two parallel channels each containing pulse compression and limiting circuits. The pulse compression circuits are matched uniquely to the positive chirp slope pulse in one channel and to the negative chirp slope pulse in the other channel. The channel corresponding to the earlier of the two pulses is subjected to a fixed delay of one pulse width before the outputs of the channels are differenced to produce a net MTI signal. This is a continuation of application Ser. No. 159,751, filed July 6, 1971, now abandoned. | Summarize the patent document, focusing on the invention's functionality and advantages. | [
"BACKGROUND OF THE INVENTION 1.",
"field of The Invention The present invention relates to moving target indicator radar systems, and more particularly to MTI radar systems employing two-pulse short interval techniques.",
"Description of the Prior Art The patent, textbook and periodical literature describes a wide assortment of MTI radar systems.",
"Fundamentally, MTI radar systems operate by examining signal returns resulting from successive transmitted pulses.",
"Some type of cancellation, applicable to fixed returned signals corresponding to non-moving targets, or some type of filtering is employed to reject signals corresponding to non-moving targets.",
"In the broadest sense, filtering may be said to include a wide variety of discriminatory devices ranging from frequency-chirp matched filters, Doppler component filters, and long period storage devices as used in some types of MTI systems.",
"A review of the prior art in respect to MTI radar may be conducted by examination and study of Chapter 17 of the text entitled "Radar Handbook"",
"by Merrill Skolnik, a McGraw-Hill book (1970).",
"That reference provides a bibliography of additional references and will serve to acquaint the reader not only with the current state of the MTI art, but also to apprise him of the problems confronted by the designer in that particular art.",
"Since the present invention makes use of the concepts of transmitted pulse "chirp"",
"and receiving system pulse compression, Paragraph 17.15 of the aforementioned reference is of particular background interest.",
"The reader is also directed to the textbook "Modern Radar Analysis, Evaluation, and System Design"",
"by Raymond S. Berkowitz, a John Wiley and Sons book (third edition, August, 1967).",
"In that particular reference book, the whole of Chapter 2 of Part IV is devoted to the subject of linear f-m pulse compression, which is useful background information in understanding the present invention.",
"Among the design problems encountered in the MTI systems are the problem of blind speed, antenna scan modulation and clutter fluctuation effects.",
"Super-clutter visibility for targets moving in distributed clutter is also a problem area in which prior art systems have been deficient.",
"The manner in which the present invention solves or eliminates certain significant problems encountered in the prior art will be understood as this description proceeds.",
"SUMMARY In accordance with the start of the art in MTI radar systems, it may be said to have been the general object of the present invention to develop an MTI system having a high first blind speed, good super clutter visibility for targets moving in distributed clutter and also good sub-clutter visibility for targets moving in joint clutter, while preserving or providing good CFAR (constant false alarm rate) action and relatively high range resolution for a given long-range detectability.",
"The device is relatively insensitive to antenna scan modulation and clutter fluctuation effects.",
"The technique of the present invention is based on the use of a two-pulse coherent MTI system to discriminate between moving and stationary targets.",
"As shown and described hereinafter, the time interval between the two pulses of the transmitted format is zero, although the system does not depend on that particular choice for operability.",
"The use of a short or zero interval between transmitted pulses overcomes the detrimental effects of antenna scan modulation, clutter fluctuation and slow radar platform motion which normally limit the performance of long range coherent MTI systems.",
"In addition, it will be realized that the very short MTI interval thereby provided is tantamount to the use of an extremely high pulse repetition frequency in a prior art MTI radar system, and the result is therefore a very high first blind speed.",
"It will be realized that the use of a short MTI interval introduces the problem of amgibuous range returns, a fact which has severely limited the use of two-pulse short interval MTI systems in long range radars heretofore.",
"The present technique uses a transmission with unique coding of each of the two pulses to resolve the range ambiguity in a manner which will be apparent as the description proceeds.",
"The first half of the transmitted pulse is chirped over a frequency band of Δ F in a positive direction while the second half of the pulse is chirped in a negative direction.",
"The selection of a positive chirp slope in the first half and negative in the second half will be realized to be arbitrary, however, it being possible to instrument the system oppositely with appropriate modification of the compression filtering format.",
"The two chirp slopes must be generated coherently about the same center frequency and the two slopes must be carefully matched, however component and sub-system techniques for accomplishing these requirements are well known in the present day radar art.",
"The two signals or two halves of the transmitted pulse envolope may be thought of as comprising a single transmitted pulse, hence the term - "intra-pulse MTI".",
"After transmission, a normal ranging time of T R is provided which is commensurate with the radar maximum range.",
"During each ranging interval, target signals from each half of the transmitted envolope are received and processed in the twochannel system of the receiving equipment.",
"The upper channel has a pulse compresser matched to the positive chirp signal and the lower channel has a pulse compresser matched to the negative chirp signal.",
"Pulse compression is accomplished in two successive stages separated by a limiter circuit in each channel.",
"The system depends upon the unique instrumentation of the pulse compression function in order to effectively measure target motion from one-half of the transmitted pulse to the other half.",
"The two receiving channels are time aligned by a deduction of a fixed delay from the earliest processed data equal to Δ T (half of the total transmitted pulse) and the outputs of the two channels are differenced vectorially.",
"The result is cancellation of signals corresponding to non-moving targets and transmission through the differencer of signals which are moving and therefore do change physical position over the duration of thetotal transmitted pulse.",
"The details of the pulse compression instrumentation will be described as this description proceeds.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a functional and structural block diagram of the transmitting and receiving system in accordance with the present invention.",
"FIG. 2 is a waveform timing diagram depicting the signal characteristics at various points in FIG. 1. DESCRIPTION OF THE PREFERRED EMBODIMENT In describing the structure and operation of the system according to the invention as depicted in FIG. 1, appropriate reference will be made from time to time to the waveforms of FIG. 2. In FIG. 1, both transmitting and receiving systems are depicted in block form.",
"The transmitting antenna 10 and receiving antenna 12 are to be understood to be any of the commonly used directive scanning antennas suitable for MTI system use.",
"In fact, these transmitting and receiving antennas may be one antenna with a suitable duplexing system, as is well known in the radar arts.",
"Reference to this and the details of the antenna scan drives, etc.",
", which form no part of the present invention of themselves have been omitted from the drawings for the sake of simplicity and a concise description of the novel aspects of the instrumentation.",
"FIG. 1 illustrates the transmitter chirp function.",
"Since the present system is an improved type of frequency modulated pulse and pulse compression system, it achieves the advantages accruing to such systems fundamentally.",
"Among these advantages is the relatively high average power on target as a result of the relatively long transmitted pulse.",
"A typical duration for the total transmitted pulse may be 100 microseconds, a figure that will be taken for the sake of the present description.",
"This duration is composed of two pulse halves each of duration Δ T. Accordingly, the received pulse energy envelope at (b) of FIG. 2 is similarly 2 Δ T in duration.",
"The depiction of the transmitted pulse of FIG. 2 ahead of the time-aligned receiver waveforms (b) through (j) is illustrative of the fact that a ranging interval exists between transmitted and received pulses, although the particular time relation compared to the 100 microsecond pulse duration figure is not necessarily scaler.",
"The embodiment of the present invention described involves signal processing in the IF domain.",
"Accordingly, it will be understood that the waveforms (a) through (k) of FIG. 2 are representative of signal amplitudes as a function of time.",
"The actual signals would be bi-polar IF signals, however, the FIG. 2 waveforms would be properly representative of IF signal amplitudes converted to video signals.",
"The frequency modulated pulse transmitter 11 includes a pulse repetition frequency generator as well as means for accurately and coherently generating positive and negative chirp slopes of the said transmitted pulse about the same center frequency.",
"The instrumentation of the block 11 is readily accomplished by persons skilled in this art.",
"For the sake of relatively simple treatment of the receiving function, the waveforms of FIG. 2 and their description in relation to FIG. 1 is based on the point target assumption.",
"Obviously return signal energy would be present throughout most or all of the ranging interval after each transmitted pulse in an environment containing the usual assortment of fixed and moving targets.",
"The operation of the system, once understood in connection with the point target, however, will be appreciated in relation to the practical signal environment.",
"To go forward with the description in accordance with the foregoing, it will be noted that a signal envelope of 2 ΔT in duration and arbitrary power level P is received at antenna 12 from the said point target.",
"A mixer 13 and local oscillator source 14 provide the usual and straightforward down-conversion to the IF domain.",
"The power divider 15, which is not more than a straightforward well known Tee or power splitter device suitable for operation at the IF band, splits the received energy into two substantially equal inputs to the IF amplifiers 16 and 17.",
"These IF amplifiers constitute the input devices to the two receiving channels of the device of the present invention.",
"Based on the nature of the transmitted pulse frequency-versus-time function in accordance with FIG. 2(a), it follows that the pulse compression slope of the pulse compressor 18 should be + Δ F/T and that of pulse compressor 19 should be - Δ F/T.",
"The output of pulse compressor 18 is depicted in FIG. 2 waveform (c) and the output of 19 is similarly depicted at waveform (d) of FIG. 2. Stated otherwise, it may be said that the upper channel has a pulse compressor (first stage) matched to the positive chirp signal and the lower channel has a similar pulse compressor matched to the negative chirp signal.",
"Each channel will exhibit an output spectrum including a peaked signal and a "smeared"",
"signal at the output of the first compressor stage.",
"The upper channel will compress the signals from the first half of the pulse and will further disperse the signals from the second half of the pulse.",
"Similarly, the lower channel will compress signals from the second half of the pulse and further disperse signals from the first half of the pulse.",
"This phenomenon is identifiable in waveform (c) and (d) of FIG. 2, respectively, wherein the said peak signals are 30 and 33 and the "smeared"",
"or further dispersed frequency spectra are observed at 31 and 32.",
"The amplitude of the peaked signal is identified as DP which is the product of the compression ratio of the system and the arbitrary power P. The so-called "smeared"",
"residue will be seen having a signal amplitude of half the arbitrary power P. The upper and lower channel hard limiters 20 and 21, respectively, are adjusted to eliminate the peaked signals 30 and 33, resulting in the waveforms (e) and (f) of FIG. 2, respectively, which are then applied to the second pulse compressors 22 and 23, respectively.",
"It will be noted that the slope of these second compressor stages is the reverse of that applied at the first pulse compressor stage in each of the channels.",
"That is, the second upper pulse compressor 2 has a response slope equal to a - (Δ f/2Δ t) and the lower corresponding stage 23 exhibits a slope of + (Δ f/2Δ t).",
"The larger denominator in the slope expression of these second stage compressors reflects the fact that the first pulse compressor stretched the signals by an additional Δ t in time.",
"Hence, these second compressor stages are matched to a dispersion (Δ f/2Δt).",
"After the second pulse compressor stages, the dispersed signals will be peaked.",
"Signals which had been peaked by the first compressor and subsequently limited, are dispersed by the second compressor, greatly reducing the amplitude of these ambiguous signals.",
"The newly formed peak signals 35 and 36 and the corresponding further reduced ambiguous signal residue 34 and 37, will be seen in the corresponding output waveforms (g) and (h) of FIG. 2. Before application to the differencing circuit 28, the waveform (g) of FIG. 2 present at 24 in FIG. 1 and the waveform (h) of FIG. 2 seen at 25 in FIG. 1 must be time-aligned.",
"For this purpose, the fixed delay Δ t at 27 is introduced in series with the output of pulse compressor 23 in the said lower channel.",
"The resultant signal 26 is then that represented at waveform (j) at FIG. 2. Straightforward differencing of the waveforem (g) against that of the waveform (j) of FIG. 2 is accomplished using known differencing techniques in the IF differencer 28.",
"The waveform (k) of FIG. 2 depicts the ambiguity residue after differencing.",
"In that particular case, no net signal resulting from the differencing of 35 and 38 is extant.",
"It will be noted that for point targets the said ambiguity residue is down by a factor of 4D 2 with respect to the main signal.",
"Here again, it will be remembered that D is the compression ratio of the system, and is equal to the product of Δ t and Δ f. From this it can be shown that a system with a 20DB compression ratio will have an ambiguity residue 46DB below the channel output.",
"The advantages of a short interval MTI system in accordance with the present invention can be illustrated by considering, for example, a prior art S-Band system designed for 200 miles of coverage and having a 1° beamwidth in a scanning rate of 10 rpm or 60° per second.",
"With an MTI comparison interval determined by the maximum unambiguous range of 200 statue miles, or 2,160 microseconds, the MTI performance would be limited by scan modulation to about 15 decibels with a single canceller or to about 21 decibels with a double canceller.",
"Furthermore, such a prior art MTI system would exhibit a first blind speed of about 40 knots.",
"The clutter attenuation on heavy wooden hills (with 20 mile per hour wind) would be limited to about 23 decibels by clutter fluctuation phenomena and to about 11 decibels on chaff and sea echo.",
"Such numbers are typical of the type of MTI performance normally possible with prior art long range narrow beam radars when an unambiguous MTI interval is used.",
"It, in the same basic S-Band system, a 50 microsecond MTI interval as in the example of the present invention is employed, a first blind speed of 2000 knots would result.",
"Furthermore, an antenna scan modulation limitation of about 50 decibels with a single canceller and clutter attenuation of 57 db on heavily wooden hills and 45 db on chaff and sea echo as limited by clutter fluctuation, could be obtained.",
"A short MTI interval of 50 microseconds (measured from the middle of the first slope to the middle of the second slope in the transmitted pulse of the present system) also permits cancellation at IF with a high degree of stability.",
"An additional fact about the present system, which will suggest itself to those skilled in this art, is that the limiting process prior to final compression will inherently provide a CFAR (constantfalse-alarm-rate) action since it will tend to suppress distributed clutter or any other noise-like signal which is not compressed by the final pulse compressor.",
"Thus, for moving targets flying in distributed clutter it can be said that it will at least provide superclutter visibility and will not report distributed clutter or incompressible signals.",
"The MTI performance on point targets is relatively insensitive to slow radar platform motion, such as ship movemet, pitch and roll, etc.",
", because of the low response to the system to low velocities.",
"The intra-pulse MTI system of the invention could also be augmented by a conventional MTI system using long comparison intervals and the outputs of the two utilized selectively.",
"The long comparison interval would have the advantage of higher sensitivity to slow moving targets (those with low radial velocity) and thus, could compliment the relatively poor visibility factor of the short interval MTI for slow moving targets.",
"From the foregoing, it will be realized however, that the performance of the present invention with relatively fast moving targets, is not subject to degradation.",
"Various modifications and variations of the present invention will suggest themselves to those skilled in this art.",
"Accordingly, it is not intended that the present invention should be limited by the specific embodiment illustrated and by this description, these being regarded as typical and illustrative only."
] |
This is a divisional of U.S. patent application Ser. No. 09/335,346, filed Jun. 17, 1999, abandoned, in the name of Toshiro Hiratsuka, Tomiya Sonoda, Shigeyuki Mikami and Kiyoshi Kanagawa, titled DIELECTRIC FILTER TRANSMISSION/RECEPTION SHARING DEVICE AND COMMUNICATION DEVICE, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a dielectric filter in which a resonator is formed on a dielectric plate, a transmission/reception sharing device and a communication device using the dielectric filter.
2. Description of the Related Art
A bandpass filter having a plurality of resonators in series has been used in a communication device.
To obtain large attenuation above and below a pass band, the so called “jump-coupling method” has been utilized. In accordance with the method, a pair of resonators are directly electromagnetically coupled to each other jumping over another resonator therebetween. By causing the jump-coupling, a notch or pole appears outside the pass band
On the other hand, a planar-circuit type dielectric filter is expected to be widely used in a wireless LAN, a portable visual telephone and a next generation satellite broadcasting system. These applications use sub-millimeter waves. This type of filter is described in Japanese Patent Application No. 9-103017. It should be noted that the Japanese application was not laid-open to the public at the time of filing Japanese Patent Application No. 10-171174 on which this case is based. Thus, the reference is provided as background information to show the state of the art only. The citation of the reference is not to be construed as an admission that it constitutes prior art.
The application No. JP-A-9-103017 discloses a dielectric filter in which an electrode is formed on each side of a dielectric plate to constitute a resonator at the prescribed position of the dielectric plate, a micro-strip line is formed on a substrate, and the micro-strip line is coupled with the dielectric resonator.
This dielectric filter is extremely advantageous, being compact in size, easy to manufacture, and capable of easily obtaining the desired characteristics.
The above-mentioned jump-coupling is also effective to secure the large attenuation on the high-frequency side or the low-frequency side of its pass band of the planar circuit type dielectric filter.
An example is illustrated in FIG. 19 and FIG. 20, where the above-mentioned filter device in which a part of the dielectric plate is used as the resonator and a structure for causing jump-coupling between the resonators is implemented. FIG. 19 is an assembly view in which electrodes 2 , 3 having electrode-free parts of the same shape opposite to each other across a dielectric plate are provided on each side of the dielectric plate 1 to constitute a third-order filter. Numerals 4 a, 4 b and 4 c denote electrode-free parts on the upper surface thereof. Numeral 6 denotes a substrate on which a microstrip line to be coupled with the resonator is formed, and a basic part of the dielectric filter is constituted by successively laminating a package 8 , the dielectric plate 1 , an electromagnetic wave absorption body 11 and a shield 12 comprising a metallic plate thereon. In order to cause a pole outside the pass band, a semi-rigid cable in which a coupling loop is formed on each end is provided on the shield 12 in order to cause jump-coupling between a first-stage resonator and a third-stage resonator as illustrated in the figures.
FIG. 20 illustrates a sectional view of the abovementioned dielectric filter. The filter device has a higher profile because of the diameter of the semi-rigid cable. Thus, a dead space may be produced when the filter device is installed in electronic equipment. Also, a separate semi-rigid cable is necessary, the assembly process requires machining and soldering to form the coupling loop, and the cost is increased as a whole. Further, because the position of an attenuation pole is largely changed depending on the direction, length, etc., of the coupling loop, it is relatively difficult to adjust the position of the cable to obtain a desired filter characteristic.
SUMMARY OF THE INVENTION
The present invention provides a dielectric filter in which the above-mentioned problems caused by using separate parts such as a semi-rigid cable are solved, and a transmission/reception sharing device and communication device using the dielectric filter.
In the present invention, an electrode having electrode-free parts opposite to each other, on opposite sides of a dielectric plate, is provided on each side of the dielectric plate, an area between the electrode electrode-free parts is a resonator, and a plurality of stages of resonators in which adjacent resonators are successively coupled with each other, are provided on the dielectric plate. A coupling line for polarization, which directly couples two resonators by respectively coupling the line with the two resonators which may be separated from each other by one or more other stages among a plurality of resonators, is provided on a substrate separated from the dielectric plate by a prescribed distance. In such a structure, the coupling line for polarization is provided on the substrate, and no parts such as the semi-rigid cable are projected outside, and the device is not increased in size.
In the present invention, a line for signal input/output to be coupled with prescribed resonators is provided on the substrate provided with the coupling line for causing a pole. This structure dispenses with a special substrate on which a coupling line for causing a pole is provided in addition to a substrate on which the line for signal input/output is provided.
The substrate provided with the coupling line is used as a shield cover by forming an electrode on approximately the whole surface opposite to a surface on which the coupling line for polarization is formed. The structure dispenses with a single shield cover, and also dispenses with a substrate exclusively used for forming the coupling line for polarization.
In the present invention, an electrode having openings of approximately same shape which are opposite to each other, on opposite sides of a dielectric plate, is provided on each side of the dielectric plate, an area between the openings is a resonator, and a plurality of stages of resonators in which adjacent resonators are successively coupled with each other, are provided on the dielectric plate. A coupling line for polarization, which directly couples two resonators, e.g., through a slot line, by respectively coupling the line with the two resonators which may be separated from each other by one or more other stages among a plurality of resonators, is provided on the substrate. Such a structure dispenses with a substrate for forming the coupling line for polarization, and simultaneous patterning is realized in forming resonators.
Also, in the present invention, a transmission/reception sharing device is constituted by providing either of the above-mentioned dielectric filters as a transmission filter, a reception filter, or both filters.
Further, in the present invention, a communication device is constituted by providing the dielectric filter in a high-frequency circuit part, or in a transmission/reception sharing device such as, for example, an antenna. Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an assembly view of a dielectric filter according to a first embodiment;
FIG. 2 is a top plan view of a substrate of the dielectric filter;
FIG. 3 is a characteristic graph of the dielectric filter;
FIG. 4 is an assembly view of a dielectric filter according to a second embodiment;
FIG. 5 is a top plan view of a substrate of the dielectric filter;
FIG. 6 is a characteristic graph of the dielectric filter;
FIG. 7 is an assembly view of a dielectric filter according to a third embodiment;
FIG. 8 is a bottom plan view of a cover of the dielectric filter;
FIG. 9 is a bottom plan view of a cover and a top plan view of a substrate of a dielectric filter according to a fourth embodiment;
FIG. 10 is a bottom plan view of a cover and a top plan view of a substrate of another dielectric filter according to the fourth embodiment;
FIG. 11 is a bottom plan view of a cover and a top plan view of a substrate of still another dielectric filter according to the fourth embodiment;
FIG. 12 is a characteristic graph of the dielectric filters illustrated in FIG. 9 through FIG. 11;
FIG. 13 is an assembly view of a dielectric filter according to a fifth embodiment;
FIG. 14 is a top plan view of a dielectric plate of the dielectric filter;
FIG. 15 is a top plan view of an substrate of a dielectric filter making use of the HE110 mode;
FIG. 16 is a top plan view of a dielectric plate of a dielectric filter where a coplanar line is a line for polarization;
FIG. 17 is a top plan view of an substrate of a transmission/reception sharing device;
FIG. 18 is a block diagram to illustrate the constitution of a communication device;
FIG. 19 is an assembly view of a conventional dielectric filter; and
FIG. 20 is a sectional view section of the dielectric filter of FIG. 19 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The constitution of a dielectric filter according to a first embodiment of the present invention is described referring to FIG. 1 through FIG. 3 .
FIG. 1 is an assembly view of a dielectric filter. A three-order filter is constituted by using electrodes 2 , 3 having openings opposing to each other across the dielectric plate 1 on each side of the dielectric plate 1 . Reference numerals 4 a, 4 b and 4 c denote openings in the electrodes 2 . Numeral 6 denotes a substrate on which input/output lines 7 a, 7 b and a coupling line 15 to be coupled with a dielectric resonator are formed. Because grounding electrodes are formed approximately on the whole area of the lower side of the substrate, the input/output lines 7 a, 7 b and the coupling line 15 constitute a micro-strip line, respectively. The substrate 6 is a printed circuit board of 3.5 in dielectric constant and 0.3 mm in thickness, the line width of the input/output lines 7 a, 7 b is 0.62 mm, and their characteristic impedance is 50 Q. The line width of the coupling line 15 is 0.2 mm. 8 denotes a package adhered to the substrate 6 , which is provided with a frame 9 and a resonance space limiting part 10 . 11 denotes a radio wave absorber, which absorbs the spurious wave of the parallel plate mode or the like to be generated between the electrodes 2 and 3 of the dielectric plate. 12 denotes a cover formed of a metallic sheet, which is joined to an upper surface of the frame part 9 of the package 8 by soldering or the like.
FIG. 2 is a top plan view of the substrate 6 and illustrates two different examples. In both examples of FIG. 2 A and FIG. 2B, the lines 7 a, 7 b for input/output are formed on the upper surface of the substrate 6 at the coupling position with a first-stage resonator and a third-stage resonator. Grounding electrodes 13 are formed in an area which is not used for the resonance space of three resonators. The grounding electrodes are formed over the whole area of the lower side of the substrate 6 , and the grounding electrodes on the lower side are electrically connected to the grounding electrodes on the upper side through a plurality of through holes 14 . 15 denotes a coupling line for polarization, and each end of which is arranged at the coupling position with the third-stage resonator. However, the extending direction of each end of the coupling line for polarization is different between FIG. 2 A and FIG. 2 B.
In FIG. 2A, three resonators resonate in the TE010 mode, and adjacent resonators are magnetically coupled, i.e., inductively coupled with each other. Regarding the direction of the electric field at the instant in the TE010 mode of these three resonators, for example, the first-stage resonator has clockwise polarity, the second-stage resonator has counterclockwise polarity, and the third-stage resonator has clockwise polarity. Thus, the direction of the current flowing in the coupling line 15 is the same. The line length of the coupling line 15 is one half (λg/2) of one wavelength (hereinafter, referred to as λg) on the line at the resonance frequency of the resonator. The coupling line 15 is magnetically coupled, i.e., inductively coupled with the first-stage and the third-stage resonators, respectively, and because the line length of the coupling line 15 is λg/2, the phase difference at the coupling line for polarization becomes π, and the first-stage resonator is capacitively coupled with the third-stage resonator. Thus, two resonators which may be separated from each other by one stage are jump-coupled through capacitive coupling.
In the example in FIG. 2B, the coupling line 15 is magnetically coupled, i.e., inductively coupled with the first-stage resonator and the third-stage resonator, respectively, but the extending direction at each end of the coupling line 15 is opposite to each other, and the phase difference on the coupling line 15 is π, and the first-stage resonator is inductively coupled with the third-stage resonator. Thus, two resonators which may be separated from each other by one stage are jump-coupled through the inductive coupling.
FIG. 3A illustrates the passing characteristic of a dielectric filter having no coupling line for polarization, FIG. 3B illustrates the passing characteristic of the dielectric filter shown in FIG. 2A, and FIG. 3C illustrates the passing characteristic of the dielectric filter shown in FIG. 2B, respectively. As illustrated in FIG. 2A, an attenuation pole is generated on the low-frequency side of the passing band by achieving the inductive coupling between adjacent resonators, and achieving the jump-coupling of two resonators which may be separated from each other by one stage through the capacitive coupling. On the contrary, as illustrated in FIG. 2B, an attenuation pole is generated on the high-frequency side of the passing band by achieving the inductive coupling between adjacent resonators, and achieving the jump-coupling of two resonators which may be separated from each other by one stage through the inductive coupling.
Large attenuation on the low-frequency side or the high-frequency side of the passing band can thus be secured by forming an attenuation pole on the low-frequency side or the high-frequency side of the passing band.
Next, the constitution of a dielectric filter according to a second embodiment is described referring to FIG. 4 through FIG. 6 .
FIG. 4 is a whole assembly view. Different from the example illustrated in FIG. 1, electrode non-forming parts 4 a, 4 b, 4 c, 4 d and 4 e of electrodes 2 , 3 provided on each side of a dielectric plate 1 are rectangular in shape in this example. An substrate 6 is 3.5 mm in dielectric constant and 0.2 mm in thickness, lines 7 a, 7 b for input/output are micro-strip lines of 0.4 mm in line width and 50 Ω in characteristic impedance. A coupling line 15 is a micro-strip line of 0.1 mm in line width.
The dielectric constant of the dielectric plate 1 is 24, and the tanδ is 2.9×10−4 (at 10 GHz), and the resonance frequency of a formed resonator is 38 GHz. The wavelength λg on the coupling line for polarization at the frequency of 38 GHz is approximately 5.0 mm.
FIG. 5 is a top plan view of the substrate 6 , illustrating three different examples. The lines 7 a and 7 b for input/output are formed on the upper surface of the substrate 6 , and respectively and magnetically coupled with an initial-stage resonator at a part of an electrode non-forming part 4 e and with a final-stage resonator at a part of an electrode non-forming part 4 a which are formed on the dielectric filter 1 illustrated in FIG. 4. A coupling line 15 to jump-couple a second-stage resonator with a fourth-stage resonator is also formed. In addition, a grounding electrode 13 is formed on a part to achieve the conductive adhesion of a package 8 , and electrically connected to a grounding electrode approximately over the whole area of the lower side via through holes 14 .
In this embodiment, the basic mode of the rectangular slot mode is used for the first-stage resonator and a fifth-stage resonator, while the double mode (second harmonic) of the rectangular slot mode is used in second-stage, third-stage and fourth-stage resonator.
The arrows in FIG. 5 indicate the direction of the electric field distribution. Adjacent resonators are magnetically coupled, i.e., inductively coupled. In an example of FIG. 5A, the line length of the coupling line 15 is 7.5 mm, i.e., 1.5 λg (electric length 3π=π), and the phase is inverted on the coupling line 15 . The coupling line 15 is inductively coupled with the second-stage resonator and the fourth-stage resonator, respectively, and the second-stage resonator is jump-coupled with the fourth-stage resonator through capacitive coupling because the phase is inverted on the coupling line 15 .
FIG. 6 shows the passing characteristic of the abovementioned dielectric filter. As illustrated in FIG. 5A, an attenuation pole is generated on the low-frequency side of the passing band as illustrated in FIG. 6B by inductively coupling adjacent resonators with each other, and jump-coupling two resonators which may be separated from each other by one stage through the capacitive coupling.
In an example illustrated in FIG. 5B, the line length of the coupling line 15 is 5.0 mm, i.e., λg (electric length 2π=0), and the phase is same at each end of the coupling line 15 . Because the coupling line 15 is inductively coupled with the second-stage resonator and the fourth-stage resonator, respectively, the second-stage resonator is jump-coupled with the fourth-stage resonator through inductive coupling.
In an example illustrated in FIG. 5C, the line length of the coupling line 15 is 7.5 mm, i.e., 1.5 λg (electric length 3π=π). However, the respective directions of the current flowing in the coupling line 15 at its two ends become opposite to each other, and the phase is eventually the same, and the second-stage resonator is jump-coupled with the fourth-stage resonator through the inductive coupling. An attenuation pole is thus generated on the high-frequency side of the passing band as illustrated in FIG. 6C by inductively coupling adjacent resonators, and jump-coupling two resonators which may be separated from each other by one stage through the inductive coupling.
FIG. 7 and FIG. 8 are the constitution of a dielectric filter according to a third embodiment. FIG. 7 is an assembly view, and FIG. 8 is a bottom plan view of a cover. In the first and second embodiments, the coupling line for polarization is formed together with the line for input/output on the substrate, but in an example illustrated in FIG. 7, a cover 16 is a printed circuit board, and a coupling line 19 for polarization is formed on its lower side (a surface opposite to a dielectric plate 2 ). Grounding electrodes 17 are formed on the whole area of the upper side (outer surface) of the cover 16 and a peripheral part of the lower side, and the grounding electrodes on both sides are electrically connected via through holes 18 . The coupling line 19 for polarization is simultaneously patterned in forming these grounding electrodes.
In this example, an attenuation pole is formed on the low-frequency side of the passing band by setting the line length of the coupling line 19 for polarization to be λg/2 (electric length π), and jump-coupling a first-stage resonator with a third-stage resonator through the capacity coupling.
Next, the constitution of three dielectric filters according to a fourth embodiment is illustrated in FIG. 9 through FIG. 11 . In these figures, FIGS. 9A, 10 A and 11 A show a lower side (inner surface) of a cover formed by a printed circuit board, and FIGS. 9B, 10 B and 11 B show a top plan view of an substrate. The basic constitution is similar to that shown in FIG. 2, FIG. 7 and FIG. 8, a coupling line 19 for polarization of λg/2 in line length is formed at the prescribed position of the lower side of a cover 16 , and lines 7 a and 7 b for input/output and a coupling line 15 of λg/2 in line length are formed at the prescribed position on the upper surface of an substrate 6 . Four resonators are arranged on a dielectric plate. The dotted line in the figure indicates the position of four resonators.
In an example illustrated in FIG. 9, the coupling 19 for polarization on the lower side of the cover 16 is formed to jumpcouple a first-stage resonator with a third-stage resonator through the capacitive coupling. The coupling line 15 on the substrate 6 side is formed to jump-couple a second-stage resonator with a fourth-stage resonator through the capacitive coupling.
In an example illustrated in FIG. 10, the coupling line 19 for polarization on the lower side of the cover 16 is formed at the position to jump-couple the second-stage resonator with the fourth-stage resonator through the inductive coupling, and the coupling line 15 on the upper side of the substrate 6 is formed at the position to jump-couple the first-stage resonator with the third-stage resonator through the inductive coupling.
Similarly, in an example illustrated in FIG. 11, the coupling line 19 for polarization on the cover 16 is formed at the position to jump-couple the second-stage resonator with the fourth-stage resonator through the inductive coupling, and the coupling line 15 on the substrate 6 is formed at the position to jump-couple the first-stage resonator with the third-stage resonator through the capacitive coupling.
FIGS. 12A-12C indicate the passing characteristics of three dielectric filters illustrated in FIG. 9 through FIG. 11 . As illustrated in FIG. 9, two attenuation poles are generated on the low-frequency side of the passing band as illustrated in FIG. 12A by providing two sets of jump-coupling circuits to respectively and inductively couple adjacent resonators, and to capacitively couple resonators which may be separated from each other by one stage. Similarly, two attenuation poles are generated on the high-frequency side of the passing band as illustrated in FIG. 12B by providing two sets of jump-coupling circuits to respectively and inductively couple adjacent resonators, and to inductively couple resonators which may be separated from each other by one stage. The prescribed attenuation can be secured over the prescribed band on the low-frequency side or the high-frequency side of the passing band by forming two attenuation poles at the positions adjacent to each other. The position (frequency) of two attenuation poles may be determined according to the band and the attenuation to be secured.
Further, as illustrated in FIG. 11, an attenuation pole can be respectively formed on the low-frequency side and the high-frequency side of the passing band as illustrated in FIG. 12C by inductively coupling adjacent resonators, jump-coupling two resonators which may be separated from each other by one stage on one side through capacitive coupling, and jump-coupling adjacent resonators which may be separated from each other by one stage on the other side through inductive coupling.
In the examples illustrated in FIG. 9 through FIG. 11, the line length of the coupling line for polarization is λg/2, but an attenuation can be respectively formed both on the low-frequency side and on the high-frequency side of the passing band by providing the coupling line for polarization having the line length of e.g., λg on the substrate or the cover, and jump-coupling the first-stage resonator with the fourth-stage resonator through capacitive coupling.
Next, the constitution of a dielectric filter according to a fifth embodiment is illustrated in FIG. 13 and FIG. 14 . FIG. 13 is an assembly view, and FIG. 14 is a top plan view of a dielectric plate. In this embodiment, a coupling line 20 for polarization is formed on a dielectric plate 1 . Electrodes 2 , 3 having electrode non-forming parts opposite to each other are formed on each side of the dielectric plate 1 , and the coupling line 20 for polarization by the slot line is also formed thereon. The slot line is formed at the symmetrical position of the upper and lower sides of the dielectric plate 1 , forming the slot line of vertically symmetrical type. Each end part of the coupling line 20 for polarization is brought close to electrode non-forming parts 4 a and 4 c, realizing the magnetic coupling therebetween. The dotted line in FIG. 14 indicates the condition of the magnetic coupling. In this structure, the first-stage resonator is jump-coupled with the third-stage resonator through the coupling line for polarization by the slot line.
In each above-mentioned embodiment, other modes can be used similarly though the TE010 mode of the resonator is used in a structure where circular electrode non-forming parts are provided on the dielectric plate. For example, in a case where the HE110 mode is used, the constitution illustrated in FIG. 15 can be used. FIG. 15 is a plan view of an substrate. In FIG. 15, the dotted line indicates the position of three electrode non-forming parts formed on the dielectric plate arranged on an substrate 6 . The arrows in the figure indicate the electric field distribution of the HE110 mode of the resonator by these electrode non-forming parts. Lines 7 a and 7 b for input/output by the micro-strip line and a coupling line 15 by the micro-strip line are formed on the substrate 6 . As illustrated in the figure, when the coupling line 15 is arranged for the resonator art, one end of the coupling line 15 is magnetically coupled with the HE110 mode of the first-stage resonator, and the other end is magnetically coupled with the HE110 mode of the third-stage resonator.
Further, in an example illustrated in FIG. 14, a slot line is formed in a dielectric plate, but a coupling line for polarization formed on the dielectric plate provided with a resonator may be a coplanar line as illustrated in FIG. 16 . FIG. 16 is a top plan view of the dielectric plate. An electrode 2 having electrode non-forming parts 4 a, 4 b and 4 c of the same shape which are opposite to each other across a dielectric plate 1 is formed on each side of the dielectric plate 1 , and at the same time, a coupling line 21 for polarization by the coplanar line of the same shape is formed on each side across the dielectric plate 1 . The arrows in the figure show the condition of the electric field distribution. The resonators by the electrode non-forming parts 4 a, 4 b and 4 c achieve the electric field coupling by respectively projecting each end part of a center conductor of a coplanar line 21 to a center part of the electrode non-forming parts 4 a and 4 c making use of the basic mode of the rectangular slot mode, respectively. A jump-coupling circuit can also be constituted by using the coplanar line.
FIG. 17 is a view to illustrate the constitution of a transmission/reception sharing device. The basic constitution as a whole is similar to those illustrated in FIG. 4 and FIG. 5, except that a transmission filter and a reception filter are constituted in one device. That is, a structure illustrated in FIG. SA is applied to the transmission filter part, while a structure illustrated in FIG. 5B is applied to the reception filter part. The dotted line in the figure indicates the position of electrode nonforming parts of a dielectric plate arranged on an upper part of an substrate 6 . Lines 7 a and 7 b for input/output are respectively coupled with a first-stage resonator and a fifth-stage resonator of the transmission filter, and lines 7 c and 7 d for input/output are respectively coupled with a first-stage resonator and a fifth-stage resonator of the reception filter part. A coupling line 15 a for polarization is jump-coupled with a second-stage resonator and a fourth-stage resonator of the transmission filter through the capacitive coupling. A coupling line 15 b for polarization is coupled with the second-stage resonator and the fourth-stage resonator of the reception filter through the inductive coupling. The electric length from a branch point of a line 7 e for input/output from the lines 7 b and 7 c to the equivalent short-circuit surface of the resonator at a final stage (the fifth stage) of the transmission filter is an odd-number times (electric length π/2) λg/4 in terms of the wavelength on the line in the reception frequency band, and the electric length from the above-mentioned branch point to the equivalent short-circuit surface of the resonator of the initial stage (the first stage) of the reception filter is the odd-number times of λg/4 (electric length π/2) on the line in the transmission frequency band. The transmission signal is thus branched from the reception signal.
A transmission/reception sharing device provided with a transmission filter having an attenuation pole on the low-frequency side of the passing band and a reception filter having an attenuation pole on the high-frequency side of the passing band, is thus obtained. Large coupling attenuation between a transmitter and a receiver can be secured by selecting the attenuation pole of the transmission filter to be the reception frequency band, and selecting the attenuation pole of the reception filter to be the transmission frequency band.
FIG. 18 is a view illustrating the constitution of a communication device in which the above-mentioned transmission/reception sharing device is used as an antenna multicoupler (duplexer), where 46 a denotes the above-mentioned reception filter, 46 b denotes the above-mentioned transmission filter, and 46 denotes an antenna multicoupler. As illustrated in the figure, a reception circuit 47 is connected to a reception signal output port 46 c of the antenna multicoupler 46 , and a power source circuit 48 is connected to a transmission signal input port 46 d, respectively, and an antenna 49 is connected to an antenna port 46 e to constitute a transmitter 50 as a whole.
The dielectric filter of the present invention can be provided on a high-frequency circuit part of a communication device, not limited to the antenna multicoupler, and a communication device which is miniaturized and weight-reduced can be provided taking advantage of the characteristics of being compact in size, low in loss and excellent in selectivity.
The present invention, carried out as described above, provides the following advantages.
Because a coupling line for polarization is provided on a substrate, no parts such as a semi-rigid cable are projected outside, preventing the increase in size, and any dead space when mounted in communications equipment. Because the dimensional accuracy of the coupling line for polarization can be easily increased, the characteristic variance is small, and the desired characteristic can be obtained with excellent reproducibility.
Because no special substrate is necessary to provide the coupling line for polarization other than a substrate on which a line for signal input/output is provided, not only is the size of the equipment not increased, but also no special manufacturing process to form the coupling line for polarization is necessary, and the manufacturing cost is not increased.
The substrate provided with the coupling line for polarization can be used as a shield cover, and any member of a shield cover single body can be dispensed with in this structure, and the shield cover can be constituted by a small number of parts.
A substrate for forming the coupling line for polarization can be dispensed with, the number of parts can be reduced, and no special processes for forming the coupling line for polarization are needed for providing a coupling line for polarization on a dielectric plate where a resonator is provided.
A transmission/reception sharing device and a communication device which are more miniaturized and weight-reduced can be obtained taking advantage of the characteristic of being compact in size, low in loss and excellent in selectivity.
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. Therefore, the present invention is not limited by the specific disclosure herein. | Lines for input/output to be respectively coupled with two resonators formed on a dielectric plate, and a coupling line for polarization to be respectively coupled with two resonators which may be separated from each other by one or more other stages to achieve the jump-coupling between the resonators, are respectively formed on an substrate in order to solve problems including the increase in dead space, the increase in the machining and assembly processes for forming a coupling loop, and the reproductivity of characteristics which are caused by using a cable for jump-coupling in polarizing a dielectric filter of planar circuit type. | Identify and summarize the most critical features from the given passage. | [
"This is a divisional of U.S. patent application Ser.",
"No. 09/335,346, filed Jun. 17, 1999, abandoned, in the name of Toshiro Hiratsuka, Tomiya Sonoda, Shigeyuki Mikami and Kiyoshi Kanagawa, titled DIELECTRIC FILTER TRANSMISSION/RECEPTION SHARING DEVICE AND COMMUNICATION DEVICE, now abandoned.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present invention relates to a dielectric filter in which a resonator is formed on a dielectric plate, a transmission/reception sharing device and a communication device using the dielectric filter.",
"Description of the Related Art A bandpass filter having a plurality of resonators in series has been used in a communication device.",
"To obtain large attenuation above and below a pass band, the so called “jump-coupling method”",
"has been utilized.",
"In accordance with the method, a pair of resonators are directly electromagnetically coupled to each other jumping over another resonator therebetween.",
"By causing the jump-coupling, a notch or pole appears outside the pass band On the other hand, a planar-circuit type dielectric filter is expected to be widely used in a wireless LAN, a portable visual telephone and a next generation satellite broadcasting system.",
"These applications use sub-millimeter waves.",
"This type of filter is described in Japanese Patent Application No. 9-103017.",
"It should be noted that the Japanese application was not laid-open to the public at the time of filing Japanese Patent Application No. 10-171174 on which this case is based.",
"Thus, the reference is provided as background information to show the state of the art only.",
"The citation of the reference is not to be construed as an admission that it constitutes prior art.",
"The application No. JP-A-9-103017 discloses a dielectric filter in which an electrode is formed on each side of a dielectric plate to constitute a resonator at the prescribed position of the dielectric plate, a micro-strip line is formed on a substrate, and the micro-strip line is coupled with the dielectric resonator.",
"This dielectric filter is extremely advantageous, being compact in size, easy to manufacture, and capable of easily obtaining the desired characteristics.",
"The above-mentioned jump-coupling is also effective to secure the large attenuation on the high-frequency side or the low-frequency side of its pass band of the planar circuit type dielectric filter.",
"An example is illustrated in FIG. 19 and FIG. 20, where the above-mentioned filter device in which a part of the dielectric plate is used as the resonator and a structure for causing jump-coupling between the resonators is implemented.",
"FIG. 19 is an assembly view in which electrodes 2 , 3 having electrode-free parts of the same shape opposite to each other across a dielectric plate are provided on each side of the dielectric plate 1 to constitute a third-order filter.",
"Numerals 4 a, 4 b and 4 c denote electrode-free parts on the upper surface thereof.",
"Numeral 6 denotes a substrate on which a microstrip line to be coupled with the resonator is formed, and a basic part of the dielectric filter is constituted by successively laminating a package 8 , the dielectric plate 1 , an electromagnetic wave absorption body 11 and a shield 12 comprising a metallic plate thereon.",
"In order to cause a pole outside the pass band, a semi-rigid cable in which a coupling loop is formed on each end is provided on the shield 12 in order to cause jump-coupling between a first-stage resonator and a third-stage resonator as illustrated in the figures.",
"FIG. 20 illustrates a sectional view of the abovementioned dielectric filter.",
"The filter device has a higher profile because of the diameter of the semi-rigid cable.",
"Thus, a dead space may be produced when the filter device is installed in electronic equipment.",
"Also, a separate semi-rigid cable is necessary, the assembly process requires machining and soldering to form the coupling loop, and the cost is increased as a whole.",
"Further, because the position of an attenuation pole is largely changed depending on the direction, length, etc.",
", of the coupling loop, it is relatively difficult to adjust the position of the cable to obtain a desired filter characteristic.",
"SUMMARY OF THE INVENTION The present invention provides a dielectric filter in which the above-mentioned problems caused by using separate parts such as a semi-rigid cable are solved, and a transmission/reception sharing device and communication device using the dielectric filter.",
"In the present invention, an electrode having electrode-free parts opposite to each other, on opposite sides of a dielectric plate, is provided on each side of the dielectric plate, an area between the electrode electrode-free parts is a resonator, and a plurality of stages of resonators in which adjacent resonators are successively coupled with each other, are provided on the dielectric plate.",
"A coupling line for polarization, which directly couples two resonators by respectively coupling the line with the two resonators which may be separated from each other by one or more other stages among a plurality of resonators, is provided on a substrate separated from the dielectric plate by a prescribed distance.",
"In such a structure, the coupling line for polarization is provided on the substrate, and no parts such as the semi-rigid cable are projected outside, and the device is not increased in size.",
"In the present invention, a line for signal input/output to be coupled with prescribed resonators is provided on the substrate provided with the coupling line for causing a pole.",
"This structure dispenses with a special substrate on which a coupling line for causing a pole is provided in addition to a substrate on which the line for signal input/output is provided.",
"The substrate provided with the coupling line is used as a shield cover by forming an electrode on approximately the whole surface opposite to a surface on which the coupling line for polarization is formed.",
"The structure dispenses with a single shield cover, and also dispenses with a substrate exclusively used for forming the coupling line for polarization.",
"In the present invention, an electrode having openings of approximately same shape which are opposite to each other, on opposite sides of a dielectric plate, is provided on each side of the dielectric plate, an area between the openings is a resonator, and a plurality of stages of resonators in which adjacent resonators are successively coupled with each other, are provided on the dielectric plate.",
"A coupling line for polarization, which directly couples two resonators, e.g., through a slot line, by respectively coupling the line with the two resonators which may be separated from each other by one or more other stages among a plurality of resonators, is provided on the substrate.",
"Such a structure dispenses with a substrate for forming the coupling line for polarization, and simultaneous patterning is realized in forming resonators.",
"Also, in the present invention, a transmission/reception sharing device is constituted by providing either of the above-mentioned dielectric filters as a transmission filter, a reception filter, or both filters.",
"Further, in the present invention, a communication device is constituted by providing the dielectric filter in a high-frequency circuit part, or in a transmission/reception sharing device such as, for example, an antenna.",
"Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an assembly view of a dielectric filter according to a first embodiment;",
"FIG. 2 is a top plan view of a substrate of the dielectric filter;",
"FIG. 3 is a characteristic graph of the dielectric filter;",
"FIG. 4 is an assembly view of a dielectric filter according to a second embodiment;",
"FIG. 5 is a top plan view of a substrate of the dielectric filter;",
"FIG. 6 is a characteristic graph of the dielectric filter;",
"FIG. 7 is an assembly view of a dielectric filter according to a third embodiment;",
"FIG. 8 is a bottom plan view of a cover of the dielectric filter;",
"FIG. 9 is a bottom plan view of a cover and a top plan view of a substrate of a dielectric filter according to a fourth embodiment;",
"FIG. 10 is a bottom plan view of a cover and a top plan view of a substrate of another dielectric filter according to the fourth embodiment;",
"FIG. 11 is a bottom plan view of a cover and a top plan view of a substrate of still another dielectric filter according to the fourth embodiment;",
"FIG. 12 is a characteristic graph of the dielectric filters illustrated in FIG. 9 through FIG. 11;",
"FIG. 13 is an assembly view of a dielectric filter according to a fifth embodiment;",
"FIG. 14 is a top plan view of a dielectric plate of the dielectric filter;",
"FIG. 15 is a top plan view of an substrate of a dielectric filter making use of the HE110 mode;",
"FIG. 16 is a top plan view of a dielectric plate of a dielectric filter where a coplanar line is a line for polarization;",
"FIG. 17 is a top plan view of an substrate of a transmission/reception sharing device;",
"FIG. 18 is a block diagram to illustrate the constitution of a communication device;",
"FIG. 19 is an assembly view of a conventional dielectric filter;",
"and FIG. 20 is a sectional view section of the dielectric filter of FIG. 19 .",
"DESCRIPTION OF THE PREFERRED EMBODIMENTS The constitution of a dielectric filter according to a first embodiment of the present invention is described referring to FIG. 1 through FIG. 3 .",
"FIG. 1 is an assembly view of a dielectric filter.",
"A three-order filter is constituted by using electrodes 2 , 3 having openings opposing to each other across the dielectric plate 1 on each side of the dielectric plate 1 .",
"Reference numerals 4 a, 4 b and 4 c denote openings in the electrodes 2 .",
"Numeral 6 denotes a substrate on which input/output lines 7 a, 7 b and a coupling line 15 to be coupled with a dielectric resonator are formed.",
"Because grounding electrodes are formed approximately on the whole area of the lower side of the substrate, the input/output lines 7 a, 7 b and the coupling line 15 constitute a micro-strip line, respectively.",
"The substrate 6 is a printed circuit board of 3.5 in dielectric constant and 0.3 mm in thickness, the line width of the input/output lines 7 a, 7 b is 0.62 mm, and their characteristic impedance is 50 Q. The line width of the coupling line 15 is 0.2 mm.",
"8 denotes a package adhered to the substrate 6 , which is provided with a frame 9 and a resonance space limiting part 10 .",
"11 denotes a radio wave absorber, which absorbs the spurious wave of the parallel plate mode or the like to be generated between the electrodes 2 and 3 of the dielectric plate.",
"12 denotes a cover formed of a metallic sheet, which is joined to an upper surface of the frame part 9 of the package 8 by soldering or the like.",
"FIG. 2 is a top plan view of the substrate 6 and illustrates two different examples.",
"In both examples of FIG. 2 A and FIG. 2B, the lines 7 a, 7 b for input/output are formed on the upper surface of the substrate 6 at the coupling position with a first-stage resonator and a third-stage resonator.",
"Grounding electrodes 13 are formed in an area which is not used for the resonance space of three resonators.",
"The grounding electrodes are formed over the whole area of the lower side of the substrate 6 , and the grounding electrodes on the lower side are electrically connected to the grounding electrodes on the upper side through a plurality of through holes 14 .",
"15 denotes a coupling line for polarization, and each end of which is arranged at the coupling position with the third-stage resonator.",
"However, the extending direction of each end of the coupling line for polarization is different between FIG. 2 A and FIG. 2 B. In FIG. 2A, three resonators resonate in the TE010 mode, and adjacent resonators are magnetically coupled, i.e., inductively coupled with each other.",
"Regarding the direction of the electric field at the instant in the TE010 mode of these three resonators, for example, the first-stage resonator has clockwise polarity, the second-stage resonator has counterclockwise polarity, and the third-stage resonator has clockwise polarity.",
"Thus, the direction of the current flowing in the coupling line 15 is the same.",
"The line length of the coupling line 15 is one half (λg/2) of one wavelength (hereinafter, referred to as λg) on the line at the resonance frequency of the resonator.",
"The coupling line 15 is magnetically coupled, i.e., inductively coupled with the first-stage and the third-stage resonators, respectively, and because the line length of the coupling line 15 is λg/2, the phase difference at the coupling line for polarization becomes π, and the first-stage resonator is capacitively coupled with the third-stage resonator.",
"Thus, two resonators which may be separated from each other by one stage are jump-coupled through capacitive coupling.",
"In the example in FIG. 2B, the coupling line 15 is magnetically coupled, i.e., inductively coupled with the first-stage resonator and the third-stage resonator, respectively, but the extending direction at each end of the coupling line 15 is opposite to each other, and the phase difference on the coupling line 15 is π, and the first-stage resonator is inductively coupled with the third-stage resonator.",
"Thus, two resonators which may be separated from each other by one stage are jump-coupled through the inductive coupling.",
"FIG. 3A illustrates the passing characteristic of a dielectric filter having no coupling line for polarization, FIG. 3B illustrates the passing characteristic of the dielectric filter shown in FIG. 2A, and FIG. 3C illustrates the passing characteristic of the dielectric filter shown in FIG. 2B, respectively.",
"As illustrated in FIG. 2A, an attenuation pole is generated on the low-frequency side of the passing band by achieving the inductive coupling between adjacent resonators, and achieving the jump-coupling of two resonators which may be separated from each other by one stage through the capacitive coupling.",
"On the contrary, as illustrated in FIG. 2B, an attenuation pole is generated on the high-frequency side of the passing band by achieving the inductive coupling between adjacent resonators, and achieving the jump-coupling of two resonators which may be separated from each other by one stage through the inductive coupling.",
"Large attenuation on the low-frequency side or the high-frequency side of the passing band can thus be secured by forming an attenuation pole on the low-frequency side or the high-frequency side of the passing band.",
"Next, the constitution of a dielectric filter according to a second embodiment is described referring to FIG. 4 through FIG. 6 .",
"FIG. 4 is a whole assembly view.",
"Different from the example illustrated in FIG. 1, electrode non-forming parts 4 a, 4 b, 4 c, 4 d and 4 e of electrodes 2 , 3 provided on each side of a dielectric plate 1 are rectangular in shape in this example.",
"An substrate 6 is 3.5 mm in dielectric constant and 0.2 mm in thickness, lines 7 a, 7 b for input/output are micro-strip lines of 0.4 mm in line width and 50 Ω in characteristic impedance.",
"A coupling line 15 is a micro-strip line of 0.1 mm in line width.",
"The dielectric constant of the dielectric plate 1 is 24, and the tanδ is 2.9×10−4 (at 10 GHz), and the resonance frequency of a formed resonator is 38 GHz.",
"The wavelength λg on the coupling line for polarization at the frequency of 38 GHz is approximately 5.0 mm.",
"FIG. 5 is a top plan view of the substrate 6 , illustrating three different examples.",
"The lines 7 a and 7 b for input/output are formed on the upper surface of the substrate 6 , and respectively and magnetically coupled with an initial-stage resonator at a part of an electrode non-forming part 4 e and with a final-stage resonator at a part of an electrode non-forming part 4 a which are formed on the dielectric filter 1 illustrated in FIG. 4. A coupling line 15 to jump-couple a second-stage resonator with a fourth-stage resonator is also formed.",
"In addition, a grounding electrode 13 is formed on a part to achieve the conductive adhesion of a package 8 , and electrically connected to a grounding electrode approximately over the whole area of the lower side via through holes 14 .",
"In this embodiment, the basic mode of the rectangular slot mode is used for the first-stage resonator and a fifth-stage resonator, while the double mode (second harmonic) of the rectangular slot mode is used in second-stage, third-stage and fourth-stage resonator.",
"The arrows in FIG. 5 indicate the direction of the electric field distribution.",
"Adjacent resonators are magnetically coupled, i.e., inductively coupled.",
"In an example of FIG. 5A, the line length of the coupling line 15 is 7.5 mm, i.e., 1.5 λg (electric length 3π=π), and the phase is inverted on the coupling line 15 .",
"The coupling line 15 is inductively coupled with the second-stage resonator and the fourth-stage resonator, respectively, and the second-stage resonator is jump-coupled with the fourth-stage resonator through capacitive coupling because the phase is inverted on the coupling line 15 .",
"FIG. 6 shows the passing characteristic of the abovementioned dielectric filter.",
"As illustrated in FIG. 5A, an attenuation pole is generated on the low-frequency side of the passing band as illustrated in FIG. 6B by inductively coupling adjacent resonators with each other, and jump-coupling two resonators which may be separated from each other by one stage through the capacitive coupling.",
"In an example illustrated in FIG. 5B, the line length of the coupling line 15 is 5.0 mm, i.e., λg (electric length 2π=0), and the phase is same at each end of the coupling line 15 .",
"Because the coupling line 15 is inductively coupled with the second-stage resonator and the fourth-stage resonator, respectively, the second-stage resonator is jump-coupled with the fourth-stage resonator through inductive coupling.",
"In an example illustrated in FIG. 5C, the line length of the coupling line 15 is 7.5 mm, i.e., 1.5 λg (electric length 3π=π).",
"However, the respective directions of the current flowing in the coupling line 15 at its two ends become opposite to each other, and the phase is eventually the same, and the second-stage resonator is jump-coupled with the fourth-stage resonator through the inductive coupling.",
"An attenuation pole is thus generated on the high-frequency side of the passing band as illustrated in FIG. 6C by inductively coupling adjacent resonators, and jump-coupling two resonators which may be separated from each other by one stage through the inductive coupling.",
"FIG. 7 and FIG. 8 are the constitution of a dielectric filter according to a third embodiment.",
"FIG. 7 is an assembly view, and FIG. 8 is a bottom plan view of a cover.",
"In the first and second embodiments, the coupling line for polarization is formed together with the line for input/output on the substrate, but in an example illustrated in FIG. 7, a cover 16 is a printed circuit board, and a coupling line 19 for polarization is formed on its lower side (a surface opposite to a dielectric plate 2 ).",
"Grounding electrodes 17 are formed on the whole area of the upper side (outer surface) of the cover 16 and a peripheral part of the lower side, and the grounding electrodes on both sides are electrically connected via through holes 18 .",
"The coupling line 19 for polarization is simultaneously patterned in forming these grounding electrodes.",
"In this example, an attenuation pole is formed on the low-frequency side of the passing band by setting the line length of the coupling line 19 for polarization to be λg/2 (electric length π), and jump-coupling a first-stage resonator with a third-stage resonator through the capacity coupling.",
"Next, the constitution of three dielectric filters according to a fourth embodiment is illustrated in FIG. 9 through FIG. 11 .",
"In these figures, FIGS. 9A, 10 A and 11 A show a lower side (inner surface) of a cover formed by a printed circuit board, and FIGS. 9B, 10 B and 11 B show a top plan view of an substrate.",
"The basic constitution is similar to that shown in FIG. 2, FIG. 7 and FIG. 8, a coupling line 19 for polarization of λg/2 in line length is formed at the prescribed position of the lower side of a cover 16 , and lines 7 a and 7 b for input/output and a coupling line 15 of λg/2 in line length are formed at the prescribed position on the upper surface of an substrate 6 .",
"Four resonators are arranged on a dielectric plate.",
"The dotted line in the figure indicates the position of four resonators.",
"In an example illustrated in FIG. 9, the coupling 19 for polarization on the lower side of the cover 16 is formed to jumpcouple a first-stage resonator with a third-stage resonator through the capacitive coupling.",
"The coupling line 15 on the substrate 6 side is formed to jump-couple a second-stage resonator with a fourth-stage resonator through the capacitive coupling.",
"In an example illustrated in FIG. 10, the coupling line 19 for polarization on the lower side of the cover 16 is formed at the position to jump-couple the second-stage resonator with the fourth-stage resonator through the inductive coupling, and the coupling line 15 on the upper side of the substrate 6 is formed at the position to jump-couple the first-stage resonator with the third-stage resonator through the inductive coupling.",
"Similarly, in an example illustrated in FIG. 11, the coupling line 19 for polarization on the cover 16 is formed at the position to jump-couple the second-stage resonator with the fourth-stage resonator through the inductive coupling, and the coupling line 15 on the substrate 6 is formed at the position to jump-couple the first-stage resonator with the third-stage resonator through the capacitive coupling.",
"FIGS. 12A-12C indicate the passing characteristics of three dielectric filters illustrated in FIG. 9 through FIG. 11 .",
"As illustrated in FIG. 9, two attenuation poles are generated on the low-frequency side of the passing band as illustrated in FIG. 12A by providing two sets of jump-coupling circuits to respectively and inductively couple adjacent resonators, and to capacitively couple resonators which may be separated from each other by one stage.",
"Similarly, two attenuation poles are generated on the high-frequency side of the passing band as illustrated in FIG. 12B by providing two sets of jump-coupling circuits to respectively and inductively couple adjacent resonators, and to inductively couple resonators which may be separated from each other by one stage.",
"The prescribed attenuation can be secured over the prescribed band on the low-frequency side or the high-frequency side of the passing band by forming two attenuation poles at the positions adjacent to each other.",
"The position (frequency) of two attenuation poles may be determined according to the band and the attenuation to be secured.",
"Further, as illustrated in FIG. 11, an attenuation pole can be respectively formed on the low-frequency side and the high-frequency side of the passing band as illustrated in FIG. 12C by inductively coupling adjacent resonators, jump-coupling two resonators which may be separated from each other by one stage on one side through capacitive coupling, and jump-coupling adjacent resonators which may be separated from each other by one stage on the other side through inductive coupling.",
"In the examples illustrated in FIG. 9 through FIG. 11, the line length of the coupling line for polarization is λg/2, but an attenuation can be respectively formed both on the low-frequency side and on the high-frequency side of the passing band by providing the coupling line for polarization having the line length of e.g., λg on the substrate or the cover, and jump-coupling the first-stage resonator with the fourth-stage resonator through capacitive coupling.",
"Next, the constitution of a dielectric filter according to a fifth embodiment is illustrated in FIG. 13 and FIG. 14 .",
"FIG. 13 is an assembly view, and FIG. 14 is a top plan view of a dielectric plate.",
"In this embodiment, a coupling line 20 for polarization is formed on a dielectric plate 1 .",
"Electrodes 2 , 3 having electrode non-forming parts opposite to each other are formed on each side of the dielectric plate 1 , and the coupling line 20 for polarization by the slot line is also formed thereon.",
"The slot line is formed at the symmetrical position of the upper and lower sides of the dielectric plate 1 , forming the slot line of vertically symmetrical type.",
"Each end part of the coupling line 20 for polarization is brought close to electrode non-forming parts 4 a and 4 c, realizing the magnetic coupling therebetween.",
"The dotted line in FIG. 14 indicates the condition of the magnetic coupling.",
"In this structure, the first-stage resonator is jump-coupled with the third-stage resonator through the coupling line for polarization by the slot line.",
"In each above-mentioned embodiment, other modes can be used similarly though the TE010 mode of the resonator is used in a structure where circular electrode non-forming parts are provided on the dielectric plate.",
"For example, in a case where the HE110 mode is used, the constitution illustrated in FIG. 15 can be used.",
"FIG. 15 is a plan view of an substrate.",
"In FIG. 15, the dotted line indicates the position of three electrode non-forming parts formed on the dielectric plate arranged on an substrate 6 .",
"The arrows in the figure indicate the electric field distribution of the HE110 mode of the resonator by these electrode non-forming parts.",
"Lines 7 a and 7 b for input/output by the micro-strip line and a coupling line 15 by the micro-strip line are formed on the substrate 6 .",
"As illustrated in the figure, when the coupling line 15 is arranged for the resonator art, one end of the coupling line 15 is magnetically coupled with the HE110 mode of the first-stage resonator, and the other end is magnetically coupled with the HE110 mode of the third-stage resonator.",
"Further, in an example illustrated in FIG. 14, a slot line is formed in a dielectric plate, but a coupling line for polarization formed on the dielectric plate provided with a resonator may be a coplanar line as illustrated in FIG. 16 .",
"FIG. 16 is a top plan view of the dielectric plate.",
"An electrode 2 having electrode non-forming parts 4 a, 4 b and 4 c of the same shape which are opposite to each other across a dielectric plate 1 is formed on each side of the dielectric plate 1 , and at the same time, a coupling line 21 for polarization by the coplanar line of the same shape is formed on each side across the dielectric plate 1 .",
"The arrows in the figure show the condition of the electric field distribution.",
"The resonators by the electrode non-forming parts 4 a, 4 b and 4 c achieve the electric field coupling by respectively projecting each end part of a center conductor of a coplanar line 21 to a center part of the electrode non-forming parts 4 a and 4 c making use of the basic mode of the rectangular slot mode, respectively.",
"A jump-coupling circuit can also be constituted by using the coplanar line.",
"FIG. 17 is a view to illustrate the constitution of a transmission/reception sharing device.",
"The basic constitution as a whole is similar to those illustrated in FIG. 4 and FIG. 5, except that a transmission filter and a reception filter are constituted in one device.",
"That is, a structure illustrated in FIG. SA is applied to the transmission filter part, while a structure illustrated in FIG. 5B is applied to the reception filter part.",
"The dotted line in the figure indicates the position of electrode nonforming parts of a dielectric plate arranged on an upper part of an substrate 6 .",
"Lines 7 a and 7 b for input/output are respectively coupled with a first-stage resonator and a fifth-stage resonator of the transmission filter, and lines 7 c and 7 d for input/output are respectively coupled with a first-stage resonator and a fifth-stage resonator of the reception filter part.",
"A coupling line 15 a for polarization is jump-coupled with a second-stage resonator and a fourth-stage resonator of the transmission filter through the capacitive coupling.",
"A coupling line 15 b for polarization is coupled with the second-stage resonator and the fourth-stage resonator of the reception filter through the inductive coupling.",
"The electric length from a branch point of a line 7 e for input/output from the lines 7 b and 7 c to the equivalent short-circuit surface of the resonator at a final stage (the fifth stage) of the transmission filter is an odd-number times (electric length π/2) λg/4 in terms of the wavelength on the line in the reception frequency band, and the electric length from the above-mentioned branch point to the equivalent short-circuit surface of the resonator of the initial stage (the first stage) of the reception filter is the odd-number times of λg/4 (electric length π/2) on the line in the transmission frequency band.",
"The transmission signal is thus branched from the reception signal.",
"A transmission/reception sharing device provided with a transmission filter having an attenuation pole on the low-frequency side of the passing band and a reception filter having an attenuation pole on the high-frequency side of the passing band, is thus obtained.",
"Large coupling attenuation between a transmitter and a receiver can be secured by selecting the attenuation pole of the transmission filter to be the reception frequency band, and selecting the attenuation pole of the reception filter to be the transmission frequency band.",
"FIG. 18 is a view illustrating the constitution of a communication device in which the above-mentioned transmission/reception sharing device is used as an antenna multicoupler (duplexer), where 46 a denotes the above-mentioned reception filter, 46 b denotes the above-mentioned transmission filter, and 46 denotes an antenna multicoupler.",
"As illustrated in the figure, a reception circuit 47 is connected to a reception signal output port 46 c of the antenna multicoupler 46 , and a power source circuit 48 is connected to a transmission signal input port 46 d, respectively, and an antenna 49 is connected to an antenna port 46 e to constitute a transmitter 50 as a whole.",
"The dielectric filter of the present invention can be provided on a high-frequency circuit part of a communication device, not limited to the antenna multicoupler, and a communication device which is miniaturized and weight-reduced can be provided taking advantage of the characteristics of being compact in size, low in loss and excellent in selectivity.",
"The present invention, carried out as described above, provides the following advantages.",
"Because a coupling line for polarization is provided on a substrate, no parts such as a semi-rigid cable are projected outside, preventing the increase in size, and any dead space when mounted in communications equipment.",
"Because the dimensional accuracy of the coupling line for polarization can be easily increased, the characteristic variance is small, and the desired characteristic can be obtained with excellent reproducibility.",
"Because no special substrate is necessary to provide the coupling line for polarization other than a substrate on which a line for signal input/output is provided, not only is the size of the equipment not increased, but also no special manufacturing process to form the coupling line for polarization is necessary, and the manufacturing cost is not increased.",
"The substrate provided with the coupling line for polarization can be used as a shield cover, and any member of a shield cover single body can be dispensed with in this structure, and the shield cover can be constituted by a small number of parts.",
"A substrate for forming the coupling line for polarization can be dispensed with, the number of parts can be reduced, and no special processes for forming the coupling line for polarization are needed for providing a coupling line for polarization on a dielectric plate where a resonator is provided.",
"A transmission/reception sharing device and a communication device which are more miniaturized and weight-reduced can be obtained taking advantage of the characteristic of being compact in size, low in loss and excellent in selectivity.",
"Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art.",
"Therefore, the present invention is not limited by the specific disclosure herein."
] |
BACKGROUND OF THE INVENTION
The invention relates to a method for connecting a user equipment to a network device via a mobile communication network wherein the user equipment comprises at least a deregistered state and a registered state, wherein the deregistered state comprises at least two substates, a normal and an attempting-to-attach substate, for defining a connectivity state of the user equipment to the mobile communication network, and wherein the user equipment is connectable to the mobile communication network and wherein the network device is connected to the mobile communication network
comprising the steps of
a) Paging of the user equipment by a paging signal using a, preferably unique, user equipment identifier, b) Switching to the attempting-to-attach substate of the deregistered state of the user equipment when receiving a paging signal, c) Attaching the user equipment to the mobile communication network, and d) Switching to the registered state of the user equipment depending on a result of the attachment according to step c).
The present invention also relates to a system for connecting a user equipment to a network device via a mobile communication network, wherein the user equipment is formed such to provide at least a deregistered state and a registered state, wherein the deregistered state comprises at least two substates, a normal and an attempting-to-attach substate, for defining a connectivity state of the user equipment to the mobile communication network, and wherein the user equipment is connectable to the mobile communication network and wherein the network device is connected to the mobile communication network, and wherein the user equipment is formed such that on receiving a paging signal due to paging using a, preferably unique, user equipment identifier, the user equipment switches to the attempting-to-attach substate of the deregistered state of the user equipment, attaches to the mobile communication network, and switches to the registered state of the user equipment depending on a result of the attachment according to step c).
Conventional connecting techniques in mobile communication networks, for example a cell phone connecting to a base station of a UMTS mobile communication network and further for example via the UMTS mobile communication network and the internet to a dedicated server, like an email server, have been mainly designed to be used by human beings.
Conventional states of a user equipment, also named mobile terminal or mobile station, comprises therefore in general two operational states in particular regarding registration, namely a deregistered state and a registered state. In addition, in registered state the user equipment can be in two different modes regarding its connection, namely an EMM-connected or an EMM-idle state. When a signalling connection is established the user equipment may be in the registered state in normal-service substate and in a further, additional substate EMM-connected. If a NAS signalling connection is not established the user equipment may be in a substate EMM-idle. When the user equipment is in the registered state, the user equipment may transmit data to respectively via the mobile communication network to a dedicated server for example in the internet. In the deregistered state the user equipment may be in normal substate or in attempting-to-attach state. In the normal deregistered substate the user equipment cannot transmit or receive data but may be able to initiate an attach or a combined attached procedure. For initiating an attach or combined attached procedure the user equipment switches in the deregistered state to an attempting-to-attach substate initiating an attach. When the attach to the mobile communication network is successful the user equipment becomes registered in the mobile communication network and switches to the registered state allowing the transfer of data between the user equipment and the dedicated server. In this normal-service registered state the user equipment may transmit data which, if the user equipment is in EMM-idle, may be initiated by a Service Request NAS signalling message.
FIG. 1 shows a conventional switching of states of a user equipment in a current 3GPP model. When the user equipment is switched on (reference sign 72 ) the user equipment is first in a deregistered state B. After switching on 72 the user equipment likes to become attached to a mobile communication network and therefore tries to register with the mobile communication network as soon as possible. After a successful attach (reference sign 70 a ) the user equipment switches from the deregistered state B to a registered state C. The user equipment also remains registered, i. e. in the normal-service substate, as long as no error condition or restriction from the mobile communication network occurs. The registration is prerequisite to reachability of the user equipment which may be defined via paging based on tracking area information stored in a mobile communication network entity, preferably a mobility management entity and the tracking area information depends on location registration of the user equipment.
However, for new classes of devices, in particular machine type communication devices, conventional registration techniques have a number of drawbacks. For example if a machine type communication device is fixed in a location and scheduled to deliver data once every month via the mobile communication network this would cause costs due to a high energy consumption of the user equipment for being and staying registered in the mobile communication network. Another drawback is that the registration of the machine type communication device creates a signalling overhead and shortens the bandwidth for other especially none-machine-type-communication devices in the mobile communication network. In the registered state the user equipment has to be permanently staying in the necessary context state for example security context, location context, bearer context, etc.
To overcome these drawbacks the user equipment may be switched on and/or off at appropriate times: The user equipment may be switched on for example when an uplink communication, i. e. from the user equipment to the mobile communication network, is necessary: The user equipment then attaches and registers to the mobile communication network and all necessary context is created subsequently. Switching on and off may be handled by local environment devices of the user equipment, for example the user equipment may be communicating with or connected to a timer, counter thresholds, sensors or the like.
Another option to overcome these drawbacks is the use of well-defined time slots for a communication, in particular for the registration process, of the user equipment with the mobile communication network. These time slots are fixed and known to the user equipment and to a predefined entity of the mobile communication network handling the establishment of the connection. This may be implemented for example by attaching the user equipment to a timer device which activates or deactivates the user equipment power switch sufficiently before and after the defined time slots. In order to obtain a reliable bidirectional connection between the user equipment and the mobile communication network the local time of the mobile communication network and the user equipment must be well synchronized.
However this solution has inter alia one main disadvantage: This solution may not be applicable to devices which need to be reachable at all times, since by turning off the user equipment the user equipment is deregistered and is not able to receive any communication signals from the mobile communication network.
SUMMARY OF THE INVENTION
It is therefore an objective of the present invention to provide a method and a system method for connecting a user equipment to a network device via a mobile communication network which is applicable to devices that must be always reachable while saving bandwidth of the mobile communication network.
It is a further objective of the present invention to provide a method and a system for connecting a user equipment to a network device via a mobile communication network, which is cost effective, which may be performed and/or operated with a reduced overall energy consumption and which requires few changes in conventional methods and systems.
In accordance with the invention, the aforementioned objectives are accomplished by a method and a system as recited by the claims and described in detail below.
According to the invention claimed, the method is characterized in that the user equipment is formed such to provide a passive state as connectivity state, wherein the user equipment in the passive state is at least page-able by an entity of the mobile communication network and that, if the user equipment is in the passive state, the user equipment is switched according to step b) after performing step a) and that at least information of a current tracking area and the, preferably unique, identifier of the user equipment is stored in an entity of the mobile communication network and/or a network device and that the information is used for at least performing step a).
Further according to the invention claimed, the system is characterized in that the user equipment is formed such to provide a passive state as connectivity state, wherein the user equipment in the passive state is at least page-able by an entity of the mobile communication network and that the user equipment is formed such that, if the user equipment is in the passive state, the user equipment is switched according to step b) after performing step a) and that at least information of a current tracking area and the, preferably unique, identifier of the user equipment is stored in a network entity of the mobile communication network and/or a network device and that the information is used for at least performing step a).
According to the invention it has been first recognized that providing a passive state as connectivity state for the user's equipment allows using a plurality of different types of user equipment due to the provided reachability in the passive state.
According to the invention it has further been first recognized, that the overall energy consumption of the user equipment and the entities of the mobile communication network is reduced thus saving costs and mobile communication network resources in the mobile communication network, since for example a permanent allocation of frequencies, channels, and context state, etc. for data transmission of the user equipment by the mobile communication network is not required.
According to a preferred embodiment the, preferably unique, identifier is at least one of the IMSI identifier, IMEI identifier or an IP address. One of the advantages is, that the unique identifier in form of an IMSI identifier, i. e. meaning international mobile subscriber identity, that a user of the user equipment may be reliably identified for example by country, used network and a mobile subscriber identification number corresponding to the user. Paging with the identifier being the IMSI identifier may provide an enhanced reachability of the user equipment without causing additional load within the whole mobile communication network, because the paging area may be limited according to the location information being available to the mobile network.
According to a further preferred embodiment at least step a) is initiated by the network device, preferably in form of a machine type communication server, connected to the mobile communication network. One advantage is that the machine type communication server serves as data receiving device for the user equipment, therefore initiation of at least step a) by the network device reduces data traffic to be exchanged for coordinating paging.
According to a further preferred embodiment the user equipment is switched to the passive state after a detaching procedure from the mobile communication network. This reduces further the energy consumption of the user equipment and at the same time reachability of the user equipment is still provided. A further advantage is, that mobile communication network resources allocated for the user equipment may be released subsequently after the user equipment has transferred its predetermined data to the network device.
According to a further preferred embodiment the user equipment remains in the passive state for a predetermined period of time. This provides an effective use of energy consumed by the user equipment avoiding that subsequent paging initiates a switching from the passive state to a deregistered state and further to initiate an attaching procedure for the mobile communication network. Thus unnecessary switching to a more active operational state of the user equipment is avoided. This also avoids an unnecessary allocation of mobile communication network resources.
According to the further preferred embodiment the user equipment is stationary or of low mobility. This means that the user equipment is stationary or at least very localized: For example the user equipment is restricted to a home or certain local area. In general the user equipment is located such, that for example the user equipment does not move outside of a coverage area of a base station of a mobile communication network. This provides a reliable connection of the user equipment to the mobile communication network.
According to a further preferred embodiment a user and/or control plane connection is initiated by the network device, preferably in form of a machine-type-communication server. This provides a simple initiation of a user and/or control plane connection when needed, for example if an application running on the network device requires retrieving data from the user equipment. In particular if the connection is initiated by the machine-type-communication server, the machine type communication server acts as authoritative source for example knowing the location of the machine type communication device which may be exactly known or at least estimated with a predetermined accuracy providing a fast connection establishment with the user equipment.
According to a further preferred embodiment for establishing the user and/or control plane connection a new connection via a new interface between at least one mobility management entity of the mobile communication network and the network device, preferably in form of a machine type communication server, is provided. This provides a direct and therefore fast connection establishment between at least one mobility management entity in the mobile communication network and the network device, preferably in form of a machine type communication server. A further advantage of this new connection via the new interface is, that traffic within the mobile communication network for establishing the user and/or control plane connection is reduced.
According to a further preferred embodiment the new connection is used for at least initiating step a). Since for example according to the network trigged service request procedure in 3GPP TS 23.401 as of 29 Sep. 2010 a mobility management entity of the mobile communication network is used for paging, a complicated adaption to other paging techniques using different mobile communication network entities or devices are not necessary by allowing a connection between the entity which initiates paging and the entity performing paging.
According to a further preferred embodiment tracking area information are included and transmitted via the new connection for initiating step a). This enhances the paging process, since a tracking area of the user equipment to be paged is included in the corresponding paging signal, so a time consuming paging of user equipment in unknown tracking areas, is not necessary.
According to a further preferred embodiment the network device, preferably in form of a machine type communication server, allocates an IP-address of the user equipment in a passive state. This provides a fast and reliable reconnection of the user equipment and the network device via the mobile communication network since a time consuming new assignment of an IP-address to the user equipment by a mobile communication network entity is not necessary. The allocated IP-address can be easily be assigned to the user equipment when being in the registered state for data communication.
According to a further preferred embodiment the mobile communication network is cell-based and the user equipment is camped on a cell. Therefore one of the advantages is, that the location information of the user equipment being camped on a certain cell of the mobile communication network only has to be transmitted once when registering the user equipment with the mobile communication network for the first time, like in a self-provisioning process. In the future this information may be already stored and is available in the mobile communication network enhancing the attaching and registration process of the user equipment with the mobile communication network even more.
BRIEF DESCRIPTION OF THE DRAWINGS
There are several ways how to design and further develop the teaching of the present invention in an advantageous way. To this end, it is to be referred to the patent claims subordinate to patent claims 1 and 13 on the one hand, and to the following explanation of preferred examples of embodiments of the invention, illustrated by the drawing on the other hand. In connection with the explanation of preferred embodiments of the invention by the aid of the drawing, generally preferred embodiments and further developments of the teaching will be explained. In the drawing
FIG. 1 is illustrating conventional state switching of a user equipment registering with a mobile communication network;
FIG. 2 is illustrating state switching of a user equipment registering with the mobile communication network by a method according to a first embodiment of the present invention;
FIG. 3 is illustrating a system according to a second embodiment of the present invention;
FIG. 4 is illustrating a state switching of a machine type communication server by a method according to a third embodiment of the present invention and
FIG. 5 is illustrating a registering and deregistering of a user equipment by a method according to a fourth embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is illustrating conventional state switching of a user equipment registering with a mobile communication network.
In FIG. 1 there are shown conventional state transitions in a current 3GPP model of the user equipment. When the user equipment is switched on (reference sign 72 ) the user equipment is first in a deregistered state B. When the user equipment is in the deregistered state B an attachment procedure for registering the user equipment with a mobile communication network is initiated (reference sign 70 a ). If the attachment procedure with a mobile communication network is successful, the user equipment switches from the deregistered state B to the registered state C. In the registered state C, which is a so-called normal state suitable for data transmission, the user equipment may perform tracking area updates, service requests or other messages via the mobile communication network. If for example a tracking area update has failed, the user equipment may be detached from the mobile communication network and switch from the registered state C to the deregistered state B.
FIG. 2 is illustrating state switching of a user equipment registering with a mobile communication network by a method according to a first embodiment of the present invention.
In contrast to FIG. 1 the deregistered state B of the user equipment comprises now two substates, a passive state B 1 and the conventional or normal deregistered state B 2 . It is further assumed that the user equipment is camped on a cell. When the user equipment is switched on (reference sign 72 ) the user equipment first enters the passive substate B 1 . When a paging and/or connection request is received by the user equipment or initiated by the user equipment itself, for example via a timer or the like the user equipment switches from the passive substate B 1 to the deregistered substate B 2 (reference sign 71 a ). In the deregistered substate B 2 of the deregistered state B the user equipment then tries to attach to the mobile communication network (reference sign 70 a ). If attaching of a user equipment is successful, the user equipment is switched from the deregistered state B in the deregistered substate B 2 to the registered state C. In the registered state C the tracking area updates, service request messages and other messages may be transmitted to and/or via the mobile communication network to a corresponding destination, for example the network device.
If for example a tracking area update fails, the user equipment may be automatically detached (reference sign 70 b ) from the mobile communication network thus entering deregistered substate B 2 of deregistered state B. In the deregistered substate B 2 the user equipment may further automatically switch to passive substate B 1 in particular for example for energy saving. That means that an establishment of connectivity and all necessary state handling and state switching is only done when needed, either by the user equipment itself or by a external trigger, in particular a paging request from the network device, preferably the machine type communication server via the mobile communication network in case of a terminating traffic triggering. The user equipment then switches its operational state from the passive substate B 1 to the deregistered substate B 2 in order to initiate the regular attach procedure to attach the user equipment to the mobile communication network. The passive state B 1 as described here explicitly could also be included as an extension within the deregistered state B.
FIG. 3 is illustrating a system according to a second embodiment of the present invention.
In FIG. 3 there is shown a system comprising a machine type communication user equipment 1 and a mobile communication network, comprising a radio access network 2 , a serving gateway 3 , a mobility management entity enhanced or designed for machine type communication 4 , a packet data network gateway 5 , and a home subscriber server 7 . The machine type communication user equipment 1 is connected to the radio access network 2 via a wireless connection 50 . The radio access network 2 is connected via a connection 51 to the serving gateway 3 . The serving gateway 3 is connected via a S 5 /S 8 interface to a packet data network gateway 5 . The serving gateway 3 is further connected via an interface S 11 with a connection 55 to the mobility management entity 4 , enhanced or designed for machine type communication. The mobility management entity 4 enhanced or designed for machine type communication is connected to the home subscriber server 7 via a connection 56 . The packet data network gateway 5 is further connected to a machine type communication server 6 via a machine type communication interface MTCi serving as a data gateway between the mobile communication network and an external network comprising the machine type communication server 6 . The machine type communication server 6 is connected via connection 54 to the mobility management entity 4 enhanced or designed for machine type communication via a corresponding interface MTC_C. If the machine type communication user equipment 1 is in the substate passive B 1 the current tracking area is stored either in the machine type communication server 6 or in the home subscriber server 7 . If the tracking area of the machine type communication user equipment 1 is stored in the home subscriber server 7 with an entry the machine type communication user equipment 1 with the tracking area information may be stored like a subscription property.
The binding of a tracking area to a machine type communication user equipment 1 or device within that tracking area might be determined by a first paging of machine type communication user equipment 1 . This maybe performed automatically. The connection 52 via the interface S 5 /S 8 and the connection 55 via the interface S 11 between the serving gateway 3 and the packet data network gateway 5 respectively the mobility management entity 4 enhanced for machine type communication do not need to be available since for example in an LTE/EPS mobile communication network, with this invention, no EPS bearer context is in place thus no user and/or control plane connectivity has to be provided or prepared.
In contrast to conventional techniques user and/or control plane connectivity via the interfaces S 5 , S 8 and S 11 may be established on demand by the machine type communication server 6 . The machine type communication server 6 connects to the mobility management entity 4 , enhanced or designed for machine type communication, located within the mobile communication network. Of course the machine type communication server 6 may connect to several mobility management entities 4 enhanced or designed for machine type communication within the mobile communication network. The machine type communication server 6 sends a triggering signal to the mobility management entity 4 via connection 54 via interface MTC_C instead of via connection 55 via interface S 11 of serving gateway 3 and via connection 52 via interface S 5 /S 8 from packet data network 5 . The machine type communication server 6 might include information about the tracking area of the machine type communication user equipment 1 specifying the location of the machine type communication user equipment 1 . To identify the machine type communication user equipment 1 within the mobile communication a unique identifier may be used, preferably the international mobile subscriber identity IMSI. The connection 54 via new interface MTC-C may be based on the GPRS Tunnelling Protocol (GTP-C) and used for initiating a control plane connection for paging between the serving gateway 3 and the mobility management entity 4 . However as mentioned above, since no context is in place in the mobility management entity 4 , the machine type communication server 6 must include for example the tracking area information of the machine type communication user equipment 1 . When using the GPRS Tunnelling Protocol this must be modified to include this information as well as the mobility management entity 4 to extract this information. The machine type communication server 6 may also allocate an IP address for the machine type communication user equipment 1 , although the machine type communication user equipment does not have an IP-address in the passive substate B 1 .
FIG. 4 is illustrating a state switching of a machine type communication server by a method according to a third embodiment of the present invention.
If the machine type communication server 6 does not receive or transmit data the machine type communication server 6 is in a sleep mode A 1 . To attach, register or link a machine type communication user equipment 1 to the machine type communication server 6 a provisioning procedure is performed, so that the machine type communication server 6 knows about the existence of the machine type communication user equipment 1 for later data transmission.
If for example an application running on the machine type communication server 6 in sleep mode A 1 needs data from the linked machine type communication user equipment 1 , the application issues a query 61 a for data transmission and the machine type communication server 6 enters now state A 2 defining query pending. The machine type communication server 6 waits now for information provided by the mobility management entity 4 , enhanced or designed for machine type communication, for successful registration of the machine type communication user equipment 1 with the mobile communication network. If a timeout and/or an explicit error occurs in the state A 2 the machine type communication server switches back (reference sign 61 b ) to sleep mode A 1 . If the query is successful (reference sign 62 ) the machine type communication server 6 switches to data transfer state A 3 and data transfer between the machine type communication user equipment 1 and the machine type communication server 6 is enabled. If the data transfer is completed a release for releasing or detaching the machine type communication user equipment 1 from the machine type communication server 6 is initiated (reference sign 64 ) and the machine type communication server 6 switches to state release pending A 4 . The machine type communication server 6 waits for information of a successful detaching of the machine type communication user equipment 1 of the mobility management entity 4 , enhanced or designed for machine type communication.
If the release is successful (reference sign 65 ) the machine type communication server 6 switches again to sleep state A 1 . If the release was not successful a retry may be initiated from the data transfer state A 3 . A data transfer may also be deactivated (reference sign 63 ) by the mobility management entity 4 causing directly the switching of the state of the machine type communication server 6 from data transfer state A 3 to sleep state A 1 . A reason for a mobility management entity initiated deactivation may be a withdrawal of the subscription of the machine type communication user equipment 1 by the home subscriber server 7 , an overload procedure handling by the mobility management entity 4 , enhanced or designed for machine type communication and/or maintenance activity at the mobility management entity 4 , enhanced or designed for machine type communication.
FIG. 5 is illustrating a registering and deregistering of a user equipment by a method according to a fourth embodiment of the present invention.
In FIG. 5 a method for establishing a connectivity setup between a machine type communication user equipment and a machine type communication server 6 via a mobile communication network is shown. The machine type communication user equipment 1 is in the beginning in the passive substate B 1 . The location information, preferably the tracking area information for paging as well as the user equipment identity is stored in the machine type communication server 6 . In a first step S 1 the machine type communication server 6 sends an activation signal, requesting establishment of connectivity and a current state of the user equipment, to the mobility management entity 4 , enhanced or designed for machine type communication. This activation signal includes the user equipment identity and tracking area information. The machine type communication user equipment identity for example IMSI, IMEI or an IP-address if statically provisioned may be included in the request. Since the machine type communication user equipment 1 is not registered, i.e. camping in a cell of the mobile communication network in the substate B 1 , the mobility management entity 4 , enhanced or designed for machine type communication, downloads in a second step S 2 a subscriber profile, indicating the machine type communication subscription with subscripted features for the machine type communication user equipment 1 . If for example other user equipment identities instead of IMSI are used for retrieving the subscriber profile from the home subscriber server 7 further enhancement in a mobility management entity-home subscriber server signalling is required. Also further identities may be relevant for the machine type communication, for example a group identity or the like.
After downloading subscription information from the home subscriber server 7 the mobility management entity 4 , enhanced or designed for machine type communication checks in a third step S 3 the downloaded subscription information and determines a corresponding tracking area for paging. A tracking area information, where the machine type communication user equipment in form of a machine type communication device resides is available in the subscriber profile of the downloaded subscription information or indicated or included as mentioned above in the activation signal from the machine type communication server 6 . The mobility management entity 4 , enhanced or designed for machine type communication, then pages in a fourth step S 4 the machine type communication user equipment 1 according to conventional steps preferably according to the network trigger service request procedure according to 3GPP TS 23.401 as of 29 Sep. 2010 preferably according to FIG. 5.3.4.3-1. The machine type communication user equipment 1 receives the sent-out paging signal respectively gets triggered by the paging signal and switches into the deregistered state B 2 from the passive substate B 1 . This results in initiating an initial attach procedure in a fifth step S 5 according, preferably to the attach procedure of 3GPP TS 23.401 as of 29 Sep. 2010, preferably in particular according to FIG. 5.3.2.1-1. The machine type communication user equipment 1 switches now to the registered state C, when the attach procedure was successful. In a sixth step S 6 the mobility management entity 4 , enhanced or designed for machine type communication, acknowledges the paging request of the machine type communication user equipment 1 to the machine type communication server 6 , including the machine type communication user equipment identity and a corresponding success report. In a seventh step S 7 the machine type communication user equipment 1 now transfers data via an evolved node B 2 a and via the serving gateway 3 and the packet data network gateway 5 to the machine type communication server 6 . Since the machine type communication user equipment 1 is an attached respectively registered state further data transfers may be effected and/or the machine type communication user equipment 1 may fall into an idle state in an eighth step S 8 .
After completion of the data transmission the machine type communication server 6 initiates a deactivation or detaching request of the machine type communication user equipment 1 towards the machine type communication server 6 in a ninth step S 9 wherein the deactivation request may include in particular the machine type communication user equipment identity and a reason for deactivation, for example completeness of the data transfer. This deactivation request is sent by the machine type communication server 6 to the mobility management entity 4 , enhanced or designed for machine type communication. The mobility management entity 4 , enhanced or designed for machine type communication performs in a tenth step S 10 the mobility-management-entity-initiated detach procedure according to 3GPP TS 23.401 as of 29 Sep. 2010, preferably according to FIG. 5.3.8.3-1.
After a successful detachment of the machine type communication user equipment 1 the mobility management entity 4 , enhanced or designed for machine type communication, acknowledges in an eleventh step S 11 the successful detachment of the machine type communication user equipment 1 to the machine type communication server 6 , including the machine type communication user equipment identity and a corresponding success report. A deactivation may also be initiated by the mobility management entity 4 , enhanced or designed for machine type communication itself.
The machine type communication user equipment 1 according to one of the FIGS. 1 to 5 must be pageable. In 3GPP TS 23.122 as of 28 Sep. 2010, subclause 4.7 a user equipment 1 or mobile station is required to listen to all paging messages that could address it according to 3GPP TS 45.002 as of 1 Oct. 2010, when the following conditions are all satisfied: A SIM is inserted, the mobile station is camped on a cell, the mobile station is not in a state “idle, no IMSI” and the mobile station is not performing the task to search for available public land mobile networks.
According to 3GPP TS 23.122 as of 28 Sep. 2010, subclause 4 . 7 conditions apply for the deregistered state B of a user equipment. Since it can be deduced from 3GPP TS 24.301 as of 28 Sep. 2010 that an initial attach procedure shall be initiated when receiving a paging signal. The paging signal in this connection of the user equipment has to be based on the IMSI identifier since by definition no context with S-temporary mobile subscriber identity S-TMSI is available. However since IMSI paging is considered as an error recovery mechanism a legacy user equipment should spend almost no time in this state. According to the required behaviour according to 3GPP TS 24.301 as of 28 Sep. 2010 an attach procedure anyway has to be performed. The machine type communication user equipment 1 may choose to remain in the passive state B 1 however for an extended period of time and the machine type communication user equipment 1 may be paged by the IMSI identifier regularly, i. e. not for error recovery. Since paging by the IMSI-identifier is preferably not applied network wide here, this does not cause any load problems in the mobile communication network.
Preferably the machine type communication user equipment may be camped on a cell, so that only a latency of the initial attach procedure remains resulting in tolerating slight delays in the order of seconds for the communication when registering the machine type communication user equipment with the mobile communication network.
In summary the present invention provides instead of “always-on/always attached”, the “almost never on/never attached” paradigm saving mobile communication network resources and at least machine type communication user equipment power consumption. The present invention provides further an intermediate state for machine type communication user equipment, called passive state, enabling the machine type communication user equipment of being page-able but not attached to the mobile communication network.
Further a control plane interface between the mobile communication network and the machine type communication user equipment is provided. Even further in the passive state of the machine type communication user equipment a storing of a location associated with the machine type communication user equipment identifier on the granularity of the different tracking areas is provided.
Preferably the machine type communication user equipment is kept in detached respectively in the passive state most of the time. In this state the machine type communication user equipment remains passive, until an outgoing or incoming traffic has to be handled. However, the machine type communication user equipment in the passive state reads mobile communication network information preferably in broadcast messages. Except for location information, preferably stored in a subscription property in the home subscriber server, no active or dynamic state for the machine type communication user equipment needs to be stored in an entity of the mobile communication network. This leads to a reduction of signalling with and within the mobile communication network in contrast to machine type communication user equipment in a registered state and/or idle registered state. By exhibiting the control plane interface towards the mobile communication network this enables externally triggered paging for machine type communication user equipment resulting in optimizations for machine type communication devices and data traffic between the machine type communication user equipment and a mobile communication network and/or a network device.
Further advantages of the present invention are that unnecessary idle mode signalling between the machine type communication user equipment and the mobile communication network and/or the network device is avoided. Further dynamic state information traffic within the mobile communication network and/or with the machine type communication user equipment and/or the network device is significantly reduced. Even further a power consumption of machine type communication user equipment and corresponding mobile communication network devices is reduced. The present invention may also be easily be implemented and used on user equipment concerning machine type communication, for example consumption metering, non real-time data acquisition, counters, inventory reporting or the like, meaning devices which send or receive data infrequently, preferably having communication intervals separated in the order of days.
Many modifications and other embodiments of the invention set forth herein will come to mind the one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing description and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. | A method for connecting a user equipment to a network device via a mobile communication network, applicable to devices that must always be reachable while saving bandwidth of the mobile communication network, where the user equipment operates in a passive state capable of responding to a page signal by switching to an attempting-to-attach state, and at least an information of a current tracking area and an identifier of the user equipment is stored in an entity of the mobile communication network and/or a network device, this information being used for sending the paging signal to the equipment. | Identify and summarize the most critical technical features from the given patent document. | [
"BACKGROUND OF THE INVENTION The invention relates to a method for connecting a user equipment to a network device via a mobile communication network wherein the user equipment comprises at least a deregistered state and a registered state, wherein the deregistered state comprises at least two substates, a normal and an attempting-to-attach substate, for defining a connectivity state of the user equipment to the mobile communication network, and wherein the user equipment is connectable to the mobile communication network and wherein the network device is connected to the mobile communication network comprising the steps of a) Paging of the user equipment by a paging signal using a, preferably unique, user equipment identifier, b) Switching to the attempting-to-attach substate of the deregistered state of the user equipment when receiving a paging signal, c) Attaching the user equipment to the mobile communication network, and d) Switching to the registered state of the user equipment depending on a result of the attachment according to step c).",
"The present invention also relates to a system for connecting a user equipment to a network device via a mobile communication network, wherein the user equipment is formed such to provide at least a deregistered state and a registered state, wherein the deregistered state comprises at least two substates, a normal and an attempting-to-attach substate, for defining a connectivity state of the user equipment to the mobile communication network, and wherein the user equipment is connectable to the mobile communication network and wherein the network device is connected to the mobile communication network, and wherein the user equipment is formed such that on receiving a paging signal due to paging using a, preferably unique, user equipment identifier, the user equipment switches to the attempting-to-attach substate of the deregistered state of the user equipment, attaches to the mobile communication network, and switches to the registered state of the user equipment depending on a result of the attachment according to step c).",
"Conventional connecting techniques in mobile communication networks, for example a cell phone connecting to a base station of a UMTS mobile communication network and further for example via the UMTS mobile communication network and the internet to a dedicated server, like an email server, have been mainly designed to be used by human beings.",
"Conventional states of a user equipment, also named mobile terminal or mobile station, comprises therefore in general two operational states in particular regarding registration, namely a deregistered state and a registered state.",
"In addition, in registered state the user equipment can be in two different modes regarding its connection, namely an EMM-connected or an EMM-idle state.",
"When a signalling connection is established the user equipment may be in the registered state in normal-service substate and in a further, additional substate EMM-connected.",
"If a NAS signalling connection is not established the user equipment may be in a substate EMM-idle.",
"When the user equipment is in the registered state, the user equipment may transmit data to respectively via the mobile communication network to a dedicated server for example in the internet.",
"In the deregistered state the user equipment may be in normal substate or in attempting-to-attach state.",
"In the normal deregistered substate the user equipment cannot transmit or receive data but may be able to initiate an attach or a combined attached procedure.",
"For initiating an attach or combined attached procedure the user equipment switches in the deregistered state to an attempting-to-attach substate initiating an attach.",
"When the attach to the mobile communication network is successful the user equipment becomes registered in the mobile communication network and switches to the registered state allowing the transfer of data between the user equipment and the dedicated server.",
"In this normal-service registered state the user equipment may transmit data which, if the user equipment is in EMM-idle, may be initiated by a Service Request NAS signalling message.",
"FIG. 1 shows a conventional switching of states of a user equipment in a current 3GPP model.",
"When the user equipment is switched on (reference sign 72 ) the user equipment is first in a deregistered state B. After switching on 72 the user equipment likes to become attached to a mobile communication network and therefore tries to register with the mobile communication network as soon as possible.",
"After a successful attach (reference sign 70 a ) the user equipment switches from the deregistered state B to a registered state C. The user equipment also remains registered, i. e. in the normal-service substate, as long as no error condition or restriction from the mobile communication network occurs.",
"The registration is prerequisite to reachability of the user equipment which may be defined via paging based on tracking area information stored in a mobile communication network entity, preferably a mobility management entity and the tracking area information depends on location registration of the user equipment.",
"However, for new classes of devices, in particular machine type communication devices, conventional registration techniques have a number of drawbacks.",
"For example if a machine type communication device is fixed in a location and scheduled to deliver data once every month via the mobile communication network this would cause costs due to a high energy consumption of the user equipment for being and staying registered in the mobile communication network.",
"Another drawback is that the registration of the machine type communication device creates a signalling overhead and shortens the bandwidth for other especially none-machine-type-communication devices in the mobile communication network.",
"In the registered state the user equipment has to be permanently staying in the necessary context state for example security context, location context, bearer context, etc.",
"To overcome these drawbacks the user equipment may be switched on and/or off at appropriate times: The user equipment may be switched on for example when an uplink communication, i. e. from the user equipment to the mobile communication network, is necessary: The user equipment then attaches and registers to the mobile communication network and all necessary context is created subsequently.",
"Switching on and off may be handled by local environment devices of the user equipment, for example the user equipment may be communicating with or connected to a timer, counter thresholds, sensors or the like.",
"Another option to overcome these drawbacks is the use of well-defined time slots for a communication, in particular for the registration process, of the user equipment with the mobile communication network.",
"These time slots are fixed and known to the user equipment and to a predefined entity of the mobile communication network handling the establishment of the connection.",
"This may be implemented for example by attaching the user equipment to a timer device which activates or deactivates the user equipment power switch sufficiently before and after the defined time slots.",
"In order to obtain a reliable bidirectional connection between the user equipment and the mobile communication network the local time of the mobile communication network and the user equipment must be well synchronized.",
"However this solution has inter alia one main disadvantage: This solution may not be applicable to devices which need to be reachable at all times, since by turning off the user equipment the user equipment is deregistered and is not able to receive any communication signals from the mobile communication network.",
"SUMMARY OF THE INVENTION It is therefore an objective of the present invention to provide a method and a system method for connecting a user equipment to a network device via a mobile communication network which is applicable to devices that must be always reachable while saving bandwidth of the mobile communication network.",
"It is a further objective of the present invention to provide a method and a system for connecting a user equipment to a network device via a mobile communication network, which is cost effective, which may be performed and/or operated with a reduced overall energy consumption and which requires few changes in conventional methods and systems.",
"In accordance with the invention, the aforementioned objectives are accomplished by a method and a system as recited by the claims and described in detail below.",
"According to the invention claimed, the method is characterized in that the user equipment is formed such to provide a passive state as connectivity state, wherein the user equipment in the passive state is at least page-able by an entity of the mobile communication network and that, if the user equipment is in the passive state, the user equipment is switched according to step b) after performing step a) and that at least information of a current tracking area and the, preferably unique, identifier of the user equipment is stored in an entity of the mobile communication network and/or a network device and that the information is used for at least performing step a).",
"Further according to the invention claimed, the system is characterized in that the user equipment is formed such to provide a passive state as connectivity state, wherein the user equipment in the passive state is at least page-able by an entity of the mobile communication network and that the user equipment is formed such that, if the user equipment is in the passive state, the user equipment is switched according to step b) after performing step a) and that at least information of a current tracking area and the, preferably unique, identifier of the user equipment is stored in a network entity of the mobile communication network and/or a network device and that the information is used for at least performing step a).",
"According to the invention it has been first recognized that providing a passive state as connectivity state for the user's equipment allows using a plurality of different types of user equipment due to the provided reachability in the passive state.",
"According to the invention it has further been first recognized, that the overall energy consumption of the user equipment and the entities of the mobile communication network is reduced thus saving costs and mobile communication network resources in the mobile communication network, since for example a permanent allocation of frequencies, channels, and context state, etc.",
"for data transmission of the user equipment by the mobile communication network is not required.",
"According to a preferred embodiment the, preferably unique, identifier is at least one of the IMSI identifier, IMEI identifier or an IP address.",
"One of the advantages is, that the unique identifier in form of an IMSI identifier, i. e. meaning international mobile subscriber identity, that a user of the user equipment may be reliably identified for example by country, used network and a mobile subscriber identification number corresponding to the user.",
"Paging with the identifier being the IMSI identifier may provide an enhanced reachability of the user equipment without causing additional load within the whole mobile communication network, because the paging area may be limited according to the location information being available to the mobile network.",
"According to a further preferred embodiment at least step a) is initiated by the network device, preferably in form of a machine type communication server, connected to the mobile communication network.",
"One advantage is that the machine type communication server serves as data receiving device for the user equipment, therefore initiation of at least step a) by the network device reduces data traffic to be exchanged for coordinating paging.",
"According to a further preferred embodiment the user equipment is switched to the passive state after a detaching procedure from the mobile communication network.",
"This reduces further the energy consumption of the user equipment and at the same time reachability of the user equipment is still provided.",
"A further advantage is, that mobile communication network resources allocated for the user equipment may be released subsequently after the user equipment has transferred its predetermined data to the network device.",
"According to a further preferred embodiment the user equipment remains in the passive state for a predetermined period of time.",
"This provides an effective use of energy consumed by the user equipment avoiding that subsequent paging initiates a switching from the passive state to a deregistered state and further to initiate an attaching procedure for the mobile communication network.",
"Thus unnecessary switching to a more active operational state of the user equipment is avoided.",
"This also avoids an unnecessary allocation of mobile communication network resources.",
"According to the further preferred embodiment the user equipment is stationary or of low mobility.",
"This means that the user equipment is stationary or at least very localized: For example the user equipment is restricted to a home or certain local area.",
"In general the user equipment is located such, that for example the user equipment does not move outside of a coverage area of a base station of a mobile communication network.",
"This provides a reliable connection of the user equipment to the mobile communication network.",
"According to a further preferred embodiment a user and/or control plane connection is initiated by the network device, preferably in form of a machine-type-communication server.",
"This provides a simple initiation of a user and/or control plane connection when needed, for example if an application running on the network device requires retrieving data from the user equipment.",
"In particular if the connection is initiated by the machine-type-communication server, the machine type communication server acts as authoritative source for example knowing the location of the machine type communication device which may be exactly known or at least estimated with a predetermined accuracy providing a fast connection establishment with the user equipment.",
"According to a further preferred embodiment for establishing the user and/or control plane connection a new connection via a new interface between at least one mobility management entity of the mobile communication network and the network device, preferably in form of a machine type communication server, is provided.",
"This provides a direct and therefore fast connection establishment between at least one mobility management entity in the mobile communication network and the network device, preferably in form of a machine type communication server.",
"A further advantage of this new connection via the new interface is, that traffic within the mobile communication network for establishing the user and/or control plane connection is reduced.",
"According to a further preferred embodiment the new connection is used for at least initiating step a).",
"Since for example according to the network trigged service request procedure in 3GPP TS 23.401 as of 29 Sep. 2010 a mobility management entity of the mobile communication network is used for paging, a complicated adaption to other paging techniques using different mobile communication network entities or devices are not necessary by allowing a connection between the entity which initiates paging and the entity performing paging.",
"According to a further preferred embodiment tracking area information are included and transmitted via the new connection for initiating step a).",
"This enhances the paging process, since a tracking area of the user equipment to be paged is included in the corresponding paging signal, so a time consuming paging of user equipment in unknown tracking areas, is not necessary.",
"According to a further preferred embodiment the network device, preferably in form of a machine type communication server, allocates an IP-address of the user equipment in a passive state.",
"This provides a fast and reliable reconnection of the user equipment and the network device via the mobile communication network since a time consuming new assignment of an IP-address to the user equipment by a mobile communication network entity is not necessary.",
"The allocated IP-address can be easily be assigned to the user equipment when being in the registered state for data communication.",
"According to a further preferred embodiment the mobile communication network is cell-based and the user equipment is camped on a cell.",
"Therefore one of the advantages is, that the location information of the user equipment being camped on a certain cell of the mobile communication network only has to be transmitted once when registering the user equipment with the mobile communication network for the first time, like in a self-provisioning process.",
"In the future this information may be already stored and is available in the mobile communication network enhancing the attaching and registration process of the user equipment with the mobile communication network even more.",
"BRIEF DESCRIPTION OF THE DRAWINGS There are several ways how to design and further develop the teaching of the present invention in an advantageous way.",
"To this end, it is to be referred to the patent claims subordinate to patent claims 1 and 13 on the one hand, and to the following explanation of preferred examples of embodiments of the invention, illustrated by the drawing on the other hand.",
"In connection with the explanation of preferred embodiments of the invention by the aid of the drawing, generally preferred embodiments and further developments of the teaching will be explained.",
"In the drawing FIG. 1 is illustrating conventional state switching of a user equipment registering with a mobile communication network;",
"FIG. 2 is illustrating state switching of a user equipment registering with the mobile communication network by a method according to a first embodiment of the present invention;",
"FIG. 3 is illustrating a system according to a second embodiment of the present invention;",
"FIG. 4 is illustrating a state switching of a machine type communication server by a method according to a third embodiment of the present invention and FIG. 5 is illustrating a registering and deregistering of a user equipment by a method according to a fourth embodiment of the present invention.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is illustrating conventional state switching of a user equipment registering with a mobile communication network.",
"In FIG. 1 there are shown conventional state transitions in a current 3GPP model of the user equipment.",
"When the user equipment is switched on (reference sign 72 ) the user equipment is first in a deregistered state B. When the user equipment is in the deregistered state B an attachment procedure for registering the user equipment with a mobile communication network is initiated (reference sign 70 a ).",
"If the attachment procedure with a mobile communication network is successful, the user equipment switches from the deregistered state B to the registered state C. In the registered state C, which is a so-called normal state suitable for data transmission, the user equipment may perform tracking area updates, service requests or other messages via the mobile communication network.",
"If for example a tracking area update has failed, the user equipment may be detached from the mobile communication network and switch from the registered state C to the deregistered state B. FIG. 2 is illustrating state switching of a user equipment registering with a mobile communication network by a method according to a first embodiment of the present invention.",
"In contrast to FIG. 1 the deregistered state B of the user equipment comprises now two substates, a passive state B 1 and the conventional or normal deregistered state B 2 .",
"It is further assumed that the user equipment is camped on a cell.",
"When the user equipment is switched on (reference sign 72 ) the user equipment first enters the passive substate B 1 .",
"When a paging and/or connection request is received by the user equipment or initiated by the user equipment itself, for example via a timer or the like the user equipment switches from the passive substate B 1 to the deregistered substate B 2 (reference sign 71 a ).",
"In the deregistered substate B 2 of the deregistered state B the user equipment then tries to attach to the mobile communication network (reference sign 70 a ).",
"If attaching of a user equipment is successful, the user equipment is switched from the deregistered state B in the deregistered substate B 2 to the registered state C. In the registered state C the tracking area updates, service request messages and other messages may be transmitted to and/or via the mobile communication network to a corresponding destination, for example the network device.",
"If for example a tracking area update fails, the user equipment may be automatically detached (reference sign 70 b ) from the mobile communication network thus entering deregistered substate B 2 of deregistered state B. In the deregistered substate B 2 the user equipment may further automatically switch to passive substate B 1 in particular for example for energy saving.",
"That means that an establishment of connectivity and all necessary state handling and state switching is only done when needed, either by the user equipment itself or by a external trigger, in particular a paging request from the network device, preferably the machine type communication server via the mobile communication network in case of a terminating traffic triggering.",
"The user equipment then switches its operational state from the passive substate B 1 to the deregistered substate B 2 in order to initiate the regular attach procedure to attach the user equipment to the mobile communication network.",
"The passive state B 1 as described here explicitly could also be included as an extension within the deregistered state B. FIG. 3 is illustrating a system according to a second embodiment of the present invention.",
"In FIG. 3 there is shown a system comprising a machine type communication user equipment 1 and a mobile communication network, comprising a radio access network 2 , a serving gateway 3 , a mobility management entity enhanced or designed for machine type communication 4 , a packet data network gateway 5 , and a home subscriber server 7 .",
"The machine type communication user equipment 1 is connected to the radio access network 2 via a wireless connection 50 .",
"The radio access network 2 is connected via a connection 51 to the serving gateway 3 .",
"The serving gateway 3 is connected via a S 5 /S 8 interface to a packet data network gateway 5 .",
"The serving gateway 3 is further connected via an interface S 11 with a connection 55 to the mobility management entity 4 , enhanced or designed for machine type communication.",
"The mobility management entity 4 enhanced or designed for machine type communication is connected to the home subscriber server 7 via a connection 56 .",
"The packet data network gateway 5 is further connected to a machine type communication server 6 via a machine type communication interface MTCi serving as a data gateway between the mobile communication network and an external network comprising the machine type communication server 6 .",
"The machine type communication server 6 is connected via connection 54 to the mobility management entity 4 enhanced or designed for machine type communication via a corresponding interface MTC_C.",
"If the machine type communication user equipment 1 is in the substate passive B 1 the current tracking area is stored either in the machine type communication server 6 or in the home subscriber server 7 .",
"If the tracking area of the machine type communication user equipment 1 is stored in the home subscriber server 7 with an entry the machine type communication user equipment 1 with the tracking area information may be stored like a subscription property.",
"The binding of a tracking area to a machine type communication user equipment 1 or device within that tracking area might be determined by a first paging of machine type communication user equipment 1 .",
"This maybe performed automatically.",
"The connection 52 via the interface S 5 /S 8 and the connection 55 via the interface S 11 between the serving gateway 3 and the packet data network gateway 5 respectively the mobility management entity 4 enhanced for machine type communication do not need to be available since for example in an LTE/EPS mobile communication network, with this invention, no EPS bearer context is in place thus no user and/or control plane connectivity has to be provided or prepared.",
"In contrast to conventional techniques user and/or control plane connectivity via the interfaces S 5 , S 8 and S 11 may be established on demand by the machine type communication server 6 .",
"The machine type communication server 6 connects to the mobility management entity 4 , enhanced or designed for machine type communication, located within the mobile communication network.",
"Of course the machine type communication server 6 may connect to several mobility management entities 4 enhanced or designed for machine type communication within the mobile communication network.",
"The machine type communication server 6 sends a triggering signal to the mobility management entity 4 via connection 54 via interface MTC_C instead of via connection 55 via interface S 11 of serving gateway 3 and via connection 52 via interface S 5 /S 8 from packet data network 5 .",
"The machine type communication server 6 might include information about the tracking area of the machine type communication user equipment 1 specifying the location of the machine type communication user equipment 1 .",
"To identify the machine type communication user equipment 1 within the mobile communication a unique identifier may be used, preferably the international mobile subscriber identity IMSI.",
"The connection 54 via new interface MTC-C may be based on the GPRS Tunnelling Protocol (GTP-C) and used for initiating a control plane connection for paging between the serving gateway 3 and the mobility management entity 4 .",
"However as mentioned above, since no context is in place in the mobility management entity 4 , the machine type communication server 6 must include for example the tracking area information of the machine type communication user equipment 1 .",
"When using the GPRS Tunnelling Protocol this must be modified to include this information as well as the mobility management entity 4 to extract this information.",
"The machine type communication server 6 may also allocate an IP address for the machine type communication user equipment 1 , although the machine type communication user equipment does not have an IP-address in the passive substate B 1 .",
"FIG. 4 is illustrating a state switching of a machine type communication server by a method according to a third embodiment of the present invention.",
"If the machine type communication server 6 does not receive or transmit data the machine type communication server 6 is in a sleep mode A 1 .",
"To attach, register or link a machine type communication user equipment 1 to the machine type communication server 6 a provisioning procedure is performed, so that the machine type communication server 6 knows about the existence of the machine type communication user equipment 1 for later data transmission.",
"If for example an application running on the machine type communication server 6 in sleep mode A 1 needs data from the linked machine type communication user equipment 1 , the application issues a query 61 a for data transmission and the machine type communication server 6 enters now state A 2 defining query pending.",
"The machine type communication server 6 waits now for information provided by the mobility management entity 4 , enhanced or designed for machine type communication, for successful registration of the machine type communication user equipment 1 with the mobile communication network.",
"If a timeout and/or an explicit error occurs in the state A 2 the machine type communication server switches back (reference sign 61 b ) to sleep mode A 1 .",
"If the query is successful (reference sign 62 ) the machine type communication server 6 switches to data transfer state A 3 and data transfer between the machine type communication user equipment 1 and the machine type communication server 6 is enabled.",
"If the data transfer is completed a release for releasing or detaching the machine type communication user equipment 1 from the machine type communication server 6 is initiated (reference sign 64 ) and the machine type communication server 6 switches to state release pending A 4 .",
"The machine type communication server 6 waits for information of a successful detaching of the machine type communication user equipment 1 of the mobility management entity 4 , enhanced or designed for machine type communication.",
"If the release is successful (reference sign 65 ) the machine type communication server 6 switches again to sleep state A 1 .",
"If the release was not successful a retry may be initiated from the data transfer state A 3 .",
"A data transfer may also be deactivated (reference sign 63 ) by the mobility management entity 4 causing directly the switching of the state of the machine type communication server 6 from data transfer state A 3 to sleep state A 1 .",
"A reason for a mobility management entity initiated deactivation may be a withdrawal of the subscription of the machine type communication user equipment 1 by the home subscriber server 7 , an overload procedure handling by the mobility management entity 4 , enhanced or designed for machine type communication and/or maintenance activity at the mobility management entity 4 , enhanced or designed for machine type communication.",
"FIG. 5 is illustrating a registering and deregistering of a user equipment by a method according to a fourth embodiment of the present invention.",
"In FIG. 5 a method for establishing a connectivity setup between a machine type communication user equipment and a machine type communication server 6 via a mobile communication network is shown.",
"The machine type communication user equipment 1 is in the beginning in the passive substate B 1 .",
"The location information, preferably the tracking area information for paging as well as the user equipment identity is stored in the machine type communication server 6 .",
"In a first step S 1 the machine type communication server 6 sends an activation signal, requesting establishment of connectivity and a current state of the user equipment, to the mobility management entity 4 , enhanced or designed for machine type communication.",
"This activation signal includes the user equipment identity and tracking area information.",
"The machine type communication user equipment identity for example IMSI, IMEI or an IP-address if statically provisioned may be included in the request.",
"Since the machine type communication user equipment 1 is not registered, i.e. camping in a cell of the mobile communication network in the substate B 1 , the mobility management entity 4 , enhanced or designed for machine type communication, downloads in a second step S 2 a subscriber profile, indicating the machine type communication subscription with subscripted features for the machine type communication user equipment 1 .",
"If for example other user equipment identities instead of IMSI are used for retrieving the subscriber profile from the home subscriber server 7 further enhancement in a mobility management entity-home subscriber server signalling is required.",
"Also further identities may be relevant for the machine type communication, for example a group identity or the like.",
"After downloading subscription information from the home subscriber server 7 the mobility management entity 4 , enhanced or designed for machine type communication checks in a third step S 3 the downloaded subscription information and determines a corresponding tracking area for paging.",
"A tracking area information, where the machine type communication user equipment in form of a machine type communication device resides is available in the subscriber profile of the downloaded subscription information or indicated or included as mentioned above in the activation signal from the machine type communication server 6 .",
"The mobility management entity 4 , enhanced or designed for machine type communication, then pages in a fourth step S 4 the machine type communication user equipment 1 according to conventional steps preferably according to the network trigger service request procedure according to 3GPP TS 23.401 as of 29 Sep. 2010 preferably according to FIG. 5.3[.",
"].4.3-1.",
"The machine type communication user equipment 1 receives the sent-out paging signal respectively gets triggered by the paging signal and switches into the deregistered state B 2 from the passive substate B 1 .",
"This results in initiating an initial attach procedure in a fifth step S 5 according, preferably to the attach procedure of 3GPP TS 23.401 as of 29 Sep. 2010, preferably in particular according to FIG. 5.3[.",
"].2.1-1.",
"The machine type communication user equipment 1 switches now to the registered state C, when the attach procedure was successful.",
"In a sixth step S 6 the mobility management entity 4 , enhanced or designed for machine type communication, acknowledges the paging request of the machine type communication user equipment 1 to the machine type communication server 6 , including the machine type communication user equipment identity and a corresponding success report.",
"In a seventh step S 7 the machine type communication user equipment 1 now transfers data via an evolved node B 2 a and via the serving gateway 3 and the packet data network gateway 5 to the machine type communication server 6 .",
"Since the machine type communication user equipment 1 is an attached respectively registered state further data transfers may be effected and/or the machine type communication user equipment 1 may fall into an idle state in an eighth step S 8 .",
"After completion of the data transmission the machine type communication server 6 initiates a deactivation or detaching request of the machine type communication user equipment 1 towards the machine type communication server 6 in a ninth step S 9 wherein the deactivation request may include in particular the machine type communication user equipment identity and a reason for deactivation, for example completeness of the data transfer.",
"This deactivation request is sent by the machine type communication server 6 to the mobility management entity 4 , enhanced or designed for machine type communication.",
"The mobility management entity 4 , enhanced or designed for machine type communication performs in a tenth step S 10 the mobility-management-entity-initiated detach procedure according to 3GPP TS 23.401 as of 29 Sep. 2010, preferably according to FIG. 5.3[.",
"].8.3-1.",
"After a successful detachment of the machine type communication user equipment 1 the mobility management entity 4 , enhanced or designed for machine type communication, acknowledges in an eleventh step S 11 the successful detachment of the machine type communication user equipment 1 to the machine type communication server 6 , including the machine type communication user equipment identity and a corresponding success report.",
"A deactivation may also be initiated by the mobility management entity 4 , enhanced or designed for machine type communication itself.",
"The machine type communication user equipment 1 according to one of the FIGS. 1 to 5 must be pageable.",
"In 3GPP TS 23.122 as of 28 Sep. 2010, subclause 4.7 a user equipment 1 or mobile station is required to listen to all paging messages that could address it according to 3GPP TS 45.002 as of 1 Oct. 2010, when the following conditions are all satisfied: A SIM is inserted, the mobile station is camped on a cell, the mobile station is not in a state “idle, no IMSI”",
"and the mobile station is not performing the task to search for available public land mobile networks.",
"According to 3GPP TS 23.122 as of 28 Sep. 2010, subclause 4 .",
"7 conditions apply for the deregistered state B of a user equipment.",
"Since it can be deduced from 3GPP TS 24.301 as of 28 Sep. 2010 that an initial attach procedure shall be initiated when receiving a paging signal.",
"The paging signal in this connection of the user equipment has to be based on the IMSI identifier since by definition no context with S-temporary mobile subscriber identity S-TMSI is available.",
"However since IMSI paging is considered as an error recovery mechanism a legacy user equipment should spend almost no time in this state.",
"According to the required behaviour according to 3GPP TS 24.301 as of 28 Sep. 2010 an attach procedure anyway has to be performed.",
"The machine type communication user equipment 1 may choose to remain in the passive state B 1 however for an extended period of time and the machine type communication user equipment 1 may be paged by the IMSI identifier regularly, i. e. not for error recovery.",
"Since paging by the IMSI-identifier is preferably not applied network wide here, this does not cause any load problems in the mobile communication network.",
"Preferably the machine type communication user equipment may be camped on a cell, so that only a latency of the initial attach procedure remains resulting in tolerating slight delays in the order of seconds for the communication when registering the machine type communication user equipment with the mobile communication network.",
"In summary the present invention provides instead of “always-on/always attached”, the “almost never on/never attached”",
"paradigm saving mobile communication network resources and at least machine type communication user equipment power consumption.",
"The present invention provides further an intermediate state for machine type communication user equipment, called passive state, enabling the machine type communication user equipment of being page-able but not attached to the mobile communication network.",
"Further a control plane interface between the mobile communication network and the machine type communication user equipment is provided.",
"Even further in the passive state of the machine type communication user equipment a storing of a location associated with the machine type communication user equipment identifier on the granularity of the different tracking areas is provided.",
"Preferably the machine type communication user equipment is kept in detached respectively in the passive state most of the time.",
"In this state the machine type communication user equipment remains passive, until an outgoing or incoming traffic has to be handled.",
"However, the machine type communication user equipment in the passive state reads mobile communication network information preferably in broadcast messages.",
"Except for location information, preferably stored in a subscription property in the home subscriber server, no active or dynamic state for the machine type communication user equipment needs to be stored in an entity of the mobile communication network.",
"This leads to a reduction of signalling with and within the mobile communication network in contrast to machine type communication user equipment in a registered state and/or idle registered state.",
"By exhibiting the control plane interface towards the mobile communication network this enables externally triggered paging for machine type communication user equipment resulting in optimizations for machine type communication devices and data traffic between the machine type communication user equipment and a mobile communication network and/or a network device.",
"Further advantages of the present invention are that unnecessary idle mode signalling between the machine type communication user equipment and the mobile communication network and/or the network device is avoided.",
"Further dynamic state information traffic within the mobile communication network and/or with the machine type communication user equipment and/or the network device is significantly reduced.",
"Even further a power consumption of machine type communication user equipment and corresponding mobile communication network devices is reduced.",
"The present invention may also be easily be implemented and used on user equipment concerning machine type communication, for example consumption metering, non real-time data acquisition, counters, inventory reporting or the like, meaning devices which send or receive data infrequently, preferably having communication intervals separated in the order of days.",
"Many modifications and other embodiments of the invention set forth herein will come to mind the one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing description and the associated drawings.",
"Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims.",
"Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation."
] |
CROSS-REFERENCED RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Ser. No. 14/612,450 filed Feb. 3, 2015, which is a continuation of U.S. Ser. No. 12/869,362 filed Aug. 26, 2010, issued as U.S. Pat. No. 8,992,487 on Mar. 31, 2015, which is a continuation of International Patent Application No. PCT/CH2009/000078 filed Feb. 26, 2009, which claims priority to German Patent Application No. 10 2008 011 885.0 filed Feb. 29, 2008, the entire contents of each of which are incorporated herein by reference.
BACKGROUND
[0002] The present invention related to devices for injecting, infusing, administering, dispensing or delivering a substance, and to methods of making and using such devices. More particularly, the present invention relates to an injection device for administering a substance or product such as a medicament or therapeutic substance, e.g. insulin, growth hormone, etc.
[0003] The idea of coupling an ampoule (which also may be referred to and/or thought of as a container, carpoule, vial or the like) containing a product to or in an injection device is known from the prior art. Securing an ampoule in a stationary seating, for example in an ampoule holder, when attached to the injection device is also known. In some cases, the ampoule may be screwed into the holder, and the securing or holding may be achieved by a clamping action wherein the product container accommodated in the ampoule holder is clamped between the distal (forward) end of the ampoule holder and a stop which acts on the distal end of the ampoule.
SUMMARY
[0004] An object of the present invention is to provide an injection device to which a product container can be secured in a reliable, efficient and economic manner.
[0005] In one embodiment, the present invention comprises an injection device for dispensing a product, the injection device including a moveable element which is moved for a dispensing operation, a spring, a product container holder and a product container, wherein the spring pushes against the moveable element to move the moveable element to an initial position after the dispensing operation has ended and against the product container to seat the product container in the product container holder.
[0006] In one embodiment of an injection device according to the present invention, the device comprises coupling element, a product container, and a spring between the coupling element and the product container, the spring biasing or urging the coupling element in one direction and the product container in the other, i.e. opposite, direction.
[0007] In some embodiments, the present invention comprises an injection device whereby an injection may be administered manually by the user or may take place automatically. For example, a user of an embodiment of the device designed for automatically dispensing the product may operate an operating element which releases a drive element, for example a spring, and the spring force acts indirectly or directly on an output element and/or pushes the plunger of a product container in a dispensing direction. The drive element may be a motor, a pyrotechnic propellant charge or, as in some preferred embodiments of the present invention, a spring, e.g. a mechanical spring. If the drive element is of the type which stores energy, in some preferred embodiments the stored energy can be released by an operating element so that a driving movement can be converted into an output movement. In some embodiments, the driving movement may be a rotating movement, and the output movement may be a linear movement.
[0008] In some preferred embodiments, the drive element may be a rotating spring, e.g. a helical or clock spring, which is wound about the longitudinal axis of the injection device. For example, the spring may be supported in a fixed arrangement on the housing in at least one direction of rotation by one end and connected to the output element or a part which is or can be coupled with the output element by the other end. Thus, the rotational energy stored in the spring may be converted into a driving movement. In some embodiments, it is advantageous to use a strip-shaped helical spring.
[0009] In some embodiments, an injection device in accordance with the present invention may be disposable. Generally, in such embodiments, a product container inserted or built into the device during production can not be replaced, and when empty or after the injection device has been used, it is disposed of as a whole together with the product container.
[0010] In some embodiments, an injection device in accordance with the present invention is designed to be used more than once. This is practical if the injection device is fitted with high-quality and/or high-tolerance components designed to make it easy to dispense a product and which may be too expensive for use with disposable items. In some embodiments, a driving mechanism is incorporated in a drive unit, in which case the product container can be attached to the drive unit, and can be detached from the drive unit. An empty product container can be released from the drive unit, disposed of and replaced by a new one.
[0011] In some preferred embodiments, the product container is received and/or seated in a product container holder. The product container holder is sleeve-shaped and has an opening through which the product container can be inserted into the interior of the sleeve. The opening may be disposed laterally or on an end, e.g. the proximal (rear) end, of the product container holder. At the side, the product container holder may have a region through which it is possible to see from the outside into the interior of the container to, for example, ascertain whether a product container has been inserted or to check how full an inserted product container is. The product container holder may have a collar at its distal (forward) end, against which the product container sits in an abutting contact in its inserted state. The product container is then fixedly seated in the product container holder. The product container holder may have a conical shape, and the product container can be pushed into it to obtain a fixed seating.
[0012] In some preferred embodiments, an injection device in accordance with the present invention, e.g. the drive unit thereof, may comprise a spring element, such as a mechanical spring, a gas compression spring or other elastic means, which acts on or pushes on the product container, e.g. the part of the product container relative to which the plunger can be displaced. In some preferred embodiments, the spring element may push the product container into a fixed seating with and/or within the product container holder. In some preferred embodiments, the spring element may act in the longitudinal direction of the injection device.
[0013] In some embodiments of the present invention, the product container may be an ampoule or capped vial, for example, and is open at its proximal (rear) end and closed at its distal (forward or front) end. An output element of the drive unit may extend through the proximal end into the product container to act on a plunger or piston in the container, which plunger or piston can be displaced relative to the product container wall. The distal end may incorporate or carry a needle, or may be designed so that a needle can be attached, thereby establishing a flow connection to the interior of the product container due to the fact that the needle pierces a septum disposed on the distal end of the product container. In some preferred embodiments, the wall of the product container is cylindrical, and it may be tightly enclosed by the sleeve-shaped product container holder or enclosed with a slight clearance.
[0014] In some embodiments, the injection device may have an element which is moved back into an initial position after a dispensing operation has ended or as it is ending. This may be an operating element which can be operated by moving it, e.g. by moving it axially along a longitudinal axis of the injection device. The element may be moved into a dispensing position as the dispensing operation is being actuated or triggered, in which case the direction of movement needed for this purpose is opposite the direction of movement in which the element can move on terminating the dispensing operation. The operating element may be operated by a user of the device to trigger and/or stop dispensing of the product, or it may be released after the product has been dispensed whereby it moves back or automatically returns to its initial position. A lock element may be coupled with the operating element so that it is axially locked, at least in one direction and, in some preferred embodiments, in both directions.
[0015] In some embodiments, the operating element moves back or can be moved back to an initial position after the dispensing operation has terminated. Thus, an injection device in accordance with the present invention may comprise a coupling, e.g. a coupling element which establishes or releases a coupling as it is moved. For example, such a coupling element may be coupled with the operating element in at least one direction and at least for a certain time. The coupling element may push the operating element in one direction, and in the other, opposite direction, the operating element may push the coupling element.
[0016] In some preferred embodiments, the element which is moveable when a dispensing operation is terminated or triggered may be moved back into an initial position by a spring element when the dispensing operation has terminated. The spring element may also urge the product container into its fixed seating. In some preferred embodiments, the spring element is a helical spring, which may be wound from a wire-like material: The spring element may be disposed parallel and/or concentrically with the longitudinal axis of the injection device.
[0017] In some preferred embodiments, a spring in accordance with the present invention may fulfil a dual function, namely that of pushing the product container into its fixed seating and that of providing the requisite force for the element which moves back to an initial position when a dispensing operation has terminated. An advantage of using a spring to urge or push the product container into its fixed seat or location is that it offers an easy way of compensating for variations in the longitudinal tolerances of product containers. It also allows an injection device to be used with product containers produced by different manufacturers. Another advantage of using a spring with a dual function is that it may replace or avoid the use of two separate springs, one of which pushes the product container and the other of which pushes the operating element, thereby reducing costs.
[0018] In some embodiments, the element which can be moved back to its initial position after the dispensing operation has terminated may prevent, e.g. lock, a movement of the output element relative to the housing when it is in a coupled state and unlock, i.e. release it, relative to the housing when it is in an uncoupled state. In some preferred embodiments, this locking effect is provided by an anti-rotation lock. In some preferred embodiments, to effect a dispensing operation, the moveable element, which may be a part of a coupling, is moved out of the coupled engagement for a dispensing operation. To this end, it may be moved out of the coupled engagement by the operating element, in which case the operating element is operated, e.g. pushed, as a result of which the element is moved out of the coupled engagement against the spring force of the spring element. The element may be able to be moved axially relative to a housing and/or the drive unit of the injection device, but not rotate. The dispensing movement of the output element, which may be a plunger rod and have a freely rotatable but axially fixed flange on its end, can be effected relative to the housing or a locating element which moves into or is positioned in the output element. In some embodiments, the locating element may locate in (or be received in or coupled to) the output element so that the output element can be moved axially relative to the locating element in and/or opposite the dispensing direction, e.g. turned or screwed. For example, the locating element may have an internal thread which locates in and/or complements an external thread of the output element. Alternatively, the output element may be longitudinally guided by the locating element. The locating element may be secured so that it is not able to rotate relative to the housing and may also be secured so that it can not move axially, although this is not necessarily the case. In some preferred embodiments, the locating element is able to move axially relative to the housing, in which case it is secured to the housing so that it can not move axially when a product container has been inserted and secured on the drive unit.
[0019] In some preferred embodiments, the output element which acts on the product to be dispensed to dispense the product, e.g. via the plunger, is coupled with the re-settable element in such a way that its dispensing movement is locked when the product container is not attached. This means that triggering is not possible if a product container has not been inserted.
[0020] In some preferred embodiments, the output element is unlocked and can effect a rotating movement in the state in which a product container has not been inserted so that the output element can be screwed back, e.g. in the proximal direction, by a rotating movement of the output element into the drive unit if a product container has not been inserted or if a product container holder has been removed. In some preferred embodiments, the thread by which the locating element locates in the output element has a pitch which does not cause any frictional resistance of the thread when placed under axial load. When pressure is applied to the output element, e.g. to the flange thereof, in the proximal direction, it is able to move easily in the proximal direction without the user having to apply a rotating movement to the output element. If a product container has been removed or if a product container holder has been removed, the locating element can be moved between a first position and a second position, and in the first position, the output element is uncoupled from the element so that the output element is able to move in or opposite the dispensing direction. Providing the product container or the product container holder has been attached to the drive unit, the locating element is moved into its second position, thereby preventing a rotating movement of the output element. For example, the locating element may be moved by the product container or by the product container holder directly or indirectly, for example by the fixing device. The product container or the product container holder may constitute or incorporate a part of the fixing device. A movement out of an unsecured state into the secured state, e.g. a rotating movement of the product container or product container holder, in some preferred embodiments, a combined rotating-axial movement, causes the locating element to move.
[0021] In some preferred embodiments, the locating element is coupled with the fixing device so that when the product container or product container holder is attached or released, it is moved axially on or by the drive unit. The locating element may be connected in an axially fixed arrangement to a coupling element, such as a coupling sleeve, which is in turn able to rotate relative to the locating element. The coupling element may be sleeve-shaped and surround the output element or at least cooperate with the output element so that the output element is able to move axially relative to the coupling element but not rotate. The coupling element may locate in a longitudinal groove of the output element. The coupling element may be part of a transmission which transmits the torque of the drive element to the output element. Another element may be connected to the drive element in a fixed torque-transmitting arrangement, such as a drive shaft which is or can be coupled with the output element, due to the fact that the drive shaft can be coupled with the output element via a coupling which can be axially engaged with and released from the output element. To this end, the coupling element and the drive shaft may form part of the coupling, which can be coupled and uncoupled.
[0022] In some embodiments, the coupling element may also have projections, which are moved into engagement or out of engagement with the re-settable element depending on the desired operating mode.
[0023] In some preferred embodiments, the spring element fulfilling the dual function is disposed between a re-settable element and the product container. It may be advantageous if the re-settable element is subjected to a force acting in the proximal (rearward) direction by the spring and the product container is subjected to a force acting in the distal (forward) direction by the spring. The spring element may act directly or indirectly on the product container. In some preferred embodiments, the spring acts via one or more parts disposed between the product container and the spring element. For example, a retainer or retaining element may be disposed between the product container and spring element, which pushes on the proximal end of the product container by its distal end. The retaining element may have an axial stop which prevents the spring element from fully relaxing when a product container is being removed or has been removed. For example, the stop may move into an abutting contact with the locating element so that the retaining element is moved axially by a distance which is limited but long enough to compensate for longitudinal tolerances of the product container. The retaining element may be displaceable relative to the locating element and/or to the housing. The arrangement may be such that the spring expends a force on the re-settable element and also on the operating element for example, when a product container is inserted.
[0024] In some embodiments, one or more parts, e.g. at least one other part, may be provided between the spring and operating element, in addition to the re-settable element, which can be moved by the operating element and/or by the element which is re-settable by the spring element. For example, a bearing may be provided between the operating element and the re-settable element, which provides a bearing for the coupling element transversely to the longitudinal direction, and/or a threaded sleeve which can be used to produce a rotating movement for additional parts of the injection device, e.g. a dose display or a dose stop for the final dose, and/or a brake to restrict the driving speed, and/or a drive element which supplies the driving energy needed to dispense the product. These parts may be moved in the distal direction when the operating element is operated, for example, and in the proximal direction during the re-setting movement of the spring element. This being the case, the spring element also fulfils the function of holding together axially adjoining parts or components. In some embodiments, the spring element may also be used to couple and uncouple various couplings, i.e. supply coupling forces.
[0025] In some embodiments, the spring fulfilling the dual function may be a separate part or component, or it may be a part formed by a structure or element adjoining the spring. If a separate spring is provided, it may be made from a suitable material, e.g. plastic, metal, etc. In some embodiments, if the spring is an integral part of another component, the spring may be made from plastic because it can be injection molded with the other part. An advantage of this is that it may be possible to reduce costs. Alternatively, in using a metal spring, the element which the spring is part of can be cast around it. This may be done by a simple injection casting process. For example, the spring may be integral with the re-settable element or integral with a supporting ring which may be provided as a separate part between the spring and retaining element, or integral with the retaining element which pushes on the product container and/or comprises an axial stop. Another option is for the retaining element, spring and re-settable element to be of an integral design.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a cross-sectional view illustrating a proximal (rear) part of an embodiment of an injection device in accordance with the present invention,
[0027] FIG. 2 is a perspective view of an embodiment of a housing part with a guide track for a bayonet lock and an inserted bayonet sleeve,
[0028] FIG. 3 is a perspective view of the bayonet sleeve illustrated in FIG. 2 ,
[0029] FIG. 4 is a perspective view of the bayonet sleeve illustrated in FIG. 3 with a locating element inserted in it,
[0030] FIG. 5 is a perspective view of a bayonet sleeve and product container holder, which is moved axially into a fixed torque-transmitting engagement,
[0031] FIG. 6 is a perspective view of an output element with a flange and spring element,
[0032] FIGS. 7A and 7B are, respectively, an exploded diagram and a perspective view of one embodiment of a brake mechanism in accordance with the present invention,
[0033] FIG. 8 is a perspective, exploded diagram of another embodiment of a brake mechanism in accordance with the present invention,
[0034] FIG. 9 is a diagram schematically plotting braking force as a function of angular speed,
[0035] FIG. 10 is a diagram illustrating braking action as a function of time,
[0036] FIGS. 11A and 11B are, respectively, an exploded view and a perspective view of an embodiment of a brake mechanism in accordance with the present invention operating on the principle of an eddy current brake,
[0037] FIG. 12 is a perspective view of another embodiment of a brake mechanism in accordance with the present invention operating on the principle of a centrifugal brake,
[0038] FIG. 13 is an exploded view of another embodiment of a brake mechanism in accordance with the present invention operating on the principle of a fluidic brake, and
[0039] FIG. 14 is a perspective view of a brake housing from FIG. 13 .
DETAILED DESCRIPTION
[0040] With regard to fastening, mounting, attaching or connecting components of the present invention, unless specifically described as otherwise, conventional mechanical fasteners and methods may be used. Other appropriate fastening or attachment methods include adhesives, welding and soldering, the latter particularly with regard to the electrical system of the invention, if any. In embodiments with electrical features or components, suitable electrical components and circuitry, wires, wireless components, chips, boards, microprocessors, inputs, outputs, displays, control components, etc. may be used. Generally, unless otherwise indicated, the materials for making embodiments of the invention and/or components thereof may be selected from appropriate materials such as metal, metallic alloys, ceramics, plastics, etc. Unless otherwise indicated specifically or by context, positional terms (e.g., up, down, front, rear, distal, proximal, etc.) are descriptive not limiting. Same reference numbers are used to denote same parts or components.
[0041] The injection device illustrated in FIG. 1 comprises a drive unit, which, in some embodiments, can be used more than once, and a product container 27 connected to it, which is accommodated in a sleeve-shaped product container holder 16 which can be used multiple times, for example, and which can be secured to the drive unit with the aid of the product container holder 16 . The product container 27 can be removed from the injection device after it is empty, disposed of and replaced with a new one. With a view to simplifying the manufacturing and assembly processes, the housing 12 is of a multi-part design comprising housing elements 12 a, 12 b connected to or inserted in it, although in principle, the housing could also comprise a single part. The product container 16 is attached to the drive unit by a bayonet fitting, which is formed by the housing 12 , product container holder 16 and sleeve 50 . The product container holder 16 is covered by a cap 31 , which is fitted on the housing 12 , and can be removed in preparation for using the injection device and then fitted back on it.
[0042] FIGS. 2 to 5 illustrate elements of the fixing device provided in the exemplary form of a bayonet fitting. The product container holder 16 has a cam 16 c extending radially outwardly and at its proximal (rear) end face is designed so that it can be connected in a positive fit, i.e. in a fixed torque-transmitting fit, to the distal (forward) end face of the sleeve 50 , as illustrated in FIG. 5 where housing part 12 a has been omitted for illustration purposes. The sleeve 50 has at least one cam 50 c extending radially outwardly, which forms a part of a cam (which may be thought of as comprising cam elements 16 c, 50 c ) for the fixing device. The cam 50 c locates or is positioned in a guide track 12 e formed in the housing 12 , e.g. in housing part 12 a, which has at least one inclined surface 12 g. When the sleeve 50 is moved in rotation, the sleeve 50 moves axially relative to the housing part 12 a as well as moving in rotation, due to the locating cam 50 c. As will be described below, the axial movement of the sleeve 50 results in various advantageous effects.
[0043] To fit the product container 27 on the drive unit, it may be introduced into the product container holder 16 via the proximal end. The product container holder 16 is then snap-fitted onto the sleeve 50 by an axial movement resulting in a fixed torque-transmitting fit ( FIG. 5 ), so that the cams 16 c are inserted through the opening 12 f ( FIG. 2 ) into the guide track 12 e. FIG. 2 illustrates the bayonet fitting in a locked state without the product container holder 16 . In an unlocked state in which the cams 50 c are disposed in the region of, and axially flush with the openings 12 f, the product container holder 16 can be push-fitted. The cams 16 c and 50 c then lie one against the other and form a common cam ( FIG. 5 ). A rotation of the product container holder 16 causes the sleeve 50 to be driven. Due to the inclined faces 12 g, the sleeve 50 and the product container holder 16 are also moved axially. At the end of the rotation, i.e. on reaching the locked position, the common cam (comprising cam elements 16 c, 50 c ) is disposed in the region 12 h of the guide track 12 e in which the two cams 16 c and 50 c are axially clamped together by the sides of the guide track 12 e. To this end, the axial width of the guide track in the region 12 h is approximately as wide as that of the joint cams 16 c, 50 c.
[0044] As illustrated in FIG. 4 , a guide sleeve 26 is accommodated in the sleeve 50 , which may also be thought of and/or referred to as the bayonet sleeve. The guide sleeve 26 is connected to the housing 12 so that it can not rotate but can move axially and is connected to the bayonet sleeve 50 so that it can rotate but can not move axially. As a result, when the bayonet sleeve 50 is moved from the unlocked to the locked position and vice versa, the guide sleeve 26 effects a longitudinally guided movement relative to the housing 12 .
[0045] As may be seen from FIG. 1 , a threaded insert 6 is connected and/or latched to the guide sleeve 26 so that it can not rotate or move axially. The threaded insert 6 and guide sleeve 26 may be thought of and/or referred to as a locating element (comprising insert and sleeve elements 6 , 26 ). The threaded insert 6 has an internal thread 6 a in which the external thread 2 a of an output element 2 , which might also be called a plunger rod in this example, is guided so that when the output element 2 is rotated, it is guided by the internal thread 6 a of the threaded insert 6 in the proximal direction or in the distal, i.e. opposite, direction, as it is screwed, depending on the direction of rotation.
[0046] On its external face, the output element 2 has a thread 2 a, which is interrupted by two grooves 2 b extending in the axial direction lying opposite one another on the circumference. A coupling sleeve 5 constituting part of a transmission (comprising elements 7 , K 2 , 5 ) has two projections 5 a, 5 b directed radially inwardly lying opposite one another on its distal end which project into the grooves 2 b of the output element 2 . The coupling sleeve 5 is connected to the locating element so that it can rotate but is not able to move axially. Accordingly, the output element 2 is locked to prevent it from rotating relative to the coupling sleeve 5 but is able to move axially relative to the coupling sleeve 5 when it is rotated relative to the locating element. The coupling sleeve 5 is not able to move axially expect for when the product container 27 is being replaced.
[0047] A drive shaft 7 provided at the proximal end of the injection device and forming part of the transmission has teeth 7 a extending radially inwardly which constitute a coupling element of the coupling K 2 . When operated, i.e. when an operating element 15 is pushed in the distal (forward or injection) direction, the drive shaft 7 and as a result also the teeth 7 a are moved in the distal direction, as result of which the teeth 7 a locate in the proximal end of the coupling sleeve 5 and establish a fixed torque-transmitting, positive connection.
[0048] A spring element or drive spring 3 , which may be provided in the form of a helical spring or clock spring, is connected to the housing 12 by one end via a spring sleeve 8 on the external face of the spring 3 . The spring sleeve 8 is prevented from rotating relative to the housing 12 but is able to move axially. At the other end, the drive spring 3 is connected to the drive shaft 7 . As a result, energy stored in the spring 3 can be output as a rotating movement of the drive shaft 7 relative to the housing 12 . To dispense a product, the energy of the spring element 3 is transmitted via the transmission element in the form of a rotating movement to the output element so that the latter is screwed relative to the locating element in the distal direction, i.e. in the dispensing direction, and pushes the plunger 28 , causing the product to be dispensed from the product container 27 .
[0049] To set a product dose to be administered, a user can rotate the dose setting element 9 provided in the form of a dose setting button, which is axially fixed relative to the housing 12 . The dose setting element 9 is coupled with a coupling element 10 via the coupling K 3 so that it is prevented from rotating. The coupling K 3 is formed by webs or grooves or teeth of the dose setting button 9 , which co-operate in a positive fit with webs or grooves or teeth of the coupling disc 10 to establish a coupling which can be released by a movement of the coupling element 10 in the distal direction. The coupling element 10 can be moved and thus released by operating the operating element 15 . When in a state of not being operated, the coupling K 3 is held in a coupled state and the coupling K 2 in an uncoupled state by a spring element 19 , which pushes the drive shaft 7 in the proximal (rear or rearward) direction. During the dose setting operation, the coupling K 3 is coupled, i.e. a rotating movement of the dose setting button 9 is transmitted to the coupling element 10 . The coupling element 10 is connected to the drive shaft 7 so that it can not move axially and can not rotate and could also be an integral part of the drive shaft 7 . The rotating movement of the dose setting element 9 is not transmitted to the coupling sleeve 5 because the coupling K 2 is uncoupled.
[0050] When the drive shaft 7 is rotated, the drive spring 3 connected to the drive shaft 7 is tensed. To prevent the dose setting button 9 from being turned back due to the drive spring 3 as it is tensed during the setting operation, a ratchet 11 or a ratchet mechanism, which may comprise a ratchet spring 11 a, e.g. for clamping retaining elements, may be provided between the housing 12 of the injection device, the components of which might, for example, be a mechanical holder 12 a and a mechanical holder 12 b and the dose setting button 9 . The ratchet mechanism may be designed so that a rotation and/or a tensing of the drive spring 3 is possible in only one direction. In some preferred embodiments, however, the ratchet mechanism is designed so that the rotating action is possible in both directions, e.g. tensing and relaxing of the drive spring 3 . Due to the fact of being able to rotate in both directions, a product dose can be both increased and reduced when setting the product dose. A currently set product dose can be read through the window 12 d of a display barrel 4 .
[0051] The rotating movement of the drive shaft 7 is also transmitted to the threaded sleeve 13 , which is connected to the drive shaft 7 so that it is not able to move axially or rotate and may also be an integral part of it. The threaded sleeve 13 has at least one groove on its external circumference 13 a in which at least one web 4 a of the display barrel 4 locates so that a rotating movement of the threaded sleeve 13 is transmitted to the display barrel 4 by the anti-rotation coupling, permitting an axial relative movement between the display barrel 4 and threaded sleeve 13 . The display barrel 4 has a thread 4 b on its external face which locates in an internal thread 12 c of the housing part 12 b so that the display barrel 4 is moved due to a rotating movement in the axial direction relative to the housing 12 , e.g. in the distal direction. In some preferred embodiments, the display barrel 4 moves in the distal direction of the injection device (towards the left in FIG. 1 ) during the process of setting and priming the dose by rotating the dose setting button 9 . A marking may be provided on the external face of the display barrel 4 , such as print, a dose display or a scale, which can be read through an opening or a window 12 d in the housing 12 b of the injection device, and the marking of the display barrel 4 is moved relative to the window 12 d. The display barrel 4 has a rotation stop on its distal end acting in the circumferential direction which moves into an abutting contact with a co-operating complementary stop disposed on the housing part 12 a on reaching the maximum dose. The complementary stop is formed by a terminal end of an annular gap of the housing part 12 a. An advantage of using a stop which acts in the circumferential direction rather than an axial stop is that the forces acting on the stop are weaker. The display barrel 4 also has another rotation stop on its proximal end acting in the circumferential direction, which moves into an abutting contact with a co-operating complementary stop on the housing 12 b on reaching a minimum dose. The complementary stop is formed by the proximal end of the thread 12 c.
[0052] Once the dose has been set and the drive spring 3 primed by rotating the dose setting button 9 , the setting operation is complete. In some preferred embodiments, the dose is primed as the spring 3 is tensed. To correct or adjust the dose, the dose setting button 9 simply has to be rotated in the opposite direction, e.g. to reduce a dose which might have been set too high. In some embodiments, the ratchet 11 may be designed as illustrated in FIGS. 14 and 15 of patent application PCT/CH2007/000243 and/or US Publication 2009/0254035, the teachings of which are incorporated herein by reference.
[0053] During the dispensing process, which is triggered by depressing the push button 15 , the display barrel 4 is rotated back in the opposite direction and is moved back in the proximal direction due to the thread engagement with the internal thread 12 c of the injection device (to the right in FIG. 1 ). As this happens, it reaches a stop of the display barrel 4 acting in the circumferential direction on the housing of the injection device, e.g. on the housing part 12 b. In an unbraked dispensing movement in which the threaded rod 2 is moved in the distal direction without any opposing force, e.g. when no product container has been inserted, this operation may result in too high a strain and, in an extreme situation, deformation or even damage to the display barrel 4 or co-operating part 12 b. A brake mechanism (e.g. comprising brake elements, e.g. shoe halves and disc 17 , 18 ) acting on the driving movement is therefore provided, which will be described below.
[0054] The coupling K 1 , comprising the coupling element acting as a lock sleeve 14 and the coupling sleeve 5 , is used to couple the coupling sleeve 5 with the housing 12 so that it can not rotate in specific operating modes or to release it to permit a rotation relative to the housing 12 . The coupling K 1 is uncoupled when the product container 27 is being replaced to enable the output element 2 to be pushed back or screwed in the proximal direction again and to enable the output element 2 to be screwed in the distal direction while product is being dispensed. The coupling K 1 is coupled when the product container is attached to the drive unit and the operating element 15 is not being operated. The coupling K 1 is provided in the form of teeth on the external face of the coupling sleeve 5 , which mesh in teeth on the internal face of the lock sleeve 14 . As a result, the coupling sleeve 5 is prevented from rotating relative to the lock sleeve 14 . The lock sleeve 14 is mounted in the injection device so that it can not rotate but can move axially relative to the housing 12 and the coupling sleeve 5 .
[0055] During a dispensing operation, the threaded sleeve 13 is moved in the distal (forward or injection or delivery) direction by operating the operating element 15 . As this happens, the threaded sleeve 13 pushes on the bearing 29 , which is provided in the form of a ball bearing in this example but may also be a simple slide bearing, so that the bearing 29 pushes against the lock sleeve 14 , thereby moving it in the distal direction for a dispensing operation, and holds it in a distal position during a dispensing operation. The coupling element 14 is therefore disposed distally of the projections of the coupling sleeve 5 for the coupling K 1 . As a result, the coupling K 1 remains uncoupled for the duration of the dispensing operation.
[0056] When the operating element 15 is operated, the couplings K 1 , K 2 and K 3 operate as follows. By depressing the push button 15 seated on the coupling element 10 and/or drive shaft 7 , the coupling element 10 is pushed in the distal direction together with the push button 15 and the drive shaft 7 . As a result, the coupling K 2 is coupled so that the drive shaft 7 is prevented from rotating relative to the coupling sleeve 5 . The coupling K 1 is then uncoupled due to the movement of the lock sleeve 14 , against which the threaded sleeve 13 connected to the drive shaft 7 pushes via the axially displaceable bearing 29 . Alternatively, the couplings K 1 and K 2 may be connected in the reverse sequence.
[0057] Once K 2 is coupled and K 1 is uncoupled, the coupling K 3 is also uncoupled due to the movement of the coupling element 10 relative to the dose setting button 9 . The coupling element 10 , which is connected to the drive shaft 7 , is able to rotate relative to the housing 12 once the coupling K 3 is uncoupled. The energy or force stored in the drive spring 3 during priming can be transmitted to the drive shaft 7 . Accordingly, a torque is applied to the drive shaft 7 , which is transmitted by the coupled coupling K 2 to the coupling sleeve 5 , which rotates in unison with the drive shaft 7 and transmits this rotating movement to the output element 2 , which is coupled with the coupling sleeve 5 so that it can not rotate. The output element 2 , provided in the form of a threaded rod in this example, converts the rotating movement into an axial movement in the distal direction due to the thread engagement 2 a, 6 a with the locating element (comprising elements 6 , 26 ), so that the flange 1 provided on the distal end of the threaded rod 2 , which may also be construed as part of the output element, is moved in the distal direction of the injection device.
[0058] Since, during the product dispensing operation, the threaded sleeve 13 moves in the direction opposite that in which it moves during priming, the display barrel 4 likewise moves in the direction opposite that of the priming operation.
[0059] In the normal situation, i.e. when a pre-set product dose has been fully dispensed, the dispensing operation and the movement of the output element 2 in the distal direction continues until the display barrel 4 makes contact with the above-mentioned stop acting in the circumferential direction. In some embodiments, this happens when the value which can be read through the window 12 d has been rotated back to 0 .
[0060] In the situation in which the user of the device releases the operating element 15 as the product is being dispensed, the couplings couple in the order which is the reverse of that in which they uncoupled or coupled during operation. The product dispensing operation is interrupted, as a result of which the value may be seen through the window 12 d represents the amount still to be dispensed had the pre-set dose been fully dispensed. The product dispensing operation can be continued by depressing the operating element 15 again, and dispensing can be stopped again by releasing the operating element 15 or the user can wait until the product has been fully dispensed.
[0061] In the situation in which the product container contains less product than the maximum dose indicated on the display barrel, the injection device based on this example has an additional device for limiting the maximum dose which can be set for the last time, to prevent the possibility of a bigger product dose being set than that which is still in the container. To this end, a traveller 30 is provided, which at least partially surrounds the coupling sleeve 5 and locates with the coupling sleeve 5 in such a way that the traveller 30 is not able to rotate relative to the coupling sleeve 5 but is able to move axially. The traveller 30 also locates or is positioned by a thread on its external circumference that engages with an internal thread of the threaded sleeve 13 . This arrangement causes an axial movement of the traveller 30 when there is a relative rotation between the threaded sleeve 13 and coupling sleeve 5 , and when there is no relative rotation the traveller 30 does not effect an axial movement. When setting a product dose, the threaded sleeve 13 turns relative to the coupling sleeve 5 so that the traveller 30 moves in the proximal direction. During dispensing, on the other hand, no relative movement takes place between the coupling sleeve 5 and threaded sleeve 13 due to the coupled engagement of the coupling K 2 . Accordingly, the traveller does not move. After setting doses and dispensing product several times, the traveller 30 moves into an abutting contact with the drive shaft 7 , so that it is no longer possible to increase the dose, even if the display would actually permit this.
[0062] The user can replace the product container 27 with a new one. To this end, the product container holder 16 may be removed by rotating the drive unit relative to the housing 12 . As the product container 27 is moved from the secured position into the non-secured position, e.g. as the bayonet fitting is released, the locating element is moved together with the output element 2 and the coupling sleeve 5 in the distal direction relative to the housing 12 and to the coupling element 14 , thereby releasing the coupling K 1 . The projections of the coupling sleeve 5 pointing radially outwardly to establish the coupling K 1 are now disposed distally of the coupling element 14 . The output element 2 can now be screwed into the drive unit with a relatively slight force acting in the proximal direction because the thread of the output element is not retained by friction. As the output element 2 is screwed back, the coupling sleeve 5 is turned relative to the threaded sleeve 13 and so in the direction opposite that during product dispensing, causing the traveller 30 to be pushed back in the distal direction again. The screwing-back operation may take place against the force of a spring element, at least across a part of the total distance, which tries to push the output element in the distal direction, for example. The spring element may act or be disposed between the output element 2 and the drive shaft 7 for example. Other possible spring elements will be described below specifically with reference to FIG. 6 . It is generally preferred if the force of such a spring element is weaker than the force needed to produce an interaction via the plunger from the output element 2 onto the product.
[0063] Also during the process of removing the product container 27 , the retaining element 25 used to secure the product container 27 in the product container holder 16 is pushed in the distal direction by the spring 19 until it makes contact with the locating element 6 , 26 . This contact prevents the spring 19 from fully relaxing when the product container 27 is removed. This is of advantage because the spring 19 should be able to apply sufficient force to hold the coupling K 3 in a coupled engagement even when a product container 27 has been removed.
[0064] By virtue of another aspect, a spring-mounted flange may be used, as illustrated in FIG. 6 for example.
[0065] After replacing the product container 27 , e.g. an ampoule, capped vial or the like, the user is prompted to proceed with priming, as may be described in operating instructions. This is useful on the one hand because there may be air in the product container 27 and on the other hand because the output element 2 may have been previously pushed fully into the drive unit and a certain amount of clearance may have been created between the plunger 28 and the flange 1 due to the different level to which the product container 27 is filled.
[0066] FIG. 6 illustrates an output element 2 with a flange 1 attached to its front or distal end, which is non-displaceably connected to the threaded rod. Disposed between the flange 1 and the threaded insert 6 illustrated in FIG. 6 is a spring element 38 , which may be provided in the form of resilient arms 38 a extending out at an angle, for example. These resilient arms 38 a may be secured to the flange 1 or/and to the threaded insert 6 . Another option would be to injection mold a suitable elastomer onto the flange 1 or/and onto the threaded insert 6 . After a new product container 27 has been inserted, a clearance may occur between the flange 1 and the plunger 28 , which may be attributable to a difference in the level to which product containers 27 have been filled when full, given that they have a certain tolerance.
[0067] After pushing in the flange 1 connected to the threaded rod 2 , the flange 1 based on the embodiment illustrated in FIG. 1 lies directly against the threaded insert 6 .
[0068] In the embodiment illustrated in FIG. 6 , the at least one spring element 38 has pushed the flange 1 away from the threaded insert 6 in the distal direction by a predefined distance. This means that when a product container 27 has been inserted or while a product container 27 is being inserted, the flange 1 will move into contact with the proximal end of the plunger 28 , even if the plunger 28 is pushed into the product container 27 by differing distances caused by manufacturing tolerances of different product containers. Conventional means for eliminating the clearance between the flange 1 and plunger 28 are therefore no longer absolutely necessary and may even be dispensed with, for example.
[0069] As may be seen from FIG. 1 , the injection device, e.g. the drive unit, comprises a brake (which may be thought of as comprising brake elements or components 17 , 18 ) which decelerates a rotating part, in this example the transmission element or/and the driving movement. If conventional injection devices are used incorrectly, i.e. if no product container has been inserted, but the device is nevertheless operated, there is a risk of placing too high a strain on or even damaging the components of the injection device. When a product container 27 is inserted, the forces and movements which occur are damped by the viscosity of the product during the product dispensing operation. In the absence of a product container, there is no such damping effect. It is the brake in accordance with the present invention which is used for this purpose, thereby preventing excessive strain.
[0070] FIGS. 7A, 7B and 8 are diagrams on a larger scale illustrating embodiments of a brake mechanism suitable for the device illustrated in FIG. 1 , e.g. a first and second embodiment, respectively, each of which operates in a similar manner. The first embodiment illustrated in FIGS. 7A, 7B has two brake shoe halves 17 latched to one another so that they can not rotate and so that they can also not move axially, which have profiled portions directed toward one another, between which an annular gap is formed in which a brake disc 18 is accommodated. The annular gap is of a defined width and, in an alternative arrangement, the brake shoe halves could move axially relative to one another. The brake shoe 17 could be of an integral design. The brake disc 18 is accommodated so that it can not rotate relative to the housing 12 but can move axially, due to the profiled external circumferential surface of the brake disc locating in a profiled inner circumferential surface of the housing part 12 b. At least one brake shoe half 17 or the entire brake shoe is mounted at least so that it can not rotate in the drive train or transmission element. The sleeve-shaped brake shoe 17 has projections pointing radially inwardly, which locate in a matching profile of the drive sleeve 7 . The brake disc 18 is able to move between the brake shoe halves 17 . The brake disc 18 is mounted so that it can not rotate, e.g. is guided in a groove, and so that it is able to move axially in the injection device or housing part 12 b. The brake disc 18 is toothed on the top and bottom face with teeth 18 a, 18 b on the end face projecting circumferentially in both directions and having an identical or different tooth height ZH, and is mounted or displaceably clamped between the threaded sleeve 13 and the brake shoe 17 , e.g. with a small clearance of approximately a tooth size or tooth height ZH or bigger, the latter having co-operating complementary teeth 13 b respectively 17 a, e.g. with a corresponding or identical tooth height ZH.
[0071] Due to the fixed torque-transmitting connection between the transmission element (which, again, may be thought of and/or referred to as comprising elements 7 , K 2 , 5 ) during a dispensing operation or when what may be thought of and/or referred to as “firing blank,” i.e. when no product container has been inserted, the brake shoe 17 is moved in rotation relative to the brake disc 18 . When this happens, the disposition of the brake shoe teeth 17 a, 17 b ensure that the brake disc 18 oscillates axially between the threaded sleeve 13 and the brake shoe 17 . As a result, the distal teeth 18 a and proximal teeth 18 b of the brake disc 18 move alternately into contact with the co-operating complementary teeth 17 b and 17 a. Due to one or more of the resultant friction, elastic deformation and the oscillating mass, a corresponding loss occurs, thereby limiting the maximum angular speed o of the rotating parts 13 and 17 .
[0072] The embodiment illustrated in FIG. 8 operates on a similar principle, the difference being that one of the two brake shoe halves and/or its end-face tooth profile is formed by the transmission element or the threaded sleeve 13 connected to the transmission element so that it cannot rotate. A fixed, defined distance may be provided between the profiles 17 a and 13 b, or alternatively a variable distance, because the brake shoe half 17 is able to move axially relative to the threaded sleeve 13 . Due to the spring 19 , the profiles 13 b and 17 a can be pushed toward one another so that they move into a meshing contact with the profiles 18 a and 18 b.
[0073] Due to the vibration or oscillation of the brake disc 18 between the threaded sleeve 13 and brake shoe 18 which increases with the angular velocity co, the braking force increases disproportionately as the angular velocity co increases, so that the curve BS of braking forces schematically illustrated in FIG. 9 can be achieved.
[0074] FIG. 9 is a schematic illustration plotting the curve of the braking force which can be achieved by a brake mechanism in accordance with the present invention, from which it may be seen that the braking force rises to an increasing degree with the angular or rotational velocity co. In some preferred embodiments, the braking force is relatively low or zero up to the maximum permissible angular velocity ω max and rises sharply with effect from the maximum permissible angular velocity ω max .
[0075] FIG. 10 illustrates the angle of rotation of the display barrel 4 as a function of time, which is able to effect three full revolutions (3×360°) in the embodiments illustrated as an example. As may be seen from FIG. 10 , the display barrel 4 has completed three full revolutions after the time t non-braked , which is shorter than the time t invention in the case of a decelerated rotating movement of the display barrel 4 during which the angle of rotation increases linearly as a function of time.
[0076] Due to the braking force generated by the oscillating brake disc 18 , the maximum possible angular velocity ω max of a dispensing movement can be reduced or limited so that the backward-rotating display barrel 4 is able to move into an abutting contact with the stop acting in the circumferential direction or the housing part 12 b at only a maximum speed predefined by the brake. If the brake is designed accordingly, the maximum possible contact speed of the display barrel 4 is so low that there is little chance of deformation or damage occurring due to the impact. Other brake mechanisms may also be used as an alternative to a brake disc 18 oscillating between the threaded sleeve 13 and brake shoe 17 .
[0077] For example, as an alternative or in addition, the brake may be based on another embodiment in the form of a centrifugal brake as illustrated in FIG. 12 . In this case outwardly displaceable brake shoes 41 are mounted on the transmission element or/and the drive shaft 7 and/or another part which rotates with the drive shaft 7 , for example the coupling element 10 , the threaded sleeve 13 or the display barrel 4 , which have a mass and which effect the same rotation as the rotating part. The brake shoes 41 may, but need not necessarily, be inwardly or outwardly biased by a spring. The brake shoes may be pivoted or moved radially outwardly by the centrifugal force to move into a braking engagement with a sleeve 42 , for example the housing 12 . In this embodiment, pins 40 or fasteners extending radially outwardly are provided, the ends of which are provided with brake pads 41 biased by the spring, for example. When the rotation speed of the non-braked or only partially braked rotating element is sufficiently high, the brake pads 41 are moved radially outwardly by the centrifugal force, optionally also assisted by the spring-biased support, and can move into contact with an outer static sleeve 42 , thereby producing the desired braking effect due to friction. The outer static sleeve may also be formed by the housing 12 or housing part 12 b.
[0078] In another embodiment illustrated in FIGS. 11A and 11B , the brake may be provided in the form of an eddy current brake 20 , in which case a brake disc 21 may be connected to a rotating part which has to be decelerated, for example the transmission element, drive shaft 7 , threaded sleeve 13 or display barrel 4 , and the elements interacting with the brake disc may be connected to the housing or an element fixedly disposed on the housing or to an element rotating relative to the brake disc.
[0079] In some preferred embodiments, the brake disc 21 is made from a good electrical conductor, such as pure aluminium or copper, for example. Rare earth alloys may be used as the material for the axially magnetised magnets 22 , neodymium for example. The permanent magnetic field may be linked by a magnet yoke 23 made from iron to the air gap, where it extends through the brake disc 21 as vertically as possible. The braking force is created by the surface and flow density in the air gap and the rated current in the brake disc 21 , for which purpose the surface should be as large as possible, the air gap should be as small as possible and the disc thickness should be as big as possible. The braking torque occurs over the averaged radius (working radius). Brakes may be designed with several magnet systems which act on a disc 21 .
[0080] The usual approximation calculations are used to calculate the current density, braking power and hence braking torque of an eddy current brake. Leaving aside the effect of the air gap, it is assumed that there will be a standard cylindrical magnetic flow and it is stipulated as a condition that the pole diameter should be sufficiently small compared with the radius of the disc 21 . At high speeds, the approximation is inaccurate, among other reasons because the magnetic fields caused by the eddy currents cause a not inconsiderable feedback and hence non-linearity.
[0081] In some preferred embodiments, the magnets 22 and the magnet yoke 23 are connected to the housing 12 of the injection device or the housing part 12 b or another non-rotating part to be able to generate the desired eddy current braking effect of the brake disc 21 .
[0082] In another embodiment illustrated in FIGS. 13 and 14 , the brake may be provided in the form of a fluidic or hydrodynamic brake. If a standard fluid is used as the braking medium, the linear braking curve FB indicated in FIG. 4 can be obtained for the eddy current brake. However, if the intention is to achieve a braking force which rises more sharply as a function of angular velocity w, so-called non-Newtonian fluids may be used, as a result of which, unlike a Newtonian fluid, the viscosity does not remain constant but increases when a shearing force acting on the fluid is increased, which is the case as the speed increases. These are what are known as anomalous viscous fluids.
[0083] In the case of the fluidic brake, the braking force is generated by two fluid surfaces moving against one another. In particular, the braking force is generated by a fluid volume which is sheared by a relative movement. The shearing stresses which occur during such movements correspond to the braking force. The volume is provided in the form of a chamber split into two parts 45 a, 46 a, in which the fluid is disposed. One chamber part 46 a is disposed in a rotating part 46 and the other chamber 45 a is disposed in a part 45 relative to which the rotating part 46 is able to rotate. The part 46 may be connected so as to rotate in unison with the drive shaft 7 or to the transmission element or another part which rotates when product is being dispensed. The part 45 rotates in unison with at least the housing 12 or a stationary part on the housing. Furthermore, the part 45 may be able to move axially or may be axially immobile relative to the housing 12 . The sleeve-shaped part 45 may be thought of and/or referred to as a brake housing and the part 46 mounted in the sleeve 45 as a brake shaft. When the brake is in the assembled state, the fluid chamber halves 46 a distributed axially around the external circumference of the brake shaft are axially on a level with the fluid chamber halves 45 a distributed around the internal circumference of the brake housing. More, the same number or fewer fluid chamber halves 45 a may be provided than 46 a. In the assembled state, a slim gap is disposed between the internal diameter of the brake housing 45 and the external diameter of the brake shaft 46 in the region of each of the fluid chamber halves 45 a, 46 a, which may be dimensioned so that fluid is conveyed into the gap or no fluid or virually no fluid is conveyed into the gap when the brake shaft 46 is rotating relative to the brake housing 45 . The brake housing 45 may be axially sealed at both ends with sliding seal elements 47 so that no fluid is able to escape from the brake. The seal elements 47 may be provided in the form of a lid. The lid may be provided as a separate part or serve as the coupling shaft, for example.
[0084] Embodiments of the present invention, including preferred embodiments, have been presented for the purpose of illustration and description. They are not intended to be exhaustive or to limit the invention to, the precise forms and steps disclosed. The embodiments were chosen and described to illustrate the principles of the invention and the practical application thereof, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth they are fairly, legally, and equitably entitled. | An injection device for dispensing a product, the injection device including a moveable element which is moved for a dispensing operation, a spring, a product container holder and a product container, wherein the spring pushes against the moveable element to move the moveable element to an initial position after the dispensing operation has ended and against the product container to seat the product container in the product container holder. | Summarize the information, clearly outlining the challenges and proposed solutions. | [
"CROSS-REFERENCED RELATED APPLICATIONS [0001] This application is a continuation of U.S. Ser.",
"No. 14/612,450 filed Feb. 3, 2015, which is a continuation of U.S. Ser.",
"No. 12/869,362 filed Aug. 26, 2010, issued as U.S. Pat. No. 8,992,487 on Mar. 31, 2015, which is a continuation of International Patent Application No. PCT/CH2009/000078 filed Feb. 26, 2009, which claims priority to German Patent Application No. 10 2008 011 885.0 filed Feb. 29, 2008, the entire contents of each of which are incorporated herein by reference.",
"BACKGROUND [0002] The present invention related to devices for injecting, infusing, administering, dispensing or delivering a substance, and to methods of making and using such devices.",
"More particularly, the present invention relates to an injection device for administering a substance or product such as a medicament or therapeutic substance, e.g. insulin, growth hormone, etc.",
"[0003] The idea of coupling an ampoule (which also may be referred to and/or thought of as a container, carpoule, vial or the like) containing a product to or in an injection device is known from the prior art.",
"Securing an ampoule in a stationary seating, for example in an ampoule holder, when attached to the injection device is also known.",
"In some cases, the ampoule may be screwed into the holder, and the securing or holding may be achieved by a clamping action wherein the product container accommodated in the ampoule holder is clamped between the distal (forward) end of the ampoule holder and a stop which acts on the distal end of the ampoule.",
"SUMMARY [0004] An object of the present invention is to provide an injection device to which a product container can be secured in a reliable, efficient and economic manner.",
"[0005] In one embodiment, the present invention comprises an injection device for dispensing a product, the injection device including a moveable element which is moved for a dispensing operation, a spring, a product container holder and a product container, wherein the spring pushes against the moveable element to move the moveable element to an initial position after the dispensing operation has ended and against the product container to seat the product container in the product container holder.",
"[0006] In one embodiment of an injection device according to the present invention, the device comprises coupling element, a product container, and a spring between the coupling element and the product container, the spring biasing or urging the coupling element in one direction and the product container in the other, i.e. opposite, direction.",
"[0007] In some embodiments, the present invention comprises an injection device whereby an injection may be administered manually by the user or may take place automatically.",
"For example, a user of an embodiment of the device designed for automatically dispensing the product may operate an operating element which releases a drive element, for example a spring, and the spring force acts indirectly or directly on an output element and/or pushes the plunger of a product container in a dispensing direction.",
"The drive element may be a motor, a pyrotechnic propellant charge or, as in some preferred embodiments of the present invention, a spring, e.g. a mechanical spring.",
"If the drive element is of the type which stores energy, in some preferred embodiments the stored energy can be released by an operating element so that a driving movement can be converted into an output movement.",
"In some embodiments, the driving movement may be a rotating movement, and the output movement may be a linear movement.",
"[0008] In some preferred embodiments, the drive element may be a rotating spring, e.g. a helical or clock spring, which is wound about the longitudinal axis of the injection device.",
"For example, the spring may be supported in a fixed arrangement on the housing in at least one direction of rotation by one end and connected to the output element or a part which is or can be coupled with the output element by the other end.",
"Thus, the rotational energy stored in the spring may be converted into a driving movement.",
"In some embodiments, it is advantageous to use a strip-shaped helical spring.",
"[0009] In some embodiments, an injection device in accordance with the present invention may be disposable.",
"Generally, in such embodiments, a product container inserted or built into the device during production can not be replaced, and when empty or after the injection device has been used, it is disposed of as a whole together with the product container.",
"[0010] In some embodiments, an injection device in accordance with the present invention is designed to be used more than once.",
"This is practical if the injection device is fitted with high-quality and/or high-tolerance components designed to make it easy to dispense a product and which may be too expensive for use with disposable items.",
"In some embodiments, a driving mechanism is incorporated in a drive unit, in which case the product container can be attached to the drive unit, and can be detached from the drive unit.",
"An empty product container can be released from the drive unit, disposed of and replaced by a new one.",
"[0011] In some preferred embodiments, the product container is received and/or seated in a product container holder.",
"The product container holder is sleeve-shaped and has an opening through which the product container can be inserted into the interior of the sleeve.",
"The opening may be disposed laterally or on an end, e.g. the proximal (rear) end, of the product container holder.",
"At the side, the product container holder may have a region through which it is possible to see from the outside into the interior of the container to, for example, ascertain whether a product container has been inserted or to check how full an inserted product container is.",
"The product container holder may have a collar at its distal (forward) end, against which the product container sits in an abutting contact in its inserted state.",
"The product container is then fixedly seated in the product container holder.",
"The product container holder may have a conical shape, and the product container can be pushed into it to obtain a fixed seating.",
"[0012] In some preferred embodiments, an injection device in accordance with the present invention, e.g. the drive unit thereof, may comprise a spring element, such as a mechanical spring, a gas compression spring or other elastic means, which acts on or pushes on the product container, e.g. the part of the product container relative to which the plunger can be displaced.",
"In some preferred embodiments, the spring element may push the product container into a fixed seating with and/or within the product container holder.",
"In some preferred embodiments, the spring element may act in the longitudinal direction of the injection device.",
"[0013] In some embodiments of the present invention, the product container may be an ampoule or capped vial, for example, and is open at its proximal (rear) end and closed at its distal (forward or front) end.",
"An output element of the drive unit may extend through the proximal end into the product container to act on a plunger or piston in the container, which plunger or piston can be displaced relative to the product container wall.",
"The distal end may incorporate or carry a needle, or may be designed so that a needle can be attached, thereby establishing a flow connection to the interior of the product container due to the fact that the needle pierces a septum disposed on the distal end of the product container.",
"In some preferred embodiments, the wall of the product container is cylindrical, and it may be tightly enclosed by the sleeve-shaped product container holder or enclosed with a slight clearance.",
"[0014] In some embodiments, the injection device may have an element which is moved back into an initial position after a dispensing operation has ended or as it is ending.",
"This may be an operating element which can be operated by moving it, e.g. by moving it axially along a longitudinal axis of the injection device.",
"The element may be moved into a dispensing position as the dispensing operation is being actuated or triggered, in which case the direction of movement needed for this purpose is opposite the direction of movement in which the element can move on terminating the dispensing operation.",
"The operating element may be operated by a user of the device to trigger and/or stop dispensing of the product, or it may be released after the product has been dispensed whereby it moves back or automatically returns to its initial position.",
"A lock element may be coupled with the operating element so that it is axially locked, at least in one direction and, in some preferred embodiments, in both directions.",
"[0015] In some embodiments, the operating element moves back or can be moved back to an initial position after the dispensing operation has terminated.",
"Thus, an injection device in accordance with the present invention may comprise a coupling, e.g. a coupling element which establishes or releases a coupling as it is moved.",
"For example, such a coupling element may be coupled with the operating element in at least one direction and at least for a certain time.",
"The coupling element may push the operating element in one direction, and in the other, opposite direction, the operating element may push the coupling element.",
"[0016] In some preferred embodiments, the element which is moveable when a dispensing operation is terminated or triggered may be moved back into an initial position by a spring element when the dispensing operation has terminated.",
"The spring element may also urge the product container into its fixed seating.",
"In some preferred embodiments, the spring element is a helical spring, which may be wound from a wire-like material: The spring element may be disposed parallel and/or concentrically with the longitudinal axis of the injection device.",
"[0017] In some preferred embodiments, a spring in accordance with the present invention may fulfil a dual function, namely that of pushing the product container into its fixed seating and that of providing the requisite force for the element which moves back to an initial position when a dispensing operation has terminated.",
"An advantage of using a spring to urge or push the product container into its fixed seat or location is that it offers an easy way of compensating for variations in the longitudinal tolerances of product containers.",
"It also allows an injection device to be used with product containers produced by different manufacturers.",
"Another advantage of using a spring with a dual function is that it may replace or avoid the use of two separate springs, one of which pushes the product container and the other of which pushes the operating element, thereby reducing costs.",
"[0018] In some embodiments, the element which can be moved back to its initial position after the dispensing operation has terminated may prevent, e.g. lock, a movement of the output element relative to the housing when it is in a coupled state and unlock, i.e. release it, relative to the housing when it is in an uncoupled state.",
"In some preferred embodiments, this locking effect is provided by an anti-rotation lock.",
"In some preferred embodiments, to effect a dispensing operation, the moveable element, which may be a part of a coupling, is moved out of the coupled engagement for a dispensing operation.",
"To this end, it may be moved out of the coupled engagement by the operating element, in which case the operating element is operated, e.g. pushed, as a result of which the element is moved out of the coupled engagement against the spring force of the spring element.",
"The element may be able to be moved axially relative to a housing and/or the drive unit of the injection device, but not rotate.",
"The dispensing movement of the output element, which may be a plunger rod and have a freely rotatable but axially fixed flange on its end, can be effected relative to the housing or a locating element which moves into or is positioned in the output element.",
"In some embodiments, the locating element may locate in (or be received in or coupled to) the output element so that the output element can be moved axially relative to the locating element in and/or opposite the dispensing direction, e.g. turned or screwed.",
"For example, the locating element may have an internal thread which locates in and/or complements an external thread of the output element.",
"Alternatively, the output element may be longitudinally guided by the locating element.",
"The locating element may be secured so that it is not able to rotate relative to the housing and may also be secured so that it can not move axially, although this is not necessarily the case.",
"In some preferred embodiments, the locating element is able to move axially relative to the housing, in which case it is secured to the housing so that it can not move axially when a product container has been inserted and secured on the drive unit.",
"[0019] In some preferred embodiments, the output element which acts on the product to be dispensed to dispense the product, e.g. via the plunger, is coupled with the re-settable element in such a way that its dispensing movement is locked when the product container is not attached.",
"This means that triggering is not possible if a product container has not been inserted.",
"[0020] In some preferred embodiments, the output element is unlocked and can effect a rotating movement in the state in which a product container has not been inserted so that the output element can be screwed back, e.g. in the proximal direction, by a rotating movement of the output element into the drive unit if a product container has not been inserted or if a product container holder has been removed.",
"In some preferred embodiments, the thread by which the locating element locates in the output element has a pitch which does not cause any frictional resistance of the thread when placed under axial load.",
"When pressure is applied to the output element, e.g. to the flange thereof, in the proximal direction, it is able to move easily in the proximal direction without the user having to apply a rotating movement to the output element.",
"If a product container has been removed or if a product container holder has been removed, the locating element can be moved between a first position and a second position, and in the first position, the output element is uncoupled from the element so that the output element is able to move in or opposite the dispensing direction.",
"Providing the product container or the product container holder has been attached to the drive unit, the locating element is moved into its second position, thereby preventing a rotating movement of the output element.",
"For example, the locating element may be moved by the product container or by the product container holder directly or indirectly, for example by the fixing device.",
"The product container or the product container holder may constitute or incorporate a part of the fixing device.",
"A movement out of an unsecured state into the secured state, e.g. a rotating movement of the product container or product container holder, in some preferred embodiments, a combined rotating-axial movement, causes the locating element to move.",
"[0021] In some preferred embodiments, the locating element is coupled with the fixing device so that when the product container or product container holder is attached or released, it is moved axially on or by the drive unit.",
"The locating element may be connected in an axially fixed arrangement to a coupling element, such as a coupling sleeve, which is in turn able to rotate relative to the locating element.",
"The coupling element may be sleeve-shaped and surround the output element or at least cooperate with the output element so that the output element is able to move axially relative to the coupling element but not rotate.",
"The coupling element may locate in a longitudinal groove of the output element.",
"The coupling element may be part of a transmission which transmits the torque of the drive element to the output element.",
"Another element may be connected to the drive element in a fixed torque-transmitting arrangement, such as a drive shaft which is or can be coupled with the output element, due to the fact that the drive shaft can be coupled with the output element via a coupling which can be axially engaged with and released from the output element.",
"To this end, the coupling element and the drive shaft may form part of the coupling, which can be coupled and uncoupled.",
"[0022] In some embodiments, the coupling element may also have projections, which are moved into engagement or out of engagement with the re-settable element depending on the desired operating mode.",
"[0023] In some preferred embodiments, the spring element fulfilling the dual function is disposed between a re-settable element and the product container.",
"It may be advantageous if the re-settable element is subjected to a force acting in the proximal (rearward) direction by the spring and the product container is subjected to a force acting in the distal (forward) direction by the spring.",
"The spring element may act directly or indirectly on the product container.",
"In some preferred embodiments, the spring acts via one or more parts disposed between the product container and the spring element.",
"For example, a retainer or retaining element may be disposed between the product container and spring element, which pushes on the proximal end of the product container by its distal end.",
"The retaining element may have an axial stop which prevents the spring element from fully relaxing when a product container is being removed or has been removed.",
"For example, the stop may move into an abutting contact with the locating element so that the retaining element is moved axially by a distance which is limited but long enough to compensate for longitudinal tolerances of the product container.",
"The retaining element may be displaceable relative to the locating element and/or to the housing.",
"The arrangement may be such that the spring expends a force on the re-settable element and also on the operating element for example, when a product container is inserted.",
"[0024] In some embodiments, one or more parts, e.g. at least one other part, may be provided between the spring and operating element, in addition to the re-settable element, which can be moved by the operating element and/or by the element which is re-settable by the spring element.",
"For example, a bearing may be provided between the operating element and the re-settable element, which provides a bearing for the coupling element transversely to the longitudinal direction, and/or a threaded sleeve which can be used to produce a rotating movement for additional parts of the injection device, e.g. a dose display or a dose stop for the final dose, and/or a brake to restrict the driving speed, and/or a drive element which supplies the driving energy needed to dispense the product.",
"These parts may be moved in the distal direction when the operating element is operated, for example, and in the proximal direction during the re-setting movement of the spring element.",
"This being the case, the spring element also fulfils the function of holding together axially adjoining parts or components.",
"In some embodiments, the spring element may also be used to couple and uncouple various couplings, i.e. supply coupling forces.",
"[0025] In some embodiments, the spring fulfilling the dual function may be a separate part or component, or it may be a part formed by a structure or element adjoining the spring.",
"If a separate spring is provided, it may be made from a suitable material, e.g. plastic, metal, etc.",
"In some embodiments, if the spring is an integral part of another component, the spring may be made from plastic because it can be injection molded with the other part.",
"An advantage of this is that it may be possible to reduce costs.",
"Alternatively, in using a metal spring, the element which the spring is part of can be cast around it.",
"This may be done by a simple injection casting process.",
"For example, the spring may be integral with the re-settable element or integral with a supporting ring which may be provided as a separate part between the spring and retaining element, or integral with the retaining element which pushes on the product container and/or comprises an axial stop.",
"Another option is for the retaining element, spring and re-settable element to be of an integral design.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0026] FIG. 1 is a cross-sectional view illustrating a proximal (rear) part of an embodiment of an injection device in accordance with the present invention, [0027] FIG. 2 is a perspective view of an embodiment of a housing part with a guide track for a bayonet lock and an inserted bayonet sleeve, [0028] FIG. 3 is a perspective view of the bayonet sleeve illustrated in FIG. 2 , [0029] FIG. 4 is a perspective view of the bayonet sleeve illustrated in FIG. 3 with a locating element inserted in it, [0030] FIG. 5 is a perspective view of a bayonet sleeve and product container holder, which is moved axially into a fixed torque-transmitting engagement, [0031] FIG. 6 is a perspective view of an output element with a flange and spring element, [0032] FIGS. 7A and 7B are, respectively, an exploded diagram and a perspective view of one embodiment of a brake mechanism in accordance with the present invention, [0033] FIG. 8 is a perspective, exploded diagram of another embodiment of a brake mechanism in accordance with the present invention, [0034] FIG. 9 is a diagram schematically plotting braking force as a function of angular speed, [0035] FIG. 10 is a diagram illustrating braking action as a function of time, [0036] FIGS. 11A and 11B are, respectively, an exploded view and a perspective view of an embodiment of a brake mechanism in accordance with the present invention operating on the principle of an eddy current brake, [0037] FIG. 12 is a perspective view of another embodiment of a brake mechanism in accordance with the present invention operating on the principle of a centrifugal brake, [0038] FIG. 13 is an exploded view of another embodiment of a brake mechanism in accordance with the present invention operating on the principle of a fluidic brake, and [0039] FIG. 14 is a perspective view of a brake housing from FIG. 13 .",
"DETAILED DESCRIPTION [0040] With regard to fastening, mounting, attaching or connecting components of the present invention, unless specifically described as otherwise, conventional mechanical fasteners and methods may be used.",
"Other appropriate fastening or attachment methods include adhesives, welding and soldering, the latter particularly with regard to the electrical system of the invention, if any.",
"In embodiments with electrical features or components, suitable electrical components and circuitry, wires, wireless components, chips, boards, microprocessors, inputs, outputs, displays, control components, etc.",
"may be used.",
"Generally, unless otherwise indicated, the materials for making embodiments of the invention and/or components thereof may be selected from appropriate materials such as metal, metallic alloys, ceramics, plastics, etc.",
"Unless otherwise indicated specifically or by context, positional terms (e.g., up, down, front, rear, distal, proximal, etc.) are descriptive not limiting.",
"Same reference numbers are used to denote same parts or components.",
"[0041] The injection device illustrated in FIG. 1 comprises a drive unit, which, in some embodiments, can be used more than once, and a product container 27 connected to it, which is accommodated in a sleeve-shaped product container holder 16 which can be used multiple times, for example, and which can be secured to the drive unit with the aid of the product container holder 16 .",
"The product container 27 can be removed from the injection device after it is empty, disposed of and replaced with a new one.",
"With a view to simplifying the manufacturing and assembly processes, the housing 12 is of a multi-part design comprising housing elements 12 a, 12 b connected to or inserted in it, although in principle, the housing could also comprise a single part.",
"The product container 16 is attached to the drive unit by a bayonet fitting, which is formed by the housing 12 , product container holder 16 and sleeve 50 .",
"The product container holder 16 is covered by a cap 31 , which is fitted on the housing 12 , and can be removed in preparation for using the injection device and then fitted back on it.",
"[0042] FIGS. 2 to 5 illustrate elements of the fixing device provided in the exemplary form of a bayonet fitting.",
"The product container holder 16 has a cam 16 c extending radially outwardly and at its proximal (rear) end face is designed so that it can be connected in a positive fit, i.e. in a fixed torque-transmitting fit, to the distal (forward) end face of the sleeve 50 , as illustrated in FIG. 5 where housing part 12 a has been omitted for illustration purposes.",
"The sleeve 50 has at least one cam 50 c extending radially outwardly, which forms a part of a cam (which may be thought of as comprising cam elements 16 c, 50 c ) for the fixing device.",
"The cam 50 c locates or is positioned in a guide track 12 e formed in the housing 12 , e.g. in housing part 12 a, which has at least one inclined surface 12 g. When the sleeve 50 is moved in rotation, the sleeve 50 moves axially relative to the housing part 12 a as well as moving in rotation, due to the locating cam 50 c. As will be described below, the axial movement of the sleeve 50 results in various advantageous effects.",
"[0043] To fit the product container 27 on the drive unit, it may be introduced into the product container holder 16 via the proximal end.",
"The product container holder 16 is then snap-fitted onto the sleeve 50 by an axial movement resulting in a fixed torque-transmitting fit ( FIG. 5 ), so that the cams 16 c are inserted through the opening 12 f ( FIG. 2 ) into the guide track 12 e. FIG. 2 illustrates the bayonet fitting in a locked state without the product container holder 16 .",
"In an unlocked state in which the cams 50 c are disposed in the region of, and axially flush with the openings 12 f, the product container holder 16 can be push-fitted.",
"The cams 16 c and 50 c then lie one against the other and form a common cam ( FIG. 5 ).",
"A rotation of the product container holder 16 causes the sleeve 50 to be driven.",
"Due to the inclined faces 12 g, the sleeve 50 and the product container holder 16 are also moved axially.",
"At the end of the rotation, i.e. on reaching the locked position, the common cam (comprising cam elements 16 c, 50 c ) is disposed in the region 12 h of the guide track 12 e in which the two cams 16 c and 50 c are axially clamped together by the sides of the guide track 12 e. To this end, the axial width of the guide track in the region 12 h is approximately as wide as that of the joint cams 16 c, 50 c. [0044] As illustrated in FIG. 4 , a guide sleeve 26 is accommodated in the sleeve 50 , which may also be thought of and/or referred to as the bayonet sleeve.",
"The guide sleeve 26 is connected to the housing 12 so that it can not rotate but can move axially and is connected to the bayonet sleeve 50 so that it can rotate but can not move axially.",
"As a result, when the bayonet sleeve 50 is moved from the unlocked to the locked position and vice versa, the guide sleeve 26 effects a longitudinally guided movement relative to the housing 12 .",
"[0045] As may be seen from FIG. 1 , a threaded insert 6 is connected and/or latched to the guide sleeve 26 so that it can not rotate or move axially.",
"The threaded insert 6 and guide sleeve 26 may be thought of and/or referred to as a locating element (comprising insert and sleeve elements 6 , 26 ).",
"The threaded insert 6 has an internal thread 6 a in which the external thread 2 a of an output element 2 , which might also be called a plunger rod in this example, is guided so that when the output element 2 is rotated, it is guided by the internal thread 6 a of the threaded insert 6 in the proximal direction or in the distal, i.e. opposite, direction, as it is screwed, depending on the direction of rotation.",
"[0046] On its external face, the output element 2 has a thread 2 a, which is interrupted by two grooves 2 b extending in the axial direction lying opposite one another on the circumference.",
"A coupling sleeve 5 constituting part of a transmission (comprising elements 7 , K 2 , 5 ) has two projections 5 a, 5 b directed radially inwardly lying opposite one another on its distal end which project into the grooves 2 b of the output element 2 .",
"The coupling sleeve 5 is connected to the locating element so that it can rotate but is not able to move axially.",
"Accordingly, the output element 2 is locked to prevent it from rotating relative to the coupling sleeve 5 but is able to move axially relative to the coupling sleeve 5 when it is rotated relative to the locating element.",
"The coupling sleeve 5 is not able to move axially expect for when the product container 27 is being replaced.",
"[0047] A drive shaft 7 provided at the proximal end of the injection device and forming part of the transmission has teeth 7 a extending radially inwardly which constitute a coupling element of the coupling K 2 .",
"When operated, i.e. when an operating element 15 is pushed in the distal (forward or injection) direction, the drive shaft 7 and as a result also the teeth 7 a are moved in the distal direction, as result of which the teeth 7 a locate in the proximal end of the coupling sleeve 5 and establish a fixed torque-transmitting, positive connection.",
"[0048] A spring element or drive spring 3 , which may be provided in the form of a helical spring or clock spring, is connected to the housing 12 by one end via a spring sleeve 8 on the external face of the spring 3 .",
"The spring sleeve 8 is prevented from rotating relative to the housing 12 but is able to move axially.",
"At the other end, the drive spring 3 is connected to the drive shaft 7 .",
"As a result, energy stored in the spring 3 can be output as a rotating movement of the drive shaft 7 relative to the housing 12 .",
"To dispense a product, the energy of the spring element 3 is transmitted via the transmission element in the form of a rotating movement to the output element so that the latter is screwed relative to the locating element in the distal direction, i.e. in the dispensing direction, and pushes the plunger 28 , causing the product to be dispensed from the product container 27 .",
"[0049] To set a product dose to be administered, a user can rotate the dose setting element 9 provided in the form of a dose setting button, which is axially fixed relative to the housing 12 .",
"The dose setting element 9 is coupled with a coupling element 10 via the coupling K 3 so that it is prevented from rotating.",
"The coupling K 3 is formed by webs or grooves or teeth of the dose setting button 9 , which co-operate in a positive fit with webs or grooves or teeth of the coupling disc 10 to establish a coupling which can be released by a movement of the coupling element 10 in the distal direction.",
"The coupling element 10 can be moved and thus released by operating the operating element 15 .",
"When in a state of not being operated, the coupling K 3 is held in a coupled state and the coupling K 2 in an uncoupled state by a spring element 19 , which pushes the drive shaft 7 in the proximal (rear or rearward) direction.",
"During the dose setting operation, the coupling K 3 is coupled, i.e. a rotating movement of the dose setting button 9 is transmitted to the coupling element 10 .",
"The coupling element 10 is connected to the drive shaft 7 so that it can not move axially and can not rotate and could also be an integral part of the drive shaft 7 .",
"The rotating movement of the dose setting element 9 is not transmitted to the coupling sleeve 5 because the coupling K 2 is uncoupled.",
"[0050] When the drive shaft 7 is rotated, the drive spring 3 connected to the drive shaft 7 is tensed.",
"To prevent the dose setting button 9 from being turned back due to the drive spring 3 as it is tensed during the setting operation, a ratchet 11 or a ratchet mechanism, which may comprise a ratchet spring 11 a, e.g. for clamping retaining elements, may be provided between the housing 12 of the injection device, the components of which might, for example, be a mechanical holder 12 a and a mechanical holder 12 b and the dose setting button 9 .",
"The ratchet mechanism may be designed so that a rotation and/or a tensing of the drive spring 3 is possible in only one direction.",
"In some preferred embodiments, however, the ratchet mechanism is designed so that the rotating action is possible in both directions, e.g. tensing and relaxing of the drive spring 3 .",
"Due to the fact of being able to rotate in both directions, a product dose can be both increased and reduced when setting the product dose.",
"A currently set product dose can be read through the window 12 d of a display barrel 4 .",
"[0051] The rotating movement of the drive shaft 7 is also transmitted to the threaded sleeve 13 , which is connected to the drive shaft 7 so that it is not able to move axially or rotate and may also be an integral part of it.",
"The threaded sleeve 13 has at least one groove on its external circumference 13 a in which at least one web 4 a of the display barrel 4 locates so that a rotating movement of the threaded sleeve 13 is transmitted to the display barrel 4 by the anti-rotation coupling, permitting an axial relative movement between the display barrel 4 and threaded sleeve 13 .",
"The display barrel 4 has a thread 4 b on its external face which locates in an internal thread 12 c of the housing part 12 b so that the display barrel 4 is moved due to a rotating movement in the axial direction relative to the housing 12 , e.g. in the distal direction.",
"In some preferred embodiments, the display barrel 4 moves in the distal direction of the injection device (towards the left in FIG. 1 ) during the process of setting and priming the dose by rotating the dose setting button 9 .",
"A marking may be provided on the external face of the display barrel 4 , such as print, a dose display or a scale, which can be read through an opening or a window 12 d in the housing 12 b of the injection device, and the marking of the display barrel 4 is moved relative to the window 12 d. The display barrel 4 has a rotation stop on its distal end acting in the circumferential direction which moves into an abutting contact with a co-operating complementary stop disposed on the housing part 12 a on reaching the maximum dose.",
"The complementary stop is formed by a terminal end of an annular gap of the housing part 12 a. An advantage of using a stop which acts in the circumferential direction rather than an axial stop is that the forces acting on the stop are weaker.",
"The display barrel 4 also has another rotation stop on its proximal end acting in the circumferential direction, which moves into an abutting contact with a co-operating complementary stop on the housing 12 b on reaching a minimum dose.",
"The complementary stop is formed by the proximal end of the thread 12 c. [0052] Once the dose has been set and the drive spring 3 primed by rotating the dose setting button 9 , the setting operation is complete.",
"In some preferred embodiments, the dose is primed as the spring 3 is tensed.",
"To correct or adjust the dose, the dose setting button 9 simply has to be rotated in the opposite direction, e.g. to reduce a dose which might have been set too high.",
"In some embodiments, the ratchet 11 may be designed as illustrated in FIGS. 14 and 15 of patent application PCT/CH2007/000243 and/or US Publication 2009/0254035, the teachings of which are incorporated herein by reference.",
"[0053] During the dispensing process, which is triggered by depressing the push button 15 , the display barrel 4 is rotated back in the opposite direction and is moved back in the proximal direction due to the thread engagement with the internal thread 12 c of the injection device (to the right in FIG. 1 ).",
"As this happens, it reaches a stop of the display barrel 4 acting in the circumferential direction on the housing of the injection device, e.g. on the housing part 12 b. In an unbraked dispensing movement in which the threaded rod 2 is moved in the distal direction without any opposing force, e.g. when no product container has been inserted, this operation may result in too high a strain and, in an extreme situation, deformation or even damage to the display barrel 4 or co-operating part 12 b. A brake mechanism (e.g. comprising brake elements, e.g. shoe halves and disc 17 , 18 ) acting on the driving movement is therefore provided, which will be described below.",
"[0054] The coupling K 1 , comprising the coupling element acting as a lock sleeve 14 and the coupling sleeve 5 , is used to couple the coupling sleeve 5 with the housing 12 so that it can not rotate in specific operating modes or to release it to permit a rotation relative to the housing 12 .",
"The coupling K 1 is uncoupled when the product container 27 is being replaced to enable the output element 2 to be pushed back or screwed in the proximal direction again and to enable the output element 2 to be screwed in the distal direction while product is being dispensed.",
"The coupling K 1 is coupled when the product container is attached to the drive unit and the operating element 15 is not being operated.",
"The coupling K 1 is provided in the form of teeth on the external face of the coupling sleeve 5 , which mesh in teeth on the internal face of the lock sleeve 14 .",
"As a result, the coupling sleeve 5 is prevented from rotating relative to the lock sleeve 14 .",
"The lock sleeve 14 is mounted in the injection device so that it can not rotate but can move axially relative to the housing 12 and the coupling sleeve 5 .",
"[0055] During a dispensing operation, the threaded sleeve 13 is moved in the distal (forward or injection or delivery) direction by operating the operating element 15 .",
"As this happens, the threaded sleeve 13 pushes on the bearing 29 , which is provided in the form of a ball bearing in this example but may also be a simple slide bearing, so that the bearing 29 pushes against the lock sleeve 14 , thereby moving it in the distal direction for a dispensing operation, and holds it in a distal position during a dispensing operation.",
"The coupling element 14 is therefore disposed distally of the projections of the coupling sleeve 5 for the coupling K 1 .",
"As a result, the coupling K 1 remains uncoupled for the duration of the dispensing operation.",
"[0056] When the operating element 15 is operated, the couplings K 1 , K 2 and K 3 operate as follows.",
"By depressing the push button 15 seated on the coupling element 10 and/or drive shaft 7 , the coupling element 10 is pushed in the distal direction together with the push button 15 and the drive shaft 7 .",
"As a result, the coupling K 2 is coupled so that the drive shaft 7 is prevented from rotating relative to the coupling sleeve 5 .",
"The coupling K 1 is then uncoupled due to the movement of the lock sleeve 14 , against which the threaded sleeve 13 connected to the drive shaft 7 pushes via the axially displaceable bearing 29 .",
"Alternatively, the couplings K 1 and K 2 may be connected in the reverse sequence.",
"[0057] Once K 2 is coupled and K 1 is uncoupled, the coupling K 3 is also uncoupled due to the movement of the coupling element 10 relative to the dose setting button 9 .",
"The coupling element 10 , which is connected to the drive shaft 7 , is able to rotate relative to the housing 12 once the coupling K 3 is uncoupled.",
"The energy or force stored in the drive spring 3 during priming can be transmitted to the drive shaft 7 .",
"Accordingly, a torque is applied to the drive shaft 7 , which is transmitted by the coupled coupling K 2 to the coupling sleeve 5 , which rotates in unison with the drive shaft 7 and transmits this rotating movement to the output element 2 , which is coupled with the coupling sleeve 5 so that it can not rotate.",
"The output element 2 , provided in the form of a threaded rod in this example, converts the rotating movement into an axial movement in the distal direction due to the thread engagement 2 a, 6 a with the locating element (comprising elements 6 , 26 ), so that the flange 1 provided on the distal end of the threaded rod 2 , which may also be construed as part of the output element, is moved in the distal direction of the injection device.",
"[0058] Since, during the product dispensing operation, the threaded sleeve 13 moves in the direction opposite that in which it moves during priming, the display barrel 4 likewise moves in the direction opposite that of the priming operation.",
"[0059] In the normal situation, i.e. when a pre-set product dose has been fully dispensed, the dispensing operation and the movement of the output element 2 in the distal direction continues until the display barrel 4 makes contact with the above-mentioned stop acting in the circumferential direction.",
"In some embodiments, this happens when the value which can be read through the window 12 d has been rotated back to 0 .",
"[0060] In the situation in which the user of the device releases the operating element 15 as the product is being dispensed, the couplings couple in the order which is the reverse of that in which they uncoupled or coupled during operation.",
"The product dispensing operation is interrupted, as a result of which the value may be seen through the window 12 d represents the amount still to be dispensed had the pre-set dose been fully dispensed.",
"The product dispensing operation can be continued by depressing the operating element 15 again, and dispensing can be stopped again by releasing the operating element 15 or the user can wait until the product has been fully dispensed.",
"[0061] In the situation in which the product container contains less product than the maximum dose indicated on the display barrel, the injection device based on this example has an additional device for limiting the maximum dose which can be set for the last time, to prevent the possibility of a bigger product dose being set than that which is still in the container.",
"To this end, a traveller 30 is provided, which at least partially surrounds the coupling sleeve 5 and locates with the coupling sleeve 5 in such a way that the traveller 30 is not able to rotate relative to the coupling sleeve 5 but is able to move axially.",
"The traveller 30 also locates or is positioned by a thread on its external circumference that engages with an internal thread of the threaded sleeve 13 .",
"This arrangement causes an axial movement of the traveller 30 when there is a relative rotation between the threaded sleeve 13 and coupling sleeve 5 , and when there is no relative rotation the traveller 30 does not effect an axial movement.",
"When setting a product dose, the threaded sleeve 13 turns relative to the coupling sleeve 5 so that the traveller 30 moves in the proximal direction.",
"During dispensing, on the other hand, no relative movement takes place between the coupling sleeve 5 and threaded sleeve 13 due to the coupled engagement of the coupling K 2 .",
"Accordingly, the traveller does not move.",
"After setting doses and dispensing product several times, the traveller 30 moves into an abutting contact with the drive shaft 7 , so that it is no longer possible to increase the dose, even if the display would actually permit this.",
"[0062] The user can replace the product container 27 with a new one.",
"To this end, the product container holder 16 may be removed by rotating the drive unit relative to the housing 12 .",
"As the product container 27 is moved from the secured position into the non-secured position, e.g. as the bayonet fitting is released, the locating element is moved together with the output element 2 and the coupling sleeve 5 in the distal direction relative to the housing 12 and to the coupling element 14 , thereby releasing the coupling K 1 .",
"The projections of the coupling sleeve 5 pointing radially outwardly to establish the coupling K 1 are now disposed distally of the coupling element 14 .",
"The output element 2 can now be screwed into the drive unit with a relatively slight force acting in the proximal direction because the thread of the output element is not retained by friction.",
"As the output element 2 is screwed back, the coupling sleeve 5 is turned relative to the threaded sleeve 13 and so in the direction opposite that during product dispensing, causing the traveller 30 to be pushed back in the distal direction again.",
"The screwing-back operation may take place against the force of a spring element, at least across a part of the total distance, which tries to push the output element in the distal direction, for example.",
"The spring element may act or be disposed between the output element 2 and the drive shaft 7 for example.",
"Other possible spring elements will be described below specifically with reference to FIG. 6 .",
"It is generally preferred if the force of such a spring element is weaker than the force needed to produce an interaction via the plunger from the output element 2 onto the product.",
"[0063] Also during the process of removing the product container 27 , the retaining element 25 used to secure the product container 27 in the product container holder 16 is pushed in the distal direction by the spring 19 until it makes contact with the locating element 6 , 26 .",
"This contact prevents the spring 19 from fully relaxing when the product container 27 is removed.",
"This is of advantage because the spring 19 should be able to apply sufficient force to hold the coupling K 3 in a coupled engagement even when a product container 27 has been removed.",
"[0064] By virtue of another aspect, a spring-mounted flange may be used, as illustrated in FIG. 6 for example.",
"[0065] After replacing the product container 27 , e.g. an ampoule, capped vial or the like, the user is prompted to proceed with priming, as may be described in operating instructions.",
"This is useful on the one hand because there may be air in the product container 27 and on the other hand because the output element 2 may have been previously pushed fully into the drive unit and a certain amount of clearance may have been created between the plunger 28 and the flange 1 due to the different level to which the product container 27 is filled.",
"[0066] FIG. 6 illustrates an output element 2 with a flange 1 attached to its front or distal end, which is non-displaceably connected to the threaded rod.",
"Disposed between the flange 1 and the threaded insert 6 illustrated in FIG. 6 is a spring element 38 , which may be provided in the form of resilient arms 38 a extending out at an angle, for example.",
"These resilient arms 38 a may be secured to the flange 1 or/and to the threaded insert 6 .",
"Another option would be to injection mold a suitable elastomer onto the flange 1 or/and onto the threaded insert 6 .",
"After a new product container 27 has been inserted, a clearance may occur between the flange 1 and the plunger 28 , which may be attributable to a difference in the level to which product containers 27 have been filled when full, given that they have a certain tolerance.",
"[0067] After pushing in the flange 1 connected to the threaded rod 2 , the flange 1 based on the embodiment illustrated in FIG. 1 lies directly against the threaded insert 6 .",
"[0068] In the embodiment illustrated in FIG. 6 , the at least one spring element 38 has pushed the flange 1 away from the threaded insert 6 in the distal direction by a predefined distance.",
"This means that when a product container 27 has been inserted or while a product container 27 is being inserted, the flange 1 will move into contact with the proximal end of the plunger 28 , even if the plunger 28 is pushed into the product container 27 by differing distances caused by manufacturing tolerances of different product containers.",
"Conventional means for eliminating the clearance between the flange 1 and plunger 28 are therefore no longer absolutely necessary and may even be dispensed with, for example.",
"[0069] As may be seen from FIG. 1 , the injection device, e.g. the drive unit, comprises a brake (which may be thought of as comprising brake elements or components 17 , 18 ) which decelerates a rotating part, in this example the transmission element or/and the driving movement.",
"If conventional injection devices are used incorrectly, i.e. if no product container has been inserted, but the device is nevertheless operated, there is a risk of placing too high a strain on or even damaging the components of the injection device.",
"When a product container 27 is inserted, the forces and movements which occur are damped by the viscosity of the product during the product dispensing operation.",
"In the absence of a product container, there is no such damping effect.",
"It is the brake in accordance with the present invention which is used for this purpose, thereby preventing excessive strain.",
"[0070] FIGS. 7A, 7B and 8 are diagrams on a larger scale illustrating embodiments of a brake mechanism suitable for the device illustrated in FIG. 1 , e.g. a first and second embodiment, respectively, each of which operates in a similar manner.",
"The first embodiment illustrated in FIGS. 7A, 7B has two brake shoe halves 17 latched to one another so that they can not rotate and so that they can also not move axially, which have profiled portions directed toward one another, between which an annular gap is formed in which a brake disc 18 is accommodated.",
"The annular gap is of a defined width and, in an alternative arrangement, the brake shoe halves could move axially relative to one another.",
"The brake shoe 17 could be of an integral design.",
"The brake disc 18 is accommodated so that it can not rotate relative to the housing 12 but can move axially, due to the profiled external circumferential surface of the brake disc locating in a profiled inner circumferential surface of the housing part 12 b. At least one brake shoe half 17 or the entire brake shoe is mounted at least so that it can not rotate in the drive train or transmission element.",
"The sleeve-shaped brake shoe 17 has projections pointing radially inwardly, which locate in a matching profile of the drive sleeve 7 .",
"The brake disc 18 is able to move between the brake shoe halves 17 .",
"The brake disc 18 is mounted so that it can not rotate, e.g. is guided in a groove, and so that it is able to move axially in the injection device or housing part 12 b. The brake disc 18 is toothed on the top and bottom face with teeth 18 a, 18 b on the end face projecting circumferentially in both directions and having an identical or different tooth height ZH, and is mounted or displaceably clamped between the threaded sleeve 13 and the brake shoe 17 , e.g. with a small clearance of approximately a tooth size or tooth height ZH or bigger, the latter having co-operating complementary teeth 13 b respectively 17 a, e.g. with a corresponding or identical tooth height ZH.",
"[0071] Due to the fixed torque-transmitting connection between the transmission element (which, again, may be thought of and/or referred to as comprising elements 7 , K 2 , 5 ) during a dispensing operation or when what may be thought of and/or referred to as “firing blank,” i.e. when no product container has been inserted, the brake shoe 17 is moved in rotation relative to the brake disc 18 .",
"When this happens, the disposition of the brake shoe teeth 17 a, 17 b ensure that the brake disc 18 oscillates axially between the threaded sleeve 13 and the brake shoe 17 .",
"As a result, the distal teeth 18 a and proximal teeth 18 b of the brake disc 18 move alternately into contact with the co-operating complementary teeth 17 b and 17 a. Due to one or more of the resultant friction, elastic deformation and the oscillating mass, a corresponding loss occurs, thereby limiting the maximum angular speed o of the rotating parts 13 and 17 .",
"[0072] The embodiment illustrated in FIG. 8 operates on a similar principle, the difference being that one of the two brake shoe halves and/or its end-face tooth profile is formed by the transmission element or the threaded sleeve 13 connected to the transmission element so that it cannot rotate.",
"A fixed, defined distance may be provided between the profiles 17 a and 13 b, or alternatively a variable distance, because the brake shoe half 17 is able to move axially relative to the threaded sleeve 13 .",
"Due to the spring 19 , the profiles 13 b and 17 a can be pushed toward one another so that they move into a meshing contact with the profiles 18 a and 18 b. [0073] Due to the vibration or oscillation of the brake disc 18 between the threaded sleeve 13 and brake shoe 18 which increases with the angular velocity co, the braking force increases disproportionately as the angular velocity co increases, so that the curve BS of braking forces schematically illustrated in FIG. 9 can be achieved.",
"[0074] FIG. 9 is a schematic illustration plotting the curve of the braking force which can be achieved by a brake mechanism in accordance with the present invention, from which it may be seen that the braking force rises to an increasing degree with the angular or rotational velocity co.",
"In some preferred embodiments, the braking force is relatively low or zero up to the maximum permissible angular velocity ω max and rises sharply with effect from the maximum permissible angular velocity ω max .",
"[0075] FIG. 10 illustrates the angle of rotation of the display barrel 4 as a function of time, which is able to effect three full revolutions (3×360°) in the embodiments illustrated as an example.",
"As may be seen from FIG. 10 , the display barrel 4 has completed three full revolutions after the time t non-braked , which is shorter than the time t invention in the case of a decelerated rotating movement of the display barrel 4 during which the angle of rotation increases linearly as a function of time.",
"[0076] Due to the braking force generated by the oscillating brake disc 18 , the maximum possible angular velocity ω max of a dispensing movement can be reduced or limited so that the backward-rotating display barrel 4 is able to move into an abutting contact with the stop acting in the circumferential direction or the housing part 12 b at only a maximum speed predefined by the brake.",
"If the brake is designed accordingly, the maximum possible contact speed of the display barrel 4 is so low that there is little chance of deformation or damage occurring due to the impact.",
"Other brake mechanisms may also be used as an alternative to a brake disc 18 oscillating between the threaded sleeve 13 and brake shoe 17 .",
"[0077] For example, as an alternative or in addition, the brake may be based on another embodiment in the form of a centrifugal brake as illustrated in FIG. 12 .",
"In this case outwardly displaceable brake shoes 41 are mounted on the transmission element or/and the drive shaft 7 and/or another part which rotates with the drive shaft 7 , for example the coupling element 10 , the threaded sleeve 13 or the display barrel 4 , which have a mass and which effect the same rotation as the rotating part.",
"The brake shoes 41 may, but need not necessarily, be inwardly or outwardly biased by a spring.",
"The brake shoes may be pivoted or moved radially outwardly by the centrifugal force to move into a braking engagement with a sleeve 42 , for example the housing 12 .",
"In this embodiment, pins 40 or fasteners extending radially outwardly are provided, the ends of which are provided with brake pads 41 biased by the spring, for example.",
"When the rotation speed of the non-braked or only partially braked rotating element is sufficiently high, the brake pads 41 are moved radially outwardly by the centrifugal force, optionally also assisted by the spring-biased support, and can move into contact with an outer static sleeve 42 , thereby producing the desired braking effect due to friction.",
"The outer static sleeve may also be formed by the housing 12 or housing part 12 b. [0078] In another embodiment illustrated in FIGS. 11A and 11B , the brake may be provided in the form of an eddy current brake 20 , in which case a brake disc 21 may be connected to a rotating part which has to be decelerated, for example the transmission element, drive shaft 7 , threaded sleeve 13 or display barrel 4 , and the elements interacting with the brake disc may be connected to the housing or an element fixedly disposed on the housing or to an element rotating relative to the brake disc.",
"[0079] In some preferred embodiments, the brake disc 21 is made from a good electrical conductor, such as pure aluminium or copper, for example.",
"Rare earth alloys may be used as the material for the axially magnetised magnets 22 , neodymium for example.",
"The permanent magnetic field may be linked by a magnet yoke 23 made from iron to the air gap, where it extends through the brake disc 21 as vertically as possible.",
"The braking force is created by the surface and flow density in the air gap and the rated current in the brake disc 21 , for which purpose the surface should be as large as possible, the air gap should be as small as possible and the disc thickness should be as big as possible.",
"The braking torque occurs over the averaged radius (working radius).",
"Brakes may be designed with several magnet systems which act on a disc 21 .",
"[0080] The usual approximation calculations are used to calculate the current density, braking power and hence braking torque of an eddy current brake.",
"Leaving aside the effect of the air gap, it is assumed that there will be a standard cylindrical magnetic flow and it is stipulated as a condition that the pole diameter should be sufficiently small compared with the radius of the disc 21 .",
"At high speeds, the approximation is inaccurate, among other reasons because the magnetic fields caused by the eddy currents cause a not inconsiderable feedback and hence non-linearity.",
"[0081] In some preferred embodiments, the magnets 22 and the magnet yoke 23 are connected to the housing 12 of the injection device or the housing part 12 b or another non-rotating part to be able to generate the desired eddy current braking effect of the brake disc 21 .",
"[0082] In another embodiment illustrated in FIGS. 13 and 14 , the brake may be provided in the form of a fluidic or hydrodynamic brake.",
"If a standard fluid is used as the braking medium, the linear braking curve FB indicated in FIG. 4 can be obtained for the eddy current brake.",
"However, if the intention is to achieve a braking force which rises more sharply as a function of angular velocity w, so-called non-Newtonian fluids may be used, as a result of which, unlike a Newtonian fluid, the viscosity does not remain constant but increases when a shearing force acting on the fluid is increased, which is the case as the speed increases.",
"These are what are known as anomalous viscous fluids.",
"[0083] In the case of the fluidic brake, the braking force is generated by two fluid surfaces moving against one another.",
"In particular, the braking force is generated by a fluid volume which is sheared by a relative movement.",
"The shearing stresses which occur during such movements correspond to the braking force.",
"The volume is provided in the form of a chamber split into two parts 45 a, 46 a, in which the fluid is disposed.",
"One chamber part 46 a is disposed in a rotating part 46 and the other chamber 45 a is disposed in a part 45 relative to which the rotating part 46 is able to rotate.",
"The part 46 may be connected so as to rotate in unison with the drive shaft 7 or to the transmission element or another part which rotates when product is being dispensed.",
"The part 45 rotates in unison with at least the housing 12 or a stationary part on the housing.",
"Furthermore, the part 45 may be able to move axially or may be axially immobile relative to the housing 12 .",
"The sleeve-shaped part 45 may be thought of and/or referred to as a brake housing and the part 46 mounted in the sleeve 45 as a brake shaft.",
"When the brake is in the assembled state, the fluid chamber halves 46 a distributed axially around the external circumference of the brake shaft are axially on a level with the fluid chamber halves 45 a distributed around the internal circumference of the brake housing.",
"More, the same number or fewer fluid chamber halves 45 a may be provided than 46 a. In the assembled state, a slim gap is disposed between the internal diameter of the brake housing 45 and the external diameter of the brake shaft 46 in the region of each of the fluid chamber halves 45 a, 46 a, which may be dimensioned so that fluid is conveyed into the gap or no fluid or virually no fluid is conveyed into the gap when the brake shaft 46 is rotating relative to the brake housing 45 .",
"The brake housing 45 may be axially sealed at both ends with sliding seal elements 47 so that no fluid is able to escape from the brake.",
"The seal elements 47 may be provided in the form of a lid.",
"The lid may be provided as a separate part or serve as the coupling shaft, for example.",
"[0084] Embodiments of the present invention, including preferred embodiments, have been presented for the purpose of illustration and description.",
"They are not intended to be exhaustive or to limit the invention to, the precise forms and steps disclosed.",
"The embodiments were chosen and described to illustrate the principles of the invention and the practical application thereof, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.",
"All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth they are fairly, legally, and equitably entitled."
] |
REFERENCES TO RELATED APPLICATIONS
This application is a continuation in part for the application with Ser. No. 08/075,147, which was filed on Jun. 10, 1993 now U.S. Pat. No. 5,381,704. The earlier filing date of this application is hereby claimed.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the Bearing Tooth Gear and related gear types, with rotatable gear teeth and in particular the attachment methods, bearing placement, constructive materials and specific design types and configurations of said tooth structures.
2. Description of Prior Art
The design and manufacture of conventional gears, is an old and a somewhat antiquated technology or more accurately, an art. The world's gear manufactures still use the same designs, construction methods and materials, that have changed little for the past century, in particular, cantilever tooth structures, which can be of a complex nature or geometry, such as, the Spiral Bevel, Helical, Crossed Helical, Hypoid, Spiroid, Helicon are machined into metallic alloys and then hardened by various heat treating processes. These teeth are designed to be in sliding contact, with a thin lubricant film separating the mating teeth.
There are numerous advantages to be had by replacing the sliding contact, of the conventional gear, with the rolling contact, of the Bearing Tooth Gear. The obvious energy savings due to the difference in sliding versus rolling friction, is just the start. Some of the improvements of the Bearing Tooth Gear, follow. Field servicing is now an option, servicing is less costly, increases the number of candidate manufacturing materials, lighter weight structures can be made, increases the number of manufacturing processes that can be utilized, tighter tolerances easier to maintain on tooth geometry and tooth placement, stocking of standard tooth types is cost effective, decreases overall cost in manufacturing, quicker build and delivery times of replacement parts, enlarges operating envelope, reduces operating noise, reduces lubricant fluid drag, greater tolerance to shock loads, more tolerant of foreign object contamination, smaller and more highly loaded gear sets can be made.
Rotatable gear teeth have been presented in past patents, such as, Stanley (U.S. Pat. No. 277,802; issued May 15, 1883): Saladee (U.S. Pat. No. 486,055; issued Nov. 8, 1892): Jamieson (U.S. Pat. No. 596,884; issued Jan. 4, 1898): Jamieson (U.S. Pat. No. 613,148; issued Oct. 25, 1898): Jamieson (U.S. Pat. No. 620,074; issued Feb. 21, 1899): McCormick (U.S. Pat. No. 633,470; issued Sep. 19, 1899): Froelich (U.S. Pat. No. 1,159,486; issued Nov., 9, 1915): Wojtowicz (U.S. Pat. No. 2,792,715; issued May 21, 1957): Gilbert (U.S. Pat. No. 3,608,392; issued Jun. 15, 1970); Grayson (U.S. Pat. No. 3,845,670; issued Nov. 5, 1974): Knutson (U.S. Pat. No. 4,093,036; issued Jun. 6, 1978): Fujita (U.S. Pat. No. 4,541,297; issued Sep. 17, 1985): and Kerkhoff (U.S. Pat. No. 4,879,920; issued Nov. 14, 1989).
While some of the above mentioned patents touch on attributes such as the ability to replace worn parts (U.S. Pat. Nos. 277,802; 596,884; 1,159,486; 2,792,715) diminishing friction and wear (U.S. Pat. Nos. 486,055; 596,884; 613,148; 633,470; 4,879,920) silent operation (U.S. Pat. Nos. 1,159,486; 3,608,392) backlash elimination (U.S. Pat. Nos. 3,608,392; 4,879,920), none of these patents explore the fully potential of the technology nor the means to obtain that potential.
Items such as, the option to exercise tight, yet more cost effective, tolerance control during manufacture yet being more adaptive to manufacturing inaccuracies, or the fact that fewer and larger, more load capable, gear teeth can be employed. Or the option of being able to have quick release Bearing Tooth packs or assemblies, which allow teeth to be replaced with greater ease. Or the option of employing displacement and shock tolerant materials and structures such as elastomeric and/or plastics and/or fluid filled and/or gas filled teeth and/or similar materials and/or structures for the zone that receives the bearing packs, within the support housings and the option of using cheaper and/or light weight load bearing materials for these structures, all lead to the following attributes; gear sets that are tolerant of higher shock loads, much quieter gear sets due to greater sound adsorption and vibrational dampening capabilities, elimination of high stress point loading, less massive structures for weight critical applications (eg. aerospace systems), greater capability to tolerate adverse operating environments, such as high dirt, high grit, high moisture and even corrosive environments. And finally, by not limiting the support bearings to the interior of the rotatable tooth, gives the option of constructing a Bearing Tooth, which possesses greater structural continuity and greater beam cross-section, thereby giving greater bending and torsional load capacity.
SUMMARY OF THE INVENTION
To elaborate upon the previously mentioned objects, all of the benefits or attributes of this invention are a result of the following change of mind set, that being, the substitution of rolling contact for sliding contact, the latter of which, is present in all conventional gear sets. The rolling contact of the Bearing Tooth Gear allows a number of capabilities to be added to its list of attributes. Capabilities which at best, are difficult to achieve if not impossible with conventional gear sets, where sliding contact is the method of tooth engagement.
The rolling contact of the Bearing Tooth gear will improve the energy efficiency of a machine's gear train because of several factors. The obvious fact that rolling friction is less than sliding friction, even if the sliding surfaces are lubricated, can be verified, by checking just about any lubrication handbook but there are other ways that conventional gear efficiency is affected. One lose factor that is often ignored is the drag produced by the fluid lubricant, which is required for the conventional gear set. It is often thought that this drag effect is of little consequence even when employing heavy weight or high viscosity lubricants. Normally this is the case but have a machine operate in a low temperature environment and the viscous drag effect, can become substantial. Consider the example of a cold winter day in the Midwest, where perhaps the temperature drops to -10 degrees Fahrenheit. It is not difficult to envision what happens to the oil, in the differential of ones car, it turns to a virtual glue and this thicken lubricant will substantial impede the rotation of the gear set. Now consider the fact that perhaps 30 million commuters are in this low temperature region and are experiencing this lubricant drag effect, the cumulative energy loses would be huge and this scenario happens more than once a year. The Bearing Tooth Gear differs, in that, a Bearing Tooth Gear set, need not be immersed in a lubricant because of the rolling action and materials and structures that the Bearing Tooth can employ. The only location where lubrication is required for a Bearing Tooth assembly is within the support bearings of the individual tooth and when one considers quantity of lubricant and size of the structures, the fluid drag would truly be of little consequence.
While some conventional gear designers have attempted to employ some measure of field servicing, by having removable tooth tracks of perhaps 8 to 10 gear teeth, there are problems with obtaining adequate tolerances with this method. If a facility undertakes the machining of a 10 tooth gear track, with its complex geometry, it soon finds the difficult in holding tight tolerance control on such a intricate and complex part. This problem expands, when for example, 8 of these tracks must be mated with a support housing. Now a reasonable degree of tolerance control must be exercised with the positional locating and with the three axis orientation, of these parts, relative to the gear housing. To have a conventional gear set with high speed capability and high transmission efficiency, requires tight tolerance control. A general manufacturing rule is, the tighter the tolerance control, the higher the price of manufacture.
In contrast, the Bearing Tooth Gear has a simpler geometry, with cylindrical and cylindrical like (eg. bell shaped), cross sections which allow the very high tolerance control of a turned part. Also, the accurate locating of the individual Bearing Tooth, in the support housing, is an easier task for several reasons. One of the more obvious reasons is, the three axis angular alignment requirement, of the conventional gear tooth, is reduced to, two axis, with the Bearing Tooth Gear. There is no clocking tolerance or control requirement for the third axis, or the axis of rotation, for the individual Bearing Tooth. Since the third axis is the axis a Bearing Tooth spins on and is not a set feature, as with a conventional gear, there is no need to exercise tolerance control on this parameter. Also, the relatively simplistic structure of a receptacle hole, for an individual Bearing Tooth assemble, is a feature where high tolerances are much easier to obtain versus the machining of a conventional gear tooth, with its complex geometry and its stringent placement and orientation requirements. Lastly, even though a more accurate structure can be obtained with the Bearing Tooth Gear, it does not require the same stringent tolerance control of the conventional gear. Because of the options available to the Bearing Tooth Gear, such as the use of displacement tolerant materials (e.g. elastomers), the Bearing Tooth Gear can accommodate greater manufacturing inaccuracies.
Another point to consider is that most of the conventional gear's failure modes are inapplicable to the Bearing Gear (eg. pitting, scoring) and some are greatly reduced (eg. wear). Thus these failure types which for the conventional gear, are driven by large tooth size, do not limit the tooth size of the Bearing Gear. This gives the option of employing larger gear teeth with higher individual tooth load capacity, which in turn allows the use of smaller more compact gear housings which are capable of transmitting the same torque loads as a conventional gear with its large diameter and low tooth loads (eg. Torque=Tooth Load×Housing Radius). Not only can the tooth structure be larger for the Bearing Tooth Gear but fewer teeth are required to cover a given circumference, thus there are fewer structures to manufacture and therefore fewer structures to exercise tolerance control on.
All of these features reduce cost and add to the practicality of having replaceable gear teeth which in turn greatly reduces any future repair costs. With some of these roadblocks and obstructions removed from the premise of replaceable gear teeth, further refinements can still be made, in the methods with which these Bearing Teeth are attached, to the main gear housing.
To simplify the repair and replacement of damage or worn Bearing Teeth, complete Bearing Tooth packs or assemblies could be made, which contain a load and environment capable bearing set, of the designers choice. This could include one or a combination of the following bearing types; ball bearings single or multi-row, angular-contact ball bearings, ball bushings, roller bearings, cylindrical roller bearings, needle bearings, tapered roller bearings, spherical roller bearings, fluid film bearings, journal bearings and finally thrust bearings of the ball, straight-roller or tapered-roller type, could be used in conjunction with any of the above radial load type bearings. The proper bearing type or types could be selected to accommodate all projected operating speeds and all projected axial, bending, shear and torsional loads. These tooth packs would have seals to contain all internal lubricants and assure complete environmental insolation. These packs could then have a myriad of attachment methods to the gear housing, external threading, tapered slip joint, straight slip joint, pin or bolt restraints, side slip joint, side access ports.
With these totally self contained Bearing Tooth assemblies not only would the act of repair and servicing be greatly simplified but the individual part cost will decrease due to the mass production aspect, of families of varying Bearing Tooth types. This mass production aspect can apply to smaller conventional gears, where perhaps 1,000 one inch in diameter spur gears are manufactured but this option soon becomes less practical as the gear size increases and the number of applications decrease. For instance, if a manufacture has an order for 3 ten foot in diameter conventional gear types, that manufacture will not build any spares because it maybe ten years before another gear of this type is purchased, if ever. If the same order was place for 3 Bearing Tooth Gears, with 30 teeth per gear, it could be cost effective to build 100 or 150 teeth, where the spares could be utilized for future orders of different gear types, that could utilized this standard tooth type (eg. perhaps a 5 foot in diameter gear could use the Bearing Teeth from this tooth family).
The rolling contact aspect, of the Bearing Tooth Gear, again comes into play with this next manufacturing option and that is, an increase in the list of candidate materials and in the design choices for the tooth and housing types, that the designer can now employ. The conventional gear designers are limited in types of materials and processes they can utilize, because of the contact zone environment, with its high contact and shear loading and the high bending stresses experienced by these relatively, small highly loaded cantilever beams. These operating characteristics of the conventional gear, will cause all but a few materials to fail. So except for the occasional Nylon or Brass gears with their low load and operational speed limits, the material of choice is a harden steel alloy. The steel alloys used in the construction of most gear types are heavy, brittle, difficult to machine and both costly as a material and costly to process.
A comparison to systems that use rolling structures of varying materials and configurations, could prove useful here. So as an example the automobile, with its elastomeric, pneumatically filled structures that interface with the road surface (eg. tires), which among other functions, contributes to the shock dispersion or diffusion capability of the suspension system, an elastomeric, pneumatically filled Bearing Tooth could provide the same capability to a gear set. Again, the design of an individual Bearing Tooth can be much like an automobile tire, where there are various design choices available for the tread and the ply designs (eg. radial), which among other functions, control wear patterns and modulating or decreasing the operational noise signature of a gear set. Like the tire designer, the gear designer can choose various rubber compounds that offer varying rolling friction (eg. traction) and wear performance. Bearing Teeth could be designed to handle high loads with minimal deflection or displacement at the contact point. By following the tire model once again, the technology of the solid rubber tire of the industrial forklift or the high pressure tire of the Navy's, carrier based, aircraft, could be employed in the design of Bearing Teeth that require high load, minimal displacement, operating characteristics. And some applications may require the high pressure pneumatic performance but a high pressure hydraulically filled Bearing Tooth could provide similar performance, yet offer a more benign failure behavior. Finally, each Bearing Tooth would have a support structure that interfaces with the shock load tolerant materials, such as the above mention elastomers, pneumatic or hydraulic filled structures. This support structure or mounting shaft could be made of the steel alloys currently employed in the construction of conventional gear types. Although, this mounting shaft could be constructed from a myriad of materials, such as, light weight aluminum alloys, plastics and even carbon composite to name a few.
All of the material and structural design choices for the individual Bearing Tooth could also be applied to the receiving pocket or support structure that receives the Bearing Tooth assembly pack. So for instance, a pneumatic tooth design could be mated with a solid rubber support ring within the gear housing, giving additional sound deadening and shock insolation performance. Or a solid steel Bearing Tooth, could have an pneumatic support ring in the gear housing/support structure. Also, the support structure design lends itself to the utilization of light weight materials, like those mentioned above. In addition many other low cost manufacturing methods can now be employed in the fabrication of the main support structure, such as, the injection molding, fabrication method, for plastic parts.
The final design point should be considered to obtain the full potential from the Bearing Tooth concept and that is, not to limit the support bearings to the interior of the individual Bearing Tooth or more precisely, the bearings should not be placed in the more restrictive envelope of the Bearing Tooth contact zone. The tooth geometry of the contact zone, is controlled by several factors, such as, the number of Bearing Teeth on the gear and pinion and the mounting radii, for the respective teeth, of the gear and pinion. Instead, the support bearings should be placed in the main gear housing or support structure and outside of the Bearing Tooth contact zone, by doing this the following advantages are allowed. Larger bearings can be utilized if they are mounted in the gear housing, outside of the more restrictive envelope, of the contact zone and these larger bearings can tolerate higher loads. Not having the need to include the support shaft, bearing sets and Bearing Tooth shell, within the same envelope, allows greater easy of accommodating the previously mentioned materials (eg. elastomers) and structure types (eg. pneumatic teeth). Lastly, if the support bearings are in the main gear housing, the Bearing Tooth itself, could be one complete, solid and uninterrupted shaft or structure. It is obvious that a solid 4 inch in diameter steel shaft with its mating bearing set within the main gear housing, will have a much greater load capacity than a Bearing Tooth, that must share this 4 inch in diameter envelope between a support shaft, bearing set and tooth shell.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a top view of a spoke type Bearing Tooth Gear set, with a 1 to 1 gear ratio.
FIG. 2 is a side view of the same spoke type Bearing Tooth Gear set shown in FIG. 1.
FIG. 3 is an exploded isometric view of a spoke type Bearing Tooth Gear with two Bearing Teeth and receiving pockets shown.
FIG. 4 is a top view of an on axis Bearing Tooth Gear set, with a 3 to 1 gear ratio.
FIG. 5 is a side view of the same on axis Bearing Tooth Gear shown in FIG. 4.
FIG. 6 is an exploded isometric view of an on axis Bearing Tooth Gear with one tooth attachment method shown.
FIG. 7 is an exploded isometric view of a spoke type Bearing Tooth Gear with five attachment methods shown.
FIG. 8 is an in plane gear set with the main gear employing Bearing Teeth and the pinion employing stationary teeth.
FIGS. 9A, 9B, and 9C shows 3 views of a quick release Bearing Tooth assembly.
FIG. 10 compares the tolerance envelopes of a Bearing Tooth and a conventional gear tooth.
FIG. 11 shows an elastomeric, fluid filled or gas filled, receiving pocket.
FIG. 12 shows a fluid filled or gas filled Bearing Tooth.
FIG. 13 is an exploded isometric view of an on axis Bearing Tooth Gear, employing the Bearing Teeth of FIG. 12 and the receiving pockets of FIG. 11.
DETAILED DESCRIPTION OF THE INVENTION
Several configurations that embody Bearing Tooth technology will be discussed in conjunction with a particular sketch but this does not necessarily limit those attributes to that configuration alone. Refer now to FIG. 1 & 2 which shows one of the preferred embodiments of the invention. The inventor has labeled assembly 70, as a spoke type, Bearing Tooth Gear set. Gear set 70 has a 1 to 1 gear ratio and is comprised of gear assembly 75 and pinion assembly 76. One of the more unique features of gear set 70 is the rotatable gear teeth 20 and 77, whose structural size can be larger than a conventional gear tooth and therefore are capable of handling higher loads, in addition tooth assemblies 20 and 77 can be quickly removed for servicing. Each of these tooth assemblies can be attached by a myriad methods to their respective support housings 71 and 72 and these gear housing are then supported by their respective torque transmission shafts 73 and 74 which can in turn, transmit rotative work to some other point. The geometry of support housings 71 and 72 are controlled by a number of factors such as the required design radii of these housings and the number and type of Bearing Teeth that these housings must receive. For example, the radial periphery of each gear housing must be designed so that this feature does not interfere with the mounting of its respective Bearing Tooth, such as the machine flat of feature 78, nor should a housing's radial periphery interfere with the meshing of teeth, from the mating gear. So some material could be removed to avoid this interference as in feature 79.
FIG. 3 shows item 75 which is an exploded view of one of the gear assemblies of gear set 70 shown in FIGS. 1 & 2. In this sketch, a more detailed view of Bearing Tooth assembly 20, gear housing 71 and a preferred attachment method, are shown. The attachment method shown utilizes screw type treads 11 on both the bearing housing 15 and a mating tread type 21 on the receiving pocket or socket 25 within the gear housing 71. Assume the Bearing Tooth contact structure 1 within the meshing or contact zone becomes damaged or worn, it would be a simple matter of mating a crescent wrench to the octagonal bolt head 8 or similar bolt head type and unscrew the Bearing Tooth assembly 20 from its receiving pocket 25. A new or reworked Bearing Tooth assembly could then be screwed into the receiving pocket 25 on the gear housing. If during the installation of Bearing Tooth assembly 20, some addition degree of depth control is required, shims 17 or 18 of varying thicknesses could be set between their corresponding mating surfaces between the Bearing Tooth assembly 20 and the gear housing 71, these follow. In the particular configuration shown, there are four potential shimable surfaces, shim 17 is designed to separate the three surfaces 22, 23, 24 of the housing 71 from their corresponding structures 12, 13, 14 on the bearing housing 15. Although, it should be recognized that shim 17 could be design to provide a separation space between any one set of surfaces (eg. 14 & 24). Shim 18 is much the same as a washer except for the ridge control of part thickness, shim 18 could also offer control, on the precise installation of the Bearing Tooth assembly 20, by providing separation between surfaces 16 and 78.
As can be seen in FIG. 3, the replacement of a damage gear tooth could be quite a simple and inexpensive process for a number of reasons. Consider the following, if an individual Bearing Tooth assembly 20 becomes damaged, it can be quickly replaced without removing the gear housing 71 from its torque transmission shaft 73. The repair of a large conventional gear is quite a different story. If a tooth is damaged or broken on a conventional gear, the whole gear must be removed from its transmission, which can be a very difficult task, as an example to remove a damaged 10 ft diameter gear from a large ship, one literally needs to cut a hole in the side of the hull. The whole gear must then be transported back to a gear manufacture for repair which could take weeks, this obviously is a very timely and costly process. The repair of a damage Bearing Tooth Gear would not suffer from the same lengthy repair times and high repair cost for the following reasons.
Part of the quick replacement time is not just the installation but the fact that a manufacture is much more likely to stock a relatively small, standard and possibly reworked or reconditioned Bearing Tooth assembly 20 because that Bearing Tooth assembly 20 would have a relatively low part cost and relatively high sales volume. So with a Bearing Tooth Gear set, it is much more likely that the parts used in its construction, will have the attribute of being "off the shelf", in fact, many of the parts that go into the construction of Bearing Tooth assembly 20 can be designed to utilize "off the shelf" supplier parts (eg. bearings, seals). With assembly 20 having the quality of being an "off the shelf" or a stock part, it is a simple matter to supply even the most distant customer with replacement parts in a very short period of time. With the world's current overnight express delivery services, a damaged Bearing Tooth Gear could be repaired within 24 hours or less, virtually world wide. So the damaged Bearing Tooth Gear would have shorter down times and therefore, the associated down time costs would be less. Also, the labor costs are less, when quickly replacing a damaged Bearing Tooth assembly 20 versus the time to dissemble a transmission to remove a conventional gear and the cost of parts for the standard Bearing Tooth assembly 20, will be much less than the cost of repairing a broken conventional gear tooth (eg. weld tooth on, re-machine fracture zone, heat treat gear, refinish tooth surface) or replacing the whole conventional gear.
FIG. 4 & 5 show an on axis Bearing Tooth Gear set 80 with a 3 to 1 gear ratio. Except for the 90 degree rotation of the axis for the individual Bearing Teeth assemblies 87, 90, the function is much the same as the spoke type Bearing Tooth Gear set 70, that being, pinion assembly 85 receives a torque from its torque transmission shaft 83, this load is then transmitted to gear assembly 86 through the rolling, meshing contact of tooth assemblies 87, 90, the gear housing 82 which is connected to torque transmission shaft 84, now conveys its imparted load to its aforementioned torque transmission shaft 84.
As with any gears using Bearing Tooth technology, the housings for both the gear 82 and the pinion 81 can be made from numerous material types, since the materials of the housings never come in contact with one another. Therefore, the toughen steel alloys required for the conventional gear tooth, to assure that the high bending, shear and contact loads can be sustained, are often employed for the rest of the gear structure (eg. housing) because often times the tooth track and housing are all one continuous part. Since the Bearing Tooth assemblies 87, 90 are separate parts from the gear housings 81, 82, the material selection for Bearing Tooth assemblies 87, 90 can be tailored to handle the high bending and contact loads. Therefore, more expensive materials can now be utilized, that would have the desired properties, yet these small assemblies 87, 90, would have little impact on the overall gear set 80 cost because of their relatively small size.
While the gear designer will want to assure that the gear housings 81, 82 will not be the "weak link", because like the conventional gear, the gear housings 81, 82 are not easily replaced, this does not mean that materials with lower tensile strengths (eg. aluminum alloys, plastics), than that of harden steel alloys, cannot be employed. Another point should be made here, that materials with high tensile strengths and low densities but poor contact load performance, such as, graphite epoxy composites, can also be used for the gear housings 81, 82. Because of the rolling action of the Bearing Tooth Gear's teeth and the increased material availability due to this rolling action, restriction on employing larger gear tooth sizes are eliminated. Unlike, the conventional gear, where tooth size drives the surface failure modes of wear, pitting and scoring, Bearing Teeth will not suffer from these same failure types (ie. sliding contact wear occurs much more rapidly than rolling contact wear). With larger tooth structures 87, 90 and their corresponding receiving structures, like the receiving pockets 25 of FIG. 3, loads can be dispersed over a larger material area and therefore the load per unit area will be less which allows the use of materials with lower tensile strengths.
FIG. 6 & 7 show exploded views of gear assemblies 85 and 75, which demonstrate a number of attachment methods to their respective housings 81 & 71. Referring first to FIG. 6, Gear assembly 85 depicts a Bearing Tooth Gear with rear access for the installation of Bearing Tooth assembly 90, through surface 152, this assembly could just as easily been installed on the forward face 150 of housing 81 or the radial periphery 151, the designer would need to tailor the installation method to his or her own needs. Depending on the use or more specifically the design of the machine, access to one of the three surfaces 150, 151, 152 mentioned may be easier than the other two, so the designer should choose the surface with the greatest accessibility, for Bearing Tooth assembly 90 installation.
Bearing Tooth assembly 90 could be supplied as a complete unit or the possibility of supplying component parts to this assembly exist, for instance, the contact or load bearing shaft 91 would be the most likely part to fail over the life of a gear. This load bearing shaft 91 could be a harden steel alloy to improve its wear life, also the contact shaft could be of varying lengths thereby effecting its engagement duration with the teeth of the mating gear (eg. tooth assembly 87). It can be seen that the cylindrical roller bearings 96 would contact load bearing shaft 91 and in turn would contact the bearing housing 95. When the load bearing shaft 91 is installed in the bearing housing 95 it must first be passed through the hole 92 in the bearing housing 95, the load bearing shaft 91 and roller bearings 96 could then be secured in the bearing housing 95 by installing the threaded 98 retaining cap 97 to the mating treads 99 in the bearing housing. This completed Bearing Tooth assembly 90 could then have the tip or the load bearing shaft 91 passed through the hole 88 in the forward face 150 of the gear housing 81. The Bearing Tooth assembly then can be secured by mating the threads 93 in the bearing housing 95 to the treads 153 in the gear housing 81, a crescent wrench or similar tool could be mated with the bolt head 94 to the required torque specifications. The gear assembly 85 can now be use to receive or transmit rotative energy down it torque transmission shaft 83. One should note that if the bearings 96 were not housed in the gear housing 81 but instead were contained in the load bearing shaft 91, the whole Bearing Tooth assembly 90 and therefore gear assembly 85 would not be able to sustain as great a loading, as the configuration depicted in FIG. 6.
The spoke type Bearing Tooth Gear 75 depicted in FIG. 7 shows five different attachment methods for five Bearing Tooth assemblies 20, 30, 40, 50, 60. All Bearing Tooth assemblies 20, 30, 40, 50 would have bearings sets contained in their perspective housing 15, 33, 43, 53, except for Bearing Tooth assembly 60 whose bearings 5 and seal 4 would mate directly with the gear housing 71 through a tailored side access receiving recess 63. Bearing Tooth assembly 60 would be retained in the side access receiving recess 63 by the installation of retaining cover 61 by passing fasteners 65 through the retaining cover holes 62 and then into the threaded holes 64 of the gear housing 71 and then applying the proper torque to the fasteners 65. As in FIG. 6 the load bearing shaft 1 could be of varying length to control the duration of tooth engagement with their mating teeth (FIG. 1 & 2 Bearing Tooth assembly 77). Several receiving recess or pockets 25, 38, 45, 54 are shown, these pockets can be threaded 21 or tapered 36 or straight sided 44 or utilize a side slip joint 55, these receiving pockets would interface with there corresponding Bearing Tooth assembly joint type, threaded 11, tapered 32, straight sided 42 or side slip joint 52. To secure Bearing Tooth assemblies 20, 30, 40, 50 would proceed as follows, Bearing Tooth assembly 20, could provide a check of the proper depth measurement, during a check installation. If a slight adjustment was required for the depth a shim 17 could be used to separate surfaces 22, 23, 24, from surfaces 12, 13, 14 or a shim 18 could be used to separate surface 78 from surface 16. A crescent wrench could then be applied to bolt head 8, to employ the proper torque to the Bearing Tooth assembly 20. Bearing Tooth assemblies 30 & 40 have equivalent attachment methods, each one of these assemblies 30 & 40 would be slipped into their corresponding receiving pockets 36, 44 until the holes 35 in the restrain flange 34 aligned with the holes 37 in the support housing, a bolt 56 or pin 57 could then be used to secure the Bearing Tooth assemblies 30 & 40 to the gear housing 71. Bearing Tooth assembly 50 would be slipped into its receiving pocket and a bolt 56 could then be installed to prevent Bearing Tooth assembly 50 from slipping free. Lastly, shoulders 31, 41, 51 on Bearing Tooth assemblies 30, 40, 50 could be used in conjunction with a shim 18, to obtain the proper separation from surface 78, or to remove any free play or "slop" from their respective Bearing Tooth assemblies 30, 40, 50.
The next sketch in the sequence is FIG. 8 and it depicts and in plane Bearing Tooth assembly 130 which employs a stationary tooth 135 pinion 134 which receives its rotative energy from its torque input shaft 136. The unique aspect of this configuration is the fact that the bearing assembly 146 is housed in the outer support housing ring 132 and not within the Bearing Tooth assemblies 148 contact zone 149, this allows for a larger diameter Bearing Tooth assembly 148 and therefore greater load carrying capability. In addition this larger envelope allows the other unique feature of employing more than one material type for the structure of the Bearing Tooth assembly 148. For instance a displacement and shock tolerant material such as an elastomeric material 147 could be bonded to high strength load carrying shaft 142, thereby giving a much quieter gear set (eg. lower decibel intensity and lower frequency or pitch), as a possible application, this quiet gear set could prove useful in the reduction of the noise signature of a nuclear sub.
The load carrying shaft 142 could then interface with the inner bearing race or ring 143, which in turn would contact the rolling elements 145, which contacts the outer race 144 and finally the bearing assembly 146 would be set or mounted in the receiving pockets 141. To retain the Bearing Tooth assembly 148 a threaded 139 retaining cap 138 could be set into the threaded 140 receiving pocket 141 and torqued into place by the use of the slot 137 and a screwdriver. In the last paragraph the option of employing an elastomeric material 147 in the construction of the Bearing Tooth assembly 148 was mentioned but the use of a sound deadening, shock absorbent material can be employed elsewhere on the Bearing Tooth Gear assembly 130, namely, the outer support housing ring 132 could also be constructed of elastomers or plastics, to name a few material choices. This outer support housing ring 132 could then be bonded or mechanically attached to the inner support housing 131, which in turn would be connected to torque transmission shaft 133. The advantages of employing shock absorbent material and structures 132, 147 can again be better understood with an example. Assume gear set 130 is part of a wench used on a construction crane, if that crane were to lift near it maximum rated load and that load were to shift and for a fraction of a second and the cable was not receiving the full load (eg. an I-beam slips down 1/3 of its length before again be restrained), a large shock load could be transmitted through the cable to the gear set but the Bearing Tooth Gear set 130 would have a greatly improve shock tolerance, over that of a conventional gear set, if it were to employ elastomeric structures 132, 147. With a conventional gear set structural failure of the pinion and gear teeth would likely result and if there were no other restrain mechanisms (eg. a winch brake), look out below.
Proceeding to FIGS. 9A, 9B and 9C, which shows three views of Bearing Tooth assembly 20 a cross-sectional, isometric and exploded cross-sectional. The following parts show a possible configuration for a Bearing Tooth assembly 20. Bearing Tooth contact structure 1 would be of such a geometry that it would mesh without binding but remain in contact with its mating gear tooth 77 through the entire tooth engagement. Bearing Tooth contact structure 1 could be of greater axial length if longer tooth engagement with mating gear teeth 77 is desired. Support bearing shaft 2 could be an uninterrupted part of, contact structure 1 but the support bearing shaft 2 and contact structure 1 could be made of different materials (eg. elastomers for contact structure 1 and hardened steel for support bearing shaft 2) to obtain different performance characteristics. Inner bearing race 7 would be bonded or mechanically attached to support bearing shaft 2, snap ring 3, seal 4 and top rolling elements 6 and top outer race 5 would need to be installed before the attachment of the inner bearing race 7. The bottom rolling elements 5 and bottom outer race can now be put in place, this collection of parts forms assembly 10, the bearing housing 15 can be slid over assembly 10 and then be secured by snapping snap ring 3 into the snap ring groove 9. The bearing housing 15 would be designed to receive assembly 10 with a close tolerance fit, its exterior circumference would be threaded 11 and be of the right diameter and thread type 11 to interface with its corresponding gear housing's 71 receiving pocket 25. Surfaces 12, 13, 14 and 16 would interface with shims 17 or 18 to maintain the proper separation between Bearing Tooth assembly 20 and the gear housing 71.
Building a close tolerance and relatively inexpensive part can be shown by referring to FIGS. 9A, 9B, 9C, & 10. In FIGS. 9A, 9B and 9C Bearing Tooth contact structure 1, support bearing shaft 2 and bearing housing 15 are relatively simple "turned" parts where very high tolerances can be obtained. Tolerance envelope 100 would be very small or "tight", for the Bearing Tooth contact structure 1, where tolerances of 10 thousands of an inch, can easily be obtained with such a part. FIG. 10 shows the placement of a Bearing Tooth assembly 20 in it corresponding receiving pocket 25. Accurate hole or receiving pocket 25 placement, is a much easier task to accomplish, than the milling or machining of a complex conventional gear tooth geometry 103 into the outer radius of a gear housing 82. Therefore, tolerance envelope 101 for the Bearing Tooth assembly 20 will be much tighter and easier to control than the conventional gear tooth tolerance envelope 102. With the comparatively less complex parts 1, 2, 15, 25 and the more simplistic manufacturing methods of the Bearing Tooth Gear assembly, tolerancing should be an easier parameter to control, so more accurate gears can be made at lower manufacturing costs. In addition, the rolling action of the Bearing Tooth assembly 20, allows the option of employ displacement and shock tolerant materials 147 (eg. elastomers) or structures 115, 125 (ie. FIG. 11, FIG. 12), which in turn relaxes tolerance requirements. As an example it is quite evident that a pneumatically filled Bearing Tooth 125 can withstand placement and the corresponding engagement inaccuracies better that a ridge, metallic conventional gear tooth 103, whose material strength requirements have created a hard and brittle structure, which has little tolerance to the cyclical shock loading, that would be created by inaccurate tooth geometry, placement or orientation.
Lastly, FIGS. 11, 12 & 13 demonstrate a Bearing Tooth technology which employs addition methods, for withstanding displacement inaccuracies and high shock loads. FIG. 11 shows a receiving pocket assembly 115, which would be made from displacement and shock tolerant materials 116 (eg. elastomers) and could also employ pneumatically or hydraulically filled cavities 120 which could offer varying shock attenuation and sound abatement performance. The receiving pocket assembly 115 would have a internal ridge receiving pocket 118 which would bond or be mechanically attached to the displacement and shock tolerant material 116 and have a restrain mechanism, such as, being threaded 117 and having internal surface 119 to counter and moment loading.
In FIG. 12 the pneumatically or hydraulically filled Bearing Tooth assembly 125 would have the pneumatic or hydraulic fill 128, filling retaining envelope 127 and this retaining envelope 127 would be mounted on a support shaft 126. The support shaft 126 would then interface with the inner bearing race 7, which would interface with rolling element 6 which would interface with outer race 5. The bearing components 5, 6, 7 and the lower portion of support shaft 126 would be housed in the bearing housing 15 as would the seal 4, these components would then be restrained by a snap ring 3, which would be snapped into the snap ring groove 9. The threaded structure 11 of bearing housing 15 would be design to mate with the threads 117 of internal ridge receiving pocket 118, in addition surfaces 12, 13, 14, 19 of bearing housing 15 would closely interface with surface 119 of the receiving pocket. The octagonal bolt head 8 would be used to secure the pneumatically or hydraulically filled Bearing Tooth assembly 125.
FIG. 13 shows an isometric of gear assembly 110 which employs pneumatically or hydraulically filled Bearing Tooth assemblies 125 and receiving pocket assemblies 115. The gear housing 111 is bonded or mechanically attached to the displacement and shock tolerant material 116 which is bonded or mechanically attached to internal ridge receiving pocket 118. The pneumatically or hydraulically filled Bearing Tooth assembly 125 would be secured by mating its treads 11 to the threads 117 of the internal ridge receiving pocket 118, the surfaces 13, 19 on the bearing housing 15 would contact the internal surface 119 of the internal ridge receiving pocket 118, the Bearing Tooth assembly 125 would then be tighten to the proper torque specifications, by mating a crescent wrench or like tool to octagonal bolt head 8 on bearing housing 15. Once all of the pneumatically or hydraulically filled Bearing Tooth assemblies 125 are installed, loads could then be applied to the retaining envelope 127, with its pneumatic or hydraulic fill 128 and then to the support shaft 126.
The foregoing description of the preferred embodiments of the invention was given for illustrative purposes. These embodiments were not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications, variations and combinations of the above disclosures are possible. It is intended that the scope of the invention not be limited by the detailed description, but rather by the following claims. | Elaboration on the merits of an improved gear family known as Bearing Tooth Gears. The rotative contact of meshing Bearing Teeth in a Bearing Tooth Gear set, allows for an increase in candidate materials, used in the construction of these gears and allows for improved structural designs of the Bearing Tooth assemblies and gear housings. In addition, prefer positioning of support bearings is also conveyed. | Briefly describe the main idea outlined in the provided context. | [
"REFERENCES TO RELATED APPLICATIONS This application is a continuation in part for the application with Ser.",
"No. 08/075,147, which was filed on Jun. 10, 1993 now U.S. Pat. No. 5,381,704.",
"The earlier filing date of this application is hereby claimed.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention This invention relates to the Bearing Tooth Gear and related gear types, with rotatable gear teeth and in particular the attachment methods, bearing placement, constructive materials and specific design types and configurations of said tooth structures.",
"Description of Prior Art The design and manufacture of conventional gears, is an old and a somewhat antiquated technology or more accurately, an art.",
"The world's gear manufactures still use the same designs, construction methods and materials, that have changed little for the past century, in particular, cantilever tooth structures, which can be of a complex nature or geometry, such as, the Spiral Bevel, Helical, Crossed Helical, Hypoid, Spiroid, Helicon are machined into metallic alloys and then hardened by various heat treating processes.",
"These teeth are designed to be in sliding contact, with a thin lubricant film separating the mating teeth.",
"There are numerous advantages to be had by replacing the sliding contact, of the conventional gear, with the rolling contact, of the Bearing Tooth Gear.",
"The obvious energy savings due to the difference in sliding versus rolling friction, is just the start.",
"Some of the improvements of the Bearing Tooth Gear, follow.",
"Field servicing is now an option, servicing is less costly, increases the number of candidate manufacturing materials, lighter weight structures can be made, increases the number of manufacturing processes that can be utilized, tighter tolerances easier to maintain on tooth geometry and tooth placement, stocking of standard tooth types is cost effective, decreases overall cost in manufacturing, quicker build and delivery times of replacement parts, enlarges operating envelope, reduces operating noise, reduces lubricant fluid drag, greater tolerance to shock loads, more tolerant of foreign object contamination, smaller and more highly loaded gear sets can be made.",
"Rotatable gear teeth have been presented in past patents, such as, Stanley (U.S. Pat. No. 277,802;",
"issued May 15, 1883): Saladee (U.S. Pat. No. 486,055;",
"issued Nov. 8, 1892): Jamieson (U.S. Pat. No. 596,884;",
"issued Jan. 4, 1898): Jamieson (U.S. Pat. No. 613,148;",
"issued Oct. 25, 1898): Jamieson (U.S. Pat. No. 620,074;",
"issued Feb. 21, 1899): McCormick (U.S. Pat. No. 633,470;",
"issued Sep. 19, 1899): Froelich (U.S. Pat. No. 1,159,486;",
"issued Nov., 9, 1915): Wojtowicz (U.S. Pat. No. 2,792,715;",
"issued May 21, 1957): Gilbert (U.S. Pat. No. 3,608,392;",
"issued Jun. 15, 1970);",
"Grayson (U.S. Pat. No. 3,845,670;",
"issued Nov. 5, 1974): Knutson (U.S. Pat. No. 4,093,036;",
"issued Jun. 6, 1978): Fujita (U.S. Pat. No. 4,541,297;",
"issued Sep. 17, 1985): and Kerkhoff (U.S. Pat. No. 4,879,920;",
"issued Nov. 14, 1989).",
"While some of the above mentioned patents touch on attributes such as the ability to replace worn parts (U.S. Pat. Nos. 277,802;",
"596,884;",
"1,159,486;",
"2,792,715) diminishing friction and wear (U.S. Pat. Nos. 486,055;",
"596,884;",
"613,148;",
"633,470;",
"4,879,920) silent operation (U.S. Pat. Nos. 1,159,486;",
"3,608,392) backlash elimination (U.S. Pat. Nos. 3,608,392;",
"4,879,920), none of these patents explore the fully potential of the technology nor the means to obtain that potential.",
"Items such as, the option to exercise tight, yet more cost effective, tolerance control during manufacture yet being more adaptive to manufacturing inaccuracies, or the fact that fewer and larger, more load capable, gear teeth can be employed.",
"Or the option of being able to have quick release Bearing Tooth packs or assemblies, which allow teeth to be replaced with greater ease.",
"Or the option of employing displacement and shock tolerant materials and structures such as elastomeric and/or plastics and/or fluid filled and/or gas filled teeth and/or similar materials and/or structures for the zone that receives the bearing packs, within the support housings and the option of using cheaper and/or light weight load bearing materials for these structures, all lead to the following attributes;",
"gear sets that are tolerant of higher shock loads, much quieter gear sets due to greater sound adsorption and vibrational dampening capabilities, elimination of high stress point loading, less massive structures for weight critical applications (eg.",
"aerospace systems), greater capability to tolerate adverse operating environments, such as high dirt, high grit, high moisture and even corrosive environments.",
"And finally, by not limiting the support bearings to the interior of the rotatable tooth, gives the option of constructing a Bearing Tooth, which possesses greater structural continuity and greater beam cross-section, thereby giving greater bending and torsional load capacity.",
"SUMMARY OF THE INVENTION To elaborate upon the previously mentioned objects, all of the benefits or attributes of this invention are a result of the following change of mind set, that being, the substitution of rolling contact for sliding contact, the latter of which, is present in all conventional gear sets.",
"The rolling contact of the Bearing Tooth Gear allows a number of capabilities to be added to its list of attributes.",
"Capabilities which at best, are difficult to achieve if not impossible with conventional gear sets, where sliding contact is the method of tooth engagement.",
"The rolling contact of the Bearing Tooth gear will improve the energy efficiency of a machine's gear train because of several factors.",
"The obvious fact that rolling friction is less than sliding friction, even if the sliding surfaces are lubricated, can be verified, by checking just about any lubrication handbook but there are other ways that conventional gear efficiency is affected.",
"One lose factor that is often ignored is the drag produced by the fluid lubricant, which is required for the conventional gear set.",
"It is often thought that this drag effect is of little consequence even when employing heavy weight or high viscosity lubricants.",
"Normally this is the case but have a machine operate in a low temperature environment and the viscous drag effect, can become substantial.",
"Consider the example of a cold winter day in the Midwest, where perhaps the temperature drops to -10 degrees Fahrenheit.",
"It is not difficult to envision what happens to the oil, in the differential of ones car, it turns to a virtual glue and this thicken lubricant will substantial impede the rotation of the gear set.",
"Now consider the fact that perhaps 30 million commuters are in this low temperature region and are experiencing this lubricant drag effect, the cumulative energy loses would be huge and this scenario happens more than once a year.",
"The Bearing Tooth Gear differs, in that, a Bearing Tooth Gear set, need not be immersed in a lubricant because of the rolling action and materials and structures that the Bearing Tooth can employ.",
"The only location where lubrication is required for a Bearing Tooth assembly is within the support bearings of the individual tooth and when one considers quantity of lubricant and size of the structures, the fluid drag would truly be of little consequence.",
"While some conventional gear designers have attempted to employ some measure of field servicing, by having removable tooth tracks of perhaps 8 to 10 gear teeth, there are problems with obtaining adequate tolerances with this method.",
"If a facility undertakes the machining of a 10 tooth gear track, with its complex geometry, it soon finds the difficult in holding tight tolerance control on such a intricate and complex part.",
"This problem expands, when for example, 8 of these tracks must be mated with a support housing.",
"Now a reasonable degree of tolerance control must be exercised with the positional locating and with the three axis orientation, of these parts, relative to the gear housing.",
"To have a conventional gear set with high speed capability and high transmission efficiency, requires tight tolerance control.",
"A general manufacturing rule is, the tighter the tolerance control, the higher the price of manufacture.",
"In contrast, the Bearing Tooth Gear has a simpler geometry, with cylindrical and cylindrical like (eg.",
"bell shaped), cross sections which allow the very high tolerance control of a turned part.",
"Also, the accurate locating of the individual Bearing Tooth, in the support housing, is an easier task for several reasons.",
"One of the more obvious reasons is, the three axis angular alignment requirement, of the conventional gear tooth, is reduced to, two axis, with the Bearing Tooth Gear.",
"There is no clocking tolerance or control requirement for the third axis, or the axis of rotation, for the individual Bearing Tooth.",
"Since the third axis is the axis a Bearing Tooth spins on and is not a set feature, as with a conventional gear, there is no need to exercise tolerance control on this parameter.",
"Also, the relatively simplistic structure of a receptacle hole, for an individual Bearing Tooth assemble, is a feature where high tolerances are much easier to obtain versus the machining of a conventional gear tooth, with its complex geometry and its stringent placement and orientation requirements.",
"Lastly, even though a more accurate structure can be obtained with the Bearing Tooth Gear, it does not require the same stringent tolerance control of the conventional gear.",
"Because of the options available to the Bearing Tooth Gear, such as the use of displacement tolerant materials (e.g. elastomers), the Bearing Tooth Gear can accommodate greater manufacturing inaccuracies.",
"Another point to consider is that most of the conventional gear's failure modes are inapplicable to the Bearing Gear (eg.",
"pitting, scoring) and some are greatly reduced (eg.",
"wear).",
"Thus these failure types which for the conventional gear, are driven by large tooth size, do not limit the tooth size of the Bearing Gear.",
"This gives the option of employing larger gear teeth with higher individual tooth load capacity, which in turn allows the use of smaller more compact gear housings which are capable of transmitting the same torque loads as a conventional gear with its large diameter and low tooth loads (eg.",
"Torque=Tooth Load×Housing Radius).",
"Not only can the tooth structure be larger for the Bearing Tooth Gear but fewer teeth are required to cover a given circumference, thus there are fewer structures to manufacture and therefore fewer structures to exercise tolerance control on.",
"All of these features reduce cost and add to the practicality of having replaceable gear teeth which in turn greatly reduces any future repair costs.",
"With some of these roadblocks and obstructions removed from the premise of replaceable gear teeth, further refinements can still be made, in the methods with which these Bearing Teeth are attached, to the main gear housing.",
"To simplify the repair and replacement of damage or worn Bearing Teeth, complete Bearing Tooth packs or assemblies could be made, which contain a load and environment capable bearing set, of the designers choice.",
"This could include one or a combination of the following bearing types;",
"ball bearings single or multi-row, angular-contact ball bearings, ball bushings, roller bearings, cylindrical roller bearings, needle bearings, tapered roller bearings, spherical roller bearings, fluid film bearings, journal bearings and finally thrust bearings of the ball, straight-roller or tapered-roller type, could be used in conjunction with any of the above radial load type bearings.",
"The proper bearing type or types could be selected to accommodate all projected operating speeds and all projected axial, bending, shear and torsional loads.",
"These tooth packs would have seals to contain all internal lubricants and assure complete environmental insolation.",
"These packs could then have a myriad of attachment methods to the gear housing, external threading, tapered slip joint, straight slip joint, pin or bolt restraints, side slip joint, side access ports.",
"With these totally self contained Bearing Tooth assemblies not only would the act of repair and servicing be greatly simplified but the individual part cost will decrease due to the mass production aspect, of families of varying Bearing Tooth types.",
"This mass production aspect can apply to smaller conventional gears, where perhaps 1,000 one inch in diameter spur gears are manufactured but this option soon becomes less practical as the gear size increases and the number of applications decrease.",
"For instance, if a manufacture has an order for 3 ten foot in diameter conventional gear types, that manufacture will not build any spares because it maybe ten years before another gear of this type is purchased, if ever.",
"If the same order was place for 3 Bearing Tooth Gears, with 30 teeth per gear, it could be cost effective to build 100 or 150 teeth, where the spares could be utilized for future orders of different gear types, that could utilized this standard tooth type (eg.",
"perhaps a 5 foot in diameter gear could use the Bearing Teeth from this tooth family).",
"The rolling contact aspect, of the Bearing Tooth Gear, again comes into play with this next manufacturing option and that is, an increase in the list of candidate materials and in the design choices for the tooth and housing types, that the designer can now employ.",
"The conventional gear designers are limited in types of materials and processes they can utilize, because of the contact zone environment, with its high contact and shear loading and the high bending stresses experienced by these relatively, small highly loaded cantilever beams.",
"These operating characteristics of the conventional gear, will cause all but a few materials to fail.",
"So except for the occasional Nylon or Brass gears with their low load and operational speed limits, the material of choice is a harden steel alloy.",
"The steel alloys used in the construction of most gear types are heavy, brittle, difficult to machine and both costly as a material and costly to process.",
"A comparison to systems that use rolling structures of varying materials and configurations, could prove useful here.",
"So as an example the automobile, with its elastomeric, pneumatically filled structures that interface with the road surface (eg.",
"tires), which among other functions, contributes to the shock dispersion or diffusion capability of the suspension system, an elastomeric, pneumatically filled Bearing Tooth could provide the same capability to a gear set.",
"Again, the design of an individual Bearing Tooth can be much like an automobile tire, where there are various design choices available for the tread and the ply designs (eg.",
"radial), which among other functions, control wear patterns and modulating or decreasing the operational noise signature of a gear set.",
"Like the tire designer, the gear designer can choose various rubber compounds that offer varying rolling friction (eg.",
"traction) and wear performance.",
"Bearing Teeth could be designed to handle high loads with minimal deflection or displacement at the contact point.",
"By following the tire model once again, the technology of the solid rubber tire of the industrial forklift or the high pressure tire of the Navy's, carrier based, aircraft, could be employed in the design of Bearing Teeth that require high load, minimal displacement, operating characteristics.",
"And some applications may require the high pressure pneumatic performance but a high pressure hydraulically filled Bearing Tooth could provide similar performance, yet offer a more benign failure behavior.",
"Finally, each Bearing Tooth would have a support structure that interfaces with the shock load tolerant materials, such as the above mention elastomers, pneumatic or hydraulic filled structures.",
"This support structure or mounting shaft could be made of the steel alloys currently employed in the construction of conventional gear types.",
"Although, this mounting shaft could be constructed from a myriad of materials, such as, light weight aluminum alloys, plastics and even carbon composite to name a few.",
"All of the material and structural design choices for the individual Bearing Tooth could also be applied to the receiving pocket or support structure that receives the Bearing Tooth assembly pack.",
"So for instance, a pneumatic tooth design could be mated with a solid rubber support ring within the gear housing, giving additional sound deadening and shock insolation performance.",
"Or a solid steel Bearing Tooth, could have an pneumatic support ring in the gear housing/support structure.",
"Also, the support structure design lends itself to the utilization of light weight materials, like those mentioned above.",
"In addition many other low cost manufacturing methods can now be employed in the fabrication of the main support structure, such as, the injection molding, fabrication method, for plastic parts.",
"The final design point should be considered to obtain the full potential from the Bearing Tooth concept and that is, not to limit the support bearings to the interior of the individual Bearing Tooth or more precisely, the bearings should not be placed in the more restrictive envelope of the Bearing Tooth contact zone.",
"The tooth geometry of the contact zone, is controlled by several factors, such as, the number of Bearing Teeth on the gear and pinion and the mounting radii, for the respective teeth, of the gear and pinion.",
"Instead, the support bearings should be placed in the main gear housing or support structure and outside of the Bearing Tooth contact zone, by doing this the following advantages are allowed.",
"Larger bearings can be utilized if they are mounted in the gear housing, outside of the more restrictive envelope, of the contact zone and these larger bearings can tolerate higher loads.",
"Not having the need to include the support shaft, bearing sets and Bearing Tooth shell, within the same envelope, allows greater easy of accommodating the previously mentioned materials (eg.",
"elastomers) and structure types (eg.",
"pneumatic teeth).",
"Lastly, if the support bearings are in the main gear housing, the Bearing Tooth itself, could be one complete, solid and uninterrupted shaft or structure.",
"It is obvious that a solid 4 inch in diameter steel shaft with its mating bearing set within the main gear housing, will have a much greater load capacity than a Bearing Tooth, that must share this 4 inch in diameter envelope between a support shaft, bearing set and tooth shell.",
"BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a top view of a spoke type Bearing Tooth Gear set, with a 1 to 1 gear ratio.",
"FIG. 2 is a side view of the same spoke type Bearing Tooth Gear set shown in FIG. 1. FIG. 3 is an exploded isometric view of a spoke type Bearing Tooth Gear with two Bearing Teeth and receiving pockets shown.",
"FIG. 4 is a top view of an on axis Bearing Tooth Gear set, with a 3 to 1 gear ratio.",
"FIG. 5 is a side view of the same on axis Bearing Tooth Gear shown in FIG. 4. FIG. 6 is an exploded isometric view of an on axis Bearing Tooth Gear with one tooth attachment method shown.",
"FIG. 7 is an exploded isometric view of a spoke type Bearing Tooth Gear with five attachment methods shown.",
"FIG. 8 is an in plane gear set with the main gear employing Bearing Teeth and the pinion employing stationary teeth.",
"FIGS. 9A, 9B, and 9C shows 3 views of a quick release Bearing Tooth assembly.",
"FIG. 10 compares the tolerance envelopes of a Bearing Tooth and a conventional gear tooth.",
"FIG. 11 shows an elastomeric, fluid filled or gas filled, receiving pocket.",
"FIG. 12 shows a fluid filled or gas filled Bearing Tooth.",
"FIG. 13 is an exploded isometric view of an on axis Bearing Tooth Gear, employing the Bearing Teeth of FIG. 12 and the receiving pockets of FIG. 11.",
"DETAILED DESCRIPTION OF THE INVENTION Several configurations that embody Bearing Tooth technology will be discussed in conjunction with a particular sketch but this does not necessarily limit those attributes to that configuration alone.",
"Refer now to FIG. 1 &",
"2 which shows one of the preferred embodiments of the invention.",
"The inventor has labeled assembly 70, as a spoke type, Bearing Tooth Gear set.",
"Gear set 70 has a 1 to 1 gear ratio and is comprised of gear assembly 75 and pinion assembly 76.",
"One of the more unique features of gear set 70 is the rotatable gear teeth 20 and 77, whose structural size can be larger than a conventional gear tooth and therefore are capable of handling higher loads, in addition tooth assemblies 20 and 77 can be quickly removed for servicing.",
"Each of these tooth assemblies can be attached by a myriad methods to their respective support housings 71 and 72 and these gear housing are then supported by their respective torque transmission shafts 73 and 74 which can in turn, transmit rotative work to some other point.",
"The geometry of support housings 71 and 72 are controlled by a number of factors such as the required design radii of these housings and the number and type of Bearing Teeth that these housings must receive.",
"For example, the radial periphery of each gear housing must be designed so that this feature does not interfere with the mounting of its respective Bearing Tooth, such as the machine flat of feature 78, nor should a housing's radial periphery interfere with the meshing of teeth, from the mating gear.",
"So some material could be removed to avoid this interference as in feature 79.",
"FIG. 3 shows item 75 which is an exploded view of one of the gear assemblies of gear set 70 shown in FIGS. 1 &",
"In this sketch, a more detailed view of Bearing Tooth assembly 20, gear housing 71 and a preferred attachment method, are shown.",
"The attachment method shown utilizes screw type treads 11 on both the bearing housing 15 and a mating tread type 21 on the receiving pocket or socket 25 within the gear housing 71.",
"Assume the Bearing Tooth contact structure 1 within the meshing or contact zone becomes damaged or worn, it would be a simple matter of mating a crescent wrench to the octagonal bolt head 8 or similar bolt head type and unscrew the Bearing Tooth assembly 20 from its receiving pocket 25.",
"A new or reworked Bearing Tooth assembly could then be screwed into the receiving pocket 25 on the gear housing.",
"If during the installation of Bearing Tooth assembly 20, some addition degree of depth control is required, shims 17 or 18 of varying thicknesses could be set between their corresponding mating surfaces between the Bearing Tooth assembly 20 and the gear housing 71, these follow.",
"In the particular configuration shown, there are four potential shimable surfaces, shim 17 is designed to separate the three surfaces 22, 23, 24 of the housing 71 from their corresponding structures 12, 13, 14 on the bearing housing 15.",
"Although, it should be recognized that shim 17 could be design to provide a separation space between any one set of surfaces (eg.",
"14 &",
"24).",
"Shim 18 is much the same as a washer except for the ridge control of part thickness, shim 18 could also offer control, on the precise installation of the Bearing Tooth assembly 20, by providing separation between surfaces 16 and 78.",
"As can be seen in FIG. 3, the replacement of a damage gear tooth could be quite a simple and inexpensive process for a number of reasons.",
"Consider the following, if an individual Bearing Tooth assembly 20 becomes damaged, it can be quickly replaced without removing the gear housing 71 from its torque transmission shaft 73.",
"The repair of a large conventional gear is quite a different story.",
"If a tooth is damaged or broken on a conventional gear, the whole gear must be removed from its transmission, which can be a very difficult task, as an example to remove a damaged 10 ft diameter gear from a large ship, one literally needs to cut a hole in the side of the hull.",
"The whole gear must then be transported back to a gear manufacture for repair which could take weeks, this obviously is a very timely and costly process.",
"The repair of a damage Bearing Tooth Gear would not suffer from the same lengthy repair times and high repair cost for the following reasons.",
"Part of the quick replacement time is not just the installation but the fact that a manufacture is much more likely to stock a relatively small, standard and possibly reworked or reconditioned Bearing Tooth assembly 20 because that Bearing Tooth assembly 20 would have a relatively low part cost and relatively high sales volume.",
"So with a Bearing Tooth Gear set, it is much more likely that the parts used in its construction, will have the attribute of being "off the shelf", in fact, many of the parts that go into the construction of Bearing Tooth assembly 20 can be designed to utilize "off the shelf"",
"supplier parts (eg.",
"bearings, seals).",
"With assembly 20 having the quality of being an "off the shelf"",
"or a stock part, it is a simple matter to supply even the most distant customer with replacement parts in a very short period of time.",
"With the world's current overnight express delivery services, a damaged Bearing Tooth Gear could be repaired within 24 hours or less, virtually world wide.",
"So the damaged Bearing Tooth Gear would have shorter down times and therefore, the associated down time costs would be less.",
"Also, the labor costs are less, when quickly replacing a damaged Bearing Tooth assembly 20 versus the time to dissemble a transmission to remove a conventional gear and the cost of parts for the standard Bearing Tooth assembly 20, will be much less than the cost of repairing a broken conventional gear tooth (eg.",
"weld tooth on, re-machine fracture zone, heat treat gear, refinish tooth surface) or replacing the whole conventional gear.",
"FIG. 4 &",
"5 show an on axis Bearing Tooth Gear set 80 with a 3 to 1 gear ratio.",
"Except for the 90 degree rotation of the axis for the individual Bearing Teeth assemblies 87, 90, the function is much the same as the spoke type Bearing Tooth Gear set 70, that being, pinion assembly 85 receives a torque from its torque transmission shaft 83, this load is then transmitted to gear assembly 86 through the rolling, meshing contact of tooth assemblies 87, 90, the gear housing 82 which is connected to torque transmission shaft 84, now conveys its imparted load to its aforementioned torque transmission shaft 84.",
"As with any gears using Bearing Tooth technology, the housings for both the gear 82 and the pinion 81 can be made from numerous material types, since the materials of the housings never come in contact with one another.",
"Therefore, the toughen steel alloys required for the conventional gear tooth, to assure that the high bending, shear and contact loads can be sustained, are often employed for the rest of the gear structure (eg.",
"housing) because often times the tooth track and housing are all one continuous part.",
"Since the Bearing Tooth assemblies 87, 90 are separate parts from the gear housings 81, 82, the material selection for Bearing Tooth assemblies 87, 90 can be tailored to handle the high bending and contact loads.",
"Therefore, more expensive materials can now be utilized, that would have the desired properties, yet these small assemblies 87, 90, would have little impact on the overall gear set 80 cost because of their relatively small size.",
"While the gear designer will want to assure that the gear housings 81, 82 will not be the "weak link", because like the conventional gear, the gear housings 81, 82 are not easily replaced, this does not mean that materials with lower tensile strengths (eg.",
"aluminum alloys, plastics), than that of harden steel alloys, cannot be employed.",
"Another point should be made here, that materials with high tensile strengths and low densities but poor contact load performance, such as, graphite epoxy composites, can also be used for the gear housings 81, 82.",
"Because of the rolling action of the Bearing Tooth Gear's teeth and the increased material availability due to this rolling action, restriction on employing larger gear tooth sizes are eliminated.",
"Unlike, the conventional gear, where tooth size drives the surface failure modes of wear, pitting and scoring, Bearing Teeth will not suffer from these same failure types (ie.",
"sliding contact wear occurs much more rapidly than rolling contact wear).",
"With larger tooth structures 87, 90 and their corresponding receiving structures, like the receiving pockets 25 of FIG. 3, loads can be dispersed over a larger material area and therefore the load per unit area will be less which allows the use of materials with lower tensile strengths.",
"FIG. 6 &",
"7 show exploded views of gear assemblies 85 and 75, which demonstrate a number of attachment methods to their respective housings 81 &",
"71.",
"Referring first to FIG. 6, Gear assembly 85 depicts a Bearing Tooth Gear with rear access for the installation of Bearing Tooth assembly 90, through surface 152, this assembly could just as easily been installed on the forward face 150 of housing 81 or the radial periphery 151, the designer would need to tailor the installation method to his or her own needs.",
"Depending on the use or more specifically the design of the machine, access to one of the three surfaces 150, 151, 152 mentioned may be easier than the other two, so the designer should choose the surface with the greatest accessibility, for Bearing Tooth assembly 90 installation.",
"Bearing Tooth assembly 90 could be supplied as a complete unit or the possibility of supplying component parts to this assembly exist, for instance, the contact or load bearing shaft 91 would be the most likely part to fail over the life of a gear.",
"This load bearing shaft 91 could be a harden steel alloy to improve its wear life, also the contact shaft could be of varying lengths thereby effecting its engagement duration with the teeth of the mating gear (eg.",
"tooth assembly 87).",
"It can be seen that the cylindrical roller bearings 96 would contact load bearing shaft 91 and in turn would contact the bearing housing 95.",
"When the load bearing shaft 91 is installed in the bearing housing 95 it must first be passed through the hole 92 in the bearing housing 95, the load bearing shaft 91 and roller bearings 96 could then be secured in the bearing housing 95 by installing the threaded 98 retaining cap 97 to the mating treads 99 in the bearing housing.",
"This completed Bearing Tooth assembly 90 could then have the tip or the load bearing shaft 91 passed through the hole 88 in the forward face 150 of the gear housing 81.",
"The Bearing Tooth assembly then can be secured by mating the threads 93 in the bearing housing 95 to the treads 153 in the gear housing 81, a crescent wrench or similar tool could be mated with the bolt head 94 to the required torque specifications.",
"The gear assembly 85 can now be use to receive or transmit rotative energy down it torque transmission shaft 83.",
"One should note that if the bearings 96 were not housed in the gear housing 81 but instead were contained in the load bearing shaft 91, the whole Bearing Tooth assembly 90 and therefore gear assembly 85 would not be able to sustain as great a loading, as the configuration depicted in FIG. 6. The spoke type Bearing Tooth Gear 75 depicted in FIG. 7 shows five different attachment methods for five Bearing Tooth assemblies 20, 30, 40, 50, 60.",
"All Bearing Tooth assemblies 20, 30, 40, 50 would have bearings sets contained in their perspective housing 15, 33, 43, 53, except for Bearing Tooth assembly 60 whose bearings 5 and seal 4 would mate directly with the gear housing 71 through a tailored side access receiving recess 63.",
"Bearing Tooth assembly 60 would be retained in the side access receiving recess 63 by the installation of retaining cover 61 by passing fasteners 65 through the retaining cover holes 62 and then into the threaded holes 64 of the gear housing 71 and then applying the proper torque to the fasteners 65.",
"As in FIG. 6 the load bearing shaft 1 could be of varying length to control the duration of tooth engagement with their mating teeth (FIG.",
"1 &",
"2 Bearing Tooth assembly 77).",
"Several receiving recess or pockets 25, 38, 45, 54 are shown, these pockets can be threaded 21 or tapered 36 or straight sided 44 or utilize a side slip joint 55, these receiving pockets would interface with there corresponding Bearing Tooth assembly joint type, threaded 11, tapered 32, straight sided 42 or side slip joint 52.",
"To secure Bearing Tooth assemblies 20, 30, 40, 50 would proceed as follows, Bearing Tooth assembly 20, could provide a check of the proper depth measurement, during a check installation.",
"If a slight adjustment was required for the depth a shim 17 could be used to separate surfaces 22, 23, 24, from surfaces 12, 13, 14 or a shim 18 could be used to separate surface 78 from surface 16.",
"A crescent wrench could then be applied to bolt head 8, to employ the proper torque to the Bearing Tooth assembly 20.",
"Bearing Tooth assemblies 30 &",
"40 have equivalent attachment methods, each one of these assemblies 30 &",
"40 would be slipped into their corresponding receiving pockets 36, 44 until the holes 35 in the restrain flange 34 aligned with the holes 37 in the support housing, a bolt 56 or pin 57 could then be used to secure the Bearing Tooth assemblies 30 &",
"40 to the gear housing 71.",
"Bearing Tooth assembly 50 would be slipped into its receiving pocket and a bolt 56 could then be installed to prevent Bearing Tooth assembly 50 from slipping free.",
"Lastly, shoulders 31, 41, 51 on Bearing Tooth assemblies 30, 40, 50 could be used in conjunction with a shim 18, to obtain the proper separation from surface 78, or to remove any free play or "slop"",
"from their respective Bearing Tooth assemblies 30, 40, 50.",
"The next sketch in the sequence is FIG. 8 and it depicts and in plane Bearing Tooth assembly 130 which employs a stationary tooth 135 pinion 134 which receives its rotative energy from its torque input shaft 136.",
"The unique aspect of this configuration is the fact that the bearing assembly 146 is housed in the outer support housing ring 132 and not within the Bearing Tooth assemblies 148 contact zone 149, this allows for a larger diameter Bearing Tooth assembly 148 and therefore greater load carrying capability.",
"In addition this larger envelope allows the other unique feature of employing more than one material type for the structure of the Bearing Tooth assembly 148.",
"For instance a displacement and shock tolerant material such as an elastomeric material 147 could be bonded to high strength load carrying shaft 142, thereby giving a much quieter gear set (eg.",
"lower decibel intensity and lower frequency or pitch), as a possible application, this quiet gear set could prove useful in the reduction of the noise signature of a nuclear sub.",
"The load carrying shaft 142 could then interface with the inner bearing race or ring 143, which in turn would contact the rolling elements 145, which contacts the outer race 144 and finally the bearing assembly 146 would be set or mounted in the receiving pockets 141.",
"To retain the Bearing Tooth assembly 148 a threaded 139 retaining cap 138 could be set into the threaded 140 receiving pocket 141 and torqued into place by the use of the slot 137 and a screwdriver.",
"In the last paragraph the option of employing an elastomeric material 147 in the construction of the Bearing Tooth assembly 148 was mentioned but the use of a sound deadening, shock absorbent material can be employed elsewhere on the Bearing Tooth Gear assembly 130, namely, the outer support housing ring 132 could also be constructed of elastomers or plastics, to name a few material choices.",
"This outer support housing ring 132 could then be bonded or mechanically attached to the inner support housing 131, which in turn would be connected to torque transmission shaft 133.",
"The advantages of employing shock absorbent material and structures 132, 147 can again be better understood with an example.",
"Assume gear set 130 is part of a wench used on a construction crane, if that crane were to lift near it maximum rated load and that load were to shift and for a fraction of a second and the cable was not receiving the full load (eg.",
"an I-beam slips down 1/3 of its length before again be restrained), a large shock load could be transmitted through the cable to the gear set but the Bearing Tooth Gear set 130 would have a greatly improve shock tolerance, over that of a conventional gear set, if it were to employ elastomeric structures 132, 147.",
"With a conventional gear set structural failure of the pinion and gear teeth would likely result and if there were no other restrain mechanisms (eg.",
"a winch brake), look out below.",
"Proceeding to FIGS. 9A, 9B and 9C, which shows three views of Bearing Tooth assembly 20 a cross-sectional, isometric and exploded cross-sectional.",
"The following parts show a possible configuration for a Bearing Tooth assembly 20.",
"Bearing Tooth contact structure 1 would be of such a geometry that it would mesh without binding but remain in contact with its mating gear tooth 77 through the entire tooth engagement.",
"Bearing Tooth contact structure 1 could be of greater axial length if longer tooth engagement with mating gear teeth 77 is desired.",
"Support bearing shaft 2 could be an uninterrupted part of, contact structure 1 but the support bearing shaft 2 and contact structure 1 could be made of different materials (eg.",
"elastomers for contact structure 1 and hardened steel for support bearing shaft 2) to obtain different performance characteristics.",
"Inner bearing race 7 would be bonded or mechanically attached to support bearing shaft 2, snap ring 3, seal 4 and top rolling elements 6 and top outer race 5 would need to be installed before the attachment of the inner bearing race 7.",
"The bottom rolling elements 5 and bottom outer race can now be put in place, this collection of parts forms assembly 10, the bearing housing 15 can be slid over assembly 10 and then be secured by snapping snap ring 3 into the snap ring groove 9.",
"The bearing housing 15 would be designed to receive assembly 10 with a close tolerance fit, its exterior circumference would be threaded 11 and be of the right diameter and thread type 11 to interface with its corresponding gear housing's 71 receiving pocket 25.",
"Surfaces 12, 13, 14 and 16 would interface with shims 17 or 18 to maintain the proper separation between Bearing Tooth assembly 20 and the gear housing 71.",
"Building a close tolerance and relatively inexpensive part can be shown by referring to FIGS. 9A, 9B, 9C, &",
"10.",
"In FIGS. 9A, 9B and 9C Bearing Tooth contact structure 1, support bearing shaft 2 and bearing housing 15 are relatively simple "turned"",
"parts where very high tolerances can be obtained.",
"Tolerance envelope 100 would be very small or "tight", for the Bearing Tooth contact structure 1, where tolerances of 10 thousands of an inch, can easily be obtained with such a part.",
"FIG. 10 shows the placement of a Bearing Tooth assembly 20 in it corresponding receiving pocket 25.",
"Accurate hole or receiving pocket 25 placement, is a much easier task to accomplish, than the milling or machining of a complex conventional gear tooth geometry 103 into the outer radius of a gear housing 82.",
"Therefore, tolerance envelope 101 for the Bearing Tooth assembly 20 will be much tighter and easier to control than the conventional gear tooth tolerance envelope 102.",
"With the comparatively less complex parts 1, 2, 15, 25 and the more simplistic manufacturing methods of the Bearing Tooth Gear assembly, tolerancing should be an easier parameter to control, so more accurate gears can be made at lower manufacturing costs.",
"In addition, the rolling action of the Bearing Tooth assembly 20, allows the option of employ displacement and shock tolerant materials 147 (eg.",
"elastomers) or structures 115, 125 (ie.",
"FIG. 11, FIG. 12), which in turn relaxes tolerance requirements.",
"As an example it is quite evident that a pneumatically filled Bearing Tooth 125 can withstand placement and the corresponding engagement inaccuracies better that a ridge, metallic conventional gear tooth 103, whose material strength requirements have created a hard and brittle structure, which has little tolerance to the cyclical shock loading, that would be created by inaccurate tooth geometry, placement or orientation.",
"Lastly, FIGS. 11, 12 &",
"13 demonstrate a Bearing Tooth technology which employs addition methods, for withstanding displacement inaccuracies and high shock loads.",
"FIG. 11 shows a receiving pocket assembly 115, which would be made from displacement and shock tolerant materials 116 (eg.",
"elastomers) and could also employ pneumatically or hydraulically filled cavities 120 which could offer varying shock attenuation and sound abatement performance.",
"The receiving pocket assembly 115 would have a internal ridge receiving pocket 118 which would bond or be mechanically attached to the displacement and shock tolerant material 116 and have a restrain mechanism, such as, being threaded 117 and having internal surface 119 to counter and moment loading.",
"In FIG. 12 the pneumatically or hydraulically filled Bearing Tooth assembly 125 would have the pneumatic or hydraulic fill 128, filling retaining envelope 127 and this retaining envelope 127 would be mounted on a support shaft 126.",
"The support shaft 126 would then interface with the inner bearing race 7, which would interface with rolling element 6 which would interface with outer race 5.",
"The bearing components 5, 6, 7 and the lower portion of support shaft 126 would be housed in the bearing housing 15 as would the seal 4, these components would then be restrained by a snap ring 3, which would be snapped into the snap ring groove 9.",
"The threaded structure 11 of bearing housing 15 would be design to mate with the threads 117 of internal ridge receiving pocket 118, in addition surfaces 12, 13, 14, 19 of bearing housing 15 would closely interface with surface 119 of the receiving pocket.",
"The octagonal bolt head 8 would be used to secure the pneumatically or hydraulically filled Bearing Tooth assembly 125.",
"FIG. 13 shows an isometric of gear assembly 110 which employs pneumatically or hydraulically filled Bearing Tooth assemblies 125 and receiving pocket assemblies 115.",
"The gear housing 111 is bonded or mechanically attached to the displacement and shock tolerant material 116 which is bonded or mechanically attached to internal ridge receiving pocket 118.",
"The pneumatically or hydraulically filled Bearing Tooth assembly 125 would be secured by mating its treads 11 to the threads 117 of the internal ridge receiving pocket 118, the surfaces 13, 19 on the bearing housing 15 would contact the internal surface 119 of the internal ridge receiving pocket 118, the Bearing Tooth assembly 125 would then be tighten to the proper torque specifications, by mating a crescent wrench or like tool to octagonal bolt head 8 on bearing housing 15.",
"Once all of the pneumatically or hydraulically filled Bearing Tooth assemblies 125 are installed, loads could then be applied to the retaining envelope 127, with its pneumatic or hydraulic fill 128 and then to the support shaft 126.",
"The foregoing description of the preferred embodiments of the invention was given for illustrative purposes.",
"These embodiments were not intended to be exhaustive or to limit the invention to the precise forms disclosed.",
"Many modifications, variations and combinations of the above disclosures are possible.",
"It is intended that the scope of the invention not be limited by the detailed description, but rather by the following claims."
] |
This application claims priority to U.S. Provisional Application Ser. No. 61/908,009, filed Nov. 22, 2013, which is incorporated herein by reference.
TECHNICAL FIELD
The present invention relates to communications in general and in particular to the transmission of signals capable of conveying information and detection of those signals in chip-to-chip communication.
BACKGROUND
In communication systems, a goal is to transport information from one physical location to another. It is typically desirable that the transport of this information is reliable, is fast and consumes a minimal amount of resources. One common information transfer medium is the serial communications link, which may be based on a single wire circuit relative to ground or other common reference (i.e., “effective signal ground”), multiple such circuits relative to ground or other common reference, or multiple circuits used in relation to each other. A common example of the latter uses differential signaling (“DS”). Differential signaling operates by sending a signal on one wire and the opposite of that signal on a matching wire. The signal information is represented by the difference between the wires, rather than their absolute values relative to ground or other fixed reference.
There are a number of signaling methods that maintain the desirable properties of DS while increasing pin efficiency over DS. Vector signaling is a method of signaling. With vector signaling, a plurality of signals on a plurality of wires is considered collectively although each of the plurality of signals might be independent. Each of the collective signals is referred to as a component and the number of plurality of wires is referred to as the “dimension” of the vector. In some embodiments, the signal on one wire is entirely dependent on the signal on another wire, as is the case with DS pairs, so in some cases the dimension of the vector might refer to the number of degrees of freedom of signals on the plurality of wires instead of exactly the number of wires in the plurality of wires.
With binary vector signaling, each component or “symbol” of the vector takes on one of two possible values. With non-binary vector signaling, each symbol has a value that is a selection from a set of more than two possible values. Any suitable subset of a vector signaling code denotes a “sub code” of that code. Such a subcode may itself be a vector signaling code.
Examples of vector signaling methods are described in Cronie I, Cronie II, Cronie III, Fox I, Fox II, Fox III, Fox IV, and Holden I.
BRIEF DESCRIPTION
A receiver for vector signaling encoded information accepts multiple wire inputs corresponding to the multiple components of a codeword. Commonly, different voltage, current, etc. levels are used for signaling and more than two levels might be used to represent each codeword element, such as a ternary signaling code wherein each wire signal has one of three values. The receiver may optionally amplify, condition, and filter the received signals and then samples them to provide time-concurrent values which are then analyzed and decoded.
In accordance with at least one embodiment of the invention, circuits are described for the efficient equalization and pre-sample-processing of vector signal coded data transmitted over physical channels such that the signals are resilient to common mode noise, do not require a common reference at the transmission and reception points, and can produce a higher pin efficiency than conventional differential signaling with relatively low power dissipation for encoding and decoding.
As the vector signaling code is communicated by transmission of code elements on each of an ensemble of wires comprising the communications channel, accurate determination of the received code value requires a detector to accurately sample every code element of a code word. Timing skew among these code elements introduces sampling errors. In particular, misalignment of signal transitions on multiple wires presents as transient variations in common mode signal across the ensemble. Continuous-time linear equalization applied to receive signals must not reject this component of the common mode signal as spurious, as it may represent a significant component to be recovered by the samplers.
This Brief Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Brief Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. Other objects and/or advantages of the present invention will be apparent to one of ordinary skill in the art upon review of the Detailed Description and the included drawings.
BRIEF DESCRIPTION OF FIGURES
FIG. 1 is a block diagram of a typical vector signaling code system.
FIG. 2 shows example signal waveforms, illustrating the effect of skew on the common mode signal component of a set of received signals.
FIG. 3A is a schematic diagram of one wire element of the described equalizer, and
FIG. 3B is a schematic diagram of an embodiment of a four wire equalizer.
FIG. 4 is a flow diagram of an embodiment of a method of equalizing signals.
DETAILED DESCRIPTION
An example of a typical systems environment incorporating vector signaling code communication is shown in FIG. 1 . Information to be transmitted 100 is obtained from a source SRC and presented to transmitter 120 . Within the transmitter, the information is encoded 122 as symbols of a vector signaling code 125 , which are then presented to transmit driver 128 , generating physical representations of the code symbols on a collection of wires 145 which together comprise the communications channel 140 .
Receiver 160 accepts physical signals from communications channel 140 , detects the received codewords using, as one example, a collection of differential binary comparators 166 , and then decodes 168 those detected values 167 to obtain the received information 180 output to a destination device DST.
In a practical embodiment, signals 145 may undergo significant change in amplitude, waveform, and other characteristics between emission by transmitter 120 and arrival at receiver 160 , due to the transmission characteristics of communications channel 140 . Therefore, it is common practice to incorporate signal amplification and/or equalization 162 into communications channel receivers. Continuous time linear equalization, also called CTLE, is a known method of providing per-wire equalization in communications systems.
The use of vector signaling code offers the possibility of increased information density, or so-called “pin efficiency” as measured in bits of information transmitted per communications channel wire, as well as immunity from common mode and other noise. As one example, a balanced vector signaling code may be designed to obtain many of the noise immunity benefits of Differential Signaling without its disadvantageous low pin efficiency. However, the need for the receiver to accurately obtain samples representing each element of the transmitted codeword introduces the risk of new types of communications distortion. In particular, differential propagation velocity or “skew” among the various wires may cause different elements of the codeword to arrive at the receiver at different times, even though they were all transmitted simultaneously. Holden I teaches several methods to mitigate the effects of skew in vector signaling code applications.
These known approaches to skew compensation address the temporal aspect of differential arrival times on the receiver by, as an example, separately selecting the sampling time of each wire. Stated differently, these approaches deal with the closing of the receiver eye pattern in the horizontal direction, as a fixed sampling time becomes too early for accurate sampling of some receive signals, and too late for others.
FIG. 2 shows another negative aspect of skew on a vector signaling code receiver. The waveforms for “Transmitted signals” labeled as “Wire 1 ” through “Wire 4 ” represent four example outputs of a vector signaling code transmitter using a ternary (i.e. three level) code over three transmitted symbol intervals. As may be seen, the example code is balanced, in that the sum of all transmitted wire outputs is zero for each symbol interval. This is also seen in the “Common mode” Transmitted signal waveform, which remains essentially zero due to the balanced nature of the transmitted signals.
Seen from the receive end of the communications channel, these same waveforms labeled as “Received signals” are seen to be both attenuated in amplitude, and having significantly slowed rise- and fall-times, due to high frequency attenuation in the channel. Even so, the common mode signal (effectively equivalent to the sum of all received wire signals) is still essentially zero, as the frequency and amplitude distortions are approximately identical for all four wires.
However, this situation changes considerably if a small amount of differential delay occurs, as illustrated in FIG. 2 as “Received signals with skew” where as an example the Wire 2 signal is slightly delayed and the Wire 3 signal is slightly advanced. The early rising edge of Wire 1 no longer coincides with the falling edge of Wire 2 , leading to first a positive peak and then a negative peak in the Common mode signal. Similarly, the offsets between Wire 3 and Wire 4 causes first a slight negative offset followed by a slight positive offset to the Common mode signal.
One familiar with the art would observe that conventional sampling of the skewed waveforms using the Common mode signal as a reference will result in an apparent vertical closing of the receive eye for the Wire signals, as well as the horizontal closing caused by the previously-described timing variations. This effect will be more significant if different sampling times are used for the Wire signals.
A similar result will occur if conventional equalization and common-mode rejection techniques such as continuous time linear equalization and differential common mode amplification are applied on the individual wires, whether subsequent detection is performed differentially between the resulting equalized wire signals or individually on each wire. Common practice for an analog equalizer, as one example in a differential signaling application, relies on a differential transistor pair with parallel-RC source degeneration. Such a circuit provides equalization of the differential signal through a zero-pole pair, while also rejecting the common-mode signal completely.
Continuous time linear equalizer with controlled common mode rejection
As previously described, if continuous-time linear equalization is required to compensate for channel losses, the equalizer must not reject the common-mode signals that appear as a result of channel skew, because it represents a part of the signal to be recovered by the sampler/de-skew circuit.
The component of the common-mode signal caused by channel skew is band-limited, has zero mean, and appears only around transitions of the transmitted signal. It is therefore desirable to implement a linear equalizer that passes common-mode signals in the frequency band of interest, and rejects low-frequency common-mode signals, such as are associated with induced noise.
FIGS. 3A , 3 B illustrate a circuit providing the desired equalization with controlled common mode rejection for an arbitrary number of channel signals. For descriptive purposes, the schematic of FIG. 3A is drawn in the style of a differential pair, accepting two inputs Input 1 and Input 2 and producing two outputs Output 1 and Output 2 . However, the fundamental circuit element 300 is intended to be replicated as required to support additional inputs, thus the example may be extended to support an arbitrary number of inputs and outputs. As a specific example, FIG. 3B shows an embodiment in which the circuit of FIG. 3A has been extended to support four inputs and provide four outputs.
In FIG. 3A , transistors Q 1 and Q 2 are a matched pair, accepting Input 1 and Input 2 , and generating Output 1 and Output 2 across their respective loads RL. Unlike a conventional differential amplifier having a shared source current sink, each of Q 1 and Q 2 has its own current sink, as well as parallel RC network Rd and Cd connecting to the Shared node that has capacitance Cc to ground.
If Cd<<Cc, the desired low-frequency common mode behavior can be understood by discarding Cd. Starting at f=0, the circuit is a type of “generalized differential pair”, consisting of N transistors (with biasing current source) with their source nodes connected together by a star network of N resistors of value Rd. This circuit has a small-signal (differential) gain of RL/Rd in the general case. In this region of operation, common mode signals such as noise are suppressed by the differential amplifier behavior of the circuit.
Above the cutoff frequency or corner frequency 1/(2pi*(Rd/N)*Cc), the capacitor Cc has low impedance, and the circuit therefore presents as N independent single-ended common source amplifiers with a source degeneration Rd. In this region of operation, common mode signals as are caused by skew are not suppressed. It is understood that the transition between these two regions is gradual, and that the cutoff frequency terminology refers to a characteristic (a so-called 3-dB point) of the transition between these frequency regions. References to conveying signals in one region while shunting signals in another region should not be interpreted as a binary, or even rapid transition between regions, but rather a gradual transition as is know in the electrical arts.
As a result, this circuit rejects the common-mode signal at low frequency and passes it at high frequency. This makes the circuit work correctly in the case of skew in the channel, which causes a high-frequency common-mode signal to appear that, if suppressed, would reduce detection margins.
At even higher frequencies, above around 1/(2pi*Rd*Cd) the resistor is effectively short-circuited by the capacitor Cd, and the gain rises to gm*RL, where gm is the transistor transconductance. The Rd/Cd network thus adds a zero-pole pair with a peaking of gm*Rd. In this region of operation, the circuit acts as a high-frequency equalizer. Note that in some embodiments, Cd and the signal peaking it provides may not be needed or desired, and may be omitted.
As previously described, the fundamental circuit element 300 is intended to be replicated as required to support additional inputs, thus the examples presented explicitly include an arbitrary number of inputs and outputs. In such cases, each of the multiple instances of 300 are intended to be identical, with all transistors matching, all named component values in common, and the calculated value of Cc scaling with N, as indicated by the corner frequency examples above. As a specific example, FIG. 3B shows the circuit of FIG. 3A extended to support four inputs and provide four outputs, using four matched transistors in an extended differential amplifier design.
An embodiment incorporating the circuit of FIG. 3B in front-end processing for a vector signaling code receiver maintains outputs having the necessary components of the common-mode signal to minimize skew related amplitude error. A further embodiment also incorporating a multi-wire sampler with adjustable sampling clock phase per wire also provides compensation for the temporal component of input skew error, resulting in an undistorted representation of the received codeword. Other embodiments combine fewer or more instances of circuit element 300 and samplers with adjustable clock phase per wire, to provide equivalent amplitude and temporal skew compensation for reception of shorter or longer codewords.
Therefore, in one embodiment, the circuit comprises a plurality of transistors, each transistor of the plurality of transistors having (i) an input node connected to a respective wire of a multi-wire communication medium, (ii) a drain-connected load impedance, (iii) a transistor drain signal output node, (iv) a transistor source node and (v) a source-connected current sink; a plurality of degeneration impedances, each separately connecting respective transistor sources to a common node; and, a common node capacitance connected to the common node and to effective signal ground, having a frequency-selective coupling to the effective signal ground, and configured to provide common mode negative feedback signals to the plurality of transistors for common mode signals in a first frequency range and to shunt common mode signals to the effective signal ground for common mode signals in a second frequency range.
The load impedance is either purely resistive, inductive, or provided by a combined resistor and inductor circuit network. The degeneration impedance may comprise a parallel resistor and capacitor network. In some embodiments, the degeneration impedance is frequency selective to provide increased amplifier gain for frequencies above a predetermined peaking frequency. The apparatus may comprise one or more signal comparators connected to outputs of the multi-input amplifier, where the wires of the multi-wire communication medium convey signals of a balanced vector signaling code to the inputs.
In a further embodiment, the apparatus may comprise a multi-wire communications medium comprising a plurality of wires; a multi-input amplifier having a plurality of amplifier branches, each amplifier branch of the plurality of amplifier branches connected a respective wire of the multi-wire communications medium; a frequency-selective common mode impedance electrically interconnecting the plurality of amplifier branches in a differential amplifier configuration for signals below a first cutoff frequency and electrically isolating the plurality of amplifier branches in a non-differential amplifier configuration for signals above a first cutoff frequency.
In an embodiment, the first cutoff frequency is configured to provide greater than 6 dB of attenuation of frequencies approximately equal to 1/(2Tskew), where Tskew is a maximum timing offset between signal pulses applied to respective transistor amplifiers. In a further embodiment, the plurality of source-connected degeneration impedances is frequency selective and provides reduced impedance magnitude at higher frequencies to provide high frequency signal peaking.
With respect to FIG. 4 , a method 400 will be described. At block 402 , signals are received from a plurality of wires of a multi-wire communications medium. The signals are received by the multi-input amplifier, where each input is associated with a branch of the amplifier. Using the frequency-selective common node impedance, the circuit conveys ( 402 ) low-frequency common mode signals as common mode negative feedback to the plurality of amplifier branches. The signals are conveyed due to the higher magnitude of the real part of the common node impedance, which provides signal isolation with respect to the effective signal ground node. Note that low-frequency common mode signals are those that are below the cutoff frequency. At 404 , the circuit, via the frequency-selective common node impedance, shunts the common mode signals having a frequency above the cutoff frequency to effective signal ground. This causes the multi-input amplifier to behave as independent single ended amplifiers with respect to higher frequencies, rather than as a differential amplifier with common mode rejection.
The method 400 may further comprise increasing the amplifier gain of each amplifier branch as a function of frequency by decreasing a magnitude of a high-frequency impedance component of the degeneration impedances in the amplifier branches. The degeneration impedances include a capacitor in the degeneration impedance. In some embodiments, the degeneration impedance comprises a parallel resistor and capacitor network, such as one or more capacitors in parallel with one or mode resistors. In some embodiments, the capacitors and/or the resistor elements are switchable to provide a tunable impedance. In some embodiments, the circuit includes a training controller for iteratively adjusting the impedance values and determining a cutoff frequency that improve a performance metric. In one embodiment, a bit or frame error rate may be monitored as the training controller adjusts the impedance values of the common node impedance.
The method 400 may further comprise sampling output signals of the amplifier branches using time instants that offset differential input delays. In some embodiments, the circuit includes a training controller for iteratively adjusting the timing instants and determining timing instants that improve a performance metric. In one embodiment, a bit or frame error rate may be monitored as the training controller adjusts the timing of the sampling instants.
In further embodiments, the method 400 may further comprise applying outputs of the amplifier branches to a plurality of comparators.
Further Embodiments
It should be noted that placement of the current sink at each transistor's source, rather than at the shared node as is common practice, allows degeneration resistor Rd to remain outside of the DC current path. Thus, unlike in a conventional differential stage, the presence of Rd does not result in a loss of amplifier headroom.
In a practical embodiment, the multiple instances of FIG. 3 's circuit element 300 may be physically distant in the integrated circuit design, requiring the common node signal line to span those elements. However, as the common node by design has a capacitance to ground, the resulting introduction of parasitic capacitance due to wire routing need not be an issue, as the parasitic capacitance may be factored into the overall Cc value.
Some embodiments of the circuit of FIG. 3 may allow one or more component to be adjustable or trimmable. As one example, Rd and/or Cd can be adjusted to set the position of the zero and pole, as in a classical differential analog equalizer. Switching parallel or serial R or C elements into and out of the circuit using pass transistors or CMOS analog switches may perform such adjustment, as one example.
The value of Cc is usually be set by design, by considering the lowest frequency components of the common-mode signal, which in turn depends on the amount of skew in the system. If Rd is being adjusted, it might be necessary to adjust Cc as well, if it is desired that the common-mode cutoff frequency remains the same.
One further embodiment eliminates the degeneration impedance 1/(2pi*Rd*Cd) from each transistor source (that is, connecting each source to the common node with Cc to ground) resulting in a circuit acting as a hybrid, transitioning from a generalized differential amplifier with N inputs to N single-ended common-source amplifiers at a transition frequency of approximately gm//(2pi*Cc). A similar embodiment incorporates Rd and Cc without Cd. In such an embodiment, the low-frequency common mode rejection is provided, as well as the non-differential high frequency amplification, but the higher frequency signal peaking is not.
Another embodiment replaces load resistors RL with an inductor or inductor and resistor combination to provide additional frequency peaking, as is common practice. Another embodiment replaces or augments load resistors RL with a current mirror or other known active load structure, either as an explicit transistor loading element, or as part of the circuitry receiving an Output signal, thus effectively being in parallel with the described load RL.
At least one embodiment combines the described continuous time linear equalization with time-based skew compensation that adjusts the sampling time of each wire to compensate for differential signal arrival times.
Although illustrated as part of a system utilizing a balanced vector signaling code, the described embodiments may be used in any receiver application where the input signal or signals do not have an appreciable transmitted common mode component, one such example being a system using differential signaling.
The examples illustrate the use of vector signaling codes for point-to-point wire communications. However, this should not been seen in any way as limiting the scope of the described invention. The methods disclosed in this application are equally applicable to other encoding methods, and to communication media including optical and wireless communications. Thus, descriptive terms such as “voltage” or “signal level” should be considered to include both electrical equivalents such as “current”, and also equivalents in other measurement systems, such as “optical intensity”, “RF modulation”, etc. Similarly, specific examples provided herein are for purposes of description, and do not imply a limitation.
As used herein, “physical signal” includes any suitable behavior and/or attribute of a physical phenomenon capable of conveying information. In accordance with at least one embodiment of the invention, physical signals may be tangible and non-transitory.
REFERENCES
The following references are herein incorporated by reference in their entirety for all purposes:
U.S. Patent Publication No. 2011/0268225 of U.S. patent application Ser. No. 12/784,414, filed May 20, 2010, naming Harm Cronie and Amin Shokrollahi, entitled “Orthogonal Differential Vector Signaling” (herein “Cronie I”);
U.S. Patent Publication No. 2011/0302478 of U.S. patent application Ser. No. 12/982,777, filed Dec. 30, 2010, naming Harm Cronie and Amin Shokrollahi, entitled “Power and Pin Efficient Chip-to-Chip Communications with Common-Mode Resilience and SSO Resilience” (herein “Cronie II”);
U.S. patent application Ser. No. 13/030,027, filed Feb. 17, 2011, naming Harm Cronie, Amin Shokrollahi and Armin Tajalli, entitled “Methods and Systems for Noise Resilient, Pin-Efficient and Low Power Communications with Sparse Signaling Codes” (herein “Cronie III”);
U.S. Provisional Patent Application No. 61/753,870, filed Jan. 17, 2013, naming John Fox, Brian Holden, Peter Hunt, John D Keay, Amin Shokrollahi, Richard Simpson, Anant Singh, Andrew Kevin John Stewart, and Giuseppe Surace, entitled “Methods and Systems for Chip-to-chip Communication with Reduced Simultaneous Switching Noise” (herein called “Fox I”);
U.S. Provisional Patent Application No. 61/763,403, filed Feb. 11, 2013, naming John Fox, Brian Holden, Ali Hormati, Peter Hunt, John D Keay, Amin Shokrollahi, Anant Singh, Andrew Kevin John Stewart, Giuseppe Surace, and Roger Ulrich, entitled “Methods and Systems for High Bandwidth Chip-to-Chip Communications Interface” (herein called “Fox II”);
U.S. Provisional Patent Application No. 61/773,709, filed Mar. 6, 2013, naming John Fox, Brian Holden, Peter Hunt, John D Keay, Amin Shokrollahi, Andrew Kevin John Stewart, Giuseppe Surace, and Roger Ulrich, entitled “Methods and Systems for High Bandwidth Chip-to-Chip Communications Interface” (herein called “Fox III”);
U.S. Provisional Patent Application No. 61/812,667, filed Apr. 16, 2013, naming John Fox, Brian Holden, Ali Hormati, Peter Hunt, John D Keay, Amin Shokrollahi, Anant Singh, Andrew Kevin John Stewart, and Giuseppe Surace, entitled “Methods and Systems for High Bandwidth Communications Interface” (herein called “Fox IV”);
U.S. patent application Ser. No. 13/842,740, filed Mar. 15, 2013, naming Brian Holden, Amin Shokrollahi, and Anant Singh, entitled “Methods and Systems for Skew Tolerance in and Advanced Detectors for Vector Signaling Codes for Chip-to-Chip Communication” (herein called “Holden I”);
U.S. patent application Ser. No. 13/895,206, filed May 15, 2013, naming Roger Ulrich and Peter Hunt, entitled “Circuits for Efficient Detection of Vector Signaling Codes for Chip-to-Chip Communications using Sums of Differences” (herein called “Ulrich I”). | Continuous-time linear equalization of received signals on multiple wire channels while maintaining accurate common mode signal values. Multiwire group signaling using vector signaling codes simultaneously transmits encoded values on multiple wires, requiring multiple receive signals to be sampled simultaneously to retrieve the full transmitted code word. By misaligning transitions on multiple wires, skew introduces a transient common mode signal component that is preserved by using frequency-selective common mode feedback at the receiver to obtain accurate sampling results. | Identify the most important aspect in the document and summarize the concept accordingly. | [
"This application claims priority to U.S. Provisional Application Ser.",
"No. 61/908,009, filed Nov. 22, 2013, which is incorporated herein by reference.",
"TECHNICAL FIELD The present invention relates to communications in general and in particular to the transmission of signals capable of conveying information and detection of those signals in chip-to-chip communication.",
"BACKGROUND In communication systems, a goal is to transport information from one physical location to another.",
"It is typically desirable that the transport of this information is reliable, is fast and consumes a minimal amount of resources.",
"One common information transfer medium is the serial communications link, which may be based on a single wire circuit relative to ground or other common reference (i.e., “effective signal ground”), multiple such circuits relative to ground or other common reference, or multiple circuits used in relation to each other.",
"A common example of the latter uses differential signaling (“DS”).",
"Differential signaling operates by sending a signal on one wire and the opposite of that signal on a matching wire.",
"The signal information is represented by the difference between the wires, rather than their absolute values relative to ground or other fixed reference.",
"There are a number of signaling methods that maintain the desirable properties of DS while increasing pin efficiency over DS.",
"Vector signaling is a method of signaling.",
"With vector signaling, a plurality of signals on a plurality of wires is considered collectively although each of the plurality of signals might be independent.",
"Each of the collective signals is referred to as a component and the number of plurality of wires is referred to as the “dimension”",
"of the vector.",
"In some embodiments, the signal on one wire is entirely dependent on the signal on another wire, as is the case with DS pairs, so in some cases the dimension of the vector might refer to the number of degrees of freedom of signals on the plurality of wires instead of exactly the number of wires in the plurality of wires.",
"With binary vector signaling, each component or “symbol”",
"of the vector takes on one of two possible values.",
"With non-binary vector signaling, each symbol has a value that is a selection from a set of more than two possible values.",
"Any suitable subset of a vector signaling code denotes a “sub code”",
"of that code.",
"Such a subcode may itself be a vector signaling code.",
"Examples of vector signaling methods are described in Cronie I, Cronie II, Cronie III, Fox I, Fox II, Fox III, Fox IV, and Holden I. BRIEF DESCRIPTION A receiver for vector signaling encoded information accepts multiple wire inputs corresponding to the multiple components of a codeword.",
"Commonly, different voltage, current, etc.",
"levels are used for signaling and more than two levels might be used to represent each codeword element, such as a ternary signaling code wherein each wire signal has one of three values.",
"The receiver may optionally amplify, condition, and filter the received signals and then samples them to provide time-concurrent values which are then analyzed and decoded.",
"In accordance with at least one embodiment of the invention, circuits are described for the efficient equalization and pre-sample-processing of vector signal coded data transmitted over physical channels such that the signals are resilient to common mode noise, do not require a common reference at the transmission and reception points, and can produce a higher pin efficiency than conventional differential signaling with relatively low power dissipation for encoding and decoding.",
"As the vector signaling code is communicated by transmission of code elements on each of an ensemble of wires comprising the communications channel, accurate determination of the received code value requires a detector to accurately sample every code element of a code word.",
"Timing skew among these code elements introduces sampling errors.",
"In particular, misalignment of signal transitions on multiple wires presents as transient variations in common mode signal across the ensemble.",
"Continuous-time linear equalization applied to receive signals must not reject this component of the common mode signal as spurious, as it may represent a significant component to be recovered by the samplers.",
"This Brief Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description.",
"This Brief Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.",
"Other objects and/or advantages of the present invention will be apparent to one of ordinary skill in the art upon review of the Detailed Description and the included drawings.",
"BRIEF DESCRIPTION OF FIGURES FIG. 1 is a block diagram of a typical vector signaling code system.",
"FIG. 2 shows example signal waveforms, illustrating the effect of skew on the common mode signal component of a set of received signals.",
"FIG. 3A is a schematic diagram of one wire element of the described equalizer, and FIG. 3B is a schematic diagram of an embodiment of a four wire equalizer.",
"FIG. 4 is a flow diagram of an embodiment of a method of equalizing signals.",
"DETAILED DESCRIPTION An example of a typical systems environment incorporating vector signaling code communication is shown in FIG. 1 .",
"Information to be transmitted 100 is obtained from a source SRC and presented to transmitter 120 .",
"Within the transmitter, the information is encoded 122 as symbols of a vector signaling code 125 , which are then presented to transmit driver 128 , generating physical representations of the code symbols on a collection of wires 145 which together comprise the communications channel 140 .",
"Receiver 160 accepts physical signals from communications channel 140 , detects the received codewords using, as one example, a collection of differential binary comparators 166 , and then decodes 168 those detected values 167 to obtain the received information 180 output to a destination device DST.",
"In a practical embodiment, signals 145 may undergo significant change in amplitude, waveform, and other characteristics between emission by transmitter 120 and arrival at receiver 160 , due to the transmission characteristics of communications channel 140 .",
"Therefore, it is common practice to incorporate signal amplification and/or equalization 162 into communications channel receivers.",
"Continuous time linear equalization, also called CTLE, is a known method of providing per-wire equalization in communications systems.",
"The use of vector signaling code offers the possibility of increased information density, or so-called “pin efficiency”",
"as measured in bits of information transmitted per communications channel wire, as well as immunity from common mode and other noise.",
"As one example, a balanced vector signaling code may be designed to obtain many of the noise immunity benefits of Differential Signaling without its disadvantageous low pin efficiency.",
"However, the need for the receiver to accurately obtain samples representing each element of the transmitted codeword introduces the risk of new types of communications distortion.",
"In particular, differential propagation velocity or “skew”",
"among the various wires may cause different elements of the codeword to arrive at the receiver at different times, even though they were all transmitted simultaneously.",
"Holden I teaches several methods to mitigate the effects of skew in vector signaling code applications.",
"These known approaches to skew compensation address the temporal aspect of differential arrival times on the receiver by, as an example, separately selecting the sampling time of each wire.",
"Stated differently, these approaches deal with the closing of the receiver eye pattern in the horizontal direction, as a fixed sampling time becomes too early for accurate sampling of some receive signals, and too late for others.",
"FIG. 2 shows another negative aspect of skew on a vector signaling code receiver.",
"The waveforms for “Transmitted signals”",
"labeled as “Wire 1 ”",
"through “Wire 4 ”",
"represent four example outputs of a vector signaling code transmitter using a ternary (i.e. three level) code over three transmitted symbol intervals.",
"As may be seen, the example code is balanced, in that the sum of all transmitted wire outputs is zero for each symbol interval.",
"This is also seen in the “Common mode”",
"Transmitted signal waveform, which remains essentially zero due to the balanced nature of the transmitted signals.",
"Seen from the receive end of the communications channel, these same waveforms labeled as “Received signals”",
"are seen to be both attenuated in amplitude, and having significantly slowed rise- and fall-times, due to high frequency attenuation in the channel.",
"Even so, the common mode signal (effectively equivalent to the sum of all received wire signals) is still essentially zero, as the frequency and amplitude distortions are approximately identical for all four wires.",
"However, this situation changes considerably if a small amount of differential delay occurs, as illustrated in FIG. 2 as “Received signals with skew”",
"where as an example the Wire 2 signal is slightly delayed and the Wire 3 signal is slightly advanced.",
"The early rising edge of Wire 1 no longer coincides with the falling edge of Wire 2 , leading to first a positive peak and then a negative peak in the Common mode signal.",
"Similarly, the offsets between Wire 3 and Wire 4 causes first a slight negative offset followed by a slight positive offset to the Common mode signal.",
"One familiar with the art would observe that conventional sampling of the skewed waveforms using the Common mode signal as a reference will result in an apparent vertical closing of the receive eye for the Wire signals, as well as the horizontal closing caused by the previously-described timing variations.",
"This effect will be more significant if different sampling times are used for the Wire signals.",
"A similar result will occur if conventional equalization and common-mode rejection techniques such as continuous time linear equalization and differential common mode amplification are applied on the individual wires, whether subsequent detection is performed differentially between the resulting equalized wire signals or individually on each wire.",
"Common practice for an analog equalizer, as one example in a differential signaling application, relies on a differential transistor pair with parallel-RC source degeneration.",
"Such a circuit provides equalization of the differential signal through a zero-pole pair, while also rejecting the common-mode signal completely.",
"Continuous time linear equalizer with controlled common mode rejection As previously described, if continuous-time linear equalization is required to compensate for channel losses, the equalizer must not reject the common-mode signals that appear as a result of channel skew, because it represents a part of the signal to be recovered by the sampler/de-skew circuit.",
"The component of the common-mode signal caused by channel skew is band-limited, has zero mean, and appears only around transitions of the transmitted signal.",
"It is therefore desirable to implement a linear equalizer that passes common-mode signals in the frequency band of interest, and rejects low-frequency common-mode signals, such as are associated with induced noise.",
"FIGS. 3A , 3 B illustrate a circuit providing the desired equalization with controlled common mode rejection for an arbitrary number of channel signals.",
"For descriptive purposes, the schematic of FIG. 3A is drawn in the style of a differential pair, accepting two inputs Input 1 and Input 2 and producing two outputs Output 1 and Output 2 .",
"However, the fundamental circuit element 300 is intended to be replicated as required to support additional inputs, thus the example may be extended to support an arbitrary number of inputs and outputs.",
"As a specific example, FIG. 3B shows an embodiment in which the circuit of FIG. 3A has been extended to support four inputs and provide four outputs.",
"In FIG. 3A , transistors Q 1 and Q 2 are a matched pair, accepting Input 1 and Input 2 , and generating Output 1 and Output 2 across their respective loads RL.",
"Unlike a conventional differential amplifier having a shared source current sink, each of Q 1 and Q 2 has its own current sink, as well as parallel RC network Rd and Cd connecting to the Shared node that has capacitance Cc to ground.",
"If Cd<<Cc, the desired low-frequency common mode behavior can be understood by discarding Cd.",
"Starting at f=0, the circuit is a type of “generalized differential pair”, consisting of N transistors (with biasing current source) with their source nodes connected together by a star network of N resistors of value Rd.",
"This circuit has a small-signal (differential) gain of RL/Rd in the general case.",
"In this region of operation, common mode signals such as noise are suppressed by the differential amplifier behavior of the circuit.",
"Above the cutoff frequency or corner frequency 1/(2pi*(Rd/N)*Cc), the capacitor Cc has low impedance, and the circuit therefore presents as N independent single-ended common source amplifiers with a source degeneration Rd.",
"In this region of operation, common mode signals as are caused by skew are not suppressed.",
"It is understood that the transition between these two regions is gradual, and that the cutoff frequency terminology refers to a characteristic (a so-called 3-dB point) of the transition between these frequency regions.",
"References to conveying signals in one region while shunting signals in another region should not be interpreted as a binary, or even rapid transition between regions, but rather a gradual transition as is know in the electrical arts.",
"As a result, this circuit rejects the common-mode signal at low frequency and passes it at high frequency.",
"This makes the circuit work correctly in the case of skew in the channel, which causes a high-frequency common-mode signal to appear that, if suppressed, would reduce detection margins.",
"At even higher frequencies, above around 1/(2pi*Rd*Cd) the resistor is effectively short-circuited by the capacitor Cd, and the gain rises to gm*RL, where gm is the transistor transconductance.",
"The Rd/Cd network thus adds a zero-pole pair with a peaking of gm*Rd.",
"In this region of operation, the circuit acts as a high-frequency equalizer.",
"Note that in some embodiments, Cd and the signal peaking it provides may not be needed or desired, and may be omitted.",
"As previously described, the fundamental circuit element 300 is intended to be replicated as required to support additional inputs, thus the examples presented explicitly include an arbitrary number of inputs and outputs.",
"In such cases, each of the multiple instances of 300 are intended to be identical, with all transistors matching, all named component values in common, and the calculated value of Cc scaling with N, as indicated by the corner frequency examples above.",
"As a specific example, FIG. 3B shows the circuit of FIG. 3A extended to support four inputs and provide four outputs, using four matched transistors in an extended differential amplifier design.",
"An embodiment incorporating the circuit of FIG. 3B in front-end processing for a vector signaling code receiver maintains outputs having the necessary components of the common-mode signal to minimize skew related amplitude error.",
"A further embodiment also incorporating a multi-wire sampler with adjustable sampling clock phase per wire also provides compensation for the temporal component of input skew error, resulting in an undistorted representation of the received codeword.",
"Other embodiments combine fewer or more instances of circuit element 300 and samplers with adjustable clock phase per wire, to provide equivalent amplitude and temporal skew compensation for reception of shorter or longer codewords.",
"Therefore, in one embodiment, the circuit comprises a plurality of transistors, each transistor of the plurality of transistors having (i) an input node connected to a respective wire of a multi-wire communication medium, (ii) a drain-connected load impedance, (iii) a transistor drain signal output node, (iv) a transistor source node and (v) a source-connected current sink;",
"a plurality of degeneration impedances, each separately connecting respective transistor sources to a common node;",
"and, a common node capacitance connected to the common node and to effective signal ground, having a frequency-selective coupling to the effective signal ground, and configured to provide common mode negative feedback signals to the plurality of transistors for common mode signals in a first frequency range and to shunt common mode signals to the effective signal ground for common mode signals in a second frequency range.",
"The load impedance is either purely resistive, inductive, or provided by a combined resistor and inductor circuit network.",
"The degeneration impedance may comprise a parallel resistor and capacitor network.",
"In some embodiments, the degeneration impedance is frequency selective to provide increased amplifier gain for frequencies above a predetermined peaking frequency.",
"The apparatus may comprise one or more signal comparators connected to outputs of the multi-input amplifier, where the wires of the multi-wire communication medium convey signals of a balanced vector signaling code to the inputs.",
"In a further embodiment, the apparatus may comprise a multi-wire communications medium comprising a plurality of wires;",
"a multi-input amplifier having a plurality of amplifier branches, each amplifier branch of the plurality of amplifier branches connected a respective wire of the multi-wire communications medium;",
"a frequency-selective common mode impedance electrically interconnecting the plurality of amplifier branches in a differential amplifier configuration for signals below a first cutoff frequency and electrically isolating the plurality of amplifier branches in a non-differential amplifier configuration for signals above a first cutoff frequency.",
"In an embodiment, the first cutoff frequency is configured to provide greater than 6 dB of attenuation of frequencies approximately equal to 1/(2Tskew), where Tskew is a maximum timing offset between signal pulses applied to respective transistor amplifiers.",
"In a further embodiment, the plurality of source-connected degeneration impedances is frequency selective and provides reduced impedance magnitude at higher frequencies to provide high frequency signal peaking.",
"With respect to FIG. 4 , a method 400 will be described.",
"At block 402 , signals are received from a plurality of wires of a multi-wire communications medium.",
"The signals are received by the multi-input amplifier, where each input is associated with a branch of the amplifier.",
"Using the frequency-selective common node impedance, the circuit conveys ( 402 ) low-frequency common mode signals as common mode negative feedback to the plurality of amplifier branches.",
"The signals are conveyed due to the higher magnitude of the real part of the common node impedance, which provides signal isolation with respect to the effective signal ground node.",
"Note that low-frequency common mode signals are those that are below the cutoff frequency.",
"At 404 , the circuit, via the frequency-selective common node impedance, shunts the common mode signals having a frequency above the cutoff frequency to effective signal ground.",
"This causes the multi-input amplifier to behave as independent single ended amplifiers with respect to higher frequencies, rather than as a differential amplifier with common mode rejection.",
"The method 400 may further comprise increasing the amplifier gain of each amplifier branch as a function of frequency by decreasing a magnitude of a high-frequency impedance component of the degeneration impedances in the amplifier branches.",
"The degeneration impedances include a capacitor in the degeneration impedance.",
"In some embodiments, the degeneration impedance comprises a parallel resistor and capacitor network, such as one or more capacitors in parallel with one or mode resistors.",
"In some embodiments, the capacitors and/or the resistor elements are switchable to provide a tunable impedance.",
"In some embodiments, the circuit includes a training controller for iteratively adjusting the impedance values and determining a cutoff frequency that improve a performance metric.",
"In one embodiment, a bit or frame error rate may be monitored as the training controller adjusts the impedance values of the common node impedance.",
"The method 400 may further comprise sampling output signals of the amplifier branches using time instants that offset differential input delays.",
"In some embodiments, the circuit includes a training controller for iteratively adjusting the timing instants and determining timing instants that improve a performance metric.",
"In one embodiment, a bit or frame error rate may be monitored as the training controller adjusts the timing of the sampling instants.",
"In further embodiments, the method 400 may further comprise applying outputs of the amplifier branches to a plurality of comparators.",
"Further Embodiments It should be noted that placement of the current sink at each transistor's source, rather than at the shared node as is common practice, allows degeneration resistor Rd to remain outside of the DC current path.",
"Thus, unlike in a conventional differential stage, the presence of Rd does not result in a loss of amplifier headroom.",
"In a practical embodiment, the multiple instances of FIG. 3 's circuit element 300 may be physically distant in the integrated circuit design, requiring the common node signal line to span those elements.",
"However, as the common node by design has a capacitance to ground, the resulting introduction of parasitic capacitance due to wire routing need not be an issue, as the parasitic capacitance may be factored into the overall Cc value.",
"Some embodiments of the circuit of FIG. 3 may allow one or more component to be adjustable or trimmable.",
"As one example, Rd and/or Cd can be adjusted to set the position of the zero and pole, as in a classical differential analog equalizer.",
"Switching parallel or serial R or C elements into and out of the circuit using pass transistors or CMOS analog switches may perform such adjustment, as one example.",
"The value of Cc is usually be set by design, by considering the lowest frequency components of the common-mode signal, which in turn depends on the amount of skew in the system.",
"If Rd is being adjusted, it might be necessary to adjust Cc as well, if it is desired that the common-mode cutoff frequency remains the same.",
"One further embodiment eliminates the degeneration impedance 1/(2pi*Rd*Cd) from each transistor source (that is, connecting each source to the common node with Cc to ground) resulting in a circuit acting as a hybrid, transitioning from a generalized differential amplifier with N inputs to N single-ended common-source amplifiers at a transition frequency of approximately gm//(2pi*Cc).",
"A similar embodiment incorporates Rd and Cc without Cd.",
"In such an embodiment, the low-frequency common mode rejection is provided, as well as the non-differential high frequency amplification, but the higher frequency signal peaking is not.",
"Another embodiment replaces load resistors RL with an inductor or inductor and resistor combination to provide additional frequency peaking, as is common practice.",
"Another embodiment replaces or augments load resistors RL with a current mirror or other known active load structure, either as an explicit transistor loading element, or as part of the circuitry receiving an Output signal, thus effectively being in parallel with the described load RL.",
"At least one embodiment combines the described continuous time linear equalization with time-based skew compensation that adjusts the sampling time of each wire to compensate for differential signal arrival times.",
"Although illustrated as part of a system utilizing a balanced vector signaling code, the described embodiments may be used in any receiver application where the input signal or signals do not have an appreciable transmitted common mode component, one such example being a system using differential signaling.",
"The examples illustrate the use of vector signaling codes for point-to-point wire communications.",
"However, this should not been seen in any way as limiting the scope of the described invention.",
"The methods disclosed in this application are equally applicable to other encoding methods, and to communication media including optical and wireless communications.",
"Thus, descriptive terms such as “voltage”",
"or “signal level”",
"should be considered to include both electrical equivalents such as “current”, and also equivalents in other measurement systems, such as “optical intensity”, “RF modulation”, etc.",
"Similarly, specific examples provided herein are for purposes of description, and do not imply a limitation.",
"As used herein, “physical signal”",
"includes any suitable behavior and/or attribute of a physical phenomenon capable of conveying information.",
"In accordance with at least one embodiment of the invention, physical signals may be tangible and non-transitory.",
"REFERENCES The following references are herein incorporated by reference in their entirety for all purposes: U.S. Patent Publication No. 2011/0268225 of U.S. patent application Ser.",
"No. 12/784,414, filed May 20, 2010, naming Harm Cronie and Amin Shokrollahi, entitled “Orthogonal Differential Vector Signaling”",
"(herein “Cronie I”);",
"U.S. Patent Publication No. 2011/0302478 of U.S. patent application Ser.",
"No. 12/982,777, filed Dec. 30, 2010, naming Harm Cronie and Amin Shokrollahi, entitled “Power and Pin Efficient Chip-to-Chip Communications with Common-Mode Resilience and SSO Resilience”",
"(herein “Cronie II”);",
"U.S. patent application Ser.",
"No. 13/030,027, filed Feb. 17, 2011, naming Harm Cronie, Amin Shokrollahi and Armin Tajalli, entitled “Methods and Systems for Noise Resilient, Pin-Efficient and Low Power Communications with Sparse Signaling Codes”",
"(herein “Cronie III”);",
"U.S. Provisional Patent Application No. 61/753,870, filed Jan. 17, 2013, naming John Fox, Brian Holden, Peter Hunt, John D Keay, Amin Shokrollahi, Richard Simpson, Anant Singh, Andrew Kevin John Stewart, and Giuseppe Surace, entitled “Methods and Systems for Chip-to-chip Communication with Reduced Simultaneous Switching Noise”",
"(herein called “Fox I”);",
"U.S. Provisional Patent Application No. 61/763,403, filed Feb. 11, 2013, naming John Fox, Brian Holden, Ali Hormati, Peter Hunt, John D Keay, Amin Shokrollahi, Anant Singh, Andrew Kevin John Stewart, Giuseppe Surace, and Roger Ulrich, entitled “Methods and Systems for High Bandwidth Chip-to-Chip Communications Interface”",
"(herein called “Fox II”);",
"U.S. Provisional Patent Application No. 61/773,709, filed Mar. 6, 2013, naming John Fox, Brian Holden, Peter Hunt, John D Keay, Amin Shokrollahi, Andrew Kevin John Stewart, Giuseppe Surace, and Roger Ulrich, entitled “Methods and Systems for High Bandwidth Chip-to-Chip Communications Interface”",
"(herein called “Fox III”);",
"U.S. Provisional Patent Application No. 61/812,667, filed Apr. 16, 2013, naming John Fox, Brian Holden, Ali Hormati, Peter Hunt, John D Keay, Amin Shokrollahi, Anant Singh, Andrew Kevin John Stewart, and Giuseppe Surace, entitled “Methods and Systems for High Bandwidth Communications Interface”",
"(herein called “Fox IV”);",
"U.S. patent application Ser.",
"No. 13/842,740, filed Mar. 15, 2013, naming Brian Holden, Amin Shokrollahi, and Anant Singh, entitled “Methods and Systems for Skew Tolerance in and Advanced Detectors for Vector Signaling Codes for Chip-to-Chip Communication”",
"(herein called “Holden I”);",
"U.S. patent application Ser.",
"No. 13/895,206, filed May 15, 2013, naming Roger Ulrich and Peter Hunt, entitled “Circuits for Efficient Detection of Vector Signaling Codes for Chip-to-Chip Communications using Sums of Differences”",
"(herein called “Ulrich I”)."
] |
FIELD OF THE INVENTION
[0001] The invention relates to a process for conversion of a heavy hydrocarbon feed, having high flexibility regarding the production of gasoline and propylene. More precisely, the process of the present invention can co-produce gasoline in a minimum yield and propylene with a yield which may reach 10% of the weight of the feed.
[0002] The minimum yield of gasoline depends on the starting feed, but routine feeds such as vacuum distillates or atmospheric residues, this minimum yield is more than 40%, and preferably more than 45% by weight with respect to the entering feed.
[0003] Demand for propylene has been increasing strongly for many years. The principal source of propylene production is the steam cracking of naphtha. Since the increase in propylene yield from the steam cracking process is limited, refiners have been prompted to produce more and more propylene using the catalytic cracking process known as FCC, fluid catalytic cracking.
[0004] The FCC process can convert heavy hydrocarbon feeds the initial boiling point of which is generally more than 340° C. to lighter hydrocarbon fractions, in particular a gasoline cut, by cracking molecules of the heavy feed in the presence of an acid catalyst.
[0005] FCC also produces liquefied petroleum gas (LPG) in large quantities with high olefins contents.
[0006] Carrying out catalytic cracking orientated towards the production of propylene necessitates either using more severe operating conditions (increase the temperature at the FCC reactor outlet and moving the catalyst faster) or using specific additives for the cracking catalyst or a combination of those two principal means.
[0007] In general, the propylene yield is obtained to the detriment of the gasoline yield and is associated with relatively severe operating conditions.
[0008] In the process of the present invention, the gasoline yield is maintained at a minimum value which clearly depends on the nature of the feed and the catalyst used, even when the operating conditions are determined with a view to maximizing the propylene production.
[0009] When propylene production is not the intention, the process can then be allowed to maximize gasoline production.
[0010] The process of the present invention can thus generally be presented as a process for the co-production of propylene and gasoline with a minimum gasoline yield.
[0011] The process employs, in succession, the reactions of catalytic cracking and oligomerization of olefins from the C3/C4 cut, or from the C4 cut, or from the C4/C5 cut, the term Cn denoting a cut of hydrocarbons containing n carbon atoms. This process produces gasoline with a minimum yield which is generally more than 40% by weight with respect to the entering feed and propylene in a yield which can be adjusted within a wide range, which for certain feeds can be up to 10% by weight.
[0012] The present invention is compatible with all catalytic cracking reactor technologies, whether using riser or dropper technology.
EXAMINATION OF THE PRIOR ART
[0013] Patent FR-2 837 213 describes a process for conversion of a heavy feed which comprises a step for catalytic cracking, selective hydrogenation and oligomerization of olefins containing 4 and/or 5 carbon atoms derived from catalytic cracking. The heavy feed and the oligomers are cracked together or separately with the same catalyst. The cracking effluents are separated in a common fractionation zone. A portion of the C4 or C4/C5 cut obtained after fractionation is oligomerized. When the C4 cut is oligomerized then cracked as a secondary feed, this process increases the propylene yield while retaining the gasoline yield. In common with the cited patent, the process of the present invention can increase the propylene yield while slightly increasing the gasoline yield, but it offers in addition the possibility of substantially increasing the gasoline yield and the capacity of the unit if the propylene production is no longer desired, all using the same facility and without changing the catalyst.
[0014] Patent FR-2 837 100 describes a process for producing propylene and gasoline comprising at least one step for oligomerization and a step for catalytic cracking of the oligomers formed. The oligomers formed from olefins containing 4 and/or 5 carbon atoms are cracked in a catalytic cracking unit to form large quantities of propylene. The feed for the process of the cited patent is thus a “light” hydrocarbon feed with a boiling point of less than 340° C. In contrast to the process described in patent FR-2 837 199, the process of the present invention concerns the conversion of a heavy feed with a boiling point of more than 340° C. in order to obtain a lot of gasoline and more or less propylene.
BRIEF DESCRIPTION OF THE FIGURES
[0015] FIG. 1 shows a flow chart for the process of the invention in its “maxi propylene” regime;
[0016] FIG. 2 shows a flow chart for the process of the invention in its “maxi gasoline” regime.
BRIEF DESCRIPTION OF THE INVENTION
[0017] The invention concerns a process for conversion of a hydrocarbon feed termed a heavy feed, i.e. constituted by hydrocarbons with a boiling point of more than approximately 340° C., with a view to the co-production of propylene and gasoline with a minimum yield.
[0018] The process of the invention comprises at least two reaction steps, a first catalytic cracking step and a second step for oligomerization of C3 and C4 olefins, or C4 olefins or C4 and C5 olefins, derived from catalytic cracking.
[0019] A third reaction step for selective olefin hydrogenation may in certain cases be necessary before oligomerization.
[0020] The process of the invention means that two types of production corresponding to two distinct regimes can be carried out:
a regime termed “maxi propylene” corresponding to a maximum production of propylene while maintaining a minimum or even slightly increased gasoline yield with respect to the potential yield of the catalytic cracking unit alone; or a regime termed “maxi gasoline”, corresponding to a maximum production of gasoline without the production of propylene.
[0023] One of the advantages of the invention is to be able to swing over time from one to the other of the two regimes defined above. It is also possible to operate the unit in any intermediate mode between the “maxi propylene” and “maxi gasoline” regimes.
[0024] This swing is very simple to carry out as it essentially consists of modifying the feed entering the oligomerization unit without substantially modifying the operating conditions of the catalytic cracking unit and the oligomerization unit and clearly without modifying the catalysts used.
In “Maxi Propylene” Mode
[0000]
the heavy feed is cracked in a fluidized bed catalytic cracking reactor in the presence of a cracking catalyst;
a second relatively light feed is cracked with the same cracking catalyst, separately or as a mixture with the heavy feed. This second feed comprises olefins containing at least 8 carbon atoms which have been produced by oligomerization of olefins containing 4 (or 4 and 5) carbon atoms derived from catalytic cracking. We shall henceforth refer to the C4 olefinic cut or the C4/C5 olefinic cut;
the cracking effluents from the two feeds are sent to a common fractionation zone and the catalyst used for cracking of the two feeds is regenerated in a common regeneration zone;
the C4 (or C4/C5) olefinic cut from catalytic cracking is sent to an oligomerization unit. Selective hydrogenation of the C4 (or C4/C5) cut before the oligomerization unit may be necessary, as well as a prior treatment, to remove impurities such as nitrogen-containing and sulphur-containing compounds. A portion of the oligomers formed are sent for catalytic cracking to produce propylene as they are good propylene precursors. The remainder of the non-recycled oligomers is mixed with the gasoline cut produced by the catalytic cracking.
In “maxi gasoline mode”
the heavy feed is cracked in the catalytic cracking reactor in the presence of the same cracking catalyst as that used in the “maxi propylene” mode. Since there is no other cracked feed, a quantity of heavy feed which is greater than that of the maxi propylene mode may be converted;
the C3/C4 cut from catalytic cracking is sent to an oligomerization unit. Selective hydrogenation of the C3/C4 cut upstream of the oligomerization unit may be necessary;
the C6+ oligomers formed are separated into a gasoline cut which is mixed with the gasoline cut produced by catalytic cracking and a heavier cut which may be incorporated into the gas oil pool.
[0032] As can be seen in the flowcharts for the process ( FIG. 1 for the maxi propylene regime, FIG. 2 for the maxi gasoline regime), swinging from one regime to the other is very simple. As an example, in order to pass from the “maxi propylene” regime to the “maxi gasoline” regime, it suffices to send the C3+C4 olefinic cut (and not just the C4 cut or the C4+C5 cut) to the oligomerization unit, no longer recycling the oligomers formed to the catalytic cracking unit.
[0033] More precisely, the process for co-production of gasoline and propylene from a hydrocarbon feed with an initial boiling point of more than 340° C. of the invention uses a catalytic cracking unit followed by an oligomerization unit which can function in accordance with two regimes termed “maxi propylene” (regime 1 ) and “maxi gasoline” (regime 2 ) in which:
for the “maxi propylene” regime, the feed for the oligomerization unit is constituted by the C4 cut or the C4/C5 olefinic cut derived from catalytic cracking and the effluents from the oligomerization unit are separated into a C8+ oligomer cut which is recycled at least in part to the inlet to the catalytic cracking unit, the gasoline cut from the process being constituted by the gasoline cut produced in the catalytic cracking unit and the oligomer cut derived from the oligomerization unit which is not recycled for catalytic cracking; for the “maxi gasoline” regime, the feed for the oligomerization unit is constitute by the C3/C4 olefinic cut derived from catalytic cracking, and the effluents from the oligomerization unit are separated into a C6+ oligomer cut which is added to the gasoline cut derived from catalytic cracking to constitute the gasoline produced by the process;
the propylene being obtained in the two regimes from FCC effluents following separation in one or more distillation columns.
[0036] As will be defined in the next paragraph, the catalytic cracking unit may be broken down into several modalities with a single reactor processing the heavy feed and the light feed or two reactors, one processing the heavy feed and the other processing the light feed. Further, each reactor may function in riser or dropper mode.
DETAILED DESCRIPTION OF THE INVENTION
[0037] According to the invention, the overall feed to be cracked contains more than 50% by weight of hydrocarbons with a boiling point of more than 340° C. In general, the feed is constituted by a vacuum distillate or possibly an atmospheric residue. The overall cracked feed may contain up to 100% by weight of hydrocarbons with a boiling point of more than 340° C. for the “maxi gasoline” mode. For the “maxi propylene” mode, the feed usually contains more than 60% by weight, and more usually more than 70%, for example between 70% and 95% by weight of hydrocarbons with a boiling point of more than 340° C.
[0038] The secondary feed for catalytic cracking required in the “maxi propylene” mode generally contains 2% to 40% by weight, more usually 4% to 30% by weight and more preferably 6% to 25% by weight, of a cut which is rich in olefins essentially constituted by olefins containing 8 carbon atoms which have been produced by oligomerizing olefins containing 4 (or 4 and 5) carbon atoms. This oligomer cut may also contain non-negligible quantities of paraffins.
[0039] The secondary feed may also comprise other oligomers essentially formed from C2 to C10 olefins.
[0040] In accordance with the invention, the cracking catalyst is the same for the “maxi propylene” and for the “maxi gasoline” mode. It is a catalyst constituted by an ultra stable Y type zeolite dispersed in an alumina, silica or silica-alumina matrix to which an additive based on ZSM-5 zeolite is added, the total quantity of ZSM-5 crystals in the cracking unit being less than 10% by weight.
[0041] Thus, the invention can be defined as a process for the co-production of gasoline and propylene from a hydrocarbon feed with an initial boiling point of more than or equal to 340° C., said process using a catalytic cracking unit followed by an oligomerization unit which can function in accordance with two regimes termed “maxi propylene” (regime 1 ) and “maxi gasoline” (regime 2 ) in which:
for the “maxi propylene” regime, the feed for the oligomerization unit is constituted by a C4 cut or a C4/C5 olefinic cut derived from catalytic cracking and the effluents from the oligomerization unit are separated into a C8+ oligomer cut which is recycled at least in part to the inlet to the catalytic cracking unit, the gasoline cut from the process being constituted by the gasoline cut produced in the catalytic cracking unit and the oligomer cut derived from the oligomerization unit which is not recycled for catalytic cracking; for the “maxi gasoline” regime, the feed for the oligomerization unit is constitute by the olefinic C3/C4 cut derived from catalytic cracking, and the effluents from the oligomerization unit are separated into a C6+ oligomer cut which is added to the gasoline cut derived from catalytic cracking to constitute the gasoline produced by the process;
the propylene being obtained in the two regimes from FCC effluents after separation in one or more distillation columns.
[0044] The catalytic cracking unit may comprise a single reactor processing both the heavy feed and the light feed or two distinct reactors, one processing the heavy feed, the other processing the light feed. Further, each of the reactors may be in riser or dropper mode. Usually, the two reactors will have the same mode of flow.
A) In the “Maxi Propylene” Regime
[0045] 1) When the catalytic cracking is carried out in a single reactor in riser mode, the reactor outlet temperature (ROT) is in the range 510° C. to 580° C., preferably in the range 540° C. to 590° C., and the C/O ratio is in the range 8 to 20;
2) When the reactor is in dropper mode, the reactor outlet temperature (ROT) is in the range 550° C. to 590° C. and the C/O ratio is in the range 15 to 50;
3) When the catalytic cracking is carried out in two distinct FCC reactors in dropper mode, the first FCC reactor carrying out cracking of the heavy feed operates at a reactor outlet temperature (ROT 1 ) in the range 510° C. to 580° C., preferably in the range 530° C. to 560° C., and with a C/O ratio in the range 5 to 10, and the second FCC reactor carrying out cracking of C8+ reactors from the oligomerization unit (termed the light feed) operates at a reactor outlet temperature (ROT 2 ) in the range 550° C. to 650° C., preferably in the range 570° C. to 620° C., with a C/O ratio in the range 8 to 25.
4) When the catalytic cracking is carried out in two distinct FCC reactors in dropper mode, the first FCC reactor carrying out cracking of the heavy feed operates at a reactor outlet temperature (ROT 1 ) in the range 550° C. to 700° C. with a C/O ratio in the range 15 to 50, and the second FCC reactor operating cracking of the C8+ oligomers from the oligomerization unit (termed the light feed) operates at a reactor outlet temperature (ROT 2 ) in the range 570° C. to 700° C., with a C/O ratio in the range 15 to 50.
B) In the “Maxi Gasoline” Regime
[0046] 1) When the catalytic cracking is carried out in one or two reactors operating in dropper mode, the reactor outlet temperature (ROT) of each cracking reactor is in the range 500° C. to 580° C., preferably in the range 520° C. to 550° C., and the C/O ratio is in the range 5 to 10.
2) When the catalytic cracking is carried out in one or two reactors operating in dropper mode, the reactor outlet temperature (ROT) of each cracking reactor is in the range 530° C. to 650° C., and the C/O ratio is in the range 15 to 25.
[0047] The streams of used catalyst derived from the two FCC reactors are separated from the cracking effluents using any gas-solid separation system which is known to the skilled person and regenerated in a common reference zone.
[0048] The effluent from the catalytic cracking reactor (or the two effluents if there are two FCC reactors) is sent to a fractionation zone to produce a plurality of cuts including a gasoline cut and a cut containing olefins:
containing 4 (or 4 and 5) carbon atoms for the “maxi propylene” mode; containing 3 and 4 carbon atoms for the “maxi gasoline” mode.
[0051] This cut containing 3 and 4 (denoted C3/C4) or 4 (denoted C4) or 4 and 5 (denoted C4/C5) carbon atoms is sent for oligomerization. It is generally preferable for this cut to undergo selective hydrogenation to reduce the diolefinic compounds and/or acetylenic compounds which may be present in order to increase the oligomerization cycle time. The separation unit constituted by one or more distillation columns is adjusted to allow extraction of the C4 or C4/C5 cut or the C3/C4 cut.
[0052] In “maxi gasoline” mode, the major portion or all of the oligomers produced is added to the gasoline cut obtained by fractionation of the catalytic cracking effluent. The gasoline yield, with respect to the quantity of hydrocarbons with a boiling point of more than 340° C., is thus generally in the range 35% to 65% by weight, usually in the range 50% to 60% by weight. The propylene yield with respect to the quantity of hydrocarbons with a boiling point of more than 340° C. is then generally less than 1% by weight and this propylene is in general not specifically recovered.
[0053] In “maxi propylene” mode, a portion, i.e. at least 30%, and preferably all of the oligomers produced, is recycled to catalytic cracking. The gasoline yield, with respect to the quantity of hydrocarbons with a boiling point of more than 340° C., is then generally in the range 35% to 55% by weight, usually in the range 40% to 50% by weight. The propylene yield with respect to the quantity of hydrocarbons with a boiling point of more than 340° C. is then generally in the range 4% to 20% by weight, usually in the range 5% to 15% and more usually in the range 7% to 12% by weight.
[0054] The particular conditions for the various steps of the process of the invention are described below in more detail.
1) Catalytic Cracking (FCC):
[0055] The catalyst for the FCC reactor is typically used in the foil of a fine powder with a mean particle diameter which is generally in the range 40 to 140 micrometres, usually in the range 50 to 120 micrometres.
[0056] The catalyst for catalytic cracking contains at least one Y type zeolite dispersed in an appropriate matrix such as alumina, silica or silica-alumina.
[0057] The catalyst may also comprise at least one zeolite with form selectivity with one of the following structure types: MEL (for example ZSM-11), MFI (for example ZSM-5), NES, EUO, FER, CHA (for example SAPO-34), MFS, MWW, or it may also be one of the following zeolites: NU-85, NU-86, NU-88 and IM-5, which also has form selectivity. The advantage of these zeolites with form selectivity is that better propylene/isobutene selectivity is obtained, i.e. with a propylene/isobutene ratio which is higher in the cracking effluents.
[0058] The proportion of zeolite with form selectivity with respect to the total quantity of zeolite may vary as a function of the feeds used and of the desired product structure. Frequently, 2% to 60% is used, preferably 3% to 40% and in particular 3% to 30% by weight of zeolite(s) with form selectivity.
[0059] The zeolite or zeolites may be dispersed in a silica, alumina or silica-alumina based matrix, the proportion of zeolite (all zeolites together) with respect to the weight of catalyst usually being in the range 3% to 80% by weight, preferably in the range 4% to 50% by weight, for example in the range 5% to 25% by weight. In the case in which several zeolites are used, they may be incorporated into a single matrix or into a plurality of different matrices. The total amount of zeolite with form selectivity is less than 10% by weight.
[0060] The catalyst used in the catalytic cracking reactor may be constituted by an ultra stable Y type zeolite dispersed in an alumina, silica or silica-alumina matrix to which an additive based on ZSM-5 zeolite is added, the total quantity of ZSM-5 crystals being less than 10% by weight.
[0061] The unit for separating the catalytic cracking reactor effluents (FCC) generally comprises a primary separation of the FCC effluents, a section for compression and fractionation of gases as well as distillations for fractionation of the various liquid cuts.
[0062] This type of fractionation unit is well known to the skilled person and depends on the intended end result. For the “maxi propylene” regime, the C4 cut or the C4/C5 cut is separated from the effluents to send it for oligomerization, and if necessary for selective hydrogenation before oligomerization.
[0063] In the “maxi gasoline” regime, the C3/C4 cut is separated from the effluents to send it for oligomerization, and if necessary for selective hydrogenation before oligomerization.
[0064] The olefinic cuts from catalytic cracking which are sent for oligomerization may be mixed with olefin-rich cuts imported from other units such as C3/C4 cuts or C4 cuts deriving from a cokefaction unit, steam cracking unit, methanol-olefin conversion unit, etc.
[0065] For the C4 cut, isobutene may be extracted, for example by etherification of isobutene by an alcohol, then by distillation, to prevent or limit the presence of isobutene in the oligomerization step, this compound tending to form isomers which can re-crack to isobutene in the FCC, which tends to result in accumulation of this compound if a sufficient isobutene purge is not carried out.
[0066] After extracting the isobutene, it is also possible to carry out extractive distillation, for example with a solvent which may be N-methyl pyrrolidone (NMP) or dimethylsulphoxide (DMSO) or an isomer thereof, to extract the unsaturated fraction from the paraffins in the feed which are then mixed with the solvent. This means that a mixture of butenes (or even butenes/pentenes) or propylene/butenes freed of C4 (or even C4/C5) or C3/C4 paraffins can be recycled to the selective hydrogenation or oligomerization.
2) Selective Hydrogenation (Optional)
[0067] The C4 or C4/C5 cut or the C3/C4 cut of the FCC effluents contains a small quantity of dienes (diolefins) and acetylenes which increase coking of the oligomerization catalyst and thus reduce the cycle time of the oligomerization reactor. Selective hydrogenation of dienes and acetylenes to mono-olefins is thus preferable in the process of the invention, although it is not vital.
[0068] The principal aim of this step is to transform the diolefins (or dienes) into mono-olefins. The mono-olefins are the source of the oligomers produced in oligomerization step 3. Another aim of this step is to eliminate traces of acetylenic hydrocarbons present in these cuts since they are unwanted compounds as regards oligomerization. The acetylenic compounds are also transformed into mono-olefins. The residual quantity of diolefins+acetylenics of the selective hydrogenation effluent is typically less than approximately 1000 ppm by weight, preferably less than 100 ppm by weight, and more preferably less than 20 ppm by weight.
[0069] In general, this selective hydrogenation step is carried out using a catalyst comprising at least one metal selected from the group formed by nickel, palladium and platinum, deposited on a support comprising alumina, silica or silica-alumina.
[0070] The quantity of palladium on the support may typically be 0.01% to 5% by weight, preferably 0.05% to 1% by weight.
[0071] The operating temperature for the selective hydrogenation is generally in the range 0° C. to 200° C., the pressure typically is in the range 0.1 to 5 MPa, usually in the range 0.5 to 5 MPa, the hourly space velocity is typically in the range 0.5 to 20 m 3 per hour per m 3 of catalyst, preferably in the range 0.5 to 5 m 3 per hour per m 3 of catalyst, and the H 2 /(acetylenic+diolefinic compounds) molar ratio is generally in the range 0.5 to 5, preferably in the range 1 to 3.
[0072] In order to carry out selective hydrogenation, one or more fixed bed reactors is used, in downflow co-current mode for the feed to be processed and the hydrogen (or a gas containing a substantial molar fraction of hydrogen, for example at least 50%), or in downflow mode for the feed to be processed and upflow mode for the hydrogen (or hydrogen-rich gas).
[0073] When the C5 cut is sent for oligomerization, it is possible to selectively hydrogenate this cut in a unit which is separate from the unit for hydrogenation of the C3 and C4 cuts, such as in a selective gasoline hydrogenation unit, for example.
3) Oligomerization
[0074] The aim of this step is to oligomerize C4 or C4/C5 olefins (“maxi propylene” regime) or C3/C4 olefins (“maxi gasoline” regime) to obtain a mixture of hydrocarbons containing mono-olefins with a number of carbon atoms equal to eight or more. Typically, starting from C4 olefins, oligomers are obtained which mainly contain 30 or fewer carbon atoms, primarily in the range 8 to 20 carbon atoms.
[0075] Oligomerization is distinguished from polymerization by adding a limited number of molecules, the number of added molecules in the context of the invention being in the range 2 to 10, limits included, and generally in the range 2 to 5, in particular in the range 2 to 4.
[0076] The oligomers may, however, include traces of olefins which have been oligomerized with a number of molecules exceeding 10. Usually, these traces represent less than 5% by weight with respect to the oligomers fowled.
[0077] Oligomerization may be carried out in one or more steps, with one or more reactors and one or more catalysts. The following description of the catalyst and the operating conditions may be applied to any one of the steps and/or any one of the reactors:
in “maxi propylene” regime, the oligomerization catalyst used is preferably a catalyst based on silica-alumina. The temperature is in the range 100° C. to 200° C., and preferably in the range 140° C. to 160° C. The pressure is in the range 0.5 to 10 MPa. In “maxi gasoline” regime, the oligomerization catalyst used is preferably a catalyst based on silica-alumina. The operating temperature is in the range 100° C. to 200° C., preferably in the range 140° C. to 160° C. The operating pressure is in the range 2 to 10 MPa (1 MPa=10 6 pascal).
[0080] The invention will now be explained in more detail with the aid of the description of FIGS. 1 and 2 .
[0081] FIG. 1 shows the facility for carrying out the process of the invention in the “maxi propylene” operating regime.
[0082] The vacuum distillate or atmospheric residue feed is introduced via line 1 .
[0083] The catalytic cracking reactor (R 1 ) is supplied via two separate lines 1 and 9 .
[0084] The effluents from the catalytic cracking (R 1 ) are evacuated via line 2 and introduced into a separation zone S 1 .
[0085] The separation zone S 1 typically comprises a gas compressor and distillation/absorption means.
[0086] The C3+C4 cut of the effluents from the catalytic cracking reactor (R 1 ) is sent to the separation zone S 2 via line 4 . The gasoline corresponding to a C5-220° C. cut is evacuated via line 15 , and the other FCC effluents are evacuated via line 3 .
[0087] The separation zone S 2 typically comprises distillation means. The C3 cut containing mainly propylene is evacuated via line 5 . The highly olefinic C4 cut is sent to the oligomerization reactor R 2 via line 6 .
[0088] The oligomerization effluents are extracted via line 7 and introduced into a separation zone S 3 . The separation zone S 3 typically comprises distillation of the oligomerization effluents to recover the heavier oligomers, and the unreacted C4 cut. The C4 cut is mainly constituted by paraffinic compounds and a minority of untransformed olefinic compounds. This C4 cut is evacuated via line 8 .
[0089] The C8+ oligomers are partially and preferably completely introduced into the catalytic cracking reactor R 1 via line 9 , the line 14 corresponding to oligomers which are not recycled to R 1 . In the case in which the oligomers are not all sent for catalytic cracking, the major portion of the remaining oligomers are mixed with the gasoline from catalytic cracking. Cracking the oligomers in R 1 means that the propylene yield of the facility can be increased.
[0090] FIG. 2 shows the facility for carrying out the process of the invention in “maxi gasoline” regime.
[0091] The catalytic cracking reactor R 1 is supplied with vacuum distillate or atmospheric residue via line 1 .
[0092] The C3+C4 cut from the FCC effluents is sent to the oligomerization reactor R 2 via line 10 .
[0093] The C3+C4 cut which has not reacted in R 2 is sent to the separation zone S 2 via line 12 . The C4 cut, separated from the C3 cut in S 2 , is evacuated via line 13 .
[0094] The C6+ oligomers formed are not recycled and form a gasoline cut (line 11 ) which joins up with the gasoline cut from the catalytic cracking reactor (line 15 ). The gasoline produced by the process is thus constituted by a combination of effluents from lines 15 and 11 .
EXAMPLES
[0095] Three examples will now be described to illustrate the improved flexibility of the process over prior art processes.
Example 1
Prior Art
[0096] An atmospheric residue feed with the principal characteristics given below was processed in a FCC type catalytic cracking unit operating in two regimes (“maxi gasoline” and “maxi propylene”):
[0000]
Density
0.93
Viscosity at 50° C. (cSt)
84
Conradson carbon
4.36
Hydrogen (wt %)
12.3
TBP 10% (° C.)
387
TBP 90% (° C.)
723
[0097] The catalyst had the following characteristics:
catalyst: Y zeolite dispersed in a matrix based on silica-alumina; mean catalyst diameter: 70 micrometres; density of grain: 1250 kg/m 3 .
[0101] The pressure in the reaction zone was equal to 0.2 MPa and the operating conditions for the “maxi propylene” and “maxi gasoline” regimes were as follows:
[0000]
Mode
“Maxi propylene”
“Maxi gasoline”
Reactor outlet
550
528
temperature (° C.)
C/O ratio (by weight)
7.5
7.1
[0102] The yields of propylene, C4 cut and gasoline with respect to the feed were as follows for the regimes:
[0000]
Yield (% by weight of
fresh feed)
“Maxi propylene”
“Maxi gasoline”
Propylene
7.2
4.8
C4 cut
13.7
9.8
Gasoline (C5-220° C.)
44.1
47.1
Example 2
In Accordance with the Invention, Illustrated in FIG. 1
[0103] The atmospheric residue processed in Example 1 was used in the process of the invention in “maxi propylene” mode under the atmospheric residue cracking conditions of Example 1 for “maxi propylene” mode (C/O=7.5 and 550° C. at the reactor outlet).
[0104] The C4 cut of the catalytic cracking effluent was separated in the separation zone S 1 then S 2 , then introduced into the oligomerization reactor R 2 which operated under the following conditions:
pressure: 6.0 MPa; temperature: 140-160° C.; space velocity: 0.5 to 1
[0108] The oligomerization catalyst was amorphous silica-alumina.
[0109] Approximately 83% by weight of C4 olefins were principally oligomerized to C8 olefins.
[0110] The oligomers, separated from the unreacted oligomers and C4 paraffins in the separation zone S 3 , were completely recycled to the catalytic cracking reactor R 1 .
[0111] Cracking of these oligomers could increase the propylene yield and the non-cracked oligomers increased the overall gasoline yield.
[0112] The yields of propylene, C4 cut and gasoline under the “maxi propylene” regime with respect to the atmospheric residue feed were as follows:
[0000]
Yield (% by weight of
Invention, in accordance with
fresh feed)
FIG. 1
Propylene
9.3
C4 cut
5.9
Gasoline (C5-220° C.)
49.0
[0113] Thus, compared with the “maxi propylene” regime of the prior art, there was an increase of 2 points (9.3−7.2) for the propylene and at the same time 5 points (49−44.1) for the gasoline.
Example 3
In Accordance with the Invention, Illustrated in FIG. 2
[0114] Again, the atmospheric residue processed in Example 1 was used in the process of the invention in “maxi gasoline” mode under the atmospheric residue cracking operating conditions of Example 1 for “maxi gasoline” mode (C/O=7.1 and 528° C. at the reactor outlet).
[0115] The C3+C4 cut separated in the separation zone S 1 was introduced into the oligomerization reactor R 2 which operated under the following conditions:
pressure: 6.6 MPa;
[0117] temperature: 130-160° C.;
space velocity: 0.5 to 1.
[0119] Again, the oligomerization catalyst was amorphous silica-alumina.
[0120] Approximately 87% by weight of C3+C4 olefins were oligomerized to C8, C9 and C12 olefins.
[0121] The oligomers, separated from the unreacted oligomers and paraffins in the separation zone S 3 , were added to gasoline from cracking of atmospheric residue and in a very small proportion to the gas oil pool.
[0122] The yields of propylene, C4 cut and gasoline in “maxi gasoline” regime (illustrated in FIG. 2 ) with respect to the atmospheric residue feed were as follows:
[0000]
Yield (% by weight of
Invention, in accordance with
fresh feed)
FIG. 2
Propylene
0.2
C4 cut
4.2
Gasoline (C5-220° C.)
55.2
[0123] The gasoline yield was increased by 8 points (55.2−47.1) compared with the prior art “maxi gasoline” regime. | The present invention describes a process for conversion of a heavy feed, having high flexibility as regards the production of propylene and gasoline. The process uses a catalytic cracking unit followed by a unit for oligomerization of C3/C4 olefins, C4 or C4/C5 olefins depending on the selected production. The process of the invention encompasses cases in which catalytic cracking is carried out in a single reactor or in two distinct reactors, each reactor possibly functioning in riser or dropper mode.
Optionally, an olefinic cut hydrogenation unit may be placed upstream of the oligomerization unit. | Summarize the key points of the given patent document. | [
"FIELD OF THE INVENTION [0001] The invention relates to a process for conversion of a heavy hydrocarbon feed, having high flexibility regarding the production of gasoline and propylene.",
"More precisely, the process of the present invention can co-produce gasoline in a minimum yield and propylene with a yield which may reach 10% of the weight of the feed.",
"[0002] The minimum yield of gasoline depends on the starting feed, but routine feeds such as vacuum distillates or atmospheric residues, this minimum yield is more than 40%, and preferably more than 45% by weight with respect to the entering feed.",
"[0003] Demand for propylene has been increasing strongly for many years.",
"The principal source of propylene production is the steam cracking of naphtha.",
"Since the increase in propylene yield from the steam cracking process is limited, refiners have been prompted to produce more and more propylene using the catalytic cracking process known as FCC, fluid catalytic cracking.",
"[0004] The FCC process can convert heavy hydrocarbon feeds the initial boiling point of which is generally more than 340° C. to lighter hydrocarbon fractions, in particular a gasoline cut, by cracking molecules of the heavy feed in the presence of an acid catalyst.",
"[0005] FCC also produces liquefied petroleum gas (LPG) in large quantities with high olefins contents.",
"[0006] Carrying out catalytic cracking orientated towards the production of propylene necessitates either using more severe operating conditions (increase the temperature at the FCC reactor outlet and moving the catalyst faster) or using specific additives for the cracking catalyst or a combination of those two principal means.",
"[0007] In general, the propylene yield is obtained to the detriment of the gasoline yield and is associated with relatively severe operating conditions.",
"[0008] In the process of the present invention, the gasoline yield is maintained at a minimum value which clearly depends on the nature of the feed and the catalyst used, even when the operating conditions are determined with a view to maximizing the propylene production.",
"[0009] When propylene production is not the intention, the process can then be allowed to maximize gasoline production.",
"[0010] The process of the present invention can thus generally be presented as a process for the co-production of propylene and gasoline with a minimum gasoline yield.",
"[0011] The process employs, in succession, the reactions of catalytic cracking and oligomerization of olefins from the C3/C4 cut, or from the C4 cut, or from the C4/C5 cut, the term Cn denoting a cut of hydrocarbons containing n carbon atoms.",
"This process produces gasoline with a minimum yield which is generally more than 40% by weight with respect to the entering feed and propylene in a yield which can be adjusted within a wide range, which for certain feeds can be up to 10% by weight.",
"[0012] The present invention is compatible with all catalytic cracking reactor technologies, whether using riser or dropper technology.",
"EXAMINATION OF THE PRIOR ART [0013] Patent FR-2 837 213 describes a process for conversion of a heavy feed which comprises a step for catalytic cracking, selective hydrogenation and oligomerization of olefins containing 4 and/or 5 carbon atoms derived from catalytic cracking.",
"The heavy feed and the oligomers are cracked together or separately with the same catalyst.",
"The cracking effluents are separated in a common fractionation zone.",
"A portion of the C4 or C4/C5 cut obtained after fractionation is oligomerized.",
"When the C4 cut is oligomerized then cracked as a secondary feed, this process increases the propylene yield while retaining the gasoline yield.",
"In common with the cited patent, the process of the present invention can increase the propylene yield while slightly increasing the gasoline yield, but it offers in addition the possibility of substantially increasing the gasoline yield and the capacity of the unit if the propylene production is no longer desired, all using the same facility and without changing the catalyst.",
"[0014] Patent FR-2 837 100 describes a process for producing propylene and gasoline comprising at least one step for oligomerization and a step for catalytic cracking of the oligomers formed.",
"The oligomers formed from olefins containing 4 and/or 5 carbon atoms are cracked in a catalytic cracking unit to form large quantities of propylene.",
"The feed for the process of the cited patent is thus a “light”",
"hydrocarbon feed with a boiling point of less than 340° C. In contrast to the process described in patent FR-2 837 199, the process of the present invention concerns the conversion of a heavy feed with a boiling point of more than 340° C. in order to obtain a lot of gasoline and more or less propylene.",
"BRIEF DESCRIPTION OF THE FIGURES [0015] FIG. 1 shows a flow chart for the process of the invention in its “maxi propylene”",
"regime;",
"[0016] FIG. 2 shows a flow chart for the process of the invention in its “maxi gasoline”",
"regime.",
"BRIEF DESCRIPTION OF THE INVENTION [0017] The invention concerns a process for conversion of a hydrocarbon feed termed a heavy feed, i.e. constituted by hydrocarbons with a boiling point of more than approximately 340° C., with a view to the co-production of propylene and gasoline with a minimum yield.",
"[0018] The process of the invention comprises at least two reaction steps, a first catalytic cracking step and a second step for oligomerization of C3 and C4 olefins, or C4 olefins or C4 and C5 olefins, derived from catalytic cracking.",
"[0019] A third reaction step for selective olefin hydrogenation may in certain cases be necessary before oligomerization.",
"[0020] The process of the invention means that two types of production corresponding to two distinct regimes can be carried out: a regime termed “maxi propylene”",
"corresponding to a maximum production of propylene while maintaining a minimum or even slightly increased gasoline yield with respect to the potential yield of the catalytic cracking unit alone;",
"or a regime termed “maxi gasoline”, corresponding to a maximum production of gasoline without the production of propylene.",
"[0023] One of the advantages of the invention is to be able to swing over time from one to the other of the two regimes defined above.",
"It is also possible to operate the unit in any intermediate mode between the “maxi propylene”",
"and “maxi gasoline”",
"regimes.",
"[0024] This swing is very simple to carry out as it essentially consists of modifying the feed entering the oligomerization unit without substantially modifying the operating conditions of the catalytic cracking unit and the oligomerization unit and clearly without modifying the catalysts used.",
"In “Maxi Propylene”",
"Mode [0000] the heavy feed is cracked in a fluidized bed catalytic cracking reactor in the presence of a cracking catalyst;",
"a second relatively light feed is cracked with the same cracking catalyst, separately or as a mixture with the heavy feed.",
"This second feed comprises olefins containing at least 8 carbon atoms which have been produced by oligomerization of olefins containing 4 (or 4 and 5) carbon atoms derived from catalytic cracking.",
"We shall henceforth refer to the C4 olefinic cut or the C4/C5 olefinic cut;",
"the cracking effluents from the two feeds are sent to a common fractionation zone and the catalyst used for cracking of the two feeds is regenerated in a common regeneration zone;",
"the C4 (or C4/C5) olefinic cut from catalytic cracking is sent to an oligomerization unit.",
"Selective hydrogenation of the C4 (or C4/C5) cut before the oligomerization unit may be necessary, as well as a prior treatment, to remove impurities such as nitrogen-containing and sulphur-containing compounds.",
"A portion of the oligomers formed are sent for catalytic cracking to produce propylene as they are good propylene precursors.",
"The remainder of the non-recycled oligomers is mixed with the gasoline cut produced by the catalytic cracking.",
"In “maxi gasoline mode”",
"the heavy feed is cracked in the catalytic cracking reactor in the presence of the same cracking catalyst as that used in the “maxi propylene”",
"mode.",
"Since there is no other cracked feed, a quantity of heavy feed which is greater than that of the maxi propylene mode may be converted;",
"the C3/C4 cut from catalytic cracking is sent to an oligomerization unit.",
"Selective hydrogenation of the C3/C4 cut upstream of the oligomerization unit may be necessary;",
"the C6+ oligomers formed are separated into a gasoline cut which is mixed with the gasoline cut produced by catalytic cracking and a heavier cut which may be incorporated into the gas oil pool.",
"[0032] As can be seen in the flowcharts for the process ( FIG. 1 for the maxi propylene regime, FIG. 2 for the maxi gasoline regime), swinging from one regime to the other is very simple.",
"As an example, in order to pass from the “maxi propylene”",
"regime to the “maxi gasoline”",
"regime, it suffices to send the C3+C4 olefinic cut (and not just the C4 cut or the C4+C5 cut) to the oligomerization unit, no longer recycling the oligomers formed to the catalytic cracking unit.",
"[0033] More precisely, the process for co-production of gasoline and propylene from a hydrocarbon feed with an initial boiling point of more than 340° C. of the invention uses a catalytic cracking unit followed by an oligomerization unit which can function in accordance with two regimes termed “maxi propylene”",
"(regime 1 ) and “maxi gasoline”",
"(regime 2 ) in which: for the “maxi propylene”",
"regime, the feed for the oligomerization unit is constituted by the C4 cut or the C4/C5 olefinic cut derived from catalytic cracking and the effluents from the oligomerization unit are separated into a C8+ oligomer cut which is recycled at least in part to the inlet to the catalytic cracking unit, the gasoline cut from the process being constituted by the gasoline cut produced in the catalytic cracking unit and the oligomer cut derived from the oligomerization unit which is not recycled for catalytic cracking;",
"for the “maxi gasoline”",
"regime, the feed for the oligomerization unit is constitute by the C3/C4 olefinic cut derived from catalytic cracking, and the effluents from the oligomerization unit are separated into a C6+ oligomer cut which is added to the gasoline cut derived from catalytic cracking to constitute the gasoline produced by the process;",
"the propylene being obtained in the two regimes from FCC effluents following separation in one or more distillation columns.",
"[0036] As will be defined in the next paragraph, the catalytic cracking unit may be broken down into several modalities with a single reactor processing the heavy feed and the light feed or two reactors, one processing the heavy feed and the other processing the light feed.",
"Further, each reactor may function in riser or dropper mode.",
"DETAILED DESCRIPTION OF THE INVENTION [0037] According to the invention, the overall feed to be cracked contains more than 50% by weight of hydrocarbons with a boiling point of more than 340° C. In general, the feed is constituted by a vacuum distillate or possibly an atmospheric residue.",
"The overall cracked feed may contain up to 100% by weight of hydrocarbons with a boiling point of more than 340° C. for the “maxi gasoline”",
"mode.",
"For the “maxi propylene”",
"mode, the feed usually contains more than 60% by weight, and more usually more than 70%, for example between 70% and 95% by weight of hydrocarbons with a boiling point of more than 340° C. [0038] The secondary feed for catalytic cracking required in the “maxi propylene”",
"mode generally contains 2% to 40% by weight, more usually 4% to 30% by weight and more preferably 6% to 25% by weight, of a cut which is rich in olefins essentially constituted by olefins containing 8 carbon atoms which have been produced by oligomerizing olefins containing 4 (or 4 and 5) carbon atoms.",
"This oligomer cut may also contain non-negligible quantities of paraffins.",
"[0039] The secondary feed may also comprise other oligomers essentially formed from C2 to C10 olefins.",
"[0040] In accordance with the invention, the cracking catalyst is the same for the “maxi propylene”",
"and for the “maxi gasoline”",
"mode.",
"It is a catalyst constituted by an ultra stable Y type zeolite dispersed in an alumina, silica or silica-alumina matrix to which an additive based on ZSM-5 zeolite is added, the total quantity of ZSM-5 crystals in the cracking unit being less than 10% by weight.",
"[0041] Thus, the invention can be defined as a process for the co-production of gasoline and propylene from a hydrocarbon feed with an initial boiling point of more than or equal to 340° C., said process using a catalytic cracking unit followed by an oligomerization unit which can function in accordance with two regimes termed “maxi propylene”",
"(regime 1 ) and “maxi gasoline”",
"(regime 2 ) in which: for the “maxi propylene”",
"regime, the feed for the oligomerization unit is constituted by a C4 cut or a C4/C5 olefinic cut derived from catalytic cracking and the effluents from the oligomerization unit are separated into a C8+ oligomer cut which is recycled at least in part to the inlet to the catalytic cracking unit, the gasoline cut from the process being constituted by the gasoline cut produced in the catalytic cracking unit and the oligomer cut derived from the oligomerization unit which is not recycled for catalytic cracking;",
"for the “maxi gasoline”",
"regime, the feed for the oligomerization unit is constitute by the olefinic C3/C4 cut derived from catalytic cracking, and the effluents from the oligomerization unit are separated into a C6+ oligomer cut which is added to the gasoline cut derived from catalytic cracking to constitute the gasoline produced by the process;",
"the propylene being obtained in the two regimes from FCC effluents after separation in one or more distillation columns.",
"[0044] The catalytic cracking unit may comprise a single reactor processing both the heavy feed and the light feed or two distinct reactors, one processing the heavy feed, the other processing the light feed.",
"Further, each of the reactors may be in riser or dropper mode.",
"Usually, the two reactors will have the same mode of flow.",
"A) In the “Maxi Propylene”",
"Regime [0045] 1) When the catalytic cracking is carried out in a single reactor in riser mode, the reactor outlet temperature (ROT) is in the range 510° C. to 580° C., preferably in the range 540° C. to 590° C., and the C/O ratio is in the range 8 to 20;",
"2) When the reactor is in dropper mode, the reactor outlet temperature (ROT) is in the range 550° C. to 590° C. and the C/O ratio is in the range 15 to 50;",
"3) When the catalytic cracking is carried out in two distinct FCC reactors in dropper mode, the first FCC reactor carrying out cracking of the heavy feed operates at a reactor outlet temperature (ROT 1 ) in the range 510° C. to 580° C., preferably in the range 530° C. to 560° C., and with a C/O ratio in the range 5 to 10, and the second FCC reactor carrying out cracking of C8+ reactors from the oligomerization unit (termed the light feed) operates at a reactor outlet temperature (ROT 2 ) in the range 550° C. to 650° C., preferably in the range 570° C. to 620° C., with a C/O ratio in the range 8 to 25.",
"4) When the catalytic cracking is carried out in two distinct FCC reactors in dropper mode, the first FCC reactor carrying out cracking of the heavy feed operates at a reactor outlet temperature (ROT 1 ) in the range 550° C. to 700° C. with a C/O ratio in the range 15 to 50, and the second FCC reactor operating cracking of the C8+ oligomers from the oligomerization unit (termed the light feed) operates at a reactor outlet temperature (ROT 2 ) in the range 570° C. to 700° C., with a C/O ratio in the range 15 to 50.",
"B) In the “Maxi Gasoline”",
"Regime [0046] 1) When the catalytic cracking is carried out in one or two reactors operating in dropper mode, the reactor outlet temperature (ROT) of each cracking reactor is in the range 500° C. to 580° C., preferably in the range 520° C. to 550° C., and the C/O ratio is in the range 5 to 10.",
"2) When the catalytic cracking is carried out in one or two reactors operating in dropper mode, the reactor outlet temperature (ROT) of each cracking reactor is in the range 530° C. to 650° C., and the C/O ratio is in the range 15 to 25.",
"[0047] The streams of used catalyst derived from the two FCC reactors are separated from the cracking effluents using any gas-solid separation system which is known to the skilled person and regenerated in a common reference zone.",
"[0048] The effluent from the catalytic cracking reactor (or the two effluents if there are two FCC reactors) is sent to a fractionation zone to produce a plurality of cuts including a gasoline cut and a cut containing olefins: containing 4 (or 4 and 5) carbon atoms for the “maxi propylene”",
"mode;",
"containing 3 and 4 carbon atoms for the “maxi gasoline”",
"mode.",
"[0051] This cut containing 3 and 4 (denoted C3/C4) or 4 (denoted C4) or 4 and 5 (denoted C4/C5) carbon atoms is sent for oligomerization.",
"It is generally preferable for this cut to undergo selective hydrogenation to reduce the diolefinic compounds and/or acetylenic compounds which may be present in order to increase the oligomerization cycle time.",
"The separation unit constituted by one or more distillation columns is adjusted to allow extraction of the C4 or C4/C5 cut or the C3/C4 cut.",
"[0052] In “maxi gasoline”",
"mode, the major portion or all of the oligomers produced is added to the gasoline cut obtained by fractionation of the catalytic cracking effluent.",
"The gasoline yield, with respect to the quantity of hydrocarbons with a boiling point of more than 340° C., is thus generally in the range 35% to 65% by weight, usually in the range 50% to 60% by weight.",
"The propylene yield with respect to the quantity of hydrocarbons with a boiling point of more than 340° C. is then generally less than 1% by weight and this propylene is in general not specifically recovered.",
"[0053] In “maxi propylene”",
"mode, a portion, i.e. at least 30%, and preferably all of the oligomers produced, is recycled to catalytic cracking.",
"The gasoline yield, with respect to the quantity of hydrocarbons with a boiling point of more than 340° C., is then generally in the range 35% to 55% by weight, usually in the range 40% to 50% by weight.",
"The propylene yield with respect to the quantity of hydrocarbons with a boiling point of more than 340° C. is then generally in the range 4% to 20% by weight, usually in the range 5% to 15% and more usually in the range 7% to 12% by weight.",
"[0054] The particular conditions for the various steps of the process of the invention are described below in more detail.",
"1) Catalytic Cracking (FCC): [0055] The catalyst for the FCC reactor is typically used in the foil of a fine powder with a mean particle diameter which is generally in the range 40 to 140 micrometres, usually in the range 50 to 120 micrometres.",
"[0056] The catalyst for catalytic cracking contains at least one Y type zeolite dispersed in an appropriate matrix such as alumina, silica or silica-alumina.",
"[0057] The catalyst may also comprise at least one zeolite with form selectivity with one of the following structure types: MEL (for example ZSM-11), MFI (for example ZSM-5), NES, EUO, FER, CHA (for example SAPO-34), MFS, MWW, or it may also be one of the following zeolites: NU-85, NU-86, NU-88 and IM-5, which also has form selectivity.",
"The advantage of these zeolites with form selectivity is that better propylene/isobutene selectivity is obtained, i.e. with a propylene/isobutene ratio which is higher in the cracking effluents.",
"[0058] The proportion of zeolite with form selectivity with respect to the total quantity of zeolite may vary as a function of the feeds used and of the desired product structure.",
"Frequently, 2% to 60% is used, preferably 3% to 40% and in particular 3% to 30% by weight of zeolite(s) with form selectivity.",
"[0059] The zeolite or zeolites may be dispersed in a silica, alumina or silica-alumina based matrix, the proportion of zeolite (all zeolites together) with respect to the weight of catalyst usually being in the range 3% to 80% by weight, preferably in the range 4% to 50% by weight, for example in the range 5% to 25% by weight.",
"In the case in which several zeolites are used, they may be incorporated into a single matrix or into a plurality of different matrices.",
"The total amount of zeolite with form selectivity is less than 10% by weight.",
"[0060] The catalyst used in the catalytic cracking reactor may be constituted by an ultra stable Y type zeolite dispersed in an alumina, silica or silica-alumina matrix to which an additive based on ZSM-5 zeolite is added, the total quantity of ZSM-5 crystals being less than 10% by weight.",
"[0061] The unit for separating the catalytic cracking reactor effluents (FCC) generally comprises a primary separation of the FCC effluents, a section for compression and fractionation of gases as well as distillations for fractionation of the various liquid cuts.",
"[0062] This type of fractionation unit is well known to the skilled person and depends on the intended end result.",
"For the “maxi propylene”",
"regime, the C4 cut or the C4/C5 cut is separated from the effluents to send it for oligomerization, and if necessary for selective hydrogenation before oligomerization.",
"[0063] In the “maxi gasoline”",
"regime, the C3/C4 cut is separated from the effluents to send it for oligomerization, and if necessary for selective hydrogenation before oligomerization.",
"[0064] The olefinic cuts from catalytic cracking which are sent for oligomerization may be mixed with olefin-rich cuts imported from other units such as C3/C4 cuts or C4 cuts deriving from a cokefaction unit, steam cracking unit, methanol-olefin conversion unit, etc.",
"[0065] For the C4 cut, isobutene may be extracted, for example by etherification of isobutene by an alcohol, then by distillation, to prevent or limit the presence of isobutene in the oligomerization step, this compound tending to form isomers which can re-crack to isobutene in the FCC, which tends to result in accumulation of this compound if a sufficient isobutene purge is not carried out.",
"[0066] After extracting the isobutene, it is also possible to carry out extractive distillation, for example with a solvent which may be N-methyl pyrrolidone (NMP) or dimethylsulphoxide (DMSO) or an isomer thereof, to extract the unsaturated fraction from the paraffins in the feed which are then mixed with the solvent.",
"This means that a mixture of butenes (or even butenes/pentenes) or propylene/butenes freed of C4 (or even C4/C5) or C3/C4 paraffins can be recycled to the selective hydrogenation or oligomerization.",
"2) Selective Hydrogenation (Optional) [0067] The C4 or C4/C5 cut or the C3/C4 cut of the FCC effluents contains a small quantity of dienes (diolefins) and acetylenes which increase coking of the oligomerization catalyst and thus reduce the cycle time of the oligomerization reactor.",
"Selective hydrogenation of dienes and acetylenes to mono-olefins is thus preferable in the process of the invention, although it is not vital.",
"[0068] The principal aim of this step is to transform the diolefins (or dienes) into mono-olefins.",
"The mono-olefins are the source of the oligomers produced in oligomerization step 3.",
"Another aim of this step is to eliminate traces of acetylenic hydrocarbons present in these cuts since they are unwanted compounds as regards oligomerization.",
"The acetylenic compounds are also transformed into mono-olefins.",
"The residual quantity of diolefins+acetylenics of the selective hydrogenation effluent is typically less than approximately 1000 ppm by weight, preferably less than 100 ppm by weight, and more preferably less than 20 ppm by weight.",
"[0069] In general, this selective hydrogenation step is carried out using a catalyst comprising at least one metal selected from the group formed by nickel, palladium and platinum, deposited on a support comprising alumina, silica or silica-alumina.",
"[0070] The quantity of palladium on the support may typically be 0.01% to 5% by weight, preferably 0.05% to 1% by weight.",
"[0071] The operating temperature for the selective hydrogenation is generally in the range 0° C. to 200° C., the pressure typically is in the range 0.1 to 5 MPa, usually in the range 0.5 to 5 MPa, the hourly space velocity is typically in the range 0.5 to 20 m 3 per hour per m 3 of catalyst, preferably in the range 0.5 to 5 m 3 per hour per m 3 of catalyst, and the H 2 /(acetylenic+diolefinic compounds) molar ratio is generally in the range 0.5 to 5, preferably in the range 1 to 3.",
"[0072] In order to carry out selective hydrogenation, one or more fixed bed reactors is used, in downflow co-current mode for the feed to be processed and the hydrogen (or a gas containing a substantial molar fraction of hydrogen, for example at least 50%), or in downflow mode for the feed to be processed and upflow mode for the hydrogen (or hydrogen-rich gas).",
"[0073] When the C5 cut is sent for oligomerization, it is possible to selectively hydrogenate this cut in a unit which is separate from the unit for hydrogenation of the C3 and C4 cuts, such as in a selective gasoline hydrogenation unit, for example.",
"3) Oligomerization [0074] The aim of this step is to oligomerize C4 or C4/C5 olefins (“maxi propylene”",
"regime) or C3/C4 olefins (“maxi gasoline”",
"regime) to obtain a mixture of hydrocarbons containing mono-olefins with a number of carbon atoms equal to eight or more.",
"Typically, starting from C4 olefins, oligomers are obtained which mainly contain 30 or fewer carbon atoms, primarily in the range 8 to 20 carbon atoms.",
"[0075] Oligomerization is distinguished from polymerization by adding a limited number of molecules, the number of added molecules in the context of the invention being in the range 2 to 10, limits included, and generally in the range 2 to 5, in particular in the range 2 to 4.",
"[0076] The oligomers may, however, include traces of olefins which have been oligomerized with a number of molecules exceeding 10.",
"Usually, these traces represent less than 5% by weight with respect to the oligomers fowled.",
"[0077] Oligomerization may be carried out in one or more steps, with one or more reactors and one or more catalysts.",
"The following description of the catalyst and the operating conditions may be applied to any one of the steps and/or any one of the reactors: in “maxi propylene”",
"regime, the oligomerization catalyst used is preferably a catalyst based on silica-alumina.",
"The temperature is in the range 100° C. to 200° C., and preferably in the range 140° C. to 160° C. The pressure is in the range 0.5 to 10 MPa.",
"In “maxi gasoline”",
"regime, the oligomerization catalyst used is preferably a catalyst based on silica-alumina.",
"The operating temperature is in the range 100° C. to 200° C., preferably in the range 140° C. to 160° C. The operating pressure is in the range 2 to 10 MPa (1 MPa=10 6 pascal).",
"[0080] The invention will now be explained in more detail with the aid of the description of FIGS. 1 and 2 .",
"[0081] FIG. 1 shows the facility for carrying out the process of the invention in the “maxi propylene”",
"operating regime.",
"[0082] The vacuum distillate or atmospheric residue feed is introduced via line 1 .",
"[0083] The catalytic cracking reactor (R 1 ) is supplied via two separate lines 1 and 9 .",
"[0084] The effluents from the catalytic cracking (R 1 ) are evacuated via line 2 and introduced into a separation zone S 1 .",
"[0085] The separation zone S 1 typically comprises a gas compressor and distillation/absorption means.",
"[0086] The C3+C4 cut of the effluents from the catalytic cracking reactor (R 1 ) is sent to the separation zone S 2 via line 4 .",
"The gasoline corresponding to a C5-220° C. cut is evacuated via line 15 , and the other FCC effluents are evacuated via line 3 .",
"[0087] The separation zone S 2 typically comprises distillation means.",
"The C3 cut containing mainly propylene is evacuated via line 5 .",
"The highly olefinic C4 cut is sent to the oligomerization reactor R 2 via line 6 .",
"[0088] The oligomerization effluents are extracted via line 7 and introduced into a separation zone S 3 .",
"The separation zone S 3 typically comprises distillation of the oligomerization effluents to recover the heavier oligomers, and the unreacted C4 cut.",
"The C4 cut is mainly constituted by paraffinic compounds and a minority of untransformed olefinic compounds.",
"This C4 cut is evacuated via line 8 .",
"[0089] The C8+ oligomers are partially and preferably completely introduced into the catalytic cracking reactor R 1 via line 9 , the line 14 corresponding to oligomers which are not recycled to R 1 .",
"In the case in which the oligomers are not all sent for catalytic cracking, the major portion of the remaining oligomers are mixed with the gasoline from catalytic cracking.",
"Cracking the oligomers in R 1 means that the propylene yield of the facility can be increased.",
"[0090] FIG. 2 shows the facility for carrying out the process of the invention in “maxi gasoline”",
"regime.",
"[0091] The catalytic cracking reactor R 1 is supplied with vacuum distillate or atmospheric residue via line 1 .",
"[0092] The C3+C4 cut from the FCC effluents is sent to the oligomerization reactor R 2 via line 10 .",
"[0093] The C3+C4 cut which has not reacted in R 2 is sent to the separation zone S 2 via line 12 .",
"The C4 cut, separated from the C3 cut in S 2 , is evacuated via line 13 .",
"[0094] The C6+ oligomers formed are not recycled and form a gasoline cut (line 11 ) which joins up with the gasoline cut from the catalytic cracking reactor (line 15 ).",
"The gasoline produced by the process is thus constituted by a combination of effluents from lines 15 and 11 .",
"EXAMPLES [0095] Three examples will now be described to illustrate the improved flexibility of the process over prior art processes.",
"Example 1 Prior Art [0096] An atmospheric residue feed with the principal characteristics given below was processed in a FCC type catalytic cracking unit operating in two regimes (“maxi gasoline”",
"and “maxi propylene”): [0000] Density 0.93 Viscosity at 50° C. (cSt) 84 Conradson carbon 4.36 Hydrogen (wt %) 12.3 TBP 10% (° C.) 387 TBP 90% (° C.) 723 [0097] The catalyst had the following characteristics: catalyst: Y zeolite dispersed in a matrix based on silica-alumina;",
"mean catalyst diameter: 70 micrometres;",
"density of grain: 1250 kg/m 3 .",
"[0101] The pressure in the reaction zone was equal to 0.2 MPa and the operating conditions for the “maxi propylene”",
"and “maxi gasoline”",
"regimes were as follows: [0000] Mode “Maxi propylene”",
"“Maxi gasoline”",
"Reactor outlet 550 528 temperature (° C.) C/O ratio (by weight) 7.5 7.1 [0102] The yields of propylene, C4 cut and gasoline with respect to the feed were as follows for the regimes: [0000] Yield (% by weight of fresh feed) “Maxi propylene”",
"“Maxi gasoline”",
"Propylene 7.2 4.8 C4 cut 13.7 9.8 Gasoline (C5-220° C.) 44.1 47.1 Example 2 In Accordance with the Invention, Illustrated in FIG. 1 [0103] The atmospheric residue processed in Example 1 was used in the process of the invention in “maxi propylene”",
"mode under the atmospheric residue cracking conditions of Example 1 for “maxi propylene”",
"mode (C/O=7.5 and 550° C. at the reactor outlet).",
"[0104] The C4 cut of the catalytic cracking effluent was separated in the separation zone S 1 then S 2 , then introduced into the oligomerization reactor R 2 which operated under the following conditions: pressure: 6.0 MPa;",
"temperature: 140-160° C.;",
"space velocity: 0.5 to 1 [0108] The oligomerization catalyst was amorphous silica-alumina.",
"[0109] Approximately 83% by weight of C4 olefins were principally oligomerized to C8 olefins.",
"[0110] The oligomers, separated from the unreacted oligomers and C4 paraffins in the separation zone S 3 , were completely recycled to the catalytic cracking reactor R 1 .",
"[0111] Cracking of these oligomers could increase the propylene yield and the non-cracked oligomers increased the overall gasoline yield.",
"[0112] The yields of propylene, C4 cut and gasoline under the “maxi propylene”",
"regime with respect to the atmospheric residue feed were as follows: [0000] Yield (% by weight of Invention, in accordance with fresh feed) FIG. 1 Propylene 9.3 C4 cut 5.9 Gasoline (C5-220° C.) 49.0 [0113] Thus, compared with the “maxi propylene”",
"regime of the prior art, there was an increase of 2 points (9.3−7.2) for the propylene and at the same time 5 points (49−44.1) for the gasoline.",
"Example 3 In Accordance with the Invention, Illustrated in FIG. 2 [0114] Again, the atmospheric residue processed in Example 1 was used in the process of the invention in “maxi gasoline”",
"mode under the atmospheric residue cracking operating conditions of Example 1 for “maxi gasoline”",
"mode (C/O=7.1 and 528° C. at the reactor outlet).",
"[0115] The C3+C4 cut separated in the separation zone S 1 was introduced into the oligomerization reactor R 2 which operated under the following conditions: pressure: 6.6 MPa;",
"[0117] temperature: 130-160° C.;",
"space velocity: 0.5 to 1.",
"[0119] Again, the oligomerization catalyst was amorphous silica-alumina.",
"[0120] Approximately 87% by weight of C3+C4 olefins were oligomerized to C8, C9 and C12 olefins.",
"[0121] The oligomers, separated from the unreacted oligomers and paraffins in the separation zone S 3 , were added to gasoline from cracking of atmospheric residue and in a very small proportion to the gas oil pool.",
"[0122] The yields of propylene, C4 cut and gasoline in “maxi gasoline”",
"regime (illustrated in FIG. 2 ) with respect to the atmospheric residue feed were as follows: [0000] Yield (% by weight of Invention, in accordance with fresh feed) FIG. 2 Propylene 0.2 C4 cut 4.2 Gasoline (C5-220° C.) 55.2 [0123] The gasoline yield was increased by 8 points (55.2−47.1) compared with the prior art “maxi gasoline”",
"regime."
] |
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority to and benefit of provisional patent application Serial No. 60/354,013, filed Jan. 31, 2002, the disclosure of which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
This invention relates generally to electric-actuated control valves, such as valves for controlling flow of fluids in automotive vehicle engine systems. In particular, the invention relates to improvements for increasing the useful stroke of such a valve by enhancing the force vs. stroke characteristic of the valve actuator. Examples of such valves are exhaust gas recirculation (EGR) valves and fuel cell valves.
BACKGROUND OF THE INVENTION
The actuator of certain control valves of automotive vehicle engine systems comprises a solenoid that comprises an electromagnet coil and a stator having an air gap at which magnetic flux acts on an armature. The armature motion is transmitted to a valve element to control flow through a passage of the valve. Armature motion is resisted by a return spring that acts on the armature, either directly or via the valve element, to bias the armature toward a position that causes the valve element to close the passage.
The stator air gap is defined by an upper pole piece that is disposed at an upper end of the coil and a lower pole piece at a lower end of the coil. The pole pieces have respective annular hubs that fit into an interior space bounded by the coil, approaching each other from opposite ends of the coil. The juxtaposed ends of the two hubs are spaced apart to define the air gap as a generally annular space within which the armature is centered and along which the armature can travel. Electric current in the coil creates magnetic flux that passes from one hub through a portion of the air gap to the armature, through the armature, and back across another portion of the air gap to the other hub. The flux creates an electromagnetic force on the armature, and the axial component of that force acts to displace the armature along the centerline of the solenoid against the resistance of the return spring. In order to operate the valve from closed to open, the solenoid must apply a force that is greater than the sum of the bias force being applied by the return spring and any other forces acting on the valve.
For achieving improved control, it is desirable that the valve actuator be able to deliver increasing force over an increased stroke length. However, certain constraints that are imposed on certain automotive vehicles, especially mass-produced vehicles that are subject to governmental regulation, make it impossible, impractical, and/or uneconomical simply to use a larger solenoid. Accordingly, it is believed that a valve that is capable of delivering increasing force over an increased stroke length, without accompanying increases in size and weight that would be deemed unacceptable, would be useful to automotive vehicle manufacturers in complying with constraints imposed on the vehicles that they manufacture.
SUMMARY OF THE INVENTION
The present invention relates to a valve that is capable of delivering increasing force over an increased stroke length, without accompanying increases in size and weight that would be deemed unacceptable.
One general aspect of the invention relates to an electric-actuated control valve for controlling flow of fluid in an automotive vehicle engine system. The valve comprises a valve body comprising a passage having an inlet port for receiving fluid and an outlet port for delivering fluid. A mechanism selectively positions a valve element to selectively restrict the passage. The mechanism comprises a solenoid actuator comprising a bobbin having a tubular core of non-ferromagnetic metal and ferromagnetic pole pieces at axial ends of the tubular core. An electromagnet coil comprising a length of magnetic wire is wound on the tubular core between flanges of the pole pieces. The pole pieces form portions of a magnetic circuit for magnetic flux created by electric current in the coil and comprise hubs that protrude into the tubular core and have juxtaposed ends defining an air gap within the tubular core through which the magnetic flux passes between the pole piece hubs. The mechanism further comprises an armature that is guided for motion axially of the tubular core for positioning the valve element and that comprises ferromagnetic material for conducting magnetic flux created at the air gap when electric current flows in the coil to cause an axial component of electromagnetic force to be exerted on the armature for positioning the valve element.
Another aspect relates to the solenoid actuator itself.
Still another aspect relates to a method of making the valve and the actuator.
The accompanying drawings, which are incorporated herein and constitute part of this specification, include a presently preferred embodiment of the invention, and together with a general description given above and a detailed description given below, serve to disclose principles of the invention in accordance with a best mode contemplated for carrying out the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of an engine system that comprises a valve in accordance with principles of the present invention.
FIG. 2 is a cross section view, in elevation, of an exemplary embodiment of an actuator of the valve of FIG. 1 embodying the present invention.
FIG. 3 is a graph plot for showing representative stroke length improvement that can be achieved with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows an exemplary emission control system 10 having an electric exhaust gas recirculation valve (EEGR valve) 12 associated with an internal combustion engine 14 to control the flow of exhaust gas being recirculated from an exhaust system 16 of the engine to an intake system 18 of the engine.
Valve 12 comprises a body containing a flow passage extending between a valve inlet port 20 communicated to exhaust system 16 and a valve outlet port 22 communicated to intake system 18 .
Valve 12 further comprises an electromagnetic actuator 24 , namely a solenoid, which is under control of an engine control system 26 to control the extent to which valve 12 allows exhaust gas to be recirculated through the flow passage in the valve body. In the closed position of valve 12 that blocks exhaust gas recirculation, a preloaded return spring within the valve body is resiliently biasing a valve element to close on a valve seat in the flow passage, closing the flow passage to flow of exhaust gas between ports 20 and 22 .
As engine control system 26 delivers increasing electric current to actuator 24 , a point is reached where the current is sufficiently large to create sufficient force for overcoming the spring bias. Further increases in current increasingly open the valve.
The improvement that is achieved by the present invention is accomplished through actuator 24 , detail of which appears in FIG. 2 .
Actuator 24 comprises stator structure 28 associated with an electromagnet coil 30 to form a portion of a magnetic circuit path. The stator structure comprises an upper pole piece 32 , disposed at one end of the actuator coaxial with a centerline CL, a lower pole piece 34 disposed at the opposite end of the actuator coaxial with centerline CL, and an outer cylindrical shell 36 . All three pieces 32 , 34 , 36 comprise ferromagnetic material.
Upper pole piece 32 comprises a circular end wall 40 and an annular walled hub 38 that extends interiorly from an interior face of end wall 40 . The junction of the hub and flange comprises a chamfer 42 between a radially outer surface of hub 38 and the interior face of end wall 40 . The chamfer ends at a shoulder 43 in the outer hub surface, and beyond that shoulder the outer hub surface continues axially as a circular cylindrical surface 44 . Beyond surface 44 , the outer hub surface continues as a frustoconical surface 46 , finally ending at a narrow flat end face 48 that is perpendicular to centerline CL.
The radially inner surface of hub 38 comprises a circular cylindrical counterbore 50 extending into the hub from face 48 as far as an internal shoulder 52 . The radially inner hub surface continues axially from shoulder 52 as a chamfer 54 , and then as a circular cylindrical bore 56 , finally ending via a chamfer 58 at an end face 60 that is perpendicular to centerline CL. Counterbore 50 and bore 56 thereby form a blind hole in pole piece 32 that is centered on centerline CL.
Lower pole piece 34 comprises a central hub 62 and a circular flange 64 that girdles hub 62 intermediate opposite axial ends of hub 62 . One portion of hub 62 that extends from an interior face of flange 64 comprises an annular wall. The junction of flange 64 and that annular wall comprises a chamfer 66 extending between the interior face of flange 64 and the outer surface of the hub wall. From chamfer 66 , the outer surface of the hub wall continues as a circular cylindrical surface 68 ending at an end face 70 that is perpendicular to centerline CL. The portion of hub 62 extending from the exterior face of flange 64 comprises an annular wall whose radially outer surface is a circular cylindrical surface 72 beginning at flange 64 and ending at a shoulder 73 . From shoulder 73 , the outer wall surface continues as a circular cylindrical surface 76 and ends at an end face 78 that is perpendicular to centerline CL.
Lower pole piece 34 further comprises a through-hole that forms the inner hub surface and comprises a circular cylindrical counterbore 80 extending from end face 70 and ending at an internal shoulder 82 . A circular cylindrical bore 84 extends from shoulder 82 to end face 78 .
Pole pieces 32 , 34 are assembled to a non-ferromagnetic tube 88 , one pole piece at one end of the tube, the other pole piece at the opposite end. Tube 88 has a circular cylindrical shape of uniform radial thickness. One end of tube 88 fits over hub 38 , being centered on surface 44 and axially abutting shoulder 43 . The other end of tube 88 fits over the upper end of hub 62 , being centered on surface 68 and abutting chamfer 66 .
The assembly of pole pieces 32 , 34 and tube 88 forms a bobbin on which magnet wire is wound to create coil 30 . Ends of the wire are led through a plastic overmold 86 and a clearance opening (not shown) in flange 40 where they can be attached to electric terminals in a cap of the valve actuator (also not shown). The cap terminals protrude externally from the cap material where they are bounded by a surround of cap material to form a connector adapted for mating connection with a wiring harness connector for connecting the coil to control system 26 . The plastic overmold 86 separates the wound coil wire from direct contact with end wall 40 of upper pole piece 32 , and is believed useful in damping vibrations. Although not shown in the drawing, a thin layer of insulating plastic or paper may be disposed around tube 88 and similar thin insulating sheets disposed over the interior face of end wall 40 and that of flange 64 for insulation between the coil wire and the metal parts of the stator structure.
A sleeve bearing 90 , carbon steel for example, is fit to surface 84 to provide guidance for axial travel of an armature 92 of actuator 24 . Such an insert may not always be needed, and replaced by a sleeve of thin non-magnetic material. Armature 92 is guided only on lower pole piece 34 and not the upper pole piece.
Armature 92 comprises ferromagnetic material having a circular cylindrical outer surface 94 guided by the inner surface of bearing 90 . The axial length of the armature overlaps the hubs of both pole pieces. At its lower end armature 92 comprises a valve actuating stem 96 that protrudes from lower pole piece 34 .
An air gap is present between confronting ends of hubs 38 and 62 within space bounded by coil 30 . Armature 92 is disposed in the air gap between juxtaposed ends of the pole piece hubs. When coil 30 is energized by electric current, magnetic flux passes from one hub across one portion of the air gap, through that portion of the armature disposed at the air gap, through another portion of the air gap, and to the other hub. Exterior to coil 30 , the magnetic circuit is completed from one pole piece to the other through shell 36 . Flanges 40 and 64 have matching circular edges, and shell 36 is fit to those edges.
The end of armature 92 disposed at the air gap has a shape that is believed beneficial in concentrating flux without saturation to improve the force vs. travel characteristic of the actuator. A frustoconical counterbore 95 is present in the end face of the armature, creating a raised annular rim 97 that bridges much of the distance between the confronting ends of the hubs of the respective pole pieces. Rim 97 is the portion of the armature through which the magnetic flux is conducted between the pole pieces at the air gap and comprises a circular radially outer surface and a frostoconical tapered radially inner surface. Rim 97 has a widening taper in the direction from the tapered wall of hub 38 toward hub 62 of pole piece 34 .
In the closed position of valve 10 , the preloaded return spring (not shown) is resiliently biasing the valve element to close the flow passage between ports 20 and 22 . That spring forms an element of the internal valve mechanism, functioning via the valve element to resiliently bias armature 92 to an initial position along centerline CL when no current flows in coil 30 .
As electric current begins to increasingly flow through coil 30 , the magnetic circuit exerts increasing electromagnetic force urging armature 92 in the downward direction as viewed in FIG. 1 . Once the force is large enough to overcome the bias of the preload force of the return spring, armature 92 begins to move downward, similarly moving the valve element and opening valve 10 to allow flow between the two ports. The position to which the armature is displaced, and hence the extent to which the valve is allowed to open, is controlled by the electric current in coil 30 . The actual control strategy for the valve is determined as part of the overall engine control strategy embodied in engine control system 26 .
Solenoid 24 , as described above, endows armature 92 with a longer useful stroke in comparison to certain other valves, as shown by Figure.
FIG. 3 is a graph plot showing armature force as a function of armature displacement for two different valves. The graph plot 100 is for valve 12 while the graph plot 102 is for a similar valve that has a solenoid different from solenoid 24 of valve 12 . It is evident that for a given amount of current in the respective coils, valve 12 delivers force that is not only larger, but that is delivered over a larger range of armature displacements. Both plots are characterized by the presence of hysteresis. For the example given, the useful stroke length has been almost doubled, with only about a 12% increase in volume of the actuator.
It is believed that the improvement provided by the invention arises because the coil is wound directly on tube 88 , instead of being wound on a synthetic bobbin that is assembled to a stator. Such direct winding provides closer coupling of the armature to the stator. Certain features of the stator, such as the various chamfers, avoid saturation in certain portions of the magnetic circuit.
While the foregoing has described a preferred embodiment of the present invention, it is to be appreciated that the inventive principles may be practiced in any form that falls within the scope of the following claims. | An electric actuated control valve, such as an EGR valve, has a solenoid that can deliver useful force over a longer stroke for operating a valve element. | Concisely explain the essential features and purpose of the concept presented in the passage. | [
"CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority to and benefit of provisional patent application Serial No. 60/354,013, filed Jan. 31, 2002, the disclosure of which is incorporated by reference herein in its entirety.",
"FIELD OF THE INVENTION This invention relates generally to electric-actuated control valves, such as valves for controlling flow of fluids in automotive vehicle engine systems.",
"In particular, the invention relates to improvements for increasing the useful stroke of such a valve by enhancing the force vs.",
"stroke characteristic of the valve actuator.",
"Examples of such valves are exhaust gas recirculation (EGR) valves and fuel cell valves.",
"BACKGROUND OF THE INVENTION The actuator of certain control valves of automotive vehicle engine systems comprises a solenoid that comprises an electromagnet coil and a stator having an air gap at which magnetic flux acts on an armature.",
"The armature motion is transmitted to a valve element to control flow through a passage of the valve.",
"Armature motion is resisted by a return spring that acts on the armature, either directly or via the valve element, to bias the armature toward a position that causes the valve element to close the passage.",
"The stator air gap is defined by an upper pole piece that is disposed at an upper end of the coil and a lower pole piece at a lower end of the coil.",
"The pole pieces have respective annular hubs that fit into an interior space bounded by the coil, approaching each other from opposite ends of the coil.",
"The juxtaposed ends of the two hubs are spaced apart to define the air gap as a generally annular space within which the armature is centered and along which the armature can travel.",
"Electric current in the coil creates magnetic flux that passes from one hub through a portion of the air gap to the armature, through the armature, and back across another portion of the air gap to the other hub.",
"The flux creates an electromagnetic force on the armature, and the axial component of that force acts to displace the armature along the centerline of the solenoid against the resistance of the return spring.",
"In order to operate the valve from closed to open, the solenoid must apply a force that is greater than the sum of the bias force being applied by the return spring and any other forces acting on the valve.",
"For achieving improved control, it is desirable that the valve actuator be able to deliver increasing force over an increased stroke length.",
"However, certain constraints that are imposed on certain automotive vehicles, especially mass-produced vehicles that are subject to governmental regulation, make it impossible, impractical, and/or uneconomical simply to use a larger solenoid.",
"Accordingly, it is believed that a valve that is capable of delivering increasing force over an increased stroke length, without accompanying increases in size and weight that would be deemed unacceptable, would be useful to automotive vehicle manufacturers in complying with constraints imposed on the vehicles that they manufacture.",
"SUMMARY OF THE INVENTION The present invention relates to a valve that is capable of delivering increasing force over an increased stroke length, without accompanying increases in size and weight that would be deemed unacceptable.",
"One general aspect of the invention relates to an electric-actuated control valve for controlling flow of fluid in an automotive vehicle engine system.",
"The valve comprises a valve body comprising a passage having an inlet port for receiving fluid and an outlet port for delivering fluid.",
"A mechanism selectively positions a valve element to selectively restrict the passage.",
"The mechanism comprises a solenoid actuator comprising a bobbin having a tubular core of non-ferromagnetic metal and ferromagnetic pole pieces at axial ends of the tubular core.",
"An electromagnet coil comprising a length of magnetic wire is wound on the tubular core between flanges of the pole pieces.",
"The pole pieces form portions of a magnetic circuit for magnetic flux created by electric current in the coil and comprise hubs that protrude into the tubular core and have juxtaposed ends defining an air gap within the tubular core through which the magnetic flux passes between the pole piece hubs.",
"The mechanism further comprises an armature that is guided for motion axially of the tubular core for positioning the valve element and that comprises ferromagnetic material for conducting magnetic flux created at the air gap when electric current flows in the coil to cause an axial component of electromagnetic force to be exerted on the armature for positioning the valve element.",
"Another aspect relates to the solenoid actuator itself.",
"Still another aspect relates to a method of making the valve and the actuator.",
"The accompanying drawings, which are incorporated herein and constitute part of this specification, include a presently preferred embodiment of the invention, and together with a general description given above and a detailed description given below, serve to disclose principles of the invention in accordance with a best mode contemplated for carrying out the invention.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an engine system that comprises a valve in accordance with principles of the present invention.",
"FIG. 2 is a cross section view, in elevation, of an exemplary embodiment of an actuator of the valve of FIG. 1 embodying the present invention.",
"FIG. 3 is a graph plot for showing representative stroke length improvement that can be achieved with the present invention.",
"DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an exemplary emission control system 10 having an electric exhaust gas recirculation valve (EEGR valve) 12 associated with an internal combustion engine 14 to control the flow of exhaust gas being recirculated from an exhaust system 16 of the engine to an intake system 18 of the engine.",
"Valve 12 comprises a body containing a flow passage extending between a valve inlet port 20 communicated to exhaust system 16 and a valve outlet port 22 communicated to intake system 18 .",
"Valve 12 further comprises an electromagnetic actuator 24 , namely a solenoid, which is under control of an engine control system 26 to control the extent to which valve 12 allows exhaust gas to be recirculated through the flow passage in the valve body.",
"In the closed position of valve 12 that blocks exhaust gas recirculation, a preloaded return spring within the valve body is resiliently biasing a valve element to close on a valve seat in the flow passage, closing the flow passage to flow of exhaust gas between ports 20 and 22 .",
"As engine control system 26 delivers increasing electric current to actuator 24 , a point is reached where the current is sufficiently large to create sufficient force for overcoming the spring bias.",
"Further increases in current increasingly open the valve.",
"The improvement that is achieved by the present invention is accomplished through actuator 24 , detail of which appears in FIG. 2 .",
"Actuator 24 comprises stator structure 28 associated with an electromagnet coil 30 to form a portion of a magnetic circuit path.",
"The stator structure comprises an upper pole piece 32 , disposed at one end of the actuator coaxial with a centerline CL, a lower pole piece 34 disposed at the opposite end of the actuator coaxial with centerline CL, and an outer cylindrical shell 36 .",
"All three pieces 32 , 34 , 36 comprise ferromagnetic material.",
"Upper pole piece 32 comprises a circular end wall 40 and an annular walled hub 38 that extends interiorly from an interior face of end wall 40 .",
"The junction of the hub and flange comprises a chamfer 42 between a radially outer surface of hub 38 and the interior face of end wall 40 .",
"The chamfer ends at a shoulder 43 in the outer hub surface, and beyond that shoulder the outer hub surface continues axially as a circular cylindrical surface 44 .",
"Beyond surface 44 , the outer hub surface continues as a frustoconical surface 46 , finally ending at a narrow flat end face 48 that is perpendicular to centerline CL.",
"The radially inner surface of hub 38 comprises a circular cylindrical counterbore 50 extending into the hub from face 48 as far as an internal shoulder 52 .",
"The radially inner hub surface continues axially from shoulder 52 as a chamfer 54 , and then as a circular cylindrical bore 56 , finally ending via a chamfer 58 at an end face 60 that is perpendicular to centerline CL.",
"Counterbore 50 and bore 56 thereby form a blind hole in pole piece 32 that is centered on centerline CL.",
"Lower pole piece 34 comprises a central hub 62 and a circular flange 64 that girdles hub 62 intermediate opposite axial ends of hub 62 .",
"One portion of hub 62 that extends from an interior face of flange 64 comprises an annular wall.",
"The junction of flange 64 and that annular wall comprises a chamfer 66 extending between the interior face of flange 64 and the outer surface of the hub wall.",
"From chamfer 66 , the outer surface of the hub wall continues as a circular cylindrical surface 68 ending at an end face 70 that is perpendicular to centerline CL.",
"The portion of hub 62 extending from the exterior face of flange 64 comprises an annular wall whose radially outer surface is a circular cylindrical surface 72 beginning at flange 64 and ending at a shoulder 73 .",
"From shoulder 73 , the outer wall surface continues as a circular cylindrical surface 76 and ends at an end face 78 that is perpendicular to centerline CL.",
"Lower pole piece 34 further comprises a through-hole that forms the inner hub surface and comprises a circular cylindrical counterbore 80 extending from end face 70 and ending at an internal shoulder 82 .",
"A circular cylindrical bore 84 extends from shoulder 82 to end face 78 .",
"Pole pieces 32 , 34 are assembled to a non-ferromagnetic tube 88 , one pole piece at one end of the tube, the other pole piece at the opposite end.",
"Tube 88 has a circular cylindrical shape of uniform radial thickness.",
"One end of tube 88 fits over hub 38 , being centered on surface 44 and axially abutting shoulder 43 .",
"The other end of tube 88 fits over the upper end of hub 62 , being centered on surface 68 and abutting chamfer 66 .",
"The assembly of pole pieces 32 , 34 and tube 88 forms a bobbin on which magnet wire is wound to create coil 30 .",
"Ends of the wire are led through a plastic overmold 86 and a clearance opening (not shown) in flange 40 where they can be attached to electric terminals in a cap of the valve actuator (also not shown).",
"The cap terminals protrude externally from the cap material where they are bounded by a surround of cap material to form a connector adapted for mating connection with a wiring harness connector for connecting the coil to control system 26 .",
"The plastic overmold 86 separates the wound coil wire from direct contact with end wall 40 of upper pole piece 32 , and is believed useful in damping vibrations.",
"Although not shown in the drawing, a thin layer of insulating plastic or paper may be disposed around tube 88 and similar thin insulating sheets disposed over the interior face of end wall 40 and that of flange 64 for insulation between the coil wire and the metal parts of the stator structure.",
"A sleeve bearing 90 , carbon steel for example, is fit to surface 84 to provide guidance for axial travel of an armature 92 of actuator 24 .",
"Such an insert may not always be needed, and replaced by a sleeve of thin non-magnetic material.",
"Armature 92 is guided only on lower pole piece 34 and not the upper pole piece.",
"Armature 92 comprises ferromagnetic material having a circular cylindrical outer surface 94 guided by the inner surface of bearing 90 .",
"The axial length of the armature overlaps the hubs of both pole pieces.",
"At its lower end armature 92 comprises a valve actuating stem 96 that protrudes from lower pole piece 34 .",
"An air gap is present between confronting ends of hubs 38 and 62 within space bounded by coil 30 .",
"Armature 92 is disposed in the air gap between juxtaposed ends of the pole piece hubs.",
"When coil 30 is energized by electric current, magnetic flux passes from one hub across one portion of the air gap, through that portion of the armature disposed at the air gap, through another portion of the air gap, and to the other hub.",
"Exterior to coil 30 , the magnetic circuit is completed from one pole piece to the other through shell 36 .",
"Flanges 40 and 64 have matching circular edges, and shell 36 is fit to those edges.",
"The end of armature 92 disposed at the air gap has a shape that is believed beneficial in concentrating flux without saturation to improve the force vs.",
"travel characteristic of the actuator.",
"A frustoconical counterbore 95 is present in the end face of the armature, creating a raised annular rim 97 that bridges much of the distance between the confronting ends of the hubs of the respective pole pieces.",
"Rim 97 is the portion of the armature through which the magnetic flux is conducted between the pole pieces at the air gap and comprises a circular radially outer surface and a frostoconical tapered radially inner surface.",
"Rim 97 has a widening taper in the direction from the tapered wall of hub 38 toward hub 62 of pole piece 34 .",
"In the closed position of valve 10 , the preloaded return spring (not shown) is resiliently biasing the valve element to close the flow passage between ports 20 and 22 .",
"That spring forms an element of the internal valve mechanism, functioning via the valve element to resiliently bias armature 92 to an initial position along centerline CL when no current flows in coil 30 .",
"As electric current begins to increasingly flow through coil 30 , the magnetic circuit exerts increasing electromagnetic force urging armature 92 in the downward direction as viewed in FIG. 1 .",
"Once the force is large enough to overcome the bias of the preload force of the return spring, armature 92 begins to move downward, similarly moving the valve element and opening valve 10 to allow flow between the two ports.",
"The position to which the armature is displaced, and hence the extent to which the valve is allowed to open, is controlled by the electric current in coil 30 .",
"The actual control strategy for the valve is determined as part of the overall engine control strategy embodied in engine control system 26 .",
"Solenoid 24 , as described above, endows armature 92 with a longer useful stroke in comparison to certain other valves, as shown by Figure.",
"FIG. 3 is a graph plot showing armature force as a function of armature displacement for two different valves.",
"The graph plot 100 is for valve 12 while the graph plot 102 is for a similar valve that has a solenoid different from solenoid 24 of valve 12 .",
"It is evident that for a given amount of current in the respective coils, valve 12 delivers force that is not only larger, but that is delivered over a larger range of armature displacements.",
"Both plots are characterized by the presence of hysteresis.",
"For the example given, the useful stroke length has been almost doubled, with only about a 12% increase in volume of the actuator.",
"It is believed that the improvement provided by the invention arises because the coil is wound directly on tube 88 , instead of being wound on a synthetic bobbin that is assembled to a stator.",
"Such direct winding provides closer coupling of the armature to the stator.",
"Certain features of the stator, such as the various chamfers, avoid saturation in certain portions of the magnetic circuit.",
"While the foregoing has described a preferred embodiment of the present invention, it is to be appreciated that the inventive principles may be practiced in any form that falls within the scope of the following claims."
] |
CROSS REFERENCE TO RELATED APPLICATIONS
Cross reference is made to commonly assigned co-pending patent application Ser. No. 09/641,424 entitled “Solid State Traffic Light With Predictive Failure Mechanisms” filed Aug. 16, 2000, filed herewith, the teachings of which are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention is generally related to light sources, and more particularly to traffic signal lights including those incorporating both incandescent and solid state light sources.
BACKGROUND OF THE INVENTION
Traffic signal lights have been around for years and are used to efficiently control traffic through intersections. While traffic signals have been around for years, improvements continue to be made in the areas of traffic signal light control algorithms, traffic volume detection, and emergency vehicle detection.
There continues to be a need to be able to predict when a traffic signal light source will fail. The safety issues of an unreliable traffic signal are obvious. The primary failure mechanism of an incandescent light source is an abrupt termination of the light output caused by filament breakage. The primary failure mechanism of a solid state light source is gradual decreasing of light output over time, and then ultimately, no light output.
The current state of the art for solid state light sources is as direct replacements for incandescent light sources. The life time of traditional solid state light sources is far longer than incandescent light sources, currently having a useful operational life of 10-100 times that of traditional incandescent light sources. This additional life time helps compensate for the additional cost associated with solid state light sources.
However, solid state light sources are still traditionally used in the same way as incandescent light sources, that is, continuing to operate the solid state light source until the light output is insufficient or non existent, and then replacing the light source. The light output is traditionally measured by a person with a light meter, measuring the light output from the solid state light source from a Department of Transportation (DOT) “bucket”.
Other problems with traditional traffic signal light sources is the intense heat generated by the light source. In particular, temperature greatly affects the life time of solid state light sources. If the temperature can be reduced, the operational life of the solid state light source may increase between 3 fold and 10 fold. Traditionally, solid state light sources today are designed as individual light emitting diodes (LEDs) individually mounted to a printed circuit board (PCB), and placed in a protective enclosure. This protective enclosure produces a large amount of heat and has severe heat dissipation problems, thereby reducing the life of the solid state light source dramatically.
In addition to temperature, oxidation also greatly effects the lifetime of solid state light sources. For instance, when oxygen is allowed to combine with aluminum on an aluminum gallium arsenide phosphorus (AlInGaP) LED, oxidation will occur and the light output is significantly reduced.
With specific regards to solid state light sources, typical solid state light sources comprised of LEDs are traditionally too bright early in their life, and yet not bright enough in their later stages of life. Traditional solid state light sources used in traffic control signals are traditionally over driven initially so that when the light reduces later, the light output is still at a proper level meeting DOT requirements. However, this overdrive significantly reduces the life of the LED device due to the increased, and unnecessary, drive power and associated heat of the device during the early term of use. Thus, not only is the cost for operating the signal increased, but more importantly, the overall life of the device is significantly reduced by overdriving the solid state light source during the initial term of operation.
Still another problem with traditional light sources for traffic signals is detection of the light output using the traditional hand held meter. Ambient light greatly affects the accurate detection of light output from the light source. Therefore, it has been difficult in the past to precisely set the light output to a level that meets DOT standards, but which light source is not over driven to the point of providing more light than necessary, which as previously mentioned, increases temperature and degrades the useful life of the solid state device.
Still another problem in prior art traffic signals is that signal visibility needs to be controlled so only specific lanes of traffic are able to see the traffic light. An example is when a left turn lane has a green light, and an adjacent lane is designated as a straight lane. It is necessary for traffic in the left turn lane to see the green light. The current visibility control mechanism is mechanical, typically implementing a set of baffles inserted into the light system to carefully block the generated light from the unintended lane. The mechanical direction system is not very controllable because it is controlled in only one dimension, typically either up or down, or, either right or left, but not both. Consequently, the light is undesirable often seen in the adjacent lane. There is arisen a need for a better method to control the visibility range of a traffic signal.
Traditionally, old technology is typically replaced with new technology by simply disposing of the old technology traffic devices. Since most cities don't have the budget to replace all traffic control devices when new ones come to market, they have traditionally taken the position of replacing only a portion of the cities devices at any given time, thereby increasing the inventory needed for the city. Larger cities end up inventorying many different manufacture's traffic signals, some of which are not in production any longer. The added cost is not only for storage of inventoried items, but also the overhead of taking all different types of equipment to a repair site, or cataloging the different inventoried items at different locations.
With respect to alignment systems for traffic lights, traditionally alignment traffic control devices provide that one person points the generated light beam in the desired direction from a bucket while above the intersection, while another person stands in the traffic lanes to determine if the light is aligned properly. The person on the ground has to move over the entire field of view to check the light alignment. If the light is masked off (such as a turn arrow), there are more alignment iterations. There is desired a faster and more reliable method of aligning traffic signals.
Traffic lights also have a problem during darker conditions, i.e. at night or at dusk when the light is not well defined. This causes a problem if the light has to be masked off for any reason, whereby light may overlap to areas that should be off. This imprecise on/off boundary is called “ghosting”. There is a need to find an improved way to define the light/dark boundary of the traffic light to reduce ghosting. The ghosting is primarily caused by the angle the light hits on the “risers” on a Fresnel lens. A traffic light with a longer focal length reduces the angle, therefore decreasing the amount of ghosting. Therefore, devices with shorter focal lengths have increased ghosting. Another cause of ghosting is stray light from arrays of LED lights. Typical LED designs have a rather large intensity peek, that is, a less uniform beam of light being generated from the array.
SUMMARY OF THE INVENTION
The present invention achieves many technical advantages as an improved traffic control signal. A solid state light source has many advantageous features including the ability to predict failure of the light source, as well as an extended life time by using an external heatsink having a solar shield facilitating ambient airflow therepast to sink heat away from an LED light array, hermetically sealing the array of LEDs with a glass-to-metal seal, and controlling the light output over time to prevent overdrive of the LED array. Other features of the present invention include providing a constant output of light from a solid state light source by providing optical feedback of light and electronic filtering to accurately detect and discern generated light from ambient light.
Other advantages of the solid state light source include an electronically steerable light beam having the ability to steer light into two dimensions, insuring only the intended lane of traffic is able to visually perceive the beam of light. In addition, the solid state light source is modularly upgradeable to allow upgrades of existing components, and the adaption of new components to keep the traffic signal state of the art. An optical sight alignment mechanism is also provided with the light source allowing a technician at the light source to determine where a beam of light generated from the light array is directed, without requiring the assistance of an on ground technician. Yet another feature of the present invention is an opto-electronic rolloff control for a light source reducing ghosting of a generated beam of light.
The solid state light of the present invention includes several new features, and several improved features, providing a state of the art solid state light source that overcomes the limitations of prior art traffic sources, including those with conventional solid state light sources.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 A and FIG. 2A is a front perspective view and rear perspective view, respectively, of a solid state light apparatus according to a first preferred embodiment of the present invention including an optical alignment eye piece;
FIG. 2 A and FIG. 2B is a front perspective view and a rear perspective view, respectively, of a second preferred embodiment having a solar louvered external air cooled heatsink;
FIG. 3 is a side sectional view of the apparatus shown in FIG. 1 illustrating the electronic and optical assembly and lens system comprising an array of LEDs directly mounted to a heatsink, directing light through a diffuser and through a Fresnel lens;
FIG. 4 is a perspective view of the electronic and optical assembly comprising the LED array, lense holder, light diffuser, power supply, main motherboard and daughterboard;
FIG. 5 is a side view of the assembly of FIG. 4 illustrating the array of LEDs being directly mounted to the heatsink, below respective lenses and disposed beneath a light diffuser, the heatsink for terminally dissipating generated heat;
FIG. 6 is a top view of the electronics assembly of FIG. 4;
FIG. 7 is a side view of the electronics assembly of FIG. 4;
FIG. 8 is a top view of the lens holder adapted to hold lenses for the array of LEDs;
FIG. 9 is a sectional view taken alone lines 9 — 9 in FIG. 8 illustrating a shoulder and side wall adapted to securely receive a respective lens for a LED mounted thereunder;
FIG. 10 is a top view of the heatsink comprised of a thermally conductive material and adapted to securingly receive each LED, the LED holder of FIG. 8, as well as the other componentry;
FIG. 11 is a side view of the light diffuser depicting its radius of curvature;
FIG. 12 is a top view of the light diffuser of FIG. 11 illustrating the mounting flanges thereof;
FIG. 13 is a top view of a Fresnel lens as shown in FIG. 3;
FIG. 14A is a view of a remote monitor displaying an image generated by a video camera in the light apparatus to facilitate electronic alignment of the LED light beam;
FIG. 14B is a perspective view of the lid of the apparatus shown in FIG. 1 having a grid overlay for use with the optical alignment system;
FIG. 15 is a perspective view of the optical alignment system eye piece adapted to connect to the rear of the light unit shown in FIG. 1;
FIG. 16 is a schematic diagram of the control circuitry disposed on the daughterboard and incorporating various features of the invention including control logic, as well as light detectors for sensing ambient light and reflected generated light from the light diffuser used to determine and control the light output from the solid state light;
FIG. 17 is an algorithm depicting the sensing of ambient light and backscattered light to selectably provide a constant output of light;
FIG. 18 a AND FIG. 18B are side sectional views of an alternative preferred embodiment including a heatsink with recesses, with the LED's wired in parallel and series, respectively;
FIG. 19 is an algorithm depicting generating information indicative of the light operation, function and prediction of when the said state apparatus will fail or provide output below acceptable light output;
FIGS. 20 and 21 illustrate operating characteristics of the LEDs as a function of PWM duty cycles and temperature as a function of generated output light;
FIG. 22 is a block diagram of a modular light apparatus having selectively interchangeable devices that are field replaceable;
FIG. 23 is a perspective view of a light guide having a light channel for each LED to direct the respective LED light to the diffuser;
FIG. 24 shows a top view of FIG. 23 of the light guide for use with the diffuser; and
FIG. 25 shows a side sectional view taken along line 24 — 24 in FIG. 3 illustrating a separate light guide cavity for each LED extending to the light diffuser.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to FIG. 1A, there is illustrated generally at 10 a front perspective view of a solid state lamp apparatus according to a first preferred embodiment of the present invention. Light apparatus 10 is seen to comprise a trapezoidal shaped housing 12 , preferably comprised of plastic formed by a plastic molding injection techniques, and having adapted to the front thereof a pivoting lid 14 . Lid 14 is seen to have a window 16 , as will be discussed shortly, permitting light generated from within housing 12 to be emitted as a light beam therethrough. Lid 14 is selectively and securable attached to housing 12 via a hinge assemble 17 and secured via latch 18 which is juxtaposed with respect to a housing latch 19 , as shown.
Referring now to FIG. 1 B and FIG. 2B, there is illustrated a second preferred embodiment of the present invention at 32 similar to apparatus 10 , whereby a housing 33 includes a solar louver 34 as shown in FIG. 2 B. The solar louver 34 is secured to housing 33 and disposed over a external heatsink 20 which shields the external heatsink 20 from solar radiation while permitting outside airflow across the heatsink 20 and under the shield 34 , thereby significantly improving cooling efficiency as will be discussed more shortly.
Referring to FIG. 2A, there is shown light apparatus 10 of FIG. 1A having a rear removable back member 20 comprised of thermally conductive material and forming a heatsink for radiating heat generated by the internal solid state light source, to be discussed shortly. Heatsink 20 is seen to have secured thereto a pair hinges 22 which are rotatably coupled to respective hinge members 23 which are securely attached and integral to the bottom of the housing 12 , as shown. Heatsink 20 is further seen to include a pair of opposing upper latches 24 selectively securable to respective opposing latches 25 forming an integral portion of and secured to housing 12 . By selectively disconnecting latches 24 from respective latches 25 , the entire rear heatsink 20 may be pivoted about members 23 to access the internal portion of housing 12 , as well as the light assembly secured to the front surface of heatsink 20 , as will be discussed shortly in regards to FIG. 3 .
Still referring to FIG. 2A, light apparatus 10 is further seen to include a rear eye piece 26 including a U-shaped bracket extending about heatsink 20 and secured to housing 12 by slidably locking into a pair of respective locking members 29 securely affixed to respective sidewalls of housing 12 . Eye piece 26 is also seen to have a cylindrical optical sight member 28 formed at a central portion of, and extending rearward from, housing 12 to permit a user to optically view through apparatus 10 via optically aligned window 16 to determine the direction a light beam, and each LED, is directed, as will be described in more detail with reference to FIG. 14 and FIG. 15 . Also shown is housing 12 having an upper opening 30 with a serrated collar centrally located within the top portion of housing 12 , and opposing opening 30 at the lower end thereof, as shown in FIG. 3 . Openings 30 facilitate securing apparatus 10 to a pair of vertical posts allowing rotation laterally thereabout.
Referring now to FIG. 3, there is shown a detailed cross sectional view taken along line 3 — 3 in FIG. 1, illustrating a solid state light assembly 40 secured to rear heatsink 20 in such an arrangement as to facilitate the transfer of heat generated by light assembly 40 to heatsink 20 for the dissipation of heat to the ambient via heatsink 20 .
Solid state light assembly 40 is seen to comprise an array of light emitting diodes (LEDs) 42 aligned in a matrix, preferably comprising an 8×8 array of LEDs each capable of generating a light output of 1-3 lumens. However, limitation to the number of LEDs or the light output of each is not to be inferred. Each LED 42 is directly bonded to heatsink 20 within a respective light reflector comprising a recess defined therein. Each LED 42 is hermetically sealed by a glass material sealingly diffused at a low temperature over the LED die 42 and the wire bond thereto, such as 8000 Angstroms of, SiO 2 or Si 3 N 4 material diffused using a semiconductor process. The technical advantages of this glass to metal hermetic seal over plastic/epoxy seals is significantly a longer LED life due to protecting the LED die from oxygen, humidity and other contaminants. If desired, for more light output, multiple LED dies 42 can be disposed in one reflector recess. Each LED 42 is directly secured to, and in thermal contact arrangement with, heatsink 20 , whereby each LED is able to thermally dissipate heat via the bottom surface of the LED. Interfaced between the planar rear surface of each LED 42 is a thin layer of heat conductive material 46 , such as a thin layer of epoxy or other suitable heat conductive material insuring that the entire rear surface of each LED 42 is in good thermal contact with rear heatsink 20 to efficiently thermally dissipate the heat generated by the LEDs. Each LED connected electrically in parallel has its cathode electrically coupled to the heatsink 20 , and its Anode coupled to drive circuitry disposed on daughterboard 60 . Alternatively, if each LED is electrically connected in series, the heatsink 20 preferably is comprised of an electrically non-conductive material such as ceramic.
Further shown in FIG. 3 is a main circuit board 48 secured to the front surface of heatsink 20 , and having a central opening for allowing LED to pass generated light therethrough. LED holder 44 mates to the main circuit board 48 above and around the LED's 42 , and supports a lens 86 above each LED. Also shown is a light diffuser 50 secured above the LEDs 42 by a plurality of standoffs 52 , and having a rear curved surface 54 spaced from and disposed above the LED solid state light source 40 , as shown. Each lens 86 (FIG. 9) is adapted to ensure each LED 42 generates light which impinges the rear surface 54 having the same surface area. Specifically, the lenses 86 at the center of the LED array have smaller radius of curvature than the lenses 86 covering the peripheral LEDs 42 . The diffusing lenses 46 ensure each LED illuminates the same surface area of light diffuser 50 , thereby providing a homogeneous (uniform) light beam of constant intensity.
A daughter circuit board 60 is secured to one end of heatsink 20 and main circuit board 48 by a plurality of standoffs 62 , as shown. At the other end thereof is a power supply 70 secured to the main circuit board 48 and adapted to provide the required drive current and drive voltage to the LEDs 42 comprising solid state light source 40 , as well as electronic circuitry disposed on daughterboard 60 , as will be discussed shortly in regards to the schematic diagram shown in FIG. 16 . Light diffuser 50 uniformly diffuses light generated from LEDs 42 of solid state light source 40 to produce a homogeneous light beam directed toward window 16 .
Window 16 is seen to comprise a lens 70 , and a Fresnel lens 72 in direct contact with lens 70 and interposed between lens 70 and the interior of housing 12 and facing light diffuser 50 and solid state light source 40 . Lid 14 is seen to have a collar defining a shoulder 76 securely engaging and holding both of the round lens 70 and 72 , as shown, and transparent sheet 73 having defined thereon grid 74 as will be discussed further shortly. One of the lenses 70 or 72 are colored to produce a desired color used to control traffic including green, yellow, red, white and orange.
It has been found that with the external heatsink being exposed to the outside air the outside heatsink 20 cools the LED die temperature up to 50° C. over a device not having a external heatsink. This is especially advantageous when the sun setting to the west late in the afternoon such as at an elevation of 10° or less, when the solar radiation directed in to the lenses and LEDs significantly increasing the operating temperature of the LED die for westerly facing signals. The external heatsink 20 prevents extreme internal operating air and die temperatures and prevents thermal runaway of the electronics therein.
Referring now to FIG. 4, there is shown the electronic and optic assembly comprising of solid state light source 40 , light diffuser 50 , main circuit board 48 , daughter board 60 , and power supply 70 . As illustrated, the electronic circuitry on daughter board 60 is elevated above the main board 48 , whereby standoffs 62 are comprised of thermally nonconductive material.
Referring to FIG. 5, there is shown a side view of the assembly of FIG. 4 illustrating the light diffuser 50 being axially centered and disposed above the solid state LED array 40 . Diffuser 50 , in combination with the varying diameter lenses 86 , facilitates light generated from the LEDs 42 to be uniformly disbursed and have uniform intensity and directed upwardly as a light beam toward the lens 70 and 72 , as shown in FIG. 3 .
Referring now to FIG. 6, there is shown a top view of the assembly shown in FIG. 4, whereby FIG. 7 illustrates a side view of the same.
Referring now to FIG. 8, there is shown a top view of the lens holder 44 comprising a plurality of openings 80 each adapted to receive one of the LED lenses 86 hermetically sealed to and bonded thereover. Advantageously, the glass to metal hermetic seal has been found in this solid state light application to provide excellent thermal conductivity and hermetic sealing characteristics. Each opening 80 is shown to be defined in a tight pack arrangement about the plurality of LEDs 42 . As previously mentioned, the lenses 86 at the center of the array, shown at 81 , have a smaller curvature diameter than the lenses 86 over the perimeter LEDs 42 to increase light dispersion and ensure uniform light intensity impinging diffuser 50 .
Referring to FIG. 9, there is shown a cross section taken alone line 9 — 9 in FIG. 8 illustrating each opening 80 having an annular shoulder 82 and a lateral sidewall 84 defined so that each cylindrical lens 86 is securely disposed within opening 80 above a respective LED 42 . Each LED 42 is preferably mounted to heatsink 20 using a thermally conductive adhesive material such as epoxy to ensure there is no air gaps between the LED 42 and the heatsink 20 . The present invention derives technical advantages by facilitating the efficient transfer of heat from LED 42 to the heatsink 20 .
Referring now to FIG. 10, there is shown a top view of the main circuit board 48 having a plurality of openings 90 facilitating the attachment of standoffs 62 securing the daughter board above an end region 92 . The power supply 48 is adapted to be secured above region 94 and secured via fasteners disposed through respective openings 96 at each corner thereof. Center region 98 is adapted to receive and have secured thereagainst in a thermal conductive relationship the LED holder 42 with the thermally conductive material 46 being disposed thereupon. The thermally conductive material preferably comprises of epoxy, having dimensions of, for instance, 0.05 inches. A large opening 99 facilitates the attachment of LED's 42 to the heatsink 20 , and such that light from the LEDs 42 is directed to the light diffuser 50 .
Referring now to FIG. 11, there is shown a side elevational view of diffuser 50 having a lower concave surface 54 , preferably having a radius A of about 2.4 inches, with the overall diameter B of the diffuser including a flange 55 being about 6 inches. The depth of the rear surface 52 is about 1.85 inches as shown as dimension C.
Referring to FIG. 12, there is shown a top view of the diffuser 50 including the flange 56 and a plurality of openings 58 in the flange 56 for facilitating the attachment of standoffs 52 to and between diffuser 50 and the heatsink 20 , shown in FIG. 4 .
Referring now to FIG. 13 there is shown the Fresnel lens 72 , preferably having a diameter D of about 12.2 inches. However, limitation to this dimension is not to be inferred, but rather, is shown for purposes of the preferred embodiment of the present invention. The Fresnel lens 72 has a predetermined thickness, preferably in the range of about {fraction (1/16)} inches. This lens is typically fabricated by being cut from a commercially available Fresnel lens.
Referring now back to FIG. 1 A and FIG. 1B, there is shown generally at 56 a video camera oriented to view forward of the front face of solid state lamp 10 and 30 , respectively. The view of this video camera 56 is precisionally aligned to view along and generally parallel to the central longitudinal axis shown at 58 that the beam of light generated by the internal LED array is oriented. Specifically, at large distances, such as greater than 20 feet, the video camera 56 generates an image having a center of the image generally aligned with the center of the light beam directed down the center axis 58 . This allows the field technician to remotely electronically align the orientation of the light beam referencing this video image.
For instance, in one preferred embodiment the control electronics 60 has software generating and overlaying a grid along with the video image for display at a remote display terminal, such as a LCD or CRT display shown at 59 in FIG. 14 A. This video image is transmitted electronically either by wire using a modem, or by wireless communication using a transmitter allowing the field technician on the ground to ascertain that portion of the road that is in the field of view of the generated light beam. By referencing this displayed image, the field technician can program which LEDs 42 should be electronically turned on, with the other LEDs 42 remaining off, such that the generated light beam will be focused by the associated optics including the Fresnel lens 72 , to the proper lane of traffic. Thus, on the ground, the field technician can electronically direct the generated light beam from the LED arrays, by referencing the video image, to the proper location on the ground without mechanical adjustment at the light source, such as by an operator situated in a DOT bucket. For instance, if it is intended that the objects viewable and associated with the upper four windows defined by the grid should be illuminated, such as those objects viewable through the windows labeled as W in FIG. 14A, the LEDs 42 associated with the respective windows “W” will be turned on, with the rest of the LEDs 46 associated with the other windows being turned off. Preferably, there is one LED 46 associated with each window defined by the grid. Alternatively, a transparent sheet 73 having a grid 74 defining windows 78 can be laid over the display surface of the remote monitor 59 whereby each window 78 corresponds with one LED. For instance, there may be 64 windows associated with the 64 LEDs of the LED array. Individual control of the respective LEDs is discussed hereafter in reference to FIG. 14 A. The video camera 56 , such as a CCD camera or a CMCS camera, is physically aligned alone the central axis 58 , such that at extended distances the viewing area of the camera 56 is generally along the axis 58 and thus is optically aligned with regards to the normal axis 58 for purposes of optical alignment.
Referring now to FIG. 14B, there is illustrated the lid 14 , the hinge members 17 , and the respective latches 18 . Holder 14 is seen to further have an annular flange member 70 defining a side wall about window 16 , as shown. Further shown the transparent sheet 73 and grid 74 comprising of thin line markings defined over openings 16 defining windows 78 . The sheet can be selectively placed over window 16 for alignment, and which is removable therefrom after alignment. Each window 78 is precisionally aligned with and corresponds to one sixty four (64) LEDs 42 . Indicia 79 is provided to label the windows 78 , with the column markings preferably being alphanumeric, and the columns being numeric. The windows 78 are viable through optical sight member 28 , via an opening in heatsink 20 . The objects viewed in each window 78 are illuminated substantially by the respective LED 42 , allowing a technician to precisionally orient the apparatus 10 so that the desired LEDs 42 are oriented to direct light along a desired path and be viewed in a desired traffic lane. The sight member 28 may be provided with cross hairs to provide increased resolution in combination with the grid 74 for alignment.
Moreover, electronic circuitry 100 on daughterboard 60 can drive only selected LEDs 42 or selected 4×4 portions of array 40 , such as a total of 16 LED's 42 being driven at any one time. Since different LED's have lenses 86 with different radius of curvature different thicknesses, or even comprised of different materials, the overall light beam can be electronically steered in about a 15° cone of light relative to a central axis defined by window 16 and normal to the array center axis.
For instance, driving the lower left 4×4 array of LEDs 42 , with the other LEDs off, in combination with the diffuser 50 and lens 70 and 72 , creates a light beam +7.5 degrees above a horizontal axis normal to the center of the 8×8 array of LEDs 42 , and +7.5 degrees right of a vertical axis. Likewise, driving the upper right 4×4 array of LEDs 42 would create a light beam +10 degrees off the horizontal axis and +7.5 degrees to the right of a normalized vertical axis and −7.5 degrees below a vertical axis. The radius of curvature of the center lenses 86 may be, for instance, half that of the peripheral lenses 86 . A beam steerable ±7.5 degrees in 1-2 degree increments is selectable. This feature is particularly useful when masking the opening 16 , such as to create a turn arrow. This filter reduces ghosting or roll-off, which is stray light being directed in an unintended direction and viewable from an unintended traffic lane.
The electronically controlled LED array provides several technical advantages including no light is blocked, but rather is electronically steered to control a beam direction. Low power LEDs are used, whereby the small number of the LEDs “on” (i.e. 4 of 64) consume a total power about 1-2 watts, as opposed to an incandescent prior art bulb consuming 150 watts or a flood 15 watt LED which are masked or lowered. The present invention reduces power and heat generated thereby.
Referring now to FIG. 15, there is shown a perspective view of the eye piece 26 as well as the optical sight member 28 , as shown in FIG. 1, the center axis of optical sight member 28 is oriented along the center of the 8×8 LED array.
Referring now to FIG. 16, there is shown at 100 a schematic diagram of the circuitry controlling light apparatus 10 . Circuit 10 is formed on the daughter board 60 , and is electrically connected to the LED solid state light source 40 , and selectively drives each of the individual LEDs 42 comprising the array. Depicted in FIG. 16 is a complex programmable logic device (CPLD) shown as U 1 . CPLD U 1 is preferably an off-the-shelf component such as provided by Maxim Corporation, however, limitation to this specific part is not to be inferred. For instance, discrete logic could be provided in place of CPLD U 1 to provide the functions as is described here, with it being understood that a CPLD is the preferred embodiment is of the present invention. CPLD U 1 has a plurality of interface pins, and this embodiment, shown to have a total of 144 connection pins. Each of these pin are numbered and shown to be connected to the respective circuitry as will now be described.
Shown generally at 102 is a clock circuit providing a clock signal on line 104 to pin 125 of the CPLD U 1 . Preferably, this clock signal is a square wave provided at a frequency of 32.768 KHz. Clock circuit 102 is seen to include a crystal oscillator 106 coupled to an operational amplifier U 5 and includes associated trim components including capacitors and resistors, and is seen to be connected to a first power supply having a voltage of about 3.3 volts.
Still referring to FIG. 16, there is shown at 110 a power up clear circuit comprised of an operational amplifier shown at U 6 preferably having the non-inverting output coupled to pin 127 of CPLD U 1 . The inverting input is seen to be coupled between a pair of resistors providing a voltage divide circuit, providing approximately a 2.425 volt reference signal based on a power supply of 4.85 volts being provided to the positive rail of the voltage divide network. The inverting input is preferably coupled to the 4.85 voltage reference via a current limiting resistor, as shown.
As shown at 112 , an operational amplifier U 9 is shown to have its non-inverting output connected to pin 109 of CPLD U 1 . Operational amplifier U 9 provides a power down function.
Referring now to circuit 120 , there is shown a light intensity detection circuit detecting ambient light intensity and comprising of a photodiode identified as PD 1 . An operational amplifier depicted as U 7 is seen to have its non-inverting input coupled to input pin 99 of CPLD U 1 . The non-inverting input of amplifier U 7 is connected to the anode of photodiode PD 1 , which photodiode has its cathode connected via a capacitor to the second power supply having a voltage of about 4.85 volts. The non-inverting input of amplifier U 7 is also connected via a diode Q 1 , depicted as a transistor with its emitter tied to its base and provided with a current limiting resistor. The inverting input of amplifier U 7 is connected via a resistor to input 108 of CPLD U 1 .
Shown at 122 is a similar light detection circuit detecting the intensity of backscattered light from Fresnel lens 72 as shown at 124 in FIG. 3, and based around a second photodiode PD 2 , including an amplifier U 10 and a diode Q 2 . The non-inverting output of amplifier U 10 , forming a buffer, is connected to pin 82 of CPLD U 1 .
An LED drive connector is shown at 130 serially interfaces LED drive signal data to drive circuitry of the LEDs 42 . (Inventors please describe the additional drive circuit schematic).
Shown at 140 is another connector adapted to interface control signals from CPLD U 1 to an initiation control circuit for the LED's.
Each of the LEDs 42 is individually controlled by CPLD U 1 whereby the intensity of each LED 42 is controlled by the CPLD U 1 selectively controlling a drive current thereto, a drive voltage, or adjusting a duty cycle of a pulse width modulation (PWM) drive signal, and as a function of sensed optical feedback signals derived from the photodiodes as will be described shortly here, in reference to FIG. 17 .
Referring to FIG. 17 in view of FIG. 3, there is illustrated how light generated by solid state LED array 40 is diffused by diffuser 50 , and a small portion 124 of which is back-scattered by the inner surface of Fresnel lens 72 back toward the surface of daughter board 60 . The back-scattered diffused light 124 is sensed by photodiodes PD 2 , shown in FIG. 16 . The intensity of this back-scattered light 124 is measured by circuit 122 and provided to CPLD U 1 . CPLD U 1 measures the intensity of the ambient light via circuit 120 using photodiode PD 1 . The light generated by LED's 42 is preferably distinguished by CPLD U 1 by strobing the LEDs 42 using pulse width modulation (PWM) to discern ambient light (not pulsed) from the light generated by LEDs 42 .
CPLD U 1 individually controls the drive current, drive voltage, or PWM duty cycle to each of the respective LEDs 42 as a function of the light detected by circuits 120 and 122 . For instance, it is expected that between 3 and 4% of the light generated by LED array 40 will back-scatter back from the fresnel lens 72 toward to the circuitry 100 disposed on daughter board 60 for detection. By normalizing the expected reflected light to be detected by photodiodes PD 2 in circuit 122 , for a given intensity of light to be emitted by LED array 40 through window 16 of lid 14 , optical feedback is used to ensure an appropriate light output, and a constant light output from apparatus 10 .
For instance, if the sensed back-scattered light, depicted as rays 124 in FIG. 3, is detected by photodiodes PD 2 to fall about 2.5% from the normalized expected light to be sensed by photodiodes PD 2 , such as due to age of the LEDs 42 , CPLD U 1 responsively increases the drive current to the LEDs a predicted percentage, until the back-scattered light as detected by photodiodes PD 2 is detected to be the normalized sensed light intensity. Thus, as the light output of LEDs 42 degrade over time, which is typical with LEDs, circuit 100 compensates for such degradation of light output, as well as for the failure of any individual LED to ensure that light generated by array 40 and transmitted through window 16 meets Department of Transportation (DOT) standards, such as a 44 point test. This optical feedback compensation technique is also advantageous to compensate for the temporary light output reduction when LEDs become heated, such as during day operation, known as the recoverable light, which recoverable light also varies over temperatures as well. Permanent light loss is over time of operation due to degradation of the chemical composition of the LED semiconductor material.
Preferably, each of the LEDs is driven by a pulse width modulated (PWM) drive signal, providing current during a predetermined portion of the duty cycle, such as for instance, 50%. As the LEDs age and decrease in light output intensity, and also during a day due to daily temperature variations, the duty cycle may be responsively, slowly and continuously increased or adjusted such that the duty cycle is appropriate until the intensity of detected light by photodiodes PD 2 is detected to be the normalized detected light. When the light sensed by photodides PD 2 are determined by controller 60 to fall below a predetermined threshold indicative of the overall light output being below DOT standards, a notification signal is generated by the CPLD U 1 which may be electronically generated and transmitted by an RF modem, for instance, to a remote operator allowing the dispatch of service personnel to service the light. Alternatively, the apparatus 10 can responsively be shut down entirely.
Referring now to FIG. 18 A and FIG. 18B, there is shown an alternative preferred embodiment of the present invention including a heatsink 200 machined or stamped to have an array of reflectors 202 . Each recess 202 is defined by outwardly tapered sidewalls 204 and a base surface 208 , each recess 202 having mounted thereon a respective LED 42 . A lens array having a separate lens 210 for each LED 42 is secured to the heatsink 200 over each recess 202 , eliminating the need for a lens holder. The tapered sidewalls 206 serve as light reflectors to direct generated light through the respective lens 210 at an appropriate angle to direct the associated light to the diffuser 50 having the same surface area of illumination for each LED 42 . In one embodiment, as shown in FIG. 18A, LEDs 42 are electrically connected in parallel. The cathode of each LED 42 is electrically coupled to the electrically conductive heatsink 200 , with a respective lead 212 from the anode being coupled to drive circuitry 216 disposed as a thin film PCB 45 adhered to the surface of the heatsink 200 , or defined on the daughterboard 60 as desired. Alternatively, as shown in FIG. 18B, each of the LED's may be electrically connected in series, such as in groups of three, and disposed on an electrically non-conductive thermally conductive material 43 such as ceramic, diamond, SiN or other suitable materials. In a further embodiment, the electrically non-conductive thermally conductive material may be formed in a single process by using a semiconductor process, such as diffusing a thin layer of material in a vacuum chamber, such as 8000 Angstroms of SiN, which a further step of defining electrically conductive circuit traces 45 on this thin layer.
FIG. 19 shows an algorithm controller 60 applies for predicting when the solid state light apparatus will fail, and when the solid state light apparatus will produce a beam of light having an intensity below a predetermined minimum intensity such as that established by the DOT. Referring to the graphs in FIG. 20 and 21, the known operating characteristics of the particular LEDs produced by the LED manufacture are illustrated and stored in memory, allowing the controller 60 to predict when the LED is about the fail. Knowing the LED drive current operating temperature, and total time the LED as been on, the controller 60 determines which operating curve in FIG. 20 and FIG. 21 applies to the current operating conditions, and determines the time until the LED will degrade to a performance level below spec, i.e. below DOT minimum intensity requirements.
FIG. 22 depicts a block diagram of the modular solid state traffic light device. The modular field-replaceable devices are each adapted to selectively interface with the control logic daughterboard 60 via a suitable mating connector set. Each of these modular field replacable devices 216 are preferably embodied as a separate card, with possibly one or more feature on a single field replacable card, adapted to attach to daughterboard 60 by sliding into or bolting to the daughterboard 60 . The devices can be selected from, alone or in combination with, a pre-emption device, a chemical sniffer, a video loop detector, an adaptive control device, a red light running (RLR) device, and an in-car telematic device, infrared sensors to sense people and vehicles under fog, rain, smode and other adverse visual conditions, automobile emission monitoring, various communication links, electronically steerable beam, exhaust emission violations detection, power supply predictive failure analysis, or other suitable traffic devices.
The solid state light apparatus 10 of the present invention has numerous technical advantages, including the ability to sink heat generated from the LED array to thereby reduce the operating temperature of the LEDs and increase the useful life thereof. Moreover, the control circuitry driving the LEDs includes optical feedback for detecting a portion of the back-scattered light from the LED array, as well as the intensity of the ambient light, facilitating controlling the individual drive currents, drive voltages, or increasing the duty cycles of the drive voltage, such that the overall light intensity emitted by the LED array 40 is constant, and meets DOT requirements. The apparatus is modular in that individual sections can be replaced at a modular level as upgrades become available, and to facilitate easy repair. With regards to circuitry 100 , CPLD U 1 is securable within a respective socket, and can be replaced or reprogrammed as improvements to the logic become available. Other advantages include programming CPLD U 1 such that each of the LEDs 42 comprising array 40 can have different drive currents or drive voltages to provide an overall beam of light having beam characteristics with predetermined and preferably parameters. For instance, the beam can be selectively directed into two directions by driving only portions of the LED array in combination with lens 70 and 72 . One portion of the beam may be selected to be more intense than other portions of the beam, and selectively directed off axis from a central axis of the LED array 40 using the optics and the electronic beam steering driving arrangement.
Referring now to FIG. 23, there is shown at 220 a light guide device having a concave upper surface and a plurality of vertical light guides shown at 222 . One light guide 222 is provided for and positioned over each LED 42 , which light guide 222 upwardly directs the light generated by the respective LED 42 to impinge the outer surface of the diffuser 54 . The guides 222 taper outwardly at a top end thereof, as shown in FIG. 24 and FIG. 25, such that the area at the top of each light guide 222 is identical. Thus each LED 42 illuminates an equal surface area of the light diffuser 54 , thereby providing a uniform intensity light beam from light diffuser 54 . A thin membrane 224 defines the light guide, like a honeycomb, and tapers outwardly to a point edge at the top of the device 220 . These point edges are separated by a small vertical distance D shown in FIG. 25, such as 1 mm, from the above diffuser 54 to ensure uniform lighting at the transistion edges of the light guides 222 while preventing bleeding of light laterally between guides, and to prevent light roll-off by generating a homogeneous beam of light. Vertical recesses 226 permit standoffs 52 extending along the sides of device 220 (see FIG. 3) to support the peripheral edge of the diffuser 54 .
While the invention has been described in conjunction with preferred embodiments, it should be understood that modifications will become apparent to those of ordinary skill in the art and that such modifications are therein to be included within the scope of the invention and the following claims. | An electrically steerable solid state light apparatus is ideally suited for traffic controls. There exist many applications where a driver wishes limited viewing angles of traffic signals for safety, one example being left hand turn arrows. Current state of the art for solid state traffic signals involves the use of a mechanical louver to block the light from the unintended traffic lanes. This approach reduces the intensity of the light and customization of the viewing angle available to the DOT (Department of Transportation). | Identify the most important aspect in the document and summarize the concept accordingly. | [
"CROSS REFERENCE TO RELATED APPLICATIONS Cross reference is made to commonly assigned co-pending patent application Ser.",
"No. 09/641,424 entitled “Solid State Traffic Light With Predictive Failure Mechanisms”",
"filed Aug. 16, 2000, filed herewith, the teachings of which are incorporated herein by reference.",
"FIELD OF THE INVENTION The present invention is generally related to light sources, and more particularly to traffic signal lights including those incorporating both incandescent and solid state light sources.",
"BACKGROUND OF THE INVENTION Traffic signal lights have been around for years and are used to efficiently control traffic through intersections.",
"While traffic signals have been around for years, improvements continue to be made in the areas of traffic signal light control algorithms, traffic volume detection, and emergency vehicle detection.",
"There continues to be a need to be able to predict when a traffic signal light source will fail.",
"The safety issues of an unreliable traffic signal are obvious.",
"The primary failure mechanism of an incandescent light source is an abrupt termination of the light output caused by filament breakage.",
"The primary failure mechanism of a solid state light source is gradual decreasing of light output over time, and then ultimately, no light output.",
"The current state of the art for solid state light sources is as direct replacements for incandescent light sources.",
"The life time of traditional solid state light sources is far longer than incandescent light sources, currently having a useful operational life of 10-100 times that of traditional incandescent light sources.",
"This additional life time helps compensate for the additional cost associated with solid state light sources.",
"However, solid state light sources are still traditionally used in the same way as incandescent light sources, that is, continuing to operate the solid state light source until the light output is insufficient or non existent, and then replacing the light source.",
"The light output is traditionally measured by a person with a light meter, measuring the light output from the solid state light source from a Department of Transportation (DOT) “bucket.”",
"Other problems with traditional traffic signal light sources is the intense heat generated by the light source.",
"In particular, temperature greatly affects the life time of solid state light sources.",
"If the temperature can be reduced, the operational life of the solid state light source may increase between 3 fold and 10 fold.",
"Traditionally, solid state light sources today are designed as individual light emitting diodes (LEDs) individually mounted to a printed circuit board (PCB), and placed in a protective enclosure.",
"This protective enclosure produces a large amount of heat and has severe heat dissipation problems, thereby reducing the life of the solid state light source dramatically.",
"In addition to temperature, oxidation also greatly effects the lifetime of solid state light sources.",
"For instance, when oxygen is allowed to combine with aluminum on an aluminum gallium arsenide phosphorus (AlInGaP) LED, oxidation will occur and the light output is significantly reduced.",
"With specific regards to solid state light sources, typical solid state light sources comprised of LEDs are traditionally too bright early in their life, and yet not bright enough in their later stages of life.",
"Traditional solid state light sources used in traffic control signals are traditionally over driven initially so that when the light reduces later, the light output is still at a proper level meeting DOT requirements.",
"However, this overdrive significantly reduces the life of the LED device due to the increased, and unnecessary, drive power and associated heat of the device during the early term of use.",
"Thus, not only is the cost for operating the signal increased, but more importantly, the overall life of the device is significantly reduced by overdriving the solid state light source during the initial term of operation.",
"Still another problem with traditional light sources for traffic signals is detection of the light output using the traditional hand held meter.",
"Ambient light greatly affects the accurate detection of light output from the light source.",
"Therefore, it has been difficult in the past to precisely set the light output to a level that meets DOT standards, but which light source is not over driven to the point of providing more light than necessary, which as previously mentioned, increases temperature and degrades the useful life of the solid state device.",
"Still another problem in prior art traffic signals is that signal visibility needs to be controlled so only specific lanes of traffic are able to see the traffic light.",
"An example is when a left turn lane has a green light, and an adjacent lane is designated as a straight lane.",
"It is necessary for traffic in the left turn lane to see the green light.",
"The current visibility control mechanism is mechanical, typically implementing a set of baffles inserted into the light system to carefully block the generated light from the unintended lane.",
"The mechanical direction system is not very controllable because it is controlled in only one dimension, typically either up or down, or, either right or left, but not both.",
"Consequently, the light is undesirable often seen in the adjacent lane.",
"There is arisen a need for a better method to control the visibility range of a traffic signal.",
"Traditionally, old technology is typically replaced with new technology by simply disposing of the old technology traffic devices.",
"Since most cities don't have the budget to replace all traffic control devices when new ones come to market, they have traditionally taken the position of replacing only a portion of the cities devices at any given time, thereby increasing the inventory needed for the city.",
"Larger cities end up inventorying many different manufacture's traffic signals, some of which are not in production any longer.",
"The added cost is not only for storage of inventoried items, but also the overhead of taking all different types of equipment to a repair site, or cataloging the different inventoried items at different locations.",
"With respect to alignment systems for traffic lights, traditionally alignment traffic control devices provide that one person points the generated light beam in the desired direction from a bucket while above the intersection, while another person stands in the traffic lanes to determine if the light is aligned properly.",
"The person on the ground has to move over the entire field of view to check the light alignment.",
"If the light is masked off (such as a turn arrow), there are more alignment iterations.",
"There is desired a faster and more reliable method of aligning traffic signals.",
"Traffic lights also have a problem during darker conditions, i.e. at night or at dusk when the light is not well defined.",
"This causes a problem if the light has to be masked off for any reason, whereby light may overlap to areas that should be off.",
"This imprecise on/off boundary is called “ghosting.”",
"There is a need to find an improved way to define the light/dark boundary of the traffic light to reduce ghosting.",
"The ghosting is primarily caused by the angle the light hits on the “risers”",
"on a Fresnel lens.",
"A traffic light with a longer focal length reduces the angle, therefore decreasing the amount of ghosting.",
"Therefore, devices with shorter focal lengths have increased ghosting.",
"Another cause of ghosting is stray light from arrays of LED lights.",
"Typical LED designs have a rather large intensity peek, that is, a less uniform beam of light being generated from the array.",
"SUMMARY OF THE INVENTION The present invention achieves many technical advantages as an improved traffic control signal.",
"A solid state light source has many advantageous features including the ability to predict failure of the light source, as well as an extended life time by using an external heatsink having a solar shield facilitating ambient airflow therepast to sink heat away from an LED light array, hermetically sealing the array of LEDs with a glass-to-metal seal, and controlling the light output over time to prevent overdrive of the LED array.",
"Other features of the present invention include providing a constant output of light from a solid state light source by providing optical feedback of light and electronic filtering to accurately detect and discern generated light from ambient light.",
"Other advantages of the solid state light source include an electronically steerable light beam having the ability to steer light into two dimensions, insuring only the intended lane of traffic is able to visually perceive the beam of light.",
"In addition, the solid state light source is modularly upgradeable to allow upgrades of existing components, and the adaption of new components to keep the traffic signal state of the art.",
"An optical sight alignment mechanism is also provided with the light source allowing a technician at the light source to determine where a beam of light generated from the light array is directed, without requiring the assistance of an on ground technician.",
"Yet another feature of the present invention is an opto-electronic rolloff control for a light source reducing ghosting of a generated beam of light.",
"The solid state light of the present invention includes several new features, and several improved features, providing a state of the art solid state light source that overcomes the limitations of prior art traffic sources, including those with conventional solid state light sources.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 A and FIG. 2A is a front perspective view and rear perspective view, respectively, of a solid state light apparatus according to a first preferred embodiment of the present invention including an optical alignment eye piece;",
"FIG. 2 A and FIG. 2B is a front perspective view and a rear perspective view, respectively, of a second preferred embodiment having a solar louvered external air cooled heatsink;",
"FIG. 3 is a side sectional view of the apparatus shown in FIG. 1 illustrating the electronic and optical assembly and lens system comprising an array of LEDs directly mounted to a heatsink, directing light through a diffuser and through a Fresnel lens;",
"FIG. 4 is a perspective view of the electronic and optical assembly comprising the LED array, lense holder, light diffuser, power supply, main motherboard and daughterboard;",
"FIG. 5 is a side view of the assembly of FIG. 4 illustrating the array of LEDs being directly mounted to the heatsink, below respective lenses and disposed beneath a light diffuser, the heatsink for terminally dissipating generated heat;",
"FIG. 6 is a top view of the electronics assembly of FIG. 4;",
"FIG. 7 is a side view of the electronics assembly of FIG. 4;",
"FIG. 8 is a top view of the lens holder adapted to hold lenses for the array of LEDs;",
"FIG. 9 is a sectional view taken alone lines 9 — 9 in FIG. 8 illustrating a shoulder and side wall adapted to securely receive a respective lens for a LED mounted thereunder;",
"FIG. 10 is a top view of the heatsink comprised of a thermally conductive material and adapted to securingly receive each LED, the LED holder of FIG. 8, as well as the other componentry;",
"FIG. 11 is a side view of the light diffuser depicting its radius of curvature;",
"FIG. 12 is a top view of the light diffuser of FIG. 11 illustrating the mounting flanges thereof;",
"FIG. 13 is a top view of a Fresnel lens as shown in FIG. 3;",
"FIG. 14A is a view of a remote monitor displaying an image generated by a video camera in the light apparatus to facilitate electronic alignment of the LED light beam;",
"FIG. 14B is a perspective view of the lid of the apparatus shown in FIG. 1 having a grid overlay for use with the optical alignment system;",
"FIG. 15 is a perspective view of the optical alignment system eye piece adapted to connect to the rear of the light unit shown in FIG. 1;",
"FIG. 16 is a schematic diagram of the control circuitry disposed on the daughterboard and incorporating various features of the invention including control logic, as well as light detectors for sensing ambient light and reflected generated light from the light diffuser used to determine and control the light output from the solid state light;",
"FIG. 17 is an algorithm depicting the sensing of ambient light and backscattered light to selectably provide a constant output of light;",
"FIG. 18 a AND FIG. 18B are side sectional views of an alternative preferred embodiment including a heatsink with recesses, with the LED's wired in parallel and series, respectively;",
"FIG. 19 is an algorithm depicting generating information indicative of the light operation, function and prediction of when the said state apparatus will fail or provide output below acceptable light output;",
"FIGS. 20 and 21 illustrate operating characteristics of the LEDs as a function of PWM duty cycles and temperature as a function of generated output light;",
"FIG. 22 is a block diagram of a modular light apparatus having selectively interchangeable devices that are field replaceable;",
"FIG. 23 is a perspective view of a light guide having a light channel for each LED to direct the respective LED light to the diffuser;",
"FIG. 24 shows a top view of FIG. 23 of the light guide for use with the diffuser;",
"and FIG. 25 shows a side sectional view taken along line 24 — 24 in FIG. 3 illustrating a separate light guide cavity for each LED extending to the light diffuser.",
"DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIG. 1A, there is illustrated generally at 10 a front perspective view of a solid state lamp apparatus according to a first preferred embodiment of the present invention.",
"Light apparatus 10 is seen to comprise a trapezoidal shaped housing 12 , preferably comprised of plastic formed by a plastic molding injection techniques, and having adapted to the front thereof a pivoting lid 14 .",
"Lid 14 is seen to have a window 16 , as will be discussed shortly, permitting light generated from within housing 12 to be emitted as a light beam therethrough.",
"Lid 14 is selectively and securable attached to housing 12 via a hinge assemble 17 and secured via latch 18 which is juxtaposed with respect to a housing latch 19 , as shown.",
"Referring now to FIG. 1 B and FIG. 2B, there is illustrated a second preferred embodiment of the present invention at 32 similar to apparatus 10 , whereby a housing 33 includes a solar louver 34 as shown in FIG. 2 B. The solar louver 34 is secured to housing 33 and disposed over a external heatsink 20 which shields the external heatsink 20 from solar radiation while permitting outside airflow across the heatsink 20 and under the shield 34 , thereby significantly improving cooling efficiency as will be discussed more shortly.",
"Referring to FIG. 2A, there is shown light apparatus 10 of FIG. 1A having a rear removable back member 20 comprised of thermally conductive material and forming a heatsink for radiating heat generated by the internal solid state light source, to be discussed shortly.",
"Heatsink 20 is seen to have secured thereto a pair hinges 22 which are rotatably coupled to respective hinge members 23 which are securely attached and integral to the bottom of the housing 12 , as shown.",
"Heatsink 20 is further seen to include a pair of opposing upper latches 24 selectively securable to respective opposing latches 25 forming an integral portion of and secured to housing 12 .",
"By selectively disconnecting latches 24 from respective latches 25 , the entire rear heatsink 20 may be pivoted about members 23 to access the internal portion of housing 12 , as well as the light assembly secured to the front surface of heatsink 20 , as will be discussed shortly in regards to FIG. 3 .",
"Still referring to FIG. 2A, light apparatus 10 is further seen to include a rear eye piece 26 including a U-shaped bracket extending about heatsink 20 and secured to housing 12 by slidably locking into a pair of respective locking members 29 securely affixed to respective sidewalls of housing 12 .",
"Eye piece 26 is also seen to have a cylindrical optical sight member 28 formed at a central portion of, and extending rearward from, housing 12 to permit a user to optically view through apparatus 10 via optically aligned window 16 to determine the direction a light beam, and each LED, is directed, as will be described in more detail with reference to FIG. 14 and FIG. 15 .",
"Also shown is housing 12 having an upper opening 30 with a serrated collar centrally located within the top portion of housing 12 , and opposing opening 30 at the lower end thereof, as shown in FIG. 3 .",
"Openings 30 facilitate securing apparatus 10 to a pair of vertical posts allowing rotation laterally thereabout.",
"Referring now to FIG. 3, there is shown a detailed cross sectional view taken along line 3 — 3 in FIG. 1, illustrating a solid state light assembly 40 secured to rear heatsink 20 in such an arrangement as to facilitate the transfer of heat generated by light assembly 40 to heatsink 20 for the dissipation of heat to the ambient via heatsink 20 .",
"Solid state light assembly 40 is seen to comprise an array of light emitting diodes (LEDs) 42 aligned in a matrix, preferably comprising an 8×8 array of LEDs each capable of generating a light output of 1-3 lumens.",
"However, limitation to the number of LEDs or the light output of each is not to be inferred.",
"Each LED 42 is directly bonded to heatsink 20 within a respective light reflector comprising a recess defined therein.",
"Each LED 42 is hermetically sealed by a glass material sealingly diffused at a low temperature over the LED die 42 and the wire bond thereto, such as 8000 Angstroms of, SiO 2 or Si 3 N 4 material diffused using a semiconductor process.",
"The technical advantages of this glass to metal hermetic seal over plastic/epoxy seals is significantly a longer LED life due to protecting the LED die from oxygen, humidity and other contaminants.",
"If desired, for more light output, multiple LED dies 42 can be disposed in one reflector recess.",
"Each LED 42 is directly secured to, and in thermal contact arrangement with, heatsink 20 , whereby each LED is able to thermally dissipate heat via the bottom surface of the LED.",
"Interfaced between the planar rear surface of each LED 42 is a thin layer of heat conductive material 46 , such as a thin layer of epoxy or other suitable heat conductive material insuring that the entire rear surface of each LED 42 is in good thermal contact with rear heatsink 20 to efficiently thermally dissipate the heat generated by the LEDs.",
"Each LED connected electrically in parallel has its cathode electrically coupled to the heatsink 20 , and its Anode coupled to drive circuitry disposed on daughterboard 60 .",
"Alternatively, if each LED is electrically connected in series, the heatsink 20 preferably is comprised of an electrically non-conductive material such as ceramic.",
"Further shown in FIG. 3 is a main circuit board 48 secured to the front surface of heatsink 20 , and having a central opening for allowing LED to pass generated light therethrough.",
"LED holder 44 mates to the main circuit board 48 above and around the LED's 42 , and supports a lens 86 above each LED.",
"Also shown is a light diffuser 50 secured above the LEDs 42 by a plurality of standoffs 52 , and having a rear curved surface 54 spaced from and disposed above the LED solid state light source 40 , as shown.",
"Each lens 86 (FIG.",
"9) is adapted to ensure each LED 42 generates light which impinges the rear surface 54 having the same surface area.",
"Specifically, the lenses 86 at the center of the LED array have smaller radius of curvature than the lenses 86 covering the peripheral LEDs 42 .",
"The diffusing lenses 46 ensure each LED illuminates the same surface area of light diffuser 50 , thereby providing a homogeneous (uniform) light beam of constant intensity.",
"A daughter circuit board 60 is secured to one end of heatsink 20 and main circuit board 48 by a plurality of standoffs 62 , as shown.",
"At the other end thereof is a power supply 70 secured to the main circuit board 48 and adapted to provide the required drive current and drive voltage to the LEDs 42 comprising solid state light source 40 , as well as electronic circuitry disposed on daughterboard 60 , as will be discussed shortly in regards to the schematic diagram shown in FIG. 16 .",
"Light diffuser 50 uniformly diffuses light generated from LEDs 42 of solid state light source 40 to produce a homogeneous light beam directed toward window 16 .",
"Window 16 is seen to comprise a lens 70 , and a Fresnel lens 72 in direct contact with lens 70 and interposed between lens 70 and the interior of housing 12 and facing light diffuser 50 and solid state light source 40 .",
"Lid 14 is seen to have a collar defining a shoulder 76 securely engaging and holding both of the round lens 70 and 72 , as shown, and transparent sheet 73 having defined thereon grid 74 as will be discussed further shortly.",
"One of the lenses 70 or 72 are colored to produce a desired color used to control traffic including green, yellow, red, white and orange.",
"It has been found that with the external heatsink being exposed to the outside air the outside heatsink 20 cools the LED die temperature up to 50° C. over a device not having a external heatsink.",
"This is especially advantageous when the sun setting to the west late in the afternoon such as at an elevation of 10° or less, when the solar radiation directed in to the lenses and LEDs significantly increasing the operating temperature of the LED die for westerly facing signals.",
"The external heatsink 20 prevents extreme internal operating air and die temperatures and prevents thermal runaway of the electronics therein.",
"Referring now to FIG. 4, there is shown the electronic and optic assembly comprising of solid state light source 40 , light diffuser 50 , main circuit board 48 , daughter board 60 , and power supply 70 .",
"As illustrated, the electronic circuitry on daughter board 60 is elevated above the main board 48 , whereby standoffs 62 are comprised of thermally nonconductive material.",
"Referring to FIG. 5, there is shown a side view of the assembly of FIG. 4 illustrating the light diffuser 50 being axially centered and disposed above the solid state LED array 40 .",
"Diffuser 50 , in combination with the varying diameter lenses 86 , facilitates light generated from the LEDs 42 to be uniformly disbursed and have uniform intensity and directed upwardly as a light beam toward the lens 70 and 72 , as shown in FIG. 3 .",
"Referring now to FIG. 6, there is shown a top view of the assembly shown in FIG. 4, whereby FIG. 7 illustrates a side view of the same.",
"Referring now to FIG. 8, there is shown a top view of the lens holder 44 comprising a plurality of openings 80 each adapted to receive one of the LED lenses 86 hermetically sealed to and bonded thereover.",
"Advantageously, the glass to metal hermetic seal has been found in this solid state light application to provide excellent thermal conductivity and hermetic sealing characteristics.",
"Each opening 80 is shown to be defined in a tight pack arrangement about the plurality of LEDs 42 .",
"As previously mentioned, the lenses 86 at the center of the array, shown at 81 , have a smaller curvature diameter than the lenses 86 over the perimeter LEDs 42 to increase light dispersion and ensure uniform light intensity impinging diffuser 50 .",
"Referring to FIG. 9, there is shown a cross section taken alone line 9 — 9 in FIG. 8 illustrating each opening 80 having an annular shoulder 82 and a lateral sidewall 84 defined so that each cylindrical lens 86 is securely disposed within opening 80 above a respective LED 42 .",
"Each LED 42 is preferably mounted to heatsink 20 using a thermally conductive adhesive material such as epoxy to ensure there is no air gaps between the LED 42 and the heatsink 20 .",
"The present invention derives technical advantages by facilitating the efficient transfer of heat from LED 42 to the heatsink 20 .",
"Referring now to FIG. 10, there is shown a top view of the main circuit board 48 having a plurality of openings 90 facilitating the attachment of standoffs 62 securing the daughter board above an end region 92 .",
"The power supply 48 is adapted to be secured above region 94 and secured via fasteners disposed through respective openings 96 at each corner thereof.",
"Center region 98 is adapted to receive and have secured thereagainst in a thermal conductive relationship the LED holder 42 with the thermally conductive material 46 being disposed thereupon.",
"The thermally conductive material preferably comprises of epoxy, having dimensions of, for instance, 0.05 inches.",
"A large opening 99 facilitates the attachment of LED's 42 to the heatsink 20 , and such that light from the LEDs 42 is directed to the light diffuser 50 .",
"Referring now to FIG. 11, there is shown a side elevational view of diffuser 50 having a lower concave surface 54 , preferably having a radius A of about 2.4 inches, with the overall diameter B of the diffuser including a flange 55 being about 6 inches.",
"The depth of the rear surface 52 is about 1.85 inches as shown as dimension C. Referring to FIG. 12, there is shown a top view of the diffuser 50 including the flange 56 and a plurality of openings 58 in the flange 56 for facilitating the attachment of standoffs 52 to and between diffuser 50 and the heatsink 20 , shown in FIG. 4 .",
"Referring now to FIG. 13 there is shown the Fresnel lens 72 , preferably having a diameter D of about 12.2 inches.",
"However, limitation to this dimension is not to be inferred, but rather, is shown for purposes of the preferred embodiment of the present invention.",
"The Fresnel lens 72 has a predetermined thickness, preferably in the range of about {fraction (1/16)} inches.",
"This lens is typically fabricated by being cut from a commercially available Fresnel lens.",
"Referring now back to FIG. 1 A and FIG. 1B, there is shown generally at 56 a video camera oriented to view forward of the front face of solid state lamp 10 and 30 , respectively.",
"The view of this video camera 56 is precisionally aligned to view along and generally parallel to the central longitudinal axis shown at 58 that the beam of light generated by the internal LED array is oriented.",
"Specifically, at large distances, such as greater than 20 feet, the video camera 56 generates an image having a center of the image generally aligned with the center of the light beam directed down the center axis 58 .",
"This allows the field technician to remotely electronically align the orientation of the light beam referencing this video image.",
"For instance, in one preferred embodiment the control electronics 60 has software generating and overlaying a grid along with the video image for display at a remote display terminal, such as a LCD or CRT display shown at 59 in FIG. 14 A. This video image is transmitted electronically either by wire using a modem, or by wireless communication using a transmitter allowing the field technician on the ground to ascertain that portion of the road that is in the field of view of the generated light beam.",
"By referencing this displayed image, the field technician can program which LEDs 42 should be electronically turned on, with the other LEDs 42 remaining off, such that the generated light beam will be focused by the associated optics including the Fresnel lens 72 , to the proper lane of traffic.",
"Thus, on the ground, the field technician can electronically direct the generated light beam from the LED arrays, by referencing the video image, to the proper location on the ground without mechanical adjustment at the light source, such as by an operator situated in a DOT bucket.",
"For instance, if it is intended that the objects viewable and associated with the upper four windows defined by the grid should be illuminated, such as those objects viewable through the windows labeled as W in FIG. 14A, the LEDs 42 associated with the respective windows “W”",
"will be turned on, with the rest of the LEDs 46 associated with the other windows being turned off.",
"Preferably, there is one LED 46 associated with each window defined by the grid.",
"Alternatively, a transparent sheet 73 having a grid 74 defining windows 78 can be laid over the display surface of the remote monitor 59 whereby each window 78 corresponds with one LED.",
"For instance, there may be 64 windows associated with the 64 LEDs of the LED array.",
"Individual control of the respective LEDs is discussed hereafter in reference to FIG. 14 A. The video camera 56 , such as a CCD camera or a CMCS camera, is physically aligned alone the central axis 58 , such that at extended distances the viewing area of the camera 56 is generally along the axis 58 and thus is optically aligned with regards to the normal axis 58 for purposes of optical alignment.",
"Referring now to FIG. 14B, there is illustrated the lid 14 , the hinge members 17 , and the respective latches 18 .",
"Holder 14 is seen to further have an annular flange member 70 defining a side wall about window 16 , as shown.",
"Further shown the transparent sheet 73 and grid 74 comprising of thin line markings defined over openings 16 defining windows 78 .",
"The sheet can be selectively placed over window 16 for alignment, and which is removable therefrom after alignment.",
"Each window 78 is precisionally aligned with and corresponds to one sixty four (64) LEDs 42 .",
"Indicia 79 is provided to label the windows 78 , with the column markings preferably being alphanumeric, and the columns being numeric.",
"The windows 78 are viable through optical sight member 28 , via an opening in heatsink 20 .",
"The objects viewed in each window 78 are illuminated substantially by the respective LED 42 , allowing a technician to precisionally orient the apparatus 10 so that the desired LEDs 42 are oriented to direct light along a desired path and be viewed in a desired traffic lane.",
"The sight member 28 may be provided with cross hairs to provide increased resolution in combination with the grid 74 for alignment.",
"Moreover, electronic circuitry 100 on daughterboard 60 can drive only selected LEDs 42 or selected 4×4 portions of array 40 , such as a total of 16 LED's 42 being driven at any one time.",
"Since different LED's have lenses 86 with different radius of curvature different thicknesses, or even comprised of different materials, the overall light beam can be electronically steered in about a 15° cone of light relative to a central axis defined by window 16 and normal to the array center axis.",
"For instance, driving the lower left 4×4 array of LEDs 42 , with the other LEDs off, in combination with the diffuser 50 and lens 70 and 72 , creates a light beam +7.5 degrees above a horizontal axis normal to the center of the 8×8 array of LEDs 42 , and +7.5 degrees right of a vertical axis.",
"Likewise, driving the upper right 4×4 array of LEDs 42 would create a light beam +10 degrees off the horizontal axis and +7.5 degrees to the right of a normalized vertical axis and −7.5 degrees below a vertical axis.",
"The radius of curvature of the center lenses 86 may be, for instance, half that of the peripheral lenses 86 .",
"A beam steerable ±7.5 degrees in 1-2 degree increments is selectable.",
"This feature is particularly useful when masking the opening 16 , such as to create a turn arrow.",
"This filter reduces ghosting or roll-off, which is stray light being directed in an unintended direction and viewable from an unintended traffic lane.",
"The electronically controlled LED array provides several technical advantages including no light is blocked, but rather is electronically steered to control a beam direction.",
"Low power LEDs are used, whereby the small number of the LEDs “on”",
"(i.e. 4 of 64) consume a total power about 1-2 watts, as opposed to an incandescent prior art bulb consuming 150 watts or a flood 15 watt LED which are masked or lowered.",
"The present invention reduces power and heat generated thereby.",
"Referring now to FIG. 15, there is shown a perspective view of the eye piece 26 as well as the optical sight member 28 , as shown in FIG. 1, the center axis of optical sight member 28 is oriented along the center of the 8×8 LED array.",
"Referring now to FIG. 16, there is shown at 100 a schematic diagram of the circuitry controlling light apparatus 10 .",
"Circuit 10 is formed on the daughter board 60 , and is electrically connected to the LED solid state light source 40 , and selectively drives each of the individual LEDs 42 comprising the array.",
"Depicted in FIG. 16 is a complex programmable logic device (CPLD) shown as U 1 .",
"CPLD U 1 is preferably an off-the-shelf component such as provided by Maxim Corporation, however, limitation to this specific part is not to be inferred.",
"For instance, discrete logic could be provided in place of CPLD U 1 to provide the functions as is described here, with it being understood that a CPLD is the preferred embodiment is of the present invention.",
"CPLD U 1 has a plurality of interface pins, and this embodiment, shown to have a total of 144 connection pins.",
"Each of these pin are numbered and shown to be connected to the respective circuitry as will now be described.",
"Shown generally at 102 is a clock circuit providing a clock signal on line 104 to pin 125 of the CPLD U 1 .",
"Preferably, this clock signal is a square wave provided at a frequency of 32.768 KHz.",
"Clock circuit 102 is seen to include a crystal oscillator 106 coupled to an operational amplifier U 5 and includes associated trim components including capacitors and resistors, and is seen to be connected to a first power supply having a voltage of about 3.3 volts.",
"Still referring to FIG. 16, there is shown at 110 a power up clear circuit comprised of an operational amplifier shown at U 6 preferably having the non-inverting output coupled to pin 127 of CPLD U 1 .",
"The inverting input is seen to be coupled between a pair of resistors providing a voltage divide circuit, providing approximately a 2.425 volt reference signal based on a power supply of 4.85 volts being provided to the positive rail of the voltage divide network.",
"The inverting input is preferably coupled to the 4.85 voltage reference via a current limiting resistor, as shown.",
"As shown at 112 , an operational amplifier U 9 is shown to have its non-inverting output connected to pin 109 of CPLD U 1 .",
"Operational amplifier U 9 provides a power down function.",
"Referring now to circuit 120 , there is shown a light intensity detection circuit detecting ambient light intensity and comprising of a photodiode identified as PD 1 .",
"An operational amplifier depicted as U 7 is seen to have its non-inverting input coupled to input pin 99 of CPLD U 1 .",
"The non-inverting input of amplifier U 7 is connected to the anode of photodiode PD 1 , which photodiode has its cathode connected via a capacitor to the second power supply having a voltage of about 4.85 volts.",
"The non-inverting input of amplifier U 7 is also connected via a diode Q 1 , depicted as a transistor with its emitter tied to its base and provided with a current limiting resistor.",
"The inverting input of amplifier U 7 is connected via a resistor to input 108 of CPLD U 1 .",
"Shown at 122 is a similar light detection circuit detecting the intensity of backscattered light from Fresnel lens 72 as shown at 124 in FIG. 3, and based around a second photodiode PD 2 , including an amplifier U 10 and a diode Q 2 .",
"The non-inverting output of amplifier U 10 , forming a buffer, is connected to pin 82 of CPLD U 1 .",
"An LED drive connector is shown at 130 serially interfaces LED drive signal data to drive circuitry of the LEDs 42 .",
"(Inventors please describe the additional drive circuit schematic).",
"Shown at 140 is another connector adapted to interface control signals from CPLD U 1 to an initiation control circuit for the LED's.",
"Each of the LEDs 42 is individually controlled by CPLD U 1 whereby the intensity of each LED 42 is controlled by the CPLD U 1 selectively controlling a drive current thereto, a drive voltage, or adjusting a duty cycle of a pulse width modulation (PWM) drive signal, and as a function of sensed optical feedback signals derived from the photodiodes as will be described shortly here, in reference to FIG. 17 .",
"Referring to FIG. 17 in view of FIG. 3, there is illustrated how light generated by solid state LED array 40 is diffused by diffuser 50 , and a small portion 124 of which is back-scattered by the inner surface of Fresnel lens 72 back toward the surface of daughter board 60 .",
"The back-scattered diffused light 124 is sensed by photodiodes PD 2 , shown in FIG. 16 .",
"The intensity of this back-scattered light 124 is measured by circuit 122 and provided to CPLD U 1 .",
"CPLD U 1 measures the intensity of the ambient light via circuit 120 using photodiode PD 1 .",
"The light generated by LED's 42 is preferably distinguished by CPLD U 1 by strobing the LEDs 42 using pulse width modulation (PWM) to discern ambient light (not pulsed) from the light generated by LEDs 42 .",
"CPLD U 1 individually controls the drive current, drive voltage, or PWM duty cycle to each of the respective LEDs 42 as a function of the light detected by circuits 120 and 122 .",
"For instance, it is expected that between 3 and 4% of the light generated by LED array 40 will back-scatter back from the fresnel lens 72 toward to the circuitry 100 disposed on daughter board 60 for detection.",
"By normalizing the expected reflected light to be detected by photodiodes PD 2 in circuit 122 , for a given intensity of light to be emitted by LED array 40 through window 16 of lid 14 , optical feedback is used to ensure an appropriate light output, and a constant light output from apparatus 10 .",
"For instance, if the sensed back-scattered light, depicted as rays 124 in FIG. 3, is detected by photodiodes PD 2 to fall about 2.5% from the normalized expected light to be sensed by photodiodes PD 2 , such as due to age of the LEDs 42 , CPLD U 1 responsively increases the drive current to the LEDs a predicted percentage, until the back-scattered light as detected by photodiodes PD 2 is detected to be the normalized sensed light intensity.",
"Thus, as the light output of LEDs 42 degrade over time, which is typical with LEDs, circuit 100 compensates for such degradation of light output, as well as for the failure of any individual LED to ensure that light generated by array 40 and transmitted through window 16 meets Department of Transportation (DOT) standards, such as a 44 point test.",
"This optical feedback compensation technique is also advantageous to compensate for the temporary light output reduction when LEDs become heated, such as during day operation, known as the recoverable light, which recoverable light also varies over temperatures as well.",
"Permanent light loss is over time of operation due to degradation of the chemical composition of the LED semiconductor material.",
"Preferably, each of the LEDs is driven by a pulse width modulated (PWM) drive signal, providing current during a predetermined portion of the duty cycle, such as for instance, 50%.",
"As the LEDs age and decrease in light output intensity, and also during a day due to daily temperature variations, the duty cycle may be responsively, slowly and continuously increased or adjusted such that the duty cycle is appropriate until the intensity of detected light by photodiodes PD 2 is detected to be the normalized detected light.",
"When the light sensed by photodides PD 2 are determined by controller 60 to fall below a predetermined threshold indicative of the overall light output being below DOT standards, a notification signal is generated by the CPLD U 1 which may be electronically generated and transmitted by an RF modem, for instance, to a remote operator allowing the dispatch of service personnel to service the light.",
"Alternatively, the apparatus 10 can responsively be shut down entirely.",
"Referring now to FIG. 18 A and FIG. 18B, there is shown an alternative preferred embodiment of the present invention including a heatsink 200 machined or stamped to have an array of reflectors 202 .",
"Each recess 202 is defined by outwardly tapered sidewalls 204 and a base surface 208 , each recess 202 having mounted thereon a respective LED 42 .",
"A lens array having a separate lens 210 for each LED 42 is secured to the heatsink 200 over each recess 202 , eliminating the need for a lens holder.",
"The tapered sidewalls 206 serve as light reflectors to direct generated light through the respective lens 210 at an appropriate angle to direct the associated light to the diffuser 50 having the same surface area of illumination for each LED 42 .",
"In one embodiment, as shown in FIG. 18A, LEDs 42 are electrically connected in parallel.",
"The cathode of each LED 42 is electrically coupled to the electrically conductive heatsink 200 , with a respective lead 212 from the anode being coupled to drive circuitry 216 disposed as a thin film PCB 45 adhered to the surface of the heatsink 200 , or defined on the daughterboard 60 as desired.",
"Alternatively, as shown in FIG. 18B, each of the LED's may be electrically connected in series, such as in groups of three, and disposed on an electrically non-conductive thermally conductive material 43 such as ceramic, diamond, SiN or other suitable materials.",
"In a further embodiment, the electrically non-conductive thermally conductive material may be formed in a single process by using a semiconductor process, such as diffusing a thin layer of material in a vacuum chamber, such as 8000 Angstroms of SiN, which a further step of defining electrically conductive circuit traces 45 on this thin layer.",
"FIG. 19 shows an algorithm controller 60 applies for predicting when the solid state light apparatus will fail, and when the solid state light apparatus will produce a beam of light having an intensity below a predetermined minimum intensity such as that established by the DOT.",
"Referring to the graphs in FIG. 20 and 21, the known operating characteristics of the particular LEDs produced by the LED manufacture are illustrated and stored in memory, allowing the controller 60 to predict when the LED is about the fail.",
"Knowing the LED drive current operating temperature, and total time the LED as been on, the controller 60 determines which operating curve in FIG. 20 and FIG. 21 applies to the current operating conditions, and determines the time until the LED will degrade to a performance level below spec, i.e. below DOT minimum intensity requirements.",
"FIG. 22 depicts a block diagram of the modular solid state traffic light device.",
"The modular field-replaceable devices are each adapted to selectively interface with the control logic daughterboard 60 via a suitable mating connector set.",
"Each of these modular field replacable devices 216 are preferably embodied as a separate card, with possibly one or more feature on a single field replacable card, adapted to attach to daughterboard 60 by sliding into or bolting to the daughterboard 60 .",
"The devices can be selected from, alone or in combination with, a pre-emption device, a chemical sniffer, a video loop detector, an adaptive control device, a red light running (RLR) device, and an in-car telematic device, infrared sensors to sense people and vehicles under fog, rain, smode and other adverse visual conditions, automobile emission monitoring, various communication links, electronically steerable beam, exhaust emission violations detection, power supply predictive failure analysis, or other suitable traffic devices.",
"The solid state light apparatus 10 of the present invention has numerous technical advantages, including the ability to sink heat generated from the LED array to thereby reduce the operating temperature of the LEDs and increase the useful life thereof.",
"Moreover, the control circuitry driving the LEDs includes optical feedback for detecting a portion of the back-scattered light from the LED array, as well as the intensity of the ambient light, facilitating controlling the individual drive currents, drive voltages, or increasing the duty cycles of the drive voltage, such that the overall light intensity emitted by the LED array 40 is constant, and meets DOT requirements.",
"The apparatus is modular in that individual sections can be replaced at a modular level as upgrades become available, and to facilitate easy repair.",
"With regards to circuitry 100 , CPLD U 1 is securable within a respective socket, and can be replaced or reprogrammed as improvements to the logic become available.",
"Other advantages include programming CPLD U 1 such that each of the LEDs 42 comprising array 40 can have different drive currents or drive voltages to provide an overall beam of light having beam characteristics with predetermined and preferably parameters.",
"For instance, the beam can be selectively directed into two directions by driving only portions of the LED array in combination with lens 70 and 72 .",
"One portion of the beam may be selected to be more intense than other portions of the beam, and selectively directed off axis from a central axis of the LED array 40 using the optics and the electronic beam steering driving arrangement.",
"Referring now to FIG. 23, there is shown at 220 a light guide device having a concave upper surface and a plurality of vertical light guides shown at 222 .",
"One light guide 222 is provided for and positioned over each LED 42 , which light guide 222 upwardly directs the light generated by the respective LED 42 to impinge the outer surface of the diffuser 54 .",
"The guides 222 taper outwardly at a top end thereof, as shown in FIG. 24 and FIG. 25, such that the area at the top of each light guide 222 is identical.",
"Thus each LED 42 illuminates an equal surface area of the light diffuser 54 , thereby providing a uniform intensity light beam from light diffuser 54 .",
"A thin membrane 224 defines the light guide, like a honeycomb, and tapers outwardly to a point edge at the top of the device 220 .",
"These point edges are separated by a small vertical distance D shown in FIG. 25, such as 1 mm, from the above diffuser 54 to ensure uniform lighting at the transistion edges of the light guides 222 while preventing bleeding of light laterally between guides, and to prevent light roll-off by generating a homogeneous beam of light.",
"Vertical recesses 226 permit standoffs 52 extending along the sides of device 220 (see FIG. 3) to support the peripheral edge of the diffuser 54 .",
"While the invention has been described in conjunction with preferred embodiments, it should be understood that modifications will become apparent to those of ordinary skill in the art and that such modifications are therein to be included within the scope of the invention and the following claims."
] |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a semiconductor structure and a method for manufacturing the same, and particularly relates to a semiconductor having a dielectric layer applied on a gate of a transistor, and a high dielectric-coefficient, and a manufacturing method for the semiconductor.
[0003] 2. Description of the Related Art
[0004] In the semiconductor process, the function of dielectric layer is to act as an insulating material, such as SiO2 or SiN, for insulating from electrical signals between a conducting layer and a conducting wire. Moreover, it is know that the dielectric layers such as HfO and Si x N x are going to be applied to transistor gates in the future. Hence an atomic layer deposition method will be the main technology used to form a dielectric thin film. However, although forming Si x N x increases the stability of the dielectric thin film structure, the dielectric constant k is decreased. Moreover, in the atomic layer deposition technology, high quality HfSiO needs to be grown in an environment that is full of oxygen. In other words, HfSiO needs to be grown on an oxide layer. Furthermore, when the thickness of the oxide layer is about 5˜10 Å, it becomes an impediment to achieving high dielectric constants and low EOTs (Equivalent Oxide Thickness). Hence, it is vital for micro transistor technology that the thickness of the dielectric layer is reduced in the future.
[0005] In The Journal of Applied Physics Hyoung Kim et al published “Engineering chemically abrupt high-k metal oxide/Silicon interfaces using an oxygen-gettering metal overlayer” (Vol. 96 No. 6, page 3467-3472, 2004). The article discussed a Ti layer with HfO2 grown on it to absorb oxygen atoms for removing a dielectric layer. However, when the Ti:O is removed, the HfO 2 will be damaged in the removal process. Moreover, the Ti layer is formed on the HfO2 by PVD (Physical Vapor Deposition). Hence the HfO2 film will be harmed by the high power particles produced from the PVD. Furthermore, because there is a predetermined distance between the Ti layer and the HfO 2 layer, the absorbing efficiency of the Ti layer is decreased when the Ti layer absorbs the oxygen atoms.
SUMMARY OF THE INVENTION
[0006] The present invention provides a semiconductor structure and method for manufacturing the same. The semiconductor structure reduces the thickness of a dielectric layer thereof. Moreover, the present invention is adapted to a future transistor manufacturing process, and can certainly integrate PMOS together with NMOS.
[0007] In order to achieve the above objects, a semiconductor structure and a method for manufacturing the same is disclosed. Particularly, the present invention relates to a semiconductor having a dielectric layer applied on a gate of a transistor, and a high dielectric-coefficient, and a manufacturing method for the semiconductor. Ti is formed on the HfO 2 for absorbing oxygen atoms from the dielectric layer so as to reduce its thickness, and even to a point where it disappears completely. However, any TiO 2 grown on the layer of the Ti can advance the growing of the following HfO 2 . Simultaneously, the dielectric constant of TiO 2 is about 50, which enhances the dielectric constant for the dielectric layer of the gate substantially. In conclusion, Ti is used to absorb the oxygen atoms so as to reduce their thickness and increase the dielectric constant, and to further reduce EOT. Moreover, TiO 2 is formed and the dielectric constant is increased as well after a heating process. Accordingly, leakage can be avoided in the TiO 2 . Consequently, the present invention enhances the application of high-k gate dielectric with high electric constant, and continuously reduces the EOT.
[0008] A first aspect of the present invention is a semiconductor structure. The semiconductor structure comprises a substrate, a dielectric layer unit and a conducting layer. The dielectric layer unit is formed on the substrate, and the dielectric layer includes at least a metal oxide layer and a metal layer stacked on each other. The conducting layer is formed on the dielectric layer unit.
[0009] A second aspect of the present invention is a method for manufacturing a semiconductor structure. The method comprises: providing a substrate; forming a dielectric layer unit on the substrate, wherein the dielectric layer includes at least a metal oxide layer and a metal layer stacked on each other; and forming a conducting layer on the dielectric layer unit.
[0010] Moreover, in the first and second aspects, the metal oxide layer comprises at least a first metal oxide layer and a second metal oxide layer. The metal layer comprises at least a first metal layer. The first metal layer, the first metal oxide layer and the second metal oxide layer are stacked sequentially to form the dielectric layer unit.
[0011] Furthermore, in the first and second aspects, the metal oxide layer comprises at least a first metal oxide layer, a second metal oxide layer and a third metal oxide layer. The metal layer comprises at least a second metal layer. The first metal oxide layer, the second metal layer, the second metal oxide layer and the third metal oxide layer are stacked sequentially to form the dielectric layer unit.
[0012] A third aspect of the present invention is a method for manufacturing a semiconductor structure. The method comprises: providing a substrate; forming a chemical oxide layer on the substrate; forming a first metal oxide layer on the chemical oxide layer; forming a first metal layer on the first metal oxide layer; forming a second metal layer on the first metal layer; forming a second metal oxide layer on the second metal layer; and forming a conducting layer on the second metal oxide layer.
[0013] A fourth aspect of the present invention is a semiconductor structure. The semiconductor structure comprises a substrate, a chemical oxide layer formed on the substrate, a first metal oxide layer formed on the chemical oxide layer, a first metal layer formed on the first metal oxide layer, a second metal layer formed on the first metal layer, a second metal oxide layer formed on the second metal layer, and a conducting layer formed on the second metal oxide layer.
[0014] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. Other advantages and features of the invention will be apparent from the following description, drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which:
[0016] FIG. 1 is a schematic, cross-sectional view of a semiconductor structure according to the first embodiment of the present invention;
[0017] FIG. 2 is a schematic, cross-sectional view of a semiconductor structure according to the second embodiment of the present invention;
[0018] FIG. 3 is a schematic, cross-sectional view of a semiconductor structure according to the third embodiment of the present invention;
[0019] FIG. 4 is a schematic, cross-sectional view of a semiconductor structure according to the fourth embodiment of the present invention;
[0020] FIG. 5 is a flowchart of a method for manufacturing a semiconductor structure according to the first embodiment of the present invention;
[0021] FIG. 6 is a flowchart of a method for manufacturing a semiconductor structure according to the second embodiment of the present invention;
[0022] FIG. 7 is a flowchart of a method for manufacturing a semiconductor structure according to the third embodiment of the present invention; and
[0023] FIG. 8 is a flowchart of a method for manufacturing a semiconductor structure according to the fourth embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0024] FIG. 1 shows a schematic, cross-sectional view of a semiconductor structure according to the first embodiment of the present invention. The present invention provides a semiconductor structure, comprising a substrate 1 , a dielectric layer unit 2 and a conducting layer 3 .
[0025] The substrate 1 can be a Si substrate that has a SiO 2 formed thereon. The dielectric layer unit 2 is formed on the substrate 1 , and the dielectric layer 2 includes at least a metal oxide layer 20 and a metal layer 21 stacked upon each other. The conducting layer 3 is formed on the dielectric layer unit 2 , and the conducting layer 3 can be TiN.
[0026] Moreover, the metal oxide layer 20 can be HfO 2 , HfSiO, HfSiON or TiO 2 . The thickness of both the HfO 2 and the HfSiO can be between 0.1˜3 nm or 0.1˜5 nm, the thickness of the HfSiON can be between 0.1˜3 nm, and the thickness of the TiO 2 can be between 0.1˜2 nm. The metal layer 21 can be Ti, and the thickness of the Ti can be between 0.1˜2 nm. However, both the thickness and material of the metal oxide layer or the metal layer should not be used to limit the present invention.
[0027] FIG. 2 shows a schematic, cross-sectional view of a semiconductor structure according to the second embodiment of the present invention. The present invention provides a semiconductor structure, comprising a substrate 1 , a dielectric layer unit 4 , and a conducting layer 3 .
[0028] The second embodiment differs from the first embodiment in that the dielectric layer unit 4 has a first metal layer 40 , a first metal oxide layer 41 , and a second metal oxide layer 42 stacked sequentially. The first metal layer 40 can be Ti, and the thickness of the Ti is between 0.1˜2 nm. Both the first metal oxide layer 41 and the second metal oxide layer 42 can be HfO 2 , HfSiO, HfSiON, or TiO 2 . The thickness of the HfO 2 , HfSiO, HfSiON, or TiO 2 are all between 0.1˜3 nm or 0.1˜5 nm. Moreover, the total thickness of both the first metal layer and the first metal oxide layer can be between 0.1˜2 nm. However, both the thickness and material of the metal oxide layer or the metal layer should not be used to limit the present invention.
[0029] FIG. 3 shows a schematic, cross-sectional view of a semiconductor structure according to the third embodiment of the present invention. The present invention provides a semiconductor structure, comprising a substrate 1 , a dielectric layer unit 5 , and a conducting layer 3 .
[0030] The third embodiment differs from the first and second embodiments in that the dielectric layer unit 5 has a first metal oxide layer 50 , a second metal layer 51 , a second metal oxide layer 52 , and a third metal oxide layer 53 stacked sequentially. The second metal layer can be Ti, and the thickness of the second metal layer can be between 0.1˜2 nm. The first metal oxide layer 50 can be HfO 2 , HfSiO or HfSiON, and the thickness of the first metal oxide layer 50 can be between 0.1˜3 nm or 0.1˜5 nm. The second metal oxide layer 52 can be TiO 2 . The third metal oxide layer 53 can be HfO 2 , HfSiO or HfSiON, and the thickness of the first metal oxide layer 53 can be between 0.1˜3 nm or 0.1˜5 nm. However, both the thickness and material of the metal oxide layer or the metal layer should not be used to limit the present invention.
[0031] FIG. 4 shows a schematic, cross-sectional view of a semiconductor structure according to the fourth embodiment of the present invention. The present invention provides a semiconductor structure comprising a substrate 1 , a chemical oxide layer 6 , a first metal oxide layer 70 , a first metal layer 71 , a second metal layer 72 , a second metal oxide layer 73 , and a conducting layer 3 .
[0032] The chemical oxide layer 6 is formed on the substrate 1 . The first metal oxide layer 70 is formed on the chemical oxide layer 6 . The first metal layer 71 is formed on the first metal oxide layer 70 . The second metal layer 72 is formed on the first metal layer 71 . The second metal oxide layer 73 is formed on the second metal layer 72 . The conducting layer 3 is formed on the second metal oxide layer 73 . Hence the first metal oxide layer 70 , the first metal layer 71 , the second metal layer 72 , and the second metal oxide layer 73 can be stacked sequentially to form a dielectric layer unit 7 .
[0033] Moreover, both the first metal oxide layer 70 and the second metal oxide layer 73 can be HfO 2 , HfSiO, HfSiON, or TiO 2 , and their thickness can be between 0.1˜3 nm or 0.1˜5 nm. Both the first metal layer 71 and the second metal layer 72 can be Ti, and its thickness can be between 0.1˜2 nm. Furthermore, as in the first embodiment, the substrate 1 can be a Si substrate that has a SiO 2 formed thereon.
[0034] FIG. 5 shows a flowchart of a method for manufacturing a semiconductor structure according to the first embodiment of the present invention. The present invention provides a method for manufacturing a semiconductor structure, comprising: providing a substrate 1 (S 100 ); forming a metal oxide layer 20 on the substrate 1 (S 102 ); and forming a metal layer 21 on the metal oxide layer 20 (S 104 ). Hence the metal oxide layer 20 and the metal layer 21 are stacked upon each other to form a dielectric layer unit 2 . Next, the method comprises forming a conducting layer 3 on the metal layer 21 (S 106 ). Moreover, both the dielectric layer unit 2 and the conducting layer 3 are formed by a LTCVD (Low Temperature Chemical Vapor Deposition) that is an ALD (Atomic Layer Deposition) device.
[0035] Furthermore, after the step S 106 , the method further comprises: performing annealing to form a stacked gate (S 108 ); performing S/D (Source/Drain) annealing upon the stacked gate (S 110 ); and performing forming gas annealing (S 112 ). In addition, during the step S 110 and the step S 112 , oxygen is doped into Ti to from TiO 2 .
[0036] FIG. 6 shows a flowchart of a method for manufacturing a semiconductor structure according to the second embodiment of the present invention. The present invention provides a method for manufacturing a semiconductor structure, comprising: providing a substrate 1 (S 200 ); forming a first metal layer 40 on the substrate 1 (S 202 ); forming a first metal oxide layer 41 on the first metal layer 40 (S 204 ); and forming a second metal oxide layer 42 on the first metal oxide layer 41 (S 206 ). Hence the first metal layer 40 , the first metal oxide layer 41 and the second metal oxide layer 42 are stacked sequentially to form the dielectric layer unit 4 . Next, the method comprises forming a conducting layer 3 on the second metal oxide layer 42 (S 208 ). Moreover, both the dielectric layer unit 4 and the conducting layer 3 are formed by a LTCVD (Low Temperature Chemical Vapor Deposition) that is an ALD (Atomic Layer Deposition) device.
[0037] Furthermore, after the step S 208 , the method further comprises: performing annealing to form a stacked gate (S 210 ); performing S/D (Source/Drain) annealing upon the stacked gate (S 212 ); and performing forming gas annealing (S 214 ). In addition, during the step S 212 and the step S 214 , oxygen is doped into Ti to from TiO 2 .
[0038] FIG. 7 shows a flowchart of a method for manufacturing a semiconductor structure according to the third embodiment of the present invention. The present invention provides a method for manufacturing a semiconductor structure, comprising: providing a substrate 1 (S 300 ); forming a first metal oxide layer 50 on the substrate 1 (S 302 ); forming a second metal layer 51 on the first metal oxide layer 50 (S 304 ); forming a second metal oxide layer 52 on the second metal layer 51 (S 306 ); and forming a third metal oxide layer 53 on the second metal oxide layer 52 (S 308 ). Hence the first metal oxide layer 50 , the second metal layer 51 , the second metal oxide layer 52 and the third metal oxide layer 53 are stacked sequentially to form the dielectric layer unit 5 . Next, the method comprises forming a conducting layer 3 on the third metal oxide layer 53 (S 310 ). Moreover, both the dielectric layer unit 5 and the conducting layer 3 are formed by a LTCVD (Low Temperature Chemical Vapor Deposition) that is an ALD (Atomic Layer Deposition) device.
[0039] Furthermore, after the step S 310 , the method further comprises: performing annealing to form a stacked gate (S 312 ); performing S/D (Source/Drain) annealing upon the stacked gate (S 314 ); and performing forming gas annealing (S 316 ). In addition, during the step S 314 and the step S 316 , oxygen is doped into Ti to from TiO 2 .
[0040] FIG. 8 shows a flowchart of a method for manufacturing a semiconductor structure according to the fourth embodiment of the present invention. The present invention provides a method for manufacturing a semiconductor structure, comprising: providing a substrate 1 (S 400 ); forming a chemical oxide layer 6 on the substrate 1 (S 402 ); forming a first metal oxide layer 70 on the chemical oxide layer 6 (S 404 ); forming a first metal layer 71 on the first metal oxide layer 70 (S 406 ); forming a second metal layer 72 on the first metal layer 71 (S 408 ); and forming a second metal oxide layer 73 on the second metal layer 72 (S 410 ). Hence, the first metal oxide layer 70 , the first metal layer 71 , the second metal layer 72 and the second metal oxide layer 73 are stacked sequentially to form the dielectric layer unit 7 . Next, the method comprises forming a conducting layer 3 on the second metal oxide layer 73 (S 412 ). Moreover, both the dielectric layer unit 7 and the conducting layer 3 are formed by a LTCVD (Low Temperature Chemical Vapor Deposition) that is an ALD (Atomic Layer Deposition) device.
[0041] Furthermore, after the step S 412 , the method further comprises: performing annealing to form a stacked gate (S 414 ); performing S/D (Source/Drain) annealing upon the stacked gate (S 416 ); and performing forming gas annealing (S 418 ). In addition, during the step S 416 and the step S 418 , oxygen is doped into Ti to from TiO 2 .
[0042] To sum up, the present invention forms Ti on the HfO 2 absorb oxygen atoms from the dielectric layer so as to reduce its thickness, and even make it disappear. However, the TiO 2 that is grown on the layer of Ti can advance the growing of the following HfO 2 . Simultaneously, the dielectric constant of TiO 2 is about 50, so it enhances the dielectric constant for the dielectric layer of the gate substantially. In conclusion, Ti is used to absorb the oxygen atoms so as to reduce its thickness and increase dielectric constant, and to reduce EOT further. Moreover, TiO 2 is formed and the dielectric constant is increased as well after a heating process. Accordingly, leakage can be avoided in the TiO 2 . Consequently, the present invention enhances the application for the high-k gate dielectric with a high electric constant, and continuously reduces the EOT.
[0043] Furthermore, compared with the example presented by Hyoung Kim et al., the present invention effectively reduces the damage caused by the HfO 2 by using a CVD method to perform a continuous coating process. In addition, the present invention's Ti layer is formed on the HfO 2 layer, and the Ti layer is close to an oxide layer to increase the efficiency of the Ti to absorb the oxygen atoms. Moreover, the Ti layer is doped into the dielectric layer. Hence, after the Ti layer absorbs the oxygen atom, it can be changed to TiO 2 so as to increase the dielectric constant k and reduce EOT.
[0044] Although the present invention has been described with reference to the preferred best molds thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims. | A semiconductor structure and method for manufacturing the same is disclosed. The present invention relates to a semiconductor having a dielectric layer applied on a gate of a transistor, and a high dielectric-coefficient, and a manufacturing method of the semiconductor. Ti is formed on HfO 2 to absorb oxygen from the dielectric layer to reduce its thickness, and even make it disappear. However, the TiO 2 grown on the layer of Ti advances the growing of HfO 2 . Simultaneously, the dielectric constant of TiO 2 is about 50. The TiO 2 substantially enhances the dielectric constant for the dielectric layer. Ti absorbs the oxygen to reduce its thickness and increase the dielectric constant to reduce EOT. Moreover, TiO 2 is formed and the dielectric constant is increased after heating. Accordingly, leakage is avoided in the TiO 2 . The present invention enhances the applications for high-k gate dielectrics with high electric constants, and continuously reduces the EOT. | Briefly summarize the main idea's components and working principles as described in the context. | [
"BACKGROUND OF THE INVENTION [0001] 1.",
"Field of the Invention [0002] The present invention relates to a semiconductor structure and a method for manufacturing the same, and particularly relates to a semiconductor having a dielectric layer applied on a gate of a transistor, and a high dielectric-coefficient, and a manufacturing method for the semiconductor.",
"[0003] 2.",
"Description of the Related Art [0004] In the semiconductor process, the function of dielectric layer is to act as an insulating material, such as SiO2 or SiN, for insulating from electrical signals between a conducting layer and a conducting wire.",
"Moreover, it is know that the dielectric layers such as HfO and Si x N x are going to be applied to transistor gates in the future.",
"Hence an atomic layer deposition method will be the main technology used to form a dielectric thin film.",
"However, although forming Si x N x increases the stability of the dielectric thin film structure, the dielectric constant k is decreased.",
"Moreover, in the atomic layer deposition technology, high quality HfSiO needs to be grown in an environment that is full of oxygen.",
"In other words, HfSiO needs to be grown on an oxide layer.",
"Furthermore, when the thickness of the oxide layer is about 5˜10 Å, it becomes an impediment to achieving high dielectric constants and low EOTs (Equivalent Oxide Thickness).",
"Hence, it is vital for micro transistor technology that the thickness of the dielectric layer is reduced in the future.",
"[0005] In The Journal of Applied Physics Hyoung Kim et al published “Engineering chemically abrupt high-k metal oxide/Silicon interfaces using an oxygen-gettering metal overlayer”",
"(Vol.",
"96 No. 6, page 3467-3472, 2004).",
"The article discussed a Ti layer with HfO2 grown on it to absorb oxygen atoms for removing a dielectric layer.",
"However, when the Ti:O is removed, the HfO 2 will be damaged in the removal process.",
"Moreover, the Ti layer is formed on the HfO2 by PVD (Physical Vapor Deposition).",
"Hence the HfO2 film will be harmed by the high power particles produced from the PVD.",
"Furthermore, because there is a predetermined distance between the Ti layer and the HfO 2 layer, the absorbing efficiency of the Ti layer is decreased when the Ti layer absorbs the oxygen atoms.",
"SUMMARY OF THE INVENTION [0006] The present invention provides a semiconductor structure and method for manufacturing the same.",
"The semiconductor structure reduces the thickness of a dielectric layer thereof.",
"Moreover, the present invention is adapted to a future transistor manufacturing process, and can certainly integrate PMOS together with NMOS.",
"[0007] In order to achieve the above objects, a semiconductor structure and a method for manufacturing the same is disclosed.",
"Particularly, the present invention relates to a semiconductor having a dielectric layer applied on a gate of a transistor, and a high dielectric-coefficient, and a manufacturing method for the semiconductor.",
"Ti is formed on the HfO 2 for absorbing oxygen atoms from the dielectric layer so as to reduce its thickness, and even to a point where it disappears completely.",
"However, any TiO 2 grown on the layer of the Ti can advance the growing of the following HfO 2 .",
"Simultaneously, the dielectric constant of TiO 2 is about 50, which enhances the dielectric constant for the dielectric layer of the gate substantially.",
"In conclusion, Ti is used to absorb the oxygen atoms so as to reduce their thickness and increase the dielectric constant, and to further reduce EOT.",
"Moreover, TiO 2 is formed and the dielectric constant is increased as well after a heating process.",
"Accordingly, leakage can be avoided in the TiO 2 .",
"Consequently, the present invention enhances the application of high-k gate dielectric with high electric constant, and continuously reduces the EOT.",
"[0008] A first aspect of the present invention is a semiconductor structure.",
"The semiconductor structure comprises a substrate, a dielectric layer unit and a conducting layer.",
"The dielectric layer unit is formed on the substrate, and the dielectric layer includes at least a metal oxide layer and a metal layer stacked on each other.",
"The conducting layer is formed on the dielectric layer unit.",
"[0009] A second aspect of the present invention is a method for manufacturing a semiconductor structure.",
"The method comprises: providing a substrate;",
"forming a dielectric layer unit on the substrate, wherein the dielectric layer includes at least a metal oxide layer and a metal layer stacked on each other;",
"and forming a conducting layer on the dielectric layer unit.",
"[0010] Moreover, in the first and second aspects, the metal oxide layer comprises at least a first metal oxide layer and a second metal oxide layer.",
"The metal layer comprises at least a first metal layer.",
"The first metal layer, the first metal oxide layer and the second metal oxide layer are stacked sequentially to form the dielectric layer unit.",
"[0011] Furthermore, in the first and second aspects, the metal oxide layer comprises at least a first metal oxide layer, a second metal oxide layer and a third metal oxide layer.",
"The metal layer comprises at least a second metal layer.",
"The first metal oxide layer, the second metal layer, the second metal oxide layer and the third metal oxide layer are stacked sequentially to form the dielectric layer unit.",
"[0012] A third aspect of the present invention is a method for manufacturing a semiconductor structure.",
"The method comprises: providing a substrate;",
"forming a chemical oxide layer on the substrate;",
"forming a first metal oxide layer on the chemical oxide layer;",
"forming a first metal layer on the first metal oxide layer;",
"forming a second metal layer on the first metal layer;",
"forming a second metal oxide layer on the second metal layer;",
"and forming a conducting layer on the second metal oxide layer.",
"[0013] A fourth aspect of the present invention is a semiconductor structure.",
"The semiconductor structure comprises a substrate, a chemical oxide layer formed on the substrate, a first metal oxide layer formed on the chemical oxide layer, a first metal layer formed on the first metal oxide layer, a second metal layer formed on the first metal layer, a second metal oxide layer formed on the second metal layer, and a conducting layer formed on the second metal oxide layer.",
"[0014] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.",
"Other advantages and features of the invention will be apparent from the following description, drawings and claims.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0015] The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which: [0016] FIG. 1 is a schematic, cross-sectional view of a semiconductor structure according to the first embodiment of the present invention;",
"[0017] FIG. 2 is a schematic, cross-sectional view of a semiconductor structure according to the second embodiment of the present invention;",
"[0018] FIG. 3 is a schematic, cross-sectional view of a semiconductor structure according to the third embodiment of the present invention;",
"[0019] FIG. 4 is a schematic, cross-sectional view of a semiconductor structure according to the fourth embodiment of the present invention;",
"[0020] FIG. 5 is a flowchart of a method for manufacturing a semiconductor structure according to the first embodiment of the present invention;",
"[0021] FIG. 6 is a flowchart of a method for manufacturing a semiconductor structure according to the second embodiment of the present invention;",
"[0022] FIG. 7 is a flowchart of a method for manufacturing a semiconductor structure according to the third embodiment of the present invention;",
"and [0023] FIG. 8 is a flowchart of a method for manufacturing a semiconductor structure according to the fourth embodiment of the present invention.",
"DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0024] FIG. 1 shows a schematic, cross-sectional view of a semiconductor structure according to the first embodiment of the present invention.",
"The present invention provides a semiconductor structure, comprising a substrate 1 , a dielectric layer unit 2 and a conducting layer 3 .",
"[0025] The substrate 1 can be a Si substrate that has a SiO 2 formed thereon.",
"The dielectric layer unit 2 is formed on the substrate 1 , and the dielectric layer 2 includes at least a metal oxide layer 20 and a metal layer 21 stacked upon each other.",
"The conducting layer 3 is formed on the dielectric layer unit 2 , and the conducting layer 3 can be TiN.",
"[0026] Moreover, the metal oxide layer 20 can be HfO 2 , HfSiO, HfSiON or TiO 2 .",
"The thickness of both the HfO 2 and the HfSiO can be between 0.1˜3 nm or 0.1˜5 nm, the thickness of the HfSiON can be between 0.1˜3 nm, and the thickness of the TiO 2 can be between 0.1˜2 nm.",
"The metal layer 21 can be Ti, and the thickness of the Ti can be between 0.1˜2 nm.",
"However, both the thickness and material of the metal oxide layer or the metal layer should not be used to limit the present invention.",
"[0027] FIG. 2 shows a schematic, cross-sectional view of a semiconductor structure according to the second embodiment of the present invention.",
"The present invention provides a semiconductor structure, comprising a substrate 1 , a dielectric layer unit 4 , and a conducting layer 3 .",
"[0028] The second embodiment differs from the first embodiment in that the dielectric layer unit 4 has a first metal layer 40 , a first metal oxide layer 41 , and a second metal oxide layer 42 stacked sequentially.",
"The first metal layer 40 can be Ti, and the thickness of the Ti is between 0.1˜2 nm.",
"Both the first metal oxide layer 41 and the second metal oxide layer 42 can be HfO 2 , HfSiO, HfSiON, or TiO 2 .",
"The thickness of the HfO 2 , HfSiO, HfSiON, or TiO 2 are all between 0.1˜3 nm or 0.1˜5 nm.",
"Moreover, the total thickness of both the first metal layer and the first metal oxide layer can be between 0.1˜2 nm.",
"However, both the thickness and material of the metal oxide layer or the metal layer should not be used to limit the present invention.",
"[0029] FIG. 3 shows a schematic, cross-sectional view of a semiconductor structure according to the third embodiment of the present invention.",
"The present invention provides a semiconductor structure, comprising a substrate 1 , a dielectric layer unit 5 , and a conducting layer 3 .",
"[0030] The third embodiment differs from the first and second embodiments in that the dielectric layer unit 5 has a first metal oxide layer 50 , a second metal layer 51 , a second metal oxide layer 52 , and a third metal oxide layer 53 stacked sequentially.",
"The second metal layer can be Ti, and the thickness of the second metal layer can be between 0.1˜2 nm.",
"The first metal oxide layer 50 can be HfO 2 , HfSiO or HfSiON, and the thickness of the first metal oxide layer 50 can be between 0.1˜3 nm or 0.1˜5 nm.",
"The second metal oxide layer 52 can be TiO 2 .",
"The third metal oxide layer 53 can be HfO 2 , HfSiO or HfSiON, and the thickness of the first metal oxide layer 53 can be between 0.1˜3 nm or 0.1˜5 nm.",
"However, both the thickness and material of the metal oxide layer or the metal layer should not be used to limit the present invention.",
"[0031] FIG. 4 shows a schematic, cross-sectional view of a semiconductor structure according to the fourth embodiment of the present invention.",
"The present invention provides a semiconductor structure comprising a substrate 1 , a chemical oxide layer 6 , a first metal oxide layer 70 , a first metal layer 71 , a second metal layer 72 , a second metal oxide layer 73 , and a conducting layer 3 .",
"[0032] The chemical oxide layer 6 is formed on the substrate 1 .",
"The first metal oxide layer 70 is formed on the chemical oxide layer 6 .",
"The first metal layer 71 is formed on the first metal oxide layer 70 .",
"The second metal layer 72 is formed on the first metal layer 71 .",
"The second metal oxide layer 73 is formed on the second metal layer 72 .",
"The conducting layer 3 is formed on the second metal oxide layer 73 .",
"Hence the first metal oxide layer 70 , the first metal layer 71 , the second metal layer 72 , and the second metal oxide layer 73 can be stacked sequentially to form a dielectric layer unit 7 .",
"[0033] Moreover, both the first metal oxide layer 70 and the second metal oxide layer 73 can be HfO 2 , HfSiO, HfSiON, or TiO 2 , and their thickness can be between 0.1˜3 nm or 0.1˜5 nm.",
"Both the first metal layer 71 and the second metal layer 72 can be Ti, and its thickness can be between 0.1˜2 nm.",
"Furthermore, as in the first embodiment, the substrate 1 can be a Si substrate that has a SiO 2 formed thereon.",
"[0034] FIG. 5 shows a flowchart of a method for manufacturing a semiconductor structure according to the first embodiment of the present invention.",
"The present invention provides a method for manufacturing a semiconductor structure, comprising: providing a substrate 1 (S 100 );",
"forming a metal oxide layer 20 on the substrate 1 (S 102 );",
"and forming a metal layer 21 on the metal oxide layer 20 (S 104 ).",
"Hence the metal oxide layer 20 and the metal layer 21 are stacked upon each other to form a dielectric layer unit 2 .",
"Next, the method comprises forming a conducting layer 3 on the metal layer 21 (S 106 ).",
"Moreover, both the dielectric layer unit 2 and the conducting layer 3 are formed by a LTCVD (Low Temperature Chemical Vapor Deposition) that is an ALD (Atomic Layer Deposition) device.",
"[0035] Furthermore, after the step S 106 , the method further comprises: performing annealing to form a stacked gate (S 108 );",
"performing S/D (Source/Drain) annealing upon the stacked gate (S 110 );",
"and performing forming gas annealing (S 112 ).",
"In addition, during the step S 110 and the step S 112 , oxygen is doped into Ti to from TiO 2 .",
"[0036] FIG. 6 shows a flowchart of a method for manufacturing a semiconductor structure according to the second embodiment of the present invention.",
"The present invention provides a method for manufacturing a semiconductor structure, comprising: providing a substrate 1 (S 200 );",
"forming a first metal layer 40 on the substrate 1 (S 202 );",
"forming a first metal oxide layer 41 on the first metal layer 40 (S 204 );",
"and forming a second metal oxide layer 42 on the first metal oxide layer 41 (S 206 ).",
"Hence the first metal layer 40 , the first metal oxide layer 41 and the second metal oxide layer 42 are stacked sequentially to form the dielectric layer unit 4 .",
"Next, the method comprises forming a conducting layer 3 on the second metal oxide layer 42 (S 208 ).",
"Moreover, both the dielectric layer unit 4 and the conducting layer 3 are formed by a LTCVD (Low Temperature Chemical Vapor Deposition) that is an ALD (Atomic Layer Deposition) device.",
"[0037] Furthermore, after the step S 208 , the method further comprises: performing annealing to form a stacked gate (S 210 );",
"performing S/D (Source/Drain) annealing upon the stacked gate (S 212 );",
"and performing forming gas annealing (S 214 ).",
"In addition, during the step S 212 and the step S 214 , oxygen is doped into Ti to from TiO 2 .",
"[0038] FIG. 7 shows a flowchart of a method for manufacturing a semiconductor structure according to the third embodiment of the present invention.",
"The present invention provides a method for manufacturing a semiconductor structure, comprising: providing a substrate 1 (S 300 );",
"forming a first metal oxide layer 50 on the substrate 1 (S 302 );",
"forming a second metal layer 51 on the first metal oxide layer 50 (S 304 );",
"forming a second metal oxide layer 52 on the second metal layer 51 (S 306 );",
"and forming a third metal oxide layer 53 on the second metal oxide layer 52 (S 308 ).",
"Hence the first metal oxide layer 50 , the second metal layer 51 , the second metal oxide layer 52 and the third metal oxide layer 53 are stacked sequentially to form the dielectric layer unit 5 .",
"Next, the method comprises forming a conducting layer 3 on the third metal oxide layer 53 (S 310 ).",
"Moreover, both the dielectric layer unit 5 and the conducting layer 3 are formed by a LTCVD (Low Temperature Chemical Vapor Deposition) that is an ALD (Atomic Layer Deposition) device.",
"[0039] Furthermore, after the step S 310 , the method further comprises: performing annealing to form a stacked gate (S 312 );",
"performing S/D (Source/Drain) annealing upon the stacked gate (S 314 );",
"and performing forming gas annealing (S 316 ).",
"In addition, during the step S 314 and the step S 316 , oxygen is doped into Ti to from TiO 2 .",
"[0040] FIG. 8 shows a flowchart of a method for manufacturing a semiconductor structure according to the fourth embodiment of the present invention.",
"The present invention provides a method for manufacturing a semiconductor structure, comprising: providing a substrate 1 (S 400 );",
"forming a chemical oxide layer 6 on the substrate 1 (S 402 );",
"forming a first metal oxide layer 70 on the chemical oxide layer 6 (S 404 );",
"forming a first metal layer 71 on the first metal oxide layer 70 (S 406 );",
"forming a second metal layer 72 on the first metal layer 71 (S 408 );",
"and forming a second metal oxide layer 73 on the second metal layer 72 (S 410 ).",
"Hence, the first metal oxide layer 70 , the first metal layer 71 , the second metal layer 72 and the second metal oxide layer 73 are stacked sequentially to form the dielectric layer unit 7 .",
"Next, the method comprises forming a conducting layer 3 on the second metal oxide layer 73 (S 412 ).",
"Moreover, both the dielectric layer unit 7 and the conducting layer 3 are formed by a LTCVD (Low Temperature Chemical Vapor Deposition) that is an ALD (Atomic Layer Deposition) device.",
"[0041] Furthermore, after the step S 412 , the method further comprises: performing annealing to form a stacked gate (S 414 );",
"performing S/D (Source/Drain) annealing upon the stacked gate (S 416 );",
"and performing forming gas annealing (S 418 ).",
"In addition, during the step S 416 and the step S 418 , oxygen is doped into Ti to from TiO 2 .",
"[0042] To sum up, the present invention forms Ti on the HfO 2 absorb oxygen atoms from the dielectric layer so as to reduce its thickness, and even make it disappear.",
"However, the TiO 2 that is grown on the layer of Ti can advance the growing of the following HfO 2 .",
"Simultaneously, the dielectric constant of TiO 2 is about 50, so it enhances the dielectric constant for the dielectric layer of the gate substantially.",
"In conclusion, Ti is used to absorb the oxygen atoms so as to reduce its thickness and increase dielectric constant, and to reduce EOT further.",
"Moreover, TiO 2 is formed and the dielectric constant is increased as well after a heating process.",
"Accordingly, leakage can be avoided in the TiO 2 .",
"Consequently, the present invention enhances the application for the high-k gate dielectric with a high electric constant, and continuously reduces the EOT.",
"[0043] Furthermore, compared with the example presented by Hyoung Kim et al.",
", the present invention effectively reduces the damage caused by the HfO 2 by using a CVD method to perform a continuous coating process.",
"In addition, the present invention's Ti layer is formed on the HfO 2 layer, and the Ti layer is close to an oxide layer to increase the efficiency of the Ti to absorb the oxygen atoms.",
"Moreover, the Ti layer is doped into the dielectric layer.",
"Hence, after the Ti layer absorbs the oxygen atom, it can be changed to TiO 2 so as to increase the dielectric constant k and reduce EOT.",
"[0044] Although the present invention has been described with reference to the preferred best molds thereof, it will be understood that the invention is not limited to the details thereof.",
"Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art.",
"Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims."
] |
The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment of any royalties thereon or therefor.
This application is a continuation of application Ser. No. 07/171,323, filed Mar. 21, 1988, now abandoned.
TECHNICAL FIELD
This invention relates generally to mixers and more particularly to millimeter-wave monolithic mixers.
BACKGROUND OF THE INVENTION
A mixer is a device which converts an incoming from one frequency to another by combining it with a local oscillator signal in a non-linear device. In general, mixing produces a large number of sum and difference frequencies. Usually, the difference frequency between the signal (RF frequency) and local oscillator (LO frequency) is of interest. Mixers are often used in radar systems to convert an incoming RF before further processing.
Monolithic technology has been widely used at lower frequencies (less than 30 GHz) and has proven to be attractive for addressing the problems of cost, size and weight. Those concerned with the development of radars into the millimeter-wave region must often deal with parts which require precise tolerances and are difficult to fabricate. There is a continuing need for low cost radar components with designs amenable to mass production.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a mixing device suitable for use in high frequency communication and radar systems.
A further object of the present invention is to provide a low cost mass-producible, dielectric compatible mixing device suitable for application in modern millimeter-wave radar systems.
Still another object of the present invention is to provide a signal mixer fabricated as a monolithic integrated circuit structure.
Briefly, these and other objects are accomplished with a gallium arsenide (or other semiconductor) image guide structure with two in-situ Schottky barrier diodes. The two Schottky diodes provide an IF signal with a frequency which is the difference between the incident RF signal and the local oscillator LO signal. (Of course, other frequencies are also produced). The outputs from the Schottky diodes are coupled to a microstrip low pass filter to isolate the desired IF frequency.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantages of the present will become apparent to those familiar with the art upon examination of the following detailed description and accompanying drawings in which:
FIG. 1 is a partially perspective, partially schematic view of the inventive device; and
FIG. 2 is a cross sectional view of a portion of FIG. 1 showing the details of the Schottky barrier diode construction.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the inventive device is shown generally by reference numeral 11. A metallic end plate is designated by reference numeral 13. A Y-shaped gallium arsenide image guide 15 is deposited upon metallic end plate 13. The input RF and local oscillator LO signals are coupled to end 17 of image guide 15.
The image guide 15 is preferentially made from semi-insulating gallium arsenide. Semi-insulating gallium arsenide is doped with chromium which tends to pin the Fermi level near the center of the energy band gap, thus producing a material with a high resistivity and high dielectric constant.
Application of theoretical considerations indicates that the height, h, of image guide 15 should be roughly one-half to one wavelength (in the RF or LO signal) in the semiconductor medium. Obviously, the relative heights of image guide 15 and metallic end plate 13 are not drawn to scale in the interests of clarity.
Both the RF and LO signals propagate together through image guide 15 until branch point 19 is reached. At point 19, half of the combined incident power goes into leg 21, while the other half of the combined incident power proceeds into leg 23 of image guide 15.
Both legs 21 and 23 contain respective Schottky diodes 25 and 27. It should be noted that Schottky diodes 27 and 25 are oriented in opposite directions. The opposite orientation of Schottky diodes 25 and 27 permits maximum utilization of the power from the combined RF and LO signals.
The details of the construction and orientation of Schottky diode 25 in leg 21 will now be discussed. The discussion is also appropriate to the construction of leg 23 and its associated Schottky diode 27, except for diode orientation.
As the combined RF and LO signals proceed from branch point 19 through leg 21 they encounter gold metallization 31. Gold metallization 31 is deposited as a thin film upon the top of leg 21. Projection 29 of gold metallization 31 provides a resonance effect which prevents backward reflection of the combined incident RF and LO signals.
The details of the construction Schottky diode 25 can best be understood with reference to FIG. 2. Schottky diode 25 is grown in-situ by well-known vapor phase epitaxy or molecular beam epitaxy techniques. A layer of n + gallium arsenide material 33 is deposited in a cavity in the semi-insulating gallium arsenide material forming leg 21. A layer of n gallium arsenide material 35 is deposited upon layer 33. Layer 35 does not completely cover layer 33. A Schottky barrier is formed upon the top of layer 35 by deposition of a titanium gold composition metal 37. Layer 37 does not completely cover layer 35. A gold beam lead 41 (shown in both FIGS. 1 and 2) forms electrical contact with the titanium gold composition 37. Contact between the beam lead 41 and the n layer 35 and n + layer 33 is prevented by dielectric 39 which is preferably silicon nitride. Layer 43 is ohmic metal, preferably gold germanium nickel alloy and it contacts the n + layer 33. Layer 43 may be covered by a gold beam lead on top, if desired. Beam lead 43 is also illustrated in FIG. 1. As seen in FIG. 1, beam lead 41 is connected to the cathode of diode 25, while 43 is connected to the anode of diode 75.
Beam lead 43 contacts gold metallization 45. The distance between points 47 and 49 of gold metallization 45 is chosen to be approximately 1/2 wave length of the local oscillator frequency in the semiconductor material (gallium arsenide in the embodiment illustrated herein). The dimensioning between points 47 and 49 is chosen to provide cancellation of the RF and LO frequencies, thus permitting only the sum and difference frequencies and their harmonics to propagate. Terminal 51 is connected to terminal 53 of low pass filter 55 by connector 57. Connector 57 may be made from gold wire. To prevent radiation, in a preferred embodiment, connector 57 is a small coaxial cable whose outer sheath is tied to ground plane 13.
Low pass filter 55 is designed according to techniques well-known to those skilled in the art. In a preferred embodiment low pass filter 55 is made from DUROID. DUROID is the name of a trademarked material which contains a dielectric material 71 between two copper sheets 73 and 75. The DUROID low pass filter may be attached to metallic end plate 13 by conductive epoxy. The configuration of low pass filter 55 is determined by techniques well-known to those skilled in the art. The configuration illustrated in FIG. 1 shows broad capacitive elements 61 and 65 together with inductive portions 59 and 63. Low pass filter 55 permits only the desired difference frequency (IF frequency) to propagate while attenuating other undesired frequencies.
Arm 23 works like arm 21. Metallizations 81 and 83 are configured similar to metallizations 31 and 45. Schottky diode 27 is fabricated in the manner analogous to that described for Schottky diode 25--except that cathode and anode are reversed. Connector 87 connects terminals 85 and 53 in a manner analogous to that in which connector 57 connects terminals 51 and 53.
This novel monolithic mixer device can be fabricated in large volumes using a cutting device to punch out gallium arsenide image guide 15 and then processing the in-situ Schottky diodes 25 and 27.
The illustrative embodiment herein is merely one of those possible variations which will occur to those skilled in the art the inventive principles contained herein. Accordingly, numerous variations of invention are possible while staying within the spirit and scope of the invention as defined in the following claims and their legal equivalents. | A monolithic millimeter wave balanced mixer in which two Schottky barrier odes receive combined power from. Two Schottky barrier diodes receive combined power from an RF source and local oscillator in a gallium arsenide image guide. The diodes produce an intermediate frequency which is directed to a microstrip low pass filter. | Briefly describe the main invention outlined in the provided context. | [
"The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment of any royalties thereon or therefor.",
"This application is a continuation of application Ser.",
"No. 07/171,323, filed Mar. 21, 1988, now abandoned.",
"TECHNICAL FIELD This invention relates generally to mixers and more particularly to millimeter-wave monolithic mixers.",
"BACKGROUND OF THE INVENTION A mixer is a device which converts an incoming from one frequency to another by combining it with a local oscillator signal in a non-linear device.",
"In general, mixing produces a large number of sum and difference frequencies.",
"Usually, the difference frequency between the signal (RF frequency) and local oscillator (LO frequency) is of interest.",
"Mixers are often used in radar systems to convert an incoming RF before further processing.",
"Monolithic technology has been widely used at lower frequencies (less than 30 GHz) and has proven to be attractive for addressing the problems of cost, size and weight.",
"Those concerned with the development of radars into the millimeter-wave region must often deal with parts which require precise tolerances and are difficult to fabricate.",
"There is a continuing need for low cost radar components with designs amenable to mass production.",
"SUMMARY OF THE INVENTION Accordingly, it is an object of the invention to provide a mixing device suitable for use in high frequency communication and radar systems.",
"A further object of the present invention is to provide a low cost mass-producible, dielectric compatible mixing device suitable for application in modern millimeter-wave radar systems.",
"Still another object of the present invention is to provide a signal mixer fabricated as a monolithic integrated circuit structure.",
"Briefly, these and other objects are accomplished with a gallium arsenide (or other semiconductor) image guide structure with two in-situ Schottky barrier diodes.",
"The two Schottky diodes provide an IF signal with a frequency which is the difference between the incident RF signal and the local oscillator LO signal.",
"(Of course, other frequencies are also produced).",
"The outputs from the Schottky diodes are coupled to a microstrip low pass filter to isolate the desired IF frequency.",
"BRIEF DESCRIPTION OF THE DRAWINGS Further objects and advantages of the present will become apparent to those familiar with the art upon examination of the following detailed description and accompanying drawings in which: FIG. 1 is a partially perspective, partially schematic view of the inventive device;",
"and FIG. 2 is a cross sectional view of a portion of FIG. 1 showing the details of the Schottky barrier diode construction.",
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the inventive device is shown generally by reference numeral 11.",
"A metallic end plate is designated by reference numeral 13.",
"A Y-shaped gallium arsenide image guide 15 is deposited upon metallic end plate 13.",
"The input RF and local oscillator LO signals are coupled to end 17 of image guide 15.",
"The image guide 15 is preferentially made from semi-insulating gallium arsenide.",
"Semi-insulating gallium arsenide is doped with chromium which tends to pin the Fermi level near the center of the energy band gap, thus producing a material with a high resistivity and high dielectric constant.",
"Application of theoretical considerations indicates that the height, h, of image guide 15 should be roughly one-half to one wavelength (in the RF or LO signal) in the semiconductor medium.",
"Obviously, the relative heights of image guide 15 and metallic end plate 13 are not drawn to scale in the interests of clarity.",
"Both the RF and LO signals propagate together through image guide 15 until branch point 19 is reached.",
"At point 19, half of the combined incident power goes into leg 21, while the other half of the combined incident power proceeds into leg 23 of image guide 15.",
"Both legs 21 and 23 contain respective Schottky diodes 25 and 27.",
"It should be noted that Schottky diodes 27 and 25 are oriented in opposite directions.",
"The opposite orientation of Schottky diodes 25 and 27 permits maximum utilization of the power from the combined RF and LO signals.",
"The details of the construction and orientation of Schottky diode 25 in leg 21 will now be discussed.",
"The discussion is also appropriate to the construction of leg 23 and its associated Schottky diode 27, except for diode orientation.",
"As the combined RF and LO signals proceed from branch point 19 through leg 21 they encounter gold metallization 31.",
"Gold metallization 31 is deposited as a thin film upon the top of leg 21.",
"Projection 29 of gold metallization 31 provides a resonance effect which prevents backward reflection of the combined incident RF and LO signals.",
"The details of the construction Schottky diode 25 can best be understood with reference to FIG. 2. Schottky diode 25 is grown in-situ by well-known vapor phase epitaxy or molecular beam epitaxy techniques.",
"A layer of n + gallium arsenide material 33 is deposited in a cavity in the semi-insulating gallium arsenide material forming leg 21.",
"A layer of n gallium arsenide material 35 is deposited upon layer 33.",
"Layer 35 does not completely cover layer 33.",
"A Schottky barrier is formed upon the top of layer 35 by deposition of a titanium gold composition metal 37.",
"Layer 37 does not completely cover layer 35.",
"A gold beam lead 41 (shown in both FIGS. 1 and 2) forms electrical contact with the titanium gold composition 37.",
"Contact between the beam lead 41 and the n layer 35 and n + layer 33 is prevented by dielectric 39 which is preferably silicon nitride.",
"Layer 43 is ohmic metal, preferably gold germanium nickel alloy and it contacts the n + layer 33.",
"Layer 43 may be covered by a gold beam lead on top, if desired.",
"Beam lead 43 is also illustrated in FIG. 1. As seen in FIG. 1, beam lead 41 is connected to the cathode of diode 25, while 43 is connected to the anode of diode 75.",
"Beam lead 43 contacts gold metallization 45.",
"The distance between points 47 and 49 of gold metallization 45 is chosen to be approximately 1/2 wave length of the local oscillator frequency in the semiconductor material (gallium arsenide in the embodiment illustrated herein).",
"The dimensioning between points 47 and 49 is chosen to provide cancellation of the RF and LO frequencies, thus permitting only the sum and difference frequencies and their harmonics to propagate.",
"Terminal 51 is connected to terminal 53 of low pass filter 55 by connector 57.",
"Connector 57 may be made from gold wire.",
"To prevent radiation, in a preferred embodiment, connector 57 is a small coaxial cable whose outer sheath is tied to ground plane 13.",
"Low pass filter 55 is designed according to techniques well-known to those skilled in the art.",
"In a preferred embodiment low pass filter 55 is made from DUROID.",
"DUROID is the name of a trademarked material which contains a dielectric material 71 between two copper sheets 73 and 75.",
"The DUROID low pass filter may be attached to metallic end plate 13 by conductive epoxy.",
"The configuration of low pass filter 55 is determined by techniques well-known to those skilled in the art.",
"The configuration illustrated in FIG. 1 shows broad capacitive elements 61 and 65 together with inductive portions 59 and 63.",
"Low pass filter 55 permits only the desired difference frequency (IF frequency) to propagate while attenuating other undesired frequencies.",
"Arm 23 works like arm 21.",
"Metallizations 81 and 83 are configured similar to metallizations 31 and 45.",
"Schottky diode 27 is fabricated in the manner analogous to that described for Schottky diode 25--except that cathode and anode are reversed.",
"Connector 87 connects terminals 85 and 53 in a manner analogous to that in which connector 57 connects terminals 51 and 53.",
"This novel monolithic mixer device can be fabricated in large volumes using a cutting device to punch out gallium arsenide image guide 15 and then processing the in-situ Schottky diodes 25 and 27.",
"The illustrative embodiment herein is merely one of those possible variations which will occur to those skilled in the art the inventive principles contained herein.",
"Accordingly, numerous variations of invention are possible while staying within the spirit and scope of the invention as defined in the following claims and their legal equivalents."
] |
This application is a Division of application Ser. No. 14/170,786 filed Feb. 3, 2014 and issued as U.S. Pat. No. 9,071,723 on Jun. 30, 2012, which is a Division of application Ser. No. 13/347,633 filed Jan. 10, 2012 and issued as U.S. Pat. No. 8,810,659 on Aug. 19, 2014, which is a Division of application Ser. No. 12/471,127 filed May 22, 2009 and issued as U.S. Pat. No. 8,159,610 on Apr. 17, 2012, which is a Division of Ser. No. 10/894,746 filed Jul. 19, 2004 and issued as U.S. Pat. No. 7,710,499 on May 4, 2010 which is a Division of application Ser. No. 09/545,529 filed Apr. 7, 2000 and issued as U.S. Pat. No. 6,836,295 on Dec. 28, 2004 all of which are incorporated herein by reference as fully as if they had been set out in detail and to which priority is claimed. Application Ser. No. 09/545,529 is in turn a Continuation-in-part of application Ser. No. 09/119,524 filed Jul. 21, 1998 and issued as U.S. Pat. No. 6,351,281 on Feb. 26, 2002 which is a Division of application Ser. No. 08/620,126 filed Mar. 21, 1996 which issued as U.S. Pat. No. 6,330,033 on Dec. 11, 2001 which claims benefit of Provisional Application 60/008,309 filed Dec. 7, 1995. No priority to application Ser. No. 09/119,524, U.S. Pat. No. 6,351,281, application Ser. No. 08/620,126, U.S. Pat. No. 6,330,033 or Application 60/008,309 is claimed, but which are incorporated herein by reference, in respect to their prior art teachings.
The examiner's attention is called to incorrectly published U.S. Pat. No. 5,847,769 which is related to the present application by virtue of common application Ser. No. 08/620,126. The '769 patent was withdrawn from issue. Despite the fact of the patent being withdrawn from issue it was nevertheless published by the Patent Office. Applicant brings this withdrawn patent to the attention of the examiner out of applicant's duty of candor.
BACKGROUND OF THE INVENTION
The invention relates to measuring, maintaining and correcting synchronization between two signals which suffer varying relative delays during transmission and/or storage, and in particular to measuring the relative delay between multiple audio signals and an associated video signal of a television type program which is compressed via MPEG or other compression method for transmission and/or storage.
1. Field of the Invention
The present invention relates to the field of transmitting and storing multiple electronic signals where synchronization of the signals is of concern. When such transmitting and storing are of a nature which makes the corresponding receiving and recovering of said signals subject to timing errors resulting from differing amounts of processing delays the present invention is useful in measuring the relative timing errors or delays between signals with such delay measurement being used as a meter of quality of the transmitting and storing and for maintaining or correction of relative delays between such signals.
2. Description of Related Prior Art
It is known in the television signal transmission field to measure and correct audio to video timing errors by measuring the delay which a video signal experiences and using that measurement to delay a companion audio signal by a corresponding amount.
U.S. Pat. No. 4,313,135 by the present inventor shows to compare relatively undelayed and delayed versions of the same video signal to provide a delay signal responsive to the delay thereof and to couple that delay signal to a variable audio delay to cause the audio delay to delay the companion audio signal by a corresponding amount.
U.S. Pat. Nos. 4,665,431 and 5,675,388 by the present inventor show transmitting an audio signal as part of a video signal so that both the audio and video signals experience the same transmission delays thus maintaining the relative synchronization therebetween.
U.S. Reissue Pat. No. RE 33,535 corresponding to U.S. Pat. No. 4,703,355 shows in the preferred embodiment to encode in the vertical interval of a video signal, a timing signal derived from an audio signal and transmitting the combined video signal and the audio signal. At the receiving location the timing signal is recovered from the video signal and a new timing signal is generated from the received audio signal. The two timing signals are compared at the receiving location to determine the relative delay between the timing signal recovered from the video and the newly generated timing signal, thus determining the relative delay between the video and audio signals at the receive location. It is also suggested to put a timing signal in the audio signal.
U.S. Pat. No. 5,202,761 by the present inventor shows in the preferred embodiment to encode a pulse in the vertical interval of a video signal before the video signal is delayed. The encoded pulse is recovered from the vertical interval of the delayed video signal. Various methods responsive to the encoded pulse or the timing thereof for the undelayed video and the encoded pulse recovered from the vertical interval of the delayed video are shown which enable the determination of the delay, or the control of a corresponding audio delay.
U.S. Pat. No. 5,530,483 by the present inventor shows determining video delay by sampling an image of the undelayed video and sampling images, including the same image of the delayed version of the video and comparing the samples of the undelayed image to the samples of the delayed images until a match is found indicating that the undelayed image in delayed form is being compared. The time lapse between the sampling of the undelayed image, and the finding of the matching delayed image is used as a measure of video signal delay.
U.S. Pat. No. 5,572,261 by the present inventor shows a method of determining the relative delay between an audio and a video signal by inspecting the video for a speaker's mouth and determining various mouth patterns of movement which correspond to sounds which are present in the audio signal. The time relationship between a mouth pattern which creates a sound and the occurrence of that sound in the audio is used as a measure of audio to video timing.
U.S. Pat. No. 5,751,368, a CIP of U.S. Pat. No. 5,530,483 shows the use of comparing samples of relatively delayed and undelayed versions of video signal images for determining the delay of multiple signals.
Applicant incorporates all of the above prior art patents herein as fully as if they were set forth in their entirety for the purposes of enabling one of ordinary skill in the art to practice the present invention in so far as the present invention utilizes many elements which are taught therein. In particular, attention is called to U.S. Pat. No. RE 33,535 and the teachings of generating a timing signal in response to an audio signal, and the comparison of a recovered timing signal and a newly generated timing signal at the receiving site to determine the relative delay therebetween.
The above cited inventions often prove to be less than complete solutions for modern television systems and others which transmit or store a plurality of signals for various reasons including for example those problems recited below. In particular, the current transmission of MPEG compressed television signals has proven to have particular difficulty in maintaining audio to video synchronization, and the prior art has particular problems in dealing with such.
U.S. Pat. No. 4,313,135 compares relatively undelayed and delayed versions of the same video signal to provide a delay signal. This method requires connection between the undelayed site and the delayed site and is unsuitable for environments where the two sites are some distance apart. For example where television programs are sent from the network in New York to the affiliate station in Los Angeles such system is impractical because it would require the undelayed video to be sent to the delayed video site in Los Angeles without appreciable delay, somewhat of an oxymoron when the problem is that the transmission itself creates the delay which is part of the problem. A problem also occurs with large time delays such as occur with storage such as by recording since by definition the video is to be stored and the undelayed version is not available upon the subsequent playback or recall of the stored video.
U.S. Pat. Nos. 4,665,431 and 5,675,388 show transmitting an audio signal as part of a video signal so that both the audio and video signals experience the same transmission delays thus maintaining the relative synchronization therebetween. This method is expensive for multiple audio signals, and the digital version has proven difficult to implement when used in conjunction with video compression such as MPEG.
U.S. Reissue Pat. No. RE 33,535 corresponding to U.S. Pat. No. 4,703,355 shows in the preferred embodiment to encode a timing signal in the vertical interval of a video signal and transmitting the video signal with the timing signal. Unfortunately many systems strip out and fail to transmit the entire vertical interval of the video signal thus causing the timing signal to be lost. It is suggested to put a timing signal in the audio signal, which is continuous thus reducing the probability of losing the timing signal. Unfortunately it is difficult and expensive to put a timing signal in the audio signal in a manner which ensures that it will be carried with the audio signal, is easy to detect, and is inaudible to the most discerning listener.
U.S. Pat. No. 5,202,761 shows to encode a pulse in the vertical interval of a video signal before the video signal is delayed. This method also suffers when the vertical interval is lost.
U.S. Pat. No. 5,530,483 shows determining video delay by a method which includes sampling an image of the undelayed video. This method also requires the undelayed video, or at least the samples of the undelayed video, be available at the receiving location without significant delay. Like the '135 patent above this method is unsuitable for long distance transmission or time delays resulting from storage.
U.S. Pat. No. 5,572,261 shows a method of determining the relative delay between an audio and a video signal by inspecting the video for particular sound generating events such as a particular movement of a speaker's mouth and determining various mouth patterns of movement which correspond to sounds which are present in the audio signal. The time relationship between a video event such as mouth pattern which creates a sound and the occurrence of that sound in the audio is used as a measure of audio to video timing. This method requires a significant amount of audio and video signal processing to operate.
U.S. Pat. No. 5,751,368, a CIP of U.S. Pat. No. 5,530,483 shows the use of comparing samples of relatively delayed and undelayed versions of video signal images for determining the delay of multiple signals. Like the '483 patent the '368 patent needs for the undelayed video or at least samples thereof to be present at the receiving location.
U.S. Pat. No. 6,330,033 and Division U.S. Pat. No. 6,351,281 show a delay tracker for a signal processing system, where the delay tracker utilizes a special code or pulse associated with the tracked signal with the system including a pulse detector later recognizing the special code or pulse in order to identify such signal and ascertain any delays associated with the signal including possible resynchronization of associated signals. In the preferred embodiment the invention is utilized with video and audio signals to measure or maintain lip sync. The delay tracker is associated with the video signal in a manner that it will be carried through the processing that it is expected to receive. In one particular example the tracker which is associated with the video signal is generated in response to certain artifacts or characteristics already present in the audio signal.
The instant invention provides for improvements in the field of transmitting and storing multiple electronic signals where synchronization of the signals is of concern, for example related to U.S. Pat. Nos. 6,330,033 and 6,351,281.
Attempts have been made to add various timing related signals in television program streams in order to maintain audio to video synchronization. In particular in MPEG systems control signals such as time stamps are utilized. Unfortunately the inclusion of these signals does not guarantee proper audio to video synchronization at the receive side output of the system for a variety of reasons, including the fact that there are significant video delays which occur which cannot be tracked by the time stamps.
BRIEF SUMMARY OF THE INVENTION
It is an object of the invention to provide a method for measuring or maintaining the relative delay of a plurality of signals which are passed through subsequent processing.
It is another object of the invention to provide a method of generating a marker in response to a second signal which marker may be associated with a first signal in a fashion that said marker is carried with said first signal through processing of said first signal.
It is still another object of the invention to provide a method of responding to a marker which has been associated with a first signal and a marker which is provided in response to a second signal whereby said markers may be utilized to determine the relative delay between said first and second signals.
It is a further object of the invention to provide a marker in response to a signal wherein said marker indicates the occurrence of particular characteristics of said signal.
It is a still further object of the invention to provide a system of measuring the relative delay between an audio and a video signal in a television system wherein the audio and video signals are subject to differing processing which creates unequal delays in said signals.
It is yet still a further object of the invention to provide a method of marking a first signal which may be a video signal to allow relative delay measurement of said first signal and a second signal which may be an audio signal after they have been processed, including use of a marker generator responsive to the second signal to generate a marker upon the occurrence of one or more particular characteristics of the audio, associating the marker with the video signal in a fashion such that the marker will be carried with the video signal and not be adversely affected by the subsequent processing thereof.
It is yet still another object of the invention to provide a relative delay measurement system for measuring the relative delay between a plurality of signals including a first signal which is a video signal and second signal which is an audio signal which signals experience unequal delays due to processing thereof, the invention including use of a marker generator responsive to the audio signal to generate a marker upon the occurrence of one or more particular characteristics of the audio, associating the marker with the video signal in a fashion such that the marker will be carried with the video signal but not be adversely affected by the subsequent processing thereof, responding to the marker with the video signal after the processing to generate a first delayed marker; generating a second delayed marker in response to the processed audio signal, comparing the relative timing of the first and second delayed markers to determine the relative timing between the processed audio and processed video signal.
The preferred embodiment of the invention may be used with a television signal. At the transmitting location a marker is generated in response to the audio signal and is associated with the video signal such that the marker is carried with the video signal in a fashion such that it will not be lost or adversely affected by the expected processing of the video signal. The audio signal and the marker associated video signal are stored, transmitted and/or processed and made available at a later time thus becoming delayed video and audio signals. A first delayed marker is recovered from the delayed video signal and a corresponding second delayed marker is generated from the delayed audio signal, with the two delayed markers compared to determine the relative delay therebetween. This relative delay between these markers is responsive to and is a measure of the delay between the delayed video signal and delayed audio signal.
Somewhat simplistically stated, the preferred embodiment of the invention operates by generation of the marker at the transmit section, which may be thought of a marking the video at the time of the occurrence of a known event in the audio signal. The time marker is associated with the video signal such that it is carried in time with the video signal for all of the processing which the video signal is to experience. After the video signal processing and any audio signal processing, the same event in the audio is again marked in time, and the previously marked time (relative to the video) is recovered or flagged in the received video. Since it is known that the audio event and the marking of the video occurred (substantially) simultaneously at the transmit location, the displacement between those events at the receive location is a measure of the audio to video timing error, or the relative delay therebetween.
Generally, the present invention teaches measuring the relative delay between a plurality of signals which have suffered differing delays due to transmission, storage or other processing. The preferred embodiment of the invention includes the use of a marker which is generated in response to a second signal and combined with a first signal in a manner which ensures that the marker will not be lost in the expected processing of the first signal. Subsequently a first delayed marker is generated in response to the marker associated with or recovered from the first signal, and a second delayed marker is generated from the second signal. The first delayed marker and second delayed marker are compared to determine a measure of the relative timing or delay between said first signal and said second signal at said subsequent time.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a block diagram of the preferred embodiment of the invention as used with a television audio and video signal.
FIG. 2 shows a block diagram of the marker generator 3 and 13 of the preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1 the preferred embodiment of the invention which is given by way of example, a video signal 1 and an audio signal 2 are present at what will be referred to as the transmit location. Either or both the video and audio signals may be in analog or digital, compressed or uncompressed form, the many variations and versions of which are well known in the art. Further. while the preferred embodiment is shown in respect to one video and one audio signal, it will be appreciated from the teachings herein that the invention may be utilized and practiced with multiple video and/or audio signals. In particular, by way of example the invention may be practiced with video and stereo (2 channel), surround (4+channel) or 5.1 channel audio systems as are contemplated for the new U.S. digital and HDTV transmission standards. It is also noted that the components of the invention may be implemented by analog, digital or software means or combinations thereof.
A marker generator 3 is responsive to the audio signal, and may be responsive to the video signal as indicated by the dashed line. In response to detecting the occurrence of one or more particular feature or characteristic of the audio signal generates a marker. One of ordinary skill in the art will recognize that element 44 of U.S. Pat. No. RE 33,535 may be utilized as element 3 herein. Other constructions and operations of 3 will also be known to one of ordinary skill from the present teachings. The particular features, characteristics, occurrences or other event in the audio signal which will result in the marker, will be referred to hereinafter as occurrences and the marker in its various forms will sometimes be referred to simply as a marker, one of ordinary skill understanding from the context and the teachings herein the specificity of the form or forms being referred to.
The marker from 3 is associated with the video signal 1 in a marker associator 4 . One of ordinary skill in the art will recognize that element 10 of the U.S. Pat. No. 6,330,033 specification can be used for element 4 herein. Other constructions and operations of 4 will also be known to one of ordinary skill from the present teachings. The marker is preferred to be associated with the video signal in a fashion that the marker will not be lost, corrupted or modified beyond use by subsequent processing of the video signal. In particular it is preferred to associate the marker with the video signal by including the marker within the active picture information of the video signal in one of the manners disclosed in detail in the U.S. Pat. No. 6,330,033 specification. Consequently the marker may take on a form of active video, whatever form the video may be in.
Alternatively, the marker may be associated with the video signal by being encoded in the active video in a relatively invisible fashion by utilizing one of the various watermark techniques which are well known in the art. Watermarking is well known as a method of encoding the ownership or source of images in the image itself in an invisible, yet recoverable fashion. In particular known watermarking techniques allow the watermark to be recovered after the image has suffered severe processing of many different types. Such watermarking allows reliable and secure recovery of the marker after significant subsequent processing of the active portion of the video signal. By way of example, the marker of the present invention may be added to the watermark, or replace a portion or the entirety of the watermark, or the watermarking technique simply adapted for use with the marker. It is believed that this use of watermarking techniques to associate marker signals with video signals for audio to video timing purposes is novel and previously unknown to those in the art. Other methods of associating the marker with the video signal will be known to those of ordinary skill in the art from the teachings herein.
The video signal with the marker is output from 4 and coupled to the video encoder 5 . The video encoder 5 is used by way of example in the present description to represent that part of the subsequent video processing which may take place at the transmitting side of the system. For example, the video encoder may include MPEG preprocessing and compression circuits. Similarly, the audio 2 is coupled to an audio encoder 6 which is used by way of example in the present description to represent the audio processing which may take place at the transmitting side of the system. For example, the audio encoder may include an MPEG compression circuit. The compressed video and audio signals are combined by video and audio combiner 7 and the combined signals are coupled to the transmission channel 8 .
The audio and video signals from the transmission channel 8 are coupled to a video and audio separator 9 which separates the audio and video signal components of the transmitted signal(s). The audio and video signals are coupled to audio decoder 11 and video decoder 10 respectively, where they are decoded back into decoded audio 17 and decoded video 16 respectively.
At the receiving side, marker separator 12 responds to the marker which was previously combined in the video signal by 4 to provide a first delayed marker to 14 . The first delayed marker may be in the same form or different form as the marker which is associated with the video. It is preferred that the marker be recovered from the video and provided as the first delayed marker, however it is sufficient to merely detect the presence of the marker in the video and generate a first delayed marker in response thereto. One of ordinary skill in the art will recognize that element 40 of the U.S. Pat. No. 6,330,033 specification may be utilized for element 12 herein. Other constructions and operations of 12 will also be known to one of ordinary skill from the present teachings.
Also at the receiving side, another marker generator 13 , similar to 3 , generates a second delayed marker in response to the same audio signal occurrences in the receive section audio from 11 as did the marker generator 3 on the transmit section in response to audio signal 2 . Marker generator 13 may also be responsive to video in a fashion as previously described for 3 as shown by 19 . The second delayed marker generated by 13 need not be in the same form as the marker generated by 3 , but is preferred to be in the same form as the first delayed marker provided by 12 .
The first and second delayed markers from 12 and 13 are coupled to the relative timing comparison 14 . The relative timing comparison is responsive to these delayed markers to determine the timing between corresponding pairs thereof to determine the relative timing between them. In other words the relative timing comparison 14 determines the delay 15 of the later of the two delayed markers relative to the earlier, indicating both the magnitude of the delay and which signal is more delayed. One of ordinary skill in the art will recognize from the teachings herein that relative timing comparison 14 may operate as described with respect to element 50 of the U.S. Pat. No. 6,330,033 specification. Other constructions and operations of 14 will also be known to one of ordinary skill from the present teachings.
Since the first delayed marker from 12 experiences the delay of the video signal 1 , and the second delayed marker from 13 experiences the delay of the audio signal 2 in their respective paths from the input of the transmit section to the output of the receive section, signal 15 is a measure of the relative delay of audio 17 and video 16 at the output of the receive section.
The relative delay 15 may be utilized for all of the uses and reasons set forth in the U.S. Pat. No. 6,330,033 specification. In particular note that the relative delay signal 15 is useful in itself as a measure of system quality. Relative delay signal 15 may be utilized to control a delay to delay the earlier of 16 or 17 to place the two signals into synchronization. Relative delay signal 15 may also be utilized to control a delay which is incorporated into 10 or 11 or both (or elsewhere in the system) to control the delay of the earlier of the audio or video from 9 to maintain the two signals 16 and 17 in synchronization. Relative delay signal 15 may also be utilized for other purposes, for example as feedback to control the operation of encoder 5 or 6 or decoder 10 or 11 to minimize or otherwise optimize delay or encoding and decoding of audio or video.
Various different embodiments of the invention herein described will be apparent to one of ordinary skill in the art from the teachings herein. As an example, the marker generator 3 may be responsive to the video signal as shown by 18 in order to relate the marker to the video signal, for example to properly locate the marker for combination with the video signal or to relate the particular feature(s) of the audio signal to timing of the video signal. In particular, it is desired that the marker represent whether or not the particular features occurred in the audio signal during the one or more frame or field immediately prior to the marker being combined with the video and going back to the time when the immediately previous marker was combined.
The marker is preferred to be a binary signal which indicates that one or more of a number of particular occurrences of the audio which has taken place during the preceding field(s), or is currently taking place. For example, an 8 bit binary signal may be utilized with different numbers corresponding to different occurrences or features. In the preferred embodiment, it is preferred that the audio signal, which in the present example is assumed to have a bandwidth of 10 Hz to 20,000 Hz be broken up into 8 different frequency bands by bandpass filtering. Each bit of the 8 bit number corresponds to the presence of audio frequencies within a particular band having energy within known levels and for known time durations. For example, if no such frequencies are present, the binary number 0 (0000 0000) results. If the lowest frequencies occur, the binary number 1 (0000 0001) results. If the next highest frequency occurs the binary number 2 (0000 0010) results. If both the lowest and next highest occur a 3 results. If all frequencies occur the binary number 255 (1111 1111) results. The binary number is the marker which is combined with the video.
It is important to note that by associating the marker with the video signal in the fashion of including it in the active video portion of the signal that the marker will not be lost when all of the sync and blanking (or line, field and other ancillary signals if in digital form) are removed from the video signal such as is done as part of the MPEG encoding process. The association of the marker directly with the image carried by the video signal essentially guarantees that no matter what processing, stripping or modification of ancillary portions of the video signal occurs, in either analog or digital form, or conversion of scanning rates, or adjustment of usual video parameters such as black, brightness and chroma, that the marker will still be detectable at the receive location.
The transmission channel 8 is utilized in the present example to represent any common or independent use or processing of the video signal 1 and audio signal 2 which may cause or result in unequal delays which lead to timing difficulties. Examples of such uses include transmission, storage and further processing, and in particular include storage and/or transmitting of MPEG encoded audio and video signals.
Also it may be noted that marker generators 3 and 13 may respond to video in other forms, or from other parts of the system, or may respond to other signals, for example a genlock reference, in order to achieve proper operation and timing of the marker generator.
It may be noted that the use of the video encoder 5 , audio encoder 6 and video and audio combiner 7 is given by way of example, as is usual for MPEG compression and transmission systems which are commonly used in today's television systems. The invention is not limited to the use of such elements however and one of ordinary skill in the art will know how to practice the generation of the marker and the associating of the marker with the video signal in other systems from the present teachings. The combined marker and video signal from 4 and the audio signal 2 may very well be utilized in practicing the present invention without the added elements 5 - 7 .
It will be understood that in the present example the elements 9 , 10 and 11 are the receiving side elements complimentary to corresponding transmitting side elements 7 , 5 and 6 respectively. As with 5 , 6 and 7 , elements 9 , 10 and 11 are not required to practice the invention. In particular, video from 4 may be coupled, via a transmission channel directly to element 12 and become video signal 16 . Similarly, audio signal 2 may be coupled via the same or different transmission channel directly to 13 and become audio signal 17 .
In the situation where the transmission channel includes storage of the audio and video signals, and storage and recovery is not performed simultaneously, it is noted that a single marker generator 3 may perform the function of 3 upon the storing of the signals and subsequently perform the function of 13 upon the recovery of the stored signals. Other sharing of circuitry between storing and recovery functions may also be had given the assumption that both are not performed simultaneously.
FIG. 2 shows the preferred form of the marker generator 3 and 13 of the preferred embodiment of the invention as used with television audio signals. Audio signal 20 which may correspond to 2 or the output of 11 in FIG. 1 is coupled to a bank of 8 bandpass filters 21 a - h which are configured to pass only audio within a range of frequencies as is well known in the art. The output of each bandpass filter is coupled to a comparator 22 a - h respectively. The comparators include hysteresis or other threshold(s) and bipolar response characteristic so that if the positive or negative half cycle of bandpassed audio out of the bandpass filter exceeds a threshold amount set by the hysteresis, the output of the comparator is activated. Each comparator output is respectively coupled to a timing duration circuit 23 a - h . Each timing duration circuit also receives a reset signal from the timing circuit 26 . The timing circuit 26 provides signals to the parallel to serial converter 24 in addition to the reset signal provided to the timing duration circuits 23 . Once the timing duration circuit is reset, it inspects the output signal from its respective comparator 22 . If the output signal from 22 is activated for an established time duration indicating the presence of audio frequencies within the corresponding bandpass filter range, the timing duration circuit sets its output active and holds it active until the next reset signal. The outputs of all of the timing duration circuits 23 are simultaneously latched into the parallel to serial circuit 24 upon command from the timing circuit 26 and shortly thereafter the reset signal to 23 is generated. Also shortly after latching, the bits latched into 24 are caused to be output in serial fashion as marker 25 . The net effect of the circuitry is to set a bit of the timing signal active corresponding to each of the bandpass audio frequencies which was present during the time period from one reset signal to the next, which corresponds to the time period from the generation of one marker to the next. The timing circuit 26 is responsive to the video signal to set the desired time period between markers, as well as to time the output of the marker 25 so that it is associated with the video signal at the correct time. This action will ensure that the marker is placed at the desired position in the video signal.
The bandpass filters are preferred to be selected to provide frequent outputs with the expected types of audio signals. For commercial television audio signals it has been found that bandpass filters with center frequencies of 25, 50, 150, 400, 1000, 2500, 6000, 15000 Hz and skirts of 6 dB per octave work well. Other center frequencies and bandwidths may be chosen, and the number of filters changed, to facilitate expected audio signal frequency content. Ideally the frequencies would be chosen such that the lowest frequency filter has an output which is active or makes a change of state only once per period of the maximum expected delay differential of the audio and video signal. Alternatively, other audio characteristics may be relied on in the place of, or in addition to, the detection of energy at particular frequencies as described in respect to the preferred embodiment. Examples include, but are not limited to, impulse characteristics, amplitude characteristics, relationships between different frequency energies, relationships among and between different audio channels.
Another example of alternate audio characteristics which may be utilized for the marker is the particular audio sonic characteristics which are relied on for the audio compression. Because these characteristics are already detected in the compression circuitry the present invention may share circuitry thus resulting in lowered cost. Other sharing of circuitry with other functions may be possible depending on the particular signals and environment with which the invention is used.
While it has been described to utilize the marker generator with one audio signal in the preferred embodiment, it will be understood that multiple audio signals may be accommodated, with each having a corresponding marker which is associated with the video. Alternatively a plurality of audio signals may be used to generate a lesser number or even one marker by various techniques which include combining the plurality of audio signals before coupling to the marker generator, or by combining various markers each responsive to one or a small number of audio signals with the various markers being combined into a smaller number or a single master marker.
It may be noted that many audio ICs which are used for audio graphic equalizer functions contain bandpass filters which may be adapted to use in this invention. Of course it is possible to implement the various elements of the marker generator, as well as the rest of the invention, in analog or digital hardware, or software/hardware or combinations thereof.
It will be noted that the present description of the preferred embodiment of the invention is given by way of example. In particular the diagrams of the preferred embodiment are presented as block diagrams and do not show in detail circuitry and cooperation which would be known to those of ordinary skill in the art from the teachings herein without undue experimentation. By way of example it is noted that where one signal line is shown in the block diagram that multiple signals may in actuality be coupled between one block and another, and although separate functional blocks are shown it will be known to make different combinations, arrangements and implementations in order to share elements therebetween and reduce costs. It is also noted that various terms used in the specification, including generator, combiner, encoder, separator, decoder and comparison, and their various tenses are intended to have broader meaning than that ordinarily ascribed thereto with respect to circuit elements, and are intended to cover not only the commonly understood element but the equivalent operation or function as implemented by other circuitry or software/hardware combinations. One of ordinary skill in the art will know to resort to various changes and modifications to the invention as described as well the combination of the invention with other features functions and/or inventive concepts in order to accommodate the use of the invention with particular forms of signals and otherwise to practice the invention in a fashion which is optimized for particular application without departing from the spirit and scope of the invention as hereafter claimed. | An invention for measuring, maintaining and correcting synchronization between signals which suffer varying relative delays during transmission and/or storage is shown. The present invention teaches measuring the relative delay between a plurality of signals which have suffered differing delays due to transmission, storage or other processing. The preferred embodiment of the invention includes the use of a marker which is generated in response to a second signal and combined with a first signal in a manner which ensures that the marker will not be lost in the expected processing of the first signal. Subsequently a first delayed marker is generated in response to the marker associated with or recovered from the first signal, and a second delayed marker is generated from the second signal. The first delayed marker and second delayed marker are compared to determine a measure of the relative timing or delay between said first signal and said second signal at said subsequent time. | Identify the most important aspect in the document and summarize the concept accordingly. | [
"This application is a Division of application Ser.",
"No. 14/170,786 filed Feb. 3, 2014 and issued as U.S. Pat. No. 9,071,723 on Jun. 30, 2012, which is a Division of application Ser.",
"No. 13/347,633 filed Jan. 10, 2012 and issued as U.S. Pat. No. 8,810,659 on Aug. 19, 2014, which is a Division of application Ser.",
"No. 12/471,127 filed May 22, 2009 and issued as U.S. Pat. No. 8,159,610 on Apr. 17, 2012, which is a Division of Ser.",
"No. 10/894,746 filed Jul. 19, 2004 and issued as U.S. Pat. No. 7,710,499 on May 4, 2010 which is a Division of application Ser.",
"No. 09/545,529 filed Apr. 7, 2000 and issued as U.S. Pat. No. 6,836,295 on Dec. 28, 2004 all of which are incorporated herein by reference as fully as if they had been set out in detail and to which priority is claimed.",
"Application Ser.",
"No. 09/545,529 is in turn a Continuation-in-part of application Ser.",
"No. 09/119,524 filed Jul. 21, 1998 and issued as U.S. Pat. No. 6,351,281 on Feb. 26, 2002 which is a Division of application Ser.",
"No. 08/620,126 filed Mar. 21, 1996 which issued as U.S. Pat. No. 6,330,033 on Dec. 11, 2001 which claims benefit of Provisional Application 60/008,309 filed Dec. 7, 1995.",
"No priority to application Ser.",
"No. 09/119,524, U.S. Pat. No. 6,351,281, application Ser.",
"No. 08/620,126, U.S. Pat. No. 6,330,033 or Application 60/008,309 is claimed, but which are incorporated herein by reference, in respect to their prior art teachings.",
"The examiner's attention is called to incorrectly published U.S. Pat. No. 5,847,769 which is related to the present application by virtue of common application Ser.",
"No. 08/620,126.",
"The '769 patent was withdrawn from issue.",
"Despite the fact of the patent being withdrawn from issue it was nevertheless published by the Patent Office.",
"Applicant brings this withdrawn patent to the attention of the examiner out of applicant's duty of candor.",
"BACKGROUND OF THE INVENTION The invention relates to measuring, maintaining and correcting synchronization between two signals which suffer varying relative delays during transmission and/or storage, and in particular to measuring the relative delay between multiple audio signals and an associated video signal of a television type program which is compressed via MPEG or other compression method for transmission and/or storage.",
"Field of the Invention The present invention relates to the field of transmitting and storing multiple electronic signals where synchronization of the signals is of concern.",
"When such transmitting and storing are of a nature which makes the corresponding receiving and recovering of said signals subject to timing errors resulting from differing amounts of processing delays the present invention is useful in measuring the relative timing errors or delays between signals with such delay measurement being used as a meter of quality of the transmitting and storing and for maintaining or correction of relative delays between such signals.",
"Description of Related Prior Art It is known in the television signal transmission field to measure and correct audio to video timing errors by measuring the delay which a video signal experiences and using that measurement to delay a companion audio signal by a corresponding amount.",
"U.S. Pat. No. 4,313,135 by the present inventor shows to compare relatively undelayed and delayed versions of the same video signal to provide a delay signal responsive to the delay thereof and to couple that delay signal to a variable audio delay to cause the audio delay to delay the companion audio signal by a corresponding amount.",
"U.S. Pat. Nos. 4,665,431 and 5,675,388 by the present inventor show transmitting an audio signal as part of a video signal so that both the audio and video signals experience the same transmission delays thus maintaining the relative synchronization therebetween.",
"U.S. Reissue Pat. No. RE 33,535 corresponding to U.S. Pat. No. 4,703,355 shows in the preferred embodiment to encode in the vertical interval of a video signal, a timing signal derived from an audio signal and transmitting the combined video signal and the audio signal.",
"At the receiving location the timing signal is recovered from the video signal and a new timing signal is generated from the received audio signal.",
"The two timing signals are compared at the receiving location to determine the relative delay between the timing signal recovered from the video and the newly generated timing signal, thus determining the relative delay between the video and audio signals at the receive location.",
"It is also suggested to put a timing signal in the audio signal.",
"U.S. Pat. No. 5,202,761 by the present inventor shows in the preferred embodiment to encode a pulse in the vertical interval of a video signal before the video signal is delayed.",
"The encoded pulse is recovered from the vertical interval of the delayed video signal.",
"Various methods responsive to the encoded pulse or the timing thereof for the undelayed video and the encoded pulse recovered from the vertical interval of the delayed video are shown which enable the determination of the delay, or the control of a corresponding audio delay.",
"U.S. Pat. No. 5,530,483 by the present inventor shows determining video delay by sampling an image of the undelayed video and sampling images, including the same image of the delayed version of the video and comparing the samples of the undelayed image to the samples of the delayed images until a match is found indicating that the undelayed image in delayed form is being compared.",
"The time lapse between the sampling of the undelayed image, and the finding of the matching delayed image is used as a measure of video signal delay.",
"U.S. Pat. No. 5,572,261 by the present inventor shows a method of determining the relative delay between an audio and a video signal by inspecting the video for a speaker's mouth and determining various mouth patterns of movement which correspond to sounds which are present in the audio signal.",
"The time relationship between a mouth pattern which creates a sound and the occurrence of that sound in the audio is used as a measure of audio to video timing.",
"U.S. Pat. No. 5,751,368, a CIP of U.S. Pat. No. 5,530,483 shows the use of comparing samples of relatively delayed and undelayed versions of video signal images for determining the delay of multiple signals.",
"Applicant incorporates all of the above prior art patents herein as fully as if they were set forth in their entirety for the purposes of enabling one of ordinary skill in the art to practice the present invention in so far as the present invention utilizes many elements which are taught therein.",
"In particular, attention is called to U.S. Pat. No. RE 33,535 and the teachings of generating a timing signal in response to an audio signal, and the comparison of a recovered timing signal and a newly generated timing signal at the receiving site to determine the relative delay therebetween.",
"The above cited inventions often prove to be less than complete solutions for modern television systems and others which transmit or store a plurality of signals for various reasons including for example those problems recited below.",
"In particular, the current transmission of MPEG compressed television signals has proven to have particular difficulty in maintaining audio to video synchronization, and the prior art has particular problems in dealing with such.",
"U.S. Pat. No. 4,313,135 compares relatively undelayed and delayed versions of the same video signal to provide a delay signal.",
"This method requires connection between the undelayed site and the delayed site and is unsuitable for environments where the two sites are some distance apart.",
"For example where television programs are sent from the network in New York to the affiliate station in Los Angeles such system is impractical because it would require the undelayed video to be sent to the delayed video site in Los Angeles without appreciable delay, somewhat of an oxymoron when the problem is that the transmission itself creates the delay which is part of the problem.",
"A problem also occurs with large time delays such as occur with storage such as by recording since by definition the video is to be stored and the undelayed version is not available upon the subsequent playback or recall of the stored video.",
"U.S. Pat. Nos. 4,665,431 and 5,675,388 show transmitting an audio signal as part of a video signal so that both the audio and video signals experience the same transmission delays thus maintaining the relative synchronization therebetween.",
"This method is expensive for multiple audio signals, and the digital version has proven difficult to implement when used in conjunction with video compression such as MPEG.",
"U.S. Reissue Pat. No. RE 33,535 corresponding to U.S. Pat. No. 4,703,355 shows in the preferred embodiment to encode a timing signal in the vertical interval of a video signal and transmitting the video signal with the timing signal.",
"Unfortunately many systems strip out and fail to transmit the entire vertical interval of the video signal thus causing the timing signal to be lost.",
"It is suggested to put a timing signal in the audio signal, which is continuous thus reducing the probability of losing the timing signal.",
"Unfortunately it is difficult and expensive to put a timing signal in the audio signal in a manner which ensures that it will be carried with the audio signal, is easy to detect, and is inaudible to the most discerning listener.",
"U.S. Pat. No. 5,202,761 shows to encode a pulse in the vertical interval of a video signal before the video signal is delayed.",
"This method also suffers when the vertical interval is lost.",
"U.S. Pat. No. 5,530,483 shows determining video delay by a method which includes sampling an image of the undelayed video.",
"This method also requires the undelayed video, or at least the samples of the undelayed video, be available at the receiving location without significant delay.",
"Like the '135 patent above this method is unsuitable for long distance transmission or time delays resulting from storage.",
"U.S. Pat. No. 5,572,261 shows a method of determining the relative delay between an audio and a video signal by inspecting the video for particular sound generating events such as a particular movement of a speaker's mouth and determining various mouth patterns of movement which correspond to sounds which are present in the audio signal.",
"The time relationship between a video event such as mouth pattern which creates a sound and the occurrence of that sound in the audio is used as a measure of audio to video timing.",
"This method requires a significant amount of audio and video signal processing to operate.",
"U.S. Pat. No. 5,751,368, a CIP of U.S. Pat. No. 5,530,483 shows the use of comparing samples of relatively delayed and undelayed versions of video signal images for determining the delay of multiple signals.",
"Like the '483 patent the '368 patent needs for the undelayed video or at least samples thereof to be present at the receiving location.",
"U.S. Pat. No. 6,330,033 and Division U.S. Pat. No. 6,351,281 show a delay tracker for a signal processing system, where the delay tracker utilizes a special code or pulse associated with the tracked signal with the system including a pulse detector later recognizing the special code or pulse in order to identify such signal and ascertain any delays associated with the signal including possible resynchronization of associated signals.",
"In the preferred embodiment the invention is utilized with video and audio signals to measure or maintain lip sync.",
"The delay tracker is associated with the video signal in a manner that it will be carried through the processing that it is expected to receive.",
"In one particular example the tracker which is associated with the video signal is generated in response to certain artifacts or characteristics already present in the audio signal.",
"The instant invention provides for improvements in the field of transmitting and storing multiple electronic signals where synchronization of the signals is of concern, for example related to U.S. Pat. Nos. 6,330,033 and 6,351,281.",
"Attempts have been made to add various timing related signals in television program streams in order to maintain audio to video synchronization.",
"In particular in MPEG systems control signals such as time stamps are utilized.",
"Unfortunately the inclusion of these signals does not guarantee proper audio to video synchronization at the receive side output of the system for a variety of reasons, including the fact that there are significant video delays which occur which cannot be tracked by the time stamps.",
"BRIEF SUMMARY OF THE INVENTION It is an object of the invention to provide a method for measuring or maintaining the relative delay of a plurality of signals which are passed through subsequent processing.",
"It is another object of the invention to provide a method of generating a marker in response to a second signal which marker may be associated with a first signal in a fashion that said marker is carried with said first signal through processing of said first signal.",
"It is still another object of the invention to provide a method of responding to a marker which has been associated with a first signal and a marker which is provided in response to a second signal whereby said markers may be utilized to determine the relative delay between said first and second signals.",
"It is a further object of the invention to provide a marker in response to a signal wherein said marker indicates the occurrence of particular characteristics of said signal.",
"It is a still further object of the invention to provide a system of measuring the relative delay between an audio and a video signal in a television system wherein the audio and video signals are subject to differing processing which creates unequal delays in said signals.",
"It is yet still a further object of the invention to provide a method of marking a first signal which may be a video signal to allow relative delay measurement of said first signal and a second signal which may be an audio signal after they have been processed, including use of a marker generator responsive to the second signal to generate a marker upon the occurrence of one or more particular characteristics of the audio, associating the marker with the video signal in a fashion such that the marker will be carried with the video signal and not be adversely affected by the subsequent processing thereof.",
"It is yet still another object of the invention to provide a relative delay measurement system for measuring the relative delay between a plurality of signals including a first signal which is a video signal and second signal which is an audio signal which signals experience unequal delays due to processing thereof, the invention including use of a marker generator responsive to the audio signal to generate a marker upon the occurrence of one or more particular characteristics of the audio, associating the marker with the video signal in a fashion such that the marker will be carried with the video signal but not be adversely affected by the subsequent processing thereof, responding to the marker with the video signal after the processing to generate a first delayed marker;",
"generating a second delayed marker in response to the processed audio signal, comparing the relative timing of the first and second delayed markers to determine the relative timing between the processed audio and processed video signal.",
"The preferred embodiment of the invention may be used with a television signal.",
"At the transmitting location a marker is generated in response to the audio signal and is associated with the video signal such that the marker is carried with the video signal in a fashion such that it will not be lost or adversely affected by the expected processing of the video signal.",
"The audio signal and the marker associated video signal are stored, transmitted and/or processed and made available at a later time thus becoming delayed video and audio signals.",
"A first delayed marker is recovered from the delayed video signal and a corresponding second delayed marker is generated from the delayed audio signal, with the two delayed markers compared to determine the relative delay therebetween.",
"This relative delay between these markers is responsive to and is a measure of the delay between the delayed video signal and delayed audio signal.",
"Somewhat simplistically stated, the preferred embodiment of the invention operates by generation of the marker at the transmit section, which may be thought of a marking the video at the time of the occurrence of a known event in the audio signal.",
"The time marker is associated with the video signal such that it is carried in time with the video signal for all of the processing which the video signal is to experience.",
"After the video signal processing and any audio signal processing, the same event in the audio is again marked in time, and the previously marked time (relative to the video) is recovered or flagged in the received video.",
"Since it is known that the audio event and the marking of the video occurred (substantially) simultaneously at the transmit location, the displacement between those events at the receive location is a measure of the audio to video timing error, or the relative delay therebetween.",
"Generally, the present invention teaches measuring the relative delay between a plurality of signals which have suffered differing delays due to transmission, storage or other processing.",
"The preferred embodiment of the invention includes the use of a marker which is generated in response to a second signal and combined with a first signal in a manner which ensures that the marker will not be lost in the expected processing of the first signal.",
"Subsequently a first delayed marker is generated in response to the marker associated with or recovered from the first signal, and a second delayed marker is generated from the second signal.",
"The first delayed marker and second delayed marker are compared to determine a measure of the relative timing or delay between said first signal and said second signal at said subsequent time.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a block diagram of the preferred embodiment of the invention as used with a television audio and video signal.",
"FIG. 2 shows a block diagram of the marker generator 3 and 13 of the preferred embodiment of the invention.",
"DETAILED DESCRIPTION OF THE INVENTION In FIG. 1 the preferred embodiment of the invention which is given by way of example, a video signal 1 and an audio signal 2 are present at what will be referred to as the transmit location.",
"Either or both the video and audio signals may be in analog or digital, compressed or uncompressed form, the many variations and versions of which are well known in the art.",
"Further.",
"while the preferred embodiment is shown in respect to one video and one audio signal, it will be appreciated from the teachings herein that the invention may be utilized and practiced with multiple video and/or audio signals.",
"In particular, by way of example the invention may be practiced with video and stereo (2 channel), surround (4+channel) or 5.1 channel audio systems as are contemplated for the new U.S. digital and HDTV transmission standards.",
"It is also noted that the components of the invention may be implemented by analog, digital or software means or combinations thereof.",
"A marker generator 3 is responsive to the audio signal, and may be responsive to the video signal as indicated by the dashed line.",
"In response to detecting the occurrence of one or more particular feature or characteristic of the audio signal generates a marker.",
"One of ordinary skill in the art will recognize that element 44 of U.S. Pat. No. RE 33,535 may be utilized as element 3 herein.",
"Other constructions and operations of 3 will also be known to one of ordinary skill from the present teachings.",
"The particular features, characteristics, occurrences or other event in the audio signal which will result in the marker, will be referred to hereinafter as occurrences and the marker in its various forms will sometimes be referred to simply as a marker, one of ordinary skill understanding from the context and the teachings herein the specificity of the form or forms being referred to.",
"The marker from 3 is associated with the video signal 1 in a marker associator 4 .",
"One of ordinary skill in the art will recognize that element 10 of the U.S. Pat. No. 6,330,033 specification can be used for element 4 herein.",
"Other constructions and operations of 4 will also be known to one of ordinary skill from the present teachings.",
"The marker is preferred to be associated with the video signal in a fashion that the marker will not be lost, corrupted or modified beyond use by subsequent processing of the video signal.",
"In particular it is preferred to associate the marker with the video signal by including the marker within the active picture information of the video signal in one of the manners disclosed in detail in the U.S. Pat. No. 6,330,033 specification.",
"Consequently the marker may take on a form of active video, whatever form the video may be in.",
"Alternatively, the marker may be associated with the video signal by being encoded in the active video in a relatively invisible fashion by utilizing one of the various watermark techniques which are well known in the art.",
"Watermarking is well known as a method of encoding the ownership or source of images in the image itself in an invisible, yet recoverable fashion.",
"In particular known watermarking techniques allow the watermark to be recovered after the image has suffered severe processing of many different types.",
"Such watermarking allows reliable and secure recovery of the marker after significant subsequent processing of the active portion of the video signal.",
"By way of example, the marker of the present invention may be added to the watermark, or replace a portion or the entirety of the watermark, or the watermarking technique simply adapted for use with the marker.",
"It is believed that this use of watermarking techniques to associate marker signals with video signals for audio to video timing purposes is novel and previously unknown to those in the art.",
"Other methods of associating the marker with the video signal will be known to those of ordinary skill in the art from the teachings herein.",
"The video signal with the marker is output from 4 and coupled to the video encoder 5 .",
"The video encoder 5 is used by way of example in the present description to represent that part of the subsequent video processing which may take place at the transmitting side of the system.",
"For example, the video encoder may include MPEG preprocessing and compression circuits.",
"Similarly, the audio 2 is coupled to an audio encoder 6 which is used by way of example in the present description to represent the audio processing which may take place at the transmitting side of the system.",
"For example, the audio encoder may include an MPEG compression circuit.",
"The compressed video and audio signals are combined by video and audio combiner 7 and the combined signals are coupled to the transmission channel 8 .",
"The audio and video signals from the transmission channel 8 are coupled to a video and audio separator 9 which separates the audio and video signal components of the transmitted signal(s).",
"The audio and video signals are coupled to audio decoder 11 and video decoder 10 respectively, where they are decoded back into decoded audio 17 and decoded video 16 respectively.",
"At the receiving side, marker separator 12 responds to the marker which was previously combined in the video signal by 4 to provide a first delayed marker to 14 .",
"The first delayed marker may be in the same form or different form as the marker which is associated with the video.",
"It is preferred that the marker be recovered from the video and provided as the first delayed marker, however it is sufficient to merely detect the presence of the marker in the video and generate a first delayed marker in response thereto.",
"One of ordinary skill in the art will recognize that element 40 of the U.S. Pat. No. 6,330,033 specification may be utilized for element 12 herein.",
"Other constructions and operations of 12 will also be known to one of ordinary skill from the present teachings.",
"Also at the receiving side, another marker generator 13 , similar to 3 , generates a second delayed marker in response to the same audio signal occurrences in the receive section audio from 11 as did the marker generator 3 on the transmit section in response to audio signal 2 .",
"Marker generator 13 may also be responsive to video in a fashion as previously described for 3 as shown by 19 .",
"The second delayed marker generated by 13 need not be in the same form as the marker generated by 3 , but is preferred to be in the same form as the first delayed marker provided by 12 .",
"The first and second delayed markers from 12 and 13 are coupled to the relative timing comparison 14 .",
"The relative timing comparison is responsive to these delayed markers to determine the timing between corresponding pairs thereof to determine the relative timing between them.",
"In other words the relative timing comparison 14 determines the delay 15 of the later of the two delayed markers relative to the earlier, indicating both the magnitude of the delay and which signal is more delayed.",
"One of ordinary skill in the art will recognize from the teachings herein that relative timing comparison 14 may operate as described with respect to element 50 of the U.S. Pat. No. 6,330,033 specification.",
"Other constructions and operations of 14 will also be known to one of ordinary skill from the present teachings.",
"Since the first delayed marker from 12 experiences the delay of the video signal 1 , and the second delayed marker from 13 experiences the delay of the audio signal 2 in their respective paths from the input of the transmit section to the output of the receive section, signal 15 is a measure of the relative delay of audio 17 and video 16 at the output of the receive section.",
"The relative delay 15 may be utilized for all of the uses and reasons set forth in the U.S. Pat. No. 6,330,033 specification.",
"In particular note that the relative delay signal 15 is useful in itself as a measure of system quality.",
"Relative delay signal 15 may be utilized to control a delay to delay the earlier of 16 or 17 to place the two signals into synchronization.",
"Relative delay signal 15 may also be utilized to control a delay which is incorporated into 10 or 11 or both (or elsewhere in the system) to control the delay of the earlier of the audio or video from 9 to maintain the two signals 16 and 17 in synchronization.",
"Relative delay signal 15 may also be utilized for other purposes, for example as feedback to control the operation of encoder 5 or 6 or decoder 10 or 11 to minimize or otherwise optimize delay or encoding and decoding of audio or video.",
"Various different embodiments of the invention herein described will be apparent to one of ordinary skill in the art from the teachings herein.",
"As an example, the marker generator 3 may be responsive to the video signal as shown by 18 in order to relate the marker to the video signal, for example to properly locate the marker for combination with the video signal or to relate the particular feature(s) of the audio signal to timing of the video signal.",
"In particular, it is desired that the marker represent whether or not the particular features occurred in the audio signal during the one or more frame or field immediately prior to the marker being combined with the video and going back to the time when the immediately previous marker was combined.",
"The marker is preferred to be a binary signal which indicates that one or more of a number of particular occurrences of the audio which has taken place during the preceding field(s), or is currently taking place.",
"For example, an 8 bit binary signal may be utilized with different numbers corresponding to different occurrences or features.",
"In the preferred embodiment, it is preferred that the audio signal, which in the present example is assumed to have a bandwidth of 10 Hz to 20,000 Hz be broken up into 8 different frequency bands by bandpass filtering.",
"Each bit of the 8 bit number corresponds to the presence of audio frequencies within a particular band having energy within known levels and for known time durations.",
"For example, if no such frequencies are present, the binary number 0 (0000 0000) results.",
"If the lowest frequencies occur, the binary number 1 (0000 0001) results.",
"If the next highest frequency occurs the binary number 2 (0000 0010) results.",
"If both the lowest and next highest occur a 3 results.",
"If all frequencies occur the binary number 255 (1111 1111) results.",
"The binary number is the marker which is combined with the video.",
"It is important to note that by associating the marker with the video signal in the fashion of including it in the active video portion of the signal that the marker will not be lost when all of the sync and blanking (or line, field and other ancillary signals if in digital form) are removed from the video signal such as is done as part of the MPEG encoding process.",
"The association of the marker directly with the image carried by the video signal essentially guarantees that no matter what processing, stripping or modification of ancillary portions of the video signal occurs, in either analog or digital form, or conversion of scanning rates, or adjustment of usual video parameters such as black, brightness and chroma, that the marker will still be detectable at the receive location.",
"The transmission channel 8 is utilized in the present example to represent any common or independent use or processing of the video signal 1 and audio signal 2 which may cause or result in unequal delays which lead to timing difficulties.",
"Examples of such uses include transmission, storage and further processing, and in particular include storage and/or transmitting of MPEG encoded audio and video signals.",
"Also it may be noted that marker generators 3 and 13 may respond to video in other forms, or from other parts of the system, or may respond to other signals, for example a genlock reference, in order to achieve proper operation and timing of the marker generator.",
"It may be noted that the use of the video encoder 5 , audio encoder 6 and video and audio combiner 7 is given by way of example, as is usual for MPEG compression and transmission systems which are commonly used in today's television systems.",
"The invention is not limited to the use of such elements however and one of ordinary skill in the art will know how to practice the generation of the marker and the associating of the marker with the video signal in other systems from the present teachings.",
"The combined marker and video signal from 4 and the audio signal 2 may very well be utilized in practicing the present invention without the added elements 5 - 7 .",
"It will be understood that in the present example the elements 9 , 10 and 11 are the receiving side elements complimentary to corresponding transmitting side elements 7 , 5 and 6 respectively.",
"As with 5 , 6 and 7 , elements 9 , 10 and 11 are not required to practice the invention.",
"In particular, video from 4 may be coupled, via a transmission channel directly to element 12 and become video signal 16 .",
"Similarly, audio signal 2 may be coupled via the same or different transmission channel directly to 13 and become audio signal 17 .",
"In the situation where the transmission channel includes storage of the audio and video signals, and storage and recovery is not performed simultaneously, it is noted that a single marker generator 3 may perform the function of 3 upon the storing of the signals and subsequently perform the function of 13 upon the recovery of the stored signals.",
"Other sharing of circuitry between storing and recovery functions may also be had given the assumption that both are not performed simultaneously.",
"FIG. 2 shows the preferred form of the marker generator 3 and 13 of the preferred embodiment of the invention as used with television audio signals.",
"Audio signal 20 which may correspond to 2 or the output of 11 in FIG. 1 is coupled to a bank of 8 bandpass filters 21 a - h which are configured to pass only audio within a range of frequencies as is well known in the art.",
"The output of each bandpass filter is coupled to a comparator 22 a - h respectively.",
"The comparators include hysteresis or other threshold(s) and bipolar response characteristic so that if the positive or negative half cycle of bandpassed audio out of the bandpass filter exceeds a threshold amount set by the hysteresis, the output of the comparator is activated.",
"Each comparator output is respectively coupled to a timing duration circuit 23 a - h .",
"Each timing duration circuit also receives a reset signal from the timing circuit 26 .",
"The timing circuit 26 provides signals to the parallel to serial converter 24 in addition to the reset signal provided to the timing duration circuits 23 .",
"Once the timing duration circuit is reset, it inspects the output signal from its respective comparator 22 .",
"If the output signal from 22 is activated for an established time duration indicating the presence of audio frequencies within the corresponding bandpass filter range, the timing duration circuit sets its output active and holds it active until the next reset signal.",
"The outputs of all of the timing duration circuits 23 are simultaneously latched into the parallel to serial circuit 24 upon command from the timing circuit 26 and shortly thereafter the reset signal to 23 is generated.",
"Also shortly after latching, the bits latched into 24 are caused to be output in serial fashion as marker 25 .",
"The net effect of the circuitry is to set a bit of the timing signal active corresponding to each of the bandpass audio frequencies which was present during the time period from one reset signal to the next, which corresponds to the time period from the generation of one marker to the next.",
"The timing circuit 26 is responsive to the video signal to set the desired time period between markers, as well as to time the output of the marker 25 so that it is associated with the video signal at the correct time.",
"This action will ensure that the marker is placed at the desired position in the video signal.",
"The bandpass filters are preferred to be selected to provide frequent outputs with the expected types of audio signals.",
"For commercial television audio signals it has been found that bandpass filters with center frequencies of 25, 50, 150, 400, 1000, 2500, 6000, 15000 Hz and skirts of 6 dB per octave work well.",
"Other center frequencies and bandwidths may be chosen, and the number of filters changed, to facilitate expected audio signal frequency content.",
"Ideally the frequencies would be chosen such that the lowest frequency filter has an output which is active or makes a change of state only once per period of the maximum expected delay differential of the audio and video signal.",
"Alternatively, other audio characteristics may be relied on in the place of, or in addition to, the detection of energy at particular frequencies as described in respect to the preferred embodiment.",
"Examples include, but are not limited to, impulse characteristics, amplitude characteristics, relationships between different frequency energies, relationships among and between different audio channels.",
"Another example of alternate audio characteristics which may be utilized for the marker is the particular audio sonic characteristics which are relied on for the audio compression.",
"Because these characteristics are already detected in the compression circuitry the present invention may share circuitry thus resulting in lowered cost.",
"Other sharing of circuitry with other functions may be possible depending on the particular signals and environment with which the invention is used.",
"While it has been described to utilize the marker generator with one audio signal in the preferred embodiment, it will be understood that multiple audio signals may be accommodated, with each having a corresponding marker which is associated with the video.",
"Alternatively a plurality of audio signals may be used to generate a lesser number or even one marker by various techniques which include combining the plurality of audio signals before coupling to the marker generator, or by combining various markers each responsive to one or a small number of audio signals with the various markers being combined into a smaller number or a single master marker.",
"It may be noted that many audio ICs which are used for audio graphic equalizer functions contain bandpass filters which may be adapted to use in this invention.",
"Of course it is possible to implement the various elements of the marker generator, as well as the rest of the invention, in analog or digital hardware, or software/hardware or combinations thereof.",
"It will be noted that the present description of the preferred embodiment of the invention is given by way of example.",
"In particular the diagrams of the preferred embodiment are presented as block diagrams and do not show in detail circuitry and cooperation which would be known to those of ordinary skill in the art from the teachings herein without undue experimentation.",
"By way of example it is noted that where one signal line is shown in the block diagram that multiple signals may in actuality be coupled between one block and another, and although separate functional blocks are shown it will be known to make different combinations, arrangements and implementations in order to share elements therebetween and reduce costs.",
"It is also noted that various terms used in the specification, including generator, combiner, encoder, separator, decoder and comparison, and their various tenses are intended to have broader meaning than that ordinarily ascribed thereto with respect to circuit elements, and are intended to cover not only the commonly understood element but the equivalent operation or function as implemented by other circuitry or software/hardware combinations.",
"One of ordinary skill in the art will know to resort to various changes and modifications to the invention as described as well the combination of the invention with other features functions and/or inventive concepts in order to accommodate the use of the invention with particular forms of signals and otherwise to practice the invention in a fashion which is optimized for particular application without departing from the spirit and scope of the invention as hereafter claimed."
] |
This is a divisional patent application of U.S. Ser. No. 098,394, filed Sept. 18, 1987, now U.S. Pat. No. 4,809,030.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a camera designed to be capable of automatically accomplishing flash photography in the daylight.
2. Related Background Art
There has heretofore been known a technique of photometering steady light by a collective photometering system such as center priority photometry when determining the exposure, and as an improvement therein, there has also been put into practical use a technique of uniformly adding a predetermined value (e.g. 1EV) to the exposure value simply calculated from the photometered value.
However, in the former of such prior techniques, there has been a problem that if the portion occupied in the picture plane by a main object to be photographed (a figure or the like) is great, the background of the main object to be photographed becomes over-exposed, and in the latter, improvements are effected in this regard, but where the main object to be photographed does not lie near the central portion of the picture plane, there has been a problem that the background of the main object to be photographed becomes under-exposed.
These problems are attributable to the fact that since the object field is collectively photo-metered, the object field cannot be classified.
Further, with regard also to the control of the amount of flash, in daytime synchro photography, it is controlled by the sum of the steady light and the flash and therefore, classification of the object field is indispensable and accordingly, it has been a fact that satisfactory automatic daytime synchro photography could not be accomplished.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a camera designed such that in flash photography in the daylight, proper steady light exposure and flash can always be automatically obtained in various scenes.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a single lens reflex camera according to first embodiment of the present invention.
FIG. 2 shows the divided state of the object field according to the first embodiment of the present invention.
FIG. 3A and 3B are block diagrams showing the first embodiment of the present invention.
FIG. 4 shows a variation in the method of calculating the exposure value in the first embodiment of the present invention.
FIG. 5 shows a variation in the controlled state of flash photography.
FIG. 6 shows the state of a part of a light beam in the division of the object field according to the first embodiment of the present invention.
FIG. 7 shows the divided state of the picture plane in the vertical position of the camera according to the first embodiment of the present invention.
FIG. 8 shows the divided state of the object field in a modification of the present invention.
FIG. 9 shows a variation in the method of calculating the exposure value in the modification of the present invention.
FIG. 10 shows a variation in the controlled state of flash photography in the modification of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIG. 1, invention may be embodied in a single lens reflex camera.
When a photographing operation is not being performed, a light beam (in this case, a steady light) passed through a photo-taking lens structure 2 is reflected by the mirror 4, indicated by solid lines, of a single lens reflex camera body 1 and passes through a focusing screen 5 and a pentaprism 6, and a part of the light beam is directed to an eyepiece 7 and another part of the light beam is directed to light measuring means 19 having a condensing lens 8 and a light-receiving element 9. The light measuring means 19 has its picture plane (the object field) divided into four areas L, C, R and U as shown in FIG. 2, and is designed to measure the light in the three areas except the area U.
During the photographing operation of the camera, the mirror 4 is moved to a position indicated by broken lines, and both the light emitted from a flash device 3 and reflected and returned by an object to be photographed and the steady light pass through the phototaking lens structure 2 and arrive at a film surface 11 because the mirror 4 is retracted. This light is then reflected by the film surface 11 and directed to light measuring means for a photographing operation which comprises a condensing lens 12 and a light-receiving element 13.
FIG. 3A is a block diagram showing the construction of a camera of the present invention. The light measuring means 19 cooperates with the light-receiving element 9 to logarithmically compress the three output currents I L , I C and I R (the suffixes correspond to the divided three areas L, C and R, respectively) and output them to the converting means 20 of a microcomputer 100. The converting means 20, as shown in U.S. Pat. No. 4,636,054, corrects the outputs of the element 9 corresponding to the currents I L , I C and I R in accordance with the open F-value of the phototaking lens 2 and converts them into luminance values B L , B C and B R .
The microcomputer 100 further has producing means 21 for producing the mean luminance value Ave and the maximum luminance difference Δ which are the luminance information of the object field represented by equations (1) and (2) below, exposure operation means 22 for calculating the exposure value to be described, and selecting means 23 for selecting one level from among a plurality of comparative levels stored in memory means 24. MAX (B L , B C , B R ) indicate the maximum values of B L , B C , B R and MIN (B L , B C , B R ) indicate the minimum values of B L , B C , B R . ##EQU1##
Δ=MAX(B.sub.L,B.sub.C,B.sub.R)-MIN(B.sub.L,B.sub.C,B.sub.R). . . (2)
The exposure operation means 22 is means for subjecting the luminance values B L , B C and B R to high luminance limit processing which will later be described, converting them into B L (*), B C (*) and B R (*) and determining the exposure value therefrom, and has an exposure controlling device connected thereto. The exposure value refers to an amount determined from a combination of the aperture value controlled during photography and the speed value of the shutter. The high luminance limit processing is the processing for keeping the luminance values B L , B C and B R within a predetermined range and accordingly, when the luminance values exceed the predetermined range, the luminance values are converted into the maximum value of the predetermined range.
The selecting means 23 reads out data conforming to Δ and Ave from the memory means 24, and the read-out data is output to a flash controlling device 26. The flash controlling device 26 has the light-receiving element 13, and integrates the output of the light-receiving element 13 and compares the integrated value (the exposure amount) with a comparative level.
The output of the light-receiving element 13 is the sum of the steady light and the flash, and the comparative level is set up to determine the stopping of the flash.
FIG. 3B shows the construction of the flash controlling device 26. An integrating circuit 26a integrates the output of a light-receiving element 13 and outputs the integrated value to a comparing circuit 26b. The comparing circuit 26b compares the comparative level selected by the selecting means 23 with the output of the integrating circuit 26b, and outputs a signal to a controlling circuit 26c when the two are coincident with each other. The controlling circuit 26c is responsive to the signal of the comparing circuit 26b to stop the flashing operation of a flash device 27. The controlling circuit 26c also controls the start of the flash emission of the flash device 27.
FIGS. 4 and 5 show graphs for determining the exposure value and the comparative level, respectively, with the mean luminance value Ave and the value of the maximum luminance difference Δ as parameters and these graphs have been empirically obtained.
First, FIG. 4 is a graph for the calculation of the exposure value, and it is divided into three zones N, BHM(*) and BM(*).
A 1 and A 2 and boundary lines n and m in this graph will now be described. Table 1 below shows the ranges of the values of A 1 , A 2 and k.
TABLE 1______________________________________A.sub.1 (EV) A.sub.2 (EV) k______________________________________10 ± 1 141/2 ± 1 1.sub.-0.5.sup. +1______________________________________
That is, A 1 is of a value of the order of ±1 with 10(EV) as the reference, and A 2 is of a value of the order of ±1 with 141/2(EV) as the reference.
Also, the boundary line n is indicated by Ave=A 1 , and the boundary line m is indicated by Δ=-k(Ave-A 2 ). The constant k assumes a value of the order of +1 or -0.5 with 1 as the reference.
The zone N is a zone in which the mean luminance value Ave is less than a predetermined value A 1 (of the order of 9-10EV(ASA/ISO 100)), and this zone is outside the subject of automatic daylight synchro photography and is the ordinary flash photography area in the nighttime or in dark places such as indoor locations and accordingly, the aperture value and the shutter speed value assume predetermined values, respectively. The zone BM(*) shows the right-hand area with respect to the boundary line m as viewed in FIG. 4, and when this zone is selected, the exposure value is the mean value after the high luminance limit processing, ##EQU2##
Also, the zone BHM(*) shows the area between the boundary lines n and m, and when this zone is selected, the exposure value is the average value of the maximum luminance value BH(*) and the mean value BM(*) after the high luminance limit processing, ##EQU3##
FIG. 5 is a graph for determining the comparative level, and this graph is divided into five zones X0, X2, X22/3, X31/3 and X4. For the determination of the comparative level, the selecting means 23 reads out data corresponding to the comparative level from the memory means 24 in accordance with the address in the memory means 24 determined by the value of Ave of the value of Δ.
A 3 -A 5 and Δ1-Δ4 in this graph will be shown below.
TABLE 2______________________________________A.sub.3 (EV) A.sub.4 (EV) A.sub.5 (EV)______________________________________about 12 about 14 about 142/3______________________________________
TABLE 3______________________________________Δ1 Δ2 Δ3 Δ4______________________________________about 1 about 2 about 21/2 about 3______________________________________
The zone X0, as in FIG. 4 is not the subject area of daylight synchro photography, but is the ordinary flash photography area in the nighttime or in dark places such as indoor locations. The comparative level in this zone is X0, and it is called the standard comparative level.
Assuming that the comparative levels of the zones X2, X22/3, X31/3 and X4 are expressed as X2, X22/3, X31/3 and X4, respectively, the suffixes represents the amounts of shift (EV) in the negative direction from the standard comparative level X0.
For example, assuming that X0 =0.1 [l x ·s ], X22/3 is
X22/3=X0·2.sup.22/3 =0.016[l.sub.x·s].
The values of An and Δn in FIGS. 4 and 5 are somewhat varied by the performance or the like of the light measuring optical system.
In the light measuring means 19, the output currents I L , I C and I R from the light-receiving element 9 are logarithmically compressed and output to the converting means 20. The converting means 20 effects a correction conforming to the open F-value of the photo-taking lens 1 and converts said output currents into luminance values B L , B C and B R , which are output to the producing means 21 and the exposure operation means 22.
The exposure operation means 22 judges whether the luminance values B L , B C and B R are greater than a predetermined luminance value (e.g. 152/3EV(ASA/ISO 100)), and if the luminance values are greater than the predetermined luminance value, it substitutes the predetermined luminance value for said luminance values, and if the luminance values are less than the predetermined luminance value, it leaves said luminance values as they are. That is, the exposure operation means 22 effects the aforementioned high luminance limit processing. The respective luminance values after the high luminance limit processing are defined as B L (*), B C (*) and B R (*).
The mean luminance value Ave of the luminance values B L , B C and B R and the maximum luminance difference Δ are calculated in the producing means, and an appropriate zone is selected by the selecting means 23.
This will be described more specifically.
Let it be assumed that when the camera has been turned on a certain scene, the luminance values measured by the light measuring means 19 are B L =16EV (hereinafter ASA/ISO 100 for all), B C =14EV and B R =151/3EV.
From these luminance values, the mean luminance value Ave and the maximum luminance difference Δ may be found as follows: ##EQU4##
Δ=16-14=2[EV]
Assuming that in FIG. 5, these values Ave=151/9 and Δ=2 correspond to point C, the exposure value and the predetermined exposure amount are selected to the zone BM(*) and the zone 22/3, respectively.
Assuming that the limit value of the high luminance limit processing is 152/3, B L =152/3EV, B C =14EV and B R =151/3EV and therefore, the exposure value is ##EQU5## The exposure operation means 22 sets, for example, as the exposure value, the aperture value to 16 and the shutter speed to 1/125[S](it is to be understood that this is within the speed light tuning speed), and outputs these to the exposure controlling device 25.
Also, by the selecting means 23, a value corresponding to the zone X2 determined by Ave=151/9 and Δ=2, i.e.,
X2=x.sub.0 ·2.sup.<2 =0.025[l.sub.x·s ],
is read out from the memory means 24.
When in this state, release is then effected, exposure is accomplished at an aperture value of 16 and a shutter speed of 1/125[S], and light emission is started by the flash device 27 with the shutter fully opened. The light emission is stopped at a point of time whereat the output of the light-receiving element 13 (the sum of the steady light and the flash) has reached a value integrated by the integrating circuit 26a, i.e., 0.025[l x ·s ]. Photographing is completed at a point of time whereat the shutter has been closed.
In flash photography in the daylight, it is necessary that the exposure determined by the shutter speed and the aperture value be adjusted to the background of the main object to be photographed. Accordingly, in the case of flash photography in the daylight, a good result will generally be obtained at high probability if exposure operation is performed by the average light measurement (in the present embodiment, BM(*)).
However, the tendency for the background to become over-exposed appears in the direction in which the mean luminance value Ave and the maximum luminance difference become smaller and therefore, in the present embodiment, an exposure operation (BHM(*)) in which importance is attached to a high luminance value is effected in this area.
In the present embodiment, the picture plane is divided into the four areas L, C, R and U as shown in FIG. 2, whereas the number of divisions is not limited to four.
Furthermore, description has been given with a TTL flash control type single lens reflex camera taken as an example, but this is not restrictive. The present invention is also applicable, for example, to a lens shutter camera or the like in which light measurement is effected with the object field divided in the open air type.
Description will now be given of the division of the object field of FIG. 2 according to the first embodiment of the present invention.
Here, it is shown that the camera is in the standard supported state. Taking as an example a single lens reflex camera now commercially available, this means that the pentaprism lies above, that is, the camera is leveled in its horizontal position. The element surfaces of the light-receiving element 9 divided into three areas correspond to three areas except the sky side area U.
Also, the central area of the central portion in the four-division shape is of a mean shape between a circular shape and a heart-like shape, as shown. This is particularly effective in a case where the photographer selectively effects the light measurement of the central portion for a special composition, and the detailed shape thereof has been obtained by a simulation and an actual photographing experiment.
FIG. 6 depicts, by hatching, a light beam, of the light beams passed through the focusing screen 5, which passes through the pentaprism 6 and the condensing lens 8 to the light-receiving element 9. The pentaprism 6 is shown developed for each reflecting surface.
As is clear from FIG. 6, where use is made of a pentaprism of such a shape as that of the present embodiment, the upper limit position through which a light beam can pass corresponds to the position of the portion 6a of the pentaprism 6.
Accordingly, by bringing down the portion 6a of the pentaprism 6 as viewed in FIG. 6, it is possible to form a portion which is not photometered by the focal plane of the focusing screen 5, namely, the sky side area U.
Dividing the object field into four areas in the standard supported state so as to photometer the three areas except the sky side area results in the following effects:
(1) Where the camera is brought into the standard supported state (the horizontal position):
Generally, the case where the main portion of the main object to be photographed lies in the sky side area U is nearly nil, and rather it is very often the case that the factors which make exposure improper, such as the sky and the sun, lie in the sky side area U. Accordingly, even if the sky side area U is normally cut so that light measurement is divisionally effected in the other three areas to thereby determine exposure, proper exposure will be obtained at very high probability.
(2) Where the camera is rotated by 1/4 turn about the optic axis of the photo-taking lens relative to the standard supported position(that is, brought into the vertical position) (FIG. 7):
FIG. 7 represents the divided state of the picture plane when the pentaprism has been turned on the left side, and in such case, the right-hand area R lies on the sky side.
Accordingly, where the factors which make exposure improper, such as the sky and the sun, lie in the right-hand area R (generally, such factors often exhibit outstandingly high luminance values as compared with the other areas), this information is deleted or substituted for by another value in the operation stage of the exposure value, whereby proper exposure can be obtained at very high probability.
This also holds true where the direction of the pentaprism is turned on the right side which is opposite to FIG. 7. The portion which is not photometered, i.e., the sky side area U, lies not only on the sky side but also on the ground side, but it has been ascertained by an experiment that this hardly affects the determination of the exposure value because the ratio of the area to the whole is small and the position is near the left or right outer edge.
Thus, by the above-described construction, the factors which make exposure improper, such as the sky and the sun which are liable to lie on the sky side of the object field can be distinguished from the main object to be photographed at high probability and as a result, proper exposure can be obtained at very high probability.
Although in the first embodiment of the present invention, the area U of the divided object field is not photometered, the case as shown in the aforementioned U.S. Pat. No. 4,636,054 wherein a plurality of areas of the divided object field are all photometered is also applied to the camera shown in FIGS. 3A and 3B. Also, in the present embodiment, the object field is divided into a plurality of areas and photometered, but the design may be such that the luminance of the entire object field is measured and the comparative level is selected only by the magnitude of the value of that luminance.
FIG. 8 shows a modification when the object field is divisionally photometered, and FIGS. 9 and 10 depict the graphs for determining the exposure value and the comparative level with the mean luminance value Ave and the value of the maximum luminance difference Δ in the modification of FIG. 8 as parameters, and these graphs have been empirically obtained. H 1 indicates the maximum luminance in the five areas L1, L2, R1, R2 and C shown in FIG. 8, and H 2 indicates the second luminance in the five areas L1, L2, R1, R2 and C. FIG. 8, like FIG. 2, is in the standard supported state.
Values of parameters in FIGS. 9 and 10 are given in the following tables.
TABLE 4______________________________________B.sub.1 B.sub.2 R.sup.3 K.sub.2______________________________________about 101/2 about 131/3 about 151/2 about 8/5______________________________________
TABLE 5______________________________________B.sub.4 B.sub.5 B.sub.6______________________________________about 121/2 about 131/2 about 141/2______________________________________
TABLE 6______________________________________Δ.sub.1 Δ.sub.2 Δ.sub.3______________________________________about 11/2 about 31/3 about 4______________________________________ | A camera includes producing means for detecting the state of the luminance of the object field and producing a luminance information signal conforming to the detected state of the luminance of the object field, control means for calculating the exposure value for exposure of a film on the basis of the luminance information signal and performing the exposing operation of the film, setting means for setting a comparative level on the basis of the luminance information signal, flash emitting means for emitting flash toward the object field in response to the start of the exposing operation by the control means, means for calculating the integrated value of at least a part of the light from the object field at any time in response to the start of the exposing operation by the control means, and stop means for detecting that the integrated value and the comparative level have assumed a predetermined relation and stopping the flash emitting operation of the flash emitting means. | Summarize the key points of the given document. | [
"This is a divisional patent application of U.S. Ser.",
"No. 098,394, filed Sept.",
"18, 1987, now U.S. Pat. No. 4,809,030.",
"BACKGROUND OF THE INVENTION 1.",
"Field of the Invention The present invention relates to a camera designed to be capable of automatically accomplishing flash photography in the daylight.",
"Related Background Art There has heretofore been known a technique of photometering steady light by a collective photometering system such as center priority photometry when determining the exposure, and as an improvement therein, there has also been put into practical use a technique of uniformly adding a predetermined value (e.g. 1EV) to the exposure value simply calculated from the photometered value.",
"However, in the former of such prior techniques, there has been a problem that if the portion occupied in the picture plane by a main object to be photographed (a figure or the like) is great, the background of the main object to be photographed becomes over-exposed, and in the latter, improvements are effected in this regard, but where the main object to be photographed does not lie near the central portion of the picture plane, there has been a problem that the background of the main object to be photographed becomes under-exposed.",
"These problems are attributable to the fact that since the object field is collectively photo-metered, the object field cannot be classified.",
"Further, with regard also to the control of the amount of flash, in daytime synchro photography, it is controlled by the sum of the steady light and the flash and therefore, classification of the object field is indispensable and accordingly, it has been a fact that satisfactory automatic daytime synchro photography could not be accomplished.",
"SUMMARY OF THE INVENTION It is an object of the present invention to provide a camera designed such that in flash photography in the daylight, proper steady light exposure and flash can always be automatically obtained in various scenes.",
"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a single lens reflex camera according to first embodiment of the present invention.",
"FIG. 2 shows the divided state of the object field according to the first embodiment of the present invention.",
"FIG. 3A and 3B are block diagrams showing the first embodiment of the present invention.",
"FIG. 4 shows a variation in the method of calculating the exposure value in the first embodiment of the present invention.",
"FIG. 5 shows a variation in the controlled state of flash photography.",
"FIG. 6 shows the state of a part of a light beam in the division of the object field according to the first embodiment of the present invention.",
"FIG. 7 shows the divided state of the picture plane in the vertical position of the camera according to the first embodiment of the present invention.",
"FIG. 8 shows the divided state of the object field in a modification of the present invention.",
"FIG. 9 shows a variation in the method of calculating the exposure value in the modification of the present invention.",
"FIG. 10 shows a variation in the controlled state of flash photography in the modification of the present invention.",
"DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, invention may be embodied in a single lens reflex camera.",
"When a photographing operation is not being performed, a light beam (in this case, a steady light) passed through a photo-taking lens structure 2 is reflected by the mirror 4, indicated by solid lines, of a single lens reflex camera body 1 and passes through a focusing screen 5 and a pentaprism 6, and a part of the light beam is directed to an eyepiece 7 and another part of the light beam is directed to light measuring means 19 having a condensing lens 8 and a light-receiving element 9.",
"The light measuring means 19 has its picture plane (the object field) divided into four areas L, C, R and U as shown in FIG. 2, and is designed to measure the light in the three areas except the area U. During the photographing operation of the camera, the mirror 4 is moved to a position indicated by broken lines, and both the light emitted from a flash device 3 and reflected and returned by an object to be photographed and the steady light pass through the phototaking lens structure 2 and arrive at a film surface 11 because the mirror 4 is retracted.",
"This light is then reflected by the film surface 11 and directed to light measuring means for a photographing operation which comprises a condensing lens 12 and a light-receiving element 13.",
"FIG. 3A is a block diagram showing the construction of a camera of the present invention.",
"The light measuring means 19 cooperates with the light-receiving element 9 to logarithmically compress the three output currents I L , I C and I R (the suffixes correspond to the divided three areas L, C and R, respectively) and output them to the converting means 20 of a microcomputer 100.",
"The converting means 20, as shown in U.S. Pat. No. 4,636,054, corrects the outputs of the element 9 corresponding to the currents I L , I C and I R in accordance with the open F-value of the phototaking lens 2 and converts them into luminance values B L , B C and B R .",
"The microcomputer 100 further has producing means 21 for producing the mean luminance value Ave and the maximum luminance difference Δ which are the luminance information of the object field represented by equations (1) and (2) below, exposure operation means 22 for calculating the exposure value to be described, and selecting means 23 for selecting one level from among a plurality of comparative levels stored in memory means 24.",
"MAX (B L , B C , B R ) indicate the maximum values of B L , B C , B R and MIN (B L , B C , B R ) indicate the minimum values of B L , B C , B R .",
"##EQU1## Δ=MAX(B.",
"sub.",
"L,B.",
"sub.",
"C,B.",
"sub.",
"R)-MIN(B.",
"sub.",
"L,B.",
"sub.",
"C,B.",
"sub.",
"R).",
"(2) The exposure operation means 22 is means for subjecting the luminance values B L , B C and B R to high luminance limit processing which will later be described, converting them into B L (*), B C (*) and B R (*) and determining the exposure value therefrom, and has an exposure controlling device connected thereto.",
"The exposure value refers to an amount determined from a combination of the aperture value controlled during photography and the speed value of the shutter.",
"The high luminance limit processing is the processing for keeping the luminance values B L , B C and B R within a predetermined range and accordingly, when the luminance values exceed the predetermined range, the luminance values are converted into the maximum value of the predetermined range.",
"The selecting means 23 reads out data conforming to Δ and Ave from the memory means 24, and the read-out data is output to a flash controlling device 26.",
"The flash controlling device 26 has the light-receiving element 13, and integrates the output of the light-receiving element 13 and compares the integrated value (the exposure amount) with a comparative level.",
"The output of the light-receiving element 13 is the sum of the steady light and the flash, and the comparative level is set up to determine the stopping of the flash.",
"FIG. 3B shows the construction of the flash controlling device 26.",
"An integrating circuit 26a integrates the output of a light-receiving element 13 and outputs the integrated value to a comparing circuit 26b.",
"The comparing circuit 26b compares the comparative level selected by the selecting means 23 with the output of the integrating circuit 26b, and outputs a signal to a controlling circuit 26c when the two are coincident with each other.",
"The controlling circuit 26c is responsive to the signal of the comparing circuit 26b to stop the flashing operation of a flash device 27.",
"The controlling circuit 26c also controls the start of the flash emission of the flash device 27.",
"FIGS. 4 and 5 show graphs for determining the exposure value and the comparative level, respectively, with the mean luminance value Ave and the value of the maximum luminance difference Δ as parameters and these graphs have been empirically obtained.",
"First, FIG. 4 is a graph for the calculation of the exposure value, and it is divided into three zones N, BHM(*) and BM(*).",
"A 1 and A 2 and boundary lines n and m in this graph will now be described.",
"Table 1 below shows the ranges of the values of A 1 , A 2 and k. TABLE 1______________________________________A.",
"sub[.",
"].1 (EV) A.sub[.",
"].2 (EV) k______________________________________10 ± 1 141/2 ± 1 1.",
"sub.",
"-0.5.",
"sup.",
"+1______________________________________ That is, A 1 is of a value of the order of ±1 with 10(EV) as the reference, and A 2 is of a value of the order of ±1 with 141/2(EV) as the reference.",
"Also, the boundary line n is indicated by Ave=A 1 , and the boundary line m is indicated by Δ=-k(Ave-A 2 ).",
"The constant k assumes a value of the order of +1 or -0.5 with 1 as the reference.",
"The zone N is a zone in which the mean luminance value Ave is less than a predetermined value A 1 (of the order of 9-10EV(ASA/ISO 100)), and this zone is outside the subject of automatic daylight synchro photography and is the ordinary flash photography area in the nighttime or in dark places such as indoor locations and accordingly, the aperture value and the shutter speed value assume predetermined values, respectively.",
"The zone BM(*) shows the right-hand area with respect to the boundary line m as viewed in FIG. 4, and when this zone is selected, the exposure value is the mean value after the high luminance limit processing, ##EQU2## Also, the zone BHM(*) shows the area between the boundary lines n and m, and when this zone is selected, the exposure value is the average value of the maximum luminance value BH(*) and the mean value BM(*) after the high luminance limit processing, ##EQU3## FIG. 5 is a graph for determining the comparative level, and this graph is divided into five zones X0, X2, X22/3, X31/3 and X4.",
"For the determination of the comparative level, the selecting means 23 reads out data corresponding to the comparative level from the memory means 24 in accordance with the address in the memory means 24 determined by the value of Ave of the value of Δ.",
"A 3 -A 5 and Δ1-Δ4 in this graph will be shown below.",
"TABLE 2______________________________________A.",
"sub[.",
"].3 (EV) A.sub[.",
"].4 (EV) A.sub[.",
"].5 (EV)______________________________________about 12 about 14 about 142/3______________________________________ TABLE 3______________________________________Δ1 Δ2 Δ3 Δ4______________________________________about 1 about 2 about 21/2 about 3______________________________________ The zone X0, as in FIG. 4 is not the subject area of daylight synchro photography, but is the ordinary flash photography area in the nighttime or in dark places such as indoor locations.",
"The comparative level in this zone is X0, and it is called the standard comparative level.",
"Assuming that the comparative levels of the zones X2, X22/3, X31/3 and X4 are expressed as X2, X22/3, X31/3 and X4, respectively, the suffixes represents the amounts of shift (EV) in the negative direction from the standard comparative level X0.",
"For example, assuming that X0 =0.1 [l x ·s ], X22/3 is X22/3=X0·2.",
"sup[.",
"].22/3 =0.016[l.",
"sub.",
"x·s].",
"The values of An and Δn in FIGS. 4 and 5 are somewhat varied by the performance or the like of the light measuring optical system.",
"In the light measuring means 19, the output currents I L , I C and I R from the light-receiving element 9 are logarithmically compressed and output to the converting means 20.",
"The converting means 20 effects a correction conforming to the open F-value of the photo-taking lens 1 and converts said output currents into luminance values B L , B C and B R , which are output to the producing means 21 and the exposure operation means 22.",
"The exposure operation means 22 judges whether the luminance values B L , B C and B R are greater than a predetermined luminance value (e.g. 152/3EV(ASA/ISO 100)), and if the luminance values are greater than the predetermined luminance value, it substitutes the predetermined luminance value for said luminance values, and if the luminance values are less than the predetermined luminance value, it leaves said luminance values as they are.",
"That is, the exposure operation means 22 effects the aforementioned high luminance limit processing.",
"The respective luminance values after the high luminance limit processing are defined as B L (*), B C (*) and B R (*).",
"The mean luminance value Ave of the luminance values B L , B C and B R and the maximum luminance difference Δ are calculated in the producing means, and an appropriate zone is selected by the selecting means 23.",
"This will be described more specifically.",
"Let it be assumed that when the camera has been turned on a certain scene, the luminance values measured by the light measuring means 19 are B L =16EV (hereinafter ASA/ISO 100 for all), B C =14EV and B R =151/3EV.",
"From these luminance values, the mean luminance value Ave and the maximum luminance difference Δ may be found as follows: ##EQU4## Δ=16-14=2[EV] Assuming that in FIG. 5, these values Ave=151/9 and Δ=2 correspond to point C, the exposure value and the predetermined exposure amount are selected to the zone BM(*) and the zone 22/3, respectively.",
"Assuming that the limit value of the high luminance limit processing is 152/3, B L =152/3EV, B C =14EV and B R =151/3EV and therefore, the exposure value is ##EQU5## The exposure operation means 22 sets, for example, as the exposure value, the aperture value to 16 and the shutter speed to 1/125[S](it is to be understood that this is within the speed light tuning speed), and outputs these to the exposure controlling device 25.",
"Also, by the selecting means 23, a value corresponding to the zone X2 determined by Ave=151/9 and Δ=2, i.e., X2=x.",
"sub[.",
"].0 ·2.",
"sup.",
"<2 =0.025[l.",
"sub.",
"x·s ], is read out from the memory means 24.",
"When in this state, release is then effected, exposure is accomplished at an aperture value of 16 and a shutter speed of 1/125[S], and light emission is started by the flash device 27 with the shutter fully opened.",
"The light emission is stopped at a point of time whereat the output of the light-receiving element 13 (the sum of the steady light and the flash) has reached a value integrated by the integrating circuit 26a, i.e., 0.025[l x ·s ].",
"Photographing is completed at a point of time whereat the shutter has been closed.",
"In flash photography in the daylight, it is necessary that the exposure determined by the shutter speed and the aperture value be adjusted to the background of the main object to be photographed.",
"Accordingly, in the case of flash photography in the daylight, a good result will generally be obtained at high probability if exposure operation is performed by the average light measurement (in the present embodiment, BM(*)).",
"However, the tendency for the background to become over-exposed appears in the direction in which the mean luminance value Ave and the maximum luminance difference become smaller and therefore, in the present embodiment, an exposure operation (BHM(*)) in which importance is attached to a high luminance value is effected in this area.",
"In the present embodiment, the picture plane is divided into the four areas L, C, R and U as shown in FIG. 2, whereas the number of divisions is not limited to four.",
"Furthermore, description has been given with a TTL flash control type single lens reflex camera taken as an example, but this is not restrictive.",
"The present invention is also applicable, for example, to a lens shutter camera or the like in which light measurement is effected with the object field divided in the open air type.",
"Description will now be given of the division of the object field of FIG. 2 according to the first embodiment of the present invention.",
"Here, it is shown that the camera is in the standard supported state.",
"Taking as an example a single lens reflex camera now commercially available, this means that the pentaprism lies above, that is, the camera is leveled in its horizontal position.",
"The element surfaces of the light-receiving element 9 divided into three areas correspond to three areas except the sky side area U. Also, the central area of the central portion in the four-division shape is of a mean shape between a circular shape and a heart-like shape, as shown.",
"This is particularly effective in a case where the photographer selectively effects the light measurement of the central portion for a special composition, and the detailed shape thereof has been obtained by a simulation and an actual photographing experiment.",
"FIG. 6 depicts, by hatching, a light beam, of the light beams passed through the focusing screen 5, which passes through the pentaprism 6 and the condensing lens 8 to the light-receiving element 9.",
"The pentaprism 6 is shown developed for each reflecting surface.",
"As is clear from FIG. 6, where use is made of a pentaprism of such a shape as that of the present embodiment, the upper limit position through which a light beam can pass corresponds to the position of the portion 6a of the pentaprism 6.",
"Accordingly, by bringing down the portion 6a of the pentaprism 6 as viewed in FIG. 6, it is possible to form a portion which is not photometered by the focal plane of the focusing screen 5, namely, the sky side area U. Dividing the object field into four areas in the standard supported state so as to photometer the three areas except the sky side area results in the following effects: (1) Where the camera is brought into the standard supported state (the horizontal position): Generally, the case where the main portion of the main object to be photographed lies in the sky side area U is nearly nil, and rather it is very often the case that the factors which make exposure improper, such as the sky and the sun, lie in the sky side area U. Accordingly, even if the sky side area U is normally cut so that light measurement is divisionally effected in the other three areas to thereby determine exposure, proper exposure will be obtained at very high probability.",
"(2) Where the camera is rotated by 1/4 turn about the optic axis of the photo-taking lens relative to the standard supported position(that is, brought into the vertical position) (FIG.",
"7): FIG. 7 represents the divided state of the picture plane when the pentaprism has been turned on the left side, and in such case, the right-hand area R lies on the sky side.",
"Accordingly, where the factors which make exposure improper, such as the sky and the sun, lie in the right-hand area R (generally, such factors often exhibit outstandingly high luminance values as compared with the other areas), this information is deleted or substituted for by another value in the operation stage of the exposure value, whereby proper exposure can be obtained at very high probability.",
"This also holds true where the direction of the pentaprism is turned on the right side which is opposite to FIG. 7. The portion which is not photometered, i.e., the sky side area U, lies not only on the sky side but also on the ground side, but it has been ascertained by an experiment that this hardly affects the determination of the exposure value because the ratio of the area to the whole is small and the position is near the left or right outer edge.",
"Thus, by the above-described construction, the factors which make exposure improper, such as the sky and the sun which are liable to lie on the sky side of the object field can be distinguished from the main object to be photographed at high probability and as a result, proper exposure can be obtained at very high probability.",
"Although in the first embodiment of the present invention, the area U of the divided object field is not photometered, the case as shown in the aforementioned U.S. Pat. No. 4,636,054 wherein a plurality of areas of the divided object field are all photometered is also applied to the camera shown in FIGS. 3A and 3B.",
"Also, in the present embodiment, the object field is divided into a plurality of areas and photometered, but the design may be such that the luminance of the entire object field is measured and the comparative level is selected only by the magnitude of the value of that luminance.",
"FIG. 8 shows a modification when the object field is divisionally photometered, and FIGS. 9 and 10 depict the graphs for determining the exposure value and the comparative level with the mean luminance value Ave and the value of the maximum luminance difference Δ in the modification of FIG. 8 as parameters, and these graphs have been empirically obtained.",
"H 1 indicates the maximum luminance in the five areas L1, L2, R1, R2 and C shown in FIG. 8, and H 2 indicates the second luminance in the five areas L1, L2, R1, R2 and C. FIG. 8, like FIG. 2, is in the standard supported state.",
"Values of parameters in FIGS. 9 and 10 are given in the following tables.",
"TABLE 4______________________________________B.",
"sub[.",
"].1 B.sub[.",
"].2 R.sup[.",
"].3 K.sub[.",
"].2______________________________________about 101/2 about 131/3 about 151/2 about 8/5______________________________________ TABLE 5______________________________________B.",
"sub[.",
"].4 B.sub[.",
"].5 B.sub[.",
"].6______________________________________about 121/2 about 131/2 about 141/2______________________________________ TABLE 6______________________________________Δ.",
"sub[.",
"].1 Δ.",
"sub[.",
"].2 Δ.",
"sub[.",
"].3______________________________________about 11/2 about 31/3 about 4______________________________________"
] |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] N/A
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] N/A
BACKGROUND OF THE INVENTION
[0003] This invention relates generally to a method of assembling a semiconductor chip electrically and mechanically connected to a substrate, particularly in a flip chip configuration.
[0004] Assembly of solder bumped chips such as flip chip or chip scale package (SCP) is an emerging technology which satisfies the demands of the ever-increasing requirements for high I/O density, small form factor, and improved performance in integrated circuit (IC) design. In the process of chip assembly, a chip is mounted on a substrate with any kind of interconnect material. Among the many kinds of interconnect materials, solder has remained a predominant choice. Solder bumped chip assembly consists two major steps: (1) chip soldering and (2) underfill encapsulation. To attach chip to the substrate, a flux is applied to the substrate or solder bumps on the chip. The chip is then aligned with the bond pads on the substrate, placed, and reflowed, forming electrical connections and mechanical joints between flip chip and substrate. After soldering a solvent cleaning step is usually involved to remove the flux residue which otherwise weakens the underfill adhesion which in turn degrades solder joint reliability. The cleaning process is a difficult operation, often costly and time consuming, involving solvents and expensive equipments. Therefore, there is a need to develop a new technology that does not require this cleaning process.
[0005] Another issue in the implementation of solder bumped chip technology when applied to organic polymer substrate is the mismatch of the coefficient of thermal expansion (CTE) of the chip, and that of the substrate having a higher CTE. The build up stress on solder joints upon thermal excursions experienced during the application of the device causes solder joint fatigue and leads to the failure of the interconnect joints. To minimize this problem, an underfill material is applied in the interspace of chip and substrate after chip soldering to assure the reliability and electric integrity. The traditional underfill material is typically a highly flowable liquid formulation, containing filler particles to reduce CTE. The underfill material is dispensed along the edges of the chip and allowed to wick into the space between the substate and the chip. The capillary action allows the underfill to flow out to the opposite sides of the chip and completely fill the gap between the chip and the substrate. Even though the substrate is usually heated to an elevated temperature to facilitate the underfill flow, the process still takes more than seconds to completely underfill the chip, which is considered a bottle neck in manufacturing process. After underfilling, the package is subjected to an elevated temperature for underfill curing. The cured underfill material redirects or redistributes the stress away from tiny solder joints, thus enhancing the package reliability. In addition, underfill materials also serve as mechanical and environmental protection, which increases the resistance to shock, vibration, moisture, solvent, and provide thermal dissipation between chip and substrate.
[0006] While traditional capillary flow underfill materials with reduced flow and cure time are dominant in current underfill applications, the use of so-called pre-deposit fluxing underfill offers an attractive alternative which would speed up package processing and enhance compatibility with surface mount technology (SMT). In addition to bearing the functions provided by traditional underfill encapsulant, the pre-deposit underfill materials are integrated with fluxing capability. The overall assembly process based on this type of underfill material is simplified by combining three basic steps: (1) underfill dispensing, (2) chip placement, and (3) reflow. During reflow, the fluxing agent incorporated in underfill materials provides sufficient activity to remove surface oxide on solder bumps and bond pads, forming interconnect joints. In the meantime, the underfill material is chemically crosslinked, forming a strong network structure providing mechanical and environmental protection as described for traditional underfill encapsulation. The benefits of the pre-deposit underfill process are well explored in the recent years. These include simpler process to control, higher throughput, self-fluxing action, etc. Even though there has been an explosion of interest and great effort to develop this technology throughout the past decade, the use of pre-deposit underfill is, however, not without its inherent problems and limitations. One of the obstacles which pre-deposited fluxing underfill materials must overcome, is placement of the component without void entrapment. A direct consequence of underfill pre-deposit followed by fast paced chip placement (less then a second), is that the underfill material is forced to flow toward the periphery of the chip in such a short time that air is entrapped around solder bumps (FIG. 2). These air bubbles will generate internal vapor pressure when the temperature increases during reflow, leading to process failures such as chip float and misalignment of solder bumps relative to the matching bond pads. Furthermore, the trapped air bubbles around solder joints pose a great threat to the solder joint performance, defects such as irregularity, solder extrusion, incomplete wetting, voids inside joint are often encountered. Yet, another challenge of developing such pre-deposit fluxing underfill materials is the interference of inorganic filler particles on soldering during reflow as solid filler particles will inhibit the solder wetting on bonding pads. How to incorporate fillers into pre-deposit fluxing underfill to reduce CTE and apply such pre-deposit underfill in manufacture processing remains uncertain. As a result, the pre-deposit underfill typically contains no filler, thus has a CTE much higher than that of capillary flow underfill and therefore unparallel performance.
[0007] It would be desirable to develop a method that takes advantages of capillary flow underfill process, such as void free, low CTE, widely accepted industry processing practice, and combines the attractive features of fluxing underfill such as shorter manufacturing cycle, no cleaning step required, underfill cured in the same step as solder reflow, and SMT processing compatibility. Such a processing method should yield overall higher efficiency, and low cost without compromising the reliability and performance.
BRIEF SUMMARY OF THE INVENTION
[0008] The present invention provides a method of assembling a substrate and an IC die in a flip chip configuration using a tacky thermosettable flux and underfilling such a device. According to the present invention, as described in the illustrated embodiments, a thin layer of tacky flux is applied to the substrate or preferably to the solder bumps, a chip is placed on the substrate with the solder bumps in contact with the matching bonding pads. The tacky flux provides temporary adhesive bonding to immobilize the chip. An underfill is then dispensed along the edges of the chip and the whole package is transferred to reflow process. During solder reflow process, three major processing tasks are accomplished in one single step: (1) the underfill flows into the gap between chip and substrate and completely fills the interspace, (2) the tacky flux activates the bonding surface and facilitates solder reflow and joint formation, (3) underfill curing. Because tacky flux is formulated to be compatible with underfill, it is chemically incorporated into the cured underfill network structure.
[0009] In one aspect of present invention there is provided an integrated method of underfilling a device on a substrate during reflow process. The method comprises applying tacky flux to solder bumps or substrate to be joined and placing the chip on substrate so that the chip is temporarily held in place. The underfill is deposited on the substrate along the edges of the chip and the whole device is subjected to a reflow process. In general, a reflow process can be roughly divided into four major stages: heating stage, soaking stage, and the reflow and cooling stage. The viscosity of underfill material is reduced as the temperature of the whole device is gradually increased in the heating stage, this will facilitate the underfill to flow into the gap, as a result, the gap is completely filled with underfill material before the temperature reaches the solder melting point. Because the underfill is allowed to flow, via capillary action, into the gap between chip and substrate, the underfill material is able to wet any surface in contact and replace the air space underneath the die with underfill material, avoiding the formation of air bubbles. The incorporation of underfilling into the solder reflow process removes the typical bottleneck of the manufacturing process, thus significantly shortening the manufacturing cycle.
[0010] Another aspect of the present invention is increased gap height during the underfilling process. Because the device is underfilled before reflow and solder collapse, the maximum clearance between chip and substrate for the underfill process is increased. The size of the gap is controlled by the height of solder bumps and typically varies from 3 to 30 mils. With the increase of I/O density in IC devices, the solder bumps (i.e., the clearance between the chip and the substrate) are becoming even smaller. This reduced height presents a greater challenge for the underfill, making capillary flow more difficult and increasing the time needed to fill the gap. Typically, depending on the pad design and layout, there is a 15-30% drop in the clearance after solder reflow in C4 (controlled collapse chip connection) process, this clearance drop further increases the chance of introducing underfill defects such as voids, filler segregation, and increased flow time. Underfilling before soldering provides the maximum clearance for the underfilling process.
[0011] In another aspect of present invention, a uniform fillet is formed after solder reflow. Traditional process of chip bonding first followed by underfill dispensing tends to create a non-uniform fillet around the chip. Typically, the fillet will be large enough on the one or two sides of chip where the underfill is originally dispensed and there is not enough underfill material flowing out to the other sides of the chip to form a desirable fillet profile. An additional dispensing operation is usually required to compensate the material deficiency on the other sides, which also brings in additional manufacturing time. Underfilling before solder collapse assures the formation of uniform fillet. Upon solder collapse, the chip will force the additional underfill material to flow out to the edges of the chip, providing enough material to form a desirable fillet.
[0012] In another aspect of present invention, a tacky flux is provided to block the interference of filler particles on the solder joint formation. The current process of pre-deposit fluxing underfill does not allow the use of underfill material with a high percentage of filler to achieve a sufficiently low CTE, usually around 25-45 ppm/° C. Use of high percentage of filler content inhibits solder wetting on bond pads, thus preventing the formation of a desirable solder joint. This is why current formulations of this type of pre-deposit fluxing underfill usually contain no or very low percentages of fillers. The resulted high CTE of the material limits the performance of the final package. The process of the present invention takes advantage of tacky flux to prevent the interference of filler during solder reflow, with the tacky flux forming a thin layer adhering to the contacting bump and pad, and acting as a physical barrier to the filler intrusion. A 100% interconnect yield can be achieved reproducibly.
BRIEF DESCRIPTION OF THE FIGURES
[0013] [0013]FIG. 1 is a process flow chart illustrating the steps for assembling a chip and substrate in accordance with conventional capillary flow underfill process.
[0014] [0014]FIG. 2 is a process flow chart illustrating the steps for assembling a chip and substrate in accordance with pre-deposit fluxing underfill process.
[0015] [0015]FIG. 3 is the comparison of entrapped voids after chip placement on glass substrate using different process: (A) pre-deposit underfill process, (B) pre-deposit underfill process after cure, and (C) the present integrated process. Flip Chip Technology FA10-200 on glass substrate with 5 mil bump diameter and 10 mil pitch is used for this illustration.
[0016] [0016]FIG. 4 is a process flow chart illustrating the steps for assembling a chip and in accordance with present invention-option 1.
[0017] [0017]FIG. 5 is the x-ray images of assembled Flip Chip FB250 with organic surface protection (OSP) coating on pads using the process in accordance with the present invention-option 1. Indium tacky epoxy flux PK-X003 and underfill UF-X10 containing 20% filler (A) and 40% filler (B) is used for this illustration.
[0018] [0018]FIG. 6 is a process flow chart illustrating the steps for assembling a chip and substrate in accordance with present invention-option 2.
[0019] [0019]FIG. 7 shows the integration of underfill, curing and solder bump reflow into one reflow step. The underfilling process can be completed in a reflow oven or before the package is sent into a reflow oven. Also shown is the typical reflow profile described in four stages: (1) heating stage, (2) soaking stage, (3) reflow and (4) cooling stage.
DETAILED DESCRIPTION OF THE INVENTION
[0020] A new integrated void free process for assembling solder bumped chips such as flip chip or chip scale packages (CSP) using a tacky thermosettable flux is provided. The tacky flux is not only sufficiently tacky to keep the chip attached to the substrate while other processing (e.g., addition of the underfill) takes place, but also fully compatible with underfill and will not cause delamination. The traditional tacky fluxes were generally incompatible with underfills and caused delamination of the underfills. They were used with “regular” soldering, processes in which underfills were not used. These traditional products contained much resin (which added the stickiness to the product), along with solvent and activator.
[0021] By tacky thermosettable flux, we mean a flux which is flowable before reflow, provides good flux properties (e.g., removal of oxides, etc.), and, after reflow, is cross-linked to form a thermosetting polymer. Examples of tacky thermosettable flux include epoxy fluxes, polyimide fluxes, polyacrylate fluxes, polyurethane fluxes, and combinations thereof. Other polymers that perform similarly also can be used, either individually or in combination with other such fluxes.
[0022] Furthermore, the area of prime interest herein is the new process that results from use of the new tacky thermosettable flux. As indicated in more detail below, the new process allows the combination of several steps that were previous conducted separately, thus simplifying the underfilling, reflow and curing steps. Furthermore, the resulting IC has a much lower failure rate, due to the absence of underfill voids in the new process. It should be noted that, although several tacky fluxes are disclosed herein, the new process is not confined to the use of those fluxes. Instead, any flux that is sufficiently sticky to hold the chip to the substrate during the steps discussed can be used in the new process. (I.e., the flux must be sufficiently sticky to prevent the component from floating away.)
[0023] The tacky flux is first applied to the solder bumps or substrate using conventional methods followed by placement of the chip onto the substrate so that the solder bumps are in contact with the substrate bond pads. The underfill is then dispensed along the edges of the chip and the device is transferred to a reflow cycle. During the reflow heating, the underfill material flows into the space between chip and substrate, driven by capillary action, leaving no entrapped voids in the underfill. In the meantime, the device is reflowed and cured. The tacky epoxy flux is designed to provide temporary adhesion between the electronic components and substrate as well as provide fluxing activity for soldering during reflow. The tacky flux can be composed of one or more fluxing agents and a combination of epoxy (or other fluxes listed above), hardener, and/or curing agent. The tacky epoxy flux is formulated to have similar chemical nature as epoxy based underfill materials and thereby will be incorporated into the final polymer network structure through diffusion and chemical reaction after reflow, without deterioration of the underfill performance. The tackiness is provided by the high molecular weight epoxy, hardener, or the combination of the two. The new process consolidates underfilling, solder reflow, and underfill curing into a one-step reflow process, thereby simplifying the flip chip packaging process which otherwise requires separate solder reflow and underfilling steps. The new process combines the advantages of conventional void free capillary flow underfill process and simple pre-deposit fluxing underfill process, and therefore optimizes the manufacturing process without compromising any performance requirements. The tacky flux will prevent the chip from floating, which will cause misalignment between bond pad and solder bumps. The sequence of underfilling before solder reflow facilitates underfill flow because of the increased clearance between the chip and substrate created by the unreflowed solder bumps.
[0024] [0024]FIG. 1 illustrates the typical process of assembling a chip and a substrate or chip carrier by conventional capillary flow underfilling. The substrate ( 101 ) typically comprises silicon, ceramic, glass, FR-4, BCB, polyimide, or combination thereof, and is fabricated as printed circuit board (PCB) or chip carrier used in flip-chip technology. The substrate has coplanar metallurgical bond pads ( 102 ). The flux is applied to the substrate as a thin film ( 103 ) using various flux application methods such as spray, brushing, pin transferring and printing. Alternatively, the flux can be applied to the solder bumps attached to the flip chip by dipping the solder bumps into a thin layer of flux on a motorized flux tray (not shown). The bumps can be Pb-based or Pb-free solder alloys. A chip ( 104 ) is shown mounted on a substrate ( 101 ) with solder bumps ( 105 ) connected to the chip aligned with the bond pads ( 102 ) of the substrate ( 101 ). During reflow, the flux ( 103 ) removes the oxide on the surface of solder bumps ( 105 ) attached to the chip ( 104 ) and the oxide on the bond pads ( 102 ) on the substrate ( 101 ), a mechanical and electrical solder joint ( 106 ) is thus formed between chip ( 104 ) and substrate ( 101 ). The chip/substrate combination is cleaned to remove the flux residue ( 107 ) which otherwise, will hinder the underfill flow and degrade the adhesion of underfill to the substrate, chip and solder joints. An underfill material ( 108 ) is dispensed through a needle ( 109 ) and deposited along the edges of bonded chip using predetermined patterns such as one-side, L type pattern, double L pass, or L pass followed by another L pass on the opposite sides. The underfill material ( 108 ) is allowed to wick into the gap formed between bottom side of the chip and the top of the substrate by capillary action. The underfill flow process is usually facilitated by heating the substrate to a temperature T2, which is dependent upon the flux used and is described in more detail later herein. Generally, the temperature is between approximately 20 and 130° C. The flow process can be completed in a matter of seconds depending on chip size, clearance between chip and substrate, I/O density, and the selected underfill material. As the result of capillary flow, the underfill material is able to replace any air in the interspace between chip and substrate. After underfilling, the whole device is subjected to a high temperature curing process which can be varied from few minutes to few hours. A mechanically strong and stable adhesive layer ( 110 ) is formed between chip and substrate, providing stress relief and environmental protection to the package.
[0025] While conventional capillary flow underfills now possess improved flow speed and cure rate, they still require a few more processing steps beyond the typical SMT process which typically consists of solder paste or flux deposition, component placement, and reflow soldering. In recent years, pre-deposit fluxing underfill materials have been extensively explored in order to meet the demand of low cost, high throughput, and SMT compatibility. The overall manufacturing process is simplified significantly as illustrated in FIG. 2. The underfill material ( 201 ) is deposited, in a desired pattern, onto the substrate ( 202 ), which has been baked beforehand to release any surface moisture. A solder bumped chip ( 203 ) is mounted onto the substrate with solder bumps ( 204 ) aligned to the corresponding bond pads of the substrate ( 205 ) in a one-to-one fashion. During the same reflow process as used for reflowing solder paste, the underfill material ( 206 ) provides the fluxing capability to assist the formation of solder joint ( 208 ) and undergoes a curing reaction to form a protective underfill layer ( 209 ). Although extensive effort has been made to promote this technology, many problems still exist as this moves into real world of applications. One of the inherent problems is the void entrapped during chip placement. This is because the underfill material ( 206 ) is unable to fully wet the surface and expel the air out of the space between chip and substrate before fast paced chip placement (typically less than one second) is completed. A confined air bubble ( 207 ) is formed around the corner of each individual solder bump, mostly behind solder bumps along the underfill flow direction. This situation becomes more significant when a fully populated area array solder bumped chip is used as demonstrated in FIG. 3(A). These air bubbles, with diameters about one-third to half the diameter of solder balls, pose a great threat to the integrity of solder joint reliability. Solder joint failure such as solder extrusion, and joint cracking has been reported due to the presence of these voids ( 210 ) in the cured underfill. The situation can be worsened when these air bubbles expand and/or merge to form bigger bubbles (FIG. 3(B)), thus causing a greater chance of chip floating or solder joint failure.
[0026] The present invention provides an integrated solution to the problems associated with the prior art and takes advantages of capillary flow void free underfilling and a simplified manufacturing process. These advantages will be made clear in the following detailed description and accompanying drawings of the present invention.
[0027] Illustrated in FIG. 4 is representative of the processes for assembling a chip in accordance with the present invention. The process begins with the application of tacky epoxy flux ( 403 ) on either substrate ( 407 ) or solder bumps ( 402 ) attached to a chip ( 401 ). There are several methods available for applying tacky flux to a substrate or solder bumps. For examples, brushing, printing, spraying, roller coating, pin transferring, or dispensing are well known techniques used in this field. Another method, often called flux dipping, involves the use of rotary drum having a doctor blade to control the flux thickness. The rotary drum has a temperature controller, providing a proper viscosity, to enable a high volume manufacturing process. These rotary drum flux applicators are readily available from pick and place machine vendors. The tacky epoxy flux has sufficient chemical activity to activate solder bumps to form reliable solder joints with bond pads, sufficient tacky force to adhere the substrate and pre-aligned chip during underfilling, and a proper viscosity to enable high volume manufacturing process. The tacky epoxy flux is typically composed of one or more fluxing agents, and a combination of tacky epoxy, hardener, and/or curing agent. (As indicated above, other types of fluxes, such as polyimide fluxes, can also be utilized.) The tacky flux is formulated with compositions compatible with or similar to underfill composition and therefore will be incorporated into the adhesive network structure after reflow heating cycle. In this context the word compatible means that the tacky fluxs are composed of chemicals which are reactive to the epoxy or other compositions in underfill material. During reflow heating, the tacky flux is solublized in the underfill material and become a part of the net work structure after curing.
[0028] Examples of tacky fluxes include PK-001 and PK-002, products sold by Indium Corporation of America. One example of a tacky epoxy flux that can be applied at an ambient temperature is PK-X003 manufactured by Indium Corporation of America, the room temperature Brookfield viscosity of this material is around 50000 cps. However, it should be emphasized that other tacky fluxes can also be used.
[0029] One example of an underfill that can be used along with this epoxy flux is UF-X10, also manufactured by Indium Corporation of America. The Brookfield viscosity of this underfill is around 3000 cps at room temperature. Note that the underfill can contain additional flux to further improve the efficiency of the reflow process.
[0030] The flux is based on epoxy chemistry, for example, in order to be compatible with epoxy based underfill (if epoxy underfill is the type used). The flux often appears to be brownish tacky paste and can be applied at 25° C. using various method such as dipping, printing or pin-transferring.
[0031] Alternatively, the tacky epoxy flux can be moderately heated to achieve a proper viscosity for the flux application. In case of dipping fluxing, the pick and place arm ( 404 ) picks the chip ( 401 ) and dips the solder bumps ( 402 ) into a thin flux film on the rotary drum which has been preset at a temperature T 1 , depending on nature of flux For example, T 1 for PK-001 (an epoxy flux) is approximately 40-70 C. A sufficient amount of tacky flux ( 403 ) is picked up and transferred on the surface of solder bumps facing toward the substrate. The chip ( 401 ) is mounted onto the substrate ( 407 ) with the individual bumps ( 402 ) in contact with corresponding bonding pads ( 405 ). A thin layer of tacky flux ( 406 ) temporary holds the solder bumps ( 402 ) and bonding pads ( 405 ) together and prevents the chip ( 401 ) from shifting during the next process.
[0032] Underfill ( 408 ) is deposited along the edges of the chip in the desired pattern using a dispensing needle ( 409 ) attached to a dispensing machine. The whole device is then subjected to a heating cycle as commonly used for solder paste reflow. During this heating cycle, three major tasks are accomplished: (1) during the heating stage, the underfill material ( 408 ) flows into the gap between chip ( 401 ) and substrate ( 407 ) by capillary force and completely replaces the air in the gap prior to the solder melting, therefore leaving no air bubbles in the underfill (FIG. 3(C)), and the tacky epoxy flux ( 406 ) provides enough tack force to hold the component in place, (2) the tacky flux and fluxing component in underfill material activate the solder bump and bond pad surface on the substrate facilitating the formation of the new solder joints ( 410 ), (3) the underfill material completes curing to form a strong adhesive layer ( 411 ), thus providing mechanical, electrical, and environmental protection for the electronic device. Since the tacky flux ( 406 ) is compatible with the epoxy underfill ( 408 ), it will completely merge and react with the underfill matrix at the elevated temperature and become part of the network structure after curing, and therefore does not adversely affect the solder joints. The overall process can be simplified as:
[0033] 1. Dip fluxing at T 1 .
[0034] 2. Place chip ( 401 ) on substrate ( 407 ) at T 2 , where the temperature T 2 is not too high so that the tacky thermosettable flux ( 406 ) will provide sufficient adhesion to hold the chip ( 401 ) in place during underfilling; the tacky epoxy flux ( 406 ) also provides a physical barrier against filler penetration into the bonding area of solder bumps ( 402 ) and bond pads ( 405 ). The temperature T2 is dependent upon the type of tacky thermosettable flux chosen. For example, T2 for PK-X003 has a T2 of approximately 30-120 C, while PK-002 has a T2 of approximately 20-100 C.
[0035] 3. Underfilling, reflow soldering and underfill curing in one single reflow heating cycle. This process can be conducted in, for example, a forced air convection oven, such as a BTU VIP 70 , using a defined curing profile (e.g., ramping up linearly from room temperature to 220° C. at a ramp rate of 1° C./sec, then cooling down at a ramp rate of 2° C./sec. FIG. 7 shows an example of such a heating profile.) The tacky epoxy flux ( 406 ) will also be cured and incorporated within underfill matrix.
[0036] As an example, Flip Chip FB250 daisy chain chip was assembled using Indium tacky epoxy flux PK-X003 and Indium underfill UF-X10, 100% solder joint yield was obtained reproducibly using this process (FIG. 5(A) and (B)). FIG. 5A shows an x-ray of the completed Flip Chip using 20% filler (e.g., silica), while the chip in FIG. 5B used 40% of the filler. By comparing these 2 x-rays, we can tell that the variation in filler had no impact on the new process described herein. (I.e., the figures are similar.)
[0037] Alternatively ( 2 ), the underfilling process may be completed prior to the reflow processing as illustrated in FIG. 6. Instead of sending the device into reflow oven for the completion of underfilling, the underfill material is allowed to completely fill the gap and flow out to the edges of the chip before entering reflow process. (Note that the term “soaking” is frequently used to describe that part of the process that takes place when the product is in the oven, when the temperature is kept nearly constant, in order to allow the underfill to flow under the chip and not begin the curing process. See, for example, Stage 2 in FIG. 7.) This is especially useful when a large chip is to be underfilled as more underfill material is needed to fill the gap. Compared with option (1), the first two steps of option (2), fluxing and placement are the same as option (1) as described in FIG. 4. Following chip placement, regular underfill dispensing pattern such as one side pass, one side pass followed by another one side pass, L-type (i.e., 2 adjacent sides) pass or L-type pass followed by another L-type pass when underfill ( 601 ) flows out to the opposite side of the die is applied, the preferred dispensing pattern is selected to offer best chance to have no or minimal voids in a shortest underfilling time and create ideal fillet geometry. The substrate ( 602 ) may be heated to an elevated temperature T 2 to assist underfill ( 601 ) flow as commonly used for capillary flow underfill processing. The tacky epoxy flux ( 603 ) provides sufficient adhesion to hold the chip ( 604 ) in alignment with the substrate ( 602 ) during underfilling, preventing the chip ( 604 ) from floating and shifting. The tacky epoxy flux ( 603 ) also serves as a protective layer to prevent the filler of the underfill from interfering with solder joint formation. After this separate underfillng step, the device is subjected to a standard reflow process as used for the process of pre-deposit underfilling to establish interconnected solder joints ( 605 ) and form a desirable underfill layer ( 606 ). Compared to the capillary flow underfill processing, the present invention requires no separate fluxing and bonding processes, and flux residue cleaning step is also eliminated. The whole assembly process for Option 2 has been summarized as:
[0038] 1. Dipping fluxing at T 1 .
[0039] 2. Place chip on substrate at T 2 , where the temperature T 2 is not too high so that the tacky epoxy flux maintains sufficient bonding strength between the chip and substrate to prevent any misalignment during underfilling.
[0040] 3. Dispensing and capillary flow underfilling as used for conventional capillary flow underfill.
[0041] 4. Reflow and cure.
[0042] It is easy to understand that the process involves no placement void issue as encountered in pre-deposit underfill processing. Some other assisting measures used for capillary flow underfilling as demonstrated in existing processes are also suitable for the present invention, such as: 1. Providing a hole in the middle of substrate and allowing the underfill material to flow towards the center from entire perimeter, 2. Using dams to guide the underfill flow and apply a vacuum source to draw underfill material from one open end of the dam to the opening at the opposite end.
[0043] Application of the present invention does not restrict the means in which the tacky flux is applied. Other conventional methods such as printing, pin-transferring, dispensing, are equally applicable. Likewise, the surface to which the flux is deposited is also variable. The tacky flux can be placed on the solder bump surface facing toward the substrate or on substrate bond pads or other active surface for bonding. One way of assembling a chip is to pin transfer the tacky flux onto the bond pads of substrate, place the chip, underfill and reflow the package.
[0044] Thus it is apparent that the present invention provides an integrated processing method of assembling a solder bumped chip device that combines the advantage of void free capillary flow underfilling and integrated solder reflow and underfill cure process as further illustrated in FIG. 7. While the invention has been described and illustrated with reference to the preferred embodiments, it is not intended to restrict or in any way limit the scope of the present invention. It is common to those skilled in the art to have additional modifications, variations, substitutions and equivalents in practicing the invention without departing from the spirit of current invention as defined by the appended claims. | An integrated void-free process has been developed for attaching a solder bumped chip to a substrate. The chip is first dipped in a tacky thermosettable flux, and the chip is mounted on the substrate. An underfill is dispensed along the edge of the chip The device is then sent into the reflow furnace to complete the underfilling (which optionally can be completed before reflow), solder reflowing and underfill curing. The flux also acts as a physical barrier minimizing, if not eliminating, the interference of filler on solder wetting and resulting metallurgical joints formed between the solder and the bond pads. The process allows for the integration of a void free conventional capillary flow underfilling process and a pre-deposited fluxing underfilling process by using a tacky thermosettable flux, avoiding the problems associated with each of the individual processes and requiring less time for the overall process. | Summarize the patent information, clearly outlining the technical challenges and proposed solutions. | [
"CROSS REFERENCE TO RELATED APPLICATIONS [0001] N/A STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] N/A BACKGROUND OF THE INVENTION [0003] This invention relates generally to a method of assembling a semiconductor chip electrically and mechanically connected to a substrate, particularly in a flip chip configuration.",
"[0004] Assembly of solder bumped chips such as flip chip or chip scale package (SCP) is an emerging technology which satisfies the demands of the ever-increasing requirements for high I/O density, small form factor, and improved performance in integrated circuit (IC) design.",
"In the process of chip assembly, a chip is mounted on a substrate with any kind of interconnect material.",
"Among the many kinds of interconnect materials, solder has remained a predominant choice.",
"Solder bumped chip assembly consists two major steps: (1) chip soldering and (2) underfill encapsulation.",
"To attach chip to the substrate, a flux is applied to the substrate or solder bumps on the chip.",
"The chip is then aligned with the bond pads on the substrate, placed, and reflowed, forming electrical connections and mechanical joints between flip chip and substrate.",
"After soldering a solvent cleaning step is usually involved to remove the flux residue which otherwise weakens the underfill adhesion which in turn degrades solder joint reliability.",
"The cleaning process is a difficult operation, often costly and time consuming, involving solvents and expensive equipments.",
"Therefore, there is a need to develop a new technology that does not require this cleaning process.",
"[0005] Another issue in the implementation of solder bumped chip technology when applied to organic polymer substrate is the mismatch of the coefficient of thermal expansion (CTE) of the chip, and that of the substrate having a higher CTE.",
"The build up stress on solder joints upon thermal excursions experienced during the application of the device causes solder joint fatigue and leads to the failure of the interconnect joints.",
"To minimize this problem, an underfill material is applied in the interspace of chip and substrate after chip soldering to assure the reliability and electric integrity.",
"The traditional underfill material is typically a highly flowable liquid formulation, containing filler particles to reduce CTE.",
"The underfill material is dispensed along the edges of the chip and allowed to wick into the space between the substate and the chip.",
"The capillary action allows the underfill to flow out to the opposite sides of the chip and completely fill the gap between the chip and the substrate.",
"Even though the substrate is usually heated to an elevated temperature to facilitate the underfill flow, the process still takes more than seconds to completely underfill the chip, which is considered a bottle neck in manufacturing process.",
"After underfilling, the package is subjected to an elevated temperature for underfill curing.",
"The cured underfill material redirects or redistributes the stress away from tiny solder joints, thus enhancing the package reliability.",
"In addition, underfill materials also serve as mechanical and environmental protection, which increases the resistance to shock, vibration, moisture, solvent, and provide thermal dissipation between chip and substrate.",
"[0006] While traditional capillary flow underfill materials with reduced flow and cure time are dominant in current underfill applications, the use of so-called pre-deposit fluxing underfill offers an attractive alternative which would speed up package processing and enhance compatibility with surface mount technology (SMT).",
"In addition to bearing the functions provided by traditional underfill encapsulant, the pre-deposit underfill materials are integrated with fluxing capability.",
"The overall assembly process based on this type of underfill material is simplified by combining three basic steps: (1) underfill dispensing, (2) chip placement, and (3) reflow.",
"During reflow, the fluxing agent incorporated in underfill materials provides sufficient activity to remove surface oxide on solder bumps and bond pads, forming interconnect joints.",
"In the meantime, the underfill material is chemically crosslinked, forming a strong network structure providing mechanical and environmental protection as described for traditional underfill encapsulation.",
"The benefits of the pre-deposit underfill process are well explored in the recent years.",
"These include simpler process to control, higher throughput, self-fluxing action, etc.",
"Even though there has been an explosion of interest and great effort to develop this technology throughout the past decade, the use of pre-deposit underfill is, however, not without its inherent problems and limitations.",
"One of the obstacles which pre-deposited fluxing underfill materials must overcome, is placement of the component without void entrapment.",
"A direct consequence of underfill pre-deposit followed by fast paced chip placement (less then a second), is that the underfill material is forced to flow toward the periphery of the chip in such a short time that air is entrapped around solder bumps (FIG.",
"2).",
"These air bubbles will generate internal vapor pressure when the temperature increases during reflow, leading to process failures such as chip float and misalignment of solder bumps relative to the matching bond pads.",
"Furthermore, the trapped air bubbles around solder joints pose a great threat to the solder joint performance, defects such as irregularity, solder extrusion, incomplete wetting, voids inside joint are often encountered.",
"Yet, another challenge of developing such pre-deposit fluxing underfill materials is the interference of inorganic filler particles on soldering during reflow as solid filler particles will inhibit the solder wetting on bonding pads.",
"How to incorporate fillers into pre-deposit fluxing underfill to reduce CTE and apply such pre-deposit underfill in manufacture processing remains uncertain.",
"As a result, the pre-deposit underfill typically contains no filler, thus has a CTE much higher than that of capillary flow underfill and therefore unparallel performance.",
"[0007] It would be desirable to develop a method that takes advantages of capillary flow underfill process, such as void free, low CTE, widely accepted industry processing practice, and combines the attractive features of fluxing underfill such as shorter manufacturing cycle, no cleaning step required, underfill cured in the same step as solder reflow, and SMT processing compatibility.",
"Such a processing method should yield overall higher efficiency, and low cost without compromising the reliability and performance.",
"BRIEF SUMMARY OF THE INVENTION [0008] The present invention provides a method of assembling a substrate and an IC die in a flip chip configuration using a tacky thermosettable flux and underfilling such a device.",
"According to the present invention, as described in the illustrated embodiments, a thin layer of tacky flux is applied to the substrate or preferably to the solder bumps, a chip is placed on the substrate with the solder bumps in contact with the matching bonding pads.",
"The tacky flux provides temporary adhesive bonding to immobilize the chip.",
"An underfill is then dispensed along the edges of the chip and the whole package is transferred to reflow process.",
"During solder reflow process, three major processing tasks are accomplished in one single step: (1) the underfill flows into the gap between chip and substrate and completely fills the interspace, (2) the tacky flux activates the bonding surface and facilitates solder reflow and joint formation, (3) underfill curing.",
"Because tacky flux is formulated to be compatible with underfill, it is chemically incorporated into the cured underfill network structure.",
"[0009] In one aspect of present invention there is provided an integrated method of underfilling a device on a substrate during reflow process.",
"The method comprises applying tacky flux to solder bumps or substrate to be joined and placing the chip on substrate so that the chip is temporarily held in place.",
"The underfill is deposited on the substrate along the edges of the chip and the whole device is subjected to a reflow process.",
"In general, a reflow process can be roughly divided into four major stages: heating stage, soaking stage, and the reflow and cooling stage.",
"The viscosity of underfill material is reduced as the temperature of the whole device is gradually increased in the heating stage, this will facilitate the underfill to flow into the gap, as a result, the gap is completely filled with underfill material before the temperature reaches the solder melting point.",
"Because the underfill is allowed to flow, via capillary action, into the gap between chip and substrate, the underfill material is able to wet any surface in contact and replace the air space underneath the die with underfill material, avoiding the formation of air bubbles.",
"The incorporation of underfilling into the solder reflow process removes the typical bottleneck of the manufacturing process, thus significantly shortening the manufacturing cycle.",
"[0010] Another aspect of the present invention is increased gap height during the underfilling process.",
"Because the device is underfilled before reflow and solder collapse, the maximum clearance between chip and substrate for the underfill process is increased.",
"The size of the gap is controlled by the height of solder bumps and typically varies from 3 to 30 mils.",
"With the increase of I/O density in IC devices, the solder bumps (i.e., the clearance between the chip and the substrate) are becoming even smaller.",
"This reduced height presents a greater challenge for the underfill, making capillary flow more difficult and increasing the time needed to fill the gap.",
"Typically, depending on the pad design and layout, there is a 15-30% drop in the clearance after solder reflow in C4 (controlled collapse chip connection) process, this clearance drop further increases the chance of introducing underfill defects such as voids, filler segregation, and increased flow time.",
"Underfilling before soldering provides the maximum clearance for the underfilling process.",
"[0011] In another aspect of present invention, a uniform fillet is formed after solder reflow.",
"Traditional process of chip bonding first followed by underfill dispensing tends to create a non-uniform fillet around the chip.",
"Typically, the fillet will be large enough on the one or two sides of chip where the underfill is originally dispensed and there is not enough underfill material flowing out to the other sides of the chip to form a desirable fillet profile.",
"An additional dispensing operation is usually required to compensate the material deficiency on the other sides, which also brings in additional manufacturing time.",
"Underfilling before solder collapse assures the formation of uniform fillet.",
"Upon solder collapse, the chip will force the additional underfill material to flow out to the edges of the chip, providing enough material to form a desirable fillet.",
"[0012] In another aspect of present invention, a tacky flux is provided to block the interference of filler particles on the solder joint formation.",
"The current process of pre-deposit fluxing underfill does not allow the use of underfill material with a high percentage of filler to achieve a sufficiently low CTE, usually around 25-45 ppm/° C. Use of high percentage of filler content inhibits solder wetting on bond pads, thus preventing the formation of a desirable solder joint.",
"This is why current formulations of this type of pre-deposit fluxing underfill usually contain no or very low percentages of fillers.",
"The resulted high CTE of the material limits the performance of the final package.",
"The process of the present invention takes advantage of tacky flux to prevent the interference of filler during solder reflow, with the tacky flux forming a thin layer adhering to the contacting bump and pad, and acting as a physical barrier to the filler intrusion.",
"A 100% interconnect yield can be achieved reproducibly.",
"BRIEF DESCRIPTION OF THE FIGURES [0013] [0013 ]FIG. 1 is a process flow chart illustrating the steps for assembling a chip and substrate in accordance with conventional capillary flow underfill process.",
"[0014] [0014 ]FIG. 2 is a process flow chart illustrating the steps for assembling a chip and substrate in accordance with pre-deposit fluxing underfill process.",
"[0015] [0015 ]FIG. 3 is the comparison of entrapped voids after chip placement on glass substrate using different process: (A) pre-deposit underfill process, (B) pre-deposit underfill process after cure, and (C) the present integrated process.",
"Flip Chip Technology FA10-200 on glass substrate with 5 mil bump diameter and 10 mil pitch is used for this illustration.",
"[0016] [0016 ]FIG. 4 is a process flow chart illustrating the steps for assembling a chip and in accordance with present invention-option 1.",
"[0017] [0017 ]FIG. 5 is the x-ray images of assembled Flip Chip FB250 with organic surface protection (OSP) coating on pads using the process in accordance with the present invention-option 1.",
"Indium tacky epoxy flux PK-X003 and underfill UF-X10 containing 20% filler (A) and 40% filler (B) is used for this illustration.",
"[0018] [0018 ]FIG. 6 is a process flow chart illustrating the steps for assembling a chip and substrate in accordance with present invention-option 2.",
"[0019] [0019 ]FIG. 7 shows the integration of underfill, curing and solder bump reflow into one reflow step.",
"The underfilling process can be completed in a reflow oven or before the package is sent into a reflow oven.",
"Also shown is the typical reflow profile described in four stages: (1) heating stage, (2) soaking stage, (3) reflow and (4) cooling stage.",
"DETAILED DESCRIPTION OF THE INVENTION [0020] A new integrated void free process for assembling solder bumped chips such as flip chip or chip scale packages (CSP) using a tacky thermosettable flux is provided.",
"The tacky flux is not only sufficiently tacky to keep the chip attached to the substrate while other processing (e.g., addition of the underfill) takes place, but also fully compatible with underfill and will not cause delamination.",
"The traditional tacky fluxes were generally incompatible with underfills and caused delamination of the underfills.",
"They were used with “regular”",
"soldering, processes in which underfills were not used.",
"These traditional products contained much resin (which added the stickiness to the product), along with solvent and activator.",
"[0021] By tacky thermosettable flux, we mean a flux which is flowable before reflow, provides good flux properties (e.g., removal of oxides, etc.), and, after reflow, is cross-linked to form a thermosetting polymer.",
"Examples of tacky thermosettable flux include epoxy fluxes, polyimide fluxes, polyacrylate fluxes, polyurethane fluxes, and combinations thereof.",
"Other polymers that perform similarly also can be used, either individually or in combination with other such fluxes.",
"[0022] Furthermore, the area of prime interest herein is the new process that results from use of the new tacky thermosettable flux.",
"As indicated in more detail below, the new process allows the combination of several steps that were previous conducted separately, thus simplifying the underfilling, reflow and curing steps.",
"Furthermore, the resulting IC has a much lower failure rate, due to the absence of underfill voids in the new process.",
"It should be noted that, although several tacky fluxes are disclosed herein, the new process is not confined to the use of those fluxes.",
"Instead, any flux that is sufficiently sticky to hold the chip to the substrate during the steps discussed can be used in the new process.",
"(I.e., the flux must be sufficiently sticky to prevent the component from floating away.) [0023] The tacky flux is first applied to the solder bumps or substrate using conventional methods followed by placement of the chip onto the substrate so that the solder bumps are in contact with the substrate bond pads.",
"The underfill is then dispensed along the edges of the chip and the device is transferred to a reflow cycle.",
"During the reflow heating, the underfill material flows into the space between chip and substrate, driven by capillary action, leaving no entrapped voids in the underfill.",
"In the meantime, the device is reflowed and cured.",
"The tacky epoxy flux is designed to provide temporary adhesion between the electronic components and substrate as well as provide fluxing activity for soldering during reflow.",
"The tacky flux can be composed of one or more fluxing agents and a combination of epoxy (or other fluxes listed above), hardener, and/or curing agent.",
"The tacky epoxy flux is formulated to have similar chemical nature as epoxy based underfill materials and thereby will be incorporated into the final polymer network structure through diffusion and chemical reaction after reflow, without deterioration of the underfill performance.",
"The tackiness is provided by the high molecular weight epoxy, hardener, or the combination of the two.",
"The new process consolidates underfilling, solder reflow, and underfill curing into a one-step reflow process, thereby simplifying the flip chip packaging process which otherwise requires separate solder reflow and underfilling steps.",
"The new process combines the advantages of conventional void free capillary flow underfill process and simple pre-deposit fluxing underfill process, and therefore optimizes the manufacturing process without compromising any performance requirements.",
"The tacky flux will prevent the chip from floating, which will cause misalignment between bond pad and solder bumps.",
"The sequence of underfilling before solder reflow facilitates underfill flow because of the increased clearance between the chip and substrate created by the unreflowed solder bumps.",
"[0024] [0024 ]FIG. 1 illustrates the typical process of assembling a chip and a substrate or chip carrier by conventional capillary flow underfilling.",
"The substrate ( 101 ) typically comprises silicon, ceramic, glass, FR-4, BCB, polyimide, or combination thereof, and is fabricated as printed circuit board (PCB) or chip carrier used in flip-chip technology.",
"The substrate has coplanar metallurgical bond pads ( 102 ).",
"The flux is applied to the substrate as a thin film ( 103 ) using various flux application methods such as spray, brushing, pin transferring and printing.",
"Alternatively, the flux can be applied to the solder bumps attached to the flip chip by dipping the solder bumps into a thin layer of flux on a motorized flux tray (not shown).",
"The bumps can be Pb-based or Pb-free solder alloys.",
"A chip ( 104 ) is shown mounted on a substrate ( 101 ) with solder bumps ( 105 ) connected to the chip aligned with the bond pads ( 102 ) of the substrate ( 101 ).",
"During reflow, the flux ( 103 ) removes the oxide on the surface of solder bumps ( 105 ) attached to the chip ( 104 ) and the oxide on the bond pads ( 102 ) on the substrate ( 101 ), a mechanical and electrical solder joint ( 106 ) is thus formed between chip ( 104 ) and substrate ( 101 ).",
"The chip/substrate combination is cleaned to remove the flux residue ( 107 ) which otherwise, will hinder the underfill flow and degrade the adhesion of underfill to the substrate, chip and solder joints.",
"An underfill material ( 108 ) is dispensed through a needle ( 109 ) and deposited along the edges of bonded chip using predetermined patterns such as one-side, L type pattern, double L pass, or L pass followed by another L pass on the opposite sides.",
"The underfill material ( 108 ) is allowed to wick into the gap formed between bottom side of the chip and the top of the substrate by capillary action.",
"The underfill flow process is usually facilitated by heating the substrate to a temperature T2, which is dependent upon the flux used and is described in more detail later herein.",
"Generally, the temperature is between approximately 20 and 130° C. The flow process can be completed in a matter of seconds depending on chip size, clearance between chip and substrate, I/O density, and the selected underfill material.",
"As the result of capillary flow, the underfill material is able to replace any air in the interspace between chip and substrate.",
"After underfilling, the whole device is subjected to a high temperature curing process which can be varied from few minutes to few hours.",
"A mechanically strong and stable adhesive layer ( 110 ) is formed between chip and substrate, providing stress relief and environmental protection to the package.",
"[0025] While conventional capillary flow underfills now possess improved flow speed and cure rate, they still require a few more processing steps beyond the typical SMT process which typically consists of solder paste or flux deposition, component placement, and reflow soldering.",
"In recent years, pre-deposit fluxing underfill materials have been extensively explored in order to meet the demand of low cost, high throughput, and SMT compatibility.",
"The overall manufacturing process is simplified significantly as illustrated in FIG. 2. The underfill material ( 201 ) is deposited, in a desired pattern, onto the substrate ( 202 ), which has been baked beforehand to release any surface moisture.",
"A solder bumped chip ( 203 ) is mounted onto the substrate with solder bumps ( 204 ) aligned to the corresponding bond pads of the substrate ( 205 ) in a one-to-one fashion.",
"During the same reflow process as used for reflowing solder paste, the underfill material ( 206 ) provides the fluxing capability to assist the formation of solder joint ( 208 ) and undergoes a curing reaction to form a protective underfill layer ( 209 ).",
"Although extensive effort has been made to promote this technology, many problems still exist as this moves into real world of applications.",
"One of the inherent problems is the void entrapped during chip placement.",
"This is because the underfill material ( 206 ) is unable to fully wet the surface and expel the air out of the space between chip and substrate before fast paced chip placement (typically less than one second) is completed.",
"A confined air bubble ( 207 ) is formed around the corner of each individual solder bump, mostly behind solder bumps along the underfill flow direction.",
"This situation becomes more significant when a fully populated area array solder bumped chip is used as demonstrated in FIG. 3(A).",
"These air bubbles, with diameters about one-third to half the diameter of solder balls, pose a great threat to the integrity of solder joint reliability.",
"Solder joint failure such as solder extrusion, and joint cracking has been reported due to the presence of these voids ( 210 ) in the cured underfill.",
"The situation can be worsened when these air bubbles expand and/or merge to form bigger bubbles (FIG.",
"3(B)), thus causing a greater chance of chip floating or solder joint failure.",
"[0026] The present invention provides an integrated solution to the problems associated with the prior art and takes advantages of capillary flow void free underfilling and a simplified manufacturing process.",
"These advantages will be made clear in the following detailed description and accompanying drawings of the present invention.",
"[0027] Illustrated in FIG. 4 is representative of the processes for assembling a chip in accordance with the present invention.",
"The process begins with the application of tacky epoxy flux ( 403 ) on either substrate ( 407 ) or solder bumps ( 402 ) attached to a chip ( 401 ).",
"There are several methods available for applying tacky flux to a substrate or solder bumps.",
"For examples, brushing, printing, spraying, roller coating, pin transferring, or dispensing are well known techniques used in this field.",
"Another method, often called flux dipping, involves the use of rotary drum having a doctor blade to control the flux thickness.",
"The rotary drum has a temperature controller, providing a proper viscosity, to enable a high volume manufacturing process.",
"These rotary drum flux applicators are readily available from pick and place machine vendors.",
"The tacky epoxy flux has sufficient chemical activity to activate solder bumps to form reliable solder joints with bond pads, sufficient tacky force to adhere the substrate and pre-aligned chip during underfilling, and a proper viscosity to enable high volume manufacturing process.",
"The tacky epoxy flux is typically composed of one or more fluxing agents, and a combination of tacky epoxy, hardener, and/or curing agent.",
"(As indicated above, other types of fluxes, such as polyimide fluxes, can also be utilized.) The tacky flux is formulated with compositions compatible with or similar to underfill composition and therefore will be incorporated into the adhesive network structure after reflow heating cycle.",
"In this context the word compatible means that the tacky fluxs are composed of chemicals which are reactive to the epoxy or other compositions in underfill material.",
"During reflow heating, the tacky flux is solublized in the underfill material and become a part of the net work structure after curing.",
"[0028] Examples of tacky fluxes include PK-001 and PK-002, products sold by Indium Corporation of America.",
"One example of a tacky epoxy flux that can be applied at an ambient temperature is PK-X003 manufactured by Indium Corporation of America, the room temperature Brookfield viscosity of this material is around 50000 cps.",
"However, it should be emphasized that other tacky fluxes can also be used.",
"[0029] One example of an underfill that can be used along with this epoxy flux is UF-X10, also manufactured by Indium Corporation of America.",
"The Brookfield viscosity of this underfill is around 3000 cps at room temperature.",
"Note that the underfill can contain additional flux to further improve the efficiency of the reflow process.",
"[0030] The flux is based on epoxy chemistry, for example, in order to be compatible with epoxy based underfill (if epoxy underfill is the type used).",
"The flux often appears to be brownish tacky paste and can be applied at 25° C. using various method such as dipping, printing or pin-transferring.",
"[0031] Alternatively, the tacky epoxy flux can be moderately heated to achieve a proper viscosity for the flux application.",
"In case of dipping fluxing, the pick and place arm ( 404 ) picks the chip ( 401 ) and dips the solder bumps ( 402 ) into a thin flux film on the rotary drum which has been preset at a temperature T 1 , depending on nature of flux For example, T 1 for PK-001 (an epoxy flux) is approximately 40-70 C. A sufficient amount of tacky flux ( 403 ) is picked up and transferred on the surface of solder bumps facing toward the substrate.",
"The chip ( 401 ) is mounted onto the substrate ( 407 ) with the individual bumps ( 402 ) in contact with corresponding bonding pads ( 405 ).",
"A thin layer of tacky flux ( 406 ) temporary holds the solder bumps ( 402 ) and bonding pads ( 405 ) together and prevents the chip ( 401 ) from shifting during the next process.",
"[0032] Underfill ( 408 ) is deposited along the edges of the chip in the desired pattern using a dispensing needle ( 409 ) attached to a dispensing machine.",
"The whole device is then subjected to a heating cycle as commonly used for solder paste reflow.",
"During this heating cycle, three major tasks are accomplished: (1) during the heating stage, the underfill material ( 408 ) flows into the gap between chip ( 401 ) and substrate ( 407 ) by capillary force and completely replaces the air in the gap prior to the solder melting, therefore leaving no air bubbles in the underfill (FIG.",
"3(C)), and the tacky epoxy flux ( 406 ) provides enough tack force to hold the component in place, (2) the tacky flux and fluxing component in underfill material activate the solder bump and bond pad surface on the substrate facilitating the formation of the new solder joints ( 410 ), (3) the underfill material completes curing to form a strong adhesive layer ( 411 ), thus providing mechanical, electrical, and environmental protection for the electronic device.",
"Since the tacky flux ( 406 ) is compatible with the epoxy underfill ( 408 ), it will completely merge and react with the underfill matrix at the elevated temperature and become part of the network structure after curing, and therefore does not adversely affect the solder joints.",
"The overall process can be simplified as: [0033] 1.",
"Dip fluxing at T 1 .",
"[0034] 2.",
"Place chip ( 401 ) on substrate ( 407 ) at T 2 , where the temperature T 2 is not too high so that the tacky thermosettable flux ( 406 ) will provide sufficient adhesion to hold the chip ( 401 ) in place during underfilling;",
"the tacky epoxy flux ( 406 ) also provides a physical barrier against filler penetration into the bonding area of solder bumps ( 402 ) and bond pads ( 405 ).",
"The temperature T2 is dependent upon the type of tacky thermosettable flux chosen.",
"For example, T2 for PK-X003 has a T2 of approximately 30-120 C, while PK-002 has a T2 of approximately 20-100 C. [0035] 3.",
"Underfilling, reflow soldering and underfill curing in one single reflow heating cycle.",
"This process can be conducted in, for example, a forced air convection oven, such as a BTU VIP 70 , using a defined curing profile (e.g., ramping up linearly from room temperature to 220° C. at a ramp rate of 1° C./sec, then cooling down at a ramp rate of 2° C./sec.",
"FIG. 7 shows an example of such a heating profile.) The tacky epoxy flux ( 406 ) will also be cured and incorporated within underfill matrix.",
"[0036] As an example, Flip Chip FB250 daisy chain chip was assembled using Indium tacky epoxy flux PK-X003 and Indium underfill UF-X10, 100% solder joint yield was obtained reproducibly using this process (FIG.",
"5(A) and (B)).",
"FIG. 5A shows an x-ray of the completed Flip Chip using 20% filler (e.g., silica), while the chip in FIG. 5B used 40% of the filler.",
"By comparing these 2 x-rays, we can tell that the variation in filler had no impact on the new process described herein.",
"(I.e., the figures are similar.) [0037] Alternatively ( 2 ), the underfilling process may be completed prior to the reflow processing as illustrated in FIG. 6. Instead of sending the device into reflow oven for the completion of underfilling, the underfill material is allowed to completely fill the gap and flow out to the edges of the chip before entering reflow process.",
"(Note that the term “soaking”",
"is frequently used to describe that part of the process that takes place when the product is in the oven, when the temperature is kept nearly constant, in order to allow the underfill to flow under the chip and not begin the curing process.",
"See, for example, Stage 2 in FIG. 7.) This is especially useful when a large chip is to be underfilled as more underfill material is needed to fill the gap.",
"Compared with option (1), the first two steps of option (2), fluxing and placement are the same as option (1) as described in FIG. 4. Following chip placement, regular underfill dispensing pattern such as one side pass, one side pass followed by another one side pass, L-type (i.e., 2 adjacent sides) pass or L-type pass followed by another L-type pass when underfill ( 601 ) flows out to the opposite side of the die is applied, the preferred dispensing pattern is selected to offer best chance to have no or minimal voids in a shortest underfilling time and create ideal fillet geometry.",
"The substrate ( 602 ) may be heated to an elevated temperature T 2 to assist underfill ( 601 ) flow as commonly used for capillary flow underfill processing.",
"The tacky epoxy flux ( 603 ) provides sufficient adhesion to hold the chip ( 604 ) in alignment with the substrate ( 602 ) during underfilling, preventing the chip ( 604 ) from floating and shifting.",
"The tacky epoxy flux ( 603 ) also serves as a protective layer to prevent the filler of the underfill from interfering with solder joint formation.",
"After this separate underfillng step, the device is subjected to a standard reflow process as used for the process of pre-deposit underfilling to establish interconnected solder joints ( 605 ) and form a desirable underfill layer ( 606 ).",
"Compared to the capillary flow underfill processing, the present invention requires no separate fluxing and bonding processes, and flux residue cleaning step is also eliminated.",
"The whole assembly process for Option 2 has been summarized as: [0038] 1.",
"Dipping fluxing at T 1 .",
"[0039] 2.",
"Place chip on substrate at T 2 , where the temperature T 2 is not too high so that the tacky epoxy flux maintains sufficient bonding strength between the chip and substrate to prevent any misalignment during underfilling.",
"[0040] 3.",
"Dispensing and capillary flow underfilling as used for conventional capillary flow underfill.",
"[0041] 4.",
"Reflow and cure.",
"[0042] It is easy to understand that the process involves no placement void issue as encountered in pre-deposit underfill processing.",
"Some other assisting measures used for capillary flow underfilling as demonstrated in existing processes are also suitable for the present invention, such as: 1.",
"Providing a hole in the middle of substrate and allowing the underfill material to flow towards the center from entire perimeter, 2.",
"Using dams to guide the underfill flow and apply a vacuum source to draw underfill material from one open end of the dam to the opening at the opposite end.",
"[0043] Application of the present invention does not restrict the means in which the tacky flux is applied.",
"Other conventional methods such as printing, pin-transferring, dispensing, are equally applicable.",
"Likewise, the surface to which the flux is deposited is also variable.",
"The tacky flux can be placed on the solder bump surface facing toward the substrate or on substrate bond pads or other active surface for bonding.",
"One way of assembling a chip is to pin transfer the tacky flux onto the bond pads of substrate, place the chip, underfill and reflow the package.",
"[0044] Thus it is apparent that the present invention provides an integrated processing method of assembling a solder bumped chip device that combines the advantage of void free capillary flow underfilling and integrated solder reflow and underfill cure process as further illustrated in FIG. 7. While the invention has been described and illustrated with reference to the preferred embodiments, it is not intended to restrict or in any way limit the scope of the present invention.",
"It is common to those skilled in the art to have additional modifications, variations, substitutions and equivalents in practicing the invention without departing from the spirit of current invention as defined by the appended claims."
] |
RELATED APPLICATIONS
[0001] This application is related to the following co-pending applications, all filed on the same day and naming the same inventors as this application: “Processing a Spread Spectrum Signal in a Frequency Adjustable System”; “Bandpass Correlation of a Spread Spectrum Signal”; “Acquiring a Spread Spectrum Signal”; and “Receiving a Spread Spectrum Signal”.
BACKGROUND OF THE INVENTION
[0002] The invention relates to processing a spread spectrum signal.
[0003] In wireless systems, information typically is transmitted by modulating the information onto carrier waves having frequencies that lie within preassigned frequency bands. Radio frequency (RF) receivers demodulate the carrier waves to recover the transmitted information.
[0004] Spread spectrum communication systems spread transmitted signals over bandwidths much larger than those actually required to transmit the information. Spreading a signal over a wide spectrum has several advantages, including reducing the effects of narrow band noise on the signal and, in many situations, providing increased protection against interception by unwanted third parties. In a direct sequence spread spectrum (DSSS) system, the bandwidth of a transmitted signal is increased by modulating the signal onto a known pseudo-noise (PN) signal before modulating onto the carrier wave. The PN signal typically is a digital signal having an approximately equal number of high and low bits (or “chips”), which maximizes the spectrum over which the signal is spread. A typical implementation of a DSSS receiver recovers the transmitted information by demodulating the carrier wave and then multiplying the resulting signal with a local replica of the PN signal to eliminate the PN signal. The DSSS technique offers heightened security because the receiver must know the PN sequence used in the transmission to recover the transmitted information efficiently. Other spread spectrum techniques include frequency hopped spread spectrum (FHSS).
SUMMARY OF THE INVENTION
[0005] In one aspect, the invention features processing a spread spectrum signal digitally sampled at a selected sampling rate. The digitally sampled signal is received and despread at a center frequency lower than the sampling rate and higher than zero, and is accumulated at the center frequency.
[0006] Embodiments of the invention may include one or more of the following features. The center frequency may be limited to no greater than approximately one-half of the sampling rate, and it may be set to equal approximately one-quarter of the sampling rate. A DC filter may be used to filter any DC offset from the digitally sampled spread spectrum signal. The center frequency may be selected SO that no data embedded in the spread spectrum signal is blocked by the DC filter. The spread spectrum signal may include a pseudo-noise (PN) spreading sequence, and the reference signal may contain the PN spreading sequence.
[0007] Advantages of the invention may include one or more of the following. A spread spectrum signal may be processed without demodulating the signal to DC until the processing is complete. An AC-coupled filter or other DC block may be used to eliminate DC offset from the spread spectrum signal before it is processed. A direct sequence spread spectrum signal may be processed using a correlator with an implementation efficient structure, which will lower the cost of receivers in which the invention is used and improve the efficiency of such receivers.
[0008] Other advantages of the invention will become apparent from the following description and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the general description above and the detailed description below, serve to explain the principles and advantages of the invention.
[0010] [0010]FIG. 1 is a block diagram of a wireless local area network (LAN).
[0011] [0011]FIG. 2 is a block diagram of a transceiver for use in a wireless Network such as that shown in FIG. 1.
[0012] [0012]FIG. 3 is waveform illustrating one period of a 63-chip PN sequence.
[0013] [0013]FIG. 4 is chart showing the code phases of a possible 16-CCSK alphabet generated from a 63-chip PN sequence.
[0014] [0014]FIG. 5 is a diagram showing the components of an information packet transmitted in a spread spectrum communication system using CCSK modulation.
[0015] [0015]FIG. 6 is a block diagram of a receiver for use in a spread spectrum communication system.
[0016] [0016]FIGS. 7A and 7B are flow diagrams of the operation of the receiver of FIG. 6 during search, acquisition, and demodulation of spread spectrum signals.
[0017] [0017]FIGS. 8A and 8B are block diagrams of implementation efficient correlators for use in recovering data from spread spectrum signals.
[0018] [0018]FIG. 9 is a schematic diagram of a sign inverter for use in the correlator of FIG. 8 in recovering data modulated onto direct sequence spread spectrum signals using cyclic code shift keying (CCSK) modulation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Referring to FIG. 1, spread spectrum technology is particularly suited for use in a wireless network 30 in which many devices (e.g., radios) transmit different streams of information within a relatively small geographic area. The wireless network 30 may be used in remote monitoring applications, e.g., by large utility companies to monitor resource consumption remotely. A network 30 used in such a manner typically consists of a large number of endpoint devices 32 , such as devices that record resource consumption at utility meters (e.g., electricity meters) located at business and residential structures throughout a metropolitan area. The endpoint devices 32 gather information and, using internal wireless radio transceivers (not shown in the figure), periodically transmit the information as digital data packets through a hierarchical network to a system controller 34 . System controller 34 typically includes a network server computer (not shown in the figure) that may distribute the information to clients 36 on a computer network 38 . In larger metropolitan areas, endpoint devices 32 in the wireless network 30 may be organized into “cells” 40 , which may be divided into “microcells” 42 . Typically, microcells 42 cover relatively small geographic areas of similar size or containing a similar number of endpoint devices 32 . Each cell 40 is governed by a cell master 44 , which oversees operation of the endpoint devices 32 within the cell 40 and relays information between the system controller 34 and the endpoint devices 32 in the cell 40 . Likewise, each microcell 42 is governed by a microcell controller 46 , which supervises the operation of all endpoint devices 32 in the microcell 42 and which relays information between the corresponding cell master 44 and the endpoint devices 32 in the microcell 42 .
[0020] The wireless network 30 should include as few microcell controllers 46 as possible since each controller 46 adds to the total cost of installing and administering the network 30 . The number of microcell controllers 46 required in a given geographical area depends upon the minimum signal strength (“sensitivity”) at which each controller 46 can recover information contained in transmissions from the endpoint devices 32 in the corresponding microcell 42 . The cost of the wireless network 30 may be reduced and its dynamic capabilities may be expanded if the wireless radios used in the communicating devices (e.g., system controller 34 , cell masters 44 , microcell controllers 46 , and endpoint devices 32 ) in the network 30 were to include more efficient components than those currently available.
[0021] The invention is suited for use in a wireless network such as that shown in FIG. 1 and in direct sequence spread spectrum (DSSS) systems in which cyclic code shift keying (CCSK) is used to modulate digital data onto digital pseudo-noise (PN) spreading sequences. CCSK is a modulation technique in which circular phase shifts of a PN sequence are used to represent the possible constellation (or data) symbols. For example, a 63-chip PN sequence could support up to 63 different data symbols, each of which would be 63-chips in length. An M-CCSK constellation (or alphabet) is a group of M CCSK data symbols, each representing a unique combination of binary data bits, where M is an integer greater than one. Spread spectrum communication systems using CCSK and related data modulation techniques are described in U.S. Pat. No. 4,707,839, issued to Andren et al., on Nov. 17, 1987, and U.S. Pat. No. 4,730,340, issued to Frazier, Jr., et. al, on Mar. 8, 1988, both of which are incorporated herein by reference. The invention will be described in the context of a DSSS system using CCSK data modulation, but the invention is not limited to use in such a system.
[0022] Referring also to FIG. 2, each radio in the system controller 34 , cell masters 44 , microcell controllers 46 , and endpoint devices 32 of the DSSS wireless network 30 of FIG. 1 includes a transmitter 50 and a receiver 52 equipped to send and receive, respectively, spread spectrum signals carrying information encoded onto a PN sequence with CCSK modulation. In the transmitter 50 , data to be transmitted is generated by a computing device, such as a microprocessor 54 . A digital hardware block 56 receives the data, along with instructions for processing it, from the processor 54 and modulates the data onto a predetermined PN sequence to form a spread spectrum signal. An RF hardware block 58 then modulates the spread spectrum signal onto an RF carrier wave (e.g., a wave in the ISM band ranging from 902 MHZ to 928 MHZ), the frequency of which is determined by frequency synthesizer 60 , and transmits the combined signal over a wireless transmission channel 62 . The transmitter 50 also may include a spectral enrichment block 64 , which further improves the transmitter's spreading qualities by modulating an additional PN sequence over the CCSK modulated primary PN sequence, as discussed below.
[0023] The transmitted RF signal is received by the receiver 52 and may be down converted to an intermediate frequency (IF) by an RF hardware block 66 controlled by a local oscillator (LO) 68 . The intermediate frequency is selected according to the following equation:
IF=F s ·( N± ¼),
[0024] where F s is the sampling rate of an A/D converter (discussed below) and N is an integer. A digital hardware block 70 in the receiver 52 samples the IF signal and converts the samples to digital representation. The digital hardware block 70 then demodulates the spread spectrum signal to recover the encoded digital data. A processor 72 in the receiver controls the operation of the digital hardware block 70 and uses the recovered data as specified by firmware and software associated with the processor 72 . Within each device in the wireless network 30 , a single processor may be used to control both the transmitter 50 and the receiver 52 .
[0025] The primary PN sequence (or “code”) used to create the spread spectrum signal consists of a predetermined number of repeating binary code bits (or “chips”), approximately half of which have a binary value of “1” and the rest of which have a binary value of “−1”. Evenly distributing the number of high and low chips in this manner maximizes the spreading quality of the PN code. During a single code period of the PN sequence, the chips in the sequence are generated one time in succession. The transmitter's digital hardware block 56 modulates digital data from the processor 54 onto the primary PN code by adjusting the starting point of the PN sequence at the beginning of each code period, as discussed below. By adjusting the starting point of the PN code, the digital hardware block 56 creates “code phase shifts” in the code, each of which represents a different data “symbol” identifying a unique combination of data from the processor. The maximum number of data bits identified by each data symbol depends on the length of the PN code and the size of the code phase shifts separating the data symbols. Since data symbols typically should be separated by phase shifts of at least two chips to allow adequate reception, a PN code comprising 2 M chips may support an alphabet of 2 M−1 symbols encoding M−1 bits of digital data. For example, a 64-chip PN code (M=6) may support up to 32 (2 5 ) symbols that encode up to 5 bits of binary data. In this manner, CCSK modulation allows for the transmission of several bits of digital data for each period of the spreading sequence, which reduces the duration of transmitted packets and which, in turn, improves the efficiency of devices in the wireless network.
[0026] Referring to FIG. 3, a suitable PN code may be generated with standard electronic components. One such code is the 63-chip code 75 of FIG. 3, which represents one of the maximal length sequences that may be generated using a standard 6-bit feedback shift register. The 63-chip sequence 75 ideally is generated at a code frequency of approximately 19.2 kHz, so each code period of the sequence has a total duration of approximately 52 μsec. Therefore, each chip has a duration of approximately 825 nsec, and the chip rate is approximately 1.2 Mchip/sec. Multiplying the RF carrier wave by this spreading sequence converts the carrier spectrum from an impulse at the carrier frequency in the ISM band to a sin(x)/x (sinc function) shape, where the first nulls of the sinc function are offset by approximately ±1.2 MHz from the carrier frequency. The fine structure of the spread spectrum carrier includes spectral lines at a spacing approximately 19.2 kHz.
[0027] Referring also to FIG. 4, four bits of digital data may be modulated onto the 63-chip PN code 75 for each code period. Since four digital bits may take on sixteen different values, the four bits are represented by sixteen different code phases of the PN code, each formed by starting the PN code at a corresponding one of the sixty-three chips (“16-CCSK” modulation). While any allocation of code phases at least two chips apart may be used to generate a sixteen symbol alphabet, one simple alphabet includes a first symbol (“symbol 0”) that begins with the first chip (“chip 0”) of the PN code 75 and fifteen other symbols (“symbol 1” through “symbol 15”) that each begin exactly two chips behind the preceding symbol. Since one symbol is transmitted for every period of the PN code, the data symbol rate equals the code frequency (19.2 kHz), and the digital data transmission rate is four times the code frequency (76.8 kbits/sec).
[0028] To recover 16-CCSK modulated data, a receiver must determine which of the sixteen PN code phases was used in the spreading process. The receiver 52 of FIG. 2 accomplishes this by correlating, in parallel, the received signal against sixteen locally generated copies of the PN sequence, where each copy has a code phase shift corresponding to one of the sixteen symbol values. At the end of each symbol period, the receiver determines the symbol value by determining which copy of the PN sequence produced a correlation peak. The symbol phases should be separated by at least two chips to minimize errors by avoiding correlation overlap. The data recovery process, including signal correlation, is described in more detail below.
[0029] As mentioned above, each transmitter may include a spectral enrichment block that further improves the spreading qualities of the transmitter. Spectral enrichment superimposes a relatively slow, repeating binary sequence, also having logic levels of ±1, on top of the primary PN sequence. The enrichment sequence may be, e.g., a 15-chip sequence that has a chip rate equal to one-half of the symbol rate (e.g., approximately 9600 kHz). Therefore, each chip in the enrichment sequence covers two periods of the primary PN sequence, and the sequence changes values only at symbol boundaries. Modulating the spectral enrichment signal over the modulated PN sequence can allow the transmitter to operate at higher power levels without violating FCC power regulations. Spectral enrichment is described in more detail in U.S. patent application Ser. No. 08/473,091, entitled “Direct Sequence Spread Spectrum System,” filed by Forrest F. Fulton on Jun. 6, 1995.
[0030] Referring now to FIG. 5, each packet 80 transmitted between the system controller 34 and one of the endpoint devices 32 in the wireless network 30 of FIG. 1 should have a known structure to ensure that it will be recognized and properly decoded by the intended recipient device. Therefore, each packet 80 will include a preamble 82 consisting of multiple repetitions of the primary PN sequence. The preamble 82 allows the receiver to recognize that a packet has been sent and to synchronize to the phase of the PN sequence used in generating the packet (i.e., the “transmission phase”). Increasing the length of the preamble increases the chances of accurately detecting each packet, but also increases the total duration of each packet and therefore decreases the overall efficiency of the network. Once detected, the incoming PN transmission phase serves as a reference phase for all subsequent data demodulation, as described in more detail below.
[0031] Following the preamble 82 is a 2-CCSK synchronization (“sync”) word 84 , which consists of multiple known symbols (each carrying one bit of binary data) that indicate to the receiver that data delivery is about to begin. The sync word 84 also allows the receiver to discard most erroneous packets not otherwise detected. Encoding the sync word 84 as 2-CCSK provides a slight gain in sensitivity over the 16-CCSK modulation used to encode the digital data that follows. The sync word 84 may consist of a Barker code encoded using the first two code phases (“symbol 0” and “symbol 1”) of the sixteen symbol alphabet described above.
[0032] Following the sync word 84 is a header 86 of known length that contains an address field indicating the address of the source of the packet. The address field also may indicate the address of the intended recipient of the packet. The header 86 also includes a length field indicating the length of the data payload to follow. The header 66 also may contain control bits.
[0033] Following the header is the data payload portion 88 of the packet 80 , which may include up to 255 symbols of 16-CCSK modulated data per byte in the length field of the header. Following the data payload portion 88 is FEC parity information 90 for use in detecting and correcting packet corruption.
[0034] Referring now to FIG. 6, the receiver 52 includes an antenna 100 coupled to a standard RF tuner 102 , which down converts the received signal from the RF carrier to the IF carrier and adjusts the power level of the signal, if necessary, to ensure that it falls within a range suitable for analog-to-digital (A/D) conversion. The down converted analog signal then is provided to an A/D converter 104 , which samples the signal at a sampling rate (F s ) eight times the chip rate of the PN spreading sequence. In other words, for a 63-bit PN sequence having a chip rate of 1.2 MHZ, the A/D converter 104 samples the incoming signal at a rate of approximately 9.6 MHZ, or eight samples per chip (8× over sampling). The A/D converter 104 performs a “fixed conversion” which allows the A/D converter 104 to output the sampled spread spectrum signal at a second intermediate carrier frequency lower than the sampling rate. Ideally, the second IF carrier frequency equals approximately one-quarter the sampling frequency (F s /4). Converting the incoming digital signal to F s /4 provides several advantages, such as 1) allowing the use of an AC-coupled filter 115 (or “DC block”) to eliminate DC offset introduced by the RF tuner 102 , the A/D converter 104 , and the AGC circuit 106 ; 2) allowing the use of implementation efficient bandpass correlators, as described below; and 3) allowing extraction of the in-phase and quadrature components through a de-interleaving process. The digital tuner 110 may down convert the digital signal to any other fractional frequency of the sampling frequency, provided that the upper end of the digital signal's bandwidth remains below F s /2 and the lower end of the bandwidth remains high enough to allow the AC-coupled filter 115 to remove unwanted DC offset. The A/D converter 104 provides its digital output to an automatic gain control (AGC) circuit 106 , which keeps the amplitude of the digital signal within an appropriate range, and to a power estimation block 108 , which calculates the total energy of the digital signal. The output of the power estimation block 108 is used by the receiver 52 to evaluate whether a packet has been received, as discussed below, and to provide information to an AGC algorithm performed by the processor.
[0035] The digital signal, centered at F s /4, is provided to a bank of eighty-four primary correlators 114 , some of which are used in each of the three stages (or “modes”) of the receiver's operation: search/qualification, acquisition, and demodulation. Each of the primary correlators 114 compares the incoming digital signal against a particular code phase of the PN sequence, a copy of which is provided to the primary correlator 114 by a PN sequence generator 116 . As described in more detail below, the primary correlator 114 correlates the incoming signal with the copy by multiplying the two signals to form a product signal. If the code phases are aligned, the product signal is a DC signal having a value of “1”. Each primary correlator 114 integrates its product signal over the symbol period to form a correlation output, which generally will have a high magnitude relative to noise if the signals are aligned and a low magnitude relative to noise otherwise. An implementation efficient bandpass correlator structure is described in detail below.
[0036] The digital signal, centered at F s /4, also is provided to four auxiliary correlators 118 , which are used to verify potential signal detections (“trips”) produced during the search/qualification mode, and to fine-tune the receiver to the frequency of the incoming signal during the acquisition mode. Each of the auxiliary correlators 118 should be able to receive a copy of the PN sequence at any one of the possible code phases and should be individually tunable over the desired frequency range discussed below. The auxiliary correlators 118 may use the implementation efficient bandpass correlator structure described below.
[0037] A post-correlator processing block 120 continuously monitors the outputs of the primary correlators 114 and identifies correlation peaks, each of which indicates that the code phase of the PN sequence in one of the primary correlators 114 may have matched the incoming signal during a symbol period. During the search/qualification mode, the processing block 120 produces a trip signal indicating when a correlation output may indicate a signal trip. The processing block 120 also includes a series of comparators which, during the demodulation mode, rank the correlation outputs during each symbol period according to magnitude. This information is used by the processor to demodulate the incoming data.
[0038] A correlator control logic block 122 controls operation of the correlators during the three modes of operation. The control logic block 122 includes a state machine that steps through the three operation modes and digital circuitry that supplies control signals to each of the correlators 114 and 118 , according to instructions from the processor (not shown in FIG. 6). A processor interface 124 allows the post-correlator processing block 120 and the control logic block 122 to provide information to the processor and allows the processor to provide instructions to the correlator control logic block 122 .
[0039] During the search/qualification mode, the receiver 52 must detect and recognize potential DSSS signals existing in the wireless network. During the acquisition mode, the receiver 52 must align to the transmission phase and frequency of the incoming signal. During demodulation, the receiver 52 must determine whether it is the intended recipient of the incoming signal and, if so, accurately demodulate the digital data contained in the signal.
[0040] As discussed above, the DSSS signals transmitted in the wireless network may consist of a carrier wave in the ISM band multiplied by a 63-chip PN sequence. To acquire one of these signals during the search and qualification mode, the receiver 52 must correlate the received signal with a local copy of the PN sequence that is almost perfectly aligned with the code phase of the original PN sequence. However, at minimal detectable signal levels the receiver 52 typically cannot recognize that a signal is present until after code phase alignment has occurred. Therefore, the process of alignment must proceed by trial and error.
[0041] Further complicating the search process are potential errors in the carrier frequency generated by the transmitter or the receiver's tuning frequency. In a typical wireless network the potential carrier error may be greater than ±50 kHz, so the receiver may need to search over a frequency range greater than 100 kHz centered at the nominal carrier frequency. In general, the receiver can detect signals only by searching an area defined by the PN sequence length and the carrier uncertainty by trial-and-error, and it must do so within a time defined by the packet preamble, leaving enough preamble time to align itself with the transmission phase of the incoming signal.
[0042] Typically, each primary special correlator 114 will respond with a maximum sensitivity loss of 4 dB to any signal within ±⅜ chip and ±5 kHz of its code phase and frequency settings. The measurement of a correlator's response will be available once per symbol period, as described in more detail below. Therefore, each primary correlator 114 can search an area of ¾ chip and 10 kHz during one symbol period. To ensure that the entire 63-chip range is searched during each symbol period and that the entire code/frequency range is searched in a reasonable time, eighty-four primary correlators 114 are required [(63 chips)÷(¾ chip per correlator)=84 correlators], each tuned to one of eighty-four search phases separated by ¾ chip.
[0043] The correlator control logic block 122 automates the search process. The control logic 122 initializes each of the primary correlators 114 to a corresponding one of the eighty-four possible ¾-chip search phases of the PN sequence and to the nominal carrier frequency, as commanded by the processor. The primary correlators 114 each include frequency adjustment elements, as described below. Each primary correlator 114 correlates the corresponding search phase of the PN sequence against the incoming digital signal for a symbol period, dumps its correlation output, and immediately begins correlating again against the digital signal over the next symbol period. The search frequency of each primary correlator 114 is increased by 10 kHz at the end of each symbol period until it reaches the upper end of the carrier uncertainty range and then is decreased by 10 kHz per symbol period until the lower end of the range is reached, and so on, until a signal is acquired.
[0044] The post-correlator processing block 120 monitors the correlation outputs at the end of each symbol period and generates a trip signal if any of the correlation outputs is sufficiently high. The processing block 120 does not generate a trip signal unless one of the correlation outputs, normalized to the output of the power estimator block 108 , exceeds a predetermined threshold. This threshold depends upon the characteristics of the network in which the receiver 52 is used, and factors such as the minimum detectable signal level and the false trip rate may be taken into account.
[0045] When the correlator control logic block 122 receives a trip signal, it commands one of the four auxiliary correlators 118 to qualify the trip while the primary correlators 114 continue searching. The control logic 122 sets the assigned auxiliary correlator to the frequency at which the trip occurred and instructs the PN sequence generator to provide the auxiliary correlator 118 with a copy of the PN sequence at the search phase associated with the trip. To qualify the trip, the auxiliary correlator correlates the incoming digital signal against the PN sequence at the selected search phase over successive symbol periods. The correlation over a given symbol period is a “success” if the correlation output of the auxiliary correlator 118 , normalized to the output of the power estimator block 108 , exceeds a predetermined threshold. The trip is qualified after three consecutive successful symbol periods. On the other hand, the auxiliary correlator 118 drops the trip and ends qualification after three consecutive unsuccessful correlating periods or after twelve symbol periods have passed without qualification. If no auxiliary correlators 118 are available when a trip signal occurs (i.e., if all four auxiliary correlators 118 are busy qualifying trips), the receiver queues the trip. When a trip signal is qualified, the primary correlators 114 stop searching and the receiver 52 enters the acquisition mode.
[0046] The acquisition mode consists of two phases: fine code search and fine frequency search. During fine code search, the receiver 52 sets each primary correlator 114 to the frequency of the qualified trip and sets each of the first sixteen primary correlators 114 to sixteen consecutive phases of the PN sequence separated by one sample. The eighth correlator correlates against the search phase of the qualified trip; the seven preceding correlators correlate against the seven phases, each separated by one sample, immediately preceding the search phase of the qualified trip; and the eight following correlators correlate against the eight phases, each separated by one sample, immediately following the search phase of the qualified trip. The sixteen correlators collect data for one symbol period, with each correlator's correlating period offset a sample behind the correlating period of the preceding correlator.
[0047] The outputs of the sixteen correlators undergo a special fine code correlation against an ideal relationship between code phase error and correlator response. This special correlation indicates which offset from the code phase of the qualified trip most closely correlates to the ideal response, which is considered over a range of ±4 samples from perfect code alignment. A normalized ideal response (R) at each sample offset is represented by the following equation:
R i =(1−64 i/ 504) 2 ,
[0048] where i is the offset in samples and −4≦i≦4. The correlation (C) of each sample offset against the ideal response then is determined by the following equation:
C j =ΣR i ·O l+j+7 ,
[0049] where O k is the output of the k th correlator (0≦k<16), where i and j represent the offset in samples (−4≦i,j≦4). For j=−4 and i=−4, “i+j” is less than zero, so the special correlation value at these offset values is disregarded. The best-fit code phase is the one for which the corresponding correlation value (C j ) is largest (“code phase zero” or “data phase zero”). The receiver 52 continues to qualify any outstanding search trips during fine code search but terminates trip qualification when the fine code search stage is successful.
[0050] In the fine frequency search phase, which begins after the fine code search is successful, the four auxiliary correlators 118 are used to find the peak of the frequency response to the incoming signal. Each of the auxiliary correlators 118 is set to code phase zero, as determined in the fine code search phase, and to one of several frequencies near the frequency of the qualified trip. Each auxiliary correlator 118 then provides an output representing a point on a frequency response curve, the peak of which represents the signal frequency and may be calculated by the processor.
[0051] The receiver 52 also incorporates false peak rejection to ensure that it does not lose valid data packets after detecting and qualifying “false” peaks that may occur at code phases and/or frequencies other than the actual phases and frequencies of the true signals. The processor will recognize a false peak when the signal-to-noise (S/N) ratio of the tripping signal does not improve beyond −13 dB during the fine code and fine frequency search phases. To reject false peaks and to avoid subsequent trips on false peaks from the same signal, the processor drops any signal for which the S/N ratio has not improved by 12 dB after the fine code and fine frequency search phases and sets the trip threshold 6 dB higher than normal during the subsequent search process. Increasing the threshold in this manner should allow the receiver 52 to detect the true peak of a strong signal while ignoring the false peaks.
[0052] When the fine code and fine frequency search phases are complete, the receiver 52 begins watching for the sync word. Because the sync word is encoded with 2-CCSK modulation, as described above, the correlator control logic 122 assigns only two primary correlators 114 to monitor the incoming signal for the sync word. The two assigned correlators are the correlator associated with code phase zero, as determined in the fine code search phase, and the correlator immediately following it. The two correlators then correlate the incoming signal against the corresponding code phase over the same correlation period. The correlation outputs of the two correlators are provided to the processor, which assigns each symbol in the sync word a soft value S i according to the equation:
S l =( A l −B i )/( A i +B i ),
[0053] where A l and B i represent the correlation outputs of the two correlators at each symbol period. The processor stores up to thirteen soft values and, after each symbol period, forms a correlation sum (C) according to the equation:
C=ΣS i ·β i ,
[0054] where the sum runs from i=0 to 12 and where β i represents the actual value of the i th bit of the synch word, with logic levels of ±1. The signal is declared synchronized when the correlation sum is greater than some predetermined threshold.
[0055] During the demodulation mode, sixteen of the primary correlators 114 correlate the incoming digital signal to the sixteen different code phases defining the 16-CCSK symbol alphabet, with the first correlator corresponding to code phase zero, as determined during the fine code search phase, and the following correlators successively corresponding to the other fifteen code phases. All sixteen correlators use the same correlation period in the demodulation mode. At the end of each symbol period, the post-correlator processor block 120 determines which correlators have the highest correlation outputs. The processor assigns a symbol value to the symbol period based on which correlator produces the highest correlation output. The processor may be programmed so that it does not assign a symbol value (i.e., it issues an “erasure”) if the ratio of the highest correlation output to the second highest correlation output does not exceed some predetermined threshold.
[0056] During demodulation, the receiver also tracks the code phase of the incoming signal. Code phase tracking ensures that the receiver does not lose alignment with the signal as a result of clock drift that may affect the output of the PN sequence generator 116 . To track the code phase, the correlator control logic 122 assigns thirty-two additional primary correlators 114 , half of which provide “early” correlation values and the other half of which provide “late” correlation values. Each “early” correlator is set to a code phase that is between one and four samples ahead of the code phase associated with one of the main demodulation correlators (“on-phase” correlators) discussed above. Each “late” correlator is set to a code phase that is between one and four samples behind the code phase associated with one of the on-phase correlators. The receiver 52 uses the correlation outputs of the early and late correlators associated with the on-phase correlator aligning to the incoming signal during each symbol period to calculate a code phase error (R), according to the equation:
R =( E−L )/ O,
[0057] where E and L are the outputs of the early and late correlators and O is the output of the on-phase correlator. The code phase error may be used to update the clocking rate of the PN sequence generator 116 when the error is, e.g., greater than {fraction (1/16)} chip.
[0058] Referring also to FIGS. 7A and 7B, the receiver begins operation upon startup by initializing the automatic gain control circuit (step 300 ). The receiver then enters the search mode (step 302 ) and continuously searches for a DSSS signal, constantly monitoring and adjusting the AGC circuit (step 304 ), until a trip signal occurs (step 306 ). When a trip signal occurs, the receiver determines whether all of the auxiliary correlators are busy (step 308 ). If so, the receiver queues the trip signal (step 310 ) and continues searching (step 302 ); otherwise, the receiver assigns an auxiliary correlator to qualify the trip (step 312 ). The receiver then monitors the qualification process to determine whether the trip signal is qualified or rejected within the allotted period of time (steps 314 and 318 ). If neither qualification nor rejection occurs within twelve symbol periods, the receiver aborts the qualification process for that trip signal (step 316 ) and continues searching for DSSS signals (step 302 ). The receiver also continues searching if the trip signal is disqualified (step 318 ). If, on the other hand, the auxiliary correlator qualifies the trip signal, the receiver enters the acquisition mode.
[0059] In the acquisition mode, the receiver first assigns several primary correlators to carry out the fine code search (step 320 ). The receiver then monitors the assigned correlators to determine whether the code phase is successfully acquired (step 322 ). If not, the receiver returns to the search mode and resumes its search for DSSS signals (step 302 ); otherwise, the receiver instructs the auxiliary correlators to enter the fine frequency search phase (step 324 ). The receiver then monitors the four general correlators to determine whether the fine frequency search leads to successful acquisition of the frequency offset (step 326 ). If not, the receiver returns to the search mode and resumes searching (step 302 ); otherwise, the receiver prepares for sync word detection (step 328 ). If the expected sync word is not detected within the appropriate time limit, the sync word detection process times out (step 330 ) and is aborted (step 316 ), and the receiver again begins searching for DSSS signals (step 302 ). If the sync word is detected, the receiver enters the demodulation mode (step 332 ). In the demodulation mode, the receiver continuously tracks the code phase of the incoming data signal to prevent drift in alignment (step 334 ). If too many erasures occur during demodulation (step 333 ), the demodulation process is aborted (step 316 ) and the receiver again searches for DSSS signals (step 302 ). Otherwise, the receiver continues to demodulate data until the end of the transmitted packet (step 336 ). When the end of the packet is reached, the receiver leaves the demodulation mode, reenters the search mode, and again begins searching for DSSS signals (step 302 ).
[0060] Referring now to FIG. 8A, each bandpass correlator (primary and auxiliary) in the receiver may utilize an implementation efficient (IE) correlator structure 130 . As discussed above, the incoming digital signal 131 should enter the correlator at a carrier frequency equal to approximately one-quarter the digital sampling rate (F s /4). The IE correlator structure provides approximate quadrature processing and frequency adjustment in a unified block that requires few and inexpensive components. The structure includes a digital multiplier 132 followed by an accumulation loop 134 having a primary summer 136 and two delay elements 138 and 140 , both of which may be single sample delay registers. The output 141 of the second delay register 140 feeds back to the primary summer 136 and is subtracted from the product output 135 of the multiplier 132 . The output 139 of the first delay register 138 feeds directly into the second delay register 140 . Output 139 also may be provided to a frequency adjustment element 145 that allows the processor to adjust the resonant frequency of the accumulation loop 134 . Within the frequency adjustment element 145 , the output 139 of the first delay register 138 is scaled by a scaling element 144 , fed back to a secondary summer 142 , and added to the output 137 of the primary summer 136 . The correlator structure 130 may be implemented in standard, off-the-shelf components, but it is particularly suited for implementation in an application specific integrated circuit (ASIC).
[0061] In operation, the incoming digital signal 131 and a local copy of the PN sequence 133 are provided as inputs to the multiplier 132 . If the two are in code phase alignment, the code product always equals “1” and the output 135 of the multiplier is simply the F s /4 carrier wave. Because the loop delay is two samples, the output 141 of the second delay register 140 is approximately 180° out-of-phase with the multiplier output 135 and therefore reinforces the multiplier output 135 in the primary summer 136 during the subtraction operation. The input 143 and the output 149 of the first delay register 138 differ by one sample time and therefore are approximately 90° out-of-phase, so they may be taken as the in-phase and quadrature components, respectively, of the F s /4 carrier wave. At the end of the accumulation time (one correlation period), the in-phase and quadrature outputs are taken and the delay registers 138 and 140 both are set to zero to re-initialize the accumulation loop 134 . The final output 151 is the sum of the squares of the in-phase and quadrature components at the end of each correlation period, as provided by squaring circuits 146 and 148 and adder 150 .
[0062] Instead of a single-sample, register 140 may delay output 139 by multiple samples, so that the phase offset between output 135 and output 141 is a multiple of 180°. For example, a three sample delay in register 140 leaves output 141 360° out-of-phase with product output 135 . In this case, primary summer 136 will add output 141 to product output 135 to form an accumulation output.
[0063] The frequency adjustment element 145 includes a scaling element 144 , the scaling factor (K) of which is variable to allow for frequency adjustment within the correlator's accumulation loop 134 . The scaling factor K has a value equal to 2·cos(Ω 0 ), where Ω 0 represents 2π times the ratio of the desired resonant frequency of the accumulation loop 134 to the sampling rate (F s ) of the A/D converter 104 (the absolute value of K typically will be much less than one). The value of the scaling factor may be selected by the processor and stored in a programmable storage element 144 b such as a register. A multiplication element 144 a applies the scaling factor to the output 139 of the first delay register 138 , and the resulting signal is added by the secondary summer 142 to the output 137 of the primary summer 136 . When the scaling factor has a value of zero, the secondary summer 142 has no effect on the correlator structure. However, when the scaling factor is slightly above or below zero, the effective delay in the accumulation loop 134 is slightly greater than or less than two samples, so the loop response is centered at a frequency slightly below or slightly above F s /4. Since the delay between the output 139 of delay element 138 and the output 141 of delay element 140 always remains at one sample, adjusting the scaling factor to a value other than zero introduces a small quadrature error at frequencies offset from F s /4. At small frequency offsets, the quadrature error is insignificant.
[0064] Referring to FIG. 8B, a quadrature error correction element 160 may be added to the correlator structure 130 to eliminate the quadrature error introduced by the scaling element 144 . The correction element 160 includes two multiplication elements 162 and 164 , which multiply the output 139 of the accumulation loop 134 with signals equal to cos(Ω 0 ) and sin(Ω 0 ). The output 165 of multiplication element 164 represents the corrected quadrature component of the accumulation output and is provided to squaring circuit 148 . Summer 166 produces the corrected in-phase component of the accumulation output by subtracting the output 163 of multiplication element 162 from the output 143 of secondary summer 142 . The corrected in-phase component is provided to squaring circuit 146 .
[0065] Referring also to FIG. 9, when a binary PN sequence serves as the spreading signal, the digital multiplier 132 may be a simple sign inverter realized, e.g., as a digital multiplexer 155 receiving the incoming digital signal 131 and an inverted version 131 ′ of this signal as inputs and having a local copy of the PN sequence 133 as its control signal. The non-inverted signal 131 ′ is selected by the multiplexer 155 when the PN sequence 133 is high, and the inverted signal 131 ′ is selected when the PN sequence 133 is low. When the incoming signal 131 and the PN sequence 133 are aligned, the PN sequence cancels the spreading signal from the incoming signal 131 and only the F s /4 carrier wave exits the multiplexer 155 .
[0066] Other embodiments are within the scope of the following claims. | A digitally sampled spread spectrum signal is received, despread, and accumulated at a center frequency lower than the sampling rate and higher than zero. | Summarize the key points of the given patent document. | [
"RELATED APPLICATIONS [0001] This application is related to the following co-pending applications, all filed on the same day and naming the same inventors as this application: “Processing a Spread Spectrum Signal in a Frequency Adjustable System”;",
"“Bandpass Correlation of a Spread Spectrum Signal”;",
"“Acquiring a Spread Spectrum Signal”;",
"and “Receiving a Spread Spectrum Signal.”",
"BACKGROUND OF THE INVENTION [0002] The invention relates to processing a spread spectrum signal.",
"[0003] In wireless systems, information typically is transmitted by modulating the information onto carrier waves having frequencies that lie within preassigned frequency bands.",
"Radio frequency (RF) receivers demodulate the carrier waves to recover the transmitted information.",
"[0004] Spread spectrum communication systems spread transmitted signals over bandwidths much larger than those actually required to transmit the information.",
"Spreading a signal over a wide spectrum has several advantages, including reducing the effects of narrow band noise on the signal and, in many situations, providing increased protection against interception by unwanted third parties.",
"In a direct sequence spread spectrum (DSSS) system, the bandwidth of a transmitted signal is increased by modulating the signal onto a known pseudo-noise (PN) signal before modulating onto the carrier wave.",
"The PN signal typically is a digital signal having an approximately equal number of high and low bits (or “chips”), which maximizes the spectrum over which the signal is spread.",
"A typical implementation of a DSSS receiver recovers the transmitted information by demodulating the carrier wave and then multiplying the resulting signal with a local replica of the PN signal to eliminate the PN signal.",
"The DSSS technique offers heightened security because the receiver must know the PN sequence used in the transmission to recover the transmitted information efficiently.",
"Other spread spectrum techniques include frequency hopped spread spectrum (FHSS).",
"SUMMARY OF THE INVENTION [0005] In one aspect, the invention features processing a spread spectrum signal digitally sampled at a selected sampling rate.",
"The digitally sampled signal is received and despread at a center frequency lower than the sampling rate and higher than zero, and is accumulated at the center frequency.",
"[0006] Embodiments of the invention may include one or more of the following features.",
"The center frequency may be limited to no greater than approximately one-half of the sampling rate, and it may be set to equal approximately one-quarter of the sampling rate.",
"A DC filter may be used to filter any DC offset from the digitally sampled spread spectrum signal.",
"The center frequency may be selected SO that no data embedded in the spread spectrum signal is blocked by the DC filter.",
"The spread spectrum signal may include a pseudo-noise (PN) spreading sequence, and the reference signal may contain the PN spreading sequence.",
"[0007] Advantages of the invention may include one or more of the following.",
"A spread spectrum signal may be processed without demodulating the signal to DC until the processing is complete.",
"An AC-coupled filter or other DC block may be used to eliminate DC offset from the spread spectrum signal before it is processed.",
"A direct sequence spread spectrum signal may be processed using a correlator with an implementation efficient structure, which will lower the cost of receivers in which the invention is used and improve the efficiency of such receivers.",
"[0008] Other advantages of the invention will become apparent from the following description and from the claims.",
"BRIEF DESCRIPTION OF THE DRAWINGS [0009] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the general description above and the detailed description below, serve to explain the principles and advantages of the invention.",
"[0010] [0010 ]FIG. 1 is a block diagram of a wireless local area network (LAN).",
"[0011] [0011 ]FIG. 2 is a block diagram of a transceiver for use in a wireless Network such as that shown in FIG. 1. [0012] [0012 ]FIG. 3 is waveform illustrating one period of a 63-chip PN sequence.",
"[0013] [0013 ]FIG. 4 is chart showing the code phases of a possible 16-CCSK alphabet generated from a 63-chip PN sequence.",
"[0014] [0014 ]FIG. 5 is a diagram showing the components of an information packet transmitted in a spread spectrum communication system using CCSK modulation.",
"[0015] [0015 ]FIG. 6 is a block diagram of a receiver for use in a spread spectrum communication system.",
"[0016] [0016 ]FIGS. 7A and 7B are flow diagrams of the operation of the receiver of FIG. 6 during search, acquisition, and demodulation of spread spectrum signals.",
"[0017] [0017 ]FIGS. 8A and 8B are block diagrams of implementation efficient correlators for use in recovering data from spread spectrum signals.",
"[0018] [0018 ]FIG. 9 is a schematic diagram of a sign inverter for use in the correlator of FIG. 8 in recovering data modulated onto direct sequence spread spectrum signals using cyclic code shift keying (CCSK) modulation.",
"DESCRIPTION OF THE PREFERRED EMBODIMENTS [0019] Referring to FIG. 1, spread spectrum technology is particularly suited for use in a wireless network 30 in which many devices (e.g., radios) transmit different streams of information within a relatively small geographic area.",
"The wireless network 30 may be used in remote monitoring applications, e.g., by large utility companies to monitor resource consumption remotely.",
"A network 30 used in such a manner typically consists of a large number of endpoint devices 32 , such as devices that record resource consumption at utility meters (e.g., electricity meters) located at business and residential structures throughout a metropolitan area.",
"The endpoint devices 32 gather information and, using internal wireless radio transceivers (not shown in the figure), periodically transmit the information as digital data packets through a hierarchical network to a system controller 34 .",
"System controller 34 typically includes a network server computer (not shown in the figure) that may distribute the information to clients 36 on a computer network 38 .",
"In larger metropolitan areas, endpoint devices 32 in the wireless network 30 may be organized into “cells”",
"40 , which may be divided into “microcells”",
"42 .",
"Typically, microcells 42 cover relatively small geographic areas of similar size or containing a similar number of endpoint devices 32 .",
"Each cell 40 is governed by a cell master 44 , which oversees operation of the endpoint devices 32 within the cell 40 and relays information between the system controller 34 and the endpoint devices 32 in the cell 40 .",
"Likewise, each microcell 42 is governed by a microcell controller 46 , which supervises the operation of all endpoint devices 32 in the microcell 42 and which relays information between the corresponding cell master 44 and the endpoint devices 32 in the microcell 42 .",
"[0020] The wireless network 30 should include as few microcell controllers 46 as possible since each controller 46 adds to the total cost of installing and administering the network 30 .",
"The number of microcell controllers 46 required in a given geographical area depends upon the minimum signal strength (“sensitivity”) at which each controller 46 can recover information contained in transmissions from the endpoint devices 32 in the corresponding microcell 42 .",
"The cost of the wireless network 30 may be reduced and its dynamic capabilities may be expanded if the wireless radios used in the communicating devices (e.g., system controller 34 , cell masters 44 , microcell controllers 46 , and endpoint devices 32 ) in the network 30 were to include more efficient components than those currently available.",
"[0021] The invention is suited for use in a wireless network such as that shown in FIG. 1 and in direct sequence spread spectrum (DSSS) systems in which cyclic code shift keying (CCSK) is used to modulate digital data onto digital pseudo-noise (PN) spreading sequences.",
"CCSK is a modulation technique in which circular phase shifts of a PN sequence are used to represent the possible constellation (or data) symbols.",
"For example, a 63-chip PN sequence could support up to 63 different data symbols, each of which would be 63-chips in length.",
"An M-CCSK constellation (or alphabet) is a group of M CCSK data symbols, each representing a unique combination of binary data bits, where M is an integer greater than one.",
"Spread spectrum communication systems using CCSK and related data modulation techniques are described in U.S. Pat. No. 4,707,839, issued to Andren et al.",
", on Nov. 17, 1987, and U.S. Pat. No. 4,730,340, issued to Frazier, Jr., et.",
"al, on Mar. 8, 1988, both of which are incorporated herein by reference.",
"The invention will be described in the context of a DSSS system using CCSK data modulation, but the invention is not limited to use in such a system.",
"[0022] Referring also to FIG. 2, each radio in the system controller 34 , cell masters 44 , microcell controllers 46 , and endpoint devices 32 of the DSSS wireless network 30 of FIG. 1 includes a transmitter 50 and a receiver 52 equipped to send and receive, respectively, spread spectrum signals carrying information encoded onto a PN sequence with CCSK modulation.",
"In the transmitter 50 , data to be transmitted is generated by a computing device, such as a microprocessor 54 .",
"A digital hardware block 56 receives the data, along with instructions for processing it, from the processor 54 and modulates the data onto a predetermined PN sequence to form a spread spectrum signal.",
"An RF hardware block 58 then modulates the spread spectrum signal onto an RF carrier wave (e.g., a wave in the ISM band ranging from 902 MHZ to 928 MHZ), the frequency of which is determined by frequency synthesizer 60 , and transmits the combined signal over a wireless transmission channel 62 .",
"The transmitter 50 also may include a spectral enrichment block 64 , which further improves the transmitter's spreading qualities by modulating an additional PN sequence over the CCSK modulated primary PN sequence, as discussed below.",
"[0023] The transmitted RF signal is received by the receiver 52 and may be down converted to an intermediate frequency (IF) by an RF hardware block 66 controlled by a local oscillator (LO) 68 .",
"The intermediate frequency is selected according to the following equation: IF=F s ·( N± ¼), [0024] where F s is the sampling rate of an A/D converter (discussed below) and N is an integer.",
"A digital hardware block 70 in the receiver 52 samples the IF signal and converts the samples to digital representation.",
"The digital hardware block 70 then demodulates the spread spectrum signal to recover the encoded digital data.",
"A processor 72 in the receiver controls the operation of the digital hardware block 70 and uses the recovered data as specified by firmware and software associated with the processor 72 .",
"Within each device in the wireless network 30 , a single processor may be used to control both the transmitter 50 and the receiver 52 .",
"[0025] The primary PN sequence (or “code”) used to create the spread spectrum signal consists of a predetermined number of repeating binary code bits (or “chips”), approximately half of which have a binary value of “1”",
"and the rest of which have a binary value of “−1.”",
"Evenly distributing the number of high and low chips in this manner maximizes the spreading quality of the PN code.",
"During a single code period of the PN sequence, the chips in the sequence are generated one time in succession.",
"The transmitter's digital hardware block 56 modulates digital data from the processor 54 onto the primary PN code by adjusting the starting point of the PN sequence at the beginning of each code period, as discussed below.",
"By adjusting the starting point of the PN code, the digital hardware block 56 creates “code phase shifts”",
"in the code, each of which represents a different data “symbol”",
"identifying a unique combination of data from the processor.",
"The maximum number of data bits identified by each data symbol depends on the length of the PN code and the size of the code phase shifts separating the data symbols.",
"Since data symbols typically should be separated by phase shifts of at least two chips to allow adequate reception, a PN code comprising 2 M chips may support an alphabet of 2 M−1 symbols encoding M−1 bits of digital data.",
"For example, a 64-chip PN code (M=6) may support up to 32 (2 5 ) symbols that encode up to 5 bits of binary data.",
"In this manner, CCSK modulation allows for the transmission of several bits of digital data for each period of the spreading sequence, which reduces the duration of transmitted packets and which, in turn, improves the efficiency of devices in the wireless network.",
"[0026] Referring to FIG. 3, a suitable PN code may be generated with standard electronic components.",
"One such code is the 63-chip code 75 of FIG. 3, which represents one of the maximal length sequences that may be generated using a standard 6-bit feedback shift register.",
"The 63-chip sequence 75 ideally is generated at a code frequency of approximately 19.2 kHz, so each code period of the sequence has a total duration of approximately 52 μsec.",
"Therefore, each chip has a duration of approximately 825 nsec, and the chip rate is approximately 1.2 Mchip/sec.",
"Multiplying the RF carrier wave by this spreading sequence converts the carrier spectrum from an impulse at the carrier frequency in the ISM band to a sin(x)/x (sinc function) shape, where the first nulls of the sinc function are offset by approximately ±1.2 MHz from the carrier frequency.",
"The fine structure of the spread spectrum carrier includes spectral lines at a spacing approximately 19.2 kHz.",
"[0027] Referring also to FIG. 4, four bits of digital data may be modulated onto the 63-chip PN code 75 for each code period.",
"Since four digital bits may take on sixteen different values, the four bits are represented by sixteen different code phases of the PN code, each formed by starting the PN code at a corresponding one of the sixty-three chips (“16-CCSK”",
"modulation).",
"While any allocation of code phases at least two chips apart may be used to generate a sixteen symbol alphabet, one simple alphabet includes a first symbol (“symbol 0”) that begins with the first chip (“chip 0”) of the PN code 75 and fifteen other symbols (“symbol 1”",
"through “symbol 15”) that each begin exactly two chips behind the preceding symbol.",
"Since one symbol is transmitted for every period of the PN code, the data symbol rate equals the code frequency (19.2 kHz), and the digital data transmission rate is four times the code frequency (76.8 kbits/sec).",
"[0028] To recover 16-CCSK modulated data, a receiver must determine which of the sixteen PN code phases was used in the spreading process.",
"The receiver 52 of FIG. 2 accomplishes this by correlating, in parallel, the received signal against sixteen locally generated copies of the PN sequence, where each copy has a code phase shift corresponding to one of the sixteen symbol values.",
"At the end of each symbol period, the receiver determines the symbol value by determining which copy of the PN sequence produced a correlation peak.",
"The symbol phases should be separated by at least two chips to minimize errors by avoiding correlation overlap.",
"The data recovery process, including signal correlation, is described in more detail below.",
"[0029] As mentioned above, each transmitter may include a spectral enrichment block that further improves the spreading qualities of the transmitter.",
"Spectral enrichment superimposes a relatively slow, repeating binary sequence, also having logic levels of ±1, on top of the primary PN sequence.",
"The enrichment sequence may be, e.g., a 15-chip sequence that has a chip rate equal to one-half of the symbol rate (e.g., approximately 9600 kHz).",
"Therefore, each chip in the enrichment sequence covers two periods of the primary PN sequence, and the sequence changes values only at symbol boundaries.",
"Modulating the spectral enrichment signal over the modulated PN sequence can allow the transmitter to operate at higher power levels without violating FCC power regulations.",
"Spectral enrichment is described in more detail in U.S. patent application Ser.",
"No. 08/473,091, entitled “Direct Sequence Spread Spectrum System,” filed by Forrest F. Fulton on Jun. 6, 1995.",
"[0030] Referring now to FIG. 5, each packet 80 transmitted between the system controller 34 and one of the endpoint devices 32 in the wireless network 30 of FIG. 1 should have a known structure to ensure that it will be recognized and properly decoded by the intended recipient device.",
"Therefore, each packet 80 will include a preamble 82 consisting of multiple repetitions of the primary PN sequence.",
"The preamble 82 allows the receiver to recognize that a packet has been sent and to synchronize to the phase of the PN sequence used in generating the packet (i.e., the “transmission phase”).",
"Increasing the length of the preamble increases the chances of accurately detecting each packet, but also increases the total duration of each packet and therefore decreases the overall efficiency of the network.",
"Once detected, the incoming PN transmission phase serves as a reference phase for all subsequent data demodulation, as described in more detail below.",
"[0031] Following the preamble 82 is a 2-CCSK synchronization (“sync”) word 84 , which consists of multiple known symbols (each carrying one bit of binary data) that indicate to the receiver that data delivery is about to begin.",
"The sync word 84 also allows the receiver to discard most erroneous packets not otherwise detected.",
"Encoding the sync word 84 as 2-CCSK provides a slight gain in sensitivity over the 16-CCSK modulation used to encode the digital data that follows.",
"The sync word 84 may consist of a Barker code encoded using the first two code phases (“symbol 0”",
"and “symbol 1”) of the sixteen symbol alphabet described above.",
"[0032] Following the sync word 84 is a header 86 of known length that contains an address field indicating the address of the source of the packet.",
"The address field also may indicate the address of the intended recipient of the packet.",
"The header 86 also includes a length field indicating the length of the data payload to follow.",
"The header 66 also may contain control bits.",
"[0033] Following the header is the data payload portion 88 of the packet 80 , which may include up to 255 symbols of 16-CCSK modulated data per byte in the length field of the header.",
"Following the data payload portion 88 is FEC parity information 90 for use in detecting and correcting packet corruption.",
"[0034] Referring now to FIG. 6, the receiver 52 includes an antenna 100 coupled to a standard RF tuner 102 , which down converts the received signal from the RF carrier to the IF carrier and adjusts the power level of the signal, if necessary, to ensure that it falls within a range suitable for analog-to-digital (A/D) conversion.",
"The down converted analog signal then is provided to an A/D converter 104 , which samples the signal at a sampling rate (F s ) eight times the chip rate of the PN spreading sequence.",
"In other words, for a 63-bit PN sequence having a chip rate of 1.2 MHZ, the A/D converter 104 samples the incoming signal at a rate of approximately 9.6 MHZ, or eight samples per chip (8× over sampling).",
"The A/D converter 104 performs a “fixed conversion”",
"which allows the A/D converter 104 to output the sampled spread spectrum signal at a second intermediate carrier frequency lower than the sampling rate.",
"Ideally, the second IF carrier frequency equals approximately one-quarter the sampling frequency (F s /4).",
"Converting the incoming digital signal to F s /4 provides several advantages, such as 1) allowing the use of an AC-coupled filter 115 (or “DC block”) to eliminate DC offset introduced by the RF tuner 102 , the A/D converter 104 , and the AGC circuit 106 ;",
"2) allowing the use of implementation efficient bandpass correlators, as described below;",
"and 3) allowing extraction of the in-phase and quadrature components through a de-interleaving process.",
"The digital tuner 110 may down convert the digital signal to any other fractional frequency of the sampling frequency, provided that the upper end of the digital signal's bandwidth remains below F s /2 and the lower end of the bandwidth remains high enough to allow the AC-coupled filter 115 to remove unwanted DC offset.",
"The A/D converter 104 provides its digital output to an automatic gain control (AGC) circuit 106 , which keeps the amplitude of the digital signal within an appropriate range, and to a power estimation block 108 , which calculates the total energy of the digital signal.",
"The output of the power estimation block 108 is used by the receiver 52 to evaluate whether a packet has been received, as discussed below, and to provide information to an AGC algorithm performed by the processor.",
"[0035] The digital signal, centered at F s /4, is provided to a bank of eighty-four primary correlators 114 , some of which are used in each of the three stages (or “modes”) of the receiver's operation: search/qualification, acquisition, and demodulation.",
"Each of the primary correlators 114 compares the incoming digital signal against a particular code phase of the PN sequence, a copy of which is provided to the primary correlator 114 by a PN sequence generator 116 .",
"As described in more detail below, the primary correlator 114 correlates the incoming signal with the copy by multiplying the two signals to form a product signal.",
"If the code phases are aligned, the product signal is a DC signal having a value of “1.”",
"Each primary correlator 114 integrates its product signal over the symbol period to form a correlation output, which generally will have a high magnitude relative to noise if the signals are aligned and a low magnitude relative to noise otherwise.",
"An implementation efficient bandpass correlator structure is described in detail below.",
"[0036] The digital signal, centered at F s /4, also is provided to four auxiliary correlators 118 , which are used to verify potential signal detections (“trips”) produced during the search/qualification mode, and to fine-tune the receiver to the frequency of the incoming signal during the acquisition mode.",
"Each of the auxiliary correlators 118 should be able to receive a copy of the PN sequence at any one of the possible code phases and should be individually tunable over the desired frequency range discussed below.",
"The auxiliary correlators 118 may use the implementation efficient bandpass correlator structure described below.",
"[0037] A post-correlator processing block 120 continuously monitors the outputs of the primary correlators 114 and identifies correlation peaks, each of which indicates that the code phase of the PN sequence in one of the primary correlators 114 may have matched the incoming signal during a symbol period.",
"During the search/qualification mode, the processing block 120 produces a trip signal indicating when a correlation output may indicate a signal trip.",
"The processing block 120 also includes a series of comparators which, during the demodulation mode, rank the correlation outputs during each symbol period according to magnitude.",
"This information is used by the processor to demodulate the incoming data.",
"[0038] A correlator control logic block 122 controls operation of the correlators during the three modes of operation.",
"The control logic block 122 includes a state machine that steps through the three operation modes and digital circuitry that supplies control signals to each of the correlators 114 and 118 , according to instructions from the processor (not shown in FIG. 6).",
"A processor interface 124 allows the post-correlator processing block 120 and the control logic block 122 to provide information to the processor and allows the processor to provide instructions to the correlator control logic block 122 .",
"[0039] During the search/qualification mode, the receiver 52 must detect and recognize potential DSSS signals existing in the wireless network.",
"During the acquisition mode, the receiver 52 must align to the transmission phase and frequency of the incoming signal.",
"During demodulation, the receiver 52 must determine whether it is the intended recipient of the incoming signal and, if so, accurately demodulate the digital data contained in the signal.",
"[0040] As discussed above, the DSSS signals transmitted in the wireless network may consist of a carrier wave in the ISM band multiplied by a 63-chip PN sequence.",
"To acquire one of these signals during the search and qualification mode, the receiver 52 must correlate the received signal with a local copy of the PN sequence that is almost perfectly aligned with the code phase of the original PN sequence.",
"However, at minimal detectable signal levels the receiver 52 typically cannot recognize that a signal is present until after code phase alignment has occurred.",
"Therefore, the process of alignment must proceed by trial and error.",
"[0041] Further complicating the search process are potential errors in the carrier frequency generated by the transmitter or the receiver's tuning frequency.",
"In a typical wireless network the potential carrier error may be greater than ±50 kHz, so the receiver may need to search over a frequency range greater than 100 kHz centered at the nominal carrier frequency.",
"In general, the receiver can detect signals only by searching an area defined by the PN sequence length and the carrier uncertainty by trial-and-error, and it must do so within a time defined by the packet preamble, leaving enough preamble time to align itself with the transmission phase of the incoming signal.",
"[0042] Typically, each primary special correlator 114 will respond with a maximum sensitivity loss of 4 dB to any signal within ±⅜ chip and ±5 kHz of its code phase and frequency settings.",
"The measurement of a correlator's response will be available once per symbol period, as described in more detail below.",
"Therefore, each primary correlator 114 can search an area of ¾ chip and 10 kHz during one symbol period.",
"To ensure that the entire 63-chip range is searched during each symbol period and that the entire code/frequency range is searched in a reasonable time, eighty-four primary correlators 114 are required [(63 chips)÷(¾ chip per correlator)=84 correlators], each tuned to one of eighty-four search phases separated by ¾ chip.",
"[0043] The correlator control logic block 122 automates the search process.",
"The control logic 122 initializes each of the primary correlators 114 to a corresponding one of the eighty-four possible ¾-chip search phases of the PN sequence and to the nominal carrier frequency, as commanded by the processor.",
"The primary correlators 114 each include frequency adjustment elements, as described below.",
"Each primary correlator 114 correlates the corresponding search phase of the PN sequence against the incoming digital signal for a symbol period, dumps its correlation output, and immediately begins correlating again against the digital signal over the next symbol period.",
"The search frequency of each primary correlator 114 is increased by 10 kHz at the end of each symbol period until it reaches the upper end of the carrier uncertainty range and then is decreased by 10 kHz per symbol period until the lower end of the range is reached, and so on, until a signal is acquired.",
"[0044] The post-correlator processing block 120 monitors the correlation outputs at the end of each symbol period and generates a trip signal if any of the correlation outputs is sufficiently high.",
"The processing block 120 does not generate a trip signal unless one of the correlation outputs, normalized to the output of the power estimator block 108 , exceeds a predetermined threshold.",
"This threshold depends upon the characteristics of the network in which the receiver 52 is used, and factors such as the minimum detectable signal level and the false trip rate may be taken into account.",
"[0045] When the correlator control logic block 122 receives a trip signal, it commands one of the four auxiliary correlators 118 to qualify the trip while the primary correlators 114 continue searching.",
"The control logic 122 sets the assigned auxiliary correlator to the frequency at which the trip occurred and instructs the PN sequence generator to provide the auxiliary correlator 118 with a copy of the PN sequence at the search phase associated with the trip.",
"To qualify the trip, the auxiliary correlator correlates the incoming digital signal against the PN sequence at the selected search phase over successive symbol periods.",
"The correlation over a given symbol period is a “success”",
"if the correlation output of the auxiliary correlator 118 , normalized to the output of the power estimator block 108 , exceeds a predetermined threshold.",
"The trip is qualified after three consecutive successful symbol periods.",
"On the other hand, the auxiliary correlator 118 drops the trip and ends qualification after three consecutive unsuccessful correlating periods or after twelve symbol periods have passed without qualification.",
"If no auxiliary correlators 118 are available when a trip signal occurs (i.e., if all four auxiliary correlators 118 are busy qualifying trips), the receiver queues the trip.",
"When a trip signal is qualified, the primary correlators 114 stop searching and the receiver 52 enters the acquisition mode.",
"[0046] The acquisition mode consists of two phases: fine code search and fine frequency search.",
"During fine code search, the receiver 52 sets each primary correlator 114 to the frequency of the qualified trip and sets each of the first sixteen primary correlators 114 to sixteen consecutive phases of the PN sequence separated by one sample.",
"The eighth correlator correlates against the search phase of the qualified trip;",
"the seven preceding correlators correlate against the seven phases, each separated by one sample, immediately preceding the search phase of the qualified trip;",
"and the eight following correlators correlate against the eight phases, each separated by one sample, immediately following the search phase of the qualified trip.",
"The sixteen correlators collect data for one symbol period, with each correlator's correlating period offset a sample behind the correlating period of the preceding correlator.",
"[0047] The outputs of the sixteen correlators undergo a special fine code correlation against an ideal relationship between code phase error and correlator response.",
"This special correlation indicates which offset from the code phase of the qualified trip most closely correlates to the ideal response, which is considered over a range of ±4 samples from perfect code alignment.",
"A normalized ideal response (R) at each sample offset is represented by the following equation: R i =(1−64 i/ 504) 2 , [0048] where i is the offset in samples and −4≦i≦4.",
"The correlation (C) of each sample offset against the ideal response then is determined by the following equation: C j =ΣR i ·O l+j+7 , [0049] where O k is the output of the k th correlator (0≦k<16), where i and j represent the offset in samples (−4≦i,j≦4).",
"For j=−4 and i=−4, “i+j”",
"is less than zero, so the special correlation value at these offset values is disregarded.",
"The best-fit code phase is the one for which the corresponding correlation value (C j ) is largest (“code phase zero”",
"or “data phase zero”).",
"The receiver 52 continues to qualify any outstanding search trips during fine code search but terminates trip qualification when the fine code search stage is successful.",
"[0050] In the fine frequency search phase, which begins after the fine code search is successful, the four auxiliary correlators 118 are used to find the peak of the frequency response to the incoming signal.",
"Each of the auxiliary correlators 118 is set to code phase zero, as determined in the fine code search phase, and to one of several frequencies near the frequency of the qualified trip.",
"Each auxiliary correlator 118 then provides an output representing a point on a frequency response curve, the peak of which represents the signal frequency and may be calculated by the processor.",
"[0051] The receiver 52 also incorporates false peak rejection to ensure that it does not lose valid data packets after detecting and qualifying “false”",
"peaks that may occur at code phases and/or frequencies other than the actual phases and frequencies of the true signals.",
"The processor will recognize a false peak when the signal-to-noise (S/N) ratio of the tripping signal does not improve beyond −13 dB during the fine code and fine frequency search phases.",
"To reject false peaks and to avoid subsequent trips on false peaks from the same signal, the processor drops any signal for which the S/N ratio has not improved by 12 dB after the fine code and fine frequency search phases and sets the trip threshold 6 dB higher than normal during the subsequent search process.",
"Increasing the threshold in this manner should allow the receiver 52 to detect the true peak of a strong signal while ignoring the false peaks.",
"[0052] When the fine code and fine frequency search phases are complete, the receiver 52 begins watching for the sync word.",
"Because the sync word is encoded with 2-CCSK modulation, as described above, the correlator control logic 122 assigns only two primary correlators 114 to monitor the incoming signal for the sync word.",
"The two assigned correlators are the correlator associated with code phase zero, as determined in the fine code search phase, and the correlator immediately following it.",
"The two correlators then correlate the incoming signal against the corresponding code phase over the same correlation period.",
"The correlation outputs of the two correlators are provided to the processor, which assigns each symbol in the sync word a soft value S i according to the equation: S l =( A l −B i )/( A i +B i ), [0053] where A l and B i represent the correlation outputs of the two correlators at each symbol period.",
"The processor stores up to thirteen soft values and, after each symbol period, forms a correlation sum (C) according to the equation: C=ΣS i ·β i , [0054] where the sum runs from i=0 to 12 and where β i represents the actual value of the i th bit of the synch word, with logic levels of ±1.",
"The signal is declared synchronized when the correlation sum is greater than some predetermined threshold.",
"[0055] During the demodulation mode, sixteen of the primary correlators 114 correlate the incoming digital signal to the sixteen different code phases defining the 16-CCSK symbol alphabet, with the first correlator corresponding to code phase zero, as determined during the fine code search phase, and the following correlators successively corresponding to the other fifteen code phases.",
"All sixteen correlators use the same correlation period in the demodulation mode.",
"At the end of each symbol period, the post-correlator processor block 120 determines which correlators have the highest correlation outputs.",
"The processor assigns a symbol value to the symbol period based on which correlator produces the highest correlation output.",
"The processor may be programmed so that it does not assign a symbol value (i.e., it issues an “erasure”) if the ratio of the highest correlation output to the second highest correlation output does not exceed some predetermined threshold.",
"[0056] During demodulation, the receiver also tracks the code phase of the incoming signal.",
"Code phase tracking ensures that the receiver does not lose alignment with the signal as a result of clock drift that may affect the output of the PN sequence generator 116 .",
"To track the code phase, the correlator control logic 122 assigns thirty-two additional primary correlators 114 , half of which provide “early”",
"correlation values and the other half of which provide “late”",
"correlation values.",
"Each “early”",
"correlator is set to a code phase that is between one and four samples ahead of the code phase associated with one of the main demodulation correlators (“on-phase”",
"correlators) discussed above.",
"Each “late”",
"correlator is set to a code phase that is between one and four samples behind the code phase associated with one of the on-phase correlators.",
"The receiver 52 uses the correlation outputs of the early and late correlators associated with the on-phase correlator aligning to the incoming signal during each symbol period to calculate a code phase error (R), according to the equation: R =( E−L )/ O, [0057] where E and L are the outputs of the early and late correlators and O is the output of the on-phase correlator.",
"The code phase error may be used to update the clocking rate of the PN sequence generator 116 when the error is, e.g., greater than {fraction (1/16)} chip.",
"[0058] Referring also to FIGS. 7A and 7B, the receiver begins operation upon startup by initializing the automatic gain control circuit (step 300 ).",
"The receiver then enters the search mode (step 302 ) and continuously searches for a DSSS signal, constantly monitoring and adjusting the AGC circuit (step 304 ), until a trip signal occurs (step 306 ).",
"When a trip signal occurs, the receiver determines whether all of the auxiliary correlators are busy (step 308 ).",
"If so, the receiver queues the trip signal (step 310 ) and continues searching (step 302 );",
"otherwise, the receiver assigns an auxiliary correlator to qualify the trip (step 312 ).",
"The receiver then monitors the qualification process to determine whether the trip signal is qualified or rejected within the allotted period of time (steps 314 and 318 ).",
"If neither qualification nor rejection occurs within twelve symbol periods, the receiver aborts the qualification process for that trip signal (step 316 ) and continues searching for DSSS signals (step 302 ).",
"The receiver also continues searching if the trip signal is disqualified (step 318 ).",
"If, on the other hand, the auxiliary correlator qualifies the trip signal, the receiver enters the acquisition mode.",
"[0059] In the acquisition mode, the receiver first assigns several primary correlators to carry out the fine code search (step 320 ).",
"The receiver then monitors the assigned correlators to determine whether the code phase is successfully acquired (step 322 ).",
"If not, the receiver returns to the search mode and resumes its search for DSSS signals (step 302 );",
"otherwise, the receiver instructs the auxiliary correlators to enter the fine frequency search phase (step 324 ).",
"The receiver then monitors the four general correlators to determine whether the fine frequency search leads to successful acquisition of the frequency offset (step 326 ).",
"If not, the receiver returns to the search mode and resumes searching (step 302 );",
"otherwise, the receiver prepares for sync word detection (step 328 ).",
"If the expected sync word is not detected within the appropriate time limit, the sync word detection process times out (step 330 ) and is aborted (step 316 ), and the receiver again begins searching for DSSS signals (step 302 ).",
"If the sync word is detected, the receiver enters the demodulation mode (step 332 ).",
"In the demodulation mode, the receiver continuously tracks the code phase of the incoming data signal to prevent drift in alignment (step 334 ).",
"If too many erasures occur during demodulation (step 333 ), the demodulation process is aborted (step 316 ) and the receiver again searches for DSSS signals (step 302 ).",
"Otherwise, the receiver continues to demodulate data until the end of the transmitted packet (step 336 ).",
"When the end of the packet is reached, the receiver leaves the demodulation mode, reenters the search mode, and again begins searching for DSSS signals (step 302 ).",
"[0060] Referring now to FIG. 8A, each bandpass correlator (primary and auxiliary) in the receiver may utilize an implementation efficient (IE) correlator structure 130 .",
"As discussed above, the incoming digital signal 131 should enter the correlator at a carrier frequency equal to approximately one-quarter the digital sampling rate (F s /4).",
"The IE correlator structure provides approximate quadrature processing and frequency adjustment in a unified block that requires few and inexpensive components.",
"The structure includes a digital multiplier 132 followed by an accumulation loop 134 having a primary summer 136 and two delay elements 138 and 140 , both of which may be single sample delay registers.",
"The output 141 of the second delay register 140 feeds back to the primary summer 136 and is subtracted from the product output 135 of the multiplier 132 .",
"The output 139 of the first delay register 138 feeds directly into the second delay register 140 .",
"Output 139 also may be provided to a frequency adjustment element 145 that allows the processor to adjust the resonant frequency of the accumulation loop 134 .",
"Within the frequency adjustment element 145 , the output 139 of the first delay register 138 is scaled by a scaling element 144 , fed back to a secondary summer 142 , and added to the output 137 of the primary summer 136 .",
"The correlator structure 130 may be implemented in standard, off-the-shelf components, but it is particularly suited for implementation in an application specific integrated circuit (ASIC).",
"[0061] In operation, the incoming digital signal 131 and a local copy of the PN sequence 133 are provided as inputs to the multiplier 132 .",
"If the two are in code phase alignment, the code product always equals “1”",
"and the output 135 of the multiplier is simply the F s /4 carrier wave.",
"Because the loop delay is two samples, the output 141 of the second delay register 140 is approximately 180° out-of-phase with the multiplier output 135 and therefore reinforces the multiplier output 135 in the primary summer 136 during the subtraction operation.",
"The input 143 and the output 149 of the first delay register 138 differ by one sample time and therefore are approximately 90° out-of-phase, so they may be taken as the in-phase and quadrature components, respectively, of the F s /4 carrier wave.",
"At the end of the accumulation time (one correlation period), the in-phase and quadrature outputs are taken and the delay registers 138 and 140 both are set to zero to re-initialize the accumulation loop 134 .",
"The final output 151 is the sum of the squares of the in-phase and quadrature components at the end of each correlation period, as provided by squaring circuits 146 and 148 and adder 150 .",
"[0062] Instead of a single-sample, register 140 may delay output 139 by multiple samples, so that the phase offset between output 135 and output 141 is a multiple of 180°.",
"For example, a three sample delay in register 140 leaves output 141 360° out-of-phase with product output 135 .",
"In this case, primary summer 136 will add output 141 to product output 135 to form an accumulation output.",
"[0063] The frequency adjustment element 145 includes a scaling element 144 , the scaling factor (K) of which is variable to allow for frequency adjustment within the correlator's accumulation loop 134 .",
"The scaling factor K has a value equal to 2·cos(Ω 0 ), where Ω 0 represents 2π times the ratio of the desired resonant frequency of the accumulation loop 134 to the sampling rate (F s ) of the A/D converter 104 (the absolute value of K typically will be much less than one).",
"The value of the scaling factor may be selected by the processor and stored in a programmable storage element 144 b such as a register.",
"A multiplication element 144 a applies the scaling factor to the output 139 of the first delay register 138 , and the resulting signal is added by the secondary summer 142 to the output 137 of the primary summer 136 .",
"When the scaling factor has a value of zero, the secondary summer 142 has no effect on the correlator structure.",
"However, when the scaling factor is slightly above or below zero, the effective delay in the accumulation loop 134 is slightly greater than or less than two samples, so the loop response is centered at a frequency slightly below or slightly above F s /4.",
"Since the delay between the output 139 of delay element 138 and the output 141 of delay element 140 always remains at one sample, adjusting the scaling factor to a value other than zero introduces a small quadrature error at frequencies offset from F s /4.",
"At small frequency offsets, the quadrature error is insignificant.",
"[0064] Referring to FIG. 8B, a quadrature error correction element 160 may be added to the correlator structure 130 to eliminate the quadrature error introduced by the scaling element 144 .",
"The correction element 160 includes two multiplication elements 162 and 164 , which multiply the output 139 of the accumulation loop 134 with signals equal to cos(Ω 0 ) and sin(Ω 0 ).",
"The output 165 of multiplication element 164 represents the corrected quadrature component of the accumulation output and is provided to squaring circuit 148 .",
"Summer 166 produces the corrected in-phase component of the accumulation output by subtracting the output 163 of multiplication element 162 from the output 143 of secondary summer 142 .",
"The corrected in-phase component is provided to squaring circuit 146 .",
"[0065] Referring also to FIG. 9, when a binary PN sequence serves as the spreading signal, the digital multiplier 132 may be a simple sign inverter realized, e.g., as a digital multiplexer 155 receiving the incoming digital signal 131 and an inverted version 131 ′ of this signal as inputs and having a local copy of the PN sequence 133 as its control signal.",
"The non-inverted signal 131 ′ is selected by the multiplexer 155 when the PN sequence 133 is high, and the inverted signal 131 ′ is selected when the PN sequence 133 is low.",
"When the incoming signal 131 and the PN sequence 133 are aligned, the PN sequence cancels the spreading signal from the incoming signal 131 and only the F s /4 carrier wave exits the multiplexer 155 .",
"[0066] Other embodiments are within the scope of the following claims."
] |
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